JoVE Visualize What is visualize?
Stop Reading. Start Watching.
Advanced Search
Stop Reading. Start Watching.
Regular Search
Find video protocols related to scientific articles indexed in Pubmed.
Effects of Regular Away Travel on Training Loads, Recovery and Injury Rates in Professional Australian Soccer Players.
Int J Sports Physiol Perform
PUBLISHED: 11-14-2014
Show Abstract
Hide Abstract
The present study examined the acute and longitudinal effects of regular away travel on training loads (TL), player wellness and injury surrounding competitive soccer (football) matches. Eighteen male professional football players, representing a team competing in the highest national competition in Australia, volunteered to participate in the study. Training loads, player wellness and injury incidence, rate, severity and type, together with the activity at the time of injury were recorded on the day prior to, the day of and for four days following each of the 27 matches of the 2012/2013 season. This included 14 home and 13 away matches, further subdivided based on the mid-point of the season into early (1-13) and late competition (14-27) phases. Whilst TL were significantly greater on day 3 at home compared to away during the early competition phase (p=0.03), no other significant effects of match location were identified (p>0.05). Total TL and mean wellness over the six days surrounding matches, and TL on day 3 were significantly reduced during the late compared to the early competition phase at home and away (p<0.05). Though not significant (p>0.05), training missed due to injury was 60 and 50 % greater during the late compared to the early competition phase at home and away, respectively. In conclusion, no significant interactions between match location and competition phase were evident during the late competition phase, which suggests away travel had negligible cumulative effects on the reduction in player wellness in the latter half of the season.
Related JoVE Video
Sleep and Athletic Performance: The Effects of Sleep Loss on Exercise Performance, and Physiological and Cognitive Responses to Exercise.
Sports Med
PUBLISHED: 10-16-2014
Show Abstract
Hide Abstract
Although its true function remains unclear, sleep is considered critical to human physiological and cognitive function. Equally, since sleep loss is a common occurrence prior to competition in athletes, this could significantly impact upon their athletic performance. Much of the previous research has reported that exercise performance is negatively affected following sleep loss; however, conflicting findings mean that the extent, influence, and mechanisms of sleep loss affecting exercise performance remain uncertain. For instance, research indicates some maximal physical efforts and gross motor performances can be maintained. In comparison, the few published studies investigating the effect of sleep loss on performance in athletes report a reduction in sport-specific performance. The effects of sleep loss on physiological responses to exercise also remain equivocal; however, it appears a reduction in sleep quality and quantity could result in an autonomic nervous system imbalance, simulating symptoms of the overtraining syndrome. Additionally, increases in pro-inflammatory cytokines following sleep loss could promote immune system dysfunction. Of further concern, numerous studies investigating the effects of sleep loss on cognitive function report slower and less accurate cognitive performance. Based on this context, this review aims to evaluate the importance and prevalence of sleep in athletes and summarises the effects of sleep loss (restriction and deprivation) on exercise performance, and physiological and cognitive responses to exercise. Given the equivocal understanding of sleep and athletic performance outcomes, further research and consideration is required to obtain a greater knowledge of the interaction between sleep and performance.
Related JoVE Video
The Relationship of Training Load to Physical Capacity Changes During International Tours in High Performance Junior Tennis Players.
Int J Sports Physiol Perform
PUBLISHED: 08-12-2014
Show Abstract
Hide Abstract
Given the travel that punctuates junior tennis development, an understanding of the changes in fitness owing to touring and the association between training loads (TL's) and fitness upon return, is vital. We investigated physical capacity changes from pre to post tour, determining if those changes were related to the TL's of athletes on tour.
Related JoVE Video
An equivalent circuit model for onset and offset exercise response.
Biomed Eng Online
PUBLISHED: 08-01-2014
Show Abstract
Hide Abstract
The switching exercise (e.g., Interval Training) has been a commonly used exercise protocol nowadays for the enhancement of exerciser's cardiovascular fitness. The current difficulty for simulating human onset and offset exercise responses regarding the switching exercise is to ensure the continuity of the outputs during onset-offset switching, as well as to accommodate the exercise intensities at both onset and offset of exercise.
Related JoVE Video
Effects of sleep hygiene and artificial bright light interventions on recovery from simulated international air travel.
Eur. J. Appl. Physiol.
PUBLISHED: 06-05-2014
Show Abstract
Hide Abstract
Despite the reported detrimental effects of international air travel on physical performance, a paucity of interventions have been scientifically tested and confirmed to benefit travelling athletes. Consequently, the aim of the present study was to examine the effects of sleep hygiene and artificial bright light interventions on physical performance following simulated international travel.
Related JoVE Video
Tennis for physical health: acute age- and gender-based physiological responses to cardio tennis.
J Strength Cond Res
PUBLISHED: 05-07-2014
Show Abstract
Hide Abstract
Murphy, AP, Duffield, R, and Reid, M. Tennis for physical health: Acute age- and gender-based physiological responses to Cardio tennis. J Strength Cond Res 28(11): 3177-3183, 2014-This study described physiological and perceptual responses to Cardio tennis for "younger" and "older" adult populations of both sexes for health-related outcomes. Thirty-one active participants, each with prior recreational tennis experience (?2 years) (8 younger and 8 older males, and 7 younger and 8 older females) performed preliminary testing and a 50-minute instructor-led Cardio tennis session. Cardio tennis is a conditioning-based tennis program comprised of warm-up movements, drill-based exercises (set movement and hitting games), and competitive play scenarios. Participants performed the 20-m shuttle run test to determine maximal heart rate (HR) during preliminary testing. Before, after, and 30-minute post Cardio tennis session, HR, blood pressure (BP), rate pressure product (RPP), and capillary blood lactate and glucose were determined. Furthermore, HR and pedometer-derived step counts were measured throughout, while the session was filmed and coded for technical skill. After the session, ratings of perceived exertion, enjoyment, and challenge were obtained. Heart rate, systolic BP, and RPP were significantly increased by Cardio tennis (p ? 0.05), though returned to pre-exercise levels after 30 minutes (p > 0.05). Heart rate and BP did not differ between groups pre- or 30-minute postexercise (p > 0.05); however, these were lower in younger males during and higher in younger females postsession (p ? 0.05). Lactate and glucose concentrations were increased in all groups (p ? 0.05), with lactate being highest in male groups (p ? 0.05), without differences in glucose between groups (p > 0.05). Stroke and step counts were not different between groups (p > 0.05). Ratings of perceived exertion and perceived challenge were lowest in the younger male group compared with all other groups (p ? 0.05). Cardio tennis presents as an effective stimulus to invoke sufficient cardiovascular and metabolic load to benefit health and fitness, though age- and sex-based responses should be considered in prescription.
Related JoVE Video
Effects of domestic air travel on technical and tactical performance and recovery in soccer.
Int J Sports Physiol Perform
PUBLISHED: 04-24-2014
Show Abstract
Hide Abstract
The current study examined the effects of short-haul air travel on competition performance and subsequent recovery. Six male professional Australian football (soccer) players were recruited to participate in the study. Data were collected from 12 matches, which included 6 home and away matches against the same 4 teams. Together with the outcome of each match, data were obtained for team technical and tactical performance indicators and individual player-movement patterns. Furthermore, sleep quantity and quality, hydration, and perceptual fatigue were measured 2 days before, the day of, and 2 days after each match. More competition points were accumulated (P > .05, d = 1.10) and fewer goals were conceded (P > .05, d = 0.93) in home than in away matches. Furthermore, more shots on goal (P > .05, d = 1.17) and corners (P > .05, d = 1.45) and fewer opposition shots on goal (P > .05, d = 1.18) and corners (P < .05, d = 2.32) occurred, alongside reduced total distance covered (P > .05, d = 1.19) and low-intensity activity (P < .05, d = 2.25) during home than during away matches. However, while oxygen saturation was significantly lower during than before and after outbound and return travel (P < .01), equivocal differences in sleep quantity and quality, hydration, and perceptual fatigue were observed before and after competition away compared with home. These results suggest that, compared with short-haul air travel, factors including situational variables, territoriality, tactics, and athlete psychological state are more important in determining match outcome. Furthermore, despite the potential for disrupted recovery patterns, return travel did not impede player recovery or perceived readiness to train.
Related JoVE Video
The development of fatigue during match-play tennis.
Br J Sports Med
PUBLISHED: 03-27-2014
Show Abstract
Hide Abstract
Data describing the activity profile and physiological characteristics of tennis match-play are extensive. However, these data have generally provided descriptive accounts of the one-off match-play of amateur or lowly ranked professional players lasting <3 h. Accordingly, these research efforts have likely failed to fully capture the demands of Grand Slam tennis match-play, particularly in the men's game where matches can last >5 h. Furthermore, there is a distinct lack of evidence-based insight regarding the manifestation of fatigue within and between tennis matches, notwithstanding that skeletal muscle function has been reported to reduce following prolonged match-play. Moreover, it is evident that match-play evokes pronounced and prolonged physiological, neuromuscular and psychological perturbations that may be exacerbated with consecutive days of match-play. Separate to these internal load responses, a collection of non-uniform movement and technical performance changes are reported, though rarely from match-play data. Consequently, direct or causal links between altered physiological or muscle contractile function and subsequent match-play outcomes are lacking. Indeed, emerging evidence seems to infer that players adjust their game strategy, and the resultant execution of stroke play, to accommodate any such deterioration in physiological function. The purpose of this review was to discuss the available literature in terms of the physiological, mechanical and psychological responses that occur during prolonged match-play in the context of their likely effect on match-play performance.
