Biceps femoris long head muscle and aponeurosis geometry in males with and without a history of hamstring strain injury.

OBJECTIVES: Hamstring strain injuries (HSIs) commonly affect the proximal biceps femoris long head (BFlh) musculotendinous junction. Biomechanical modeling suggests narrow proximal BFlh aponeuroses and large muscle-to-aponeurosis width ratios increase localized tissue strains and presumably risk of HSI. This study aimed to determine if BFlh muscle and proximal aponeurosis geometry differed between limbs with and without a history of HSI. METHODS: Twenty-six recreationally active males with (n = 13) and without (n = 13) a history of unilateral HSI in the last 24 months underwent magnetic resonance imaging of both thighs. BFlh muscle and proximal aponeurosis cross-sectional areas, length, volume, and interface area between muscle and aponeurosis were extracted. Previously injured limbs were compared to uninjured contralateral and control limbs for discrete variables and ratios, and along the relative length of tissues using statistical parametric mapping. RESULTS: Previously injured limbs displayed significantly smaller muscle-to-aponeurosis volume ratios (p = 0.029, Wilcoxon effect size (ES) = 0.43) and larger proximal BFlh aponeurosis volumes (p = 0.019, ES = 0.46) than control limbs with no history of HSI. No significant differences were found between previously injured and uninjured contralateral limbs for any outcome measure (p = 0.216-1.000, ES = 0.01-0.36). CONCLUSIONS: Aponeurosis geometry differed between limbs with and without a history of HSI. The significantly larger BFlh proximal aponeuroses and smaller muscle-to-aponeurosis volume ratios in previously injured limbs could alter the strain experienced in muscle adjacent to the musculotendinous junction during active lengthening. Future research is required to determine if geometric differences influence the risk of re-injury and whether they can be altered via targeted training.

Multiprotein collagen/keratin hydrogel promoted myogenesis and angiogenesis of injured skeletal muscles in a mouse model.

Volumetric loss is one of the challenging issues in muscle tissue structure that causes functio laesa. Tissue engineering of muscle tissue using suitable hydrogels is an alternative to restoring the physiological properties of the injured area. Here, myogenic properties of type I collagen (0.5%) and keratin (0.5%) were investigated in a mouse model of biceps femoris injury. Using FTIR, gelation time, and rheological analysis, the physicochemical properties of the collagen (Col)/Keratin scaffold were analyzed. Mouse C2C12 myoblast-laden Col/Keratin hydrogels were injected into the injury site and histological examination plus western blotting were performed to measure myogenic potential after 15 days. FTIR indicated an appropriate interaction between keratin and collagen. The blend of Col/Keratin delayed gelation time when compared to the collagen alone group. Rheological analysis revealed decreased stiffening in blended Col/Keratin hydrogel which is favorable for the extrudability of the hydrogel. Transplantation of C2C12 myoblast-laden Col/Keratin hydrogel to injured muscle tissues led to the formation of newly generated myofibers compared to cell-free hydrogel and collagen groups (p < 0.05). In the C2C12 myoblast-laden Col/Keratin group, a low number of CD31+ cells with minimum inflammatory cells was evident. Western blotting indicated the promotion of MyoD in mice that received cell-laden Col/Keratin hydrogel compared to the other groups (p < 0.05). Despite the increase of the myosin cell-laden Col/Keratin hydrogel group, no significant differences were obtained related to other groups (p > 0.05). The blend of Col/Keratin loaded with myoblasts provides a suitable myogenic platform for the alleviation of injured muscle tissue.

Resistance Exercise Sessions Comprising Multijoint vs. Single-Joint Exercises Result in Similar Metabolic and Hormonal Responses, But Distinct Levels of Muscle Damage in Trained Men.

