18. DO PRE-COOLING JACKETS BENEFIT CYCLING PERFORMANCE?

Photo by Jan Antonin Kolar on Unsplash

In previous posts we saw that high ambient temperatures are detrimental for cycling performance. Specifically, we saw data suggesting:

• Pro road cyclists decrease their maximal mean power outputs above 30°C (men) or 25°C (women). (Read more here).

• Power output at first and second ventilatory thresholds (and so training zones) at 35°C are decreased by 10-20% compared to 18°C. (Read more here).

The physiological mechanisms behind the performance decrease in the heat can be:

1. a reduction in the central motor drive to prevent the attainment of dangerous body temperatures

2. an augmented blood flow to the skin for sweating which reduces blood flow to the working muscles.

So, implementing cooling strategies to reduce body temperature can potentially benefit cycling performance in the heat. In the last Tour de France and Vuelta a España, we saw top riders like Jonas Vingegaard, Tadej Pogacar and Tom Pidcock, using pre-cooling jackets before stages with very high temperatures. Are they worth?

Do pre-cooling jackets increase performance in the heat?

If yes, at which temperature does the ergogenic effect start?

A study published by Steve Faulkner and Colleagues on International Journal of Sport Physiology and Performance in 2019 (Environmental Ergonomics Research Centre, Loughborough University, UK) tried to answer these questions. (1).

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WHAT DID THEY DO?

• They recruited 26 trained male cyclists (average VO2max ~60)

• They were split in 3 different groups:

  • 24°C

  • 27°C

  • 35°C

• On two different days, each group performed two time trials (TT) in the lab in two different conditions:

  • Pre-Cooling: they wear a cooling vest and sleeves for 30 min before starting the warm-up and during the 9 min warm-up before TT. The time between end of warm-up (when the cooling garments were taken off) and TT’s start was 5min.

  • Control: with no pre-cooling

The TTs consisted in completing a predetermined amount of work (~1000 kilojoules) as fast as possible, which resulted in ~1-hour efforts. Airflow was fixed at ~10 km/h using a vertical array of three fans.

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WHAT DID THEY FOUND?