Key result
Very low-load exercise with or without blood flow restriction resulted in greater acute muscle swelling and lower torque (e.g., 28.3 Nm vs 40 Nm; P<0.001) compared to high load exercise.
Why the study?
The study was conducted to examine the acute skeletal muscle response to high-load exercise compared to low-load exercise with and without different levels of applied blood flow restriction.
Does low-load exercise with or without blood flow restriction alter acute skeletal muscle responses compared to high-load exercise?
Does low-load exercise with or without blood flow restriction alter acute skeletal muscle responses compared to high-load exercise?
p-value: p=<0.001
Very low-load exercise (with or without BFR) appears to result in greater acute muscle swelling and greater muscular fatigue compared to high load exercise.
Acute torque deficits after low-load BFR warrant caution before activity; leaves open long-term hypertrophic responses versus high-load.
The purpose was to examine the acute skeletal muscle response to high load exercise and low-load exercise with and without different levels of applied pressure (BFR). A total of 22 participants completed the following four conditions: elbow flexion exercise to failure using a traditional high load [70% 1RM, (7000)], low load [15% 1RM,(1500)], low load with moderate BFR [15%1RM+40%BFR(1540)] or low load with greater BFR [15% 1RM+80%BFR(1580)]. Torque and muscle thickness were measured prior to, immediately post, and 15 min postexercise. Muscle electromyography (EMG) amplitude was measured throughout. Immediately following exercise, the 7000 condition had lower muscle thickness [4·2(1·0)cm] compared to the 1500 [4·4 (1·1)cm], 1540 [4·4(1·1)cm] and 1580 [4·5(1·0)cm] conditions. This continued 15 min post. Immediately following exercise, torque was lower in the 1500 [31·8 (20) Nm], 1540 [28·3(16·9) Nm, P<0·001] and 1580 [29·5 (17) Nm] conditions compared to the 7000 condition [40 (19) Nm]. Fifteen minutes post, 1500 and 1540 conditions demonstrated lower torque compared to the 7000 condition. For the last three repetitions percentage EMG was greater in the 7000 compared to the 1580 condition. Very low-load exercise (with or without BFR) appears to result in greater acute muscle swelling and greater muscular fatigue compared to high load exercise.
No takes yet. Share an insight, caveat, or question.
Buckner et al. (2018) studied this question. Low-load exercise with or without blood flow restriction (BFR) vs. Traditional high load exercise (70% 1RM) was evaluated on Muscle thickness and torque (p=<0.001). Very low-load exercise with or without blood flow restriction resulted in greater acute muscle swelling and lower torque (e.g., 28.3 Nm vs 40 Nm; P<0.001) compared to high load exercise.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: