The Effect of Tissue Flossing Technique on Sports and Injury Prevention and Rehabilitation: A Systematic Review of Recent Research

The of Flossing Abstract Flossband, as a novel and effective tissue flossing technique, is becoming increasingly popular in the field of athletic training, sports injury prevention, and rehabilitation. The purpose of this literature review is to summarize updated evidence about the effects of flossband application on joint range of motion (ROM), pain, muscle tightness, strength, and physical functional performance as well as identify research gaps for future study. Google Scholar, PubMed, EBSCO, and Web of Science were used to search related articles. The keywords of floss bands, flossbands, floss band, tissue flossing, flossing band, voodoo floss band, voodoo floss bands, track floss, rock floss, life floss band, and Rogue voodoo floss were used to extract target articles. English journal articles, full-text available, and content related to outcome measures were included. Conference abstracts, books, case studies, guideline reviews were omitted. 23 full-text journal articles were included for further qualitative analysis after removing duplicates and deleting articles that violate the screening criterion. Flossband application on limbs, soft tissue, or joints with about 50% flossing tension or 150 mmHg wrapping pressure could have small to medium effects on the parameters of ROM, muscle stiffness, muscle strength, and physical function performance, and large effects on pain management. Most previous studies were mainly focused on the acute effect of flossband application on peripheral joints or soft tissues in healthy and active participants or well-trained athletes. Therefore, for future studies, more evidence is needed on the benefits of long-term flossband trunk application and concerning patients with various diseases.


Introduction
High-energy sports are prone to sports injuries as a result of tissues being overused during intense sports activities. Repeated exposure to the high mechanical stresses associated with sporting activities promotes abnormal postural adjustments and myofascial injuries [1]. Inflammatory reactions to tissue injury can change the structure of myofascial tissues, thus causing discomfort and hypersensitivity, and reducing an athlete"s range of motion (ROM), strength and performance [2]. Many therapeutic strategies have been used to prevent and cure 1158 The Effect of Tissue Flossing Technique on Sports and Injury Prevention and Rehabilitation: A Systematic Review of Recent Research sports injuries and dysfunctions caused by biomechanical deficiencies and overuse. A flossband treatment is among the most popular therapeutic interventions in sports [3]. The anecdotal usage of this treatment among athletic individuals is becoming a popular technique to increase joint ROM, enhance both injury prevention and recovery, and improve overall sports performance. The soft tissue flossing technique is a treatment tool and an optional strategy to assist in sports training [4]. A flossband is composed of multiple layers of natural rubber, with a thickness of more than 1 centimeter, and this technique is an easy-to-acquire skill by different occupational professionals [5]. In addition, flossband is cheap, convenient, flexible, and effective [6].
Over the past few years, flossband application has been more commonly used in the field of training or rehabilitation. Accordingly, researchers have concentrated on testing the effects of flossband application on joint ROM in different joints [7,8], muscle tightness [9,10], muscle strength [15,16], as well as physical function performance [8,[11][12][13]. However, despite the apparent benefits found in the above parameters, there was no relevant literature review that integrated these different findings. Wrapping tension or compression pressure of flossband application was the key skill. By reviewing the previous studies, these studies investigated the effects of flossband application by using various flossing tensions or wrapping pressures, such as 50% stretch tension [5,14] and 150-200 mmHg wrapping pressure [15,16] on the different soft tissues or joints. However, they all observed similar outcome measures. Unfortunately, there is little evidence overall for this technique and the current evidence. Very few studies showed either positive or negative support for use of tissue flossing.
To date, several papers have been published about the effects of tissue flossing techniques on the functionality of the hamstring muscles [9], ankle ROM and tensiomyography parameters [16], or the healthy and impaired musculoskeletal system [17]. No such overview exists for the effects of flossing. Thus, an in-depth review on the effects of the tissue flossing method in sports injury prevention and rehabilitation is required. Going forward, the purpose of this literature review was to collect, analyze and summarize the recent research on the application progress of tissue flossing technique, as well as to provide updated evidence about the effects of applying flossing technique on the parameters of pain, joint ROM, muscle tightness and physical functional performance in sports and clinical practice. Moreover, this literature review also aimed to identify potential research areas for future studies on the tissue flossing technique.

