The Influence of Self-Myofascial Release on Muscle Flexibility in Long-Distance Runners

uring long-distance running, athletes are exposed to repetitive loads. Myofascial struc- tures are liable to long-term work, which may cause cumulating tension within them. The aim of this study was to evaluate the acute effect of self-myofascial release on muscle exibility in long-distance runners. The study comprised 62 long-distance, recreationally running participants between the age of 20 and 45 years. The runners were randomly divided into two groups: Group 1 (n= 32), in which subjects applied the self-myofascial release technique between baseline and the second measurement of muscle exibility, and Group 2 (n= 30), without any intervention. The self-myofascial release technique was performed according to standardized foam rolling. Assessment of muscle exibility was conducted according to Chaitow's proposal. After application of the self-myofascial release technique, higher values were noted for the measurements of the following muscles: piriformis, tensor fasciae latae muscles and adductor muscles. Within the iliopsoas and rectus femoris muscles, lower values were observed in the second measurement. These changes were statistically signi cant (p< 0.05) within the majority of muscles. All these outcomes indicate improvement related to larger muscle exibility and also, an increase in range of motion. In the control group (Group 2), signi cant improvement was observed only in measurements for the iliopsoas muscles. The single application of self-myofascial

were observed in the second measurement. These changes were statistically signi cant (p< 0.05) within the majority of muscles. All these outcomes indicate improvement related to larger muscle exibility and also, an increase in range of motion. In the control group (Group 2), signi cant improvement was observed only in measurements for the iliopsoas muscles. The single application of self-myofascial release techniques with foam rollers may signi cantly improve muscle exibility in long-distance runners. Based on these results, the authors recommend the self-myofascial release technique with foam rollers be incorporated in the daily training routine of long-distance runners, as well as athletes of other sport disciplines. Keywords:self-myofascial release; foam rolling; muscle exibility; foam roller 1. Introduction Running is a natural form of movement and one of the most popular types of activity. However, as in the case of other sport disciplines, running involves being subjected to risk of injuries and overloads. With the increase in popularity of this form of physical activity, the frequency of injuries associated with its practice also increases, especially within the lower limbs [1–3]. The highest activity of the lover limb muscles occurs immediately before initial contact and at the beginning of the support phase. The increased range of movement in the joint during running elongates the time of muscle activity. During long-distance running, athletes are exposed to repetitive loads. Myofascial structures are liable to long- term work, which may cause cumulating tension within them. This is especially true in the case of eccentric work of the hamstring during the terminal swing phase, which may lead to excessive tension and reduction of this exibility within this muscle group. Thus, maintaining proper muscle exibility is crucial for long-distance runners [4]. Flexibility may be de ned as the property and ability of body tissues to achieve full range of motion (ROM) without any injury to the joints or within their groups. Range of motion is regulated by proper extensibility of all soft tissues encompassing the joints[5,6]. The basic role of exibility is to reduce the risk of injury. Proper muscle elasticity increases Int. J. Environ. Res. Public Health2022,19,

property and ability of body tissues to achieve full range of motion (ROM) without any injury to the joints or within their groups. Range of motion is regulated by proper extensibility of all soft tissues encompassing the joints[5,6]. The basic role of exibility is to reduce the risk of injury. Proper muscle elasticity increases Int. J. Environ. Res. Public Health2022,19, 457.

Int. J. Environ. Res. Public Health2022,19, 457 2 of 11 the ability to move joints within their maximal possible range of motion. Moreover, ex- ibility exercises or techniques used before a main training event may enhance physical performance, especially that of muscle strength. This is achieved by increasing the use of elastic strain energy during the performance of movements [7]. One technique, the aim of which is to increase exibility of the soft tissues, is myofascial release (MFR). MFR is based on manual therapy and helps reduce restrictions or adhesions within layers of the fascial tissue [8]. Myofascial release includes different procedures, such as structural integration (Rol ng), osteopathic soft-tissue techniques, massage, trigger point release, the muscle energy technique and others [9]. Most of them are passive techniques in which the patient is dependent on a therapist [10]. A special technique within MFR is self-myofascial release (SMFR). In contrast to those techniques mentioned above, SMFR is performed by the patient independently, instead of by a therapist. This technique utilizes the patient's body mass and special tools such as massage balls or foam rollers to apply pressure and stretch the restricted soft tissue [10–12]. Foam rollers used in the SMFR technique are cylinders made of foam with various texture, size and density [10,13]. Foam rollers have their usage in treating large groups of muscles with a speci ed protocol of starting and ending position [14]. SMFR involves movements back and forth over the tool, from the proximal to distal part of the muscle groups, and inversely. In the case of the myofascial trigger points (MTrP), the SMFR technique is concentrated over the painful area to provide sustained compression on the MTrP [10,15]. The effectiveness of SMFR is explained by sweeping and direct pressure on soft tissue, which may cause warming of the fascia, ripping of brous adhesions and restrictions within layers of the fascia and restoring soft tissue elasticity [16]. Moreover, fascial elasticity is contingent upon tissue hydration. The more hydrated the tissues, the less rigid they are. Some parts, where the fascia is less elastic because of brous adhesions and

