Body Balance after Fascial Therapy in Athletes with Soft Lower Limb Muscle Injuries

Background: Most injuries in competitive sports are due to overstrain and excessive muscular and fascial tension. This study aimed to assess the effects of a single session of fascial therapy on balance and lower limb weight-bearing in professional athletes following a lower limb soft-tissue injury. Methods: A pedobarographic platform was used to assess the weight-bearing on both lower limbs and corporal balance. A total of 41 athletes with an acute soft-tissue injury involving the quadriceps femoris muscle were included in the study. Each patient underwent myofascial therapy in the injured limb only. The therapy was intended to release tension and improve proprioception. Results: The injured and healthy limbs showed significant asymmetry in body weight distribution. Before treatment, the patients bore less weight on the injured limb than on the healthy limb. After fascial therapy, eyes-closed tests showed an improved weight distribution symmetry between the two lower limbs. There were no significant differences in the values of the evaluated balance parameters between those measured at baseline and those measured after the therapy, measured after the rehabilitation session. Conclusions: A single fascial therapy session has a beneficial effect on corporal balance in runners with an injured lower limb.


Introduction
Professional sports, including athletics, may lead to injuries during training sessions and competitions. Physical training requires repetitively executing a particular act, which may lead to overstraining. The risk of overstraining increases in top-tier athletes since competing at the highest levels does not only require a rigorous training schedule but is also associated with pressure from the trainer, and the drive to achieve very high performance.
Myofascial injuries continue to be very common among athletes [1]. Injuries in athletes are most commonly associated with cumulative microtrauma, which leads to musculoskeletal strain. The disorders most commonly reported in the literature are the iliotibial band syndrome, patellofemoral pain syndrome, 'shin splints', Achilles tendonitis, and plantar fasciitis [1,2]. According to some authors, one important factor in developing pain due to overstraining is the formation of the so-called 'trigger points', which may cause a pain that progressively intensifies with muscle tension and radiates to other regions of the body, irritating the fascia and subcutaneous tissue [3]. The term 'myofascial pain syndrome' is, in fact, inextricably associated, and sometimes used interchangeably, with the term 'myofascial trigger points'. However, it is not entirely clear if the presence of myofascial trigger points should define myofascial syndrome [4].
Most injuries in athletes are due to overstrain and excessive myofascial tension, hence the importance of fasciae in treatment and prevention efforts in this group.
A fascia, composed of a variety of intertwined collagen fibers of varied thickness, is a type of internal connective tissue divided into three layers: superficial layer, potential space layer, and deep layer [5][6][7]. Because fibers of the fascia run in many directions, it can change with the surrounding tissues. The fascia is considered to be one continuous piece of tissue that functions in linked "chains" to create a tonus in the body [8].
The function of individual fascial components ensures the body's integrity. This may involve controlling the orientation of muscle fibers by reflecting the force vector and facilitating a smooth resolution of muscle tension [9,10]. Apart from their protective function and ensuring adequate gliding of adjacent structures, fasciae play a role in neurosensory mechanisms and are closely associated with the autonomic nervous system, all of which help maintain balance [6,11,12]. The structure and histological anatomy of myofascial tissue shows "tensegritive" properties. They enable the transfer of gravity, creating a structure capable of supporting body weight and significantly reducing the neuromuscular effort required to maintain the center of mass [13,14]. When controlling posture, the fascia acts as a kind of spring without hysteresis and plays a crucial role in maintaining balance and supporting an upright posture [13,14]. The role of fascia (which is made up of connective tissue) is not only to transfer the strain generated by training but also to accumulate energy. This is achieved by fascial elasticity [12].
The role of fasciae in maintaining balance is associated with the phenomenon of proprioception. Fascial tissue is rich in proprioceptors, which allow it to detect stimuli from the external environment and control motor responses by initiating the movement or tensing of tissues. This helps in being aware of the position of individual parts of the body in space even without visual control [15]. Fasciae control entire muscle chains, e.g., the bi-layered fascia of the large muscles of the torso is continuous with the deep fasciae of the lower limbs; also, the connective tissue of the latissimus dorsi muscle is continuous with that of the gluteus maximus muscle [16].
Fascial therapy plays an important role in ensuring the normal functioning of the body. Currently, many publications have emphasized the more active role of connections due to the innate ability to contract actively. From their clinical experiences, manual therapists also have observed changes in the tension of the fascia in response to its manipulation [17,18].
Static and dynamic strains, inappropriately selected physical activity, long-term stress, injuries, or immobilization may alter the connective tissue structure. Piezoelectric discharges generated by long-lasting shortening or excessive stretching of a muscle stimulate fibroblasts to overproduction of collagen, which leads to muscular band thickening, reduced elasticity, and dysfunction. These, in turn, lead to diminished muscle strength, connective tissue adhesiveness (densification), and increased muscle soreness [3,19,20].
The purpose of this study was to assess the effect of a single fascial therapy session on the balance and body weight distribution between the lower limbs in professional athletes following lower limb soft-tissue injury.