Methodology
This review included research studies related to the outcomes of tissue flossing technique application on different peripheral joints and soft tissues in different groups of people, such as general healthy young people, athletes, or patients. Hence, our population consisted of studies across seven years from January 2014 to May 2021.
As part of the search strategy, Google Scholar, PubMed, EBSCO, and Web of Science were used to search the related articles. The keywords of floss bands, flossbands, floss band, tissue flossing, flossing band, voodoo floss band, voodoo floss bands, track floss, rock floss, life floss band, and Rogue voodoo floss were used separately or in combination to extract the target articles ( Table 1). The articles were required to be journal articles that were published in English. Conference abstracts, related books, case studies, guideline reviews, unavailable full text or articles without any relationship to the content by reviewing titles and abstracts were excluded. In addition, articles which did not report the outcome measures of pain, joint range of motion, and functional performance were also omitted.

Study Selection
Two reviewers worked on the task of article searching and article quality evaluation. On one aspect, they individually used the same keywords to search articles in these four search engine databases. Then, they reviewed the title, abstract and full-text articles according to the inclusion and exclusion criteria. Articles were included in this study when the content is about the effects of tissue flossing on different soft tissues and various peripheral joints such as hamstring, upper limb muscles, quadriceps, Achilles tendon, ankle joint, knee joint, shoulder joint, elbow joint, and so on. Additionally, the articles should be focused on the parameters of pain, joint range of motion, muscle tightness, muscle strength, and physical function performance. For the other aspect, the two reviewers independently used methodology checklists which were developed by the Scottish Intercollegiate Guidelines Network (SIGN) (https://www.sign.ac.uk/checklists-and-notes.html) to evaluate the quality of the articles [18].

Results
This research identified 415 related articles in total. Of these, 410 articles were obtained from databases of PubMed, EBSCO, Web of Science, and Google Scholar by using the related keywords and search strategies. In addition, 1 abstract and 4 journal articles were found from other resources. Next, 85 articles were removed due to duplication. After that, 307 articles were excluded because these articles were not in English, had unrelated content, were not journal articles (news, product introduction, advertising, or conference abstracts) or the full-text was unavailable. Finally, 23 full-text journal articles were included for further qualitative analysis by following the exclusion criterion and inclusion criterion through a rigorous screening process (see Figure 1). Table 2 summarizes the results of accessible studies.   Pre-posttest (wrapped flossband, remove flossband immediately test) Test would be executed into two days. In the first day, all participants were accepted CMJ (repeat three times and take the average) and VAS test before formal study, then they were wrapped by flossband around the knee and did the same test, after that they were removed the flossband and did the same test. In the second day, all participants did the same test but without applied flossabnd during three parts of testing. 1-minute rest between series, and 15 seconds between epetitions.
VAS CMJ (jump height, jump velocity, jump power, jump force) There was significant improvement in all outcome measure between pretest and posttest.
There was no significant difference without fossband during the second day testing. Pre-posttest (posttest was test after 5 minutes and after 30 minutes) All participants went through two different trials interval 7 days), one is flossbans trial, and another was control trial (without flossband) 5 minutes" warm-up exercises Flossband session: all participants were asked to seat on the floor with both knee full extension, and they did full range of ankle PF and DF (2 minutes, 2 secs/ each). Flossband was removed, and they were tested after 5 minutes and 30 minutes.
Control session: all particpants did the same exercise but without wrapping flossband. There was significant difference for the low condition between pre and posttest during the knee extensor MVC (post immediately and post 30 minutes), TcRF (post immediately) and TcVM (post 30 minutes). There was no significant difference between groups among these outcomes, but there were medium benefits between low condition and high condition (TcRF and knee extension MVC), low condition and control condition (DmRF), and high condition to control condition (DmBF). Pre-posttest (post5 post15 post30 post45) All participants did 6 minutes" warm-up, then they did the immediate test as the baseline. Random chosen the ankle and applied the flossband, and then they were asked to do active ankle PF and DF on both ankles with knee extension sitting on bed (2 minutes/ set, 3 sets, rest 2 minutes between each set), after complete the ankle exercise, they were instructed to walk around 2 minutes. The posttest conducted after 5, 15, 30 and 45 minutes" intervention.
Active ankle PF and DF ROM, There were significant differences between baseline and posttest (post5 post15 post30 post45) in ankle DF ROM within groups, only ankle PF ROM in flossband group. Kielur     According to the data extracted in this review, it can be assumed that the tissue flossing technique has a positive effect on joint ROM, pain, muscle tightness, muscle strength, and physical function performance (see Table 3).

