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Overuse Injury: The Result of Pathologically Altered Myofascial Force Transmission?
Abstract
Overuse injuries are suggested to result from repetitive micro-damage eliciting pain in the
affected tissue. Therapy commonly focuses on the area of symptom localization, however, such approach may oversimplify the true etiopathology. This review hypothesizes that the development of some sports-related soft tissue disorders, e.g. plantar fasciitis or lumbago, is promoted by pathologically altered force transmission from anatomically connected structures.
... [31][32][33][34][35][36][37] Therefore, myofascial force transmission may affect pain, joint position perception, proprioception, joint ROM, and other disorders in musculoskeletal disease. 30,38,39 Patients with knee OA are likely to have a disturbance of passive myofascial tension in their lower limbs, which affects force transmission. For instance, quadriceps muscle atrophy and weakness are common in knee OA, 40 which may cause a reduction in force transmission. ...
... An abnormality of tension (eg, increased soft tissue stiffness or muscle weakness) of the structure at any link of the myofascial chain can lead to a disturbance (excessive or reduced) of the transmission of force, characterized by a high or low rate of change of torques at the joint. 39 This myofascial force transmission disorder may be responsible for some musculoskeletal diseases, 30,38,39 such as knee OA. Low-intensity resistance training with slow movement can be performed safely by elderly patients, potentially increase muscle mass, strength, and improve motor function. ...
... An abnormality of tension (eg, increased soft tissue stiffness or muscle weakness) of the structure at any link of the myofascial chain can lead to a disturbance (excessive or reduced) of the transmission of force, characterized by a high or low rate of change of torques at the joint. 39 This myofascial force transmission disorder may be responsible for some musculoskeletal diseases, 30,38,39 such as knee OA. Low-intensity resistance training with slow movement can be performed safely by elderly patients, potentially increase muscle mass, strength, and improve motor function. ...
Background:
Low-intensity resistance exercise therapy (LIRET) based on myofascial chains, applied to both affected and nonlocal joints, is an effective method for knee osteoarthritis (OA) rehabilitation. This study applied LIRET in a comparison of prevalues and postvalues of lower-limb tension in female patients with knee OA and asymptomatic participants.
Methods:
Twenty-four female participants with knee OA and 20 asymptomatic women took part in a 3-month long application of LIRET. Participants' ankle passive torque and ankle range of motion in the sagittal plane were assessed with an isokinetic dynamometer. The collected values were used to estimate the sagittal-plane lower-limb tension.
Results:
Compared with the asymptomatic group, participants with knee OA presented decreased maximum ankle dorsiflexion (P < .001), decreased ankle plantar flexion range (P = .023), ankle resting position more inclined to dorsiflexion (P = .017), increased ankle dorsiflexion stiffness (P = .005), and lower ankle plantar flexion stiffness (P = .034). After exercise intervention, the knee OA group self-reported less knee pain (P < .001), improved physical function (P < .001), increased maximum dorsiflexion (P = .021), and increased plantar flexion range (P < .001). While plantar flexion stiffness increased (P = .037), dorsiflexion stiffness decreased (P = .015) and ankle resting position moved toward dorsiflexion (P = .002). Results suggest possible decreased anterior leg tension and possible increased posterior leg tension in patients with knee OA.
Conclusions:
The results supported that knee OA patients present imbalanced myofascial tension of lower limbs. LIRET based on myofascial chains appears to decrease pain, and stiffness, and improve physical function of patients with knee OA and change their lower-limb tension.
... The properties of FR can influence damaged connective tissue rather than muscle tissue. This may explain the reduction in perceived pain without apparent loss of muscle performance [41]. Another postulated cause of improved recovery is that self-myofascial release increases blood flow, thus improving blood lactate clearance, reduction of edema, and oxygen supply to the muscle [41]. ...
... This may explain the reduction in perceived pain without apparent loss of muscle performance [41]. Another postulated cause of improved recovery is that self-myofascial release increases blood flow, thus improving blood lactate clearance, reduction of edema, and oxygen supply to the muscle [41]. Myofascial force transmission may play a role in the development and continuation of overuse injuries. ...
... Myofascial force transmission may play a role in the development and continuation of overuse injuries. Persistent increases in local stiffness can affect neighboring and adjacent tissues through the collagen connective tissue [41]. ...
The aim of this study was to compare the effects of various recovery techniques on muscle tissue after eccentric exercise-induced muscle fatigue (EIMF). Forty subjects (24.3 ± 2.6 years; 77.45 ± 8.3 kg; 177.0 ± 6.4 cm; 24.66 ± 1.6 kg∙m−2) were randomly assigned to one of the following groups: manual therapy (n =10, MT), mechanical vibration (n = 10, MV), percussion therapy (n = 10, PT) or foam roller (n = 10, FR). The contraction time (Tc) and the radial displacement (Dm) of the gastrocnemius was evaluated through tensiomyography (TMG). The application of the different techniques had positive effects for Tc and Dm in the treated leg compared to the untreated leg (F = 50.01, p < 0.01, η2p = 0.58 and F = 27.58, p < 0.01, η2p = 0.43, respectively) and for the interaction of the factors (Time x Leg x Therapy: F = 5.76, p < 0.01, η2p = 0.32 and F = 5.93, p < 0.01, η2p = 0.33, respectively). The results of the various methods used were similar: Tc (F = 0.17, p = 0.917; η2p = 0.01) and Dm (F = 3.30, p = 0.031, η2p = 0.22). PT interventions show potential for restoring muscle compliance and reducing stiffness, similar to MT and possibly more effective (cost-time relationship) compared to MV or FR.
... As a consequence of intermuscular continuity (Yucesoy, 2010;Wilke et al., 2016a;Wilke and Krause, 2019) it has been hypothesized that the modification of local tissue properties can affect adjacent structures (Wilke et al., 2019a): if the linkages connecting two muscles are stiff enough, they may transmit force. In fact, experimental trials made such observation, showing that length changes of lower leg muscles induced mechanical strains in neighboring synergists and antagonists (Huijing and Baan, 2001;Huijing et al., 2011). ...
... Our trial shows that maximal ankle dorsal extension is associated with significant caudal displacements of the semimembranosus muscle and its encapsulating fascia. This finding may explain the remote exercise effects detected in previous studies: It had been shown that stretching or self-myofascial release treatments induced flexibility increases in neighboring or even more distant cranial joints (Grieve et al., 2015;Wilke et al., 2016bWilke et al., , 2017Wilke et al., , 2019aJoshi et al., 2018). Although representing an intriguing observation, the occurrence of non-local changes in such functional outcome could not only be related to a force transmission across myofascial continuity but also be due to other factors such as systemic neural adaptations, i.e., altered stretch tolerance. ...
... Besides its potential relevance under normal conditions, myofascial force transmission could also play a role in the development of overuse disorders. It had been speculated that the occurrence of non-local abnormalities (e.g., increased hamstring stiffness in patients with plantar fasciitis) stems from a pathologically altered/excessive degree of myofascial force transmission (Wilke et al., 2019a). In order to further substantiate this assumption, it seems of interest to conduct similar experiments in both healthy individuals and patients with musculoskeletal disorders. ...
Experiments in cadavers have demonstrated significant mechanical interactions between constituents of myofascial chains. However, evidence for such force transmission effects is scarce under in vivo conditions. The purpose of this trial was to examine the impact of ankle motion on soft tissue displacement of the dorsal thigh. Eleven healthy active individuals (26.8 ± 4.3 years, six males), in prone position and with the knee extended, underwent passive calf stretches (ankle dorsal extension) imposed by an isokinetic dynamometer. High-resolution ultrasound was used to simultaneously capture the displacement of the semimembranosus muscle, which was quantified by means of cross-correlation analysis. Inactivity of the leg muscles was controlled using surface electromyography (EMG). One participant had to be excluded due to major EMG activity during the experiment. According to a one-sample t test testing the difference to the neutral zero position, ankle dorsal extension induced substantial caudal muscle displacements (5.76 ± 2.67 mm, p < 0.0001). Correlation analysis (Spearman), furthermore, revealed a strong association between maximal dorsal extension and semimembranosus motion (rho = 0.76, p = 0.02). In conclusion, the present trial provides initial in vivo evidence for a mechanical force transmission between serially connected skeletal muscles. This means that local alterations of the mechanical tissue properties may modify flexibility in neighboring (superior or inferior) joints.
... Modified alteration in the force transmission from connected structures might lead to overuse injuries [14]. Force transmission in the ITB was mostly determined by its relevant muscles. ...
... The ITB receives direct muscle forces from TFL and Gmax due to the fully and partly anatomical insertions. The changes in myofascial force transmission strategy were associated with the development of overuse injuries in running as the structural linkage of the muscles with connective tissues [14]. Furthermore, long exhaustive running could lead to an unfamiliar and compensating running pattern [35]. ...
Purpose
Long exhausted running causes pain at the lateral femoral epicondyle for some runners. The pain has been revealed to be related to the behavior of the iliotibial band (ITB) during running. The purpose of this study is to examine the effects of in-series musculature on the behavior of the ITB in healthy participants during an exhaustive run.
Methods
Twenty-five healthy participants (15 males, 10 females) were recruited in the current study. All participants performed a 30-minute exhaustive run at a self-selected speed with laboratory-provided footwear. Muscle activities of ITB-related muscles including tensor fascia latae (TFL), gluteus maximus (Gmax), gluteus medius (Gmed), biceps femoris (BF), and vastus lateralis (VL) were recorded using surface electromyography (EMG).
Results
Maximum amplitudes at the initial stage (the first minute), the mid stage (the 15-minute), and the end stage (the 30-minute) were compared during the exhaustive running. Significant decreases (p < 0.05) were observed in the maximum amplitudes of the TFL, Gmax, Gmed, and BF at the mid (decreased by ~ 15%) and end (decreased by ~ 30%) stages compared to the initial stage. The onset and the offset remained unaltered during the running (p ≥ 0.05).
Conclusion
The behavior of the healthy ITB might be altered due to the activities of the in-series musculature. Excessive compression forces might be applied to the lateral femoral epicondyle from the ITB to provide stability for the knee joint during an exhaustive run. The findings could provide a basic understanding of the behavior of healthy ITB.
... One explanation might be an indirect role of myofascial force transmission in reducing pain and improving PFM strength. 35 Because of the structural association between skeletal muscle and collagenous Use of Physical Therapy and Dryneedling for erectile dysfunction journals.sbmu.ac.ir/Neuroscience http connective tissue, it is assumed that increased local stiffness would affect surrounding tissues over time, which subsequently may also become a source of pain and dysfunction. 35 Studies have also shown that exercises away from the site of pain can affect adjacent and related structures. ...
... 35 Because of the structural association between skeletal muscle and collagenous Use of Physical Therapy and Dryneedling for erectile dysfunction journals.sbmu.ac.ir/Neuroscience http connective tissue, it is assumed that increased local stiffness would affect surrounding tissues over time, which subsequently may also become a source of pain and dysfunction. 35 Studies have also shown that exercises away from the site of pain can affect adjacent and related structures. 36,37 In this case, self-stretching exercises of the penis and scar tissue may have reduced the tension of the PFM. ...