Materials and Methods
The study assessments were conducted at a laboratory of Physiotherapy for Musculoskeletal Functional Disorders, University School of Physical Education in Wrocław, in the years 2018 and 2019. The study group comprised 41 athletes, specifically runners, of both sexes (26 men and 15 women) from the Poland National Team, with a history of an incident involving lower limb soft tissues, particularly the quadriceps femoris muscle. The study groups had an acute lower limb soft-tissue injury and a training experience (in running) of at least 2 years. The study inclusion criteria were history of a lower limb muscle injury 7-8 weeks prior to the study, no lower limb surgery for at least 9 months previously, a minimum of 12 weeks after the completion of treatment for any other lower limb injuries, no lower limb length discrepancy, and no neurological, cardiological, or psychiatric disorders. Study recruitment was conducted based on a custom questionnaire involving basic personal information, anthropometric parameters, training experience, and current or past history of musculoskeletal injuries. The athletes' height was measured to the nearest centimeter crown to heel without shoes using a stadiometer, and weight was measured in light clothes to the nearest 0.1 kg using a portable scale. The body mass index (BMI) was calculated from the equation: body mass (kg)/height squared (m 2 ) (WHO 2000).
The study was approved by the local Bioethics Committee (No 585/2011). All patients were informed that their participation in the study was voluntary. Furthermore, all subjects were informed about the aim and methods of the study and gave their written informed consent before taking part in the study.
Our study was conducted in three stages: baseline assessments, 60 min of a fascial therapy session in the same procedure for the injured lower limb, and a final assessment evaluating the effects of the intervention directly after a massage. The baseline and final assessments were conducted the same way.
The weight born on each lower limb and the corporal balance of athletes were assessed with a Zebris Medical GmbH pedobarographic platform ( Figure 1). The pedobarographic platform has an area of 320 × 470 mm and includes 1504 sensors, allowing for both static and dynamic tests to be carried out. This device is used to assess the equilibrium and balance of the body in both athletes and patients with various problems with the locomotor system undergoing various forms of treatment. The accuracy and reliability of the device have been confirmed by other researchers [21][22][23][24]. The platform, equipped with calibrated resistive barometric pressure sensors, provided measurements of force distribution under dynamic and static conditions. Footprint software was used to gather the data on the distribution of pressure applied by the left and right lower limb during a static test and the position of the center of pressure (CoP) during the corporal balance test. All measurements were taken once the patients had completed a custom questionnaire to qualify them for study entry and familiarize them with the character and conditions of the study.
Plantar pressure distribution for the two limbs and the balance test were performed during a 60-s static test with the eyes open and 60-s static test with the eyes closed. The static test provided data on the differences in the amount of load being placed on the injured and uninjured limb, whereas the balance tests, conducted with the eyes open and closed both prior to and after therapy, assessed the CoP-related parameters. During all tests, the patient was standing barefoot on a pressure distribution measurement (PDM) platform, with the feet placed symmetrically and equidistant from the center of the platform. Three measurements were made each time, one after the other, and the test results were averaged. Eyes-open tests were performed first and followed by the eyes-closed tests.
The following CoP-related parameters were considered in the balance assessments: mean center of CoP x (MCoCx), i.e., the mean path of CoP (in centimeters) along the platform's x-axis; mean center of CoP y (MCoCy), i.e., the mean path of CoP (in centimeters) along the platform's y-axis; CoP sway path length (SPL) (in centimeters) during 60 s; width of ellipse (WoE), indicating the amplitude; height of ellipse (HoE); and area of an ellipse (AoE).
After the baseline assessments involving a static test and balance control test with the eyes open and closed, an approximately 60-min fascial therapy session was conducted. The therapy was directed at the affected limb exclusively and was intended to release tension and improve proprioception. Each of the myofascial techniques lasted from 2 to 4 min, depending on the level of soft tissue tension. The therapeutic procedure was conducted according to the following protocol: (1) a myofascial technique to relax the quadratus lumborum muscle; (2) a global technique for the erector spinae muscle; (3) a myofascial technique for the piriformis muscle; (4) a myofascial technique targeting fascial restriction; (5) transverse kneading of the medial femoral intermuscular septum; (6) longitudinal kneading of the medial femoral intermuscular septum; (7) fascial manipulation applied to the area proximal to the knee joint (in the distal thigh); (8) a technique releasing the distal part of the fascia located proximal to the patella, with the quadriceps femoris muscle tensed; (9) performing the technique on the soleus muscle; (10) soft-tissue mobilization in the distal part of the knee joint via fascial manipulation distal to the knee joint; (11) a myofascial technique targeting fascial restriction; (12) fascial manipulation applied to the medial crural intermuscular septum; (13) fascial manipulation applied to the supramalleolar region; (14) fascial manipulation in the metatarsus; (15) manipulation of the ischiocrural muscle fasciae (targeting fascial restriction); (16) manipulation of the crural muscle fasciae (targeting fascial restriction); and (17) manipulation of the Achilles tendon ( Figure 2). After myofascial therapy completion, the final assessments were conducted according to the same protocol as the baseline assessments.
The data were analyzed using the SigmaPlot (Systat Software Inc., London, UK) statistics package, version 13. Continuous variables were first analyzed for normal distribution using the Kolmogorov-Smirnoff test with the Lilliefors correction. All of the values are expressed as the mean ± standard deviation (SD) or the 25th-75th percentiles and 5th-95th percentiles (Figures 3 and 4). An unpaired Student's t-test was used to test the differences between the independent values. For data that did not pass the normality test, the significance of the differences was analyzed by the Mann-Whitney U test. The differences between the dependent data were analyzed by the Student's paired t-test or by the Wilcoxon Signed Rank Test (for data which were not normally distributed). A p-value < 0.05 was considered statistically significant.

Selected Demographic and Anthropometric Parameters
The persons included in the study were athletes who professionally trained short-and medium-distance runs for 2-6 years, aged from 18 to 25 years. All lived in Poland. The most common injury concerned the right limb (78%), regardless of gender.
One important factor affecting the amount of weight born by the lower limbs was body weight. For the men in the study group the mean body weight and height were 78.6 ± 10.4 (kg) and 180 ± 6 (cm), respectively, whereas for women these parameters were 59.5 ± 8.9 (kg) and 167 ± 7 (cm). The BMI was 24.3 ± 2.1 (kg/m 2 ) for men and 21.6 ± 2.7 (kg/m 2 ) for women. The BMI of 88% the men and all women were within the WHO healthy weight range and overweight BMI > 25 kg/m 2 in 12% of men (WHO 2000). We did not observe obesity.

Assessment of Body Weight Distribution between the Lower Limbs during an Eyes-Open and Eyes-Closed Test
We assessed the distribution of pressure between the two lower limbs (Table 1 and Figure 3) and the patient's balance during 60-s static tests with the eyes closed and open. Baseline measurements of body weight distribution (expressed as percentages) during the eyes-open and eyes-closed tests showed significant differences in the load being placed on the healthy and injured limb (p < 0.001). During both the eyes-open and eyes-closed tests, the healthy limb bore considerably more weight than the injured limb. This may indicate that visual control has a negligible effect on maintaining balance during the tests. After the fascial techniques were applied, the results improved considerably in the eyesopen test ( Figure 3A); however, there was still a statistically significant difference between the limbs (p = 0.034). The eyes-closed test ( Figure 3B) showed no significant differences, which indicates that plantar pressure values from both feet became equal, i.e., there was a comparable load being placed on either foot. After the therapy, the difference between the injured and healthy limb loading decreased to 0.2 ± 2.5% (Figure 3).
The differences between body weight distribution asymmetry measured at baseline, and after 60 min of the fascial massage for injured legs vs. healthy legs, are shown in Figure 4.
∆BWDA (%) showed the differences in body weight between HL vs. IL for eyes open and closed at baseline and after a 60-min fascial therapy. Still, we did not observe statistically significant differences in ∆BWDA at baseline (10.3 ± 7.6 vs. 8.7 ± 6.9) nor after a massage (1.3 ± 4.8 vs. 0.3 ± 5.0) (p = 0.350 at baseline and 0.409 after massage). This shows that the difference in the distribution of balance when comparing the eyes open and closed position before and after the massage is not statistically significant in the study group, despite a statistically significant improvement after a 60-min massage. However, this observation concerns a specific group in terms of the health condition of young people and requires further research.

Assessment of Balance Parameters during Tests with the Eyes Open and Closed
The following CoP-related parameters were evaluated in the balance test: MCoCx, MCoCy, SPL during 60 s, WoE, HoE, and AoE ( Table 2). Analysis of MCoCy revealed no significant differences between its baseline and post-therapy values, either in the eyesclosed or eyes-open test. The baseline MCoCx values also showed no significant differences in the two tests. The improvement achieved with fascial therapy was not substantial enough to be considered significant. The same is true for WoE, whose values already showed no significant differences at baseline. We observed significant differences in balance between the eyes open and closed position only before a fascial massage for SPL, HoE, and AoE, with a p-value of 0.034, 0.033, and 0.014, respectively, but not for MCoCx, MCoC, and WoE.
The assessments conducted after the myofascial therapy session did not show significant differences in any of the parameters listed above, thus suggesting an improved balance control with the eyes closed following therapy, which indicates therapy effectiveness. The use of fascial techniques helped release fascial tension, which indirectly released muscle tension, which facilitated the perception of stimuli by the receptors located in these structures. Moreover, the therapy session reduced pain in the injured limb, as evidenced by the equalized body weight distribution between the two limbs. The achieved improvements in pain and proprioception considerably helped in maintaining balance while standing and reduced postural sway, as evidenced by the post-therapy SPL values.