ABSTRACT: Barbosa, PH, Bueno de Camargo, JB, Jonas de Oliveira, J, Reis Barbosa, CG, Santos da Silva, A, Dos-Santos, JW, Verlengia, R, Barreira, J, Braz, TV, and Lopes, CR. Resistance exercise sessions comprising multijoint vs. single-joint exercises result in similar metabolic and hormonal responses, but distinct levels of muscle damage in trained men. J Strength Cond Res 38(5): 842-847, 2024-Resistance-type exercise (RE) elicits distinct acute metabolic and hormonal responses, which can be modulated by the manipulation of training variables. The purpose of this study was to compare the metabolic (blood lactate and estimated lactic anaerobic system energy expenditure) and hormonal (growth hormone [GH]) responses to RE sessions composed exclusively of multijoint (MULTI) or single-joint (SINGLE) exercises. Assessments of creatine kinase (CK) levels were also performed. In a crossover design, 10 recreationally resistance-trained men (age: 26.9 ± 3.0 years, total body mass: 83.2 ± 13.8 kg; height: 176 ± 7.0 cm; training experience: 5.5 ± 2.4 years) were randomly submitted to both protocols. Blood collections were made pre, 3 minutes after, and 36 hours after each experimental session. No significant difference between MULTI vs. SINGLE was observed for the rises in blood lactate (p = 0.057) and GH (p = 0.285) levels. For CK, a significant difference between the protocols was noted, in which MULTI resulted in significant rises after 3 minutes (p = 0.017) and 36 hours (p = 0.043) compared with SINGLE. In conclusion, the findings of this study suggest that resistance-trained individuals display similar metabolic and hormonal responses when performing MULTI and SINGLE exercise protocols. Also, RE sessions comprising MULTI exercises induce a higher magnitude of muscle damage, which may require a longer recovery period compared with SINGLE.

Changes in hamstring contractile properties during the competitive season in young football players.

Background: The study aimed to examine alterations and imbalances in hamstring muscle contractile properties among young football players throughout their competitive season, and to understand how these changes might contribute to the risk of muscle injuries. Hamstring injuries are particularly common in football, yet the underlying causes and effective prevention methods remain unclear. Methods: The research involved 74 young footballers who were assessed before the season (pre-test) and after 12 weeks of training (post-test). To evaluate changes in hamstring muscle contractile properties, specifically the left and right biceps femoris (BF) and semitendinosus (ST), tensiomyography (TMG) parameters were utilized. Results: In comparison to the BF muscle, significant differences in time delay (Td) between the left and right sides in the post-test (p = 0.0193), and maximal displacement (Dm) between the left and right sides at the pre-test (p = 0.0395). However, significant differences in Dm were observed only in the left ST muscle between the pre- and post-tests (p = 0.0081). Regarding lateral symmetry, BF registered measurements of 79.7 ± 13.43 (pre-test) and 77.4 ± 14.82 (post-test), whereas ST showed measurements of 87.0 ± 9.79 (pre-test) and 87.5 ± 9.60 (post-test). Conclusions: These assessments provided TMG reference data for hamstring muscles in young footballers, both before the season and after 12 weeks of in-season training. The observed changes in the contractile properties and decrease in lateral symmetry of the BF in both tests suggest an increased risk of injury.

Podocan promoting skeletal muscle post-injury regeneration by inhibiting TGF-ß signaling pathway.

Podocan, the fifth member of Small Leucine-Rich Proteoglycan (SLRP) family of extracellular matrix components, is poorly known in muscle development. Previous studies have shown that Podocan promotes C2C12 differentiation in mice. In this study, we elucidated the effect of Podocan on skeletal muscle post-injury regeneration and its underlying mechanism. Injection of Podocan protein promoted the process of mice skeletal muscle post-injury regeneration. This effect seemed to be from the acceleration of muscle satellite cell differentiation in vivo. Meanwhile, Podocan promoted myogenic differentiation in vitro by binding with TGF-ß1 to inhibit the activity of the TGF-ß signaling pathway. These results indicated that Podocan had the potential roles to enhance skeletal muscle post-injury regeneration. Its mechanism is likely the regulation of the expression of p-Smad2 and p-Smad4 related to the TGF-ß signaling pathway by interacting with TGF-ß1.

Anterior pelvic tilt increases hamstring strain and is a key factor to target for injury prevention and rehabilitation.

