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Mourad Ghrairi,1,2 Shaival Dalal,3 Esther Esteban-García,4 Philippe Chomier,5 Xavier Valle,2 Ricard Pruna2 1Department of Sports Medicine, FIFA Medical Centre of Excellence, Dubai, United Arab Emirates; 2Department of Sports Medicine, FIFA Medical Centre of Excellence FC Barcelona, Barcelona, Spain; 3Department of Orthopedics and Sports Medicine, Arthro One Sports Injuries and Rehabilitation Centre, Ahmedabad, Gujarat, India; 4Department of Physiotherapy, FIFA Medical Centre of Excellence, Dubai, United Arab Emirates; 5Department of Rehabilitation, FIFA Medical Centre of Excellence, Dubai, United Arab EmiratesCorrespondence: Shaival Dalal, Arthro One Orthopaedic Centre, 4th Floor, NIRAMYA, Near Rajpath Club, Bodakdev, Ahmedabad, 380054, India, Tel +91-9904915211, Email shaival_dalal@yahoo.co.inPurpose: The SpeedCourt system has been confirmed as an effective and dependable tool for evaluating multi-directional change-of-direction (COD) maneuvers. It has also been employed in the rehabilitation process following Anterior Cruciate Ligament (ACL) injuries and for multi-directional training purposes. This study investigated by means of the SpeedCourt system determines 1) whether there is any difference in COD parameters and countermovement jumps (CMJ) between United Arab Emirates (UAE) and non-UAE professional footballers 2) whether there is any difference between the two lower limbs during change-of-direction manoeuvres.Methodology: This analysis included 100 professional football players from UAE or Non-UAE football clubs who were tested at FIFA Medical Centre of Excellence. With the help of Speedcourt system, 6-s tapping, countermovement jump (CMJ) and chase 15-s tests were performed. Comparison was done between UAE and non-UAE footballers and also between the dominant and non-dominant sides.Results: Out of the 100 players, 83 players were right foot dominant. Apart from the countermovement jump test, there was no significant difference in results between UAE and non-UAE football players. Average time to turn for dominant and non-dominant sides did not show any significant difference, for either group.Conclusion: There is no difference in 6-s tapping, Chase 15-s tests or limb asymmetry amongst UAE and Non-UAE footballers. However, the non-UAE footballers showed significantly better performance in Countermovement Jump Test. The data provide baseline values for forthcoming sports medicine research, which can be taken into account when creating injury prevention or return-to-sport protocols, particularly with regard to change of direction parameters and countermovement jump.Keywords: Speedcourt, rehabilitation, prevention, countermovement

Mourad Ghrairi,1–3 Tom Loney,1 Ricard Pruna,2,4 Nikos Malliaropoulos,2,5 Xavier Valle2,41College of Medicine, Mohammed Bin Rashid University of Medicine and Health Sciences, Dubai 505055, United Arab Emirates; 2European College of Sports and Exercise Physicians, Thessaloniki 54250, Greece; 3FIFA Medical Centre of Excellence Dubai, Dubai, 36868, United Arab Emirates; 4FIFA Medical Centre of Excellence FC Barcelona, Barcelona, Spain; 5The William Harvey Research Institute, Barts and the London, Centre for Sport and Exercise Medicine, Queen’s University London, London, UKBackground: Muscle injury is the most common type of injury in football. Previous research has focused on traditional risk factors (eg, age, injury history, muscle imbalance/inflexibility) contributing to muscle re-injury. The effect of poor cooperation between the coaching and medical teams on the risk of re-injury remains unexplored in the sports medicine football literature.Purpose: Examine the effect of poor cooperation between coaching and medical teams on muscle re-injury in professional football.Methods: Retrospective review of the medical files of 97 footballers of a professional team in Dubai over 15 consecutive seasons (2002–2017). Medical team recorded all injuries in each player’s file. Data on the perceived level of cooperation between coaching and medical teams were available in the daily meeting notes from the head of the medical team. The level of perceived cooperation was ranked on a three-point Likert scale by the head of the medical team and depended on whether the coaching team accepted the player injury (excellent cooperation), brought some suggestion after discussion with the medical team (normal cooperation) or rejected it (poor cooperation).Results: In total, 338 indirect muscle injuries (21 re-injuries) were recorded during 15 consecutive seasons., There was a significant increase in the mean number of total injuries (mean ± SE, 95% CI; 16±2, 12–21; P