Discussion
Fascia therapy has recently become a popular method in the treatment of orthopedic diseases. The study results are interesting; however, in the current and available literature, we did not find longitudinal studies and information on the use of the proposed therapeutic techniques in patients with the same dysfunctions within the human musculoskeletal system, as postulated by other authors [8]. It is also worth noting that our research should be treated as a preliminary report because it concerned a specific group of young, physically active people practicing the sport on a professional level.
This study measured selected parameters of corporal balance and weight distribution between the lower limbs with the use of a pedobarographic platform. The measurements were conducted under static tests with the eyes open and closed. The baseline assessments showed weight distribution asymmetry, with considerably less load being placed on the injured limb. This may be a result of trying to avoid pain and having better balance control in the healthy limb, which indirectly may be a result of proprioception worsened by excessive soft tissue tension in the injured area. Reducing the load placed on the injured limb and assuming a less painful position are very common phenomena, which is confirmed by studies of other authors. Giemza et al., who analyzed balance parameters, demonstrated a disturbed ability to maintain balance that improved after treatment [25]. We achieved a similar effect in our study. After a 60-min fascial therapy, the plantar pressures from both limbs equalized, which was noticeable in the eyes-closed test (without visual control). The primary reasons behind improved balance control are improved proprioception and pain reduction. Other authors also reported such differences in the eyes-closed test. Assessments involving a shift from a two-legged stance to a one-legged stance showed considerably increased CoP sway during the test performed with the eyes closed in patients with an injury [26].
We showed significant differences in the following CoP parameters: SPL, HoE, and AoE before therapy. Changes in these values might be due to the nature of the injured limb dysfunction. In our study group, recent surgical procedures were an exclusion criterion, and the injuries were due to overstrain; hence, the observed balance problems were not as pronounced as in patients following anterior cruciate ligament (ACL) reconstruction. Another study compared patients three years following ACL reconstruction and healthy volunteers. CoP SPL was greater in the ACL reconstruction group, with a particularly pronounced posterior sway [27]. Similarly, a study compared the balance in patients two years after lower limb surgery with that in the controls and demonstrated more pronounced abnormalities in the balance parameters in the surgery group [28]. A study that assessed the ability to maintain static balance after ACL reconstruction surgery showed similarly significant differences in the amount of load placed on the injured and healthy limbs through favoring the injured limb [29]. In another study, the authors compared three groups of subjects: healthy individuals with no musculoskeletal symptoms (HEA), individuals with unilateral symptomatic hip osteoarthritis (COX), and individuals with unilateral symptomatic hip osteoarthritis who had undergone hip replacement surgery (SURG). All subjects exhibited substantial differences for a number of variables between the measurements taken during a normal and narrow stance (base of support). The CoP path length and mean CoP velocity were considerably higher in the SURG group than in the COX group, with the HEA group showing the best ability to maintain balance in all tests [30]. The reports cited above confirm that injuries result in balance problems, and the patients have a tendency to put a lesser load on the injured limb. The effects of myofascial therapy on various dysfunctions have been described widely in the literature [31][32][33][34].
Beier et al. assessed the effect of myofascial therapy on the range of motion at the knee joint and peak and average muscle activity in the lower limbs (with the use of electromyography) [31]. While interpreting the results, those authors emphasized that analysis of the data collected from professional athletes may make it difficult to identify statistically significant differences in the evaluated parameters because of muscle memory induced by professional training. The authors stressed that this fact may be responsible for relatively good results obtained in professional athletes despite injury [31].
The body develops compensation strategies in order to avoid postural imbalance, falls, and subsequent injuries. When the base support is altered, the antagonistic muscles around the ankle joint co-contract. This is often associated with stiffness of adjacent tissues, including the tissues of the ankle joint itself. These muscular contractions help maintain balance and a steady posture while standing despite proprioceptive dysfunction. These abnormalities may be corrected through fascial therapy [32].
David et al. addressed the effect of myofascial release on improving proprioception, which may correlate with the frequency of injuries [33]. Earlier studies suggested that interventions such as soft-tissue therapies may be used in order to improve motor function. The authors emphasized that improving proprioception is necessary to restore motor control following an injury [33].