The Effects of Flossing on Joint Range of Motion
Nineteen out of 23 studies examined the effectiveness of flossband application on the ROM of various joints. Fourteen out of 19 individual studies focused on comparing the effects of flossband application on ankle dorsiflexion of range of motion (DFROM) to other interventions. The findings of these 14 studies show that there was no significant difference during DFROM between the flossband group and the control group, but there was a positive trend [19,24]. However, there was a significant difference of DFROM between the pre-and post-tests in the flossband group [15,20]. Systematic evidence showed that flossband treatment is a useful method to acutely increase the effects of ankle ROM, compared to other methods [30]. Only one out of 19 individual studies wrapped flossband on the upper arm, and the results showed that shoulder flexion was significantly improved [20]. In addition, four out of 19 individual studies proved that flossband application on the thigh could improve knee flexion ROM and hip flexion ROM. Meanwhile, Cheatham, [5] pointed that flossband intervention is more effective than soft tissue mobilization or other types of instruments in the aspect of joint flexibility.

The Effects of Flossing on Pain
Only 1 out of 23 studies investigated the effectiveness of the application of flossband on chronic pain management. In Garcí a-Luna"s [7] pilot study, five young male recreational athletes diagnosed with chronic patellarfemoral pain syndrome (PFPS) were recruited, and all the participants were instructed to do three counter movement jumps (CMJs) with a flossband wrapping above the patellar (with 182±38 mmHg), or without it, during pre-and post-tests for evaluation of the acute effect of variation of knee pain intensity. The results showed that the application of flossband on patients with chronic PFPS was found to significantly decrease the perception of knee pain (Analogue visual scale, VAS) after immediately removing the flossband [7]. However, there was no significant difference in a variety of pain perceptions on the affected knee between the flossband group and the control group.

The Effects of Flossing on Muscle Tightness
Two out of 23 studies examined the acute effect of flossband application on hamstring tightness by comparing the straight leg raise test (SLR). A similar flossband wrapping method, the application on the dominant thigh of healthy participants, was used in these two studies, but different interventions were compared in the aspect of effectiveness of flossband application on muscle tightness. One finding revealed that there was no significant difference in hamstring tightness among the groups (control group with a pressure of less than 20 mmHg, a moderate group with 100 mmHg to 140 mmHg, and high group with 150 mmHg to 210 mmHg), and within the groups (pre, post immediate and post 30 minutes). However, the small to medium improvement of SLR was found between the group with moderate pressure and the control group with low pressure. Small benefits were associated between the application of the flossband with the high pressure and low pressure, and there was a beneficial trend compared to the groups with low and high pressure respectively [27]. Another result showed that there was a significant difference in SLR changes after immediate removal of the flossband compared to the control group. In addition, the flossband as an effective instrument has the same benefit as dynamic stretching in reducing tightness of the hamstring, or it is even more beneficial [25].

The Effects of Flossing on Muscle Strength
Six out of 23 studies compared the acute effect of flossband application on the calf or thigh of healthy participants to improve ankle or knee strength, as well as muscle activation. Four out of 6 individual studies not only reported the effect of flossband application on strength, but it also associated on muscle activation. There was no significant difference of isometric maximal voluntary contraction (IMVC) of ankle plantar flexion force and gastrocnemius (GC) activation among the groups (group with flossband, group with static stretching, and group with resting), but the flossband application on the GC helps improve ankle dorsiflexion rate of force development for the first 100 seconds, compared to the control groups [25]. In addition, flossband application on the thigh has benefits in improving the IMVC of knee extension strength, or eccentric MVC of knee flexion, and increasing neuromuscular activity, compared to the control group [17,25,27]. Two out of 6 individual studies only mentioned flossband application on strength. In Galis" study [24], the result showed that there was no significant difference between the strength of ankle flexion and extension among the groups (control group, group with 150 mmHg flossband wrapping pressure and 200 mmHg flossband wrapping pressure), but flossband wrapping on the calf muscle with 150 mmHg might be beneficial to improve ankle dorsiflexion peak torque (DFPT), compared to the control group and the group with high wrapping pressure [24]. DFPT was improved by up to 22% after flossband application [10]. Thus, flossband seems to be beneficial to enhance muscle strength.

