Maximal Strength Training in MS: Effects on Mobility Deficits

Background: : Physical therapists may resist prescribing high intensity strength training for patients with MS (pwMS) due to concerns about fatigue. Our recently  published  a pilot study showed that Maximum Strength Training (MST), is safe and feasible in pwMS, with subjects showing improvements in strength, Six Minute Walk Test (6MWT) , and Berg Balance Scale scores following a 6 week training program.

Objectives: The purpose of this current study is  to repeat the MST protocol with a larger sample, a larger intervention, and more extensive evaluation. We hypothesize that the pilot study findings will be confirmed and strengthened, with pwMS showing improvements in all measures of function and strength without adverse effects. If our hypothesis is correct, it will reaffirm that MST is a safe, feasible, and effective intervention to improve gait and balance in pwMS, as well as provide more specific guidelines to utilize this intervention.

Methods: Subjects with a definitive diagnosis of MS were recruited from  MS specialty practices. .A pretest/posttest design was used. Baseline demographic measures and subject characteristics including EDSS, Multiple Sclerosis Impact Scale-29, Fatigue Severity Scale (FSS), and Modified Ashworth Scale (MAS) were collected. Strength of hip extensors, knee flexors, and ankle plantarflexors was collected via handheld dynamometry. Mobility outcome measures included the 6MWT, the Mini-BESTest (MBT) and the Stair Climbing Power Test (SCPT). Subjects completed a 2x/week program for 8 weeks of leg press, knee flexion, and ankle plantarflexion, performing 4 sets of 4 repetitions of each leg at 85-95% of their 1RM, completing 2 out of 3 exercises per session. Increases in weight for subsequent session were determined by subject capability and preference. Fatigue was measured each session using the Visual Analog Scale of Fatigue, and weekly with the Fatigue Severity Scale (FSS). 

Results: To date, 9 subjects (6 females, 3 males), EDSS 4.25 have completed the program. Paired sample T-tests revealed statistically significant differences in the 6MWT from in pre (M=1110, SD=743) to post MST (M=1208, SD=785) MST intervention; (p = .008). In the MBT, a significant difference was found between pre (M=13.6, SD=8.4) and post MST (M=15.3, SD=8.8) scores; (p=.035). FSS and MAS scores did not change significantly from pretest to posttest suggesting that the intervention did not increase fatigue or spasticity.  

Conclusions: The relatively wide range of EDSS scores suggest that the MST program can be utilized in wide spectrum of disability. The improvements in gait and balance occurred despite the absence of specific gait and balance interventions. The results of this ongoing study are consistent with and expands upon our previous work, suggesting MST is a safe and effective intervention, and that pwMS can benefit from a higher intensity of intervention than might have previously been thought.