Effects of environmental cooling on force production in the quadriceps and hamstrings.

The purpose of this study was to determine the effects of environmental cooling on force production in the quadriceps and hamstring muscles. Ten men (mean +/- SD: age = 21.4 +/- 2.2 years, height = 168.5 +/- 35.9 cm, body mass = 78.0 +/- 6.4 kg) participated in this study. Each subject completed 2 sets of 10 maximal effort repetitions on a Cybex II isokinetic dynamometer at 3.14 rad x s(-1). Between sets, subjects sat in environmental temperatures of 20, 15, 10, or 5 degrees C for 40 minutes. A significant decrease (p </= 0.05) was observed in the pre- to postcooling peak torque values at 10 degrees C and 5 degrees C for both quadriceps and hamstrings. A significant decrease (p </= 0.05) was also observed in the pre- to postcooling average torque values for the hamstrings at 10 degrees C and 5 degrees C. A significant increase (p </= 0.05) in the amount of heat loss from the quadriceps and hamstrings occurred as environmental temperatures decreased. Force production of the quadriceps and hamstrings is significantly decreased when the body experiences environmental temperatures at or below 10 degrees C for at least 40 minutes. A significant amount of heat loss also occurred from the quadriceps and hamstrings as environmental temperature decreased. The take-home message is that after a certain period of time exposed to cool ambient temperatures, performance may be decreased and warm-up time will increase.