The effect of head and neck per-cooling on neuromuscular fatigue following exercise in the heat.
The effect of localised head and neck per-cooling on central and peripheral fatigue during high thermal strain was investigated. Fourteen participants cycled for 60 min at 50% peak oxygen uptake on 3 occasions: thermoneutral control (CON; 18 °C), hot (HOT; 35 °C), and HOT with head and neck cooling (HOTcooling). Maximal voluntary force (MVF) and central activation ratio (CAR) of the knee extensors were measured every 30 s during a sustained maximal voluntary contraction (MVC). Triplet peak force was measured following cycling, before and after the MVC. Rectal temperatures were higher in HOTcooling (39.2 ± 0.6 °C) and HOT (39.3 ± 0.5 °C) than CON (38.1 ± 0.3 °C; P < 0.05). Head and neck thermal sensation was similar in HOTcooling (4.2 ± 1.4) and CON (4.4 ± 0.9; P > 0.05) but lower than HOT (5.9 ± 1.5; P < 0.05). MVF and CAR were lower in HOT than CON throughout the MVC (P < 0.05). MVF and CAR were also lower in HOTcooling than CON at 5, 60, and 120 s, but similar at 30 and 90 s into the MVC (P > 0.05). Furthermore, they were greater in HOTcooling than HOT at 30 s, whilst triplet peak force was preserved in HOT after MVC. These results provide evidence that central fatigue following exercise in the heat is partially attenuated with head and neck cooling, which may be at the expense of greater peripheral fatigue. Novelty Central fatigue was greatest during hyperthermia. Head and neck cooling partially attenuated the greater central fatigue in the heat. Per-cooling led to more voluntary force production and more peripheral fatigue.
['Gordon|Ralph Joseph Frederick Hills|RJFH|', 'Tillin|Neale Anthony|NA|', 'Tyler|Christopher James|CJ|']
D000328:Adult D003080:Cold Temperature D004576:Electromyography D015444:Exercise D006257:Head D006358:Hot Temperature D006801:Humans D047908:Intracellular Signaling Peptides and Proteins D007537:Isometric Contraction D008297:Male D018763:Muscle Fatigue D017346:Protein Serine-Threonine Kinases D055815:Young Adult
exercise peripheral fatigue cooling central activation maximal voluntary contraction hyperthermia activation centrale contraction volontaire maximale exercice fatigue périphérique hyperthermie refroidissement