Peyronie’s disease (PD) is a connective tissue disorder resulting from abnormal development of fibrotic and non-expandible thickened scar tissue in the penis. Surgical intervention might lead to other complications, including decreased sensation in the penis, persistent pain after surgery, and less-rigid erections. This study presents the physiotherapeutic assessment and management of a 33-year-old man with erectile dysfunction and impaired penile sensation following reconstructive surgeries of the penis. The patient was given physiotherapeutic interventions including dry needling (DN) and subcision of the scar and stretching exercise of the penis. After the 5th visit, the patient reported improvement in symptoms. This case report suggests that dry-needling and subcision techniques can improve pain and sexual well-being in patients with post-plication surgery problems.
... One of the most common pathomechanisms of injuries is an eccentric contraction movement, which damages the contractile fibers and related connective tissues [3]. Another known cause is an overuse injury which can lead to partial or complete tissue injury, or create a chronic inflammatory environment, such as plantar fasciitis or pain that is not always clear to define clinically [4]. With the increase in soft-tissue injuries, the need to find curative strategies grows, which are not necessarily related to surgery. ...
... The need for instrumental application for therapeutic purposes dates back to Greek and Roman antiquity when small metal objects found wide application in therapeutic operations. Furthermore, such tools have also been mentioned by traditional Chinese therapists [4,20]. Instruments have often been used to scrape or squeeze the skin as a means of accelerating blood flow to facilitate the supply and delivery of oxygen and blood to the soft tissues [21]. ...
Instrument-assisted soft-tissue mobilization (IASTM) represents a treatment strategy for soft tissue (skin) and musculoskeletal tissue (myofascia). There are different morphologies of these tools that are used by clinicians and manual therapists for the management of scars, fibrotic formations, muscle-joint pain, and movement limitations. The literature demonstrates the effectiveness of IASTMs in different clinical areas. However, the literature does not consider the use of these tools for the protection of the clinician's hands. The main objective of this article is to draw attention to the fact that IASTM can protect clinicians from professional joint injuries of the hands and can likely become a preventive tool for the operator. Further research is needed to fully determine the positive adaptations in operators who use IASTMs compared to those who do not use them.
... Finally, the deep fascia has been shown to exhibit direct fibrous expansions merging with the underlying skeletal muscle, which means that muscular contraction can selectively tension it [45]. Besides being structurally connected to the underlying muscle, fascia does also provide a direct linkage to other muscles arranged parallel (e.g., from the tibialis anterior to the extensor digitorum) or in-series (e.g., from the gastrocnemius to the hamstrings) [46]. It is therefore tenable to assume that any muscular activity or loading will have pronounced mechanical effects on the connective tissue. ...
... As outlined, DOMS primarily occurs during eccentric loading, and during this active lengthening, high strain forces act upon the skeletal muscle. From a functional point of view, the described continuities to the collagenous soft tissue may represent a shock absorber taking up excessive forces potentially damaging the skeletal muscle [46,47]. However, if going beyond the loading capacity, microscopic or macroscopic damage may occur in the endomysium, perimysium, or deep fascia. ...
Strenuous and unaccustomed exercise frequently lead to what has been coined “delayed onset muscle soreness” (DOMS). As implied by this term, it has been proposed that the associated pain and stiffness stem from micro-lesions, inflammation, or metabolite accumulation within the skeletal muscle. However, recent research points towards a strong involvement of the connective tissue. First, according to anatomical studies, the deep fascia displays an intimate structural relationship with the underlying skeletal muscle and may therefore be damaged during excessive loading. Second, histological and experimental studies suggest a rich supply of algogenic nociceptors whose stimulation evokes stronger pain responses than muscle irritation. Taken together, the findings support the hypothesis that DOMS originates in the muscle-associated connective tissue rather than in the muscle itself. Sports and fitness professionals designing exercise programs should hence consider fascia-oriented methods and techniques (e.g., foam rolling, collagen supplementation) when aiming to treat or prevent DOMS.
... [4] The complex nature of injury suggests that as many contributing factors as possible should be considered during surveillance to improve the effectiveness of injury risk reduction strategies. [5] Notably, in overuse injuries, tissue failure may already be present before the development of pain and performance deficits, with dysfunction in a local area potentially impacting on pathology in neighbouring regions [6]. As such, injury surveillance methods that capture all "physical complaints" may improve the sensitivity of injury surveillance [7] and allow practitioners to consider the magnitude of the symptoms suffered alongside the burden associated with time loss injury [8]. ...
... The delivery design of the OSTRC Questionnaire presents a limitation to the use of the questionnaire for injury "prediction" with multiple injury locations able to be recorded each week. Whilst 90% of all TL hamstring injuries in this study were preceded by a non-TL hamstring complaint, 33% of these preceding complaints included more than one location, and it has been suggested that pain at locations distal to a TL injury site may impact on future injury risk [6]. As such, it is not possible to conclusively determine whether the subsequent TL hamstring injury was always a progression of the reported non-TL hamstring injury, or was related to the non-TL injury in a different location. ...
Objective
To determine the prevalence and impact of non-time loss injuries in semi-professional football.
Methods
218 players completed the Oslo Sports Trauma Research Centre (OSTRC) Questionnaire on Health Problems weekly during the 2016 season (35 weeks), recording the prevalence and impact of time loss (TL) and non-time loss (non-TL) injuries. TL injury and exposure were also collected by a third party as per the Football Consensus statement. The relative risk (RR) of a TL injury within 7 days of a self-reported non-TL injury was determined, with associated predictive power calculated.
Results
The risk of TL injury was 3.6 to 6.9 × higher when preceded by ‘minor’ and ‘moderate’ non-TL complaints, respectively, and good predictive power (22.0–41.8%) was observed (AUC range = 0.73 to 0.83). Compliant responders (80% of completed OSTRC questionnaires) showed a mean self-reported weekly injury prevalence (TL and non-TL combined) of 33% (95% CI – 31.4% to 34.6%) with 28% (CI – 26.4% to 29.6%) attributed to non-TL injury.
Conclusion
Over a quarter of players on average, report a physical complaint each week that does not prevent them from participating in training or match play. A non-TL injury was shown to be useful in identifying individual players at an increased risk of a TL injury.
... Common structural and function dysfunctions include but are not limited to patellofemoral pain syndrome (PFPS), Achilles' tendonitis, iliotibial band syndrome (ITBS), ligamentous and muscle tears, muscle sprains/strains, stress fractures, pes planus, plantar fasciitis, and shin splints. The most common overuse injuries, which includes tendinopathies, ITBS, plantar fasciitis, and stress fractures, make up 30-90 % of all musculoskeletal disorders seen in athletes, and research is often targeting these areas [2]. Although intrinsic factors such as anatomy, gender, and age do affect running injuries, there are several extrinsic running factors that can be managed that influence injury prevention and rehabilitation. ...
Context
Runners often experience acute/chronic pain due to pre-existing structural somatic dysfunction and/or acquired various overuse injuries of the lower extremity, specifically affecting the ligaments, tendons, muscles, and bones. Common structural and function dysfunctions include but are not limited to patellofemoral pain syndrome (PFPS), Achilles tendonitis, iliotibial band syndrome (ITBS), ligamentous and muscle tears, muscle sprains/strains, stress fractures, pes planus, plantar fasciitis, and shin splints.
Objectives
The purpose of this study is to assess the correlation between acute and chronic pain, overuse injuries, and observational and palpatory findings upon evaluation to establish common trends of somatic dysfunctions and determine possible etiology of the pain/injury.
Methods
A total of 103 individuals were recruited (54.4% female, 45.6% male) aged 23–67 years old who consistently run at least 1 mile each week. They were categorized based on their weekly mileage – Novice (1–5 miles per week), Moderate (6–15), Advanced (15+) – with the intention to have a diversity of running types and to assess the data at various levels of commitment to running. The average was 7.8 miles/week with the range at 1 to 28 miles per week. The subjects included Touro students and individuals in the community. A history was collected through an anonymous survey on the individual’s running habits, chronic/acute injuries, and any other relevant medical information. Data analyzing investigators were blinded to subjects’ identifying information. Additionally, an osteopathic assessment was performed by two student investigators for reliability purposes and conducted under supervision by a board-certified osteopathic physician.
Results
Analysis of the data suggested an existing correlation between the number of somatic dysfunctions and years of running. A slight correlation was found between somatic dysfunctions and miles per week, sports injuries, time per week, and lower extremity pain. Finally, statistical correlations were also identified between the presence of pes planus and limb length discrepancy with three distinct muscular hypertonicities.
Conclusions
Runners’ pains and injuries of the lower extremity are complex, and injury treatment and prevention is equally multifaceted. An association was found between both pes planus and limb length discrepancy with lower extremity muscle hypertonicity, suggesting the interrelated nature of these somatic dysfunctions. The survey concluded that many runners continue to run in pain and/or after significant injury but do not necessarily capitalize on existing support such as fitted shoes, custom arches, and osteopathic treatment that may help to minimize their risk of or treat injury. The intention of the research is to bring awareness to practitioners to the most common somatic dysfunctions such that they can recommend runners to obtain gait analyses and/or osteopathic treatments, which may not only alleviate injuries faster but also prevent future injury.
... While we cannot adjust the POI to account for this variability, it is essential to understand this additional workload due to daily movements to explain differences in injury rates. Overuse injuries comprise at least 70% of all injuries and MSKIs and 65% of all medically nondeployable active duty soldiers [20,21]. MSKIs become a higher risk with excessive loading, inadequate recovery, and under-preparedness for load changes [22]. ...
Background:
During periods of high-volume vigorous exercise, United States Marine Corps recruits often experience musculoskeletal injuries. While the program of instruction (POI) for basic training is a defined training volume, the total workload of boot camp, including movements around the base, is unknown.
Objective:
The present study aimed to quantify the daily total workload, energy expenditure, and sleep during basic recruit training at Marine Corps Recruit Depot (MCRD) San Diego.
Methods:
Eighty-four male recruits from MCRD San Diego wore wrist wearable physiological monitors to capture their complete workload (mileage from steps), energy expenditure, and sleep throughout the 10-week boot camp.
Results:
Marine recruits traveled an average of 11.5±3.4 miles per day (M±SD), expended 4105±823 kcal per day, and slept an average of 5 : 48±1 : 06 hours and minutes per night. While the POI designates a total of 46.3 miles of running and hiking, the actual daily average miles yielded approximately 657.6±107.2 miles over the 10-week boot camp.
Conclusion:
Recruit training requires high physical demand and time under tension due to the cumulative volume of movements around base in addition to the POI planned physical training.
... Percussion mechanical massage and passive rest did not affect muscle stiffness (p < 0.05). An increase in local stiffness may affect adjacent tissues via collagenous connective tissue [63]. It is possible that when penetrated through muscle, applied vibrations had more positive results than percussions. ...