Related JoVE Video
A 12-week sports-based exercise programme for inactive Indigenous Australian men improved clinical risk factors associated with type 2 diabetes mellitus.
J Sci Med Sport
PUBLISHED: 03-06-2014
Show Abstract
Hide Abstract
This study assessed the effect of a 12-week sports-based exercise intervention on glucose regulation, anthropometry and inflammatory markers associated with the prevalence of type 2 diabetes mellitus (T2DM) in Indigenous Australian men.
Related JoVE Video
Small-sided games training reduces CRP, IL-6 and leptin in sedentary, middle-aged men.
Eur. J. Appl. Physiol.
PUBLISHED: 02-25-2014
Show Abstract
Hide Abstract
Long-term physical activity is reported to improve chronic systemic inflammation, which provides protection against the ensuing development of chronic disease. Accordingly, the present study assessed changes in pro- and anti-inflammatory cytokines, aerobic capacity and body composition following 8 weeks of either small-sided games (SSG) or cycling (CYC) training compared to a sedentary control (CON) condition.
Related JoVE Video
A descriptive analysis of internal and external loads for elite-level tennis drills.
Int J Sports Physiol Perform
PUBLISHED: 02-07-2014
Show Abstract
Hide Abstract
Planning tennis sessions accentuating physical development requires an understanding of training load (TL). The aims were to describe the external and internal TL of drills and analyze relationships between ratings of perceived exertion (RPE), TL, and other measures.
Related JoVE Video
Cytokine mRNA expression responses to resistance, aerobic, and concurrent exercise in sedentary middle-aged men.
Appl Physiol Nutr Metab
PUBLISHED: 01-31-2014
Show Abstract
Hide Abstract
Concurrent resistance and aerobic exercise (CE) is recommended to ageing populations, though is postulated to induce diminished acute molecular responses. Given that contraction-induced cytokine mRNA expression reportedly mediates remunerative postexercise molecular responses, it is necessary to determine whether cytokine mRNA expression may be diminished after CE. Eight middle-aged men (age, 53.3 ±1.8 years; body mass index, 29.4 ± 1.4 kg·m(-2)) randomly completed (balanced for completion order) 8 × 8 leg extensions at 70% maximal strength (RE), 40 min of cycling at 55% of peak aerobic workload (AE), or (workload-matched) 50% RE and 50% AE (CE). Muscle (vastus lateralis) was obtained pre-exercise, and at 1 h and 4 h postexercise, and analyzed for changes of glycogen concentration, tumor necrosis factor (TNF)?, TNF receptor-1 and -2 (TNF-R1 and TNF-R2, respectively), interleukin (IL)-6, IL-6R, IL-1?, and IL-1 receptor-antagonist (IL-1ra). All exercise modes upregulated cytokine mRNA expression at 1 h postexercise comparably (TNF?, TNF-R1, TNF-R2, IL-1?, IL-6) (p < 0.05). Expression remained elevated at 4 h after RE and AE (p < 0.05), though returned to pre-exercise levels after CE (p > 0.05). Moreover, AE and RE upregulated IL-1? and IL-1ra expression, whereas CE upregulated IL-1? expression only (p < 0.05). Only AE reduced muscle glycogen concentration (p < 0.05), whilst upregulating receptor expression the greatest; though, IL-6R expression remained unchanged after all modes (p > 0.05). In conclusion, in middle-aged men, all modes induced commensurate cytokine mRNA expression at 1 h postexercise; however, only CE resulted in ameliorated expression at 4 h postexercise. Whether the RE or AE components of CE are independently or cumulatively sufficient to upregulate cytokine responses, or whether they collectively inhibit cytokine mRNA expression, remains to be determined.
Related JoVE Video
Physiological, movement and technical demands of centre-wicket Battlezone, traditional net-based training and one-day cricket matches: a comparative study of sub-elite cricket players.
J Sports Sci
PUBLISHED: 01-10-2014
Show Abstract
Hide Abstract
This study compared physiological, physical and technical demands of Battlezone, traditional cricket training and one-day matches. Data were initially collected from 11 amateur, male cricket players (age: 22.2 ± 3.3 year, height: 1.82 ± 0.06 m body mass: 80.4 ± 9.8 kg) during four Battlezone and four traditional cricket training sessions encompassing different playing positions. Heart rate, blood lactate concentration, rating of perceived exertion and movement patterns of players were measured. Retrospective video analysis was performed to code for technical outcomes. Similar data were collected from 42 amateur, male cricket players (23.5 ± 4.7 year, 1.81 ± 0.07 m, 81.4 ± 11.4 kg) during one-day matches. Significant differences were found between Battlezone, traditional cricket training and one-day matches within each playing position. Specifically, Battlezone invoked the greatest physiological and physical demands from batsmen in comparison to traditional cricket training and one-day matches. However, the greatest technical demand for batsmen was observed during traditional cricket training. In regards to the other playing positions, a greater physiological, physical and technical demand was observed during Battlezone and traditional training than during one-day matches. These results suggest that the use of Battlezone and traditional cricket training provides players with a suitable training stimulus for replicating the physiological, physical and technical demands of one-day cricket.
Related JoVE Video
Is recovery driven by central or peripheral factors? A role for the brain in recovery following intermittent-sprint exercise.
Front Physiol
PUBLISHED: 01-01-2014
Show Abstract
Hide Abstract
Prolonged intermittent-sprint exercise (i.e., team sports) induce disturbances in skeletal muscle structure and function that are associated with reduced contractile function, a cascade of inflammatory responses, perceptual soreness, and a delayed return to optimal physical performance. In this context, recovery from exercise-induced fatigue is traditionally treated from a peripheral viewpoint, with the regeneration of muscle physiology and other peripheral factors the target of recovery strategies. The direction of this research narrative on post-exercise recovery differs to the increasing emphasis on the complex interaction between both central and peripheral factors regulating exercise intensity during exercise performance. Given the role of the central nervous system (CNS) in motor-unit recruitment during exercise, it too may have an integral role in post-exercise recovery. Indeed, this hypothesis is indirectly supported by an apparent disconnect in time-course changes in physiological and biochemical markers resultant from exercise and the ensuing recovery of exercise performance. Equally, improvements in perceptual recovery, even withstanding the physiological state of recovery, may interact with both feed-forward/feed-back mechanisms to influence subsequent efforts. Considering the research interest afforded to recovery methodologies designed to hasten the return of homeostasis within the muscle, the limited focus on contributors to post-exercise recovery from CNS origins is somewhat surprising. Based on this context, the current review aims to outline the potential contributions of the brain to performance recovery after strenuous exercise.
Related JoVE Video
Comparison of Athlete-Coach Perceptions of Internal and External Load Markers for Elite Junior Tennis Training.
Int J Sports Physiol Perform
PUBLISHED: 11-14-2013
Show Abstract
Hide Abstract
To investigate the discrepancy between coach and athlete perceptions of internal load and notational analysis of external load in elite junior tennis.
Related JoVE Video
The effect of post-match alcohol ingestion on recovery from competitive rugby league matches.
J Strength Cond Res
PUBLISHED: 11-06-2013
Show Abstract
Hide Abstract
This study investigated the effects of alcohol ingestion on lower-body strength and power and physiological and cognitive recovery after competitive Rugby League matches. Nine male Rugby players participated in 2 matches, followed by 1 of 2 randomized interventions, a control or alcohol ingestion session. Four hours post-match, participants consumed either beverages containing a total of 1 g of ethanol per kilogram bodyweight (vodka and orange juice; ALC) or a caloric and taste-matched nonalcoholic beverage (orange juice; CONT). Before the match, immediately post-match, 2 hours post-, and 16 hours post-match measures of countermovement jump (CMJ); maximal voluntary contraction (MVC); voluntary activation (VA); and damage and stress markers of creatine kinase (CK), C-reactive protein (CRP), cortisol, and testosterone analyzed from venous blood collection; and cognitive function (modified Stroop test) were determined. Alcohol resulted in large effects for decreased CMJ height (-2.35 ± 8.14% and -10.53 ± 8.36% decrement for CONT and ALC, respectively; p = 0.15, d = 1.40), without changes in MVC (p = 0.52, d = 0.70) or VA (p = 0.15, d = 0.69). Furthermore, alcohol resulted in a significant slowing of total time in a cognitive test (p = 0.04, d = 1.59) while exhibiting large effects for detriments in congruent reaction time (p = 0.19, d = 1.73). Despite large effects for increased cortisol after alcohol ingestion during recovery (p = 0.28, d = 1.44), post-match alcohol consumption did not unduly affect testosterone (p = 0.96, d = 0.10), CK (p = 0.66, d = 0.70), or CRP (p = 0.75, d = 0.60). It seems that alcohol consumption during the evening after competitive rugby matches may have some detrimental effects on peak power and cognitive recovery the morning after a Rugby League match. Accordingly, practitioners should be aware of the potential associated detrimental effects of alcohol consumption on recovery and provide alcohol awareness to athletes at post-match functions.
