title: Central Factors Contribute to Knee Extensor Strength Loss after 2000-m Rowing in Elite Male and Female Rowers.
abstract: Despite growing interest in task-dependent alterations of central and peripheral fatigue after endurance exercise, little is known about the effect of rowing on quadriceps muscle fatigue. This study aimed to investigate central and peripheral mechanisms of fatigue after a 2000-m rowing time trial.
  
  
  
  Eight competitive rowers (four males and four females, 20 ± 4 yr) performed a 2000-m time trial on an indoor rower and a control condition (sitting). The neuromuscular function of the knee extensors was analyzed before and 3 min after each experimental condition. Maximal voluntary torque, voluntary activation, and normalized root-mean-square of the EMG signal were measured during isometric and concentric contractions. Furthermore, knee extensor twitch torque and maximal M-wave amplitudes in response to electrical nerve stimulation were assessed.
  
  
  
  After the 2000-m rowing, there were significant reductions in isometric and concentric maximal voluntary torque of the knee extensors (-20% ± 9% and -18% ± 7%, respectively, P < 0.01). Both the voluntary activation of the knee extensors during isometric and concentric contractions decreased by 18% ± 15% (P < 0.05, respectively). The normalized muscle activity of rectus femoris was significantly reduced after rowing (P = 0.007), whereas vastus medialis and vastus lateralis muscle activities did not significantly differ from baseline values. No significant change was observed for knee extensor twitch torque in response to paired electrical stimuli after rowing.
  
  
  
  The 2000-m rowing time trial resulted in significant knee extensor strength loss. Quadriceps muscle fatigue after high-intensity rowing exercise was explained primarily by central factors that lead to large reductions in voluntary drive.
authors: 1Institute of Sport Science, University of Rostock, Rostock, GERMANY; and 2Department of Orthopaedics, University Medicine Rostock, Rostock, GERMANY.
authors: Florian
authors: F
authors: Husmann
authors: Martin
authors: M
authors: Gube
authors: Sabine
authors: S
authors: Felser
authors: Matthias
authors: M
authors: Weippert
authors: Anett
authors: A
authors: Mau-Moeller
authors: Sven
authors: S
authors: Bruhn
authors: Martin
authors: M
authors: Behrens
mesh_terms: D004558:Electric Stimulation; D004576:Electromyography; D019054:Evoked Potentials, Motor / Q000502:physiology; D005260:Female; D005267:Femoral Nerve / Q000502:physiology; D006801:Humans; D007717:Knee / Q000502:physiology*; D008297:Male; D009119:Muscle Contraction / Q000502:physiology; D053580:Muscle Strength / Q000502:physiology*; D052097:Quadriceps Muscle / Q000502:physiology; D013177:Sports / Q000502:physiology*; D019415:Torque; D055815:Young Adult