Stair Biomechanics and Vibration Study After ACLR

Visit 1 control condition; Visit 2 whole-body vibration; Visit 3 local muscle vibration (at least 48 hours apart)

Standing on a vibrating platform (Power Plate Pro 5) in a squatted position (approximately 60 degrees of knee flexion), 30 Hz, 2 g, 1 minute x 6 exposures with 2 minutes of rest.

• VCI

A vibration device secured over the quadriceps muscle belly while standing in the same squatted position on the deactivated platform, 30 Hz, 2 g, 1 minute x 6 exposures with 2 minutes of rest.

• LMV

Same squatted position and timing (1 minute x 6 exposures with 2 minutes of rest) without vibration.

Visit 1 control condition; Visit 2 local muscle vibration; Visit 3 whole-body vibration (at least 48 hours apart)

Standing on a vibrating platform (Power Plate Pro 5) in a squatted position (approximately 60 degrees of knee flexion), 30 Hz, 2 g, 1 minute x 6 exposures with 2 minutes of rest.

• VCI

A vibration device secured over the quadriceps muscle belly while standing in the same squatted position on the deactivated platform, 30 Hz, 2 g, 1 minute x 6 exposures with 2 minutes of rest.

• LMV

Same squatted position and timing (1 minute x 6 exposures with 2 minutes of rest) without vibration.

Single visit with the control condition; matched to ACLR participants by sex, age, (within 3 years), and Tegner activity level (within 1 level).

Same squatted position and timing (1 minute x 6 exposures with 2 minutes of rest) without vibration.

Maximum hip flexion angle during stance (degrees). Measured with 3D motion capture and force plates during the stance phase of preferred-speed overground gait, stair ascent, and stair descent (5 trials per task, averaged), in both limbs of participants with ACLR and healthy controls.

Maximum hip flexion angle during stance (degrees). Measured with 3D motion capture and force plates during the stance phase of preferred-speed overground gait, stair ascent, and stair descent (5 trials per task, averaged), in both limbs of participants with ACLR and healthy controls.

Maximum ankle dorsiflexion angle during stance (degrees). Measured with 3D motion capture and force plates during the stance phase of preferred-speed overground gait, stair ascent, and stair descent (5 trials per task, averaged), in both limbs of participants with ACLR and healthy controls.

Peak knee valgus (abduction) angle during stance (degrees). Measured with 3D motion capture and force plates during the stance phase of preferred-speed overground gait, stair ascent, and stair descent (5 trials per task, averaged), in both limbs of participants with ACLR and healthy controls.

Change in knee flexion angle from initial contact to peak knee flexion during stance (degrees). Measured with 3D motion capture and force plates during the stance phase of preferred-speed overground gait, stair ascent, and stair descent (5 trials per task, averaged), in both limbs of participants with ACLR and healthy controls.

Peak internal knee extension moment during stance, normalized to body weight x height. Measured with 3D motion capture and force plates during the stance phase of preferred-speed overground gait, stair ascent, and stair descent (5 trials per task, averaged), in both limbs of participants with ACLR and healthy controls.

Peak internal knee abduction moment (equivalent to the external knee adduction moment) during stance, normalized to body weight x height. Measured with 3D motion capture and force plates during the stance phase of preferred-speed overground gait, stair ascent, and stair descent (5 trials per task, averaged), in both limbs of participants with ACLR and healthy controls.

Peak vertical ground reaction force during stance, normalized to body weight (xBW). Measured with 3D motion capture and force plates during the stance phase of preferred-speed overground gait, stair ascent, and stair descent (5 trials per task, averaged), in both limbs of participants with ACLR and healthy controls.

Peak anterior tibial shear force during stance, normalized to body weight (xBW). Measured with 3D motion capture and force plates during the stance phase of preferred-speed overground gait, stair ascent, and stair descent (5 trials per task, averaged), in both limbs of participants with ACLR and healthy controls.

Maximal voluntary isometric knee extension torque measured on an isokinetic dynamometer (knee flexed 90 degrees, hip flexed 85 degrees); mean of 3 contractions per limb, normalized to body mass (Nm/kg).

Maximal voluntary isometric knee flexion torque measured on an isokinetic dynamometer (knee flexed 90 degrees, hip flexed 85 degrees); mean of 3 contractions per limb, normalized to body mass (Nm/kg).

Rate of torque development during maximal voluntary isometric knee extension contractions; mean of 3 contractions per limb, normalized to body mass (Nm/kg/s).

Rate of torque development during maximal voluntary isometric knee flexion contractions; mean of 3 contractions per limb, normalized to body mass (Nm/kg/s).

Distance hopped on one leg, measured from the take-off line to the landing point of the heel; mean of 3 successful trials per limb (cm).

Distance covered in three consecutive hops on one leg, measured from the take-off line to the landing point of the heel; mean of 3 successful trials per limb (cm).

Self-reported knee symptoms, function, and sports activity; score 0 to 100, higher scores indicate better knee function. Baseline patient-reported measure collected for participant characterization and prespecified covariate analyses.

Five subscales (Pain, Symptoms, Activities of Daily Living, Sport and Recreation, Knee-Related Quality of Life), each scored 0 to 100, higher scores indicate fewer problems. Baseline patient-reported measure collected for participant characterization and prespecified covariate analyses.

Fear of movement and re-injury; score 11 to 44, higher scores indicate greater fear. Baseline patient-reported measure collected for participant characterization and prespecified covariate analyses.

Activity level; score 0 to 10, higher scores indicate higher activity levels. Baseline patient-reported measure collected for participant characterization and prespecified covariate analyses.

Frequency of running, cutting, decelerating, and pivoting; score 0 to 16, higher scores indicate more frequent activity. Baseline patient-reported measure collected for participant characterization and prespecified covariate analyses.

ACL-specific quality of life; score 0 to 100, higher scores indicate better quality of life. Baseline patient-reported measure collected for participant characterization and prespecified covariate analyses.

Self-reported return-to-activity status and reasons for limited physical activity after ACL injury. The survey has no total score. Responses will be reported descriptively as the number (%) of participants cleared to return to unrestricted activity, the number (%) in each activity category (as physically active as before injury; as active but participation is more challenging; less active than before injury), the number (%) selecting each of the 14 listed reasons, and the number (%) ranking each reason as most important. Reported for participants with ACLR. Baseline patient-reported measure collected for participant characterization and prespecified covariate analyses.