Background and Objectives: In many sports, maintaining muscle work at an optimal level despite fatigue is crucial. Therefore, it is essential to discover the most efficient way of recovery. This study aimed to evaluate and compare the acute effects of four different recovery methods on muscle neuromechanical properties. Materials and Methods: The research was conducted using a randomized, quasi-experimental, repeated-measures design. Fourteen healthy and active male students of the Faculty of Sport and Physical Education (age 25.1 ± 3.9 years) were included in this study. The tensiomyography was used to evaluate muscle responses after four different types of short-term recovery methods (passive rest, percussive mechanical, vibro-mechanical, and manual massage) on the rectus femoris muscle on four occasions: baseline, post fatigue, post recovery and prolonged recovery. Results: The ANOVA revealed that muscle fatigue decreased maximal vertical muscle displacement (Dm) and muscle contraction time (Tc) in post fatigue compared to the baseline. The most important finding shows that only the vibro-mechanical massage resulted in an increase in Tc in the prolonged recovery compared to the post fatigue (p = 0.028), whereas only manual massage showed no differences in Dm from the baseline in post-recovery (p = 0.148). Moreover, both manual and vibro-mechanical massages increased Dm and Tc in prolonged recovery, indicating no differences from the baseline (all p > 0.05), thus showing signs of muscle recovery. Percussion mechanical massage and passive rest did not show indices of muscle recovery. Conclusions: Manual massage could induce immediate positive changes in Dm by reducing muscle stiffness. In addition, vibro-mechanical and manual massage improved muscle tissue by rapidly returning Dm and Tc values to baseline at prolonged recovery measurement (5 min after the fatigue protocol). These findings can benefit sports practitioners, and physical therapists in developing the best recovery method after muscle fatigue.
... In fact, in overuse injuries, tissue failure can already be present before the development of pain or performance decrements. 41 Weekly incident injuries recorded by the third party and physiotherapy methods tracked relatively similarly throughout BMT, potentially because of the third-party recording recruits who were on training restrictions, which were likely provided by the physiotherapists. In weeks when fewer incident injuries were recorded by the third party in comparison to physiotherapy, limited physical training sessions (≤3 sessions per week) were conducted; accordingly, as no physical training sessions were scheduled in week 10, no third-party incident injuries were recorded. ...
Introduction
The injury definitions and surveillance methods commonly used in Army basic military training (BMT) research may underestimate the extent of injury. This study therefore aims to obtain a comprehensive understanding of injuries sustained during BMT by employing recording methods to capture all physical complaints.
Materials and methods
Six hundred and forty-six recruits were assessed over the 12-week Australian Army BMT course. Throughout BMT injury, data were recorded via (1) physiotherapy reports following recruit consultation, (2) a member of the research team (third party) present at physical training sessions, and (3) recruit daily self-reports.
Results
Two hundred and thirty-five recruits had ≥1 incident injury recorded by physiotherapists, 365 recruits had ≥1 incident injury recorded by the third party, and 542 recruits reported ≥1 injury-related problems via the self-reported health questionnaire. Six hundred twenty-one, six hundred eighty-seven, and two thousand nine hundred sixty-four incident injuries were recorded from a total of 997 physiotherapy reports, 1,937 third-party reports, and 13,181 self-reported injury-related problems, respectively. The lower extremity was the most commonly injured general body region as indicated by all three recording methods. Overuse accounted for 79% and 76% of documented incident injuries from physiotherapists and the third party, respectively.
Conclusions
This study highlights that injury recording methods impact injury reporting during BMT. The present findings suggest that traditional injury surveillance methods, which rely on medical encounters, underestimate the injury profile during BMT. Considering accurate injury surveillance is fundamental in the sequence of injury prevention, implementing additional injury recording methods during BMT may thus improve injury surveillance and better inform training modifications and injury prevention programs.
... 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]. ...
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.
... The thoracolumbar fascia is an important structure related to the transmission of force as well as synchronism between the pelvic and scapular girdle [19]. All three layers of the deep fascia of the trunk are found in the dorsal region and are reorganized involving the posterior muscle groups. ...
The fascial system is a link between the various body systems. Understanding the embryonic formation of the fascial system contributes to understanding the development of the whole body, helping to understand clinical phenomena. The text presents the concept of the fascial system and its interactions with the neural system. We describe the formation of musculoskeletal fascia from somites and mesenchymal cells of the cranial neural crest. Differences in the formation of the head, neck, trunk, and limbs and their respective embryonic relationships are presented.
We detail the formation of visceral fascia and their corresponding innervations, from the tongue to the final portion of the digestive tract; the development of the genitourinary system that occurs later in the celomic cavity; and the formation of the cardiocirculatory and respiratory systems, with the development of their respective envelopes, associated with the corresponding innervation. The text covers the embryology of neural fasciae, both at the level of the central and peripheral nervous system. Finally, the development of derme and pannicular fascia is presented.
The relaxation of trapezius muscles is widely believed to alleviate fatigue or injury of the trapezius muscles and reduce the risk of shoulder and neck pain. This study aims to examine the effects of different muscle relaxation techniques on the physical properties of the trapezius muscle and to explore how changes in the physical properties of the upper trapezius muscle affect those of the middle trapezius muscle. Twenty-four healthy males (mean age: 23.08 ± 0.97 years; height: 172.42 ± 4.61 cm; weight: 66.38 ± 6.68 kg; and body mass index: 22.30 ± 1.81 kg/m ² ), randomly divided into four groups: stretching relaxation group (ST, n = 6), mechanical vibration massage (MV, n = 6), pulse massage (PU, n = 6), and control (CO, n = 6). Measurements using the Myoton digital muscle assessment system were conducted daily over 2 weeks. The experimental groups demonstrated a notable decrease in tension and stiffness, accompanied by heightened elasticity in the upper trapezius muscles. Conversely, the control group exhibited contrasting trends. Although no significant variances were detected among the relaxation techniques, all proved efficacious compared to the control group ( P < 0.05). Moreover, relaxation of the upper trapezius muscles significantly influenced the middle trapezius muscles ( P < 0.05). Various relaxation methods positively influenced trapezius muscle attributes over 2 weeks, with inter-regional effects noted.
Neurology and connective tissue are intimately interdependent systems and are critical in regulating many of the body’s systems. Unlocking their multifaceted relationship can transform clinical understanding of the mechanisms involved in multisystemic regulation and dysregulation. The fascial system is highly innervated and rich with blood vessels, lymphatics, and hormonal and neurotransmitter receptors. Given its ubiquity, fascia may serve as a “watchman,” receiving and processing information on whole body health. This paper reviews what constitutes fascia, why it is clinically important, and its contiguous and interdependent relationship with the nervous system. Unquestionably, fascial integrity is paramount to human locomotion, interaction with our environment, bodily sense, and general physical and emotional wellbeing, so an understanding of the fascial dysregulation that defines a range of pathological states, including hypermobility syndromes, autonomic dysregulation, mast cell activation, and acquired connective tissue disorders is critical in ensuring recognition, research, and appropriate management of these conditions, to the satisfaction of the patient as well as the treating practitioner.
Foot drop is one of the most common causes of disability among individuals and primarily caused by common peroneal nerve entrapment followed by orthopedic and neurologic disorders i.e. cerebrovascular accident, guillain-barre syndrome, peripheral neuropathy etc. which leads to lack of ankle dorsiflexion, reduced muscle strength and even functional disability. The calf muscle flossing technique using voodoo band on common peroneal nerve in foot drop along with conventional therapy is much helpful in regain ankle mobility, improved muscle strength and also minimize disability in early phase of recovery. 35 numbers of subjects with foot drop were selected as patients who come under the inclusion criteria. out of which 3 patients were denied for consent and 2 subjects' dropout prior to completion of intervention period. total N-30 subjects were allocated into 2 groups i.e., 15 subjects in (Group A) and 15 subjects in (Group B) through simple random sampling method. Out of 30 subjects there were 20 male patients and 10 female patients.
Aim
Previous stretching studies mostly investigated effects on the skeletal muscle but comprehensive explorations regarding the role of the connective tissue are scarce. Since the deep fascia has been demonstrated to be sensitive to mechanical tension, it was hypothesized that the fascia would also respond to stretching, contributing to enhanced range of motion (ROM).
Methods
Forty (40) recreationally active participants (male: n = 25, female: n = 15) were included in the randomized controlled cross-over trial and allocated to different groups performing 5 min static (STAT) or dynamic (DYN) plantar flexor stretching or control condition (CC) in a random order. Pre- and immediately post-intervention, muscle and fascia stiffness, as well as muscle and fascia thickness were measured using high-resolution ultrasound and strain elastography. ROM was assessed in the ankle joint via the knee to wall test (KtW) and goniometer.
Results
STAT reduced both, muscle and fascia stiffness (d = 0.78 and 0.42, p < 0.001, respectively), while DYN did not reduce stiffness compared to the control condition (p = 0.11–0.41). While both conditions showed significant increases in the KtW (d = 0.43–0.46, p = 0.02–0.04), no significant differences to the CC were observed for the isolated ROM testing (p = 0.09 and 0.77). There was a small correlation between fascia stiffness decreases and ROM increases (r = − 0.25, p = 0.006) but no association was found between muscle stiffness decreases and ROM increases (p = 0.13–0.40).
Conclusion
Our study is the first to reveal stretch-induced changes in fascia stiffness. Changes of fascia`s but not muscle`s mechanical properties may contribute to increased ROM following stretching.
Background
Due to the lack of further studies on the influence of age factors on plantar fasciitis, this study evaluates the characteristic observation points of magnetic resonance imaging in various age cohorts of patients with plantar fasciitis to help diagnosis.
Methods
A retrospective analysis of 160 cases of plantar fasciitis patients and normal subjects (who have the disease unrelated to plantar fasciitis) who have undergone an MRI examination in our institution. The two groups were separately divided into young adult subjects (36 to 44 years old), middle age adult subjects (45 to 59 years old), and older adult subjects (60 to 79 years old). Data was gathered regarding plantar fascia thickness, the coronal length of the plantar fascia at the calcaneal origin, the signal intensity of plantar fascia and surrounding structures, and the presence or absence of plantar calcaneal spurs, all of which were assessed objectively by the investigators.
Results
There were statistical differences in the thickness of plantar fascia between two groups of three age cohorts (Older adult patients: 0.59 ± 0.09 cm; Middle age adult patients: 0.49 ± 0.09 cm; Young adult patients: 0.47 ± 0.05 cm) (all p < 0.001). In addition, there were also statistical differences in the high signal intensity changes of the plantar fascia and surrounding soft tissues between two groups of three age cohorts (all p < 0.001). In older adult plantar fasciitis patients, with regard to plantar calcaneal spur discovery, there was a statistical difference between the two groups (Chi-square = 12.799. df = 1. p < 0.001).
Conclusion
In plantar fasciitis cases where a diagnosis is difficult, abnormalities in the soft tissue surrounding the plantar fascia in patients of low age are noteworthy. In older adult patients, the discovery of plantar calcaneal spurs with abnormal thickening of plantar fascia deserves attention, and abnormal MRI findings are more manifest. But the final diagnosis should be based on the medical history.
Level of Evidence
Level 3.
