Acute Compartment Syndrome in a Football Player With Quadriceps Contusion and Successful Return to Sport: A Case Report.

CASE: This report describes the case of quadriceps contusion progressing to acute compartment syndrome (ACS) of the thigh. A 17-year-old football player presented the morning after a direct impact injury to the anterior thigh in intractable pain and pain with short arc motion. He was diagnosed with ACS and underwent successful fasciotomy, ultimately returning to play at 4 months. CONCLUSION: ACS is rare but potential catastrophic progression of quadriceps contusion. Accurate and timely diagnosis followed by appropriate rehabilitation is necessary for optimal outcomes.

Bilateral quadriceps tendon rupture: two injuries 6 years apart.

We present a case of a fit man in his 50s, with simultaneous bilateral quadriceps tendon repair of injuries sustained 6 years apart. Spontaneous closed ruptures of the quadriceps tendon are uncommon. Clinical data of a single case of bilateral quadriceps tendon injury with simultaneous repair was gathered via the patient, notes and surgeon. Diagnosis was primarily based on history and clinical examination. Suggestive features on the plain radiographic imaging were also present. Confirmation was attempted using ultrasonography but yielded conflicting reports. The patient was screened for any associated predisposing conditions that would preclude surgical intervention or increase risk of recurrence. Repairs were accomplished by employing a combination of suture anchors and transpatellar cerclage reinforcement. Apposition of the tendon to the superior patellar pole was successful although with decreased passive flexion on the neglected side (approximately 30°) compared with the acute (approximately 90°). Follow-up continues with postoperative rehabilitation.

Epidemiology of quadriceps muscle strain injuries in elite male Australian football players.

OBJECTIVE: To describe the epidemiology of quadriceps muscle strain injury (QMSI) in elite Australian Football League (AFL) players, explore recovery milestones and determine whether recovery is impacted by factors such as injury type (index vs. re-injury), the primary muscle injured and the mechanism of injury. MEASURES: All QMSI data reported to the Soft Tissue Injury Registry of the AFL from the 2014 to 2020 seasons were evaluated. Player demographic data, circumstances of injury, MRI reports and recovery outcomes following injury were extracted. Descriptive statistics and frequency distributions are presented. Recovery outcomes for injury type, primary muscle injured and the mechanism of injury were compared using univariate analyses. RESULTS: There were 164 QMSIs from 122 players reported (134 index; 30 re-injuries). Almost all (91.3%) QMSIs involved the rectus femoris. Half (48.4%) of the QMSIs occurred during kicking and most commonly affected the dominant kicking leg (72%). The majority occurred at training (64.6%). All re-injuries involved the rectus femoris, most occurred from kicking (63.0%) and within 6 months of the preceding injury (70%). The mean return to play (RTP) time was 25.4 days (95%CI = 22.6-28.2) and rectus femoris injuries took around 14 days longer to RTP than vastii injuries (p = 0.001). QMSIs with a kicking mechanism took the longest to RTP of all injury mechanisms. CONCLUSION: In AFL players, QMSIs occur mostly in the dominant leg from a kicking mechanism. Rectus femoris injuries are more prevalent and result in longer RTP time frames. Re-injuries exclusively involved the rectus femoris, primarily from kicking.

Lower Extremity Strains in the US National Football League, 2015-2019.