PURPOSE: Hamstring muscle strain injury is very common in sports involving high-speed running. Hamstring muscles originate from the ischial tuberosity and thus pelvic position may influence hamstring strain during different sports movements like sprinting, but this has only been evaluated by indirect methods. This study tested the hypothesis that a change in anterior pelvic tilt causes elongation of the overall hamstring complex and disproportionately elongates proximal relative to distal muscle regions. METHODS: Seven fresh-frozen specimens (full lower limb with pelvis and lumbar spine) were used for this in vitro study. Specimens were dissected to enable visualization of the hamstring muscles and then fixed into a custom-made testing bench that allowed controlled movement of the pelvis over a fixed femur and tibia. Nine markers were inserted into the hamstring muscles to allow intra- and intermuscle difference measurements. Then, six different anterior pelvic angles were used to measure the difference in hamstring muscle lengthening through a three-dimensional reconstruction system based on stereoscopic machine vision technology. RESULTS: An increase in anterior pelvic tilt produced a significant non-uniform increase in tissue elongation in all regions of the three hamstring muscles (semitendinosus, semimembranosus [SMB] and biceps femoris long head), which was greater in the proximal (>1 cm every 5°) compared to the distal region (≈0.4 cm every 5°). At the proximal hamstring region, SMB showed significantly greater length changes compared to conjoint tendons with nonstatistically significant elongation differences between muscles at the distal region. CONCLUSION: Considering the results of the study, the pelvis segment will likely play a fundamental role as a strain regulator of hamstring muscles. These results will have an impact on injury rehabilitation and prevention processes of hamstring injuries, as well as optimize future musculoskeletal models and avoid potential underestimation of the hamstring muscle-tendon complex lengthening during high-speed running. LEVEL OF EVIDENCE: N/A.

Platelet-rich plasma does not accelerate the healing of damaged muscle following muscle strain.

Although platelet-rich plasma (PRP) has been widely used regardless of the severity of muscle strain, there have been very few basic studies in which its effects on muscle injury were examined by using models that accurately mimic the clinical muscle strain injury process. Therefore, the aim of this study was to confirm by physiological and structural analyses whether PRP purified by a general preparation method has a muscle healing effect on muscle damage caused by eccentric contraction (ECC). Male Wistar rats were subjected to muscle injury induced by ECC in bilateral plantar flexor muscles using electrical stimulation and an automatically dorsiflexing footplate. The rats were randomly assigned to three groups by type of injection: phosphate-buffered saline (PBS), leukocyte-poor PRP (LP-PRP), or leukocyte-rich PRP (LR-PRP) injection into gastrocnemius muscles three times at weekly intervals. The platelet concentrations of the LP-PRP and LR-PRP were three to five times higher than that of whole blood. The recovery process of torque strength in the plantar flexor muscle, signal changes in MRI images, and histological evaluation 3 weeks after injury showed no obvious differences among the three groups, and every muscle recovered well from the injury without marked fibrosis. The results that neither LP-PRP nor LR-PRP was found to accelerate healing of muscle injuries suggested that conventional preparation and use of PRP for simple muscle injuries caused by muscle strain should be carefully considered, and further basic research using models that accurately mimic clinical practice should be carried out to determine the optimal use of PRP.

UEFA Women's Elite Club Injury Study: a prospective study on 1527 injuries over four consecutive seasons 2018/2019 to 2021/2022 reveals thigh muscle injuries to be most common and ACL injuries most burdensome.

OBJECTIVE: Injuries in women's football (soccer) have scarcely been investigated, and no study has been conducted in the highest competitive level involving club teams from different countries. Our aim was to investigate the time-loss injury epidemiology and characteristics among women's elite football players over four seasons. METHODS: 596 players from 15 elite women's teams in Europe were studied prospectively during the 2018/2019 to 2021/2022 seasons (44 team seasons). Medical staff recorded individual player exposure and time-loss injuries. Injury incidence was calculated as the number of injuries per 1000 playing hours and injury burden as the number of days lost per 1000 hours. RESULTS: 1527 injuries were recorded in 463 players with an injury incidence of 6.7 (95% CI 6.4 to 7.0) injuries per 1000 hours and a nearly fourfold higher incidence during match play compared with training (18.4, 95% CI 16.9 to 19.9 vs 4.8, 95% CI 4.5 to 5.1; rate ratio 3.8, 95% CI 3.5 to 4.2). Thigh muscle injuries (hamstrings 12%, 188/1527, and quadriceps 11%, 171/1527) were the most frequent injury, while anterior cruciate ligament (ACL) injury had the highest burden (38.0 days lost per 1000 hours, IQR 29.2-52.1) with median days lost of 292 (IQR 246-334) days. Concussions constituted 3% (47/1527) of all injuries, with more than half of them (55%, 26/47) due to ball-related impact. CONCLUSION: An elite women's football team can expect approximately 35 time-loss injuries per season. Thigh muscle injury was the most common injury and ACL injury had the highest injury burden.

