OBJECTIVE: To investigate the relationship between the amount of overlying adipose and intramuscular temperature change during and after a 20-minute crushed-ice pack treatment. DESIGN AND SETTING: Subjects were divided into 3 equal groups according to calf skinfold thickness: 8 mm or less, 10 to 18 mm, and 20 mm or greater. Intramuscular temperature was monitored at 1 cm and 3 cm below the subcutaneous fat in the left medial calf during and after a 1.8-kg crushed-ice pack treatment. SUBJECTS: Thirty uninjured college students volunteered to be subjects. MEASUREMENTS: Intramuscular temperature was recorded every 10 seconds over a 20-minute treatment and for 30 minutes posttreatment. RESULTS: Intramuscular temperature decreases between adipose groups at the end of treatment at both 1 cm and 3 cm below the subcutaneous fat were significantly different. At 1 cm within the muscle, the temperature decreases were 14.43 degrees C, 9.06 degrees C, and 5.00 degrees C for 8-mm or less, 10- to 18-mm, and 20-mm or greater skinfolds, respectively. At 3 cm, temperatures were 6.22 degrees C, 3.86 degrees C, and 2.42 degrees C, respectively. By 30 minutes posttreatment at 1 cm, the 8-mm or less and 10- to 18-mm groups rewarmed 5.39 degrees C and 2.22 degrees C, respectively, but the 20-mm or greater group was 0.49 degrees C colder than at the conclusion of the treatment. At 3 cm, temperatures in all 3 groups were colder at 30 minutes posttreatment than they were at the end of the treatment, 1.63 degrees C, 1.83 degrees C, and 2.10 degrees C for 8-mm or less, 10- to 18-mm, and 20-mm or greater skinfolds, respectively. CONCLUSIONS: The amount of adipose over the therapy site is a significant factor in the extent of intramuscular temperature change that occurs during and after cryotherapy. Adipose should, therefore, be taken into account in determining appropriate treatment protocols.