Effects of long-term resistance training and simultaneous electro-stimulation on muscle strength and functional mobility in multiple sclerosis

Abstract

Background: Resistance training studies in multiple sclerosis (MS) often use short intervention periods. Furthermore, training efficiency could be optimized by unilateral training and/or electrical stimulation.

Objective: To examine the effect(s) of unilateral long-term (20 weeks) standardized resistance training with and without simultaneous electro-stimulation on leg muscle strength and overall functional mobility.

Methods: A randomized controlled trial involving 36 persons with MS. At baseline (PRE) and after 10 (MID) and 20 (POST) weeks of standardized (ACSM) light to moderately intense unilateral leg resistance training (RES(O), n = 11) only or resistance training with simultaneous electro-stimulation (RES(E), n = 11, 100 Hz, biphasic symmetrical wave, 400 µs), maximal isometric strength of the knee extensors and flexors (45°, 90° knee angle) and dynamic (60-180°/s) knee-extensor strength was measured and compared with a control group (CON, n = 14). Functional mobility was evaluated using the Timed Get Up and Go, Timed 25 Foot Walk, Two-Minute Walk Test, Functional Reach and Rivermead Mobility Index.

Results: Maximal isometric knee extensor (90°, MID: +10 ± 3%, POST: +10 ± 4%) in RES(O) and knee flexor (45°, POST: +7 ± 4%; 90°, POST: +9 ± 5%) in RES(E) strength increased (p < 0.05) compared with CON but RES(O) and RES(E) did not differ. Also, impaired legs responded positively to resistance training (unilateral leg strength analysis) and functional reaching increased significantly in RES(O) (+18%) compared with CON. Dynamic muscle strength and the remaining functional mobility tests did not change.

Conclusion: Long-term light to moderately intense resistance training improves muscle strength in persons with MS but simultaneous electro-stimulation does not further improve training outcome.