Fascial tissues form a ubiquitous network throughout the whole body, which is usually regarded as a passive contributor to biomechanical behavior. We aimed to answer the question, whether fascia may possess the capacity for cellular contraction which, in turn, could play an active role in musculoskeletal mechanics. Human and rat fascial specimens from different body sites were investigated for the presence of myofibroblasts using immunohistochemical staining for alpha‐smooth muscle actin (n= 31 donors, n=20 animals). In addition, mechanographic force registrations were performed on isolated rat fascial tissues (n=8 to n=18), which had been exposed to pharmacological stimulants. The density of myofibroblasts was increased in the human lumbar fascia in comparison to fasciae from the two other regions examined in this study: fascia lata and plantar fascia (H(2) = 14.0, p < 0.01). Mechanographic force measurements revealed contractions in response to stimulation by fetal bovine serum, the thromboxane A2
analog U46619, TGF‐β1, and mepyramine, while challenge by botulinum toxin type C3–used as a Rho kinase inhibitor– provoked relaxation (p<.05). In contrast, fascial tissues were insensitive to angiotensin II and caffeine (p>.05). A positive correlation between
myofibroblast density and contractile response was found (r=.83, p<.001). The hypothetical application of the registered forces to human lumbar tissues predicts a potential impact below the threshold for mechanical spinal stability but strong enough to possibly alter motoneuronal coordination in the lumbar region. It is concluded that tension of myofascial tissue is actively regulated by myofibroblasts with the potential to impact active musculoskeletal dynamics.
Background
The relationship between specific types of stressors (eg, teammates, coach) and acute versus overuse injuries is not well understood.
Objective
To examine the roles of different types of stressors as well as the effect of motivational climate on the occurrence of acute and overuse injuries.
Methods
Players in the Norwegian elite female football league (n=193 players from 12 teams) participated in baseline screening tests prior to the 2009 competitive football season. As part of the screening, we included the Life Event Survey for Collegiate Athletes and the Perceived Motivational Climate in Sport Questionnaire (Norwegian short version). Acute and overuse time-loss injuries and exposure to training and matches were recorded prospectively in the football season using weekly text messaging. Data were analysed with Bayesian logistic regression analyses.
Results
Using Bayesian logistic regression analyses, we showed that perceived negative life event stress from teammates was associated with an increased risk of acute injuries (OR=1.23, 95% credibility interval (1.01 to 1.48)). There was a credible positive association between perceived negative life event stress from the coach and the risk of overuse injuries (OR=1.21, 95% credibility interval (1.01 to 1.45)).
Conclusions
Players who report teammates as a source of stress have a greater risk of sustaining an acute injury, while players reporting the coach as a source of stress are at greater risk of sustaining an overuse injury. Motivational climate did not relate to increased injury occurrence.
Background
Low back pain (LBP) is an increasingly common condition worldwide with significant costs associated with its management. Identification of musculoskeletal risk factors that can be treated clinically before the development of LBP could reduce costs and improve the quality of life of individuals. Therefore the aim was to systematically review prospective cohort studies investigating lower back and / or lower limb musculoskeletal risk factors in the development of LBP.
Methods
MEDLINE, EMBASE, AMED, CINAHL, SPORTDiscus, and the Cochrane Library were searched from inception to February 2016. No age, gender or occupational restrictions of participants were applied. Articles had to be published in English and have a 12 month follow-up period. Musculoskeletal risk factors were defined as any osseous, ligamentous, or muscular structure that was quantifiably measured at baseline. Studies were excluded if participants were pregnant, diagnosed with cancer, or had previous low back surgery. Two authors independently reviewed and selected relevant articles. Methodological quality was evaluated independently by two reviewers using a generic tool for observational studies.
Results
Twelve articles which evaluated musculoskeletal risk factors for the development of low back pain in 5459 participants were included. Individual meta-analyses were conducted based on risk factors common between studies. Meta-analysis revealed that reduced lateral flexion range of motion (OR = 0.41, 95% CI 0.24-0.73, p = 0.002), limited lumbar lordosis (OR = 0.73, 95% CI 0.55-0.98, p = 0.034), and restricted hamstring range of motion (OR = 0.96, 95% CI 0.94-0.98, p = 0.001) were significantly associated with the development of low back pain. Meta-analyses on lumbar extension range of motion, quadriceps flexibility, fingertip to floor distance, lumbar flexion range of motion, back muscle strength, back muscle endurance, abdominal strength, erector spinae cross sectional area, and quadratus lumborum cross sectional area showed non-significant results.
Conclusion
In summary, we found that a restriction in lateral flexion and hamstring range of motion as well as limited lumbar lordosis were associated with an increased risk of developing LBP. Future research should aim to measure additional lower limb musculoskeletal risk factors, have follow up periods of 6-12 months, adopt a standardised definition of LBP, and only include participants who have no history of LBP.
Electronic supplementary material
The online version of this article (doi:10.1186/s12891-017-1534-0) contains supplementary material, which is available to authorized users.
Athletes participating in elite sports are exposed to high training loads and increasingly saturated competition calendars. Emerging evidence indicates that poor load management is a major risk factor for injury. The International Olympic Committee convened an expert group to review the scientific evidence for the relationship of load (defined broadly to include rapid changes in training and competition load, competition calendar congestion, psychological load and travel) and health outcomes in sport. We summarise the results linking load to risk of injury in athletes, and provide athletes, coaches and support staff with practical guidelines to manage load in sport. This consensus statement includes guidelines for (1) prescription of training and competition load, as well as for (2) monitoring of training, competition and psychological load, athlete well-being and injury. In the process, we identified research priorities.
The present review aims to provide a systematic overview on tensile transmission along myofascial chains based on anatomical dissection studies and in vivo experiments. Evidence for the existence of myofascial chains is growing, and the capability of force transmission via myofascial chains has been hypothesized. However, there is still a lack of evidence concerning the functional significance and capability for force transfer. A systematic literature research was conducted using MEDLINE (Pubmed), ScienceDirect and Google Scholar. Studied myofascial chains encompassed the superficial backline (SBL), the back functional line (BFL) and the front functional line (FFL). Peer-reviewed human dissection studies as well as in vivo experiments reporting intermuscular tension transfer between the constituents of a myofascial chain were included. To assess methodic quality, two independent investigators rated studies by means of validated assessment tools (QUACS and PEDro Scale). The literature research identified 1022 articles. Nine studies (moderate to excellent methodological quality) were included. Concerning the SBL and the BFL, there is moderate evidence for force transfer at all three transitions (based on six studies), and one of two transitions (three studies). One study yields moderate evidence for a slight, but not significant force transfer at one transition in the FFL. The findings of the present study indicate that tension can be transferred between some of the examined adjacent structures. Force transfer might have an impact in overuse conditions as well as on sports performance. However, different methods of force application and measurement hinder the comparability of results. Considering anatomical variations in the degree of continuity and histological differences of the linking structures is crucial for interpretation. Future studies should focus on the in vivo function of myofascial continuity during isolated active or passive tissue tensioning.
Purpose:
Recent research indicates that the skeletal muscles of the human body do not function as independent actuators. Instead, they seem to be linked by connective tissue forming myofascial chains. While the existence of such meridians has been demonstrated for the ventral and the dorsal side of the body, no data are available for morphological fusion of lateral muscles. This study aimed to provide evidence for the inferior part of the lateral myofascial chain.
Methods:
Fourteen legs (7 embalmed cadavers, four ♂, 86 ± 7 years) were dissected to reveal a potential myofascial continuity between the fibularis longus muscle, more detailed, its fascia, and the iliotibial tract (ITT). Three investigators judged the general existence as well as the degree and characteristics of the continuity. If an anatomical continuity was evident, strain was applied to both structures in order to evaluate the tissues' ability for tensile transmission.
Results:
An indirect connection between the iliotibial tract and the fascia of the fibularis longus muscle was found: in all examined legs, the ITT fused strongly with the crural fascia. The latter was hardly separable from the fibularis longus fascia. Application of strain to the ITT caused local movement in the crural fascia and the underlying fascia of the fibularis muscle.
Conclusions:
The iliotibial tract fuses firmly with the crural fascia and the degree of continuity suggests that moderate amounts of strain might be transmitted. However, biomechanical studies precisely quantifying this tensile transmission are warranted in order to estimate the relevance of the linkage for the locomotor system.
Many tendon injuries are believed to result from repetitive motion or overuse, leading to the accumulation of micro-damage over time. In vitro fatigue loading can be used to characterise damage during repeated use and investigate how this may relate to the aetiology of tendinopathy.
This study considered the effect of fatigue loading on fascicles from two functionally distinct bovine tendons: the digital extensor and deep digital flexor. Micro-scale extension mechanisms were investigated in fascicles before or after a period of cyclic creep loading, comparing two different measurement techniques – the displacement of a photo-bleached grid and the use of nuclei as fiducial markers.
Whilst visual damage was clearly identified after only 300 cycles of creep loading, these visual changes did not affect either gross fascicle mechanics or fascicle microstructural extension mechanisms over the 900 fatigue cycles investigated. However, significantly greater fibre sliding was measured when observing grid deformation rather than the analysis of nuclei movement. Measurement of microstructural extension with both techniques was localised and this may explain the absence of change in microstructural deformation in response to fatigue loading. Alternatively, the data may demonstrate that fascicles can withstand a degree of matrix disruption with no impact on mechanics. Whilst use of a photo-bleached grid to directly measure the collagen is the best indicator of matrix deformation, nuclei tracking may provide a better measure of the strain perceived directly by the cells.
Cerebral palsy (CP) of the spastic type is a neurological disorder characterized by a velocity-dependent increase in tonic stretch reflexes with exaggerated tendon jerks. Secondary to the spasticity, muscle adaptation is presumed to contribute to limitations in the passive range of joint motion. However, the mechanisms underlying these limitations are unknown. Using biopsies, we compared mechanical as well as histological properties of flexor carpi ulnaris muscle (FCU) from CP patients (n = 29) and healthy controls (n = 10). The sarcomere slack length (mean 2.5 µm, SEM 0.05) and slope of the normalized sarcomere length-tension characteristics of spastic fascicle segments and single myofibre segments were not different from those of control muscle. Fibre type distribution also showed no significant differences. Fibre size was significantly smaller (1933 µm2, SEM 190) in spastic muscle than in controls (2572 µm2, SEM 322). However, our statistical analyses indicate that the latter difference is likely to be explained by age, rather than by the affliction. Quantities of endomysial and perimysial networks within biopsies of control and spastic muscle were unchanged with one exception: a significant thickening of the tertiary perimysium (3-fold), i.e. the connective tissue reinforcement of neurovascular tissues penetrating the muscle. Note that this thickening in tertiary perimysium was shown in the majority of CP patients, however a small number of patients (n = 4 out of 23) did not have this feature. These results are taken as indications that enhanced myofascial loads on FCU is one among several factors contributing in a major way to the aetiology of limitation of movement at the wrist in CP and the characteristic wrist position of such patients.
Study design:
Cross-sectional laboratory study.
Objectives:
To assess differences in hip strength, iliotibial band length, and hip and knee mechanics during running between male runners with iliotibial band syndrome (ITBS) and healthy controls.
Background:
Flexibility, strength, and running mechanics are commonly assessed in patients with ITBS. However, these variables have not been evaluated concurrently in this population.
Methods:
Thirty-four men participated (17 healthy, 17 ITBS). Hip strength was measured with a handheld dynamometer, and iliotibial band length was assessed using an inclinometer while performing the Ober test. Kinetic and 3-D kinematic data were obtained during running. Kinematic variables of interest included frontal and transverse plane hip and knee joint angles during early stance. Independent-samples t tests, as well as effect sizes, were used to assess group differences.