Related JoVE Video
Differences in post-exercise inflammatory and glucose regulatory response between sedentary indigenous australian and caucasian men completing a single bout of cycling.
Am. J. Hum. Biol.
PUBLISHED: 09-16-2013
Show Abstract
Hide Abstract
This study compared the acute inflammatory and glucose responses following aerobic exercise in sedentary Indigenous Australian and Caucasian men, matched for fitness and body composition.
Related JoVE Video
Physiological, perceptual, and technical responses to on-court tennis training on hard and clay courts.
J Strength Cond Res
PUBLISHED: 07-31-2013
Show Abstract
Hide Abstract
The aim of this study was to investigate the effect of court surface (clay vs. hard court) on technical, physiological, and perceptual responses to on-court tennis training. Four high-performance junior male players performed 2 identical training sessions on hard and clay courts, respectively. Sessions included both physical conditioning and technical elements as led by the coach. Each session was filmed for later notational analysis of stroke count and error rates. Furthermore, players wore a global positioning satellite device to measure distance covered during each session, while heart rate, countermovement jump distance, and capillary blood measures of metabolites were measured before, during, and after each session. Additionally, a respective coach and athlete rating of perceived exertion (RPE) were measured after each session. Total duration and distance covered during each session were comparable (p > 0.05; d < 0.20). Although forehand and backhands stroke volume did not differ between sessions (p > 0.05; d < 0.30), large effects for increased unforced and forced errors were present on the hard court (p > 0.05; d > 0.90). Furthermore, large effects for increased heart rate, blood lactate, and RPE values were evident on clay compared with hard courts (p > 0.05; d > 0.90). Additionally, although player and coach RPE on hard courts were similar, there were large effects for coaches to underrate the RPE of players on clay courts (p > 0.05; d > 0.90). In conclusion, training on clay courts results in trends for increased heart rate, lactate, and RPE values, suggesting that sessions on clay courts tend towards higher physiological and perceptual loads than hard courts. Furthermore, coaches seem effective at rating player RPE on hard courts but may underrate the perceived exertion of sessions on clay courts.
Related JoVE Video
Recovery From Repeated On-Court Tennis Sessions: Combining Cold Water Immersion, Compression and Sleep Recovery Interventions.
Int J Sports Physiol Perform
PUBLISHED: 06-24-2013
Show Abstract
Hide Abstract
The current study investigated the effects of combining cold water immersion (CWI), full-body compression garments (CG) and sleep hygiene recommendations on physical, physiological and perceptual recovery following two a day, on-court training and match-play sessions.
Related JoVE Video
Comparative effects of single-mode vs. duration-matched concurrent exercise training on body composition, low-grade inflammation, and glucose regulation in sedentary, overweight, middle-aged men.
Appl Physiol Nutr Metab
PUBLISHED: 02-25-2013
Show Abstract
Hide Abstract
The effect of duration-matched concurrent exercise training (CET) (50% resistance (RET) and 50% endurance (EET) training) on physiological training outcomes in untrained middle-aged men remains to be elucidated. Forty-seven men (age, 48.1 ± 6.8 years; body mass index, 30.4 ± 4.1 kg·m(-2)) were randomized into 12-weeks of EET (40-60 min of cycling), RET (10 exercises; 3-4 sets × 8-10 repetitions), CET (50% serial completion of RET and EET), or control condition. The following were determined: intervention-based changes in fitness and strength; abdominal visceral adipose tissue (VAT), total body fat (TB-FM) and fat-free (TB-FFM) mass; plasma cytokines (C-reactive protein (CRP), tumor necrosis factor-? (TNF?) interleukin-6 (IL-6)); muscle protein content of p110? and glucose transporter 4 (GLUT4); mRNA expression of GLUT4, peroxisome proliferator-activated receptor-? coactivator-1?-?, cytochrome c oxidase, hexokinase II, citrate synthase; oral glucose tolerance; and estimated insulin sensitivity. CET promoted commensurate improvements of aerobic capacity and muscular strength and reduced VAT and TB-FM equivalently to EET and RET (p < 0.05), yet only RET increased TB-FFM (p < 0.05). Although TNF? and IL-6 were reduced after all training interventions (p < 0.05), CRP remained unchanged (p > 0.05). EET reduced area under the curve for glucose, insulin, and C-peptide, whilst CET and RET respectively reduced insulin and C-peptide, and C-peptide only (p < 0.05). Notwithstanding increased insulin sensitivity index after all training interventions (p < 0.05), no change presented for GLUT4 or p110? total protein, or chronic mRNA expression of the studied mitochondrial genes (p > 0.05). In middle-aged men, 12 weeks of duration-matched CET promoted commensurate changes in fitness and strength, abdominal VAT, plasma cytokines and insulin sensitivity, and an equidistant glucose tolerance response to EET and RET; despite no change of measured muscle mechanisms associative to insulin action, glucose transport, and mitochondrial function.
Related JoVE Video
The effect of overnight sleep deprivation after competitive rugby league matches on postmatch physiological and perceptual recovery.
Int J Sports Physiol Perform
PUBLISHED: 02-14-2013
Show Abstract
Hide Abstract
This study examined the effects of overnight sleep deprivation on recovery after competitive rugby league matches.
Related JoVE Video
Post-match changes in neuromuscular function and the relationship to match demands in amateur rugby league matches.
J Sci Med Sport
PUBLISHED: 08-16-2011
Show Abstract
Hide Abstract
The current study investigated the change in neuromuscular contractile properties following competitive rugby league matches and the relationship with physical match demands.
Related JoVE Video
The effects of carbohydrate intake and muscle glycogen content on self-paced intermittent-sprint exercise despite no knowledge of carbohydrate manipulation.
Eur. J. Appl. Physiol.
PUBLISHED: 08-11-2011
Show Abstract
Hide Abstract
The aim of this study was to determine the effects of carbohydrate (CHO) ingestion and muscle glycogen content, without the influence of knowledge of CHO consumption, on intermittent-sprint performance. Ten males completed two conditions on two consecutive days. Day 1 involved 2 × 40 min of leg cycling separated by 15 min of arm cycling, followed by an overnight diet consuming either a high [HCHO; 7 g/kg body weight (bw)] or low (LCHO; 2 g/kg bw) CHO diet. Participants were blinded to the knowledge CHO was being examined or manipulated. Day 2 included a 60-min intermittent-sprint exercise (ISE) protocol that included 15-m maximal sprints every minute and self-paced efforts of varying intensities. Pre and post-ISE muscle biopsies were obtained on Day 2. Pre- and post-exercise maximal voluntary torque (MVT), voluntary activation (VA) and twitch contractile properties were assessed during 15 maximal isometric contractions. Blood glucose and lactate, heart rate (HR) and rating of perceived exertion (RPE) were also recorded. Pre-ISE muscle glycogen was greater in HCHO compared with LCHO (597 ± 115 vs. 318 ± 72 mmol kg dry weight; P = 0.001). Total distance and hard running distance were 4.9 and 8.1% greater in HCHO, respectively (P = 0.02-0.04). Peak MVT, VA, HR and RPE were not different between conditions (P > 0.05). Blood glucose was higher pre-ISE for LCHO but lower post-ISE compared with HCHO (P < 0.05). These results indicate HCHO improved self-paced exercise intensities during the ISE protocol despite no knowledge of dietary manipulation. Due to the blinded study design, exercise intensities seem manipulated due to peripheral perturbations associated with CHO content rather than a conscious manipulation of exercise intensities.
Related JoVE Video
Field-based pre-cooling for on-court tennis conditioning training in the heat.
