Vitamin and mineral supplementation and neuromuscular recovery after a running race.
OBJECTIVE
This double-blind study investigated the effects of vitamin and mineral complex supplementation on the neuromuscular function of the knee-extensor muscles after a prolonged trail running race.


METHODS
Twenty-two well-trained endurance runners took either placebo (Pl group) or vitamins and minerals (Vm group) for 21 d before the race and for 2 d after the race. Maximal voluntary contractions (MVC) and surface EMG activity of the vastus lateralis (VL) muscle were recorded before (pre) and 1 h (post), 24 h (post 24) and 48 h (post 48) after the race. Central activation ratio (CAR), neural (M-wave), and contractile (muscular twitch) properties of the quadriceps muscles were analyzed using electrical stimulation techniques.


RESULTS
The knee-extensor MVC was significantly (P < 0.01) reduced after exercise for both groups (Vm: 36.5 +/- 3.0 %; Pl: 36.9 +/- 2.1%), but MVC recovery was greater for Vm than Pl after 48 h (11%, P < 0.05). The reduced MVC after exercise was associated with a significant reduction in maximal EMG normalized to the M-wave in VL muscle and in CAR for both groups. Characteristics of the muscular twitch were not significantly altered for either groups, whereas M-wave duration increased significantly (P < 0.05) after exercise.


CONCLUSIONS
The reduction of MVC immediately after the race appeared to result from peripheral mechanisms such as a failure in muscle membrane excitation and, to a lesser extent, from reduced central activation. The cause of the depressed MVC 24 h after the race seemed to be located within the muscle itself. A dietary supplementation of a vitamin and mineral complex does not attenuate the loss of contractile function immediately after the running exercise, and it may accelerate the recovery of maximal force capacity.
Gauche
Elodie
E
Laboratory of Biomechanics and Physiology, National Institute of the Sport and Physical Education, Paris, France.
Lepers
Romuald
R
Rabita
Giuseppe
G
Leveque
Jean-Michel
JM
Bishop
David
D
Brisswalter
Jeanick
J
Hausswirth
Christophe
C
D000328:Adult; D019587:Dietary Supplements; D004311:Double-Blind Method; D004576:Electromyography; D006801:Humans; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology; D053580:Muscle Strength / Q000187:drug effects / Q000502:physiology; D020127:Recovery of Function / Q000187:drug effects* / Q000502:physiology; D012420:Running / Q000502:physiology*; D014131:Trace Elements / Q000494:pharmacology*; D014815:Vitamins / Q000494:pharmacology*
D014131:Trace Elements; D014815:Vitamins