Augmented supraspinal fatigue following constant-load cycling in the heat

Research output: Contribution to journalArticle

  • Stuart Goodall
  • Kayleigh Charlton
  • C. Hignett
  • Jonathan Prichard
  • Martin Barwood
  • Glyn Howatson
  • Kevin Thomas
Original languageEnglish
Pages (from-to)164-172
Number of pages9
JournalScandinavian Journal of Medicine and Science in Sports
Volume25
Issue numberS1
DOIs
Publication statusPublished - Jun 2015
Externally publishedYes
The development of central fatigue is prominent following exercise-induced hyperthermia, but the contribution of supraspinal fatigue is not well understood. Seven endurance-trained cyclists (mean ± SD peak O2 uptake, 62.0 ± 5.6 mL/kg/min) completed two high-intensity constant-load cycling trials (296 ± 34 W) to the limit of tolerance in a hot (34°C, 20% relative humidity) and, on a separate occasion, for the same duration, a control condition (18°C, 20% relative humidity). Core body temperature (Tc) was measured throughout. Before and immediately after each trial, twitch responses to supramaximal femoral nerve and transcranial magnetic stimulation were obtained from the knee extensors to assess neuromuscular and corticospinal function, respectively. Exercise time was 11.4 ± 2.6 min. Peak Tc was higher in the hot compared with control (38.36 ± 0.43°C vs 37.86 ± 0.36°C; P=0.035). Post-exercise reductions in maximal voluntary contraction force (13 ±9% vs 9 ± 5%), potentiated twitch force (16 ± 12% vs 21 ± 13%) and voluntary activation (9 ± 7% vs 7 ± 7%) were similar in hot and control trials, respectively. However, cortical voluntary activation declined more in the hot compared with the control (8 ± 3% vs 3 ± 2%; P=0.001). Exercise-induced hyperthermia elicits significant central fatigue of which a large portion can be attributed to supraspinal fatigue. These data indicate that performance decrements in the heat might initially originate in the brain.

    Research areas

  • Brain, exercise, hyperthermia, performance

External organisations

  • Northumbria University

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