BACKGROUND: Lower extremity (LEX) strains, including hamstring, quadriceps, adductor, and calf strains, are among the most common injuries in sports. These injuries lead to high burden, resulting in significant missed participation time. PURPOSE: To describe the incidence of LEX strains in professional American football. STUDY DESIGN: Descriptive epidemiology study. METHODS: This study included all players who played in ≥1 National Football League (NFL) game or sustained a LEX strain during participation in the 2015-2019 seasons. LEX strain frequency was calculated by setting (game, practice, conditioning), timing in season (offseason, preseason, regular season, postseason), and roster position. Game incidence rates were calculated for season, roster position, and play type. LEX strains were identified in the standardized leaguewide electronic health record (n = 32 teams). RESULTS: Across 5 years, 5780 LEX strains were reported among 2769 players (1-year risk, 26.7%; 95% CI, 26.0%-27.3%); 69% (n = 4015) resulted in time loss. Among all LEX strains, 54.7% were hamstring (n = 3163), 24.1% adductor (n = 1393), 12.6% calf (n = 728), 8.3% quadriceps (n = 477), and 0.3% multiple muscle groups (n = 19). Most were reported during preseason practices (n = 1076; 27%) and regular season games (n = 1060; 26%). The 2-week period of training camp practices comprised 19% of all time-loss strains. Among game injuries, preseason games had the highest rate of LEX strain (2.9/10,000 player-plays; 95% CI, 2.6-3.2). Defensive secondary players accounted for the highest proportion of time-loss LEX strains (27%; n = 1082). In games, punt plays had nearly twice the injury rate of kickoff plays (14.9/1000 plays [95% CI, 13.1-17.0] vs 7.5/1000 plays [95% CI, 6.2-8.9], respectively) and >3 times the rate of pass plays (4.3/1000 plays; 95% CI, 4.0-4.7) and run plays (2.6/1000 plays; 95% CI, 2.3-2.9). In aggregate, LEX strains led to an estimated 16,748 participation days missed each year and a median 12 days missed per injury. CONCLUSION: LEX strains affected 1 in 4 NFL players each year, resulting in a high burden of injury in terms of time lost from practice and competition. Safe return to the NFL season during training camp and reduction of injuries during regular season games are key focuses for future injury reduction.

Rotura traumática simultánea y bilateral del tendón del cuádriceps en un paciente fisicoculturista: informe de caso y revisión de la literatura / Simultaneous bilateral traumatic quadriceps tendon rupture in a bodybuilding patient: case report and literature review

La rotura traumática, simultánea y bilateral del tendón cuadricipital es una lesión infrecuente, generalmente asociada a otras enfermedades sistémicas tales como insuficiencia renal o trastornos endocrinos. Presentamos el caso de un varón sano y atleta de 38 años que sufrió esta lesión mientras realizaba una sentadilla en el gimnasio. (AU)

The traumatic bilateral and simultaneous quadriceps tendon rupture is a rare injury, usually associated with other systemic diseases such as renal insufficiency or endocrine disorders. We present the case of a 38-year-old healthy male athlete who sustained this injury while performing a squat at the gym. (AU)

Indirect Rectus Femoris Injury Mechanisms in Professional Soccer Players: Video Analysis and Magnetic Resonance Imaging Findings.

OBJECTIVE: To describe injury mechanisms and magnetic resonance imaging (MRI) findings in acute rectus femoris (RF) injuries of soccer players using a systematic video analysis. DESIGN: Descriptive case series study of consecutive RF injuries from November 2017 to July 2022. SETTING: Two specialized sports medicine hospitals. PARTICIPANTS: Professional male soccer players aged between 18 and 40 years, referred for injury assessment within 7 days after a RF injury, with an available video footage of the injury and a positive finding on an MRI. INDEPENDENT VARIABLES: Rectus femoris injury mechanisms (specific scoring based on standardized models) in relation to RF muscle injury MRI findings. MAIN OUTCOME MEASURES: Rectus femoris injury mechanism (playing situation, player/opponent behavior, movement, and biomechanics), location of injury in MRI. RESULTS: Twenty videos of RF injuries in 19 professional male soccer players were analyzed. Three different injury mechanisms were seen: kicking (80%), sprinting (10%), and change of direction (10%). Isolated single-tendon injuries were found in 60% of the injuries. Of the kicking injuries, 62.5% included complete tendon ruptures, whereas both running injuries and none of the change of direction injuries were complete ruptures. The direct tendon was involved in 33% of the isolated injuries, and the common tendon was affected in all combined injuries. CONCLUSIONS: Rectus femoris injuries typically occur during kicking among football players. Most of the RF injuries involve a complete rupture of at least one tendon. Kicking injuries can also affect the supporting leg, and sprinting can cause a complete tendon rupture, whereas change of direction seems not to lead to complete ruptures.

