Monitoring Lower Leg Blood Flow during Sequential Contrast Therapy Treatments using a Simulated Injury Model

Abstract

Contrast therapy is frequently used to minimize barriers to the normal inflammatory process, but little evidence-based data exists examining the efficacy of this clinical intervention. PURPOSE: Using a simulated injury model (Delayed Onset Muscle Soreness - DOMS), we examined blood flow in the lower leg during warm, cold, contrast, and control (none) treatments. METHODS: Twenty-five female and 15 male volunteers were randomly assigned to the treatment groups (10 per group). Session I was used to determine baseline blood flow, left calf dorsiflexion ROM and pain, blood levels of creatine kinase, and to induce DOMS (calf-raising exercise). Session II involved applying one of the four treatment conditions, during which lower leg blood flow was monitored using strain gauge plethysmography. The percent change in local blood flow (rate of change of limb segment circumference) during each 5-second sampling period served as the dependent variable. The percent change was measured every 15 seconds comparing baseline with each of the measurements in the 3 minute "on-time" phase. RESULTS: Confirming muscle damage, creatine kinase levels were higher post-DOMS, post-DOMS ROM was significantly less than pre-DOMS ROM, and universal pain assessment measures were worse at both 24 and 48 hr. post-DOMS. The ANOVA revealed a significant group x time interaction [F (192, 2304) = 1.227, P =.022]. Blood flow was higher overall in the contrast group as compared to the cold and control groups; while greater fluctuations in blood flow occurred during the time points between transitions from hot to cold and from cold to hot in the contrast group. As expected the warm group had a significantly higher percent change in blood flow as compared to both the cold and control groups. CONCLUSION: It appears that the DOMS induced subjects react to the warm, cold, and contrast treatments much the same way as uninjured subjects from previous reports. Fluctuations in blood flow occurred at the four transitional points in the contrast group and indicate alterations in blood flow are occurring during the sequential contrast treatment scheme. These changes in flow are theorized to benefit healing; and because of the brevity of exposure to either the hot or cold, are most likely the result of localized vasodilation and vasoconstriction, instead of deep vascular changes.