Purpose: To define based on expert opinion and practical experience using a systematic and scientific approach, (1) the perceived most effective exercise-based strategies to prevent muscle injury in elite footballers; and, (2) when and how these exercise programs are prescribed based on the number of days between games i.e. implementation strategy. Methods: A Delphi survey obtained opinions and assessed for agreement. Delphi respondents consisted of 21 experienced sports practitioners (12 ± 5.3 years in elite football and with an academic background) belonging to 18 teams from the Big-5 European football leagues; England, France, Germany, Italy, Spain. Three teams were represented collaboratively by two experts. The Delphi process involves sequential rounds each evolving based on the responses from the previous. The number of rounds is not pre-defined and continues until an agreement is either achieved or it is clear that no agreement will be reached. Frequency of responses was recorded where the agreement was sought (i.e. in closed questions) and an agreement was achieved if ≥ 13/18 (70%) respondents agreed. For open-ended questions, a qualitative content analysis was performed to identify recurring themes and when themes were specified by ≥ 13 (70%), these were also considered as reaching an agreement. Practitioners had the opportunity to raise concerns if they disagreed with the 'agreement from recurrent themes'. Results: There were four Delphi rounds (100% response for each round). Sprinting and High-Speed Running (HSR) focused exercises were agreed as most effective (perceived) to prevent muscle injuries. Eccentric exercise was perceived as the next most effective. It was agreed that sprinting and HSR be integrated into coaches training, and target 100% of players worst-case match scenario (e.g. volume, intensity) based on individual maximum speeds. Eccentric exercise was recommended to be implemented according to the context of the main football session and planned/actual sprinting and HSR content. It was agreed that eccentrics can be performed before or after training, context dependent. The day to perform specific sprinting and HSR or eccentric exercises depended on the proximity of previous and upcoming matches. Other exercises reaching agreement as 'somewhat effective' included concentric and isometric, horizontal and vertical plyometrics, coordination, core and dynamic flexibility in addition to core stability. No agreement was reached for multi-joint, resisted sprinting, kicking or agility exercises nor simultaneous single-leg strength and stability. Finally, no agreement was reached regarding programming variables e.g. sets, repetitions as deemed too contextual. Conclusion: Regarding exercise-based strategies, particular importance agreed by the Delphi expert group was to focus on sprinting, HSR and eccentric exercises, integrated with a variety of other exercise modes which also carry some level of effectiveness in a multidimensional programme. Context was agreed to be key and decision-making about when to undertake/ how to prescribe exercise strategies to be made according to the content of normal football training and the proximity of matches. [ABSTRACT FROM AUTHOR]

Background: Making a diagnosis of proximal hamstring tendinopathy (PHT) may be challenging, as patients with correlating clinical symptoms may have normal or minimal findings on magnetic resonance imaging (MRI) scans., Purpose/hypothesis: The purpose of this study was to assess the effect of a novel hip flexion (HF) scanning position on the MRI diagnosis of PHT. It was hypothesized that the HF position, which simulates the symptom-provoking sitting position, would reveal PHT pathology more accurately than the standard scanning position., Study Design: Cohort study (diagnosis); Level of evidence, 3., Methods: Patients with chronic PHT symptoms were included. Chronicity was defined as symptoms that were present for >3 months. Each patient underwent an MRI in 2 parts: (1) the standard pelvic examination in the supine position and (2) the novel HF position in which the patient lays on his or her side with the hip at 90° of flexion. Tendon insertion areas of the semimembranosus and the biceps femoris were analyzed independently by 2 experienced musculoskeletal radiologists, and the findings were classified as normal , tendinosis , or rupture . The MRI findings for both the standard and HF positions were compared in every patient, and the percentage of different diagnoses between the 2 MRI positions was reported., Results: In total, 38 patients (67 tendons) were analyzed. In 71% of the patients, the HF position revealed more severe injury than the standard position. The HF position showed a rupture in 16% of the tendons, with findings classified as tendinosis in the standard position. Of the tendons diagnosed as normal in the standard position, 6% were classified as rupture and 11% as tendinosis in the HF position., Conclusion: The novel HF scanning position offered additional value in the diagnosis of PHT in symptomatic patients when compared with the standard hip-in-neutral position. This position can improve the diagnostics of PHT, especially if an athlete or an active patient with gluteal area pain has normal or minimal MRI findings in the standard position., Competing Interests: The authors declared that there are no conflicts of interest in the authorship and publication of this contribution. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto. Ethical approval for this study was obtained from Hospital District of Southwest Finland (ref No. 37/1801/2019)., (© The Author(s) 2024.)

Muscle functional MRI identifies changes in metabolic activity in each muscle and provides a quantitative index of muscle activation and damage. No previous studies have analyzed the hamstrings activation over a football match. This study aimed at detecting different patterns of hamstring muscles activation after a football game, and to examine inter- and intramuscular differences (proximal-middle-distal) in hamstring muscles activation using transverse relaxation time (T2)-weighted magnetic resonance images. Eleven healthy football players were recruited for this study. T2 relaxation time mapping-MRI was performed before (2 hours) and immediately after a match (on average 13 min). The T2 values of each hamstring muscle at the distal, middle, and proximal portions were measured. The primary outcome measure was the increase in T2 relaxation time value after a match. Linear mixed models were used to detect differences pre and postmatch. MRI examination showed that there was no obvious abnormality in the shape and the conventional T2 weighted signal of the hamstring muscles after a match. On the other hand, muscle functional MRI T2 analysis revealed that T2 relaxation time significantly increased at distal and middle portions of the semitendinosus muscle (p = 0.0003 in both cases). By employing T2 relaxation time mapping, we have identified alterations within the hamstring muscles being the semitendinosus as the most engaged muscle, particularly within its middle and distal thirds. This investigation underscores the utility of T2 relaxation time mapping in evaluating muscle activation patterns during football matches, facilitating the detection of anomalous activation patterns that may warrant injury reduction interventions., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Mechó et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