Relationship between anatomical injury site of rectus femoris muscle strain and time taken to return to play in Japanese professional soccer players.

PURPOSE: The rectus femoris has three myotendinous or myoaponeurosis junctions and causes three types of muscle strain anatomically. We aimed to investigate the anatomical injury site of the rectus femoris muscle strain in professional soccer players as well as the characteristic findings on magnetic resonance imaging (MRI) and to evaluate its relationship with the time taken to return to play at competition levels. METHODS: Thirteen Japanese professional soccer players who sustained injuries to the rectus femoris were included in this study. The mechanism of injury, anatomical injury site, severity, absence of hematomas, and time taken to return to competition were evaluated. RESULTS: Ten patients were injured while kicking and three while sprinting. The anatomical injury site was the origin aponeurosis in two cases, intramuscular tendon in eight cases, and distal aponeurosis in three cases. The severity was one-degree in three cases and two-degree in 10 cases. Hematomas were observed in five cases. Cases with injuries caused by sprinting, two-degree injuries, or clear hematomas were associated with significantly longer periods of return to play than the other cases. Additionally, patients with distal aponeurosis-type injuries tended to take a long time to return to the competition. CONCLUSIONS: In rectus femoris muscle strain, it is important to evaluate the anatomical injury site, severity, and absence of hematomas on MRI. Not only the injury mechanism, a clear hematoma, and high severity but also distal aponeurosis injuries may be associated with long periods of return to play at competition levels.

Time to return to full training and recurrence of rectus femoris injuries in elite track and field athletes 2010-2019; a 9-year study using the British Athletics Muscle Injury Classification.

Rectus femoris (RF) injuries are common in sports requiring maximal acceleration and sprinting. The British Athletics Muscle Injury Classification (BAMIC) describes acute muscle injury based on the anatomical site of injury and has been associated with return to play in hamstring and calf muscle injury. The aim of this study was to describe and compare the time to return to full training (TRFT) and injury recurrence for BAMIC-classified RF injuries sustained by elite track and field (T&F) athletes over a 9-year period. All rectus femoris injuries sustained by elite T&F athletes on the British Athletics World Class Program between September 2010 and September 2019 that were investigated with an MRI within 7 days of acute onset anterior thigh pain were included. Injuries were graded from the MRI by a specialist musculoskeletal radiologist using the BAMIC, and TRFT and injury recurrence were determined by evaluation of the Electronic Medical Record. Athlete demographics and World Athletics event discipline were recorded. Specific injury details including mechanism, location of injury, and whether surgical or rehabilitation management was undertaken were recorded. There were 38 RF injuries in 27 athletes (24.7 ± 2.3 years; 10 male, 17 female). Average TRFT for rehabilitation managed cases was 20.4 ± 14.8 days. Grade 1 injuries had significantly shorter TRFT compared with grades 2 (p = 0.04) and 3 (p = 0.01). Intratendinous (c) and surgically managed RF injuries each had significantly longer TRFT compared with other injury classes (p < 0.001). Myofascial (a) injuries had reduced repeat injury rates compared with b or c classes (p = 0.048). Grade 3 injuries had an increased repeat injury rate compared with other grades (p = 0.02). There were 4 complete (4c) proximal free tendon injuries sustained during sprinting and all in female athletes. The average TRFT for RF injuries in elite T&F is similar to that previously identified in elite football and Australian Rules. Similar to previous research in hamstring and calf injury, RF injuries extending into the tendon (BAMIC class c) had delayed TRFT which may reflect the longer duration required for tendon healing and adaptation. Grade 3 injuries had in increased repeat injury rate compared with grades 1 and 2. The BAMIC diagnostic framework may provide useful information for clinicians managing rectus femoris injuries in T&F.

Association Between Injury Mechanisms and Magnetic Resonance Imaging Findings in Rectus Femoris Injuries in 105 Professional Football Players.

