Protection against muscle damage induced by electrical stimulation: efficiency of a preconditioning programme.
OBJECTIVE
The aim of this study was to explore the efficiency of a preconditioning programme composed of neuromuscular electrical stimulation (NMES) in the protection against muscle damage induced by a subsequent bout of NMES.


METHODS
Sixteen male volunteers were split up into a control group (CG; n = 8) and a preconditioned group (PCG; n = 8). Both groups attended two NMES bouts (test 1 and test 2) spaced 5 weeks apart. Each one consisted in 100 quadriceps contractions and 100 hamstrings contractions. PCG attended five additional progressive NMES sessions between test 1 and test 2. The outcome measures were the changes in muscle soreness [0-10 pain score on visual analogue pain scale (VAS)], muscle flexibility and serum creatine kinase (CK) activity; they were assessed before (pre-T1) and after (post-T1) test 1 and before (pre-T2) and after (post-T2) test 2.


RESULTS
Damage markers increased similarly in both groups after test 1 (at post-T1, VAS scores = 4·18 ± 2 and 4·43 ± 1·56 cm in CG and PCG, respectively; CK activity = 2307 ± 3774 and 1671 ± 1790 IU l(-1) in CG and PCG, respectively). Compared with test 1, these damage markers were reduced after test 2 in CG (at post-T2, VAS score = 2·68 ± 1·27 cm and CK activity = 218 ± 72 IU l(-1) ). Muscle soreness was further reduced after test 2 in PCG (VAS score = 0·37 ± 0·74 cm).


CONCLUSIONS
A protective effect against muscle damage can be obtained after only one NMES bout, and an additional protective effect can be induced by a preconditioning programme.
Department of Sport and Rehabilitation, University of Liège, Liège, Belgium.
Marc
M
Vanderthommen
Department of Sport and Rehabilitation, University of Liège, Liège, Belgium.
Remy
R
Chamayou
Department of Sport and Rehabilitation, University of Liège, Liège, Belgium.
Christophe
C
Demoulin
Department of Sport and Rehabilitation, University of Liège, Liège, Belgium.
Jean-Michel
JM
Crielaard
Department of Sport and Rehabilitation, University of Liège, Liège, Belgium.
Jean-Louis
JL
Croisier
D000328:Adult; D004599:Electric Stimulation Therapy / Q000009:adverse effects*; D005081:Exercise Therapy / Q000379:methods; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000293:injuries* / Q000503:physiopathology*; D063806:Myalgia / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control; D064797:Physical Conditioning, Human / Q000379:methods*; D017695:Soft Tissue Injuries / Q000209:etiology / Q000503:physiopathology* / Q000517:prevention & control*; D016896:Treatment Outcome
delayed onset of muscle soreness; muscle adaptation; muscle damage; neuromuscular electrical stimulation; repeated bout effect