Resistance training improves strength and functional capacity in persons with multiple sclerosis
White LJ, McCoy SC, Castellano V, Gutierrez G, Stevens JE, et al.;
Commented by , 22 Mar 2005
Background
Rehabilitation is a cornerstone in the treatment of MS related disability. Advances in drug therapy have led to modification of disease course, and the need for sustenance or improvement of motor function and activities of daily living is obvious. Aerobic exercise has been shown to improve muscle strength, cardiovascular fitness and ambulate function and furthermore reduce fatigue. Resistance training is widely used in rehabilitation but the effect is not well described.
Aim
To evaluate the effectiveness of resistance training on muscle strength, ambulation, fatigue and perceived disability in patients with MS.
Methods
The authors studied 8 individuals with self-reported disability (EDSS) 3,7. The subjects completed supervised resistance training for eight weeks, twice weekly. During the first week subjects performed 6-10 repetitions at 50% of maximal voluntary contraction (MVC), the second week 10-15 repetitions of 60% MVC.
In subsequent sessions 10-15 repetitions at 70% of maximum predicted force for all lower body exercises. An isokinetic dynamometer was used for muscle strength testing and a central activation was calculated by dividing maximum voluntary force by maximum superimposed electrical stimulation. Quantification of the muscle contractile area in the thigh was determined by using MRI.
Ambulatory function was measured using 25-ft. walking test as well as a 3-minute step test. Self reported measurements of fatigue (MFIS) and disability (EDSS) were also assessed before and after the eight-week training program.
Results
Significant increase of muscle strength was found for knee extension (7.4%, p=0.03) and plantar flexion (52%).
Stepping performance increased significantly (8.7%, p<0,05), but walking speed was unchanged.
Self-reported fatigue decreased (p<0,05) and there was a trend of decreasing self reported disability (p=0.07) during the study.
Muscle cross-sectional area and volume remained unchanged from pretraining volumes. Central activation ratio also remained unchanged.
Dr Blinkenberg's comments
The study shows that resistance training improve strength for muscle groups in the lower extremities, which notoriously are less affected by the characteristic supranuclear palsy seen in MS. The training program increased stepping performance, but walking speed was unchanged. In this way the functional gain of the program was limited.
The authors report a trend of decreasing disability although this was a self reported measurement and the significance therefore dubious. Furthermore, the study design was without control group and not randomized. Taking these considerations into account the conclusions of the study are weak and should be considered as guiding and hypothesis generating.
The reported effect on fatigue is interesting and corroborates studies of aerobic exercise. Muscle weakness and fatigue are two of the most disabling symptoms in MS disease and it is important to stress the importance of training and exercise in the counseling of MS patients, even in the early stage of disease.
The significance of composing the optimal training program in the rehabilitation setting is evident and in this regard the study has weak conclusions showing modest effect of resistance training.