MRI plays a crucial role in assessment of patients with muscle injuries. The healing process of these injuries has been studied in depth from the pathophysiologic and histologic points of view and divided into destruction, repair, and remodeling phases, but the MRI findings of these phases have not been fully described, to our knowledge. On the basis of results from 310 MRI studies, including both basal and follow-up studies, in 128 athletes with muscle tears including their clinical evolution, the authors review MRI findings in muscle healing and propose a practical imaging classification based on morphology and signal intensity that correlates with histologic changes. The proposed phases, which can overlap, are destruction (phase 1), showing myoconnective tissue discontinuity and featherlike edema; repair (phase 2), showing filling in of the connective tissue gaps by a hypertrophic immature scar; and remodeling (phase 3), showing scar maturation and regression of the edema. A final healed stage can be identified with MRI, which is characterized by persistence of a slight fusiform thickening of the connective tissue. This information can be obtained from a truncated MRI protocol with three acquisitions, preferably performed with a 3-T magnet. During MRI follow-up of muscle injuries, other important features to be assessed are changes in muscle edema and specific warning signs, such as persistent intermuscular edema, new connective tear, and scar rupture. An understanding of the MRI appearance of normal and abnormal muscle healing and warning signs, along with cooperation with a multidisciplinary team, enable optimization of return to play for the injured athlete. © RSNA, 2024 See the invited commentary by Flores in this issue.

Objectives: Hamstring injuries are the most common muscle injuries in team sports. The aims of this study were to describe the epidemiology of hamstring muscle injuries in the professional and amateur sport sections of a multi-sport club Football Club Barcelona (FCB) and to determine any potential correlation between return-to-play (RTP) and injury location, severity of connective tissue damage, age, sex, and athlete's level of competition., Methods: This descriptive epidemiological study with data collected from September 2007 to September 2017 stored in the FCB database. The study included non-contact hamstring injuries sustained during training or competition., Results: A total of 538 hamstring injuries were reported in the club's database, of which 240 were structurally verified by imaging as hamstring injuries. The overall incidence for the 17 sports studied was 1.29 structurally verified hamstring injuries per 100 athletes per year. The muscle most commonly involved in hamstring injuries was the biceps femoris, and the connective tissue most frequently involved was the myofascial. There was no evidence of a statistically significant association between age and RTP after injury, and no statistically significant difference between sex and RTP. However, the time loss by professionals was shorter than for amateurs, and proximal hamstring injuries took longer RTP than distal ones., Conclusion: In the 17 sports practiced at multi-sport club, the incidence of hamstring injury was 1.29 per 100 athletes per year. Players from sports in which high-speed sprinting and kicking are necessary, and amateurs, were at higher risk of suffering a hamstring injury. In addition, proximally located hamstring injuries involving tendinous connective tissue showed the longest RTP time. Age did not seem to have any influence on RTP. Documenting location and the exact tissue involved in hamstring injuries may be beneficial for determining the prognosis and RTP.

Understanding the traumatic mechanisms of ankle injuries in soccer is crucial for an accurate and complete MRI diagnosis. Many ankle injuries share universal mechanisms seen in other athletic activities, but certain patterns are found to be more specific and relatively unique to soccer. Ankle impingement syndromes encountered in soccer encompass a spectrum of disorders that include anterior and posterior impingement categories, with anterior impingement representing pathology relatively specific to soccer. Lateral ligamentous sprains are one of the most common injuries; however, there is a higher rate of injuries to the medial structures in soccer as compared to other sports. Ankle fractures are uncommon in soccer while bone contusions and chondral and osteochondral injuries frequently accompany ligamentous sprains. Tendon abnormalities in soccer most commonly result from overuse injuries and typically affect peroneal tendons, posterior and anterior tibialis tendons, and Achilles tendon. Acute Achilles tendon ruptures occur in both recreational players and elite soccer athletes. Tibialis anterior friction syndrome may mimic tibial stress fractures. Long-term sequelae of acute traumatic and chronic overuse ankle injuries in professional soccer players manifest as ankle osteoarthritis that is more prevalent compared to not only the general population, but also to former elite athletes from other sports. This article examines the most common and specific injuries in soccer in order of their frequency., (© 2023. The Author(s), under exclusive licence to International Skeletal Society (ISS).)

Background: A comprehensive examination of the sport-specific activities and circumstances being performed at the time of injury is important to hypothesise mechanisms, develop prevention strategies and inform future investigations. Results reported in the literature are inconsistent because inciting activities are reported using different classifications. Hence the aim was to develop a standardised system for the reporting of inciting circumstances., Methods: The system was developed using a modified Nominal Group Technique. The initial panel included 12 sports practitioners and researchers from four continents with respectively ≥ 5 years of experience working in professional football and/or conducting injury research. The process consisted of six phases: idea generation, two surveys, one online meeting and two confirmations. For answers to the closed questions, consensus was deemed achieved if ≥ 70% of respondents agreed. Open-ended answers were qualitatively analysed and then introduced in subsequent phases., Results: Ten panellists completed the study. The risk of attrition bias was low. The developed system includes a comprehensive range of inciting circumstances across five domains: contact type, ball situation, physical activity, session details, contextual information. The system also distinguishes between a core set (essential reporting) and an optional set. The panel deemed all the domains to be important and easy to use both in football and in research environments., Conclusion: A system to classify inciting circumstances in football was developed. Given the extent of reporting inconsistency of inciting circumstances in the available literature, this can be used while further studies evaluate its reliability., (© 2023. The Author(s).)

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., Competing Interests: The authors report no conflicts of interest., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc.)

