Knee dynamics during take-off and landing in spike jumps performed by volleyball players with patellar tendinopathy.
Kazuhiro Obara, Ryosuke Chiba, Mirai Takahashi and 2 others
PMID 35221512WHAT IT FOUND
Volleyball players with medial patellar tendinopathy showed no difference in knee angles during jumps.
However, their injured knee displayed opposite rotational forces and ground reaction vectors passing laterally, unlike the healthy controls.
Key findings
01There were no significant differences in knee joint angles between players with patellar tendinopathy and healthy controls during spike jumps.
02Players with patellar tendinopathy exhibited significant differences in knee joint moments, specifically adduction and internal rotation on the injured side, compared to controls.
03Ground reaction force vectors passed through the lateral side of the knee in all trials for the injured leg of patients, whereas they passed medially for healthy controls.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
The sample size was very small, with only 6 patients and 7 controls, limiting the generalizability of the findings. The study was cross-sectional, so it cannot determine if the observed biomechanical differences caused the tendinopathy or resulted from adapting to pain. Participants were matched for intrinsic and extrinsic factors, but individual anatomical variations not measured could influence results.
Declared interests
The work was supported by a JSPS KAKENHI grant, and the authors declared no conflicts of interest.
The easy way to misread this
Do not assume that correcting knee angles will resolve patellar tendinopathy, as no significant differences in angles were found between players with and without the condition.