J Sports Sci Med
PUBLISHED: 06-01-2011
Show Abstract
Hide Abstract
The present study investigated the effects of pre-cooling for on- court, tennis-specific conditioning training in the heat. Eight highly-trained tennis players performed two on-court conditioning sessions in 35°C, 55% Relative Humidity. Sessions were randomised, involved either a pre-cooling or control session, and consisted of 30-min of court- based, tennis movement drills. Pre-cooling involved 20-min of an ice-vest and cold towels to the head/neck and legs, followed by warm-up in a cold compression garment. On-court movement distance was recorded by 1Hz Global Positioning Satellite (GPS) devices, while core temperature, heart rate and perceptual exertion and thermal stress were also recorded throughout the session. Additionally, mass and lower-body peak power during repeated counter-movement jumps were measured before and after each session. No significant performance differences were evident between conditions, although a moderate-large effect (d = 0.7-1.0; p > 0.05) was evident for total (2989 ± 256 v 2870 ± 159m) and high-intensity (805 ± 340 v 629 ± 265m) distance covered following pre-cooling. Further, no significant differences were evident between conditions for rise in core temperature (1.9 ± 0.4 v 2. 2 ± 0.4°C; d > 0.9; p > 0.05), although a significantly smaller change in mass (0.9 ± 0.3 v 1. 3 ± 0.3kg; p < 0.05) was present following pre-cooling. Perceived thermal stress and exertion were significantly lower (d > 1.0; p < 0.05) during the cooling session. Finally, lower-body peak power did not differ between conditions before or after training (d < 0.3; p > 0.05).
Related JoVE Video
Volume-dependent response of precooling for intermittent-sprint exercise in the heat.
Med Sci Sports Exerc
PUBLISHED: 02-12-2011
Show Abstract
Hide Abstract
This study aimed to assess the effects of precooling volume on neuromuscular function and performance in free-paced intermittent-sprint exercise in the heat.
Related JoVE Video
Cold water immersion recovery following intermittent-sprint exercise in the heat.
Eur. J. Appl. Physiol.
PUBLISHED: 02-01-2011
Show Abstract
Hide Abstract
This study examined the effects of cold water immersion (CWI) on recovery of neuromuscular function following simulated team-sport exercise in the heat. Ten male team-sport athletes performed two sessions of a 2 × 30-min intermittent-sprint exercise (ISE) in 32°C and 52% humidity, followed by a 20-min CWI intervention or passive recovery (CONT) in a randomized, crossover design. The ISE involved a 15-m sprint every minute separated by bouts of hard running, jogging and walking. Voluntary and evoked neuromuscular function, ratings of perceived muscle soreness (MS) and blood markers for muscle damage were measured pre- and post-exercise, immediately post-recovery, 2-h and 24-h post-recovery. Measures of core temperature (Tcore), heart rate (HR), capillary blood and perceptions of exertion, thermal strain and thirst were also recorded at the aforementioned time points. Post-exercise maximal voluntary contraction (MVC) and activation (VA) were reduced in both conditions and remained below pre-exercise values for the 24-h recovery (P < 0.05). Increased blood markers of muscle damage were observed post-exercise in both conditions and remained elevated for the 24-h recovery period (P < 0.05). Comparative to CONT, the post-recovery rate of reduction in Tcore, HR and MS was enhanced with CWI whilst increasing MVC and VA (P < 0.05). In contrast, 24-h post-recovery MVC and activation were significantly higher in CONT compared to CWI (P = 0.05). Following exercise in the heat, CWI accelerated the reduction in thermal and cardiovascular load, and improved MVC alongside increased central activation immediately and 2-h post-recovery. However, despite improved acute recovery CWI resulted in an attenuated MVC 24-h post-recovery.
Related JoVE Video
Cold application for neuromuscular recovery following intense lower-body exercise.
Eur. J. Appl. Physiol.
PUBLISHED: 01-17-2011
Show Abstract
Hide Abstract
This study examined the effects of cold therapy (COLD) on recovery of voluntary and evoked contractile properties following high-intensity, muscle-damaging and fatiguing exercise. Ten resistance-trained males performed 6 × 25 maximal concentric/eccentric muscle contractions of the dominant knee extensors (KE) followed by a 20-min recovery (COLD v control) in a randomized cross-over design. Voluntary and evoked neuromuscular properties of the right KE, ratings of perceived muscle soreness (MS) and pain, and blood markers for muscle damage were measured pre- and post-exercise, and immediately post-recovery, 2, 24 and 48-h post-recovery. Exercise resulted in decrements in voluntary and evoked torque, increased MS and elevated muscle damage markers (p < 0.05). Measures of maximal voluntary contraction (MVC) or voluntary activation (VA) were not significantly enhanced by COLD (p > 0.05). Activation of right KE decreased post-exercise with increased activation of biceps femoris (BF) (p < 0.05). However, no significant differences were evident between conditions of activation of KE and hamstrings at any time point (p > 0.05). No significant differences were observed between conditions for creatine kinase or asparate aminotransferase (p > 0.05). However, perceptual ratings of pain were significantly (p < 0.05) lower following COLD compared to control. In conclusion, following damage to the contractile apparatus, COLD did not significantly hasten the recovery of peripheral contractile trauma. Despite no beneficial effect of COLD on recovery of MVC, perceptions of pain were reduced following COLD.
Related JoVE Video
Self-paced intermittent-sprint performance and pacing strategies following respective pre-cooling and heating.
Eur. J. Appl. Physiol.
PUBLISHED: 01-12-2011
Show Abstract
Hide Abstract
This study examined the effects of pre-exercise cooling and heating on neuromuscular function, pacing and intermittent-sprint performance in the heat. Ten male, team sport athletes completed three randomized, counterbalanced conditions including a thermo-neutral environment (CONT), whole body submersion in an ice bath (ICE) and passive heating in a hot environment (HEAT) before 50 min of intermittent-sprint exercise (ISE) in the heat (31 + 1°C). Exercise involved repeated 15 m maximal sprints and self-paced exercise of varying intensities. Performance was measured by sprint times and distance covered during self-paced exercise. Maximal isometric contractions were performed to determine the maximal voluntary torque (MVT), activation (VA) and contractile properties. Physiological measures included heart rate (HR), core (T (core)) and skin (T (skin)) temperatures, capillary blood and perceptual ratings. Mean sprint times were slower during ICE compared to HEAT (P < 0.05). Total distance covered was not different between conditions, but less distance was covered during HEAT in 31-40 min compared to CONT, and 41-50 min compared to ICE (P < 0.05). MVT was reduced post-exercise compared to post-intervention in CONT and HEAT. VA was reduced post-intervention in HEAT compared to CONT and ICE, and post-exercise compared to ICE (P < 0.05). HR, T (core) and T (skin) during exercise were lower in ICE compared to CONT and HEAT (P < 0.05). Sprint times and distance covered were not affected by ICE and HEAT conditions compared to CONT. However, initial sprint performance was slowed by pre-cooling, with improvements following passive heating possibly due to altered contractile properties. Conversely, pre-cooling improved exercise intensities, whilst HEAT resulted in greater declines in muscle recruitment and ensuing distance covered.
Related JoVE Video
Intermittent-sprint performance and muscle glycogen after 30 h of sleep deprivation.
Med Sci Sports Exerc
PUBLISHED: 01-05-2011
Show Abstract
Hide Abstract
The aim of this study was to determine the effects of 30 h of sleep deprivation on consecutive-day intermittent-sprint performance and muscle glycogen content.
Related JoVE Video
Short term effects of various water immersions on recovery from exhaustive intermittent exercise.
Eur. J. Appl. Physiol.
PUBLISHED: 11-18-2010
Show Abstract
Hide Abstract
In order to investigate the effectiveness of different techniques of water immersion recovery on maximal strength, power and the post-exercise inflammatory response in elite athletes, 41 highly trained (Football, Rugby, Volleyball) male subjects (age = 21.5 ± 4.6 years, mass = 73.1 ± 9.7 kg and height = 176.7 ± 9.7 cm) performed 20 min of exhaustive, intermittent exercise followed by a 15 min recovery intervention. The recovery intervention consisted of different water immersion techniques, including: temperate water immersion (36°C; TWI), cold water immersion (10°C; CWI), contrast water temperature (10-42°C; CWT) and a passive recovery (PAS). Performances during a maximal 30-s rowing test (P(30 s)), a maximal vertical counter-movement jump (CMJ) and a maximal isometric voluntary contraction (MVC) of the knee extensor muscles were measured at rest (Pre-exercise), immediately after the exercise (Post-exercise), 1 h after (Post 1 h) and 24 h later (Post 24 h). Leukocyte profile and venous blood markers of muscle damage (creatine kinase (CK) and lactate dehydrogenase (LDH)) were also measured Pre-exercise, Post 1 h and Post 24 h. A significant time effect was observed to indicate a reduction in performance (Pre-exercise vs. Post-exercise) following the exercise bout in all conditions (P < 0.05). Indeed, at 1 h post exercise, a significant improvement in MVC and P(30 s) was respectively observed in the CWI and CWT groups compared to pre-exercise. Further, for the CWI group, this result was associated with a comparative blunting of the rise in total number of leucocytes at 1 h post and of plasma concentration of CK at 24 h post. The results indicate that the practice of cold water immersion and contrast water therapy are more effective immersion modalities to promote a faster acute recovery of maximal anaerobic performances (MVC and 30? all-out respectively) after an intermittent exhaustive exercise. These results may be explained by the suppression of plasma concentrations of markers of inflammation and damage, suggesting reduced passive leakage from disrupted skeletal muscle, which may result in the increase in force production during ensuing bouts of exercise.
