Comparing power and activity of lower body muscles in two types of multiple sclerosis patients and healthy individuals

Multiple sclerosis (MS) is a chronic and debilitating disorder that renders degeneration of myelin within Central Nervous System (CNS). This study aimed to investigate the strength and muscle activity in two models of patients with multiple sclerosis in comparison to healthy individuals.

In this cross-sectional study, a population of women and men with diseases of MS province of Mazandaran were chosen. After informed consent 45 individuals were included in Relapsing-remitting multiple sclerosis (RR) model, 22 in Secondary progressive multiple sclerosis (SP) model, and 38 as a control group. In order to measure the maximum power of quadriceps muscles Brzycki's formula was used, while dynamometer was employed for assessing trunk muscles. Furthermore, the activities of tibialis anterior, medial gastrocnemius, peroneus longus and soleus muscles were assessed. The data were analysed using one-way analysis of variance, and for comparing intergroup differences Tuckey post-hoc test was utilized. 

There was a significant difference between healthy and MS groups (P<0.05). Moreover, the mean activity (P=0.001), maximum activity (P=0.001), co-contraction (P=0.004) and power of muscles (P=0.001) were higher in RR model than in SP model.

Disease progress pattern shows that both power and activity of muscles first increase and then decline. Thus, the RR period can be the best time for maintaining physical condition of MS patients and the initial phases of this debilitating disorder can be decisive in mitigating the future symptoms.