Correlation between hip function and knee kinematics evaluated by three-dimensional motion analysis during lateral and medial side-hopping.
Hiromitsu Itoh, Kohei Takiguchi, Yohei Shibata and 3 others
PMID 27799670WHAT IT FOUND
In 16 limbs of healthy male rugby players, side-hop landing differed by direction: lateral landing had more knee abduction, medial landing had more external rotation.
Hip internal rotation range was linked to greater knee external rotation and abduction loads during lateral landing only.
Key findings
01During lateral touchdown, the knee showed a significantly larger abduction angle than during medial touchdown, and during medial touchdown it showed a significantly larger external rotation angle.
02Hip internal rotation range of motion was significantly correlated with maximum knee external rotation angle and with maximum knee external rotation and abduction moments during lateral touchdown.
03No significant correlations were found between hip clinical parameters and knee kinematic or kinetic results during medial touchdown.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
Only 16 lower extremities in 11 athletes were analysed, and the authors state the small sample is not robust enough for definitive conclusions. The participants were healthy male rugby players, so the results may not apply to athletes of other sports, women, or people recovering from anterior cruciate ligament reconstruction. Some athletes contributed one limb and some contributed two, which the authors say may create uneven data distribution and bias. The study did not measure hip adduction or abduction range of motion, which the authors note could also relate to knee valgus motion. The design is cross-sectional, so it shows association at one time point, not that hip motion causes knee loading or that training would reduce risk.
The easy way to misread this
Do not conclude that hip internal rotation range causes risky knee loading or that hip exercises prevent anterior cruciate ligament injury. The study measured 16 limbs of healthy male rugby players and found links during side hopping, not a tested intervention or injury outcomes.