Related JoVE Video
Effects of mode and intensity on the acute exercise-induced IL-6 and CRP responses in a sedentary, overweight population.
Eur. J. Appl. Physiol.
PUBLISHED: 11-01-2010
Show Abstract
Hide Abstract
This study sought to compare the respective effects of resistance or aerobic exercise of higher or lower intensities on the acute plasma interleukin-6 (IL-6) and C-reactive protein (CRP) response in a sedentary, middle-aged, disease-free cohort. Following baseline testing, and in a randomized cross-over design, 12 sedentary males completed four exercise protocols, including 40 min of moderate-vigorous (M-VA) or low-intensity (LA) aerobic exercise on a cycle ergometer; and a moderate-vigorous (M-VR) or low-intensity (LR) full-body resistance session matched for protocol duration. Venous blood was obtained pre-, post-, 3 h post and 24 h post-exercise and analysed for IL-6, CRP, leukocyte count, myoglobin, creatine kinase (CK), and cortisol. Diet and physical activity were standardized 24 h before and after exercise. Results indicated an elevated CRP response in the M-VR protocol in comparison to the low-intensity protocols (P < 0.05); however, no changes were evident between the moderate-vigorous intensity protocols. The moderate-vigorous intensity protocols induced significant increases of IL-6, cortisol, and leukocytes in comparison to the low-intensity protocols (P < 0.05). However, the IL-6 response showed no significant differences between the moderate-vigorous intensity protocols, despite the M-VR protocol inducing the largest response of markers indicative of muscle damage (CK, myoglobin, and neutrophil count) (P < 0.05). Hence, indicating a disassociation between the IL-6 response and markers of muscle damage within the respective exercise bouts. The highest IL-6 response was evident in the moderate-vigorous intensity protocols immediately post-exercise. Moreover, the exercise modality did not seem to influence the acute IL-6 and CRP response, with the main determinant of the IL-6 response being exercise intensity.
Related JoVE Video
Effects of acute multinutrient supplementation on rugby union game performance and recovery.
Int J Sports Physiol Perform
PUBLISHED: 03-24-2010
Show Abstract
Hide Abstract
To investigate the effects of an acute multinutrient supplement on game-based running performance, peak power output, anaerobic by-products, hormonal profiles, markers of muscle damage, and perceived muscular soreness before, immediately after, and 24 h following competitive rugby union games.
Related JoVE Video
Effects of resistance or aerobic exercise training on interleukin-6, C-reactive protein, and body composition.
Med Sci Sports Exerc
PUBLISHED: 01-20-2010
Show Abstract
Hide Abstract
To determine the effects of 10 wk of resistance or aerobic exercise training on interleukin-6 (IL-6) and C-reactive protein (CRP). Further, to determine pretraining and posttraining associations between alterations of IL-6 and CRP and alterations of total body fat mass (TB-FM), intra-abdominal fat mass (IA-FM), and total body lean mass (TB-LM).
Related JoVE Video
The effects of fluid ingestion on free-paced intermittent-sprint performance and pacing strategies in the heat.
J Sports Sci
PUBLISHED: 01-16-2010
Show Abstract
Hide Abstract
The purpose of this study was to examine the effects of fluid ingestion on pacing strategies and performance during intermittent-sprint exercise in the heat. Nine male rugby players performed a habituation session and 2 x 50-min intermittent-sprint protocols at a temperature of 31 degrees C, either with or without fluid. Participants were informed of a third session (not performed) to ensure that they remained blind to all respective conditions. The protocol consisted of a 15-m sprint every minute separated by self-paced bouts of hard running, jogging, and walking for the remainder of the minute. Sprint time, distance covered during self-paced exercise, and vertical jump height before and after exercise were recorded. Heart rate, core temperature, nude mass, capillary blood haematocrit, pH, lactate concentration, perceptual ratings of perceived exertion, thermal stress, and thirst were also recorded. Sprint times (fluid vs. no-fluid: 2.82 +/- 0.11 vs. 2.82 +/- 0.14) and distance covered during self-paced exercise (fluid vs. no-fluid: 4168 +/- 419 vs. 3981 +/- 263 m) were not different between conditions (P = 0.10-0.98) but were progressively reduced to a greater extent in the no-fluid trial (7 +/- 13%) (d = 0.56-0.58). There were no differences (P = 0.22-1.00; d = <0.20-0.84) between conditions in any physiological measures. Perceptual ratings of perceived exertion and thermal stress did not differ between conditions (P = 0.34-0.91; d < or =0.20-0.48). Rating of thirst after exercise was lower in the fluid trial (P = 0.02; d = 0.62-0.73). The present results suggest that fluid availability did not improve intermittent-sprint performance, however did affect pacing strategies with a greater reduction in distance covered of self-paced exercise during the no-fluid trial.
Related JoVE Video
The use of mixed-method, part-body pre-cooling procedures for team-sport athletes training in the heat.
J Strength Cond Res
PUBLISHED: 11-14-2009
Show Abstract
Hide Abstract
The current study investigated the effects of a pre-cooling intervention on physiological and performance responses to team-sport training in the heat. Seven male lacrosse players performed a familiarization session and 2 randomized, counterbalanced sessions consisting of a 30-minute intermittent-sprint conditioning session. Prior to the sessions, players performed a 20-minute mixed-method, part-body cooling intervention (consisting of cooling vests, cold towels to the neck, and ice packs to the quadriceps) or no cooling intervention. Performance was determined from collection of 1 Hz global positioning system (GPS) data and analyzed for distance and speed. Prior to, during, and following the sessions, core temperature, heart rate, rating of perceived exertion (RPE), and thermal sensation scale (TSS) were measured; additionally, a venous blood sample was collected before and after each session for measurement of interleukin-6 (IL-6), insulin-like growth factor (IGF-1) and insulin-like growth factor-binding protein3 (IGF-BP3). Results indicated that a greater distance was covered during the pre-cooling condition (3.35 +/- 0.20 vs. 3.11 +/- 0.13 km; p = 0.05). Further, most of this improvement was evident from a greater distance covered during moderate intensities of 7 to 14 km/h (2.28 +/- 0.18 vs. 2.00 +/- 0.24 km; p = 0.05). Peak speeds and very-high-intensity efforts (20 km/h +/-) were not different between conditions (p > 0.05). The increase in core temperature was blunted following cooling, with a lower core temperature throughout the cooling session (38.8 +/- 0.3 vs. 39.3 +/- 0.4 degrees C; p < 0.05). However, there were no differences in heart rate, RPE, TSS, IL-6, IGF-1, or IGF-BP3 between conditions (p > 0.05). Accordingly, the use of a mixed-method, part-body cooling intervention prior to an intermittent-sprint training session in the heat can assist in reducing thermoregulatory load and improve aspects of training performance for team sports.
Related JoVE Video
The effects of recovery interventions on consecutive days of intermittent sprint exercise.
J Strength Cond Res
PUBLISHED: 08-14-2009
Show Abstract
Hide Abstract
The purpose of this study was to compare four recovery interventions following simulated team sport, intermittent-sprint exercise on consecutive days. Ten female netball players performed four randomized sessions of a simulated netball exercise circuit on consecutive days. Each condition consisted of two identical sessions (Session 1 and 2), with the recovery intervention implemented at the completion of Session 1. Participants performed all interventions involving: passive recovery, active recovery (ACT), cold water immersion (CWI) and contrast water therapy (C(T)WT). No significant differences (p > 0.05) were evident between conditions for exercise performance (vertical jump, 20-m sprint, 10-m sprint, total circuit time) during Session 2. Effect size data indicated trends for an ameliorated decline in 5 x 20-m sprints and vertical jump for C(T)WT and CWI, respectively. C(T)WT demonstrated a significant reduction (p = 0.04) in lactate post-intervention compared to ACT recovery. Further, ACT recovery resulted in a significantly elevated (p < 0.01) heart rate compared to all other conditions postintervention and demonstrated significantly higher (p < 0.01) rating of perceived exertion postintervention and muscle soreness pre-exercise Session 2. It is likely that while interventions may be applicable to team sport practices, the 24-hour recovery period between exercise bouts was sufficient to allow performance to be maintained, regardless of recovery interventions.
Related JoVE Video
Core temperature responses and match running performance during intermittent-sprint exercise competition in warm conditions.
