The effect of different hip rotation angles on electromyography activity of the quadriceps muscle during closed kinetic chain tasks in healthy females.
Neda Babadi, Mohammad Mohsen Roostayi, Abbas Rahimi and 3 others
PMID 30154611WHAT IT FOUND
Standing on toes with hip rotation did not selectively increase vastus medialis oblique activity compared to vastus lateralis in healthy females.
Vastus lateralis was consistently more active, meaning this position fails to target the medial stabilizer often needed for patellofemoral pain.
Key findings
01The hypothesis that vastus medialis oblique activity would be higher than vastus lateralis activity was not proven.
02During 15° and 30° of internal rotation, neutral position, and 15° of external rotation, vastus lateralis was more active than the other two muscles, significantly higher than rectus femoris but not significantly higher than vastus medialis oblique.
03Tip-toe standing exercises cannot be recommended for strengthening the vastus medialis oblique muscle because vastus lateralis activity was higher in all testing positions.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
Participants were healthy females without knee pain or pathology, so results may not apply to patients with patellofemoral syndrome who have existing muscle imbalances or pain inhibition. The study used a quasi-experimental design with no control group or randomization of participants to different conditions, though conditions were randomly sequenced for each person. EMG activity is a proxy for muscle recruitment and does not directly measure force production or joint stability.
Declared interests
The authors declared no competing financial interests, and the research did not receive specific grant funding.
The easy way to misread this
Do not interpret the lack of significant difference between VMO and VL as evidence that VMO is equally strong or effective in this position. The VL was consistently the dominant muscle, with the highest average activity across all exercises, meaning this task is likely to reinforce lateral pull rather than correct it.