Common Markers of Muscle Damage Are Associated with Divergent Gene Expression Patterns after Eccentric Contractions.

PURPOSE: Unaccustomed eccentric (ECC) exercise evokes exercise-induced muscle damage (EIMD). Soreness, strength loss, and serum creatine kinase (CK) are often used to quantify EIMD severity. However, changes in these markers are not fully understood mechanistically. To test the hypothesis that muscle damage markers are associated with unique molecular processes, we correlated gene expression responses with variation in each marker post-ECC. METHODS: Vastus lateralis biopsies were collected from 35 young men 3 h post-ECC (10 sets of 10 maximal eccentric contractions; contralateral leg [CON] as control). Maximal isometric strength, soreness, and serum CK activity were assessed 24 h preexercise and every 24 h for 5 d post-ECC. Strength was also measured 10 min post-ECC. Over the 5 d after ECC, average peak strength loss was 51.5 ± 20%; average soreness increased from 0.9 ± 1.9 on a 100-mm visual analog scale to 39 ± 19; serum CK increased from 160 ± 130 to 1168 ± 3430 U·L -1 . Muscle RNA was used to generate gene expression profiles. Partek Genomics Suite correlated peak values of soreness, strength loss, and CK post-ECC with gene expression in ECC (relative to paired CON) using Pearson linear correlation ( P < 0.05) and repeated-measures ANOVA used to detect influence of ECC. RESULTS: After ECC, 2677 genes correlated with peak soreness, 3333 genes with peak strength loss, and 3077 genes with peak CK. Less than 1% overlap existed across all markers (16/9087). Unique genes included 2346 genes for peak soreness, 3032 genes for peak strength loss, and 2937 genes for peak CK. CONCLUSIONS: The largely unique molecular pathways associated with common indirect markers of EIMD indicate that each marker of "damage" represents unique mechanistic processes.

Betulin Accelerated the Functional Recovery of Injured Muscle in a Mouse Model of Muscle Contusion.

Muscle contusion is an injury to muscle fibers and connective tissues. It commonly happens in impact events, and could result in pain, swelling, and limited range of motion. Diclofenac is one of commonly used nonsteroidal anti-inflammatory drugs to alleviate pain and inflammation after injury. However, it can potentially cause some side effects including gastrointestinal complications and allergy. Betulin is a lupine-type pentacyclic triterpenoid. It is showed to have valuable pharmacological effects, but the physiological effect of betulin on muscle contusion has not been reported. This study aimed to explore the therapeutic effects of betulin on muscle contusion that produced by the drop-mass method in mice. C57BL/6 mice were randomly assigned to control (no injury), only drop-mass injury (Injury), diclofenac treatment (Injury+diclofenac), and betulin treatment (Injury+betulin) groups. Injury was executed on the gastrocnemius of the right hind limb, and then phosphate-buffered saline (PBS), diclofenac, or betulin were oral gavage administrated respectively for 7 days. Results revealed that betulin significantly restored motor functions based on locomotor activity assessments, rota-rod test, and footprints analysis. Betulin also attenuated serum creatine kinase (CK) and lactate dehydrogenase (LDH) levels after muscle injury. Neutrophil infiltration was alleviated and desmin levels were increased after betulin treatment. Our data demonstrated that betulin attenuated muscle damage, alleviated inflammatory response, improved muscle regeneration, and restored motor functions after muscle contusion. Altogether, betulin may be a potential compound to accelerate the repair of injured muscle.

Dynamic palmitoylation of STX11 controls injury-induced fatty acid uptake to promote muscle regeneration.