OBJECTIVE: To describe the injury mechanism and its association with magnetic resonance imaging (MRI) injury findings in acute rectus femoris injuries. DESIGN: Combined retrospective and prospective descriptive injury study. Retrospective cohort from January 2010 to October 2013 and prospective cohort from October 2013 to January 2019. SETTING: Specialized sports medicine hospital. PARTICIPANTS: Male professional football players older than 18 years playing in a national football league, referred for injury assessment within 7 days after an acute rectus femoris injury, with a positive finding on MRI. INDEPENDENT VARIABLES: Rectus femoris muscle injury MRI findings in relation to injury mechanism in male football players. MAIN OUTCOME MEASURES: Rectus femoris injury mechanism (kicking, sprinting, and others), MRI injury location, and grade. RESULTS: There were 105 injuries in total, with 60 (57.1%) and 45 (42.8%) injuries from the retrospective and prospective cohorts, respectively. Kicking was the injury mechanism in 57 (54.3%) of all acute rectus femoris injuries, sprinting represented 32 (30.4%), and 16 (15.2%) were classified as others. There were 20 (19.05%) free tendon, 67 (63.8%) myotendinous junction and/or intramuscular tendon, and 18 (17.1%) peripheral myofascial located injuries. All free tendon injuries were related to kicking and graded as a complete tear of at least one of the tendons in 15/20 (75.0%) cases. CONCLUSIONS: Kicking seems to be an important mechanism related to complete ruptures and injuries occurring at the proximal free tendon. Sprinting was the other most common mechanism but was never associated with injury to the proximal free tendon.

Should proximal ruptures of the anterior rectus femoris muscle be treated surgically?

PURPOSE: No therapeutic consensus has been established about proximal ruptures of the rectus femoris muscle. The objective of this literature review is to determine a therapeutic course of action. METHODS: We conducted a literature review on the PubMed database using the following keywords (in French and English, respectively): "quadriceps/quadriceps", "droit antérieur/rectus femoris", "proximal/proximal", "chirurgie/surgical", "avulsion/avulsion". We collected 266 articles, 36 of them were selected, which were related to our topic: proximal rupture of the anterior rectus femoris. Patients with a proximal rupture of the rectus femoris, minor or major patient of traumatic origin were included in this study. Patients injured at another lesion level, or non-traumatic lesions of the proximal rectus femoris (tendinitis without ruptures, tumor or others) were excluded. For each patient, the indications, the type of treatment and the functional result were analyzed, with the time to recovery and the level of recovery from sports and professional activities (same sport/profession or not, same level or not) as the main criterion of judgment. Fisher exact test was used for statistical comparison. RESULTS: The aims of conservative treatment are to be pain free for the patient, to fight hematoma and to rehabilitate the injury as quickly as possible. The surgical techniques are varied, with most consisting of either a reinsertion of the musculo-tendon stump or a resection of the scar tissue with myo-tendino-aponeurotic suture in place. The functional results are good for the majority of the treatments proposed, but the conservative treatment has a shorter recovery time (3 months vs. 4 months for the best surgical results). Highly displaced bone avulsion is the only indication for first-line surgical treatment. CONSLUSION: The main disadvantage of conservative treatment is the risk of residual pain beyond 3 months (10%), justifying an MRI to guide secondary surgical treatment. We propose a treatment plan for proximal rupture of the proximal rectus femoris rupture.

Pseudoaneurisma e fístula arteriovenosa da artéria femoral profunda após rotura completa do músculo vasto medial: tratamento endovascular / Pseudoaneurysm and arteriovenous fistula of the deep femoral artery after complete rupture of the vastus medialis muscle: endovascular treatment

Resumo A artéria femoral profunda, devido às suas características anatômicas, se encontra protegida da maioria dos traumatismos vasculares. Relatamos um caso de pseudoaneurisma de ramo perfurante da artéria femoral profunda, associado à fístula arteriovenosa, secundário a rotura completa do músculo vasto medial em paciente jogador de futebol. A ressonância magnética demonstrou lesão muscular associada a pseudoaneurisma, e a angiotomografia confirmou a presença de pseudoaneurisma associado a fístula arteriovenosa de ramo da artéria femoral profunda. Foi realizado tratamento endovascular da fístula através da embolização com micromolas fibradas e drenagem cirúrgica do hematoma muscular. O paciente evoluiu bem, sem queixas clínicas no 30º dia de pós-operatório e também após 1 ano.

