Effects of vapocoolants on passive hip flexion in healthy subjects.

Vapocoolants have been documented clinically to increase range of motion limited by pain, but only one research study has been undertaken to investigate these observations. The purposes of this study were twofold: to replicate one existing quantitative study on Fluori-Methane Spray and to examine the effects of other brief, cold stimuli (ethyl chloride and isopropyl alcohol) to increase passive hip flexion in healthy adults. Three experimental groups and a control group were used; each subject served as his own control. Pretest and posttest measurements of passive hip flexion were measured in a gravity-minimized position. A specially designed table to ensure trunk stabilization was used. Brief, cold stimuli applied to the posterior region of the thigh were found ineffective in increasing passive hip flexion in healthy adults. The rationale for the findings is described in terms of the effects of brief, cold stimuli on a quiescent CNS as opposed to a CNS demonstrating heightened excitability in the pain-spasm-pain cycle.