In essence, tissue flossing creates conditions that are comparable to localized tissue hypoxia, where muscles need to adapt to a lack of oxygen. Although the partial vascular occlusion stimuli used in this study are substantially shorter (3 x 3 minutes) compared to systemic acute hypoxia stimulation, which is usually up to 40 minutes long, there is some evidence that systemic hypoxia actualized via hypoxic chambers can produce similar physiological responses to BFR training \cite{Schoenfeld_2013}. It has been suggested that the excitation of the sarcolemma remains unaffected by systemic hypoxia \cite{Kayser_1993,Rupp_2014}. However, in a study where TMG parameters were used to assess muscle contractile function at acute moderate altitude (hypoxia), an increment of Tc and decrement of Dm was registered \cite{Morales_Artacho_2015}. In a recent study, \citet{Vogrin_2020} investigated the acute effects of a floss band applied over the ankle joint on the TMG parameters of the gastrocnemius medialis muscle but failed to find any statistically significant difference in TMG response. The authors suggested that tissue flossing has a significant but localized effect on the wrapped part of the body.
Similarly, the results of the present study show a significant shortening in RF contraction time (Tc_RF) immediately after tissue flossing intervention in the LOW condition and a medium effect in Dm_RF in favor of the LOW condition compared to CON and HIGH. At the same time, TMG parameters remained virtually unaltered in other muscles (VM and BF) in the CON and HIGH conditions. As proposed by \citet{Wilson_2019}, a shortening Tc and a decrement in Dm parameters can be interpreted as a sign of neuromuscular potentiation. Since potentiation was only observed in RF after the LOW condition, it could be demonstrating that the effect of tissue flossing is precisely localized to the wrapped body area and has a negligible effect on the neuromuscular parameters of muscles distal from the wrapped area.
Moreover, in the present study, the ASLR test remained unaltered, regardless of the wrapping pressure. Even though there were no statistically significant differences, a drop in ASLR 30 minutes after the CON condition compared to LOW is very likely associated with themedium effect recorded. One of the most significant practical implications arising from previous tissue flossing studies where floss band had been applied around the ankle joint, was the enhancement in ankle joint range of motion (ROM) while maintaining, or even increasing, athletic performance \cite{Driller_2017,Driller_2017a}. In contrast, the findings of the present study suggest that when floss band is wrapped around the upper thigh, it has no significant effect on the adjacent joint range of motion (ASLR test remained unchanged). It could suggest that hypoxia and reperfusion may not be the only mechanism inducing ROM improvement after tissue flossing. These findings suggest that there are different mechanisms causing the observed changes in neuromuscular parameters. We can speculate that one possible mechanism could be the stimulation of pressure-sensitive mechanoreceptors in the tissue directly under the wrapped part of the body. The fact that mechano-sensory receptors are more abundant in ankle joint tissue compared to muscles and tendons \cite{Taylor_2009} may explain why ROM improved in ankle wrapping studies but no ASLR improvement was observed in the present study.
The present study might have some limitations. First: although the pressure was individualized according to the literature and controlled using a pressure sensor, there was no insight into the actual blood-flow occlusion created in the affected leg. Furthermore, it was difficult to consistently and accurately apply the floss band in the HIGH condition, resulting in higher deviation from the target pressure. Second: it is difficult to explain why knee flexors were not affected by the floss band since they were partially wrapped as well. Although the floss bands were expertly applied for consistent banding on the front and back of the thigh, pressure sensors were only placed frontally therefore pressure, and thus vascular occlusion, for BF may have been different.