Different types of cells uptake fatty acids in response to different stimuli or physiological conditions; however, little is known about context-specific regulation of fatty acid uptake. Here, we show that muscle injury induces fatty acid uptake in muscle stem cells (MuSCs) to promote their proliferation and muscle regeneration. In humans and mice, fatty acids are mobilized after muscle injury. Through CD36, fatty acids function as both fuels and growth signals to promote MuSC proliferation. Mechanistically, injury triggers the translocation of CD36 in MuSCs, which relies on dynamic palmitoylation of STX11. Palmitoylation facilitates the formation of STX11/SNAP23/VAMP4 SANRE complex, which stimulates the fusion of CD36- and STX11-containing vesicles. Restricting fatty acid supply, blocking fatty acid uptake, or inhibiting STX11 palmitoylation attenuates muscle regeneration in mice. Our studies have identified a critical role of fatty acids in muscle regeneration and shed light on context-specific regulation of fatty acid sensing and uptake.

Hamstring muscle injuries in athletics.

Hamstring muscle injuries (HMI) are a common and recurrent issue in the sport of athletics, particularly in sprinting and jumping disciplines. This review summarizes the latest literature on hamstring muscle injuries in athletics from a clinical perspective. The considerable heterogeneity in injury definitions and reporting methodologies among studies still needs to be addressed for greater clarity. Expert teams have recently developed evidence-based muscle injury classification systems whose application could guide clinical decision-making; however, no system has been adopted universally in clinical practice, yet.The most common risk factor for HMI is a previously sustained injury, particularly early after return-to-sport. Other modifiable (e.g. weakness of thigh muscles, high-speed running exposure) and non-modifiable (e.g. older age) risk factors have limited evidence linking them to injury. Reducing injury may be achieved through exercise-based programs, but their specific components and their practical applicability remain unclear.Post-injury management follows similar recommendations to other soft tissue injuries, with a graded progression through stages of rehabilitation to full return to training and then competition, based on symptoms and clinical signs to guide the individual speed of the recovery journey. Evidence favoring surgical repair is conflicting and limited to specific injury sub-types (e.g. proximal avulsions). Further research is needed on specific rehabilitation components and progression criteria, where more individualized approaches could address the high rates of recurrent HMI. Prognostically, a combination of physical examination and magnetic resonance imaging (MRI) seems superior to imaging alone when predicting 'recovery duration,' particularly at the individual level.

Magnetic resonance imaging predicts the days lost from training and competition: evaluation of 56 indirect muscle injuries in professional football players.

BACKGROUND: Lower limb muscle injuries have a strong impact in training and official competitions stoppage for professional football players. This study aimed to explore the relationship between oedema-like changes found on magnetic resonance imaging (MRI) in acute indirect thigh injuries muscles and the time required for the athlete to return to individual training - "return to training" (RTT) and for full availability for official competitions - "return to play" (RTP). METHODS: Professional football players from 2017/2018 to 2021/2022 seasons top league team with clinical and ultrasound (US) diagnosis of acute hamstrings or quadriceps muscle injury, confirmed on 48/72h subsequent MRI, were included. MRI images were retrospectively re-evaluated. MRI parameters evaluated were cross-sectional area (CSA), cranio-caudal extension (CCE), distance to nearest insertion (DI) and volume (V). Univariate and multivariate analysis was performed to find factors related to RTT, RTP, and episodes of reinjuries. RESULTS: Thirty-four first traumatic muscle injuries met the inclusion criteria. The mean time to RTT and RTP was 22 (4-49) and 25 (4-55) days, respectively. CCE and V resulted as independent predictive MRI variables for the time to RTT (P=0.012) and RTP (P=0.02), respectively. Thresholds of CCE≥11.31 cm and V ≥19.5cc can predict a time to RTT≥22 days (Odds Ratio [OR] 9.5) and RTP≥25 days (OR 4.583), respectively. CONCLUSIONS: The decision on the time required for RTP is based on clinic and imaging evaluation; CCE and V of the MRI oedema-like changes help to define the prognosis of the injury.

The direct muscular origin of the semitendinosus: a pitfall in categorization of proximal hamstring tendon tears.

The ischial origin of the hamstring musculature is complex. While the conjoint tendon and semimembranosus are commonly discussed and understood by radiologists, there is a lesser-known origin of the semitendinosus along the inferior and medial surface of the ischium in the form of a broad direct muscular connection. This secondary origin is infrequently described in the radiology literature and is a potential pitfall during grading of semitendinosus injuries if the interpreting physician is unaware of its presence. In a proximal hamstring tendon tear, the direct muscular origin of the semitendinosus can be spared, torn along with the conjoint tendon, or remain intact and contribute to a vertical shearing injury of the semitendinosus myotendinous junction. Detailed knowledge of this anatomy and its imaging appearance in the setting of injury enables the reader to correctly diagnose these unique hamstring injuries.