direct pressure on soft tissue, which may cause warming of the fascia, ripping of brous adhesions and restrictions within layers of the fascia and restoring soft tissue elasticity [16]. Moreover, fascial elasticity is contingent upon tissue hydration. The more hydrated the tissues, the less rigid they are. Some parts, where the fascia is less elastic because of brous adhesions and restrictions, are less hydrated. The SMFR technique allows to increase elasticity of the fascia and the degree of its hydration. During compression via foam rollers, the fascia has been shown to extrude water. After rolling, when pressure on the fascia decreases, there is a re-in ow of water from the surrounding tissues, as well as the lymphatic and vascular networks. Compression during the SMFR technique may increase fascial elasticity and compliance through a temporary change in water content [17,18]. Another explanation indicates ischemic compression during performance of the SMFR technique. The local blood ow is increased after achieving compression. As a result, removal of metabolites, delivering oxygen and tissue treatment are facilitated [19–21]. There are many studies in which the effectiveness of SMFR using foam rollers is shown. This technique is commonly recommended as a part of the warm-up phase due to its positive in uence on the length-to-tone ratio within the muscles [22]. It can be both a form of warm-up or cool-down of the body after physical activity [14]. It may also be used in the prevention of injuries. SMFR is a technique applied to restore proper tension of tissues, increasing their exibility [16,23–25], removing trigger points [8,26] and enhancing muscle recovery after exercise [14,27,28]. However, despite the many existing studies on this topic, none of them involves the in uence of SMFR on muscle exibility in runners. The exibility and proper function- ing of myofascial chains are crucial for athletes. Due to myofascial structure continuity, overloading forces may be transferred by the myofascial system, leading to tissue over- load, repetitive strain injuries, resulting restrictions in muscle exibility and disruptions in functional movement patterns. Moreover, restrictions in one part of the body may cause excessive tension in others

The exibility and proper function- ing of myofascial chains are crucial for athletes. Due to myofascial structure continuity, overloading forces may be transferred by the myofascial system, leading to tissue over- load, repetitive strain injuries, resulting restrictions in muscle exibility and disruptions in functional movement patterns. Moreover, restrictions in one part of the body may cause excessive tension in others [29]. There are some studies in which a concern is put forward, stating that chronic endurance training may induce decreased exibility [30,31]. An optimal level of this parameter is necessary for health. Higher muscle exibility can produce a protective role against muscle damage during exercise [32,33]. Long-distance running is one of the most popular sport disciplines wherein athletes are exposed to repetitive loads; thus, improving exibility should be crucial in this discipline. In the current study, this

Int. J. Environ. Res. Public Health2022,19, 457 3 of 11 issue is undertaken for the rst time. The aim of this study was to evaluate the acute effect of self-myofascial release on muscle exibility in long-distance runners. 2. Materials and Methods 2.1. Study Group The study comprised 62 long-distance, recreationally running participants (18 females and 44 males), aged 20–45 years (mean SD 33.79 7.56). The participants ran regularly at a total distance of 30–100 km per week (mean SD 48.15 km 17.02 km). The recruitment of runners was performed according to exclusion and inclusion criteria. The inclusion criteria were as follows: weekly covered distance of 30 km or more, regular running training, age between 20 and 45 years, no deformation of the feet, no acute injury lasting up to 6 months prior to enrolment in the study and consent for participation. The inclusion criteria were created on the basis of data from the International Institute for Race Medicine [34]. The exclusion criteria were as follows: weekly distance of less than 30 km, irregular running training, age above 45 or less than 20 years, visible deformation of the feet, previous history of acute injury lasting up to 6 months prior to enrolment in the study, chronic pain, systemic disease (e.g., hypertension, diabetes, bromyalgia) or lack of consent to participate in the study. The subjects were requested to refrain from physical activity 24 h prior to measurements and foam rolling 3 days before testing. Before the study, all of the participants were informed about the research procedures as well as the purpose of the study in detail and provided their written informed consent to participate in the research. This study was registered in the Australian New Zealand Clinical Trials Registry (ANZCTR) and the written approval of The Ethical Committee of Regional Medical Chamber was obtained (No. 40/KBL/OIL/2015). All the procedures complied with the 1964 Declaration of Helsinki. The runners were randomly divided into 2 groups: Group 1 (n= 32), in which subjects applied the self-myofascial release technique between baseline and the second measurement of muscle exibility, and Group 2 (n= 30), without

