Low-intensity exercise with blood flow restriction induced greater decrements in the slope between motor unit recruitment threshold and firing rate than exercise without BFR (-165.1% vs -44.4%, p<0.05).
Does blood flow restriction alter motor unit behavior during low-intensity resistance exercise in men?
Low-intensity exercise with blood flow restriction increases the activity of motor units with higher action potential amplitudes and firing rates compared to exercise without restriction.
Absolute Event Rate: -165.1% vs -44.4%
p-value: p=<0.05
We aimed to determine whether blood flow restriction (BFR) alters the characteristics of individual motor units during low-intensity (LI) exercise. Eight men (26.0±3.8 yrs) performed 5 sets of 15 knee extensions at 20% of one-repetition maximum (with and without BFR). Maximal isometric voluntary contractions (MVC) were performed before and after exercise to quantify force decrement. Submaximal isometric voluntary contractions were additionally performed for 18 s, matching trapezoidal target-force trajectories at 40% pre-MVC. EMG activity was recorded from the vastus lateralis muscle. Then, signals were decomposed to extract motor unit recruitment threshold, firing rates and action potential amplitudes (MUAP). Force decrement was only seen after LI BFR exercise (-20.5%; p<0.05). LI BFR exercise also induced greater decrements in the linear slope coefficient of the regression lines between motor unit recruitment threshold and firing rate (BFR: -165.1±120.4 vs. non-BFR: -44.4±33.1%, p<0.05). Finally, there was a notable shift towards higher values of firing rate and MUAP amplitude post-LI BFR exercise. Taken together, our data indicate that LI BFR exercise increases the activity of motor units with higher MUAP amplitude. They also indicate that motor units with similar MUAP amplitudes become activated at higher firing rates post-LI BFR exercise.
Fatela et al. (Wed,) reported a other. Blood flow restriction (BFR) vs. Low-intensity exercise without BFR was evaluated on Decrements in the linear slope coefficient of the regression lines between motor unit recruitment threshold and firing rate (p=<0.05). Low-intensity exercise with blood flow restriction induced greater decrements in the slope between motor unit recruitment threshold and firing rate than exercise without BFR (-165.1% vs -44.4%, p<0.05).
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: