Effects of blood flow restriction on mechanical properties of the rectus femoris muscle at rest
Authors: Jakub Jarosz 1, Dawid Gawel 1, Michal Krzysztofik 1, Adam Zajac 1, Athanasios Tsoukos 2, Gregory C. Bogdanis 2, Michal Wilk 1
- Institute of Sport Sciences, The Jerzy Kukuczka Academy of Physical Education, Katowice, Poland
- School of Physical Education and Sport Science, National and Kapodistrian University of Athens, Athens, Greece
Journal: Frontiers in Physiology - August 2023, Volume 14, Article no. 1244376 (DOI: 10.3389/fphys.2023.1244376)
Introduction: This study examined the effects of blood flow restriction (BFR) and reperfusion on the mechanical properties of the rectus femoris muscle at rest (frequency and stiffness).
Methods: Fourteen trained men (body weight = 81.0 ± 10.3 kg; BMI = 25 ± 3.0 m/kg2; height = 181 ± 4 cm; training experience = 6.0 ± 2.2 years) participated in an experimental session involving their dominant (BFR) and non-dominant leg (control). Muscle mechanical properties were measured using MyotonPRO’s accelerometer at the midpoint of the rectus femoris muscle at five time points. In the BFR leg, an 80% arterial occlusion pressure was applied by a cuff for 5 min. No cuff was applied in the control leg. Femoral MyotonPROmeasurements were taken from both legs 2 and 4 min after the start of BRF as well as 30 s and 2 min after the end of the occlusion period.
Results: The two-way ANOVA revealed a statistically significant interaction effect for stiffness and frequency (p < 0.001; η2 > 0.67). The post hoc analysis showed that both stiffness and frequency increased during BFR compared with rest and then dropped to the resting levels post BFR period. Also, stiffness and frequency were higher than control only during the BFR period, and similar during rest and post BFR.
Conclusion: These results indicate that the application of BFR at rest leads to significant changes in mechanical properties of the rectus femoris muscle.
Keywords: ischemia, reperfusion, myotonometric assessment, myotonometer, occlusion, stiffness, intramuscular pressure
The results of this study indicate that the application of BFR at rest causes significant changes in mechanical properties of the rectus femoris muscle, i.e., stiffness and frequency. However, this effect is only observed during BFR and disappears immediately after removing BFR. This suggests that BFR increases stiffness and frequency of muscles only during its application, without affecting post-exercise mechanical properties, as assessed by myotonometry.