the written approval of The Ethical Committee of Regional Medical Chamber was obtained (No. 40/KBL/OIL/2015). All the procedures complied with the 1964 Declaration of Helsinki. The runners were randomly divided into 2 groups: Group 1 (n= 32), in which subjects applied the self-myofascial release technique between baseline and the second measurement of muscle exibility, and Group 2 (n= 30), without any intervention. The researchers used simple randomization by ipping a coin. The researcher was blinded to the subject group allocation. A detailed characterization of both groups is presented in Table. Table 1.Detailed characteristics of the groups. Group 1 (n= 32) Mean SD Group 2 (n= 30) Mean SD Age 34.09 7.73 33.46 7.33 Males 22 18 Females 10 12 High [cm] 175.81 8.73 177.60 7.63 Body mass [kg] 69.88 9.55 70.70 8.79 Total distance covered per week [km] 47.34 16.10 49.00 17.91 SD—standard deviation; cm—centimeters; kg—kilograms; km—kilometers. 2.2. Procedures Before the testing session, participants from Group 1 were familiarized with the proper performance of self-myofascial release using foam rollers. Three days after familiarization, the runners were invited for the proper testing session. The testing session began with a 5 min warm-up during which participants of both groups ran at a comfortable pace. Then, muscle exibility was assessed twice: at base- line and after 15 min. Following the rst examination, each participant from Group 1 applied the self-myofascial release technique using foam rollers on the following muscles: hamstring, gluteus maximus, hip adductors, quadriceps, tensor fasciae latae and gastroc- nemius. Runners from Group 2 did not perform any of the techniques between rst and second measurements.

Int. J. Environ. Res. Public Health2022,19, 457 4 of 11 In that study, a 45cm high and 14cm diameter, high-density 4Fizjo brand foam roller was used. SMFR using foam rollers was performed according to the standardized foam rolling procedure [35]. This technique was applied along the muscle bers, from proximal to distal muscle insertion, and inversely, with a constant pressure and speed of 2.5 cm/s. The correct speed of SMFR was demonstrated and then monitored by the researcher while the subject performed the technique. Participants repeated this technique 10 times for each muscle group. The SMFR was applied an average of 2 min for each muscle group. Foam rolling was performed on both lower limbs. The SMFR was applied only on the muscle tissue, avoiding pressure on bones, joints or tendons. 2.2.1. Rolling of the Hamstring The SMFR technique was performed in back support position with hands on the oor. The runner rolled 1 lower limb, starting above the popliteal fossa towards the ischial tuberosity, and inversely. The second leg was braced on the ground as support (Figure).Int. J. Environ. Res. Public Health 2022, 19, x FOR PEER REVIEW 4 of 12 The testing session began with a 5 min warm-up during which participants of both groups ran at a comfortable pace. Then, muscle flexibility was assessed twice: at baseline and after 15 min. Following the first examination, each participant from Group 1 applied the self-myofascial release technique using foam rollers on the following muscles: ham- string, gluteus maximus, hip adductors, quadriceps, tensor fasciae latae and gas- trocnemius. Runners from Group 2 did not perform any of the techniques between first and second measurements. In that study, a 45cm high and 14cm diameter, high-density 4Fizjo brand foam roller was used. SMFR using foam rollers was performed according to the standardized foam rolling procedure [35]. This technique was applied along the muscle fibers, from proximal to distal muscle insertion, and inversely, with a constant pressure and speed of 2.5 cm/s. The correct speed of SMFR was demonstrated and then monitored by the researcher while the subject performed the technique. Participants repeated