The Effects of Flossing on Physical Function Performance
Ten out of 23 studies examined the acute effect of flossband application on the squat, running, and jumping. Only one out of 10 individual studies compared different interventions on the performance of the body overhead weight squat. The study revealed that squat function was significantly improved after flossband application, but there was no significant difference in squat performance among the groups. Therefore, this result indicated that the flossband seems to be as effective as dynamic stretching with closed-kinematics chain or static stretching with closed-kinematics chain [11]. There are two out of 10 individual studies that compared the time of the 5-meter, 10-meter, and 15-meter sprint performance in healthy athletes between the flossband group and the control group. The results showed that there was an improvement in the 10-meter sprint and 15-meter sprint group compared to the control group, and these benefits will last up to 45 minutes [13,19,31]. Seven out of 10 studies compared the changes in jumping performance between the flossband group and the control group. Five out of 7 studies showed that there was a significant improvement in jump height, jump velocity, jump power, and jump force after applying a flossband. However, there was only an improvement trend between groups [7]. Only two studies presented that there was insufficient evidence about flossband improving jump performance [12]. Therefore, flossband could be a novel method to improve physical function.

Discussion
Flossband as a therapeutic intervention instrument could be used to increase ankle dorsiflexion ROM over the short term and the long term. Furthermore, small to large effect sizes have been found in previous studies. In the field of acute effects of flossband application on the ankle, Driller [19] found that flossband wrapped around the ankle significantly improved ankle dorsiflexion ROM in healthy young athletes. However, these two results were only associated with small effect sizes of 0.21 and 0.31, respectively. In the same year, Hagen"s study [11] showed similar evidence about flossband significantly improving ankle dorsiflexion ROM in healthy college students (d = 0.36). In the year 2021, a systematic literature review and meta-analysis evidence discovered that ankle dorsiflexion ROM significantly increased after flossband intervention compared to the baseline, and the effect size was 0.46 [8]. At the level of equivalent evidence, only one study examined application flossband for 4 weeks, and the small effect size evidence showed that ankle dorsiflexion ROM was significantly increased after 4 weeks of intervention [23]. In contrast to the above studies, Galis and Cooper [24], Kaneda [25], and Ross and Kandassamy [21] pointed out that flossband significantly increased ankle dorsiflexion ROM with medium effect size in healthy active young participants, and the effect size was 0.77, 0.61, 0.56, respectively. Vogrin [27] also showed that flossband intervention significantly increased ankle dorsiflexion ROM with medium to large effect size in healthy young participants. McCallum"s [29] study revealed that 3 weeks of applying flossband on patients with chronic ankle sprains also significantly improved ankle dorsiflexion ROM with medium effect size (d = 0.76). The varying results on different levels of improvement after flossband application were due to the amount of tension or wrapping pressure and wrappling methods in these studies. Around 50% tension of flossband or 150 mmHg wrapping pressure could improve ankle dorsiflexion ROM more than the other types of wrapping tension and pressure. In Galis and Cooper"s [24] study, the researcher found that applying 150 mmHg wrapping pressure on the ankle could significantly increase dorsiflexion ROM compare to 200 mmHg wrapping pressure and low wrapping pressure. Kaneda [25], Ross and Kandassamy [21], and McCallum [29] also pointed out that 160 ± 3 mmHg or 50% tension could improve ROM with medium effect size compared with the other studies which used high pressure or stretch tension. Meanwhile, the variance of flossband application on different parts of the human body could be another factor that led to the differing results. Therefore, 50% tension of flossband or 150 mmHg wrapping pressure could be a generalization for the other joints and more research about the long-term effects of flossband should be conducted in future studies.
Flossband application is not only beneficial to improve ankle ROM, but has also been proven to increase the ROM of other joints. Kiefer assessed the effect of flossband on the shoulder joint of healthy college students, and the results showed that the acute intervention significantly increased shoulder flexion ROM [20]. Hadamus [14] concluded that trunk flexibility was also significantly improved after using flossband as a warm-up assistant tool compared to the control group. Knee flexion ROM was significantly improved after flossband application, but this improvement only had a small effect size (d = 0.47) [5]. Maustk found that flossband can be used to increase hip flexion when compared with to sham group or control group [12], but Konrad [17] mentioned that flossband may not be used to increase hip flexion. Hodeaux [28] pointed out that there was no significance for elbow flexion ROM between the flossband group and control group, but there was an improvement trend with small effect size (d = 0.32). By reviewing the studies of Hodeaux [28] and Konrad [17], small sample size may be one of the factors which led to a significant effect. Therefore, future studies should aim to recruit a bigger sample size. In addition, it is worth noting that most studies were focused on applying flossband on the ankle joint, especially on healthy athletes or active young people rather than patients. Therefore, there was less evidence showing the effects of flossband on the patients as well as the effect of flossband application on other body parts or joints. Thus, more related evidences should be sought after in future studies.
Flossband seems to act as an effective pain management tool by producing shear force on myofascia, increasing joint space, and improving blood circulation. That said, there was only one article reporting the application of flossband on knee pain patients. After flossband application, perceived pain in the knee was significantly reduced, and this study showed a big effect size [7]. Interestingly, the available evidence of flossband on pain management was scarce. Thus, more studies about the effect of flossband application for pain management of different etiologies should be conducted in the future.
