title: Neural and muscular adjustments following repeated running sprints.
abstract: This study aimed to reveal the neural and muscular adjustments following a repeated-sprint (RS) running exercise. Sixteen subjects performed a series of neuromuscular tests before, immediately after and 30 min (passive recovery) post-RS exercise (12 x 40 m sprints interspaced by 30 s of passive recovery). Sprint times significantly lengthened over repetitions (+17% from the first to the last sprint; P < 0.05). After RS running exercise, maximal voluntary contraction torque of the plantar flexors (-11 +/- 7.3%), muscle activation (twitch interpolation) (-2.7 +/- 3.4%) and soleus maximal M-wave amplitude (-20 +/- 17%) were significantly (P < 0.05) reduced but returned close to baseline after 30 min. Both soleus EMG activity and maximal Hoffmann reflex normalized with respect to M-wave amplitude did not change during the whole experiment. From pre- to post-RS exercise, evoked twitch response was characterized by lower peak torque and maximal rate of torque development (-13 and -11%, respectively, P < 0.05), but was not different from baseline after recovery. Peak tetanus at 20 and 80 Hz were 17 and 8% lower (P < 0.05) in the fatigued state, respectively. Acute muscle fatigue induced by RS running exercise is mainly peripheral as the short-term (30 min) recovery pattern of plantar flexors contractile properties follows that of the voluntary force-generating capacity.
authors.affiliation: Laboratoire EA 2991 Efficience et Déficience Motrices, UFR STAPS, Faculté des Sciences du Sports, Université Montpellier 1, 700 Avenue du Pic Saint Loup, 34090, Montpellier, France. stephane.perrey@univ-montp1.fr
authors.forename: Stéphane
authors.initials: S
authors.lastname: Perrey
authors.forename: Sébastien
authors.initials: S
authors.lastname: Racinais
authors.forename: Khaled
authors.initials: K
authors.lastname: Saimouaa
authors.forename: Olivier
authors.initials: O
authors.lastname: Girard
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology; D000328:Adult; D006801:Humans; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D018763:Muscle Fatigue / Q000502:physiology*; D018482:Muscle, Skeletal / Q000294:innervation / Q000502:physiology*; D005082:Physical Exertion / Q000502:physiology*; D012026:Reflex, Stretch / Q000502:physiology*; D012420:Running / Q000502:physiology*