Lumbar lordosis angle and trunk and lower-limb electromyographic activity comparison in hip neutral position and external rotation during back squats.
Tomoki Oshikawa, Yasuhiro Morimoto, Koji Kaneoka
PMID 29581666WHAT IT FOUND
For experienced lifters, turning feet out 45 degrees during full squats increased glute activity and lowered lower-back muscle strain compared to straight toes.
During parallel squats, turning feet out increased the arch in the lower back during the lift.
Key findings
01During full squats, external hip rotation significantly increased gluteus maximus activity and decreased lumbar erector spinae and multifidus activity compared to neutral hip rotation.
02During parallel squats, external hip rotation significantly increased the lumbar lordosis angle during the former concentric phase compared to neutral hip rotation.
03The study did not find significant differences in muscle activity or lumbar angle between hip positions for most phases of the parallel squat.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
The sample was very small (10 healthy males) and specifically experienced with back squats, so results cannot be generalized to beginners, females, or patients with existing pain. The researchers could not measure pelvic tilt because the markers were hidden by the body during deep squats, meaning the mechanical cause of the changes remains unconfirmed. The study measured muscle activity and spinal angle, not pain, injury rates, or clinical outcomes. The study did not define a primary outcome, so the reported differences are the result of multiple comparisons across many muscles and phases.
Declared interests
None declared.
The easy way to misread this
Do not assume that turning the feet out during squats prevents low back pain or improves safety for all patients. This study measured muscle activity in ten healthy, trained men, not pain or injury outcomes, and it found that external rotation actually increased the lumbar arch during parallel squats.