Flossband might be used into reducing muscle tightness, thus, flossband could be a potentially therapeutic tool for injury prevention and rehabilitation of the skeletal muscular fascial system disease. Applying flossband on the hamstring significantly changed its function, especially increasing hamstring flexibility. There were only two studies on muscle flexibility changes after applying flossband on soft tissues. All the participants were asked to do active knee flexion and knee extension exercises in 2 minutes by wrapping flossband on the hamstring, and the small to medium effect size evidence showed that straight leg raise test was improved after removing the flossband compared to the control group with moderate pressure of flossband application [27]. Kaneda [25] also supported that flossband wrapping around hamstring muscles from above the knee significantly enhanced straight leg raise performance compared to the group without flossband. The mechanism behind the muscle flexibility changes caused by flossband may be due to shear force during tissue flossing or the thermal effect during flossing. However, the exact physiological mechanism of flossband has not been examined. In the future, more studies about the effects of flossband on skeletal muscular fascial system and its physiological mechanism needs to be conducted. Flossband is beneficial to enhance muscle strength, but there was controversial evidence of increasing muscle activity. Galis and Cooper [24] highlighted that nearly 150 mmHg of flossband wrapping pressure was possibly beneficial to improve ankle dorsiflexion peak torque after applying flossband on the calf muscles (d = 0.27). However, over wrapping pressure was observed to impair ankle dorsiflexion peak torque ability (Galis & Cooper, 2020). It can be seen that appropriate wrapping pressure may be an important factor affecting strength. Research finding showed that flossband wrapping around calf muscles significantly improved isometric maximal voluntary contraction (MVC) of ankle plantar flexion force at the end of plantar flexion (d = 0.27) and enhanced rate of force development within 0-50ms (d = 0.38). Meanwhile, there was a trend to activate calf muscles (d = 0.47) [9]. In contrast, evidence from a tensiomyography perspective showed that ankle flossband application on gastrocnemius muscle contraction time was not obvious [27]. The other evidences showed that applying flossband around the thigh improved eccentric MVC of the knee extension force (d = 0.59), flexion force (d = 0.56) and knee extension passive torque at the end of knee extension (d = 0.73) [25]. Konrad mentioned that wrapping flossband around the thigh significantly improved MVC of knee extension compared to the control group (d = 0.77), but leg muscle activation was not found in this study [32]. Vogrin [16] and Vogrin [27] pointed out that wrapping flossband around the thigh provided small to medium benefits to improve isometric MVC of knee extension force compared to the control group, and it significantly increased isometric MVC of knee extension and rectus femoris muscle contraction time after flossing. The underlying physiological mechanisms of flossband on the aspect of force production and muscle activation have yet to be determined, but available evidences showed that there are several viewpoints of using flossband to improve force production mechanism as well as improve neuromuscular function. Flossband could facilitate fascial layers sliding or arrange the disordered fascial tissue. The smooth sliding between the layers of fluid fascia could mediate local muscle contraction or elongation as well as restoration of muscle length for optimum myosin head coupling mechanism [33]. The heat from intramuscular friction would be another important factor which could impact muscle contraction strength [9]. Soft tissue flossing with compression also is a critical factor which directed neuromuscular control of coordination and movement [33]. Some studies even suggested that tissue flossing might promote the release of growth hormones and norepinephrine level following the compression [32]. Flossband wrapping on the soft tissue indeed increased muscle strength and enhanced rate of force development, but it seemed to be not present in neuromuscular muscle activation. Therefore, essential evidence by using surface EMG evidence, ultrasound image evidence and physiological evidence on the level of neurological function after flossing needs to be investigated in the future.
Human functional movement quality can be improved through the tissue flossing technique. Flossband wrapping around ankle significantly improved squat performance when compared to pre-test performance, and it provided medium effect size benefits [11]. Small effect size evidence showed that wrapping flossband around the ankle could be beneficial for sprint performance and vertical jump ability compared to the control group [19]. Another evidence supported that there was small effect size enhancement in jump height and jump velocity between the flossband group and control group, and there was significant improvement in jump height after flossing [19]. Applying flossband on the knee pain patients also improved jump performance. This result was consistent with the previous findings, but the difference was that it 1172 The Effect of Tissue Flossing Technique on Sports and Injury Prevention and Rehabilitation: A Systematic Review of Recent Research also improved jump velocity, jump power, jump force and jump time in this study. Therefore, the use of flossband on patients led to obvious improvements in jumping performance [7]. Knorad [32] showed that flossband wrapping around the thigh could not increase the vertical jump height, and he also pointed out that flossband application on the thigh in healthy participants was not enough to induce significant changes in jump height because jumping is a complex function movement which is related to several muscle groups. Milles [13] found that applying flossband on the highly treated ruby athletes had less potential to improve jump performance and sprint performance. However, a meta-analyses evidence confirmed that there was a positive impact of flossing on jump performance [26]. Available evidence showed that the effects of flossband could lead to noticeable improvement in the general population or patients. Thus, more studies on different populations should be done in the future.