Cell-Derived Extracellular Matrix Fiber Scaffolds Improve Recovery from Volumetric Muscle Loss.

There are currently no surgical procedures that effectively address the treatment of volumetric muscle loss (VML) injuries that has motivated the development of implantable scaffolding. In this study, the effectiveness of an allogenic scaffold fabricated using fibers built from the extracellular matrix (ECM) collected from muscle fibroblast cells during growth in culture was explored using a hindlimb VML injury (tibialis anterior muscle) in a rat model. Recovery outcomes (8 weeks) were explored in comparison with unrepaired controls as well previously examined allogenic scaffolds prepared from decellularized skeletal muscle (DSM) tissue (n = 9/sample group). At 8-week follow-up, we found that the repair of VML injuries using ECM fiber scaffolds in combination with an autogenic mince muscle (MM) paste significantly improved the recovery of peak contractile torque (79% ± 13% of uninjured contralateral muscle) when compared with unrepaired VML controls (57% ± 13%). Similar significant improvements were measured for muscle mass restoration (93% ± 10%) in response to ECM fiber+MM repair when compared with unrepaired VML controls (73% ± 13%). Of note, mass and contractile strength recovery outcomes for ECM fiber scaffolds were not significantly different from DSM+MM repair controls. These in vivo findings support the further exploration of cell-derived ECM fiber scaffolds as a promising strategy for the repair of VML injury with recovery outcomes that compare favorably with current tissue-sourced ECM scaffolds. Furthermore, although the therapeutic potential of ECM fibers as a treatment strategy for muscle injury was explored in this study, they could be adapted for high-throughput fabrication methods developed and routinely used by the textile industry to create a broad range of woven implants (e.g., hernia meshes) for even greater clinical impact.

Hamstring Strain Ultrasound Case Series: Dominant Semitendinosus Injuries in National Collegiate Athletic Association Division I Athletes.

Authors of previous studies of patients with acute hamstring strains have reported injury to the biceps femoris and semitendinosus (ST) in 50% to 100% and 0% to 30%, respectively. This retrospective case series of hamstring injuries in National Collegiate Athletic Association Division I collegiate athletes exhibited an injury pattern on ultrasound imaging that differed from what would be expected based on prior literature. We examined ultrasound images of 38 athletes with acute hamstring strains for injury location (proximal muscle, proximal myotendinous junction, midportion of muscle, distal muscle) and affected muscles (biceps femoris, ST, or semimembranosus). Twenty-six athletes (68.4%) injured the ST, and 9 athletes (23.7%) injured the biceps femoris long head. Most athletes (23, 60.5%) injured the proximal portion of the muscle or myotendinous junction. Though this study had many limitations, we demonstrated more frequent involvement of the ST and less frequent involvement of the biceps femoris than reported in the literature.

Effectiveness of cryo plus ultrasound therapy versus diathermy in combination with high-intensity laser therapy for pain relief in footballers with muscle injuries: A prospective study.

BACKGROUND: Muscle injuries are common traumatic events in the clinical practice of the rehabilitation field. There is still a gap in the scientific literature on the effectiveness of physical agent modalities in the management of muscle injuries in athletes. OBJECTIVE: The aim of this study was to assess the effectiveness of cryo plus ultrasound therapy com-pared to diathermy in combination with high-intensity laser therapy (HILT) for pain relief in professional footballers with muscle injuries. METHODS: A case-control study was conducted on 31 professional footballers with a muscle injury of the lower limbs. Of these, 17 patients, assigned to a Group A (AG), were treated with HILT and cryoultrasound therapy; the remaining 14 patients, assigned to a Group B (BG), underwent HILT and diathermy. We assessed the extent of the pain, the size of the muscle injury, frequency of recurrence and number of days to recovery, at the time of recruitment, at the end of the rehabilitation and 3 months after the injury. RESULTS: Group A athletes had a greater benefit on pain (4.65 ± 0.61 vs 3.24 ± 0.63; p< 0.05) and muscle injury recurrence. The return to play in the athletes of group A took place 4.73 days earlier. CONCLUSION: HILT and cryo plus ultrasound therapy, in combination with therapeutic exercise, rep-resent a valid strategy in the treatment of muscle injuries in professional footballers.