Results:
Compared to the control group, persons with ITBS had a significantly lower Ober measurement (1.2°), weaker hip external rotators (1.2 Nm/kg), greater hip internal rotation (3.7°), and greater knee adduction (3.6°). However, only hip internal rotation and knee adduction exceeded the minimal detectable difference value.
Conclusion:
Our results suggest that intervention strategies that target neuromuscular control of the hip and knee may be indicated for males with ITBS.
Skeletal muscle fibrosis can be a devastating clinical problem that arises from many causes, including primary skeletal muscle tissue diseases, as seen in the muscular dystrophies, or can be secondary to events that include trauma to muscle or brain injury. The cellular source of activated fibroblasts (myofibroblasts) may include resident fibroblasts, muscle adult stem cells, inflammatory or perivascular cells depending upon the model studied. Even though it is likely that there is no single source for the myofibroblasts, a common mechanism for the production of fibrosis is via the TGFβ/PSmad3 pathway. This pathway and its downstream targets thus provide loci for anti-fibrotic therapies as do methods for blocking the transdifferentiation of progenitors into activated fibroblasts. A structural model for the extracellular collagen network of skeletal muscle is needed to facilitate measurements of collagen content, morphology and gene expression to be related to mechanical properties. Approaches used to study fibrosis in tissues, such as lung, kidney and liver, need to be applied to studies of skeletal muscle so as to identify ways to prevent or even cure the devastating maladies of skeletal muscle.
Background:
The aim of this study was to determine whether tightness of the posterior muscles of the lower extremity was associated with plantar fasciitis.
Methods:
A total of 100 lower limbs of 100 subjects, 50 with plantar fasciitis and 50 matching controls were recruited. Hamstring and calf muscles were evaluated through the straight leg elevation test, popliteal angle test, and ankle dorsiflexion (knee extended and with the knee flexed). All variables were compared between the 2 groups. In addition, ROC curves, sensitivity, and specificity of the muscle contraction tests were also calculated to determine their potential predictive powers.
Results:
Differences between the 2 groups for the tests used to assess muscular shortening were significant (P < .001) in all cases. The straight leg elevation test and ankle dorsiflexion with the knee extended presented respective sensitivities of 94% and 100% and specificities of 82% and 96% as diagnostic tests for the participants in this study.
Conclusion:
Tightness of the posterior muscles of the lower limb was present in the plantar fasciitis patients, but not in the unaffected participants.
Clinical relevance:
The results of this study suggest that therapists who are going to employ a stretching protocol for treatment of plantar fasciitis should look for both hamstring as well as triceps surae tightness. Stretching exercise programs could be recommended for treatment of plantar fasciitis, focusing on stretching the triceps surae and hamstrings, apart from an adequate tissue-specific plantar fascia-stretching protocol.
Level of evidence:
Level III, case control study.
Background:
Current methods for injury registration in sports injury epidemiology studies may substantially underestimate the true burden of overuse injuries due to a reliance on time-loss injury definitions.
Objective:
To develop and validate a new method for the registration of overuse injuries in sports.
Methods:
A new method, including a new overuse injury questionnaire, was developed and validated in a 13-week prospective study of injuries among 313 athletes from five different sports, cross-country skiing, floorball, handball, road cycling and volleyball. All athletes completed a questionnaire by email each week to register problems in the knee, lower back and shoulder. Standard injury registration methods were also used to record all time-loss injuries that occurred during the study period.
Results:
The new method recorded 419 overuse problems in the knee, lower back and shoulder during the 3-month-study period. Of these, 142 were classified as substantial overuse problems, defined as those leading to moderate or severe reductions in sports performance or participation, or time loss. Each week, an average of 39% of athletes reported having overuse problems and 13% reported having substantial problems. In contrast, standard methods of injury registration registered only 40 overuse injuries located in the same anatomical areas, the majority of which were of minimal or mild severity.
Conclusion:
Standard injury surveillance methods only capture a small percentage of the overuse problems affecting the athletes, largely because few problems led to time loss from training or competition. The new method captured a more complete and nuanced picture of the burden of overuse injuries in this cohort.
Although overuse injuries are gaining attention, epidemiologic studies on overuse injuries in male and female collegiate athletes are lacking.
To report the epidemiology of overuse injuries sustained by collegiate athletes and to compare the rates of overuse and acute injuries.
Descriptive epidemiology study.
A National Collegiate Athletic Association Division I university.
A total of 1317 reported injuries sustained by 573 male and female athletes in 16 collegiate sports teams during the 2005-2008 seasons.
The injury and athlete-exposure (AE) data were obtained from the Sports Injury Monitoring System. An injury was coded as either overuse or acute based on the nature of injury. Injury rate was calculated as the total number of overuse (or acute) injuries during the study period divided by the total number of AEs during the same period.
A total of 386 (29.3%) overuse injuries and 931 (70.7%) acute injuries were reported. The overall injury rate was 63.1 per 10 000 AEs. The rate ratio (RR) of acute versus overuse injuries was 2.34 (95% confidence interval [CI] = 2.05, 2.67). Football had the highest RR (RR = 8.35, 95% CI = 5.38, 12.97), and women's rowing had the lowest (RR = 0.75, 95% CI = 0.51, 1.10). Men had a higher acute injury rate than women (49.8 versus 38.6 per 10 000 AEs). Female athletes had a higher rate of overuse injury than male athletes (24.6 versus 13.2 per 10,000 AEs). More than half of the overuse injuries (50.8%) resulted in no time loss from sport.
Additional studies are needed to examine why female athletes are at greater risk for overuse injuries and identify the best practices for prevention and rehabilitation of overuse injuries.
The purpose of this prospective cohort study was to determine if hamstring tightness was an increased risk in plantar fasciitis. It was thought that there is an increased risk of plantar fasciitis when hamstring tightness is present. A total of 105 patients (68 women, 37 men) were included in the study, 79 of whom were diagnosed with plantar fasciitis. Body mass index (BMI) was calculated and the presence of plantar fasciitis, equinus, and calcaneal spurs were assessed. The popliteal angle was measured using standard diagnostic techniques. Without controlling for covariates, BMI, the presence of a calcaneal spur, tightness in the gastrocnemius, gastrocnemius-soleus, and hamstring all had statistically significant association with plantar fasciitis. After controlling for covariates, patients with hamstring tightness were about 8.7 times as likely to experience plantar fasciitis (P < .0001). Patients with BMI >35 were approximately 2.4 times as likely to experience plantar fasciitis compared with those with BMI <35 (P = .04). This study demonstrates that hamstring tightness plays a significant role in the presence of plantar fasciitis and should be addressed along with equinus and obesity when providing treatment to patients with this diagnosis.
The knowledge regarding the structural details of deep fascia remains inadequate. It was described to be relatively avascular having predominantly protective function. Anatomical and surgical studies revealed that it had associated vascular arcade and hence incorporated it to ascertain additional vascularity to the flaps. However, not much importance has been directed towards the detailed study of the various constituents of deep fascia in order to explain its physiological and clinical implications. Therefore, this study was undertaken to unveil these details.
Fifty fresh specimens of human deep fascia overlying the gastrocnemius muscle were analyzed regarding the (i) vasculature, (ii) matrix, and (iii) other structural elements. The deep fascia was procured in three forms; (a) both the layers, (b) superficial layer, and (c) deep layer. Detail study was conducted by light, confocal, and electron microscopy.
Under light microscopy, blood vessels including capillaries were seen associated with both the layers. Perforators traversing the intra-fascial plane could be visualized. Confocal microscope optical sections showed well-organized bright fluorescent collagen fibers and nuclei of various cells. Electron microscopic evaluation revealed many interesting constituents which are relatively unknown to the anatomist and clinicians. There were arterioles, capillaries, venules, lymphatics, nerves, mast cells, and myofibroblasts apart from collagen and elastic fibers.
The detail structural analysis of deep fascia provided the clue to its rich vascularity and other structural constituents. They all contribute to enhance the vascularity and maintenance of the physiological functions of fasciocutaneous, adipofascial, and fascial flaps, frequently used for reconstructions. Thus, incorporation of deep fascia in the flaps during reconstruction is highly beneficial for ensuring optimal vascularity.
Summary. Sacroiliac joint dysfunction is often overlooked as a possible cause of low back pain. This is due to the use of reductionistic anatomical models. From a kinematic point of view, topographic anatomical models are generally inadequate since they categorize pelvis, lower vertebral column and legs as distinct entities. This functional-anatomical study focuses on the question whether anatomical connections between the biceps femoris muscle and the sacrotuberous ligament are kinematically useful. Forces applied to the tendon of the biceps femoris muscle, simulating biceps femoris muscle force, were shown to influence sacrotuberous ligament tension. Since sacrotuberous ligament tension influences sacroiliac joint kinematics, hamstring training could influence the sacroiliac joint and thus low back kinematics. The clinical implications with respect to 'short' hamstrings, pelvic instability and walking are discussed.
The goal of the study was to determine the rate of running-associated tendinopathy in light of the amount of time training and other risk factors.
291 elite runners (average age 42 +/- 9 years) who ran an average of 65.2 +/- 28.3 km/week were included with an overall distance of 9,980,852 km (34,416 km/athlete). Descriptive statistics with Chi2-Test, Fisher-Exact-Test and Mann-Whitney-Test were used to calculate relative risks (RR).
The overall injury rate was 0.08/1000 km (2.93/athlete). Overuse injuries (0.07/1000 km) were more frequent than acute injuries (0.01/1000 km). Achilles tendinopathy was the predominant injury (0.02/1000 km) followed by anterior knee pain (0.01/1000 km), and shin splints (0.01/1000 km). Achilles tendon rupture was rarely encountered (0.001/1000 km). At some time, 56.6% of the athletes had an Achilles tendon overuse injury, 46.4% anterior knee pain, 35.7% shin splints, and 12.7% had plantar fasciitis. Mid-portion Achilles tendinopathy was more common (0.01/1000 km) than insertional (0.005/1000 km). An asphalt running surface decreased mid-portion tendinopathy risk (RR 0.47, p = 0.02). In contrast, sand increased the relative risk for mid-portion Achilles tendinopathy tenfold (RR 10, CI 1.12 to 92.8, p = 0.01). Runners with more than 10 years experience had an increased risk (RR 1.6, p = 0.04) for Achilles tendinopathy.
Achilles tendinopathy is the most common running-associated tendinopathy followed by runner's knee and shin splints.
To examine hip abductor strength in long-distance runners with iliotibial band syndrome (ITBS), comparing their injured-limb strength to their nonaffected limb and to the limbs of a control group of healthy long-distance runners; and to determine whether correction of strength deficits in the hip abductors of the affected runners through a rehabilitation program correlates with a successful return to running.
Case series.
Stanford University Sports Medicine Clinics.
24 distance runners with ITBS (14 female, 10 male) were randomly selected from patients presenting to our Runners' Injury Clinic with history and physical examination findings typical for ITBS. The control group of 30 distance runners (14 females, 16 males) were randomly selected from the Stanford University Cross-Country and Track teams.
Group differences in hip abductor strength, as measured by torque generated, were analyzed using separate two-tailed t-tests between the injured limb, non-injured limb, and the noninjured limbs of the control group. Prerehabilitation hip abductor torque for the injured runners was then compared with postrehabilitation torque after a 6-week rehabilitation program.