Abstract Due to its anatomical characteristics, the deep femoral artery is protected from most vascular injuries. We report a case of a soccer player with pseudoaneurysm of a perforating branch of the deep femoral artery, associated with an arteriovenous fistula and secondary to complete rupture of the vastus medialis muscle. Magnetic resonance imaging showed muscle damage associated with a pseudoaneurysm and angiotomography confirmed the presence of a pseudoaneurysm associated with a deep arteriovenous fistula of a branch of the deep femoral artery. Endovascular treatment of the fistula was performed by embolization with fibrous microcoils and surgical drainage of the muscle hematoma. The patient recovered well, was free from clinical complaints on the 30th postoperative day and also after 1 year.

[Proximal avulsion of the rectus femoris muscle]. / Proximale Ausrisse des Musculus rectus femoris.

BACKGROUND: Injuries of the thigh muscles are among the most frequent sports injuries. For example, in soccer they represent nearly 30% of all injuries. The rectus femoris muscle is particularly exposed to injury due to its anatomical features. While distal ruptures involve the quadriceps tendon and are among the more frequent injuries not only in sports, proximal ruptures represent a rarity. Because of the mostly indifferent clinical signs, the diagnosis is often delayed. In the literature various versions of classifications on the grading of muscle injuries have been described. OBJECTIVE: With respect to the rectus femoris muscle, there is no classification system from which a treatment decision or an algorithm can be derived. The problem is not only the unclear classification of the injury but also the variability of treatment options resulting from this. MATERIAL AND METHODS: A selective search of the literature was carried out to construct a review article. RESULTS: No standardized follow-up treatment after surgical interventions or an established procedure for conservative treatment is currently available. CONCLUSION: The comparison of the individual studies is made difficult due to the low case numbers and nonuniform classification systems. A valid treatment algorithm can only be derived with difficulty based on the currently available data.

Differences in brain structure and theta burst stimulation-induced plasticity implicate the corticomotor system in loss of function after musculoskeletal injury.

Traumatic musculoskeletal injury (MSI) may involve changes in corticomotor structure and function, but direct evidence is needed. To determine the corticomotor basis of MSI, we examined interactions among skeletomotor function, corticospinal excitability, corticomotor structure (cortical thickness and white matter microstructure), and intermittent theta burst stimulation (iTBS)-induced plasticity. Nine women with unilateral anterior cruciate ligament rupture (ACL) 3.2 ± 1.1 yr prior to the study and 11 matched controls (CON) completed an MRI session followed by an offline plasticity-probing protocol using a randomized, sham-controlled, double-blind, cross-over study design. iTBS was applied to the injured (ACL) or nondominant (CON) motor cortex leg representation (M1LEG) with plasticity assessed based on changes in skeletomotor function and corticospinal excitability compared with sham iTBS. The results showed persistent loss of function in the injured quadriceps, compensatory adaptations in the uninjured quadriceps and both hamstrings, and injury-specific increases in corticospinal excitability. Injury was associated with lateralized reductions in paracentral lobule thickness, greater centrality of nonleg corticomotor regions, and increased primary somatosensory cortex leg area inefficiency and eccentricity. Individual responses to iTBS were consistent with the principles of homeostatic metaplasticity; corresponded to injury-related differences in skeletomotor function, corticospinal excitability, and corticomotor structure; and suggested that corticomotor adaptations involve both hemispheres. Moreover, iTBS normalized skeletomotor function and corticospinal excitability in ACL. The results of this investigation directly confirm corticomotor involvement in chronic loss of function after traumatic MSI, emphasize the sensitivity of the corticomotor system to skeletomotor events and behaviors, and raise the possibility that brain-targeted therapies could improve recovery.NEW & NOTEWORTHY Traumatic musculoskeletal injuries may involve adaptive changes in the brain that contribute to loss of function. Our combination of neuroimaging and theta burst transcranial magnetic stimulation (iTBS) revealed distinct patterns of iTBS-induced plasticity that normalized differences in muscle and brain function evident years after unilateral knee ligament rupture. Individual responses to iTBS corresponded to injury-specific differences in brain structure and physiological activity, depended on skeletomotor deficit severity, and suggested that corticomotor adaptations involve both hemispheres.

