The Effects Of Different Blood Flow Restriction Cuff Pressures On Dynamic Knee Valgus Angles

Abstract

PURPOSE: To examine the effects of two different Blood Flow Restriction (BFR) cuff pressures after three weeks of cycle training on knee stability, specifically dynamic knee valgus (DKV) angles on healthy adults. METHODS: Ten healthy participants (26 ± 3 years; 6 males; 4 females) were randomized to: BFR with 60% occlusion, and BFR with 80% occlusion while cycling in an ergometer for 15 minutes at 70 rpm, three times a week for three weeks. Knee stability was measured during a three 5-repetition single-leg step down per leg, for the right leg, from a 30-centimeter firm and stable platform. Participants were given one minute of rest between trials to prevent fatigue. The average knee valgus among trials was used for analysis. Valgus motion was tracked through a 10-camera motion analysis capture system (120 Hz sampling rate). Valgus was measured at the lowest achievable depth of the step down. Comparison of valgus angles were done at baseline and at three weeks. Given normally distributed data, a 2 x 2 (group by time) ANOVA was used to perform between and within-group comparisons. Statistical significance was set at an alpha of 0.05 for all comparisons. RESULTS: Although the 80% occlusion group reduced knee valgus by 2.8 degrees, between and within-group comparisons were not statistically significant for DKV. CONCLUSIONS: It appears at this point that cycling with BFR cuffs does not alter knee stability in weight bearing conditions for healthy individuals. This lack of effectiveness could be due to the short time frame between baseline and follow-up or a bigger sample size will be needed to find statistically significant differences. Future research should complement treatment techniques design to improve knee stability with BFR to explore the effects of combined interventions.