Hip abductor torque was measured with the Nicholas Manual Muscle Tester (kg), and normalized for differences in height and weight among subjects to units of percent body weight times height (%BWh). Average prerehabilitation hip abductor torque of the injured females was 7.82%BWh versus 9.82%BWh for their noninjured limb and 10.19%BWh for the control group of female runners. Average prerehabilitation hip abductor torque of the injured males was 6.86%BWh versus 8.62%BWh for their noninjured limb and 9.73%BWh for the control group of male runners. All prerehabilitation group differences were statistically significant at the p < 0.05 level. The injured runners were then enrolled in a 6-week standardized rehabilitation protocol with special attention directed to strengthening the gluteus medius. After rehabilitation, the females demonstrated an average increase in hip abductor torque of 34.9% in the injured limb, and the males an average increase of 51.4%. After 6 weeks of rehabilitation, 22 of 24 athletes were pain free with all exercises and able to return to running, and at 6-months follow-up there were no reports of recurrence.
Long distance runners with ITBS have weaker hip abduction strength in the affected leg compared with their unaffected leg and unaffected long-distance runners. Additionally, symptom improvement with a successful return to the preinjury training program parallels improvement in hip abductor strength.
Context:Recent research has underpinned the occurrence of non-local exercise effects. For
instance, self-myofascial release (SMR) of the plantar fascia increases hamstring extensibility. A possible mechanism consists in a mechanical force transmission across myofascial chains. However, as the degree of structural continuity in these chains decreases with age, the magnitude of the above described remote effects might also be reduced throughout lifespan.
Objective: To examine the age-dependency of non-local exercise effects following plantar fascia SMR.
Design: Regression experimental study.
Setting: General population
Participants: 168 healthy participants (45±21 years, 85 males)
Intervention: One 120 s bout of plantar foot SMR, performed in standing position.
Main outcomes measure: Hamstring extensibility was assessed using sit and reach testing. Relative pre-post differences were classified as no improvement, clinically non-relevant improvement, or clinically relevant improvement according to previously published data. The age-dependency of the effects was calculated by means of multinomial stepwise logistic regression. If the latter revealed other factors than age to affect treatment effectivity, their effect was eliminated using partial correlation.
Results: SMR increased hamstring extensibility by 10.1% (pre: 24.9±9.7 cm, post: 27.4±9.3 cm, p<.0001). 99 participants (58.9 %) attained a clinically relevant change. Multinomial logistic regression demonstrated no influence of sex, amount of physical activity, height, BMI, and daytime, but a significant impact of baseline flexibility and age (Nagelkerke’s r²=.32, p<.001). Post hoc partial correlation analysis demonstrated that age, corrected for baseline flexibility, had a small to moderate association with treatment effectivity (r=.29, p<.0001).
Conclusions: Plantar foot SMR increases hamstring extensibility, which is explained by age to a small degree. Additional research is warranted in order to delineate the substrate of remote exercise effects. Besides mechanical force transmission, also cortical adaptations might represent the driving factor.
Recent research indicates that fascia is capable of changing its biomechanical properties. As it, moreover, links the skeletal muscles, forming a body-wide network of multidirectional myofascial continuity, the classical conception of muscles as independent actuators has been challenged. The present synthesis review hence aims to characterize the mechanical relevance of the connective tissue for the locomotor system. Results of cadaveric and animal studies suggest a clinically relevant myofascial force transmission to neighboring structures within one limb (e.g., between synergists) and in the course of muscle-fascia chains (e.g. between leg and trunk). Initial in vivo trials appear to underpin these findings, demonstrating the existence of non-local exercise effects. However, the factors influencing the amount of transmitted force (e.g., age and physical activity) remain controversial as well as the role of the central nervous system within the context of the observed remote exercise effects.
Lower limb stretching based on myofascial chains has been demonstrated to increase cervical range of motion (ROM) in the sagittal plane. It is, however, unknown whether such remote exercise is as effective as local stretching. To resolve this research deficit, 63 healthy subjects (36±13 years, ♂32) were randomly assigned to one of three groups: remote stretching of the lower limb (LLS), local stretching of the cervical spine (CSS), or inactive control (CON). Prior (M1), immediately post (M2) and 5 minutes following intervention (M3), maximal cervical ROM was assessed. Non-parametric data analysis (Kruskal-Wallis tests and adjusted post hoc Dunn tests) revealed signifi-cant differences between the disposed conditions. With one exception (cervical spine rotation after CSS at M2, p>.05), both LLS and CSS increased cervical ROM com-pared to the control group in all movement planes and at all measurements (p<.05). Between LLS and CSS, no statistical differences were found (p>.05). Lower limb stretching based on myofascial chains induces similar acute improvements in cervical ROM as local exercise. Therapists might consequently consider its use in program de-sign. However, as the attained effects do not seem to be direction-specific, further research is warranted in order to provide evidence-based recommendations.
Different authors have modelled myofascial tissue connectivity over a distance using cadaveric models, but in vivo models are scarce. The aim of this study was to evaluate the relationship between pelvic motion and deep fascia displacement in the medial gastrocnemius (MG). Deep fascia displacement of the MG was evaluated through automatic tracking with an ultrasound. Angular variation of the pelvis was determined by 2D kinematic analysis. The average maximum fascia displacement and pelvic motion were 1.501 ± 0.78 mm and 6.55 ± 2.47 °, respectively. The result of a simple linear regression between fascia displacement and pelvic motion for three task executions by 17 individuals was r = 0.791 (P < 0.001). Moreover, hamstring flexibility was related to a lower anterior tilt of the pelvis (r = 0.544, P < 0.024) and a lower deep fascia displacement of the MG (r = 0.449, P < 0.042). These results support the concept of myofascial tissue connectivity over a distance in an in vivo model, reinforce the functional concept of force transmission through synergistic muscle groups, and grant new perspectives for the role of fasciae in restricting movement in remote zones.
To provide evidence for the existence of six myofascial meridians proposed by Myers (1997) based on anatomical dissection studies.
Relevant articles published between 1900 and December 2014 were searched in MEDLINE (Pubmed), ScienceDirect and Google Scholar.
Peer-reviewed human anatomical dissection studies reporting morphological continuity between the muscular constituents of the examined meridians were included. If no study demonstrating a structural connection between two muscles was found, papers on general anatomy of the corresponding body region were targeted.
A continuity between two muscles was only documented if two independent investigators agreed that it was reported clearly. Also, two independent investigators rated methodological quality of included studies by means of a validated assessment tool (QUACS).
The literature search identified 6589 articles. Of these, 62 papers met the inclusion criteria. The studies reviewed suggest strong evidence for the existence of three myofascial meridians: the superficial back line (all three transitions verified, based on 14 studies), the back functional line (all three transitions verified, 8 studies) and the front functional line (both transitions verified, 6 studies). Moderate to strong evidence is available for parts of the spiral line (five of nine verified transitions, 21 studies) and the lateral line (two of five verified transitions, 10 studies). No evidence exists for the superficial front line (no verified transition, 7 studies).
The present systematic review suggests that most skeletal muscles of the human body are directly linked by connective tissue. Examining the functional relevance of these myofascial chains is the most urgent task of future research. Strain transmission along meridians would both open a new frontier for the understanding of referred pain and provide a rationale for the development of more holistic treatment approaches.
Copyright © 2015 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.
Introduction
Posterior and anterior oblique muscle slings contribute to the force closure mechanisms that provide stability to sacroiliac joint. These global muscle slings consist of myofascial network of fascia, muscles and tendons from global muscles. It links the lumbopelvic region to other joints of musculoskeletal system especially the contralateral glenohumeral joint (GHJ). Any sacroiliac joint dysfunction (SJD) may likely disrupt the force transmission across the oblique slings and it can affect the contralateral GHJ.
Aim
The current study aims to investigate the effects of SJD on the contralateral GHJ.
Material and methods
An experimental study is designed recruiting 20 participants with SJD and 20 healthy participants as matched controls to test the hypothesis that SJD may cause excessive anterior translation of humeral head (ATHH) in contralateral GHJ. Using real time ultrasonography, resting position of humeral head (RPHH), ATHH and posttranslation distance of humeral head (PDHH) are compared between the GHJs among participants with SJD and the matched controls. Paired sample t-test and independent sample t-test are used to analyze the data.
Results and discussion
The paired sample t-test result showed statistically significant increase in ATHH (P = 0.03) and PDHH (P = 0.01) in contralateral GHJs among participants with SJD. The independent sample t-test showed a significant increase in RPHH (P = 0.01) and PDHH (P = 0.01) in SJD participants when compared to matched controls.
Conclusion
SJD contributes to excessive ATHH in the contralateral GHJ. This may occur due to altered myofascial force transmission across oblique sling muscles.
Fascia is a highly organized collagenous tissue that is ubiquitous in the body, but whose function is not well understood. Because fascia has a sheet-like structure attaching to muscles and bones at multiple sites, it is exposed to different states of multi- or biaxial strain. In order to measure how biaxial strain affects fascia material behavior, planar biaxial tests with strain control were performed on longitudinal and transversely oriented samples of goat fascia lata (FL). Cruciform samples were cycled to multiple strain levels while the perpendicular direction was held at a constant strain. Structural differences among FL layers were examined using histology and SEM. Results show that FL stiffness, hysteresis, and strain energy density are greater in the longitudinal vs. transverse direction. Increased stiffness in the longitudinal layer is likely due to its greater thickness and greater average fibril diameter compared to the transverse layer(s). Perpendicular strain did not affect FL material behavior. Differential loading in the longitudinal vs. transverse directions may lead to structural changes, enhancing the ability of the longitudinal FL to transmit force, store energy, or stabilize the limb during locomotion. The relative compliance of the transverse fibers may allow expansion of underlying muscles when they contract.
There is not full agreement regarding the distal insertions of the gluteus maximus muscle (GM), particularly the insertions into the iliotibial band and lateral intermuscular septum. 6 cadavers, 4 males and 2 females, mean age 69 yr, were dissected to evaluate the insertions of the GM into the iliotibial band, fascia lata, lateral intermuscular septum and femur. The iliotibial band is a reinforcement of the fascia lata and cannot be separated from it. Its inner side is in continuity with the lateral intermuscular septum, which divides the quadriceps from the hamstring. In all subjects the gluteus maximus presented a major insertion into the fascia lata, so large that the iliotibial tract could be considered a tendon of insertion of the gluteus maximus. The fascial insertion of the gluteus maximus muscle could explain the transmission of the forces from the thoracolumbar fascia to the knee.
This article focuses on the (functional) anatomy and biomechanics of the pelvic girdle and specifically the sacroiliac joints (SIJs). The SIJs are essential for effective load transfer between the spine and legs. The sacrum, pelvis and spine, and the connections to the arms, legs and head, are functionally interrelated through muscular, fascial and ligamentous interconnections. A historical overview is presented on pelvic and especially SIJ research, followed by a general functional anatomical overview of the pelvis. In specific sections, the development and maturation of the SIJ is discussed, and a description of the bony anatomy and sexual morphism of the pelvis and SIJ is debated. The literature on the SIJ ligaments and innervation is discussed, followed by a section on the pathology of the SIJ. Pelvic movement studies are investigated and biomechanical models for SIJ stability analyzed, including examples of insufficient versus excessive sacroiliac force closure.
This study examined a potential cellular basis for strain hardening of fascial tissues: an increase in stiffness induced by stretch and subsequent rest. Mice lumbodorsal fascia were isometrically stretched for 15 min followed by 30 min rest (n=16). An increase in stiffness was observed in the majority of samples, including the nonviable control samples. Investigations with porcine lumbar fascia explored hydration changes as an explanation (n=24). Subject to similar loading procedures, tissues showed decreases in fluid content immediately post-stretch and increases during rest phases. When allowed sufficient resting time, a super-compensation phenomenon was observed, characterised by matrix hydration higher than initial levels and increases in tissue stiffness. Therefore, fascial strain hardening does not seem to rely on cellular contraction, but rather on this super-compensation. Given a comparable occurrence of this behaviour in vivo, clinical application of routines for injury prevention merit exploration.
The architecture of the connective tissue, including structures such as fasciae, sheaths, and membranes, is more important for understanding functional meaning than is more traditional anatomy, whose anatomical dissection method neglects and denies the continuity of the connective tissue as integrating matrix of the body.
The connective tissue anatomy and architecture exhibits two functional tendencies that are present in all areas of the body in different ways and relationships. In body cavities, the “disconnecting” quality of shaping space enables mobility; between organs and body parts, the “connecting” dimension enables functional mechanical interactions. In the musculoskeletal system, those two features of the connective tissue are also present. They cannot be found by the usual analytic dissection procedures. An architectural description is necessary.
This article uses such a methodologic approach and gives such a description for the lateral elbow region. The result is an alternative architectural view of the anatomic substrate involved in the transmission and conveyance of forces over synovial joints. An architectural description of the muscular and connective tissue organized in series with each other to enable the transmission of forces over these dynamic entities is more appropriate than is the classical concept of “passive” force-guiding structures such as ligaments organized in parallel to actively force-transmitting structures such as muscles with tendons.
The discrimination between so-called joint receptors and muscle receptors is an artificial distinction when function is considered. Mechanoreceptors, also the so-called muscle receptors, are arranged in the context of force circumstances—that is, of the architecture of muscle and connective tissue rather than of the classical anatomic structures such as muscle, capsules, and ligaments. In the lateral cubital region of the rat, a spectrum of mechanosensitive substrate occurs at the transitional areas between regular dense connective tissue layers and the muscle fascicles organized in series with them. This substrate exhibits features of type and location of the mechanosensitive nerve terminals that usually are considered characteristic for “joint receptors” as well as for “muscle receptors.”
The receptors for proprioception are concentrated in those areas where tensile stresses are conveyed over the elbow joint. Structures cannot be divided into either joint receptors or muscle receptors when muscular and collagenous connective tissue structures function in series to maintain joint integrity and stability. In vivo, those connective tissue structures are strained during movements of the skeletal parts, those movements in turn being induced and led by tension in muscular tissue. In principle, because of the architecture, receptors can also be stimulated by changes in muscle tension without skeletal movement, or by skeletal movement without change in muscle tension. A mutual relationship exists between structure (and function) of the mechanoreceptors and the architecture of the muscular and regular dense connective tissue. Both are instrumental in the coding of proprioceptive information to the central nervous system.
Cerebral palsy (CP) results from an upper motoneuron (UMN)lesion in the developing brain. Secondary to the UMNl esion,which causes spasticity, is a pathological response by muscle - namely, contracture. However, the elements within muscle that increase passive mechanical stiffness, and therefore result in contracture, are unknown. Using hamstring muscle biopsies from pediatric patients with CP (n =33) and control (n =19) patients we investigated passive mechanical properties at the protein, cellular, tissue and architectural levels to identify the elements responsible for contracture. Titin isoform, the major load-bearing protein within muscle cells, was unaltered in CP. Correspondingly, the passive mechanics of individual muscle fibres were not altered. However, CP muscle bundles, which include fibres in their constituent ECM, were stiffer than control bundles. This corresponded to an increase in collagen content of CP muscles measured by hydroxyproline assay and observed using immunohistochemistry. In vivo sarcomere length of CP muscle measured during surgery was significantly longer than that predicted for control muscle. The combination of increased tissue stiffness and increased sarcomere length interact to increase stiffness greatly of the contracture tissue in vivo. These findings provide evidence that contracture formation is not the result of stiffening at the cellular level, but stiffening of the ECM with increased collagen and an increase of in vivo sarcomere length leading to higher passive stresses.
Current evidence suggests that limited ankle dorsiflexion is an etiologic factor for plantar fasciitis. This limitation can arise from either an isolated contracture of the gastrocnemius or from a contracture of the gastrocnemius-soleus complex. This study's aim was to determine the proportion of patients with plantar fasciitis that have an associated isolated gastrocnemius contracture.
This investigation was a prospective evaluation of patients with either acute or chronic plantar fasciitis. Two hundred fifty-four patients with plantar fasciitis were included. Patients were assessed for the existence of limited ankle dorsiflexion which was further characterized by noting the presence of an isolated gastrocnemius contracture or contracture of the gastrocnemius-soleus complex. The patient's duration of symptoms, type of occupation, and body mass index were also documented. Patients with acute plantar fasciitis were defined as having symptom duration of 9 months or less while those with chronic plantar fasciitis were those with over 9 months of symptoms. The Wilcoxon rank sum and chi square tests were used to compare characteristics between the acute and chronic populations.
Eighty-three percent (211 of 254 patients) had limited ankle dorsiflexion. Fifty-seven percent (145 of 254) had an isolated contracture of the gastrocnemius, 26% (66 of 254) had a contracture of the gastrocnemius-soleus complex, and 17% (43 of 254) did not have a dorsiflexion limitation. Patients were further stratified into acute versus chronic symptom duration at the time of presentation. Equinus contracture was noted in 83% (129 of 155) of acute cases, and 82% (82 of 99) of chronic cases. An isolated contracture of the gastrocnemius was found in 60% (93 of 155) of acute, and 52% (52 of 99) of chronic cases. A gastrocnemius-soleus complex contracture was noted in 23% (36 of 155) of acute cases, and 30% (30 of 99) of chronic cases. Patients with chronic plantar fasciitis had a significantly higher number (p<0.05) of medical comorbidities than those with acute plantar fasciitis.
Limited ankle dorsiflexion is commonly associated with plantar fasciitis and more than half of these patients had evidence of an isolated gastrocnemius contracture. These findings can be utilized to develop and further refine non-operative and operative treatment strategies for those with recalcitrant plantar fasciitis.
YUCESOY, C.A. Epimuscular myofascial force transmission implies novel principles for muscular mechanics. Exerc. Sport Sci. Rev., Vol. 38, No. 3, pp. 128-134, 2010. In addition to the myotendinous junctions, muscle fibers also are connected to the extracellular matrix along their full peripheral length. Moreover, within the in vivo context, muscle is not an isolated entity. Instead, myofascial tissues connect muscles mechanically to neighboring muscular and nonmuscular structures, epimuscularly. This paper reviews the key aspects, determinants, and effects of epimuscular myofascial force transmission on muscular mechanics.
Overuse injuries may represent as much of a problem as do acute injuries in many sports. This paper reviews key concepts related to the methodology for recording overuse symptoms. Results from the FIVB Volleyball Injury Study were used to compare two different recording methods. The aim of this paper was to provide recommendations on how standardised methodology can be developed to quantify overuse injuries in surveillance studies. Using beach volleyball data, a "traditional" cohort study approach using a time-loss injury definition suggested that injury risk was very low. In contrast, the data from a survey of past and present pain problems in the shoulder, knees and low back demonstrated that these were prevalent. The following recommendations are made: (1) studies should be prospective, with continuous or serial measurements of symptoms; (2) valid and sensitive scoring instruments need to be developed to measure pain and other relevant symptoms; (3) prevalence and not incidence should be used to report injury risk; (4) severity should be measured based on functional level and not time loss from sports. In conclusion, new approaches are needed to develop more appropriate methodology to quantify overuse injuries in studies.
To examine the relationship between hamstring extensibility by use of the instrumented straight leg raise; mechanical components of muscle contraction, including muscle recruitment, passive torque measures of tissue stiffness, and eccentric strength; and self-reported measures of pain and disability.
Cross-sectional study.
University laboratory.
Twenty-one individuals with chronic nonspecific axial lower back pain and 15 healthy control subjects.
Instrumented straight leg raise, concentric and eccentric hamstring strength, self-reported measures of pain, disability, fear avoidance, general health and well-being
Objective measures included hamstring extensibility, hamstring muscle stiffness, absolute and relative concentric/eccentric strength, concentric/eccentric strength ratios. Self-reported measures included Oswestry disability index, visual analog pain scale, fear avoidance beliefs, and general health and well being.
Patients with lower back pain had lower range of motion, greater changes in muscle stiffness, and impaired concentric-to-eccentric strength levels. Stepwise regression identified measures of stiffness as significantly predicting hamstring extensibility (adjusted r(2) = 0.58, F = 23.76, P < .001). Self-reported measures were not associated with extensibility. Gender differences were noted for passive stiffness and absolute strength. For women, later onset of the medial hamstrings also was associated with greater hamstring extensibility.
Decreased extensibility of the hamstrings was associated with increased passive stiffness during the common range of motion (20 to 50 degrees ). Impaired stretch tolerance is associated with actual mechanical restriction, not behavioral measures indicating increased pain or fear-avoidant behavior. With no relationship to actual disability and contradictory findings in the literature for the relationship of the hamstrings to the mechanics of the low back, it is unclear whether decreased hamstring extensibility should be targeted in rehabilitation programs for axial lower back pain.
Biochemical changes occur in the constituents of periarticular connective tissues of the knee of rabbits with contractures resulting from a 9 wk period of immobility. The changes consisted of a marked reduction in concentration of water, hyaluronic acid, chondroitin 4 and 6 sulfate but an insignificant decrease in dermatan sulfate. There was no significant change in the total collagen content expressed either on the basis of concentration or on the basis of total periarticular connective tissue. Morphologic changes were similar to those previously described, except that adhesions and pannus were less prominent. The immobilized rabbit knee will be a useful model for further studies on joint contracture where biochemical biomechanical correlates are required to monitor drug and hormone effects on the contracture process.
The superficial and deep lamina of the posterior layer of the thoracolumbar fascia have been studied anatomically and biomechanically. In embalmed human specimens, the posterior layer has been loaded by simulating the action of various muscles. The effect has been studied using raster photography.
To study the role of the posterior layer of the thoracolumbar fascia in load transfer between spine, pelvis, legs, and arms.
It has been determined whether muscles such as the gluteus maximus, latissimus dorsi, erector muscle, and biceps femoris are functionally coupled via the thoracolumbar fascia. The caudal relations of the posterior layer of the thoracolumbar fascia have not been previously studied.
Dissection was directed to the bilaminar posterior layer of the thoracolumbar fascia of 10 human specimens. The superficial and deep lamina were studied using visual inspection and raster photography. Tension to the posterior layer of the fascia was simulated by traction to various muscles and measured by studying the displacement in the posterior layer.