Objective: To describe the injury mechanisms and magnetic resonance imaging (MRI) findings in acute hamstring injuries of male soccer players using a systematic video analysis., Design: Descriptive case series study of consecutive acute hamstring injuries from September 2017 to January 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 an acute hamstring injury, with an available video footage of the injury and positive finding on MRI., Independent Variables: Hamstring injury mechanisms (specific scoring based on standardized models) in relation to hamstring muscle injury MRI findings., Main Outcome Measures: Hamstring injury mechanism (playing situation, player/opponent behavior, movement, and biomechanical body positions) and MRI injury location., Results: Fourteen videos of acute hamstring injuries in 13 professional male soccer players were analyzed. Three different injury mechanisms were seen: mixed-type (both sprint-related and stretch-related, 43%), stretch-type (36%), and sprint-type (21%). Most common actions during injury moments were change of direction (29%), kicking (29%), and running (21%). Most injuries occurred at high or very high horizontal speed (71%) and affected isolated proximal biceps femoris (BF) (36%). Most frequent body positions at defined injury moments were neutral trunk (43%), hip flexion 45-90 degrees (57%), and knee flexion <45 degrees (93%). Magnetic resonance imaging findings showed that 79% were isolated single-tendon injuries., Conclusions: According to a video analysis, most hamstring injuries in soccer occur during high-speed movements. Physicians should suspect proximal and isolated single-tendon-most often BF-hamstring injury, if represented injury mechanisms are seen during game play. In addition to sprinting and stretching, also mixed-type injury mechanisms occur., Competing Interests: The authors report no conflicts of interest., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc.)

Objective: To present unprecedented radiological parameters that characterize the angle between the direct and indirect tendons of the proximal rectus femoris (RF) and its inclinations and to evaluate the population variability according to demographic variables. Materials and methods: From September 2019 to July 2021, using MRI multiplanar reconstructions of the proximal thigh/hip, two blinded radiologists measured the direct and indirect tendon angle and the inclination of each tendon in different planes. The intra- and inter-observer agreements were assessed with Bland-Altman analysis and intraclass correlation coefficient (ICC). The correlations between radiological parameters and demographic variables were evaluated using linear regression, Student's t- test, and analysis of variance. Results: We performed 112 thigh/hip MRI scans on 91 football players of different age, gender, and disciplines (football and futsal). For observer 1 (the reference), the mean direct and indirect tendon angle was 56.74° ± 9.37, the mean indirect tendon slope was -7.90° ± 7.49, and the mean direct tendon slope was 22.16° ± 5.88. The three measurements showed inter- and intra-observer agreement (mean differences ∼0). No correlation was observed between age and the parameters. Likewise, no statistically significant differences were found for gender, dominant limb, examined limb, and sport. Conclusion: There is an inter- and intra-observer agreement in the measurements of the direct and indirect tendon angle and the inclination of each tendon. There is population variability in the proximal tendinous complex unrelated to demographic factors. These results allow further detection of morphological patterns that represent a risk factor for lesions in the RF in professional football and futsal players and other sports., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Mechó, Lisbona Ortega, Pruna, Nescolarde Selva, Morillas Pérez, Rodríguez-Baeza, Martínez Agea and Pérez-Andrés.)

Background: Because MRI has shown great accuracy in assessing acute muscle injuries, identification of risk factors for reinjury before return to play (RTP) in professional athletes during the healing process could be very relevant. We assessed the value of MRI findings prior to RTP as predictors of reinjury., Methods: Retrospective observational study of 59 professional athletes, mean age 26 years, with first-time acute muscle injury and successful rehabilitation ready to RTP. They underwent MRI within 6 days of the injury and within 7 days prior to RTP. The primary outcome was reinjury. Risk of reinjury was assessed using radiological signs in control MRI scans before RTP. The risk was classified as low, medium or high when none, one or two radiological signs were observed, respectively., Results: Reinjury occurred in 9 participants, with a rate of 15.2%. None of the baseline MRI-related variables was significantly associated with reinjury. In the control MRI scan performed within 7 days prior to RTP, three independent findings were significantly associated with reinjury. These included transversal and/or mixed connective tissue gap (p = 0.002), intermuscular oedema (p = 0.015) and callus gap (p = 0.046). In the predictive model of the risk of reinjury, the presence of two of these radiological signs, together with interstitial feathery oedema, was associated with a high risk of recurrence (OR 29.58, 95% CI 3.86-226.64; p = 0.001)., Conclusions: In professional athletes with acute muscle injuries of the lower limbs successfully rehabilitated, some radiological signs on MRI performed shortly before RTP were associated with a high risk of reinjury., (© 2022. The Author(s).)

Robotic technology offers excellent visualization and surgical precision but has not been established for aortic valve surgery. We present the first 2 cases of patients with severe aortic stenosis who underwent successful robotic aortic valve replacement using a lateral approach and the Edwards Intuity® rapid-deployment bioprosthesis. Postoperative recovery was excellent, and both patients were discharged home on the fourth postoperative day. We believe this approach is valuable for robotic aortic valve replacement and may help to finally bridge the gap into routine clinical use, becoming a valuable option for the surgical treatment of the aortic valve in selected patients.