J Strength Cond Res
PUBLISHED: 07-02-2009
Show Abstract
Hide Abstract
This study investigated the thermoregulatory responses and match running performance of elite team sport competitors (Australian Rules football) during preseason games in a warm environment. During 2 games in dry bulb temperatures above 29 degrees C (>27 degrees C wet bulb globe temperature), 10 players were monitored for core temperature (Tcore) via a telemetric capsule, in-game motion patterns, blood lactate ([La]), body mass changes, urine specific gravity, and pre- and postgame vertical jump performance. The results showed that peak Tcore was achieved during the final quarter at 39.3 +/- 0.7 degrees C and that several players reached values near 40.0 degrees C. Further, the largest proportion of the total rise in Tcore (2.1 +/- 0.7 degrees C) occurred during the first quarter of the match, with only small increases during the remainder of the game. The game distance covered was 9.4 +/- 1.5 km, of which 2.7 +/- 0.9 km was at high-intensity speeds (>14.4 km x h(-1)). The rise in Tcore was correlated with first-quarter high-intensity running velocity (r = 0.72) and moderate-intensity velocity (r = 0.68), second-quarter Tcore and low-intensity activity velocity (r = -0.90), second-quarter Tcore and moderate-intensity velocity (r = 0.88), fourth-quarter rise in Tcore and very-high-intensity running distance (r = 0.70), and fourth-quarter Tcore and moderate-intensity velocity (r = 0.73). Additional results included mean game [La-] values of 8.7 +/- 0.1 mmol x L(-1), change in body mass of 2.1 +/- 0.8 kg, and no change (p > 0.05) in pre- to postgame vertical jump. These findings indicate that the plateau in Tcore may be regulated by the reduction in low-intensity activity and that pacing strategies may be employed during competitive team sports in the heat to ensure control of the internal heat load.
Related JoVE Video
Recovery of voluntary and evoked muscle performance following intermittent-sprint exercise in the heat.
Int J Sports Physiol Perform
PUBLISHED: 07-02-2009
Show Abstract
Hide Abstract
This study investigated the effects of hot conditions on the acute recovery of voluntary and evoked muscle performance and physiological responses following intermittent exercise.
Related JoVE Video
Physiological responses and bowling performance during repeated spells of medium-fast bowling.
J Sports Sci
PUBLISHED: 03-26-2009
Show Abstract
Hide Abstract
The aim of the present study was to investigate the relationship between physiological and performance responses during repeated 6-over fast-bowling spells. Six, first-class, medium-fast bowlers performed 2x6-over spells separated by 45 min of light activity. The 6-over spells were based on the Cricket Australia fast bowling skills test that is a set order of deliveries at a grid-based target. Ball speed, accuracy and full and final 5-m run-up speed were measured on each ball. Nude mass, heart rate, core temperature, capillary blood lactate, pH and glucose, perceptual measures of RPE and muscle soreness (MS) and repeated vertical jump efforts were measured prior to, during and following each spell. Results indicated no decrement (P=0.41) and small effect sizes (d<0.2) in bowling speed (125.7+/-5.1 and 125.4+/-4.5 km.h(-1)) or accuracy (40.4+/-16.1 and 41.6+/-18.0 AU) between spells 1 and 2. No differences (P=0.6-0.8) were present between spells for heart rate, core temperature, lactate, pH, glucose, RPE, MS or vertical jump. Only final 5-m run-up speed showed a large correlation with ball speed (r=0.70), while accuracy and speed were not correlated (r=0.05). In conclusion, repeated 6-over spells in well-trained bowlers results in minimal performance decrement in mild conditions (22 degrees C). As faster bowlers had faster final 5-m run-up speeds, the maintenance of high final 5-m run-up speeds might be important to maintaining bowling speed. Future research should also include a third bowling spell and warmer environmental conditions.
Related JoVE Video
Accuracy and reliability of GPS devices for measurement of movement patterns in confined spaces for court-based sports.
J Sci Med Sport
PUBLISHED: 02-18-2009
Show Abstract
Hide Abstract
The aim of this study was to assess the accuracy and reliability of global positioning system (GPS) measures of distance and speed, compared to a high-resolution motion analysis system, for confined movement patterns used in many court-based sports. A single male participant performed 10 repetitions of four respective drills replicating court-based movement patterns and six repetitions of a random movement drill that replicated tennis match-play movement patterns. Two 1Hz and two 5Hz GPS devices concurrently measured distance covered and speed of all court-based drills. A 22 camera VICON motion analysis system, operating at 100Hz, tracked the position of an 18mm reflective marker affixed to one of the GPS devices to provide the criterion movement data. Results indicated that both 1 and 5Hz GPS devices under reported distance covered as well as both mean and peak speed compared to the VICON system (P<0.05). The coefficient of variation for both GPS devices for distance and speed measures ranged between 4 and 25%. Further, the faster the speed and more repetitive the movement pattern (over a similar location), the greater the measurement error. The inter-unit reliability for distance and speed measures of both 1 and 5Hz systems for movements in confined spaces was generally low to moderate (r=0.10-0.70). In conclusion, for court-based sports or movements in confined spaces, GPS technology under reports distance covered and both mean and peak speed of movement.
Related JoVE Video
The effects of compression garments on recovery of muscle performance following high-intensity sprint and plyometric exercise.
J Sci Med Sport
PUBLISHED: 01-07-2009
Show Abstract
Hide Abstract
This study compared the effects of compression garments on recovery of evoked and voluntary performance following fatiguing exercise. Eleven participants performed 2 sessions separated by 7 days, with and without lower-body compression garments during and 24h post-exercise. Participants performed a 10-min exercise protocol of a 20-m sprint and 10 plyometric bounds every minute. Before, following, 2h and 24h post-exercise, evoked twitch properties of the knee extensors, peak concentric knee extension and flexion force were assessed, with blood samples drawn to measure lactate [La(-)], pH, creatine kinase (CK), aspartate transaminase (AST) and c-reactive protein (C-RP). Heart rate, exertion (RPE) and muscle soreness (MS) measures were obtained pre- and post-exercise. No differences (P=0.50-0.80) and small effect sizes (d<0.3) were present for 20-m sprint (3.59+/-0.22 vs. 3.59+/-0.18s) or bounding performance (17.13+/-1.4 vs. 17.21+/-1.7 m) in garment and control conditions. The decline and recovery in concentric force were not different (P=0.40) between conditions. Full recovery of voluntary performance was observed 2h post-exercise, however, evoked twitch properties remained suppressed 2h post-exercise in both conditions. No differences (P=0.40-0.80, d<0.3) were present between conditions for heart rate, RPE, [La(-)], pH, CK or C-RP. However, 24h post-exercise a smaller change (P=0.08; d=2.5) in AST (23.1+/-3.1 vs. 26.0+/-4.0) and reduced (P=0.01; d=1.1) MS (2.8+/-1.2 vs. 4.5+/-1.4) were present in the garments. In conclusion the effects of compression garments on voluntary performance and recovery were minimal; however, reduced levels of perceived MS were reported following recovery in the garments.
Related JoVE Video
The influence of field size, player number and rule changes on the physiological responses and movement demands of small-sided games for cricket training.
J Sports Sci
Show Abstract
Hide Abstract
This study investigated the physiological responses and movement demands associated with modified versions of small-sided games for cricket training, termed Battlezone. Eleven (22.2 ± 3.6 years; 1.80 ± 0.06 m; 81.7 ± 11.4 kg) male, cricket players volunteered to perform each of four modified 8-over scenarios of Battlezone. Modifications to Battlezone included reducing the field size, removal of a fielder, a combination of these modifications and additional rule changes. Heart rate, blood lactate concentration, rating of perceived exertion (RPE) and the movement patterns of participants were measured during each scenario. The total distances covered per 8-over bout ranged from 626 ± 335 m for wicketkeepers to 1795 ± 457 m for medium-fast bowlers; although similar distances (P > 0.05) were covered within positions between the four different scenarios. Between scenarios, the greatest mean speed, heart rate and blood lactate responses occurred when the rules were changed, resulting in increased movement patterns (P < 0.05), most notably for batsmen and wicketkeepers. In contrast, altering the playing field size or player number did not significantly influence (P > 0.05) these responses. These results suggest that the physical demands of cricket-specific training can be increased via rule variations including hit-and-run activities, more so than field size or player number.
Related JoVE Video
Battlezone: An examination of the physiological responses, movement demands and reproducibility of small-sided cricket games.
J Sports Sci
Show Abstract
Hide Abstract
As cricket training typically involves separate skill and conditioning sessions, this study reported on the movement demands, physiological responses and reproducibility of the demands of small-sided cricket games. Thirteen amateur, male cricket players (age: 22.8 ± 3.5 years, height: 1.78 ± 0.06 m, body mass: 78.6 ± 7.1 kg) completed two sessions of a generic small-sided cricket game, termed Battlezone; consisting of six repeat 8-over bouts. Heart rate and movement demands were continuously recorded, whilst blood lactate concentration and perceived exertion were recorded after each respective bout. Batsmen covered the greatest distance (1147 ± 175 m) and demonstrated the greatest mean movement speed (63 ± 9 m · min?¹) during each bout. The majority of time (65-86%) was spent with a heart rate of between 51-85% HR(max) and a blood lactate concentration of 1.1-2.0 mmol · L?¹. Rating of perceived exertion ranged between 4.2-6.0. Movement demands and physiological responses did not differ between standardised sessions within respective playing positions (P > 0.05). The reliability for the majority of movement demands and physiological responses were moderate to high (CV: 5-17%; ICC: 0.48-1.00) within all playing positions. These results suggest that the physiological responses and movement characteristics of generic small-sided cricket games were consistent between sessions within respective playing positions.
