The acute response of practical occlusion in the knee extensors

Training at low intensities with moderate vascular occlusion results in increased muscle hypertrophy, strength, and endurance. Elastic knee wraps, applied to the proximal portion of the target muscle, might elicit a stimulus similar to the KAATSU Master Apparatus. The purpose of this study was to test the hypothesis that intermittently occluding the leg extensors with elastic knee wraps would increase whole-blood lactate (WBL) over control (CON). Twelve healthy men and women participated in this study (age 21.2 ± 0.35 years, height 168.9 ± 2.60 cm, and body mass 71.2 ± 4.16 kg). One repetition maximum (1RM) testing for the leg extensors was performed on a leg extension machine for the first trial, followed by occlusion (OCC) and CON trials. Four sets of leg extension exercise (30-15-15-15) were completed with 150-second rest between sets at 30% 1RM. Whole-blood lactate, heart rate (HR), and ratings of perceived exertion (RPEs) were measured after every set of exercise and 3 minutes postexercise. Data were analyzed using repeated-measures analysis of variance with statistical significance set at p ≤ 0.05. Whole-blood lactate increased in response to exercise (p = 0.01) but was not different between groups (OCC 6.28 ± 0.66 vs. CON 5.35 ± 0.36 mmol·L, p = 0.051). Heart rate (OCC 128.86 ± 4.37 vs. CON 119.72 ± 4.10 b·min?1) was higher with OCC from sets 2-4 (p ≤ 0.03), with no difference 3 minutes postexercise (p = 0.29). Rating of perceived exertion was higher with OCC after every set (OCC 15.10 ± 0.31 vs. CON 12.16 ± 0.50, p = 0.01). In conclusion, no differences exist for WBL between groups, although there was a trend for higher levels with OCC. The current protocol for practical occlusion did not significantly increase metabolic stress more than normal low-intensity exercise. This study does not support the use of knee wraps as a mode of blood-flow restriction.