Traction to a variety of muscles caused displacement of the posterior layer. This implies that in vivo, the superficial lamina will be tensed by contraction of various muscles, such as the latissimus dorsi, gluteus maximus and erector muscle, and the deep lamina by contraction of the biceps femoris. Caudal to the level of L4 (in some specimens, L2-L3), tension in the posterior layer was transmitted to the contralateral side.
Anatomic structures normally described as hip, pelvic, and leg muscles interact with so-called arm and spinal muscles via the thoracolumbar fascia. This allows for effective load transfer between spine, pelvis, legs, and arms--an integrated system. Specific electromyographic studies should reveal whether the gluteus maximus muscle and contralateral latissimus dorsi muscle are functionally coupled, especially during rotation of the trunk. In that case, the combined action of these muscles assists in rotating the trunk, while simultaneously stabilizing the lower lumbar spine and sacroiliac joints.
The actual path of force transmission in skeletal muscle from actomyosin interaction to tension at the tendinous insertion site is poorly understood. Within the muscle cell, endo- and exosarcomeric cytoskeletal proteins create series and parallel connections between contractile proteins resulting in a meshwork across which force can be transmitted in practically any direction with respect to the fiber axis. At the surface membrane, connections between the intermediate filament system, dystrophin, and specialized membrane complexes provide the route of force transmission to the extracellular matrix material. Finally, parallel and series connections between muscle fibers allow radial and longitudinal forces to converge on the connective tissue matrix. This complex pathway will certainly be the subject of future studies in muscle biology, biomechanics, and physiology.
Groin pain in athletes is one of the most difficult to treat clinical entities in sports medicine. The reasons are the amount of differential diagnoses, complexity of pathophysiologic causes and the long time of limited participation in sport. In order to maximize efficient treatment, thorough diagnostics and a clear therapeutic regimen are crucial. To succeed with this issue, a close cooperation between physicians and radiologists is mandatory. MRI is gold standard in the diagnostic work-up of the principal differential diagnoses, such as muscle tears, avulsion injuries, stress fractures, tears of acetabular labrum, and osteitis pubis. The article gives a comprehensive overview of the special anatomy and biomechanics of the pubic region and of typical MRI findings in athletes with groin pain. The use of dedicated imaging protocols is also discussed.Key Points:Citation Format:
It has been suggested that superior decentralization of the humeral head is a mechanical factor in the etiology of degenerative rotator cuff tears. This superior decentralization may be caused by muscular imbalance. The objective of this study was to investigate the contribution of individual shoulder muscles to superior stability of the glenohumeral joint. In 10 fresh frozen cadaver shoulders the tendons of the rotator cuff, teres major, latissimus, pectoralis major, deltoid and biceps were prepared. The shoulders were tested in a shoulder-loading device in 0 degrees, 30degrees, 60 degrees and 90 degrees of glenohumeral abduction. A constant superior force of 20 N was applied to the humerus. Tensile loads were applied sequentially to the tendons in proportion to their cross-sectional areas and translations of the humeral head relative to the glenoid were recorded with a 3Space Fastrak system. Depression of the humeral head was most effectively achieved by the latissimus (5.6 +/- 2.2 mm) and the teres major (5.1 +/- 2.0 mm). Further studies should elucidate their possible in vivo role in the frontal plane force couple to counter balance the deltoid. The infraspinatus (4.6 +/- 2.0 mm) and subscapularis (4.7 +/- 1.9 mm) showed similar effects while the supraspinatus (2.0 +/- 1.4 mm) was less effective in depression. Therefore, the infraspinatus and subscapularis should be surgically repaired whenever possible. The supraspinatus may be of less importance for superior stability than previously assumed.
The purpose of this study was to measure and compare the passive elastic moment, the stiffness and the damping coefficient of the hip joint, as functions of the hip and knee joint angles in men with and without low-back pain. Two conventional tests, the straight-leg-raising test and the trunk forward flexion, were also performed and compared between these subjects. The passive elastic moment was measured using an isokinetic device in the passive mode. This device raised the lower limb from the horizontal position to the straight-leg-raising angle at a slow and constant angular velocity. A custom-made splint connected with the lever arm of the isokinetic device maintained the knee in extension and the ankle in the neutral position. The damping coefficient of the hip joint was measured for 0, 15, 45, 60, 75 and 90% of straight leg raising angle of each subject, using the suspension method based on small oscillation theory. To ensure that muscles were inactive during the passive hip moment tests, muscle activity was monitored with surface EMG. The stiffness was computed as the ratio of the change in passive elastic moment to the change in the hip angle. The passive elastic moment, the stiffness and the normalized trunk flexion were significantly different between the two groups respectively. There was, however, no difference between the two groups in the results of straight-leg-raise and damping coefficient of the hip. The passive elastic moment was a nonlinear function of the hip flexion angle and showed large intersubject differences, especially as the joint limit was approached. The damping coefficient was a polynomial function of the hip flexion angle. The measured variables were analysed using a discriminant function and it was shown that the two groups were clearly discriminable in a meaningful manner.
Two-group mixed-model analysis of covariance and correlation analysis.
To determine whether differences in humeral translations exist between patients with shoulder impingement symptoms and an asymptomatic comparison group, and if so, to determine if shoulder range-of-motion (ROM) measures are associated with abnormal translations.
Abnormal translations of the humeral head are believed to reduce the available subacromial space and to contribute to the development or progression of shoulder impingement symptoms. These abnormal translations have also been theorized to be related to tightness of the posterior capsule and decreased shoulder ROM.
Three-dimensional humeral translations were tracked in symptomatic construction workers and an asymptomatic comparison group while elevating the arm in the scapular plane under no-load, 2.3-kg, and 4.6-kg hand-load conditions. Between-group comparisons were made across 3 phases of motion (30 degrees-60 degrees, 60 degrees-90 degrees, and 90 degrees-120 degrees) and the association between humeral translations and cross-body adduction and shoulder internal rotation ROM measures were determined by Pearson correlation analysis.
Persons with shoulder symptoms demonstrated small but significant changes in anterior-posterior translations of the humerus. These changes for the 90 degrees-120 degrees phase of humeral elevation were moderately negatively associated with available cross-body adduction ROM.
The identified kinematic deviations are consistent with possible reductions of the subacromial space. Further study of relationships between posterior capsule tightness, rotator cuff function, and abnormal humeral translations is warranted to better delineate underlying kinematic mechanisms that may contribute to shoulder impingement symptoms and to refine rehabilitation techniques.
A two-group experimental design with repeated measures on one factor was used.
To describe the relation between movement of the hip and lumbar spine during active hip flexion in healthy young adults and children.
Many descriptions of hip movement and procedures for clinically assessing the range of hip joint flexion do not take into account the substantive range of lumbar spine motion that normally accompanies hip flexion. Posterior pelvic rotation, representative of lumbar flexion during hip flexion, has been incorrectly regarded as a compensatory movement.
Unilateral full range active hip (knee) flexion was examined using computer-aided video analysis in 22 healthy young adults and 22 healthy children.
Except for the first 3 degrees to 5 degrees of the upward movement of hip flexion, hip and lumbar spine motion was concurrent in both phases of the test movement in children and adults. On the average, every 3 degrees of hip motion was accompanied by 1 degrees of lumbar motion. Throughout the upward movement, the relative contribution of hip movement decreased while that of the lumbar spine increased. During the downward movement, the hip returned nearly to its original starting position while the lumbar spine remained noticeably flexed.
There is a concurrent motion of the lumbar spine-pelvis and hip during normal hip flexion that is analogous with the well-known scapulohumeral rhythm accompanying elevation of the shoulder. Failure to measure or account for the contribution of the lumbar spine to hip flexion could overestimate the range of hip flexion by as much as 33.3%.
The amount of intramuscular connective tissue (IMCT) and its morphological distribution is highly variable between muscles of differing function. The functional roles of this component of muscle have been poorly understood, but a picture is gradually emerging of the central role this component has in growth, transmission of mechanical signals to muscle cells and co-ordination of forces between fibres within a muscle. The aim of this review is to highlight recent advances that begin to show the functional significance of some of the variability in IMCT. IMCT has a number of clearly defined roles. It patterns muscle development and innervation, and mechanically integrates the tissue. In developing muscles, proliferation and growth of muscle cells is stimulated and guided by cell-matrix interactions. Recent work has shown that the topography of collagen fibres is an important signal. The timing and rates of expression of connective tissue proteins also show differences between muscles. Discussion of mechanical roles for IMCT has traditionally been limited to the passive elastic response of muscle. However, it is now clear that IMCT provides a matrix to integrate the contractile function of the whole tissue. Mechanical forces are co-ordinated and passed between adjacent muscle cells via cell-matrix interactions and the endomysial connective tissue that links the cells together. An emerging concept is that division of a muscle into fascicles by the perimysial connective tissue is related to the need to accommodate shear strains as muscles change shape during contraction and extension.
Compared to young adults, older adults exhibit a slower walking speed, smaller step length, shorter swing phase time and decreased range of motion in their lower extremity joints. The underlying mechanisms causing these gait adaptations is not well understood, with various musculoskeletal parameters being put forth as contributing factors, including increased joint stiffness and decreased isometric muscle strength. The objective of this study was to identify the necessary compensatory mechanisms to overcome such musculoskeletal deficits and regain a normal walking pattern. Understanding these mechanisms has important implications for designing effective rehabilitation interventions for older adults that target specific muscle groups and properties (e.g., isometric strength versus joint stiffness) to improve gait performance. Muscle-actuated forward dynamics simulations of normal walking were analyzed to quantify compensatory mechanisms in the presence of muscle weakness in specific muscle groups and increased hip joint stiffness. Of particular importance were the compensatory mechanisms provided by the plantar flexors, which were shown to be able to compensate for many musculoskeletal deficits, including diminished muscle strength in the hip and knee flexors and extensors and increased hip joint stiffness. This importance was further highlighted when a normal walking pattern could not be achieved through compensatory action of other muscle groups when the uniarticular and biarticular plantar flexor strength was decreased as a group. Thus, rehabilitation or preventative exercise programs may consider focusing on increasing or maintaining plantar flexor strength, which appears critical to maintaining normal walking mechanics.
Plantar fasciitis is a musculoskeletal disorder primarily affecting the fascial enthesis. Although poorly understood, the development of plantar fasciitis is thought to have a mechanical origin. In particular, pes planus foot types and lower-limb biomechanics that result in a lowered medial longitudinal arch are thought to create excessive tensile strain within the fascia, producing microscopic tears and chronic inflammation. However, contrary to clinical doctrine, histological evidence does not support this concept, with inflammation rarely observed in chronic plantar fasciitis. Similarly, scientific support for the role of arch mechanics in the development of plantar fasciitis is equivocal, despite an abundance of anecdotal evidence indicating a causal link between arch function and heel pain. This may, in part, reflect the difficulty in measuring arch mechanics in vivo. However, it may also indicate that tensile failure is not a predominant feature in the pathomechanics of plantar fasciitis. Alternative mechanisms including 'stress-shielding', vascular and metabolic disturbances, the formation of free radicals, hyperthermia and genetic factors have also been linked to degenerative change in connective tissues. Further research is needed to ascertain the importance of such factors in the development of plantar fasciitis.