In Vivo Visualization of Tissue Damage Induced by Percutaneous Muscle Biopsy via Novel High-Resolution MR Imaging.

PURPOSE: Percutaneous muscle biopsy is the gold standard for tissue assessment in clinical practice and scientific studies. The aim of this study was to assess and quantify the ensuing tissue damage by in vivo magnetic resonance imaging (MRI). METHODS: In this prospective study, we enrolled 22 healthy participants who underwent MRI of the thigh musculature about 1 wk after a percutaneous muscle biopsy of the vastus lateralis muscle. A total of 17 participants also volunteered for a second MR examination 2 wk after biopsy. Volumes of susceptibility-weighted imaging (SWI) lesions and muscle edema were assessed by SWI and T2-weighted MRI, respectively, after manual segmentation by two independent readers. For quantitative in vivo hematoma volume assessment, we additionally determined signal changes induced by experimental hematoma in an ex vivo model. RESULTS: Mean overall volume of SWI lesions 1 wk after biopsy was 26.5 ± 21.7 µL, accompanied by a mean perifocal edema volume of 790.1 ± 591.4 µL. In participants who underwent two examinations, mean volume of SWI lesions slightly decreased from 29.8 ± 23.6 to 23.9 ± 16.8 µL within 1 wk (P = 0.13). Muscle edema volume decreased from 820.2 ± 632.4 to 359.6 ± 207.3 µL at the same time (P = 0.006). By calibration with the ex vivo findings, signal alterations on SWI corresponded to a blood volume of approximately 10-50 µL. CONCLUSIONS: Intramuscular hematoma and accompanying muscle edema after percutaneous biopsy are small and decrease rapidly within the first 2 wk. These in vivo findings underline the limited invasiveness of the procedure.

Modulating local S1P receptor signaling as a regenerative immunotherapy after volumetric muscle loss injury.

Regeneration of skeletal muscle after volumetric injury is thought to be impaired by a dysregulated immune microenvironment that hinders endogenous repair mechanisms. Such defects result in fatty infiltration, tissue scarring, chronic inflammation, and debilitating functional deficits. Here, we evaluated the key cellular processes driving dysregulation in the injury niche through localized modulation of sphingosine-1-phosphate (S1P) receptor signaling. We employ dimensionality reduction and pseudotime analysis on single cell cytometry data to reveal heterogeneous immune cell subsets infiltrating preclinical muscle defects due to S1P receptor inhibition. We show that global knockout of S1P receptor 3 (S1PR3) is marked by an increase of muscle stem cells within injured tissue, a reduction in classically activated relative to alternatively activated macrophages, and increased bridging of regenerating myofibers across the defect. We found that local S1PR3 antagonism via nanofiber delivery of VPC01091 replicated key features of pseudotime immune cell recruitment dynamics and enhanced regeneration characteristic of global S1PR3 knockout. Our results indicate that local S1P receptor modulation may provide an effective immunotherapy for promoting a proreparative environment leading to improved regeneration following muscle injury.

The influence of a soccer season on non-contact injury and isokinetic peak torque of the quadriceps and hamstrings in professional youth soccer players.

