Predictive Ability of Body Fat Percentage and Thigh Anthropometrics on Tissue Cooling During Cold-Water Immersion

Context: Cold-water immersion (CWI) is a common aid in exercise recovery. The effectiveness of CWI depends on the magnitude of muscle and core cooling. Individual cooling responses to CWI vary and are likely influenced by the CWI dose and individual physiological characteristics. Objective: To evaluate body fat percentage and thigh anthropometric values as predictors of intramuscular and skin-cooling responses to CWI. Design: Descriptive laboratory study. Setting: Sports medicine research center. Patients or Other Participants: Sixteen young adults (8 males, 8 females, age = 24.3 +/- 1.84 years, height = 176.4 +/- 12.7 cm, mass = 86.6 +/- 29.4 kg). Intervention(s): Body fat percentage was measured using a 3-site skinfold assessment. Thigh length, thigh circumference, anterior thigh adipose thickness, anterior thigh muscle thickness, and thigh volume were estimated using manual and ultrasound methods. Using sterile techniques, we placed thermocouple probes in the belly of the rectus femoris (2-cm deep to the subadipose tissue) and on the anterior midthigh surface. Participants cycled on an ergometer for 30 minutes at a target heart rate of 130 to 150 beats/ min. Postexercise, participants were placed in CWI (immersion depth to the iliac crest; 10 degrees C) until intramuscular temperature was 7 degrees C below preexercise baseline temperature, with a maximum immersion duration of 30 minutes. Main Outcome Measure(s): Intramuscular rectus femoris and thigh skin temperatures measured postexercise, after 10 and 15 minutes of CWI, and post-CWI. Results: Body fat percentage significantly predicted the rectus femoris cooling magnitude and rate after 10 minutes of CWI, 15 minutes of CWI, and post-CWI (P < .001; R-2 range = 0.58-0.67). Thigh anthropometric values significantly predicted the thigh skin-cooling rate post-CWI (P = .049; R-2 = 0.46). Conclusions: A simple 3-site skinfold assessment may improve the effective prescription of CWI by allowing estimation of the dose required for minimal muscle tissue cooling.