Muscular activation changes in lower limbs after underwater gait training in Parkinson's disease: A surface EMG pilot study

Abstract Background Under water gait training (UT) has been proposed as an innovative rehabilitative strategy for the treatment of axial disorders in Parkinson Disease (PD) patients, in particular for balance and gait impairment. However, the basis for the improvement is unclear. Research question The aim of this study was to evaluate improvements in the muscular activation in the lower limbs in a cohort of PD patients after UT. Methods Ten PD subjects and 10 controls (mean ± standard deviation of age and BMI were respectively: 71 ± 6 years and 28 ± 3 kg/m2; 65.5 ± 7 years and 28 ± 3 kg/m2) were enrolled in the study. After signing informed consent, the subjects walked barefoot at their preferred speed on a 10 m walkway, before and after UT (the PD subjects walked in the “off” state). The electrical activity of the following four muscles was collected bilaterally through a surface electromyographic system (sEMG): Rectus Femoris, Tibialis Anterior, Biceps Femoris and Gastrocnemius Lateralis. Ground reaction forces and motion capture data were synchronously acquired with the sEMG. The linear envelope of the sEMG signal, normalized with respect to its mean dynamic value, the peak of the Envelope and its occurrence with respect to the gait cycle (PoPE%) were computed, together with the spatiotemporal parameters. Results Our results showed that UT in PD patients improved the muscle’s recruitment pattern towards normal. The PD patients PoPE% was comparable with the one of the controls (e.g: TA: 20-35% and 75-80% of gait cycle; GL: 0-15%, 25-45% and 85-100% of gait cycle) after UT on each muscle with the exception of BF. The muscle co-activation plots failed to show improvement in line with the muscle activation. Significance These results suggest that the muscle activation improvement with UT in PD subjects maybe due to a reorganisation at the executive rather than at the command level.