The Association Between Muscle Deoxygenation and Muscle Hypertrophy to Blood Flow Restricted Training Performed at High and Low Loads

Abstract

The metabolic stress induced by blood flow restriction (BFR) during resistance training (RT) might maximize muscle growth. However, it is currently unknown whether metabolic stress are associated with muscle hypertrophy after RT protocols with high- or low load. Therefore, the aim of the study was to compare the effect of high load RT (HL-RT), high load BFR (HL-BFR), and low load BFR (LL-BFR) on deoxyhemoglobin concentration [HHb] (proxy marker of metabolic stress), muscle cross-sectional area (CSA), activation, strength, architecture and edema before (T1), after 5 (T2), and 10 weeks (T3) of training with these protocols. Additionally, we analyzed the occurrence of association between muscle deoxygenation and muscle hypertrophy. Thirty young men were selected and each of participants’ legs was allocated to one of the three experimental protocols in a randomized and balanced way according to quartiles of the baseline CSA and leg extension 1-RM values of the dominant leg. The dynamic maximum strength was measured by 1-RM test and vastus lateralis (VL) muscle cross-sectional area CSA echo intensity (CSA echo ) and pennation angle (PA) were performed through ultrasound images. The measurement of muscle activation by surface electromyography (EMG) and [HHb] through near-infrared spectroscopy (NIRS) of VL were performed during the training session with relative load obtained after the 1-RM, before (T1), after 5 (T2), and 10 weeks (T3) training. The training total volume (TTV) was greater for HL-RT and HL-BFR compared to LL-BFR. There was no difference in 1-RM, CSA, CSA echo, CSA echo /CSA, and PA increases between protocols. Regarding the magnitude of the EMG, the HL-RT and HL-BFR groups showed higher values than and LL-BFR. On the other hand, [HHb] was higher for HL-BFR and LL-BFR. In conclusion, our results suggest that the addition of BFR to exercise contributes to neuromuscular adaptations only when RT is performed with low-load. Furthermore, we found a significant association between the changes in [HHb] (i.e., metabolic stress) and increases in muscle CSA from T2 to T3 only for the LL-BFR, when muscle edema was attenuated.

To Flex or Rest: Does Adding No-Load Isometric Actions to the Inter-Set Rest Period in Resistance Training Enhance Muscular Adaptations? A Randomized-Controlled Trial

“…To ensure that swelling in the muscles from training did not obscure MT results, images were obtained at least 48 h after the training sessions, both in the pre-and poststudy assessment. This is consistent with research showing that acute increases in MT return to baseline within 48 h following an RT session (Ogasawara et al, 2012) and that muscle damage is minimal after repeated exposure to the same exercise stimulus over time (Damas et al, 2016;Biazon et al, 2019). To further ensure accuracy of measurements, three images were obtained for each site and then averaged to obtain a final value.…”

A Systematic Review and Meta-Analysis on Neural Adaptations Following Blood Flow Restriction Training: What We Know and What We Don't Know

“…After checking for eligibility of these articles based on our inclusion and exclusion criteria, 56 studies were excluded. At the final stage, at total of n = 10 studies with n = 232 participants were included in the systematic review ( Table 2 ; Moore et al, 2004 ; Kubo et al, 2006 ; Manimmanakorn et al, 2013 ; Colomer-Poveda et al, 2017 ; Sousa et al, 2017 ; Cook et al, 2018 ; Biazon et al, 2019 ; de Castro et al, 2019 ; Hill et al, 2020 ; Ramis et al, 2020 ).…”

Differential muscle hypertrophy and edema responses between high‐load and low‐load exercise with blood flow restriction

“…This notion is further supported by the absence of change in FSE‐STIR of each muscle, as well as by the lack of alterations in the indirect muscle damage markers collected in the current study (ROM and SOR). Curiously, in a recent study, Biazon et al found increased echo intensity after 5 weeks of LL‐BFR training suggesting some degree of muscle edema/damage. However, it should be mentioned that, different from the present study, their training protocol applied a higher number of repetitions with lower and non‐continuous BFR pressure.…”

“…Studies investigating whether LL‐BFR results in increased muscle damage have produced conflicting findings. While some studies have shown significant increases in muscle damage indicators, others do not demonstrate significant changes . Discrepancies in the literature potentially can be explained by the differences in the employed LL‐BFR protocols between studies.…”

“…Additionally, LL‐BFR has demonstrated significant gains in muscle mass when performed more frequently (every day or twice daily) over a period of 1‐3 weeks . However, while some studies report significant increases in muscle damage markers with LL‐BFR, other studies do not observe significant changes . This discrepancy in the literature can be explained by differences in LL‐BFR protocols used in the studies, suggesting that less fatiguing protocols do not result in muscle damage.…”