Background and Objective: Muscle injuries are one of the main daily problems in sports medicine, football in particular. However, we do not have a reliable means to predict the outcome, i.e. return to play from severe injury. The aim of the present study was to evaluate the capability of the MLG-R classification system to grade hamstring muscle injuries by severity, offer a prognosis for the return to play, and identify injuries with a higher risk of re-injury. Furthermore, we aimed to assess the consistency of our proposed system by investigating its intra-observer and inter-observer reliability., Methods: All male professional football players from FC Barcelona, senior A and B and the two U-19 teams, with injuries that occurred between February 2010 and February 2020 were reviewed. Only players with a clinical presentation of a hamstring muscle injury, with complete clinic information and magnetic resonance images, were included. Three different statistical and machine learning approaches (linear regression, random forest, and eXtreme Gradient Boosting) were used to assess the importance of each factor of the MLG-R classification system in determining the return to play, as well as to offer a prediction of the expected return to play. We used the Cohen's kappa and the intra-class correlation coefficient to assess the intra-observer and inter-observer reliability., Results: Between 2010 and 2020, 76 hamstring injuries corresponding to 42 different players were identified, of which 50 (65.8%) were grade 3 r , 54 (71.1%) affected the biceps femoris long head, and 33 of the 76 (43.4%) were located at the proximal myotendinous junction. The mean return to play for grades 2, 3, and 3 r injuries were 14.3, 12.4, and 37 days, respectively. Injuries affecting the proximal myotendinous junction had a mean return to play of 31.7 days while those affecting the distal part of the myotendinous junction had a mean return to play of 23.9 days. The analysis of the grade 3 r biceps femoris long head injuries located at the free tendon showed a median return to play time of 56 days while the injuries located at the central tendon had a shorter return to play of 24 days (p = 0.038). The statistical analysis showed an excellent predictive power of the MLG-R classification system with a mean absolute error of 9.8 days and an R-squared of 0.48. The most important factors to determine the return to play were if the injury was at the free tendon of the biceps femoris long head or if it was a grade 3 r injury. For all the items of the MLG-R classification, the intra-observer and inter-observer reliability was excellent (k > 0.93) except for fibres blurring (κ = 0.68)., Conclusions: The main determinant for a long return to play after a hamstring injury is the injury affecting the connective tissue structures of the hamstring. We developed a reliable hamstring muscle injury classification system based on magnetic resonance imaging that showed excellent results in terms of reliability, prognosis capability and objectivity. It is easy to use in clinical daily practice, and can be further adapted to future knowledge. The adoption of this system by the medical community would allow a uniform diagnosis leading to better injury management., (© 2022. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Introduction: Rectus femoris injuries are common in sports requiring sprinting and kicking, especially in football. In addition to sports injuries, rectus femoris injuries can occur during physically active daily living and physical work. Most muscle injuries heal well by conservative treatment, but more severe ruptures often require surgical treatment, especially in athletes. Some ruptures can cause so severe functional loss of the muscle that it causes problems also in everyday life. Complete rectus femoris mid-substance rupture is a rare injury type, which tends to recover poorly and cause significant functional deficit. Descriptions of this injury type are mainly lacking in the literature and there is no consensus on the management of these injuries. To the best of our knowledge, this is the first report of this kind in the literature including strength measurements pre- and post-operatively., Case Report: We report a case of a 48-year-old Caucasian man who suffered a complete rectus femoris mid-substance rupture at physically active work. The injury mechanism was slipping on an asphalt ramp, leading to rapid eccentric contraction of rectus femoris involving knee flexion and hip extension. The rupture was treated surgically and the muscle strength of quadriceps femoris was measured pre- and postoperatively., Conclusion: This case report showed that muscle strength in knee extension recovers well after an operative treatment of complete rectus femoris mid-substance rupture. Therefore, it can be concluded that operative treatment is beneficial for this specific injury type. This case report brings important and objective evidence on the relevance of surgical treatment in these injuries that are mainly lacking the consensus about the best treatment methods. To the best of our knowledge, this case report is also the first one which indirectly shows the value of isolated rectus femoris muscle in the whole quadriceps muscle group., Competing Interests: Conflict of Interest: Nil, (Copyright: © Indian Orthopaedic Research Group.)

Most of the anterior thigh injuries are contusions or strains, however, some of these injuries can be career ending. Early diagnosis and correct treatment are key to successful outcome. Analyzing injury mechanism and adding both clinical and imaging findings, clinicians can make the right treatment decisions already often in the acute phase of the injury. Low grade contusions and muscle strains are treated well with planned rehabilitation, but complete tendon injuries or avulsions can require operative treatment. Also, neglected minor injuries could lead to chronic disabilities and time lost from play. Typical clinical presentation of anterior thigh injury is swelling and pain during hip flexion or knee extension. In more severe cases a clear gap can be palpated. Imaging methods used are ultrasound and magnetic resonance imaging (MRI) which are helpful for clinicians to determine more exact the extent of injury. MRI can identify possible tendon retractions which may need surgery. Clinicians should also be aware of other traumatic lesions affecting anterior thigh area such as myositis ossificans formation. Optimal treatment should be coordinated including acute phase treatment with rest, ice, and compression together with designed return-to-play protocol. The anatomical structure involved lines the treatment pathway. This narrative review describes these more common reasons for outpatient clinical visits for anterior thigh pain and injuries among soccer players., (© 2022. The Author(s).)

