The effect of trunk and shank position on the hip-to-knee moment ratio in a bilateral squat.
Kerri A Graber, Anne L Halverstadt, Simone V Gill and 2 others
PMID 37001335WHAT IT FOUND
In 100 adults doing body-weight squats, more forward trunk lean was linked to greater hip extensor moment relative to knee extensor moment.
More forward shank lean showed the opposite. Trunk lean had the stronger link.
Key findings
01A one-degree increase in trunk angle increased the hip-to-knee moment ratio by 2%, and a one-degree increase in shank angle decreased it by 2.9%.
02Trunk angle was the largest predictor of the hip-to-knee moment ratio, explaining 35% of the variance.
03The hip-to-knee moment ratio increased with greater squat depth and decreased with greater shank angle.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
Participants chose their own trunk and shank positions, so the study shows associations, not that changing position or cueing changes moments. Squats were body-weight only on level ground, so results may not apply to weighted squats, heels-elevated squats, or single-leg squats. The sample was mainly young adults, with average age 25.5 years, so findings may not generalize to older adults. Only depths from 60 to 110 degrees of knee flexion were analyzed because fewer than 50% of participants reached 120 degrees, so very deep squats are not covered. Hip pain status was present in some participants but not analyzed as a factor affecting angles or moments, though results were similar when group was included.
The easy way to misread this
Do not conclude that cueing a patient to lean the trunk forward will change hip or knee moments. The study measured self-selected body-weight squat patterns and only found associations.