In this study of 12 classical female ballet dancers, jump height was tested in both turn out and in a neutral hip position. This study was essentially looking at the effects of external hip rotation turn out on lower limb kinematics. The study seemed to control for forward trunk lean, but it is unclear if this included anterior or pelvis tilt pre-posturing. After all, we know very well that anterior pelvis tilt (APT) will significantly inhibit gluteal function (go ahead, dump into APT and try to fire your glutes ! Nadda !)
Here are the study results:
"The dancers jumped lower in the TJ (turn out) than in the NJ (neutral). The knee extensor and hip abductor torques were smaller, whereas the hip external rotator torque was larger in the TJ than in the NJ. The work done by the hip joint moments in the sagittal plane was 0.28 J/(Body mass*Height) and 0.33 J/(Body mass*Height) in the TJ and NJ, respectively. The joint work done by the lower limbs were not different between the two jumps. These differences resulted from different planes in which the lower limb flexion-extension occurred, i.e. in the sagittal or frontal plane. This would prevent the forward lean of the trunk by decreasing the hip joint work in the sagittal plane and reduce the knee extensor torque in the jump."
So, when was the last time your sport allowed you to jump cleanly from the neutral hip and pelvis position? Not likely right ?! So, our rehab and our training must include non-neutral drills and skills, since that is where we live most of the time in our sporting and active lives.
Sports Biomech. 2017 Mar;16(1):87-101. doi: 10.1080/14763141.2016.1205122. Epub 2016 Jul 14.
Comparison of lower limb kinetics during vertical jumps in turnout and neutral foot positions by classical ballet dancers.
Imura A1, Iino Y1.