Objectives: Hamstring injuries are common and can now be accurately diagnosed. In addition, novel surgical indications have been introduced. However, evidence-based guidelines on the hamstring injuries in management of top-level athletes are missing., Methods: The management methods and outcomes of treatment are classically based on relatively small case series. We discuss a novel concept based on the fact that each tendon of the hamstrings muscle should be managed in an individual fashion. Furthermore, suitable indications for hamstring surgery in athletes are introduced., Results: The present study introduces modern treatment principles for hamstring injury management. Typical clinical and imagining findings as well as surgical treatment are presented based on a critical review of the available literature and personal experience., Conclusions: Hamstring injuries should not be considered to be all equal given the complexity of this anatomical region: The three separate tendons are different, and this impacts greatly on the decision-making process and outcomes in athletes.

Background: Severe rectus femoris central tendon rupture is an uncommon sports-related injury. Most rectus femoris central tendon injuries can be treated by nonoperative means, but some tend to reinjure, resulting in chronic symptoms. Physicians treating athletes with rectus femoris injuries should be aware of this clinical condition and know that surgical treatment could be beneficial to the athlete if the rectus femoris central tendon rupture becomes chronic., Purpose: To describe the clinical picture, magnetic resonance imaging (MRI) findings, and surgical treatment results of rectus femoris central tendon injuries., Study Design: Case series; Level of evidence, 4., Methods: This study included 12 patients who underwent successful repair of recurrent rectus femoris central tendon rupture. Presurgical MRI scans were obtained and compared with the surgical findings. The time of return to play was recorded, and the outcome of surgical treatment was evaluated with validated Subjective Patient Outcome for Return to Sports (SPORTS) criteria: good = full return to preinjury level of sports without any symptoms; moderate = return to preinjury level of sports with some residual symptoms (mild discomfort during sports); and poor = did not return to preinjury level of sports., Results: Overall, 10 patients had a good outcome (83%), and 2 had a moderate outcome (17%). All athletes included in the study were able to return to sport at their preinjury levels 2.5 to 4 months postoperatively. Presurgical MRI scans correlated well with the surgical findings., Conclusion: The surgical treatment of rectus femoris central tendon rupture seems to be a good option in chronic and recurrent cases. After surgery and successful rehabilitation, the athlete is expected to continue sports at the preinjury level., Competing Interests: The authors declared that there are no conflicts of interest in the authorship and publication of this contribution. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto., (© The Author(s) 2021.)

Hamstring strain injury (HSI) remains the most common muscle injury in high-intensity running in humans. The majority of acute HSI occur specifically within the proximal region of the long head of biceps femoris and there is a sustained interest among researchers in understanding the factors that predispose to HSI. The present critical review describes the current understanding of biceps femoris long head (BFlh) structural features that might influence strain injury risk. Inter-individual differences in muscle-tendon architecture and interactions, muscle fiber type and region-specific innervation are likely to influence biceps femoris long head injury risk and might inform why some individuals are at an increased risk of sustaining a HSI during running. However, more research is needed, with future studies focusing on prospective data acquisition, improved computer simulations and direct imaging techniques to better understand the relationship between structural features, hamstring muscle function, and injury risk.

More than 250,000 anterior cruciate ligament (ACL) injuries occur each year in the USA, and approximately 65% of these injuries undergo reconstructive surgery. Appropriate rehabilitation after ACL reconstruction can yield predictably good outcomes, with return to previous levels of activity and high knee function. At present, periodization is used at all levels of sports training. Whether conceptualized and directed by coaches, or by athletes themselves, competitors structure their training in a cyclic fashion, enabling athletes to best realize their performance goals. In practical application, sport physical therapists use periodization: postoperative "protocols" serve as rudimentary forms of periodization, albeit implemented over shorter time frames than that typically employed in preparation for competition. An ACL injury should not be considered a "simple" musculoskeletal pathology with only local mechanical or motor dysfunctions. Together with the psychological trauma and reduction in physical capacity, there is a cascade of events, including neurological insult to the central nervous system and reduction in afferences to the sensorimotor system. Rehabilitation should consider all these issues, and periodization would allow to better define and to plan aims and objectives to return athletes to their sport. Technological resources including advanced neuroimaging methods, virtual reality for injury risk screening and return to sport assessment, and interactive artificial reality-based neuromuscular training methods offer new approaches and tools to address this important biomedical problem. The cost and availability of many of these technologies will continue to decrease, providing greater availability, scientific rigor, and ultimately, utility for cost-effective and data-driven assessments., (© 2020 The Author(s) Published by S. Karger AG, Basel.)

Introduction: Football is characterised by intermittent high-intensity efforts varying according to the field position of a player. We aimed to ascertain whether polymorphisms in the ACTN3 gene are associated with different playing positions in elite professional football players., Subjects and Methods: Genotyping of the ACTN3 gene was conducted in 43 elite professional football players of a single team. Playing position was recorded based on the player's most frequent position., Results: The genotype distribution was not significant between positions (p = 0.057), while the allele distribution differed significantly (p = 0.035). Goalkeepers (p = 0.04, p = 0.03), central defenders (p = 0.03, p = 0.01), and central midfielders (p = 0.01, p = 0.00) had a significantly different allele distribution compared with wide midfielders and forward players., Conclusions: Genetic biomarkers may be important when analysing performance capability in elite professional football. Identifying the genetic characteristics of a player to adapt his playing position may lead to orientation of positions based on physical capabilities and tissue quality in young football players, and also to performance enhancement in those who are already playing in professional teams., (© 2020 The Author(s) Published by S. Karger AG, Basel.)

