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Modulation in voluntary neural drive in relation to muscle soreness.

Racinais S, Bringard A, Puchaux K, Noakes TD, Perrey S - Eur. J. Appl. Physiol. (2007)

Bottom Line: Immediately after exercise there was a -15% decrease in MVT of the plantar flexors partly attributable to an alteration in contractile properties (-23% in electrically evoked mechanical twitch).However, MVT failed to recover before the third day whereas the contractile properties had significantly recovered within the first day.The decrease in voluntary activation occurred in the absence of any variation in spinal modulation estimated from the H-reflex.

View Article: PubMed Central - PubMed

Affiliation: Motor Efficiency and Deficiency Laboratory, EA 2991, UFR STAPS, Montpellier, France. contact@sebastienracinais.com

ABSTRACT
The aim of this study was to investigate whether (1) spinal modulation would change after non-exhausting eccentric exercise of the plantar flexor muscles that produced muscle soreness and (2) central modulation of the motor command would be linked to the development of muscle soreness. Ten healthy subjects volunteered to perform a single bout of backward downhill walking exercise (duration 30 min, velocity 1 ms(-1), negative grade -25%, load 12% of body weight). Neuromuscular test sessions [H-reflex, M-wave, maximal voluntary torque (MVT)] were performed before, immediately after, as well as 1-3 days after the exercise bout. Immediately after exercise there was a -15% decrease in MVT of the plantar flexors partly attributable to an alteration in contractile properties (-23% in electrically evoked mechanical twitch). However, MVT failed to recover before the third day whereas the contractile properties had significantly recovered within the first day. This delayed recovery of MVT was likely related to a decrement in voluntary muscle drive. The decrease in voluntary activation occurred in the absence of any variation in spinal modulation estimated from the H-reflex. Our findings suggest the development of a supraspinal modulation perhaps linked to the presence of muscle soreness.

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Related in: MedlinePlus

Experimental design. Thin arrow indicates stimulation at Hmax intensity, simple thick arrow indicates stimulation at Mmax intensity, double thick arrow indicates doublet at Mmax intensity
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Fig1: Experimental design. Thin arrow indicates stimulation at Hmax intensity, simple thick arrow indicates stimulation at Mmax intensity, double thick arrow indicates doublet at Mmax intensity

Mentions: Subjects visited our laboratory on four consecutive days (Fig. 1). The first day consisted of a neuromuscular test session (described subsequently) followed by a backward walking exercise (description below) followed by further neuromuscular testing. On the second, third and fourth days, subjects returned to the laboratory at the same hour of day that they had finished the walking exercise and performed the neuromuscular testing.Fig. 1


Modulation in voluntary neural drive in relation to muscle soreness.

Racinais S, Bringard A, Puchaux K, Noakes TD, Perrey S - Eur. J. Appl. Physiol. (2007)

Experimental design. Thin arrow indicates stimulation at Hmax intensity, simple thick arrow indicates stimulation at Mmax intensity, double thick arrow indicates doublet at Mmax intensity
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2267484&req=5

Fig1: Experimental design. Thin arrow indicates stimulation at Hmax intensity, simple thick arrow indicates stimulation at Mmax intensity, double thick arrow indicates doublet at Mmax intensity
Mentions: Subjects visited our laboratory on four consecutive days (Fig. 1). The first day consisted of a neuromuscular test session (described subsequently) followed by a backward walking exercise (description below) followed by further neuromuscular testing. On the second, third and fourth days, subjects returned to the laboratory at the same hour of day that they had finished the walking exercise and performed the neuromuscular testing.Fig. 1

Bottom Line: Immediately after exercise there was a -15% decrease in MVT of the plantar flexors partly attributable to an alteration in contractile properties (-23% in electrically evoked mechanical twitch).However, MVT failed to recover before the third day whereas the contractile properties had significantly recovered within the first day.The decrease in voluntary activation occurred in the absence of any variation in spinal modulation estimated from the H-reflex.

View Article: PubMed Central - PubMed

Affiliation: Motor Efficiency and Deficiency Laboratory, EA 2991, UFR STAPS, Montpellier, France. contact@sebastienracinais.com

ABSTRACT
The aim of this study was to investigate whether (1) spinal modulation would change after non-exhausting eccentric exercise of the plantar flexor muscles that produced muscle soreness and (2) central modulation of the motor command would be linked to the development of muscle soreness. Ten healthy subjects volunteered to perform a single bout of backward downhill walking exercise (duration 30 min, velocity 1 ms(-1), negative grade -25%, load 12% of body weight). Neuromuscular test sessions [H-reflex, M-wave, maximal voluntary torque (MVT)] were performed before, immediately after, as well as 1-3 days after the exercise bout. Immediately after exercise there was a -15% decrease in MVT of the plantar flexors partly attributable to an alteration in contractile properties (-23% in electrically evoked mechanical twitch). However, MVT failed to recover before the third day whereas the contractile properties had significantly recovered within the first day. This delayed recovery of MVT was likely related to a decrement in voluntary muscle drive. The decrease in voluntary activation occurred in the absence of any variation in spinal modulation estimated from the H-reflex. Our findings suggest the development of a supraspinal modulation perhaps linked to the presence of muscle soreness.

Show MeSH
Related in: MedlinePlus