Translate this page to:
Arabic
In JoVE (1)
Other Publications (23)
- American Journal of Physical Medicine & Rehabilitation / Association of Academic Physiatrists
- Clinics in Sports Medicine
- Journal of Athletic Training
- Journal of Sports Sciences
- Medicine and Science in Sports and Exercise
- Journal of Athletic Training
- Clinical Biomechanics (Bristol, Avon)
- Journal of Sport Rehabilitation
- Clinical Rehabilitation
- American Journal of Physical Medicine & Rehabilitation / Association of Academic Physiatrists
- Journal of Athletic Training
- North American Journal of Sports Physical Therapy : NAJSPT
- Journal of Athletic Training
- Journal of Sport Rehabilitation
- Journal of Athletic Training
- Journal of Strength and Conditioning Research / National Strength & Conditioning Association
- The Journal of Orthopaedic and Sports Physical Therapy
- PM & R : the Journal of Injury, Function, and Rehabilitation
- Journal of Electromyography and Kinesiology : Official Journal of the International Society of Electrophysiological Kinesiology
- Journal of Strength and Conditioning Research / National Strength & Conditioning Association
- Journal of Sports Sciences
- Clinical Rehabilitation
- Environmental Science & Technology
Automatic Translation
This translation into Arabic was automatically generated.
English Version | Other Languages
Articles by Kathryn M. Pietrosimone in JoVE
JoVE General
قياس من الانجذاب الكيميائي الخلوي مع ECIS / سيارات الأجرة
1Molecular and Cell Biology, University of Connecticut, 2University of Connecticut
نظام ECIS / سيارات الأجرة هو الآلي، في الوقت الحقيقي فحص الكيميائي الذي يقيس الخلوية. في هذا الاختبار، وخلايا تتحرك تحت طبقة من الاغاروز للوصول إلى القطب الهدف. ويتم قياس حركة الخليوي عن ظهور المقاومة إلى 0 ميلان الحالي.
Other articles by Kathryn M. Pietrosimone on PubMed
Joint Angle and Contraction Mode Influence Quadriceps Motor Neuron Pool Excitability
The purpose of the study was to compare the central activation ratio (CAR) of eccentric contractions to isometric contractions at 30 and 70 degrees of knee flexion.
Neuromuscular Consequences of Anterior Cruciate Ligament Injury
The neuromuscular consequences of anterior cruciate ligament (ACL) injury are important considerations because these deficits play a crucial role in a patient's recovery following ACL injury or reconstruction. The purpose of this article is to review and synthesize the known neuromuscular consequences of ACL injury and reconstruction. Specifically, changes in somatosensation, muscle activation, muscle strength, atrophy, balance, biomechanics, and patient-oriented outcomes are discussed. Understanding neuromuscular consequences aids in the construction of optimized rehabilitation strategies.
A Systematic Review of Prophylactic Braces in the Prevention of Knee Ligament Injuries in Collegiate Football Players
To determine the relative risk reduction associated with prophylactic knee braces in the prevention of knee injuries in collegiate football players.
Focal Knee Joint Cooling Increases the Quadriceps Central Activation Ratio
The objective of this study was to evaluate the effects of a 20-min focal knee joint cooling intervention on quadriceps central activation ratio (CAR) in healthy volunteers. A counterbalanced, cross-over study assessed the effects of a focal joint cooling intervention compared with a control condition 3-14 days apart. Eleven healthy volunteers (6 males, 5 females; age 25 +/- 5 years; height 1.71 +/- 0.1 m, mass 77 +/- 21 kg) were included in the final analysis. The joint cooling intervention consisted of two 1.5-litre ice bags applied to the knee joint for 20 min, in one of two counterbalanced sessions, completed 3-14 days apart. In the control session, participants sat quietly between the baseline and 20-min measurements. Quadriceps CAR was assessed at 70 degrees of knee flexion at four instants (baseline, 20, 30, and 45 min). There was a significant treatment x time interaction (F(3,30) = 5.9, P = 0.003) and post hoc analyses revealed that CAR was higher in the focal knee joint cooling session than the control session at 20 min (0.79 +/- 0.12 vs. 0.70 +/- 0.12; t(10) = 3.9, P = 0.003) and 45 min (0.77 +/- 0.10 vs. 0.69 +/- 0.12; t(10) = 3.1, P = 0.01). The CAR tended to be higher during the experimental session than the control session at 30 min (0.79 +/- 0.13 vs. 0.74 +/- 0.11; t(10) = 2.1, P = 0.07).Volitional activation increased following focal knee joint cooling in healthy volunteers.
Immediate Effects of Transcutaneous Electrical Nerve Stimulation and Focal Knee Joint Cooling on Quadriceps Activation
To determine whether transcutaneous electrical nerve stimulation (TENS) and focal knee joint cooling will affect the quadriceps central activation ratio (CAR) in patients with tibiofemoral osteoarthritis.
Quadriceps Activation Following Knee Injuries: a Systematic Review
Arthrogenic muscle inhibition is an important underlying factor in persistent quadriceps muscle weakness after knee injury or surgery.
Sagittal Plane Knee Joint Moments Following Anterior Cruciate Ligament Injury and Reconstruction: a Systematic Review
Gait adaptations in persons with anterior cruciate ligament (ACL) injuries have been debated. Many studies examine high speed, 3-dimensional video gait analysis to compare knee joint torques during simulated activities of daily living.
Effects of Menthol-based Counterirritant on Quadriceps Motoneuron-pool Excitability
Motoneuron-pool facilitation after cryotherapy may be mediated by stimulation of thermoreceptors surrounding a joint. It is unknown whether menthol counterirritants, which also stimulate thermoreceptors, have the same effect on motoneuron-pool excitability (MNPE).
Effects of Disinhibitory Transcutaneous Electrical Nerve Stimulation and Therapeutic Exercise on Sagittal Plane Peak Knee Kinematics and Kinetics in People with Knee Osteoarthritis During Gait: a Randomized Controlled Trial
to determine whether sensory transcutaneous electrical nerve stimulation (TENS) augmented with therapeutic exercise and worn for daily activities for four weeks would alter peak gait kinetics and kinematics, compared with placebo electrical stimulation and exercise, and exercise only.
Relationship Between Transcranial Magnetic Stimulation and Percutaneous Electrical Stimulation in Determining the Quadriceps Central Activation Ratio
To determine the relationship between quadriceps central activation ratios (CARs) derived from a percutaneous electrical stimulation (CAR(SIB)) and a transcranial magnetic stimulation (CAR(TMS)) in healthy participants.
Transcranial Magnetic Stimulation and Volitional Quadriceps Activation
Quadriceps-activation deficits have been reported after meniscectomy. Transcranial magnetic stimulation (TMS) in conjunction with maximal contractions affects quadriceps activation in patients after meniscectomy.
Contralateral Effects of Disinhibitory Tens on Quadriceps Function in People with Knee Osteoarthritis Following Unilateral Treatment
Quadriceps activation failure is common in patients with tibiofemoral osteoarthritis (TFOA) and has been reported to occur bilaterally following acute and chronic knee injuries. Sensory transcutaneous electrical stimulation (TENS) applied to the knee has increased ipsilateral quadriceps activation, yet it remains unknown if repeated sensory TENS treatments affect activation in the contralateral quadriceps.
Motor-neuron Pool Excitability of the Lower Leg Muscles After Acute Lateral Ankle Sprain
Neuromuscular deficits in leg muscles that are associated with arthrogenic muscle inhibition have been reported in people with chronic ankle instability, yet whether these neuromuscular alterations are present in individuals with acute sprains is unknown.