Conclusions
Flossband as a novel and emerging therapeutic tool has been used in sport as well as clinical practice in recent years. Based on the findings in previous studies, flossband wrapping on different soft tissues or peripheral joints could be a valid method to increase joint ROM, manage pain, and reduce muscle tightness. Not only that, it could also have other potential benefits and enhance muscle strength, exert higher rate of force development in per unit time, as well as improve physical functional performance such as squat, sprint and jump ability. In addition, the key to apply this technique is mastering the wrapping tension and pressure. Specifically, 50% flossing tension or approximately 150 mmHg wrapping pressure could lead to positive effects on the outcomes of ROM, pain, muscle stiffness, muscle strength and physical function performance when compared with low or high tension or pressure. Therefore, the above findings indicate that flossband is a useful treatment option, and it can provide significant contribution in the field of athletic training, sports injury prevention and rehabilitation in the future.

Perspective for Future Research
Based on the previous studies, limited evidences showed that flossband as a novel technique provided small to medium effect size benefits in the aspects of increasing ROM, strengthening muscle force, releasing muscle tension and improving physical functional performance. Additionally, it showed a high effect size for pain management. Unfortunately, these evidences of flossband mostly involved soft tissues and joints of the limbs, and none of studies examined the effects on trunk function or evaluated its specific physiological mechanism. Therefore, it would be pertinent for future studies to broaden the field of flossband application and further investigate its physiological mechanism. In addition, most studies were mainly conducted on a population of healthy and active participants or well-trained athletes, and very little research has been done with patients. At the same time, those studies only investigated the short-term effects rather than the long-term effects of flossband application on different soft tissues or peripheral joints. Therefore, more studies about the effects of flossband application with patients should be implemented in the future, especially with regards to the long-term effects of flossband application.