Related JoVE Video
Beneficial effects of 12 weeks of aerobic compared with resistance exercise training on perceived appetite in previously sedentary overweight and obese men.
Metab. Clin. Exp.
Show Abstract
Hide Abstract
To investigate the effect of 12 weeks of aerobic (AER) compared with resistance training (RES) on perceived hunger and fullness, together with appetite-related hormones in both the fasted state and postprandially.
Related JoVE Video
Effects of mixed-method cooling on recovery of medium-fast bowling performance in hot conditions on consecutive days.
J Sports Sci
Show Abstract
Hide Abstract
This investigation examined physiological and performance effects of cooling on recovery of medium-fast bowlers in the heat. Eight, medium-fast bowlers completed two randomised trials, involving two sessions completed on consecutive days (Session 1: 10-overs and Session 2: 4-overs) in 31 ± 3°C and 55 ± 17% relative humidity. Recovery interventions were administered for 20 min (mixed-method cooling vs. control) after Session 1. Measures included bowling performance (ball speed, accuracy, run-up speeds), physical demands (global positioning system, counter-movement jump), physiological (heart rate, core temperature, skin temperature, sweat loss), biochemical (creatine kinase, C-reactive protein) and perceptual variables (perceived exertion, thermal sensation, muscle soreness). Mean ball speed was higher after cooling in Session 2 (118.9 ± 8.1 vs. 115.5 ± 8.6 km · h?¹; P = 0.001; d = 0.67), reducing declines in ball speed between sessions (0.24 vs. -3.18 km · h?¹; P = 0.03; d = 1.80). Large effects indicated higher accuracy in Session 2 after cooling (46.0 ± 11.2 vs. 39.4 ± 8.6 arbitrary units [AU]; P = 0.13; d = 0.93) without affecting total run-up speed (19.0 ± 3.1 vs. 19.0 ± 2.5 km · h?¹; P = 0.97; d = 0.01). Cooling reduced core temperature, skin temperature and thermal sensation throughout the intervention (P = 0.001-0.05; d = 1.31-5.78) and attenuated creatine kinase (P = 0.04; d = 0.56) and muscle soreness at 24-h (P = 0.03; d = 2.05). Accordingly, mixed-method cooling can reduce thermal strain after a 10-over spell and improve markers of muscular damage and discomfort alongside maintained medium-fast bowling performance on consecutive days in hot conditions.
Related JoVE Video
Postexercise cooling interventions and the effects on exercise-induced heat stress in a temperate environment.
Appl Physiol Nutr Metab
Show Abstract
Hide Abstract
The aim of this study was to examine the effects of cool water immersion (20 °C; CWI) while wearing a cooling jacket (Cryovest;V) and a passive control (PAS) as recovery methods on physiological and thermoregulatory responses between 2 exercise bouts in temperate conditions. Nine well-trained male cyclists performed 2 successive bouts of 45 min of endurance cycling exercise in a temperate environment (20 °C) separated by 25 min of the respective recovery interventions. Capillary blood samples were obtained to measure lactate (La?), sodium (Na?), bicarbonate (HCO??) concentrations and pH, whilst body mass loss (BML), core temperature (T(core)), skin temperature (T(skin)), heart rate (HR), oxygen uptake , and minute ventilation were measured before (Pre), immediately after the first exercise bout (Ex1), the recovery (R), and after the second exercise bout (Ex2). V and CWI both resulted in a reduction of T(skin) at R (-2.1 ± 0.01 °C and -11.6 ± 0.01 °C, respectively, p < 0.01). Despite no difference in final values post-Ex2 (p > 0.05), V attenuated the rise in HR, minute ventilation, and oxygen uptake from Ex1 to Ex2, while T(core) and T(skin) were significantly lower following the second session (p < 0.05). Further, CWI was also beneficial in lowering T(core), T(skin), and BML, while a rise in Na? was observed following Ex2 (p < 0.05). Overall results indicate that cooling interventions (V and CWI) following exercise in a temperate environment provide a reduction in thermal strain during ensuing exercise bouts.
Related JoVE Video
Hydration, sweat and thermoregulatory responses to professional football training in the heat.
J Sports Sci
Show Abstract
Hide Abstract
AbstThis study examined the relationship between intensity of training and changes in hydration status, core temperature, sweat rate and composition and fluid balance in professional football players training in the heat. Thirteen professional football players completed three training sessions; "higher-intensity" (140 min; HI140), "lower-intensity" (120 min; LI120) and "game-simulation" (100 min; GS100). Movement demands were measured by Global Positioning System, sweat rate and concentration were determined from dermal patches and body mass change. Despite similar environmental conditions (26.9 ± 0.1 °C and 65.0 ± 7.0% relative humidity [Rh]), higher relative speeds (m · min(-1)) and increased perceptions of effort and thermal strain were observed in HI140 and GS100 compared with LI120 (P < 0.05). Significantly (P < 0.05) greater sweat rate (L · h(-1)) and electrolyte losses (g) were observed in HI140 and GS100 compared with LI120. Rate of rise in core temperature was correlated with mean speed (r = 0.85), session rating of perceived exertion (sRPE) (r = 0.61), loss of potassium (K+) (r = 0.51) sweat rate (r = 0.49), and total sweat loss (r = 0.53), with mean speed the strongest predictor. Sodium (Na+) (r = 0.39) and K+ (r = 0.50) losses were associated with total distance covered. In hot conditions, individualised rehydration practices should be adopted following football training to account for differences in sweat rate and electrolyte losses in response to intensity and overall activity within a session.
Related JoVE Video
Mixed-method pre-cooling reduces physiological demand without improving performance of medium-fast bowling in the heat.
J Sports Sci
Show Abstract
Hide Abstract
This study examined physiological and performance effects of pre-cooling on medium-fast bowling in the heat. Ten, medium-fast bowlers completed two randomised trials involving either cooling (mixed-methods) or control (no cooling) interventions before a 6-over bowling spell in 31.9±2.1°C and 63.5±9.3% relative humidity. Measures included bowling performance (ball speed, accuracy and run-up speeds), physical characteristics (global positioning system monitoring and counter-movement jump height), physiological (heart rate, core temperature, skin temperature and sweat loss), biochemical (serum concentrations of damage, stress and inflammation) and perceptual variables (perceived exertion and thermal sensation). Mean ball speed (114.5±7.1 vs. 114.1±7.2 km · h(-1); P = 0.63; d = 0.09), accuracy (43.1±10.6 vs. 44.2±12.5 AU; P = 0.76; d = 0.14) and total run-up speed (19.1±4.1 vs. 19.3±3.8 km · h(-1); P = 0.66; d = 0.06) did not differ between pre-cooling and control respectively; however 20-m sprint speed between overs was 5.9±7.3% greater at Over 4 after pre-cooling (P = 0.03; d = 0.75). Pre-cooling reduced skin temperature after the intervention period (P = 0.006; d = 2.28), core temperature and pre-over heart rates throughout (P = 0.01-0.04; d = 0.96-1.74) and sweat loss by 0.4±0.3 kg (P = 0.01; d = 0.34). Mean rating of perceived exertion and thermal sensation were lower during pre-cooling trials (P = 0.004-0.03; d = 0.77-3.13). Despite no observed improvement in bowling performance, pre-cooling maintained between-over sprint speeds and blunted physiological and perceptual demands to ease the thermoregulatory demands of medium-fast bowling in hot conditions.
Related JoVE Video
Concurrent resistance and aerobic exercise stimulates both myofibrillar and mitochondrial protein synthesis in sedentary middle-aged men.
J. Appl. Physiol.
Show Abstract
Hide Abstract
We determined myofibrillar and mitochondrial protein fractional synthesis rates (FSR), intramuscular signaling protein phosphorylation, and mRNA expression responses after isolated bouts of resistance exercise (RE), aerobic exercise (AE), or in combination [termed concurrent exercise (CE)] in sedentary middle-aged men. Eight subjects (age = 53.3 ± 1.8 yr; body mass index = 29.4 ± 1.4 kg·m(2)) randomly completed 8 × 8 leg extension repetitions at 70% of one repetition-maximum, 40 min of cycling at 55% peak aerobic power output (AE), or (consecutively) 50% of the RE and AE trials (CE). Biopsies were obtained (during a primed, constant infusion of l-[ring-(13)C(6)]phenylalanine) while fasted, and at 1 and 4 h following postexercise ingestion of 20 g of protein. All trials increased mitochondrial FSR above fasted rates (RE = 1.3-fold; AE = 1.5; CE = 1.4; P < 0.05), although only CE (2.2) and RE (1.8) increased myofibrillar FSR (P < 0.05). At 1 h postexercise, phosphorylation of Akt on Ser(473) (CE = 7.7; RE = 4.6) and Thr(308) (CE = 4.4; RE = 2.9), and PRAS40 on Thr(246) (CE = 3.8; AE = 2.5) increased (P < 0.05), with CE greater than AE for Akt Ser(473)-Thr(308) and greater than RE for PRAS40 (P < 0.05). Despite increased phosphorylation of Akt-PRAS40, phosphorylation of mammalian target of rapamycin (Ser(2448)) remained unchanged (P > 0.05), while rpS6 (Ser(235/236)) increased only in RE (10.4) (P < 0.05). CE and AE both resulted in increased peroxisome proliferator receptor-? coactivator 1-? (PGC1?) expression at 1 h (CE = 2.9; AE = 2.8; P < 0.05) and 4 h (CE = 2.6; AE = 2.4) and PGC1? expression at 4 h (CE = 2.1; AE = 2.6; P < 0.05). These data suggest that CE-induced acute stimulation of myofibrillar and mitochondrial FSR, protein signaling, and mRNA expression are equivalent to either isolate mode (RE or AE). These results occurred without an interference effect on muscle protein subfractional synthesis rates, protein signaling, or mRNA expression.
