Effect of limb circumference on intramuscular cooling during and following an ice bag application after exercise

Context: Ice bags are commonly applied following exercise, but the effect of limb size on cooling duration and rewarming has not been documented. Objective: Investigate the effect of limb circumference on cooling duration to 10°C below resting baseline and examine the subsequent rewarming trends. Design: Two separate designs were used: a 1 X 2 cross-over design on limb circumference (large circumference [LC: 58-63.5cm] and small circumference [SC: 50-54cm]) and duration of treatment (time to 10°C below baseline) and a 2 X 7 cross-over design on the two limb circumference groups (LC and SC) and the rewarming trend at time Imd, 10-, 20-, 30-, 40-, 50-, and 60-minute. Setting: Laboratory Patients or Other Participants: Fourteen physically active, healthy, college-aged volunteers (20.8 ± 2.7y, ht: 174.6 ± 5.7cm, mass: 75.8 ± 11.9kg: skinfold: 17.9 ± 4.1mm). Interventions: Comparison of LC and SC limbs Main Outcome Measure(s): Duration to 10°C below baseline at 2-cm subadipose tissue depth of the midpoint of the quadriceps and temperature of rewarming at time Imd., 10-, 20-, 30-, 40-, 50-, and 60-minute. Two separate analyses were performed: a 1 X 2 crossover design for duration and a 2 X 7 crossover design for rewarming and Tukey-Kramer MC tests were used for the rewarming. Alpha was set a priori at 0.05. Results: The LC limbs took 6.5min. longer (P = 0.02) to cool than the SC limbs (45min). There was an interaction of circumference and time on temperature (P =.004) with SC limbs being cooler at each time period except Imd. Conclusions: LC limbs took longer to cool to 10°C below baseline. LC limbs remained at the target temperature for 20 minutes while SC limbs continued to cool before warming past the target temperature at 40 minutes. Limb circumference influences treatment duration and rewarming trends