Isokinetic strength screening is utilized in professional soccer. However, there has been little research on the interaction between seasonal changes in players' peak torque (PT) and injury incidence. Twenty-five (age 16.5±0.68 years) professional youth soccer players participated in the study. Bilateral isokinetic concentric (CON) and eccentric (ECC) testing of Quadriceps (Q) and Hamstrings (H) were conducted at three time-points across the season. Absolute CON and ECC PT were measured at 60 degree/sec and in a supine 170-degree position. Testing data was normalized to body mass. A mixed design (2 by 3) repeated measures ANOVA with injury as a co-variate was conducted to evaluate the effect of season and/or limb dominance on PT and injury incidence. With regard to the seasonal variation and injury incidence, an interaction was identified with respect to non-dominant limb (NDL) QCON (p = 0.01) and to a lesser extent the dominant limb (DL) QCON (p = 0.05). The seasonal variation of the PT of the NDL QCON was different between the injured and non-injured individuals. Non-injured individuals, QCON strength increased over the course of the season. While for the Injured players, QCON declined from pre-season to mid-season then increased but never recovered to starting pre-season values.

Clinical and Anatomical Considerations for Management of a Complete Tear of the Distal Rectus Femoris Myotendinous Junction: A Rare Knee Extensor Mechanism Injury.

ABSTRACT: The knee extensor mechanism is a highly complex multilayered and reinforced structure. Quadriceps muscle injuries are considered to be common, particularly among athletes; however isolated rectus femoris injuries involving the distal myotendinous junction are considered to be exceedingly rare with very few case reports published to date. Thus, the presentation and diagnosis of this injury can be elusive and treatment is nonuniform. There is limited literature published advocating both nonsurgical and surgical management. We illustrate the clinical and radiologic presentation of a traumatic, nonsport-related distal rectus femoris muscle injury treated operatively. The presentation of this injury along with anatomical and clinical considerations is portrayed in detail. This case report contributes to the sparse literature regarding this injury and delineates management considerations.

Muscle length influence on rectus femoris damage and protective effect in knee extensor eccentric exercise.

This study tested the hypothesis that the magnitude of rectus femoris (RF) damage and the repeated bout effect (RBE) would be greater after knee extensor eccentric exercise performed in a supine (long RF lengths) than a sitting (short RF lengths) position, and the muscle length effects would be more prominent at the proximal than distal RF. Young untrained men were placed to one of the two groups (n = 14 per group). S group performed the knee extensor eccentric exercise in the sitting position for the first bout and the supine position for the second bout, and L group performed the exercise in the supine position for two bouts, with 4 weeks between bouts. Dependent variables included evoked and maximal voluntary isometric contraction (MVC) torque, electromyography (EMG) during MVC, muscle soreness, and shear modulus, which were measured before and 1-3 days after each exercise bout. After the first bout, L group in comparison with S group showed greater (P < .05) changes in hip flexor MVC torque (average of 1-3 days post-exercise: -11.1 ± 9.4% vs -5.0 ± 7.5%), proximal RF EMG (-22.4 ± 16% vs -9.0 ± 21.9%), and proximal RF shear modulus (33.2 ± 22.8% vs 16.9 ± 13.5%). No significant differences between groups were evident for any of other variables after the first bout including knee extensor MVC torque, and for the changes in all variables after the second bout. These results supported the hypothesis that RF damage would be greater for the spine than sitting position especially at the proximal region, but did not support the hypothesis about the RBE.

Lack of Abdominal Stability and Control as a Possible Contributor to Rectus Femoris Avulsion Fracture in the Adolescent Soccer Player: A Case Report.

PURPOSE: To describe evaluation and physical therapy treatment for an athlete who is male and 13 years old with healing bilateral rectus femoris avulsion fractures. SUMMARY OF KEY POINTS: Fractures of the anterior inferior iliac spine may be linked to poor abdominal stability in soccer athletes who are male and an adolescent. The development and use of an abdominal stability screening tool could be an efficient and effective way to determine fracture risk and guide prevention programs. CONCLUSIONS AND RECOMMENDATIONS FOR CLINICAL PRACTICE: Following 8 weeks of conservative physical therapy treatment, the athlete met all goals and returned to pain-free soccer activities without residual impairments. Four months following discharge, he reported full participation in soccer competition without complications. This case illustrates that abdominal weakness is a potential risk factor for anterior inferior iliac spine avulsion fracture. Screening for abdominal weakness and incorporating preventative programs into training regimens is recommended to prevent anterior inferior iliac spine injuries in this population.