Muscle injuries of the lower limbs are currently the most common sport-related injuries, the impact of which is particularly significant in elite athletes. MRI is the imaging modality of choice in assessing acute muscle injuries and radiologists play a key role in the current scenario of multidisciplinary health care teams involved in the care of elite athletes with muscle injuries. Despite the frequency and clinical relevance of muscle injuries, there is still a lack of uniformity in the description, diagnosis, and classification of lesions. The characteristics of the connective tissues (distribution and thickness) differ among muscles, being of high variability in the lower limb. This variability is of great clinical importance in determining the prognosis of muscle injuries. Recently, three classification systems, the Munich consensus statement, the British Athletics Muscle Injury classification, and the FC Barcelona-Aspetar-Duke classification, have been proposed to assess the severity of muscle injuries. A protocolized approach to the evaluation of MRI findings is essential to accurately assess the severity of acute lesions and to evaluate the progression of reparative changes. Certain MRI findings which are seen during recovery may suggest muscle overload or adaptative changes and appear to be clinically useful for sport physicians and physiotherapists.

Injuries exert an enormous impact on athletes and teams. This is seen especially in professional soccer, with a marked negative impact on team performance and considerable costs of rehabilitation for players. Existing studies provide some preliminary understanding of which factors are mostly associated with injury risk, but scientific systematic evaluation of the potential of statistical models in forecasting injuries is still missing. Some factors raise the risk of a sport injury, but there are also elements that predispose athletes to sports injuries. The biological mechanisms involved in non-contact musculoskeletal soft tissue injuries are poorly understood. Genetic risk factors may be associated with susceptibility to injuries, and may exert marked influence on recovery times. Athletes are complex systems, and depend on internal and external factors to attain and maintain stability of their health and their performance. Organisms, participants or traits within a dynamic system adapt and change when factors within that system change. Scientists routinely predict risk in a variety of dynamic systems, including weather, political forecasting and projecting traffic fatalities and the last years have started the use of predictive models in the human health industry. We propose that the use of artificial intelligence may well help in assessing risk and help to predict the occurrence of sport injuries., Competing Interests: Declaration of Competing Interest The authors declare that there are no conflicts of interest., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

In recent years, different classifications for muscle injuries have been proposed based on the topographic location of the injury within the bone-tendon-muscle chain. We hereby propose that in addition to the topographic classification of muscle injuries, a histoarchitectonic (description of the damage to connective tissue structures) definition of the injury be included within the nomenclature. Thus, the nomenclature should focus not only on the macroscopic anatomy but also on the histoarchitectonic features of the injury., (© The Author(s) 2020.)

Introduction: Anterior cruciate ligament (ACL) tears are common, with a seemingly constant increase in their number, and potentially serious consequences for sports participation and long-term general and musculoskeletal health., Areas of Agreement: Most players are able to return to cutting sport after ACL reconstruction, but some sustain further knee problems needing different approach to their rehabilitation., Growing Points: Neurocognitive tasks, measuring reaction time, processing speed, visual memory and verbal memory, allow indirect assessment of cerebral performance. Situational awareness, arousal, and attentional resources may influence neurocognitive function, affecting the complex integration of vestibular, visual, and somatosensory information needed for neuromuscular control., Areas of Controversy: The underlying reasons for uncoordinated, high-velocity movements observed during non-contact injuries of the knee producing an ACL tear are not well understood. Fundamental neuropsychological characteristics are responsible for situational awareness, sensory integration, motor planning, and coordination, all of which control joint stiffness. There is a strong link between acquisition of motor skills and neuronal plasticity at cortical and subcortical levels in the central nervous system; these links may evolve over time and engage different spatially distributed interconnected brain regions. A cascade of neurophysiological alterations occurs after ACL injury., Areas Timely for Developing Research: Training can improve function; hence, rehabilitation programmes which include perturbation training, agility training, vision training and sport-specific skill training are essential after ACL injuries and for injury prevention, and to optimize return to play., Competing Interests: Conflict of interestThe authors declare that there are no personal or commercial relationships related to this study that would lead to a conflict of interest., (© Indian Orthopaedics Association 2020.)

Purpose: Muscle injuries are common in professional football, even though prevention protocols are being implemented. Genetics constitutes a novel field for studying intrinsic injury risks and performance. Since previous studies involving single nucleotide polymorphisms (SNPs) have shown that SNPs influence muscle injury rate, injury severity and recovery time, the aim was to study the association the SNP of ACTN3 has with those parameters in professional football players., Methods: The medical staff team recorded non-contact musculoskeletal soft-tissue injuries in 43 professional football players in 7 different seasons (2007-2012 and 2015-2016). Injury rate, injury severity and injury recovery times were established. Players were genotyped by extracting DNA from a blood sample and using a polymerase chain reaction., Results: Injury rate was associated with the SNP of ACTN3 (p = 0.003). The 577R allele was more frequent in subjects than in a normal population by showing presence in 93% of the subjects and suggesting that it could influence football performance. No statistically significant differences in injury severity and recovery time were associated with the SNP of ACTN3., Conclusions: Genetics is gaining in importance when assessing injury risk and performance in professional football. ACTN3 can be regarded as a biomarker of injury susceptibility in this discipline. Identifying those players with the highest injury susceptibility through genetics could lead football teams to individualise workloads and prevention protocols., Level of Evidence: III.

