Cooling vests by Cozy winters |
The researchers had their runners complete three randomized 5 km time trials on a treadmill in a laboratory at about 90 degrees Fahrenheit (about 32.2 degrees Celsius) and close to 50 percent humidity.
The runners did a 30 minute warmup consisting of jogging, static and dynamic stretches, more jogging and some short strides to finish.
One group of runners did warmup with an ice vest and another with ice packs covering the thighs (the researchers developed shorts with pockets on the front and back of each high to hold frozen gel packs). The third group was a control group with no cooling devices.
The runners' core and skin temperature, heart rates, perceived rates of exertions were measured during the time trials. Runners with ice packs on their thighs ran the 5 km 85 seconds faster than the control group. Those with the ice vests ran 45 seconds quicker than the control group.
The 5 km times in the study were a lot slower than the runners' own personal bests (19:30 on average compared to 23:45 min after the thigh pre cooling). The authors suggested that this was due to the hot conditions, the fact that the runners could control their pace on the treadmill and that they were not in a race environment.
The authors suggested improvements even in cooler conditions, down to 70 degrees Fahrenheit (or 21.1 Celsius).
The authors cautioned that not everyone will shave 85 seconds off their 5 km race times if you employ such a strategy before your next race in the heat, but there will be some level of benefit.
This study is unique as the runners performed an active, sport specific warmup before the race to mimic what runners actually do before a race.
The authors suggest using an elastic bandage over frozen gel packs on your thighs as an alternative to ice shorts or vests.
Oh, and remember to drink a slushie too.
Reference
Randall CA, Ross EZ et al (2015). Effect Of Practical Precooling On Neuromuscular Function And 5-km Time-trial Performance In Hot, Humid Conditions Amonh Well-trained Male Runners. J Strength Cond Research. 29(7): 1925-1936. DOI: 10.1519/JSC.0000000000000840.
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