Cornel and Ebersole evaluated the effects of self-myofascial release achieved with a foam roller on the force of knee extension and on electromechanical activation of the quadriceps muscle [34]. Those authors observed no undesirable decreases in muscle activity. According to Cornel and Ebersole, self-myofascial release is a form of treatment that should be recommended to athletes, since-which is also confirmed by other reportsit has no negative effects on their performance and increases soft-tissue elasticity. Those authors suggested that potential physiological changes, e.g., increased arterial inflow, may render the fascia more pliable and increase muscle capacity to stretch, without affecting the electrical or mechanical aspects of muscle activation [34].
Physiotherapy techniques have a negligible effect on irreversible skeletal pathologies. However, working on the muscles, tendons, and fascia may produce positive results, including improvements in maintaining corporal balance. Fascial therapy is attracting more and more interest, with many authors emphasizing its analgesic and tension-releasing effects on soft tissues. Well performed therapy may contribute towards improving mobility in individual segments of the body, reduce the sensation of stiffness, and improve cardiovascular and nervous system function [5,12]. One characteristic feature of using myofascial release as part of manual therapy is the lack of a single universal approach. Thus, a protocol involving 17 fascial techniques was designed for the purpose of this study. These techniques aimed to provide fascial tension release via indirectly reducing muscle tension and to improve stimulus reception by the receptors located in these structures. The techniques used in our study reduced pain in the injured limb, which equalized the amount of load placed on either limb. Pain reduction and improvement in proprioception considerably improved the ability to maintain balance and produced less pronounced postural sway, as evidenced by post-therapy SPL values. The fascial techniques were applied to the region from the lumbar segment of the spine to the plantar aponeurosis on the injured side of the body. The phenomenon of tensional integrity, or 'tensegrity', helped us achieve improvement in every patient, irrespective of the exact location of their injury. We would like to emphasize that the site of pain reported by patients is often not the primary source of pain, and focusing the therapy only on this site may exacerbate symptoms [35].
There have been studies evaluating the effect of fascial therapy on the elasticity of selected muscle chains. These studies assessed the range of motion, measured during bending over and during sitting with the legs extended, and compared it with that after a single fascial therapy session involving the posterior muscle chain. The achieved reduction in tension-related pain suggests that a single therapy session may show differences in the tissue capacity to stretch [35]. The effect of pain on balance problems were confirmed by other studies conducted in individuals with painful lower limb osteoarthritis. Those studies showed improved balance (decreased CoP path length) in individuals experiencing less pain [36].
Soft-tissue mobilization is considered effective in improving the elasticity of the quadriceps muscle and hip flexors in professional runners. However, the issue of therapy effect duration remains under discussion [37]. Flackenstein et al. evaluated the potential role of myofascial release in regeneration and prevention of impaired muscle function [29]. That study indicated that regenerative foam rolling following physical exercise was sufficient to prevent further fatigue-related muscle impairments [38].
In sum, a physiotherapeutic session of manual therapy may not only reduce pain but also improve corporal balance and other balance parameters. According to some authors, all injuries have long-term effects, which are always apparent at the fascial level, and fascial abnormalities may reduce the body's capacity to control its posture [39].
Fascia-related issues have been receiving increasingly more attention from physicians and physiotherapists. Schleip points out the ongoing research on tools that may be used to augment objective analyses. For instance, an Ulm University team developed a tool for measuring the properties of fascial tissue located up to 2 cm deep. The tool helps assess tissue stiffness with a variable indentation depth, quantify the elastic storage capacity of tissues, and determine the pressure point threshold [40,41]. Schleip reported that the feeling of stiffness and myofascial disturbance that some patients present with may be due to a multisensory defense mechanism. This suggests that musculoskeletal impairments that are myofascial in nature may be a result of altered cerebral cortex function, and not only due to focal tissue abnormalities [40,41].
Further studies should include more thorough diagnostic assessments based on the use of an algometer, which is a device to measure pressure sensitivity (the least force, measured in kg/m 2 , required to produce pain) and surface electromyography.
The effects of treatment for myofascial pain (such as trigger point blocks, myofascial release, or manual therapy) intended to address soft-tissue dysfunction may be enhanced by the addition of physical rehabilitation. Moreover, patient education helps eliminate wrong movement patterns [3]. Well-designed cross-training, muscle balance, and general harmonious development of the body are of high importance for injury-free athletic achievements [16].

Summary
A single 60-min fascial therapy session has a beneficial effect on corporal balance in professional athletes with an injured lower limb. In our preliminary study, we found that: 1.
Significant differences between the amount of load placed on the injured and healthy limb in professional athletes, who had put less weight on the injured limb than on the healthy limb before the therapy for the injured limb was introduced.

2.
After the fascial therapy session, the weight distribution between the two lower limbs was shown to be more symmetrical in the test with the eyes closed; however, there was still a statistically significant difference in weight distribution in the eyes-open test.

3.
Prior to therapy, the values of the balance parameters (SPL, HoE, and AoE) obtained in the eyes-open and eyes-closed tests differed significantly.

Limitations
Our study has several limitations. The first limitation was the small sample size; however, the participants were of similar age, BMI, training internship, and sports discipline. Furthermore, we assessed professional, currently training athletes. Moreover, we did not consider information on pain, which is an important factor for body balance. We carried out a single 60-min massage as a kind of preliminary research on one hand, but on the other hand, we note that such an intervention is of great importance in the case of competitive sports, where the immediate therapeutic method determines the possibility of further participation, e.g., in competitions. Our research requires continuation on a larger group of athletes, with more interventions and with consideration of the level of pain. We also recognize that in continuation of the study, participants should be randomized, the design should be double-blind, and the clinician performing myofascial release should use it regularly in clinical practice. In the future, we also plan to include a control group of people who do not have any musculoskeletal dysfunction. The results of our study suggest that a relationship between balance and fascial massage in athletes exists, and this may become a stepping stone for further studies in this field.

Conclusions
A single 60-min fascial therapy session has a beneficial effect on corporal balance in professional athletes with an injured lower limb. Informed Consent Statement: Written informed consent was obtained from all subjects involved in the study.