Purpose: The authors investigated the association between risk of tendinopathies and genetic markers in professional team sports., Methods: The authors studied 363 (mean [SD]; 25 [6] y, 89% male) elite players (soccer, futsal, basketball, handball, and roller hockey) from a top-level European team (FC Barcelona, Spain). Of 363, 55% (cases) had experienced 1+ episodes of tendinopathy during 2008-2018 and 45% (controls) remained injury free. The authors first examined the association between single-nucleotide polymorphisms (SNPs) and tendinopathy risk in a hypothesis-free case-control genome-wide association study (495,837 SNPs) with additional target analysis of 58 SNPs that are potential candidates to influence tendinopathy risk based on the literature. Thereafter, the authors augmented the SNP set by performing synthetic variant imputation (1,419,369 SNPs) and then used machine learning-based multivariate modeling (support vector machine and random forest) to build a reliable predictive model., Results: Suggestive association (P < 10-5) was found for rs11154027 (gap junction alpha 1), rs4362400 (vesicle amine transport 1-like), and rs10263021 (contactin-associated protein-like 2). Carriage of 1+ variant alleles for rs11154027 (odds ratio = 2.11; 95% confidence interval, 1.07-4.19, P = 1.01 × 10-6) or rs4362400 (odds ratio = 1.98; 95% confidence interval, 1.05-3.73, P = 9.6 × 10-6) was associated with a higher risk of tendinopathy, whereas an opposite effect was found for rs10263021 (odds ratio = 0.42; 95% confidence interval, 0.20-0.91], P = 4.5 × 10-6). In the modeling approach, one of the most robust SNPs was rs10477683 in the fibrillin 2 gene encoding fibrillin 2, a component of connective tissue microfibrils involved in elastic fiber assembly., Conclusions: The authors have identified previously undescribed genetic predictors of tendinopathy in elite team sports athletes, notably rs11154027, rs4362400, and rs10263021.

Nanostructured indium tin oxide (ITO) surfaces present an interesting yet unusual combination of properties (high electrical conductivity and optical transparency) at a high surface-to-volume ratio. Thus, previous studies presented nanostructured ITO electrodes as potentially suitable platforms for electrochemical biosensors, but still there is a lack of research on the optimization of preparation methods for such electrodes. We present a systematic study on the properties of nanostructured ITO electrodes prepared by physical deposition, where the substrate temperature was tuned for achieving the best combination of structural properties (namely electrical conductivity and optical transparency) and electrochemical performance. Analysis of faradaic cyclic voltammetry (CV) was performed to determine the electroactive surface area of the samples, and these results were benchmarked against those obtained by non-faradaic CV and Mott-Schottky (MS) analysis. The latter was useful to determine the dependence of some intrinsic features of the semiconductor on the substrate temperature during deposition. The results show that, out of a wide temperature range covering from 200 °C to 500 °C, there is a two-phase temperature-dependent growth, explained by the Stranski-Krastanov and self-catalytic vapor-liquid-solid (VLS) methods, and, on the other hand, that there is an optimal growth temperature at 300 °C that maximizes the electroactive surface area and sensitivity. This means that cost-effective electrodes can be prepared at low temperatures outperforming in terms of electroactive surface area, surface capacitance and sensitivity. As a proof-of-concept, nanostructured ITO electrodes were electrochemically derivatized with aryl diazonium salts (as a first step towards biochemical functionalization), and the performance of the optimized electrodes was tested in a real scenario.

Background: In adults, hamstring injuries may lead to long periods of rehabilitation and carry a definite risk of recurrence. However, no studies detail how these injuries affect young athletes., Objective: To describe and analyze injuries in the hamstring area in young athletes. To identify risk factors for injuries to the hamstring area in this age group, which will make it possible to design and optimize prevention plans., Methods: The study population consisted of 1157 young athletes with an average age of 13.56 years, all members of the Barcelona Football Club. Injuries to the hamstring area over three consecutive seasons (from July 2007 to June 2010) were analyzed., Results: The 50 injuries in the hamstring muscle complex included 14 injuries to the biceps femoris, 17 to the semitendinosus-semimembranosus complex, 10 cases of delayed onset muscle soreness (DOMS), and nine avulsion of the ischial tuberosity. Hamstring injuries were first identified in young athletes starting from age nine, with an age-related increased rate up to the age of 15, and a lower incidence at age 14, 16, and 18. The average time lost following an hamstring injury was 21 days and 43.4 days following avulsion from the ischium. The highest incidence of injuries occurred in football players., Conclusions: Hamstring injuries in this group of young athletes are less prevalent than in adults., (© 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Proximal rectus femoris (PRF) tears are relatively rare injuries among top-level athletes. PRF injuries can be avulsions of both tendon heads (direct and reflected heads) or of a single head, and some have a tendency to progress to recurrent injuries., Purpose: To describe a series of operatively treated PRF ruptures in professional soccer players., Study Design: Case series; Level of evidence, 4., Methods: Nineteen cases of PRF injuries (18 patients, 1 bilateral) in professional soccer players who were treated surgically were retrospectively reviewed. Perioperative findings with return-to-play data were recorded., Results: Of the PRF injuries, 10 total avulsions (both heads) and 9 single-head tears were seen on magnetic resonance imaging and were later confirmed during surgery. All 18 patients returned to their preinjury level of play (mean follow-up, 2.8 years [range, 1-11 years])., Conclusion: The repair of PRF tears in professional soccer players yielded good results and allowed all patients to return to their preinjury level of play., Competing Interests: The authors declared that they have no conflicts of interest in the authorship and publication of this contribution. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto.