Muscle activation during horizontal leg press at different blood flow restriction pressures

Area of Science:

• Exercise Physiology
• Biomechanics
• Muscle Physiology

Background:

• Blood flow restriction (BFR) training is increasingly used to enhance muscle adaptation.
• Understanding the impact of varying BFR pressures on muscle activation during resistance exercise is crucial for optimizing training protocols.
• Low-intensity exercise with BFR is an area of interest for potentially achieving hypertrophic and strength gains with reduced joint stress.

Purpose of the Study:

• To compare muscle activation during leg press exercise under different blood flow restriction (BFR) pressure percentages (30%, 50%, 80%) versus no restriction.
• To investigate the effects of BFR at varying intensities on muscle activity during low-load, high-repetition leg press.
• To determine if different BFR pressures influence the electromyographic (EMG) activity of the quadriceps muscles (rectus femoris, vastus lateralis, vastus medialis).

Main Methods:

• Sixteen sedentary young men performed randomized leg press sessions (4 sets of 15 reps at 40% of 1RM).
• Experimental conditions included no BFR and BFR at 30%, 50%, and 80% of maximal occlusion pressure.
• Surface electromyography (sEMG) recorded activity of rectus femoris, vastus lateralis, and vastus medialis, normalized using the dynamic peak RMS method.

Main Results:

• Electromyographic (EMG) activity showed significant differences between sets for VM (Set 3 > Set 1) and RF (Set 1 > Set 2) at 50% BFR.
• No significant differences in muscle activation were found between the various BFR pressure percentages and the no-restriction condition.
• Overall, muscle activation patterns were similar across all tested BFR intensities and the control condition during the leg press exercise.

Conclusions:

• Similar muscle activation levels were observed between leg press exercise performed with and without varying percentages of blood flow restriction at the same low intensity.
• The application of different BFR pressures (30%, 50%, 80%) did not lead to significantly different muscle activation compared to the non-restricted condition.
• These findings suggest that at this specific low intensity and volume, BFR may not substantially alter the neuromuscular recruitment patterns during the leg press exercise.