Effects of Arthroscopic Partial Meniscectomy on Quadriceps Strength: A Systematic Review
CONTEXT: Arthroscopic partial meniscectomy (APM) following meniscal tear has been widely accepted and associated with quick return to activity. Unfortunately, meniscectomy is associated with risk for knee osteoarthritis, which may be attributed to post-surgical quadriceps weakness. This has important implications as the quadriceps play a prominent role in knee stabilization and energy attenuation in the lower extremity. OBJECTIVE: To determine the magnitude of inter-limb quadriceps strength deficits in people with unilateral APM by systematically reviewing the current literature. EVIDENCE ACQUISITION: The Web of Knowledge databases were searched on September 22, 2010, using terms "meniscus" OR "meniscectomy" AND "quadriceps strength" OR "quadriceps weakness." Included articles were written in English, reporting means and standard deviations of isokinetic peak torque at 60 and 180 °/sec for both limbs. EVIDENCE SYNTHESIS: Four articles were included in the final analysis. Effect sizes and 95% confidence intervals (CI) were calculated between limbs for time periods less than 1 month, 1-3 months, 3-6 months, and greater than 6 months. CONCLUSION: Homogeneous effect sizes indicate quadriceps weakness in the involved limb. Effects were strong at less than 1 month (d= -1.01 to -1.62), while weak to strong effects were found between 1-3 months (d= -.40 to -8.04), and 3-6 months (d= -.40 to -5.11). Weak effects were found at greater than 6 months (d= -.30 to-.37). Definitive effects with a CI not crossing zero were found in 65% of the data. Although APM patients return to function within weeks following surgery, prolonged quadriceps strength deficits may increase the risk of knee joint degeneration. Furthermore, evidence of bilateral dysfunction following unilateral injury may suggest neuromuscular deficits post APM are greater than the inter-limb differences found in this review. Further research should be conducted to determine the nature of strength deficits and the best methods for restoring strength following APM.
Subcutaneous Thigh Fat Assessment: a Comparison of Skinfold Calipers and Ultrasound Imaging
Skinfold calipers (SC) typically are used to determine subcutaneous fat thicknesses. Identifying the exact separation of muscle and fat can complicate measurements. Ultrasound imaging (USI) might provide a better technique for analyzing subcutaneous fat thicknesses.
Sling Exercise and Traditional Warm-up Have Similar Effects on the Velocity and Accuracy of Throwing
Throwing is a complex motion that involves the entire body and often puts an inordinate amount of stress on the shoulder and the arm. Warm-up prepares the body for work and can enhance performance. Sling-based exercise (SE) has been theorized to activate muscles, particularly the stabilizers, in a manner beneficial for preactivity warm-up, yet this hypothesis has not been tested. Our purpose was to determine if a warm-up using SE would increase throwing velocity and accuracy compared to a traditional, thrower's 10 warm-up program. Division I baseball players (nonpitchers) (16 men, age: 19.6 ± 1.3, height: 184.2 ± 6.2 cm, mass: 76.9 ± 19.2 kg) volunteered to participate in this crossover study. All subjects underwent both a warm-up routine using a traditional method (Thrower's 10 exercises) and a warm-up routine using closed kinetic chain SE methods (RedCord) on different days separated by 72 hours. Ball velocity and accuracy measures were obtained on 10 throws after either the traditional and SE warm-up regimens. Velocity was recorded using a standard Juggs radar gun (JUGS; Tualatin, OR, USA). Accuracy was recorded using a custom accuracy target. An Analysis of covariance was performed, with the number of throws recorded before the testing was used as a covariate and p < 0.05 was set a priori. There were no statistical differences between the SE warm-up and Thrower's 10 warm-up for throwing velocity (SE: 74.7 ± 7.5 mph, Thrower's 10: 74.6 ± 7.3 mph p = 0.874) or accuracy (SE: 115.6 ± 53.7 cm, Thrower's 10: 91.8 ± 55 cm, p = 0.136). Warming up with SE produced equivalent throwing velocity and accuracy compared to the Thrower's 10 warm-up method. Thus, SE provides an alternative to traditional warm-up.
Effects of Transcutaneous Electrical Nerve Stimulation and Therapeutic Exercise on Quadriceps Activation in People with Tibiofemoral Osteoarthritis
Blinded, randomized controlled trial.
