Introduction
Tissue flossing has become an increasingly popular technique among
physiotherapists and strength and conditioning specialists, mostly used
as a rehabilitation or performance enhancing
tool\cite{Driller_2017}.
The method consists of tightly wrapping part of a limb or a joint with a
1 to 2 mm thick elastic band, causing partial vascular occlusion of the
blood flow distal to the wrapped area.
Despite the popularity of this method, the acute effects of tissue
flossing on neuromuscular functions are still poorly understood;
moreover, at the time of writing this paper, there was limited
scientific evidence underlying the efficiency of this method. The
majority of published studies have investigated the effects of tissue
flossing applied to the ankle joint, which resulted in increased ankle
range of motion
(ROM) \cite{Vogrin_2020},
increased jump and sprinting
ability \cite{Driller_2017,Driller_2017a}.
On the other hand, only two peer-reviewed studies have investigated the
effects of tissue flossing around a limb (thigh and upper-arm). Both the
aforementioned studies investigated the effects of tissue flossing as a
treatment for delayed onset of muscle soreness (DOMS), leading to
conflicting results: in the study conducted by \citet{Prill_2019},
tissue flossing resulted in lower effectiveness than other gold standard
methods to alleviate the effects of DOMS. However, the authors advocated
that tissue flossing is a valid, practical and cost-effective method. In
contrast, \citet{Gorny_2018} applied three sets of two-minute tissue flossing to the upper-thigh
region after an exercise-induced muscle damaging protocol, finding that
tissue flossing has no effects on DOMS reduction.
Although there are no available studies directly comparing tissue
flossing with ischemic preconditioning/blood flow restriction (BFR)
training, there are similarities between the
methods \cite{Driller_2017}.
Similar to tissue flossing, BFR training consists of complete occlusion
of venous and partial occlusion of arterial blood flow to a limb using
an elastic
wrap \cite{Loenneke_2009} or a specialized inflatable
cuff \cite{Takano_2005}.
There is strong evidence in the literature showing the positive effects
of low-load BFR training on chronic neuro-muscular
adaptations \cite{Fahs_2014,Loenneke_2014,Scott_2014,Takarada2002}.
On the other hand, there is evidence in the literature that single
low-load BFR training sessions acutely decrease neuromuscular
performance \cite{COOK_2013,HUSMANN_2018,Sieljacks_2015},
although \citet{Girard_2019} failed to find such differences during a multi-set resistance exercise
leading to volitional failure in diverse conditions of systemic hypoxia,
BFR, or normoxia. Divergence in the literature arises from differences
in protocols, in particular, in the use of different restrictive
pressures. Some
authors \cite{Scott_2014a} have proposed cuff pressure individualization to achieve more reliable
results. Indeed, \citet{Loenneke_2015} and \citet{Fatela_2016} demonstrated that different relative blood flow occlusions result in
different neuromuscular impairments.
To our knowledge, there are no studies in the literature investigating
the effect of tissue flossing around a limb on neuromuscular
performance. Moreover, a fixed apriori-defined high wrapping pressure
(approx. >180 mmHg) was used in the majority of previous
tissue flossing
studies \cite{Driller_2017,Vogrin_2020,Driller_2017a,Mills_2020}.
Therefore, the aim of this study was to investigate the acute effects of
tissue flossing applied over the upper-thigh region by using different
degrees of wrapping pressure on Active straight leg raise test, maximum
voluntary contraction, and the contractile characteristics of knee
extensors and flexors assessed using tensiomyography.
Methods
Study design
The present study followed a cross-over repeated measures design. Each
subject was exposed to three similar intervention protocols, one per
visit. At each visit, following warm-up and pretest assessments, the
upper-thigh of the dominant leg was wrapped using a rubber elastic band
(floss band), with subjects being instructed to perform active knee
extension and flexion movements. The pressure used to wrap the band was
individualized to each subjects’ thigh circumference and was different
on each visit according to the selected protocol (CON, LOW, HIGH).
During each visit, comprising pre (PRE), immediately after (POST) and 30
minutes after (POST30) applying the floss band, participants performed
several lower-leg assessments in the following order: i) Active straight
leg raise test (ASLR); ii) TMG of the rectus femoris (RF), vastus
medialis (VM) and biceps femoris (BF) muscles; iii) maximum voluntary
contractions of knee extensors and flexors - MVC (see Figure \ref{975321}). There
were at least 48-hours of delay between consecutive visits to avoid
between-session influences.