SMFR using foam rollers was performed according to the standardized foam rolling procedure [35]. This technique was applied along the muscle fibers, from proximal to distal muscle insertion, and inversely, with a constant pressure and speed of 2.5 cm/s. The correct speed of SMFR was demonstrated and then monitored by the researcher while the subject performed the technique. Participants repeated this technique 10 times for each muscle group. The SMFR was applied an average of 2 min for each muscle group. Foam rolling was performed on both lower limbs. The SMFR was applied only on the muscle tissue, avoiding pressure on bones, joints or tendons. 2.2.1. Rolling of the Hamstring The SMFR technique was performed in back support position with hands on the floor. The runner rolled 1 lower limb, starting above the popliteal fossa towards the is- chial tuberosity, and inversely. The second leg was braced on the ground as support (Figure 1). Figure 1. Rolling of the hamstring. 2.2.2. Rolling of the Gastrocnemius The SMFR technique was performed in back support position with hands on the floor. The study participant put the foam roller under the calf, with the knee joint in ex- tension. The foot of the second lower limb was supported on the ground. The subject moved back and forth over the foam roller starting over the Achilles tendon towards the knee joint, and inversely (Figure 2). Figure 1.Rolling of the hamstring. 2.2.2. Rolling of the Gastrocnemius The SMFR technique was performed in back support position with hands on the oor. The study participant put the foam roller under the calf, with the knee joint in extension. The foot of the second lower limb was supported on the ground. The subject moved back and forth over the foam roller starting over the Achilles tendon towards the knee joint, and inversely (Figure).Int. J. Environ. Res. Public Health 2022, 19, x FOR PEER REVIEW 5 of 12 Figure 2. Rolling of the gastrocnemius. 2.2.3. Rolling of the Gluteus Maximus The study participant sat on the foam roller, crossing 1 foot over the opposite knee. The hands were placed

the foam roller starting over the Achilles tendon towards the knee joint, and inversely (Figure).Int. J. Environ. Res. Public Health 2022, 19, x FOR PEER REVIEW 5 of 12 Figure 2. Rolling of the gastrocnemius. 2.2.3. Rolling of the Gluteus Maximus The study participant sat on the foam roller, crossing 1 foot over the opposite knee. The hands were placed on the floor behind the back. The runner moved back and forth over the foam roller to roll the gluteus muscle (Figure 3). Figure 3. Rolling of the gluteus maximus. 2.2.4. Rolling of the Hip Adductors The SMFR technique was applied in front support position on the forearms. One lower limb was placed on the foam roller in flexion, with external rotation and abduction in the hip joint. The subject moved back and forth over the foam roller, starting over the knee joint towards the groin, and inversely (Figure 4). Figure 4. Rolling of the hip adductors. Figure 2.Rolling of the gastrocnemius. 2.2.3. Rolling of the Gluteus Maximus The study participant sat on the foam roller, crossing 1 foot over the opposite knee. The hands were placed on the oor behind the back. The runner moved back and forth over the foam roller to roll the gluteus muscle (Figure).

Int. J. Environ. Res. Public Health2022,19, 457 5 of 11Int. J. Environ. Res. Public Health 2022, 19, x FOR PEER REVIEW 5 of 12 Figure 2. Rolling of the gastrocnemius. 2.2.3. Rolling of the Gluteus Maximus The study participant sat on the foam roller, crossing 1 foot over the opposite knee. The hands were placed on the floor behind the back. The runner moved back and forth over the foam roller to roll the gluteus muscle (Figure 3). Figure 3. Rolling of the gluteus maximus. 2.2.4. Rolling of the Hip Adductors The SMFR technique was applied in front support position on the forearms. One lower limb was placed on the foam roller in flexion, with external rotation and abduction in the hip joint. The subject moved back and forth over the foam roller, starting over the knee joint towards the groin, and inversely (Figure 4). Figure 4. Rolling of the hip adductors. Figure 3.Rolling of the gluteus maximus. 2.2.4. Rolling of the Hip Adductors The SMFR technique was applied in front support position on the forearms. One lower limb was placed on the foam roller in exion, with external rotation and abduction in the hip joint. The subject moved back and forth over the foam roller, starting over the knee joint towards the groin, and inversely (Figure).Int. J. Environ. Res. Public Health 2022, 19, x FOR PEER REVIEW 5 of 12 Figure 2. Rolling of the gastrocnemius. 2.2.3. Rolling of the Gluteus Maximus The study participant sat on the foam roller, crossing 1 foot over the opposite knee. The hands were placed on the floor behind the back. The runner moved back and forth over the foam roller to roll the gluteus muscle (Figure 3). Figure 3. Rolling of the gluteus maximus. 2.2.4. Rolling of the Hip Adductors The SMFR technique was applied in front support position on the forearms. One lower limb was placed on the foam roller in flexion, with external rotation and abduction in the hip joint. The subject moved back and forth over the foam roller, starting over the knee joint towards the groin, and inversely

This research investigates the impact of self-myofascial release on flexibility in long-distance runners.