Voluntary Quadriceps Activation Deficits in Patients with Tibiofemoral Osteoarthritis: a Meta-analysis
The objective of this study was to assess the magnitude of quadriceps activation deficits in the involved extremity and contralateral extremity of patients with knee joint osteoarthritis (OA), as well as matched controls. An exhaustive search of the literature was performed using Web of Science between 1970 and February 24, 2010, using the search terms "osteoarthritis" AND "quadriceps activation" OR "quadriceps inhibition" and cross-referencing pertinent articles. Studies written in English reporting quadriceps activation means and standard deviations in patients with tibiofemoral OA via a method using an exogenous electrical stimulation were evaluated for methodological quality and were included for data analysis. Fourteen individual studies met the criteria for inclusion into data analysis. The number of participants and mean activation levels were used to calculate weighted means for the involved limb (14 studies), the contralateral limb (from a subset of 6 studies), and an involved limb subset from only the studies evaluating the contralateral limb and population of control subjects (5 studies). Weighted means from the involved limb (82.2; 95% CI = 81.4-83.3%), contralateral limb (81.7; 80.1-83.3%), and involved limb subset (76.8; 74.8-78.8%) groups were found to have lower volitional quadriceps activation compared with the control groups (90; 88.9-91.7%). Although the weighted involved limb mean was not different from that of the contralateral limb, the mean and 95% confidence intervals for the involved limb subset were lower than that of the contralateral limb group, suggesting that the involved limb had less volitional activation within OA subjects. This provides evidence that bilateral quadriceps volitional activation deficits are present in persons with knee OA.
Patellofemoral Pain Syndrome Alters Neuromuscular Control and Kinetics During Stair Ambulation
The aim of the study was to investigate differences in frontal plane knee kinetics, onset timing and duration of the gluteus medius (GMed), adductor longus (AL), and vastus medialis oblique (VMO) during stair ambulation between those with and without patellofemoral pain syndrome (PFPS). Twenty PFPS patients and twenty healthy participants completed stair ambulation while surface electromyography (EMG), video, and ground reaction forces were collected. PFPS patients had a higher peak internal knee abduction moment during stair ascent, and a higher internal knee abduction impulse for both ascent and descent. During stair ascent, PFPS patients displayed earlier onset of the AL and later onset of GMed, compared to the healthy individuals. Also, PFPS patients had longer activation duration of the AL and shorter activation durations of the VMO and GMed during stair ascent. During stair descent, PFPS patients displayed delayed GMed onset and shorter activation duration of GMed and VMO. The results of the study suggest that altered neuromuscular control of the medial thigh musculature may be an important contributor to PFPS.
Effects of Electromyographic Biofeedback on Quadriceps Strength: a Systematic Review
Quadriceps strength is a vital component to lower extremity function and is often the focus in resistance training interventions and injury rehabilitation. Electromyographic biofeedback (EMGBF) is frequently used to supplement strength gains; however, the true effect remains unknown. Therefore, the objective of this investigation was to determine the magnitude of the treatment effect for EMGBF on quadriceps strength compared with that of placebo and traditional exercise interventions in both healthy and pathological populations. Web of Science and ProQuest databases were searched, and bibliographies of relevant articles were crossreferenced. Six articles measuring isometric quadriceps strength in response to EMGBF training were included and methodologically assessed using the Physiotherapy Evidence Database (PEDro). Standardized effect sizes with 95% confidence intervals (CIs) were calculated from preintervention and postintervention measures for EMGBF, placebo, and exercise-only interventions. Separate comparisons were made between studies assessing different intervention length (<4 and ≥4 weeks) and patient populations (pathological and healthy). Articles included received an average PEDro score of 6.5 ± 0.84. Homogeneous EMGBF effect sizes were found in all 6 studies (d = 0.01-5.56), with 4 studies reporting CI that crossed 0. A heterogeneous collection of effect sizes was found for exercise alone (d = -0.12 to 1.18) and placebo (d = -0.2 to 1.38), with 4 and 1 studies having a CI that crossed 0, respectively. The greatest EMGBF effects were found in pathological populations (d = 0.01-5.56), with the strongest effect found in the subjects with knee osteoarthritis (d = 5.56, CI = 4.26-6.68). As a group, effects were the strongest for EMGBF compared with that of placebo and exercise-only interventions, yet definitive evidence that EMGBF is beneficial for increasing quadriceps strength could not be concluded because of the 4 studies demonstrating a wide CI.
