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Spinal modulations accompany peripheral fatigue during prolonged tennis playing
Author(s) -
Girard O.,
Racinais S.,
Micallef J.P.,
Millet G. P.
Publication year - 2011
Publication title -
scandinavian journal of medicine and science in sports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.575
H-Index - 115
eISSN - 1600-0838
pISSN - 0905-7188
DOI - 10.1111/j.1600-0838.2009.01032.x
Subject(s) - peripheral , medicine , muscle contraction , contraction (grammar) , electromyography , cardiology , endocrinology , physical medicine and rehabilitation , physical therapy
To examine the time course of alteration in neural process (spinal loop properties) during prolonged tennis playing, 12 competitive players performed a series of neuromuscular tests every 30 min during a 3‐h match protocol. Muscle activation (twitch interpolation) and normalized EMG activity were assessed during maximal voluntary contraction (MVC) of plantar flexors. Spinal reflexes and M‐waves were evoked at rest (i.e., H max and M max , respectively) and during MVC (i.e., H sup , V‐wave, M sup , respectively). MVC torque declined significantly ( P <0.001) across the match protocol, due to decrease ( P <0.001) in muscle activation and in normalized EMG activity. The impairment in MVC was significantly correlated ( r =0.77; P <0.05) with the decline in muscle activation. H max / M max ( P <0.001), H sup / M sup ( P <0.01) and V / M sup ( P <0.05) ratios were depressed with fatigue and decreased by ∼80%, 46% and 61% at the end of exercise, respectively. Simultaneously, peak twitch torque and M‐wave amplitude were significantly ( P <0.01) altered with exercise, suggesting peripheral alterations. During prolonged tennis playing, the compromised voluntary strength capacity is linked to a reduced neural input to the working muscles. This central activation deficit partly results from a modulation in spinal loop properties.