Traumatic muscle injury.

Traumatic muscle injury represents a collection of skeletal muscle pathologies caused by trauma to the muscle tissue and is defined as damage to the muscle tissue that can result in a functional deficit. Traumatic muscle injury can affect people across the lifespan and can result from high stresses and strains to skeletal muscle tissue, often due to muscle activation while the muscle is lengthening, resulting in indirect and non-contact muscle injuries (strains or ruptures), or from external impact, resulting in direct muscle injuries (contusion or laceration). At a microscopic level, muscle fibres can repair focal damage but must be completely regenerated after full myofibre necrosis. The diagnosis of muscle injury is based on patient history and physical examination. Imaging may be indicated to eliminate differential diagnoses. The management of muscle injury has changed within the past 5 years from initial rest, immobilization and (over)protection to early activation and progressive loading using an active approach. One challenge of muscle injury management is that numerous medical treatment options, such as medications and injections, are often used or proposed to try to accelerate muscle recovery despite very limited efficacy evidence. Another challenge is the prevention of muscle injury owing to the multifactorial and complex nature of this injury.

Time-loss Injuries among Female and Male Spanish Rink Hockey Players.

The present study describes the time-loss injuries among female and male athletes of the Spanish rink hockey league during the 2021/22 season.We performed a retrospective cohort study on time-loss injuries, whereby the athlete is prevented from participating in a training session or game because of the injury.A total of 463 athletes were included, with 326 (70.4%) senior male and 137 (29.6%) female. Two hundred and eighty-two time-loss injuries were recorded, the most common form being muscle injuries (112 episodes, 39.7%), especially those affecting the hip adductor muscles (52 episodes, 46.4% of muscle injuries). Most injuries were classified as mild (1-7 days of time-loss) and the median return-to-play was 9.5 days (range 1-180).Injury patterns were compared according to gender, position and moment: the results showed significant differences between senior males and females, between field players and goalkeepers, as well as between training and game, in terms of injury nature and type. The injury incidence proportion was significantly higher for field players compared to goalkeepers), and senior males had a significantly higher risk than senior females.The present study provides a starting point for studying and preventing injuries in rink hockey athletes.

Acute Distal Biceps Tendon Injury: Diagnosis and Treatment / Lesões agudas do tendão distal do bíceps: Diagnóstico e tratamento

Abstract Acute distal biceps injuries clinically present with sudden pain and acute loss of flexion and supination strength. The main injury mechanism occurs during the eccentric load of the biceps. The hook test is the most significant examination test, presenting the highest sensibility and specificity for this lesion. Magnetic resonance imaging, the gold standard imaging test, can provide information regarding integrity and identify partial and/or complete tears. The surgical treatment uses an anterior or double approach and several reattachment techniques. Although there is no clinical evidence to recommend one fixation method over the other, biomechanical studies show that the cortical button resists better to failure. Although surgical treatment led to an 89% rate of return to work in 14 weeks, the recovery of high sports performance occurred in 1 year, with unsustainable outcomes.

Resumo As lesões agudas do tendão distal do bíceps se apresentam, clinicamente, com uma dor súbita associada a perda aguda de força de flexão e supinação. Seu principal mecanismo de lesão ocorre durante contração excêntrica do bíceps. O "Hook Test" é o principal teste semiológico, sendo o mais sensível e específico. A ressonância magnética, exame padrão ouro para o diagnóstico, pode fornecer informações sobre a integridade, identificando as lesões parciais e/ou completas. O tratamento cirúrgico pode ser realizado por duas vias principais: anterior e por dupla via porém as técnicas de reinserção tendínea são diversas não havendo evidência clínica que recomende um método de fixação em detrimento ao outro; embora o botão cortical apresente maior resistência a falha nos estudos biomecânicos. Com o tratamento cirúrgico o retorno as atividades laborais foi de 89% em 14 semanas (média) porém ao esporte de alto rendimento o prazo foi longo, média de 1 ano, e não duradouro.