Inter-limb Differences in Quadriceps Strength and Volitional Activation
In this crossover study, we wished to determine if normalized inter-limb differences in strength differed from inter-limb differences in voluntary activation at 30°, 70°, and 90° of knee flexion. We also assessed the relationship between inter-limb differences in torque with the inter-limb differences in activation. Twenty-five healthy volunteers were used for final data analyses; the order of leg tested, joint angle, and measurement technique (isokinetic strength, voluntary activation) were randomly assigned. Quadriceps strength was measured isokinetically at 1.05 rad · s(-1), while quadriceps voluntary activation was assessed via the central activation ratio. Absolute values of inter-limb differences for both measures were calculated by subtracting the non-dominant leg values from those of the dominant leg. Inter-limb isokinetic strength differences were greater than inter-limb central activation ratio differences at all joint angles (P = 0.003). Interestingly, inter-limb deficits between measures were not strongly correlated, suggesting that these measurements may be evaluating completely different phenomena within the neuromuscular system. These measurement techniques may provide unique information regarding neuromuscular function, suggesting that researchers and clinicians must utilize information from both techniques to determine the true clinical nature of inter-limb deficits.
Quadriceps Function in Anterior Cruciate Ligament-deficient Knees Exercising with Transcutaneous Electrical Nerve Stimulation and Cryotherapy: a Randomized Controlled Study
Objective: To compare strength and quadriceps muscle activation in anterior cruciate ligament-deficient patients who underwent a two-week rehabilitation exercise program using TENS or cryotherapy.Design: Randomized, controlled study.Setting: Clinical research laboratory.Subjects: Thirty patients: 20 males, 10 females, 31.6 (13.0) years, 172.8 (10.0) cm, 75.8 (13.0) kg with diagnosed tear of the anterior cruciate ligament.Interventions: All patients attended four sessions of supervised quadriceps strengthening exercises over two weeks, prior to reconstruction surgery. Patients were randomly allocated (n = 10/group) to receive exercises alone, exercise while wearing a sensory transcutaneous electrical nerve stimulation (TENS) device on the knee joint for the duration of each daily session, or 20 minutes of knee joint cryotherapy immediately prior to each daily exercise session.Main measures: Normalized knee extension force and quadriceps central activation ratio were measured before and after the first supervised treatment session and within 24 hours of the last session.Results: When accounting for differences in baseline measures, there were no statistically significant group differences immediately following the first exercise session for knee extension force (P = 0.10) or central activation ratio (P = 0.30) nor were there statistically significant group differences after the two-week intervention for knee extension force (P = 0.92) or central activation ratio (P = 0.94). Effect sizes for the change in knee extension force and central activation ratio after two weeks of therapy were all large.Conclusions: Quadriceps strength and central activation in anterior cruciate ligament deficient patients improved after two weeks of rehabilitaiton exercises, however, there were no significant differences between treatment groups.
A Microarray Biosensor for Multiplexed Detection of Microbes Using Grating-coupled Surface Plasmon Resonance Imaging
Grating-coupled surface plasmon resonance imaging (GCSPRI) utilizes an optical diffraction grating embossed on a gold-coated sensor chip to couple collimated incident light into surface plasmons. The angle at which this coupling occurs is sensitive to the capture of analyte at the chip surface. This approach permits the use of disposable biosensor chips that can be mass-produced at low cost and spotted in microarray format to greatly increase multiplexing capabilities. The current GCSPRI instrument has the capacity to simultaneously measure binding at over 1000 unique, discrete regions of interest (ROIs) by utilizing a compact microarray of antibodies or other specific capture molecules immobilized on the sensor chip. In this report, we describe the use of GCSPRI to directly detect multiple analytes over a large dynamic range, including soluble protein toxins, bacterial cells, and viruses, in near real-time. GCSPRI was used to detect a variety of agents that would be useful for diagnostic and environmental sensing purposes, including macromolecular antigens, a nontoxic form of Pseudomonas aeruginosa exotoxin A (ntPE), Bacillus globigii, Mycoplasma hyopneumoniae, Listeria monocytogenes, Escherichia coli, and M13 bacteriophage. These studies indicate that GCSPRI can be used to simultaneously assess the presence of toxins and pathogens, as well as quantify specific antibodies to environmental agents, in a rapid, label-free, and highly multiplexed assay requiring nanoliter amounts of capture reagents.
