Comparison of neuromuscular responses to blood flow restriction and ice application during maximal effort knee extension and flexion: a randomized, controlled, crossover trial

The purpose of this study was to determine the acute effects of blood flow restriction (BFR) and ice application on muscular performance and neuromuscular recruitment during sets of maximal effort leg extension and flexion on an isokinetic dynamometer. Fifteen resistance trained individuals (age: 23.9 ± 4.8 years, wt: 79 ± 12.6 kg, ht: 175.7 ± 10.4 cm) performed 5 sets of 5 maximal effort knee extensions and flexions with both legs on an isokinetic dynamometer with electromyography under three conditions: control (CON), ice application (ICE), and BFR (80% personal occlusion pressure). Repeated measures ANOVA was used to assess between conditions and sets for peak torque (PT), work per rep (WK), average power per rep (PWR), and root mean square (RMS) muscle recruitment values. No differences were detected between conditions; however, CON produced the lowest muscle recruitment with differences being observed between set averages for RMS values in the right ( p < 0.001) and left ( p = 0.005) legs and in condition × set interaction for RMS values in the right ( p = 0.006) and left ( p = 0.11). BFR produced the lowest mechanical outputs with both leg extensions displaying differences in the condition × set interaction for PT, WK, and PWR ( p < 0.05). Right flexion differences were observed for condition, set, and the condition × set interaction for PT, WK, and PWR ( p < 0.05). Left flexion displayed differences in the condition × set interaction for PT, WK, and PWR ( p < 0.05). The application of BFR during maximal leg contractions results in similar muscle activation and decreased mechanical output compared to CON and ICE conditions.