Subcutaneous adipose tissue thickness alters cooling time during cryotherapy

Abstract

Otte JW, Merrick MA, Ingersoll CD, Cordova ML. Subcutaneous adipose tissue thickness alters cooling time during cryotherapy. Arch Phys Med Rehabil 2002;83:1501-5. Objective: To determine if differing subcutaneous adipose thickness alters the treatment duration required to produce a standard cooling effect during cryotherapy. Design: A 4-group, between-groups comparison in which the independent variable was skinfold thickness (0–10mm, 11–20mm, 21–30mm, 31–40mm) and the dependent variable was cooling time, defined as the treatment duration required to decrease intramuscular (IM) temperature 7°C from baseline. Setting: A sports injury research laboratory. Participants: Forty-seven volunteers with anterior thigh skinfold measurement of less than 40mm. Intervention: Topical cryotherapy (750g crushed-ice bag) to the anterior thigh to produce a typical cooling effect, defined as IM temperature at 1cm subadipose declining by 7°C. Main Outcome Measure: Cryotherapy treatment duration required to produce a standardized cooling effect in subjects with differing subcutaneous adipose thickness. Results: Analysis of variance revealed that mean time to cool IM tissues by 7°C differed across all groups, with cooling time increasing as adipose thickness increased. The mean ± standard deviation cooling times were as follows: 31–40mm (58.6±11.7min), 21–30mm (37.8±9.6min), 11–20mm (23.3±6.7min), and 0–10mm (8.0±3.4min). Conclusions: During cold application, there is a clinically important direct relationship between adipose thickness and required cooling time. This relationship necessitates dramatic adjustments to cryotherapy duration to produce similar IM temperature changes. A 25-minute treatment may be adequate for a patient with a skinfold of 20mm or less; however, a 40-minute application is required to produce similar results in a patients with skinfolds between 21 and 30mm, whereas a 60-minute application is required for patients with skinfolds of 30 to 40mm. © 2002 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation