Immediate effects of cryotherapy on neuromuscular performance of ankle joint and on gait pattern of chronic spastic hemiparetic subjects post stroke

Abstract

Stroke has been described as the third cause of death and the leading cause of disability in adults worldwide. Although about 60% of surviving individuals are able to walk after rehabilitation, deficits in the functions of the lower limbs often persist in the majority of cases, affecting gait and functional mobility. In this context, several interventions are applied in clinical practice to optimize functional performance. Cryotherapy is among the most used techniques in order to reduce spasticity temporarily, allowing the realization of functional training, such as walking. The aim of this project is to evaluate the effects of cryotherapy (ice pack) on neuromuscular performance and the passive resistance of the dorsiflexors and plantar flexors ankle muscles, as well as on gait performance in chronic hemiparetic and in healthy subjects. Eighteen chronic hemiparetic subjects, and eighteen healthy subjects, matched for gender and age with the hemiparetic group, will participate in the study. Cryotherapy will be applied on the back of the leg, in the form of crushed ice pack for 20 minutes. Initially, Berg Balance Scale and Fugl Meyer Scale will be applied. All other variables will be assessed before and after application of cryotherapy: the level of spasticity will be evaluated according to the classification of the Modified Ashworth Scale; spatiotemporal parameters and three-dimensional joint kinematics of the trunk, hip, knee and ankle during gait will be analyzed using a system of movement analysis (AB Qualysis, Gotheburg, Sweden); resistance to passive stretching, and peak torque, average torque, work and power in isometric and isokinetic (concentric and eccentric) contractions of the plantar flexors and dorsiflexors ankle muscles will be obtained using an isokinetic dynamometer; peak activation of soleus, gastrocnemius (medialis and lateralis), tibialis anterior and peroneus (longus and brevis), coactivation index between agonists and antagonists, time for onset of muscle activation ("onset") and order of muscle recruitment will be obtained by electromyography. For statistical analysis, tests for normality (Shapiro Wilk) and homogeneity (Levene's test) will be applied. If variables were normal and homogenous, the ANOVA two-way test will be applied. Otherwise, the non-parametric Kruskal-Wallis statistics will be applied. A significance level of 0.05 will be considered for all statistical tests. (AU)