Related JoVE Video
Effects of resistance or aerobic exercise training on total and regional body composition in sedentary overweight middle-aged adults.
Appl Physiol Nutr Metab
Show Abstract
Hide Abstract
The purpose of this study was to examine the effects of 10 weeks of aerobic endurance training (AET), resistance exercise training (RET), or a control (CON) condition on absolute and relative fat mass (FM) or fat-free mass (FFM) in the total body (TB) and regions of interest (ROIs) of sedentary overweight middle-aged males and females. Following prescreening, 102 subjects underwent anthropometric measurements, dual-energy X-ray absorptiometry, and strength and aerobic exercise testing. Randomized subjects (male RET, n = 16; female RET, n = 19; male AET, n = 16; and female AET, n = 25) completed supervised and periodized exercise programs (AET, 30-50 min cycling at 70%-75% maximal heart rate; RET, 2-4 sets × 8-10 repetitions of 5-7 exercises at 70%-75% 1 repetition maximum) or a nonexercising control condition (male CON, n = 13 and female CON, n = 13). Changes in absolute and relative TB-FM and TB-FFM and ROI-FM and ROI-FFM were determined. At baseline, and although matched for age and body mass index, males had greater strength, aerobic fitness, body mass, absolute and relative TB-FFM and ROI-FFM, but reduced absolute and relative TB-FM and ROI-FM, compared with females (p < 0.05). After training, both female exercise groups showed equivalent or greater relative improvements in strength and aerobic fitness than did the male exercise groups (p < 0.05); however, the male exercise groups increased TB-FFM and reduced TB-FM more than did the female exercise groups (p < 0.05). Male AET altered absolute FM more than male RET altered absolute FFM, thus resulting in a greater enhancement of relative FFM. Despite equivalent or greater responses to RET or AET by female subjects, the corresponding respective increases in FFM or reductions in FM were lower than those in males, indicating that a biased dose-response relationship exists between sexes following 10 weeks of exercise training.
Related JoVE Video
The acute effects of aerobic exercise and modified rugby on inflammation and glucose homeostasis within Indigenous Australians.
Eur. J. Appl. Physiol.
Show Abstract
Hide Abstract
This study investigated the acute effects of two exercise modes, including cycle ergometry and modified rugby on inflammation and glucose regulation within an Indigenous Australian population. Ten sedentary, untrained Indigenous male participants volunteered to participate and were not clinically diagnosed with cardiovascular or metabolic disorders. Following baseline testing and in a randomized cross-over design participants completed two exercise protocols (cycle ergometry and modified rugby) of 40-min duration separated by 7 days recovery. Fasting venous blood was collected pre, post, 30, 60 and 240 min post exercise for analysis of glucose, insulin, cortisol and inflammatory markers of tumour necrosis factor (TNF)-?, interleukin (IL)-1?, IL-6, IL-1 receptor agonist (ra) and C-reactive protein (CRP). IL-6 and IL-1ra were significantly (P < 0.05) increased within the 240 min post-exercise period, without significant differences between protocols (P > 0.05). There were no significant changes within or between protocols for TNF-?, IL-1? and CRP (P > 0.05). A comparison of insulin resistance: homeostasis model (HOMA) between resting and 240 min post exercise shows a change from a baseline value of 4.44 (3.71) to 1.76 (1.67) HOMA in cycle ergometry (P < 0.05) and to 1.54 (1.33) HOMA in modified rugby (P < 0.05), without differences between sessions (P > 0.05). This study identified similar acute inflammatory and glucose regulatory responses between cycle ergometry and modified rugby. Prescribing modified rugby as a mode of physical activity may provide Indigenous populations with a community-based approach to promote increased engagement in physical activity and assist in the acute regulation of glucose disposal and inflammatory cytokines.
Related JoVE Video
Duration-dependant response of mixed-method pre-cooling for intermittent-sprint exercise in the heat.
Eur. J. Appl. Physiol.
Show Abstract
Hide Abstract
This study examined the effects of pre-cooling duration on performance and neuromuscular function for self-paced intermittent-sprint shuttle running in the heat. Eight male, team-sport athletes completed two 35-min bouts of intermittent-sprint shuttle running separated by a 15-min recovery on three separate occasions (33°C, 34% relative humidity). Mixed-method pre-cooling was completed for 20 min (COOL20), 10-min (COOL10) or no cooling (CONT) and reapplied for 5-min mid-exercise. Performance was assessed via sprint times, percentage decline and shuttle-running distance covered. Maximal voluntary contractions (MVC), voluntary activation (VA) and evoked twitch properties were recorded pre- and post-intervention and mid- and post-exercise. Core temperature (T (c)), skin temperature, heart rate, capillary blood metabolites, sweat losses, perceptual exertion and thermal stress were monitored throughout. Venous blood draws pre- and post-exercise were analyzed for muscle damage and inflammation markers. Shuttle-running distances covered were increased 5.2 ± 3.3% following COOL20 (P < 0.05), with no differences observed between COOL10 and CONT (P > 0.05). COOL20 aided in the maintenance of mid- and post-exercise MVC (P < 0.05; d > 0.80), despite no conditional differences in VA (P > 0.05). Pre-exercise T (c) was reduced by 0.15 ± 0.13°C with COOL20 (P < 0.05; d > 1.10), and remained lower throughout both COOL20 and COOL10 compared to CONT (P < 0.05; d > 0.80). Pre-cooling reduced sweat losses by 0.4 ± 0.3 kg (P < 0.02; d > 1.15), with COOL20 0.2 ± 0.4 kg less than COOL10 (P = 0.19; d = 1.01). Increased pre-cooling duration lowered physiological demands during exercise heat stress and facilitated the maintenance of self-paced intermittent-sprint performance in the heat. Importantly, the dose-response interaction of pre-cooling and sustained neuromuscular responses may explain the improved exercise performance in hot conditions.
Related JoVE Video
Accuracy and reliability of GPS devices for measurement of sports-specific movement patterns related to cricket, tennis and field-based team sports.
J Strength Cond Res
Show Abstract
Hide Abstract
The aim of this study was to determine the accuracy and reliability of 5, 10 and 15 Hz global positioning system (GPS) devices. Two male subjects (age: 25.5 ± 0.7 yr; height: 1.75 ± 0.01 m; body mass: 74 ± 5.7 kg) completed ten repetitions of drills replicating movements typical of tennis, cricket and field-based (football) sports. All movements were completed wearing two 5 Hz and 10 Hz MinimaxX and two GPS-Sports 15 Hz GPS devices in a specially designed harness. Criterion movement data for distance and speed was provided from a 22-camera VICON system sampling at 100 Hz. Accuracy was determined using one-way analysis of variance with Tukeys post-hoc tests. Inter-unit reliability was determined using intra-class correlation (ICC) and typical error was estimated as coefficient of variation (CV). Overall, for the majority of distance and speed measures as measured using the 5, 10 and 15 Hz GPS devices, were not significantly different (p>0.05) to the VICON data. Additionally, no improvements in the accuracy or reliability of GPS devices were observed with an increase in the sampling rate. However, the CV for the 5 and 15 Hz devices for distance and speed measures ranged between 3-33%, with increasing variability evident in higher speed zones. The majority of ICC measures possessed a low level of inter-unit reliability (r=-0.35-0.39). Based on these results, practitioners of these devices should be aware that measurements of distance and speed may be consistently underestimated, regardless of the movements performed.
Related JoVE Video
Evidence of Disturbed Sleep and Increased Illness in Overreached Endurance Athletes.
Med Sci Sports Exerc
Show Abstract
Hide Abstract
To examine whether i) objective markers of sleep quantity and quality are altered in endurance athletes experiencing overreaching in response to an overload training program and ii) whether potential reduced sleep quality would be accompanied with higher prevalence of upper respiratory tract infections in this population.
Related JoVE Video

What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

How does it work?

We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

Video X seems to be unrelated to Abstract Y...

In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.