Lower-Limb Biomechanical Characteristics Associated with Unplanned Gait Termination Under Different Walking Speeds

This study compared the biomechanical characteristics of the lower extremity during unplanned gait termination under different walking speeds. The lower-limb kinematic and kinetic data from fifteen subjects with normal and fast walking speeds were collected using a motion analysis system and plantar pressure platform.

This measure can be used to investigate key question in lower-limb biomechanical characteristics that are occurring during unplanned gait termination under different walking speeds. The main advantage of this technique is that it can prove some specific details for exploring potential injury risks associated with gait termination. Before the test interview all subjects and provide them with a simple explanation about the experimental goals and procedures.

Obtain written informed consent from subjects who meet the key inclusion criteria. Include subjects who are physically active male adults, have the right leg as dominant, do not have any hearing disorder, do not have lower-limb disorders, and have not incurred injuries in the last 6 months. Instruct all subjects to fill out a survey with questions such as have you had a history of running or other physical activities?

How often do you do physical activities in a week? Do you have any professional athletic training? And have you suffered any lower-limb disorders and injuries in the last 6 months?

Ensure that all subjects wear identical t-shirts and tight-fitting pants. Measure subject standing height and body weight, lower-limb length, knee width, and ankle with of both left and right leg using a Vernier caliper or a small anthropometer. Shave off body hair where appropriate and remove excess sweat using alcohol wipes to prepare skin areas of anatomical bony landmarks for marker placement on joints and segments.

Identify 16 anatomical landmarks and attach passive retroreflective markers with double-sided adhesive tapes. Give each subject 5 minutes to adapt to the test environment and warm up with light running and stretching. Once the subject is at the starting position, open the kinematics motion capture system, select the Go Live button in the resources pane, and click Capture in the right tool bar.

Find trial type and session and edit the trial description. Ask subjects to walk along a walkway at their normal walking speed and instruct them to use the dominant and non-dominant leg to pass areas A and B respectively, and then to stop at area D on the pressure platform. Let the subject know that when the termination signal is provided, they need to quickly stop at B.Randomly provide the termination signal as the heel touches area A ensuring that the unexpected gait termination or UGT is executed.

After finishing the UGT test click stop to end the data collection trial. Capture at least 5 success of UGT trials with 2 minute rest intervals between trials. Calculate each subject's walking speed using the pressure platform software, then calculate the fast walking speed as 125%of the normal walking speed.

To calculate plantar pressure select the measure button before starting the UGT trials. After finishing the UGT test, click save measurement button to save the data. Repeat the test at fast walking speed to capture at least 5 successive trials.

This protocol was used to compare the biomechanical characteristics of the lower extremity during unplanned gait termination under different walking speeds. Data was collected from 15 subjects. Mean normal and fast walking speeds of the subjects were 1.33 and 1.62 meters per second respectively.

The mean range of motion of the hip, knee, and ankle joints in the sagittal plane during unplanned gait termination at normal and fast walking speeds is shown here. Compared with normal walking speed, the range of motion of 3 joints increased significantly at fast walking speed. The plantar pressure data, including maximum pressure, maximum force, and contact area during unplanned gait termination is shown here.

Compared with normal walking speed, the maximum pressure in BT, M1, M2, M3, MH, and LH regions increased significantly at fast walking speed. Similarly, the maximum force increased significantly in BT, M1, M2, M3, MH, and LH at fast walking speed. Differences in contact area occurred in the heel region, MH and LH, both increasing at fast walking speed.

No significant difference occurred in any parameters for the OT, M4, M5, and MF regions. During this procedure the effect of different speeds was different static patterns on muscle activities and the joint moments during gait termination can be researched. Gait termination tries could be used as effective tool for diagnoses of clinical biomechanical performance and assessment of a rehabilitation treatment.