Comparing the effects of mechanical perturbation training with a compliant surface and manual perturbation training on joints kinematics after ACL-rupture.

Only eight patients in the mechanical group completed analysis, and four of 12 enrolled dropped out, so the study is preliminary and may not reflect typical anterior cruciate ligament rehabilitation. The manual comparison group came from a previous randomized control study and was matched by age and sex, not randomly allocated at the same time as the mechanical group. Patients with quadriceps strength deficits also received progressive quadriceps strengthening, neuromuscular electrical stimulation or gym strengthening, so the study cannot separate the effect of perturbation training from the strengthening. Follow-up was within two weeks of training, so long-term effects on knee motion and joint integrity are unknown. Participants were regular Level I or II athletes with acute unilateral anterior cruciate ligament rupture, so findings may not apply to less active patients or patients with anterior cruciate ligament reconstruction. The variability of some walking angle measurements was as large as or larger than the average values, making the estimates imprecise.

The authors declared no affiliations or financial involvement with organizations having a direct financial interest. The article is listed as supported by NIH extramural research funds.

Do not conclude that mechanical compliant-surface training is a safer or better replacement for manual perturbation training. The study only showed different walking knee angles in eight analysable patients in each group, and the authors could not tell whether the reduced knee bend is a useful adaptation or a possible long-term joint health risk.