Practical precooling on neuromuscular function and performance in hot and humid conditions

Athletic competition in the heat increases physiological strain and reduces performance during self-paced, endurance exercise. The application of precooling may counteract the negative consequences associated with exercise in hot, humid conditions. 

However at present, there is little evidence establishing whether precooling during an active warm-up alters performance and neuromuscular function during a performance trial. Further, there is limited research examining the application of either an ice vest or cooling packs during a race-specific warm-up, and it remains unclear whether there is a superlative, practical technique. With coaches and athletes needing better guidance on the usefulness of different cooling strategies before endurance running events, more evidence is required to evaluate simple, cost-effective cooling methods.

Project aims

The aim of this research project was to examine the effect of isolated torso and thigh precooling throughout a warm-up on neuromuscular function and five kilometre time-trial performance in hot, humid conditions.  

We hypothesised that torso and thigh precooling would aid running performance during a five kilometre time-trial within a hot environment and minimise neuromuscular fatigue.

Eight well-trained, male club long-distance runners undertook three randomized time-trials in hot, humid conditions.  A 30-min warm-up was completed with no cooling (Control), precooling via an ice vest (Vest), or ice packs covering the thighs (Packs).

Project findings and impact

Torso and thigh precooling during a warm-up reduces thermoregulatory strain.  However, precooling with Packs was the most effective technique to reduce thermoregulatory strain therefore enabling an improved selection of exercise intensities and improved performance during the last kilometre of the five kilometre time-trial.  

Although precooling method neither improves nor inhibits neuromuscular function, it is expected that thigh precooling prevents the down-regulation of exercise intensity evident in hot, humid conditions.

Carla's graph

Figure. 1 Skin temperature during the 5 km time-trial following the 30-min warm-up in the heat with Control, Vest and Packs precooling.

* Significant difference between Control and Vest, P < 0.01.

† Significant difference between Control and Packs, P < 0.01.

‡ Significant difference between Control and Packs, P < 0.05.

§ Significant difference from the start of the warm-up in Packs, P < 0.05. a Control (n = 6). b Control (n = 4), Vest and Packs (n = 6)

Research team

Carla Randall

Dr Emma Ross

Output

Men's Health magazine article (pdf)

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