title: Etiology of Neuromuscular Fatigue After Repeated Sprints Depends on Exercise Modality.
abstract: OBJECTIVE
  To compare neuromuscular fatigue induced by repeated-sprint running vs cycling.
  
  
  METHODS
  Eleven active male participants performed 2 repeated-maximal-sprint protocols (5×6 s, 24-s rest periods, 4 sets, 3 min between sets), 1 in running (treadmill) and 1 in cycling (cycle ergometer). Neuromuscular function, evaluated before (PRE); 30 s after the first (S1), the second (S2), and the last set (LAST); and 5 min after the last set (POST5) determined the knee-extensor maximal voluntary torque (MVC); voluntary activation (VA); single-twitch (Tw), high- (Db100), and low- (Db10) frequency torque; and maximal muscle compound action potential (M-wave) amplitude and duration of vastus lateralis.
  
  
  RESULTS
  Peak power output decreased from 14.6 ± 2.2 to 12.4 ± 2.5 W/kg in cycling (P < .01) and from 21.4 ± 2.6 to 15.2 ± 2.6 W/kg in running (P < .001). MVC declined significantly from S1 in running but only from LAST in cycling. VA decreased after S2 (~-7%, P < .05) and LAST (~-9%, P < .01) set in repeated-sprint running and did not change in cycling. Tw, Db100, and Db10/Db100 decreased to a similar extent in both protocols (all P < .001 post-LAST). Both protocols induced a similar level of peripheral fatigue (ie, low-frequency peripheral fatigue, no changes in M-wave characteristics), while underlying mechanisms probably differed. Central fatigue was found only after running.
  
  
  CONCLUSIONS
  Findings about neuromuscular fatigue resulting from RS cycling cannot be transferred to RS running.
authors.forename: Katja
authors.initials: K
authors.lastname: Tomazin
authors.forename: Jean-Benoit
authors.initials: JB
authors.lastname: Morin
authors.forename: Guillaume Y
authors.initials: GY
authors.lastname: Millet
mesh_terms: D000328:Adult; D001642:Bicycling / Q000502:physiology*; D004558:Electric Stimulation; D004576:Electromyography; D016552:Ergometry; D015444:Exercise; D005267:Femoral Nerve / Q000502:physiology; D006801:Humans; D007537:Isometric Contraction; D008297:Male; D018763:Muscle Fatigue; D052097:Quadriceps Muscle / Q000502:physiology; D012420:Running / Q000502:physiology*; D019415:Torque; D055815:Young Adult
keywords: central fatigue; motorized treadmill; peripheral fatigue; stretch-shortening cycle