Baseline clinical and MRI risk factors for hamstring reinjury showing the value of performing baseline MRI and delaying return to play: a multicentre, prospective cohort of 330 acute hamstring injuries.

OBJECTIVES: Studies identifying clinical and MRI reinjury risk factors are limited by relatively small sample sizes. This study aimed to examine the association between baseline clinical and MRI findings with the incidence of hamstring reinjuries using a large multicentre dataset. METHODS: We merged data from four prospective studies (three randomised controlled trials and one ongoing prospective case series) from Qatar and the Netherlands. Inclusion criteria included patients with MRI-confirmed acute hamstring injuries (<7 days). We performed multivariable modified Poisson regression analysis to assess the association of baseline clinical and MRI data with hamstring reinjury incidence within 2 months and 12 months of follow-up. RESULTS: 330 and 308 patients were included in 2 months (31 (9%) reinjuries) and 12 months (52 (17%) reinjuries) analyses, respectively. In the 2-month analysis, the presence of discomfort during the active knee extension test was associated with reinjury risk (adjusted risk ratio (ARR) 3.38; 95% CI 1.19 to 9.64). In the 12 months analysis, the time to return to play (RTP) (ARR 0.99; 95% CI 0.97 to 1.00), straight leg raise angle on the injured leg (ARR 0.98; 95% CI 0.96 to 1.00), the presence of discomfort during active knee extension test (ARR 2.52; 95% CI 1.10 to 5.78), the extent of oedema anteroposterior on MRI (ARR 0.74; 95% CI 0.57 to 0.96) and myotendinous junction (MTJ) involvement on MRI (ARR 3.10; 95% CI 1.39 to 6.93) were independently associated with hamstring reinjury. CONCLUSIONS: Two clinical findings (the presence of discomfort during active knee extension test, lower straight leg raise angle on the injured leg), two MRI findings (less anteroposterior oedema, MTJ involvement) and shorter time to RTP were independently associated with increased hamstring reinjury risk. These findings may assist the clinician to identify patients at increased reinjury risk following acute hamstring injury. TRIAL REGISTRATION NUMBERS: NCT01812564; NCT02104258; NL2643; NL55671.018.16.

Long-term cardiac follow-up of athletes infected with SARS-CoV-2 after resumption of elite-level sports.

OBJECTIVE: Longitudinal consequences and potential interactions of COVID-19 and elite-level sports and exercise are unclear. Therefore, we determined the long-term detrimental cardiac effects of the interaction between SARS-CoV-2 infection and the highest level of sports and exercise. METHODS: This prospective controlled study included elite athletes from the Evaluation of Lifetime participation in Intensive Top-level sports and Exercise cohort. Athletes infected with SARS-CoV-2were offered structured, additional cardiovascular screenings, including cardiovascular MRI (CMR). We compared ventricular volumes and function, late gadolinium enhancement (LGE) and T1 relaxation times, between infected and non-infected elite athletes, and collected follow-up data on cardiac adverse events, ventricular arrhythmia burden and the cessation of sports careers. RESULTS: We included 259 elite athletes (mean age 26±5 years; 40% women), of whom 123 were infected (9% cardiovascular symptoms) and 136 were controls. We found no differences in function and volumetric CMR parameters. Four infected athletes (3%) demonstrated LGE (one reversible), compared with none of the controls. During the 26.7 (±5.8) months follow-up, all four athletes resumed elite-level sports, without an increase in ventricular arrhythmias or adverse cardiac remodelling. None of the infected athletes reported new cardiac symptoms or events. The majority (n=118; 96%) still participated in elite-level sports; no sports careers were terminated due to SARS-CoV-2. CONCLUSIONS: This prospective study demonstrates the safety of resuming elite-level sports after SARS-CoV-2 infection. The medium-term risks associated with SARS-CoV-2 infection and elite-level sports appear low, as the resumption of elite sports did not lead to detrimental cardiac effects or increases in clinical events, even in the four elite athletes with SARS-CoV-2 associated myocardial involvement.

Platelet-Rich Plasma Injections for the Treatment of Ankle Osteoarthritis.

BACKGROUND: Ankle osteoarthritis is debilitating and usually affects relatively young people, often as a result of previous ankle traumas, frequently occurring in sports. Platelet-rich plasma (PRP) injections for ankle osteoarthritis have shown no evidence of benefit over the course of 26 weeks. Previous studies on PRP for knee osteoarthritis showed that clinically significant improvements with PRP occurred between 6 to 12 months in the absence of initial benefit. No studies have evaluated the effect of PRP from 6 to 12 months in ankle osteoarthritis. PURPOSE: To assess the efficacy of PRP injections in ankle osteoarthritis over the course of 52 weeks. STUDY DESIGN: Randomized controlled trial; Level of evidence, 1. METHODS: In this 52-week follow-up trial, 100 patients with ankle osteoarthritis were randomized to a PRP group or placebo (saline) group. Patients received 2 intra-articular talocrural injections: at inclusion and after 6 weeks. Patient-reported outcome measures were used to assess pain, function, quality of life, and indirect costs over 52 weeks. RESULTS: Two patients (2%) were lost to follow-up. The adjusted between-group difference for the patient-reported American Orthopaedic Foot & Ankle Society score over 52 weeks was -2 points (95% CI, -5 to 2; P = .31) in favor of the placebo group. No significant between-group differences were observed for any of the secondary outcome measures. CONCLUSION: For patients with ankle osteoarthritis, PRP injections did not improve ankle symptoms and function over 52 weeks compared with placebo injections. REGISTRATION: NTR7261 (Netherlands Trial Register).

ELITE: rationale and design of a longitudinal elite athlete, extreme cardiovascular phenotyping, prospective cohort study.

Introduction: The cardiovascular benefits of physical exercise are well-known. However, vigorous exercise has also been associated with adverse cardiac effects. To improve our understanding of cardiovascular adaptation to exercise versus maladaptation and pathology, the limits of adaptation should be firmly established using state-of-the-art diagnostic modalities. We therefore initiated the Evaluation of Lifetime participation in Intensive Top-level sports and Exercise (ELITE) cohort to investigate the longitudinal (beneficial and pathological) cardiovascular effects of intensive elite sports and exercise. Methods and analysis: ELITE is a prospective, multicentre, longitudinal cohort study. Elite athletes, from the age of sixteen, are recruited in The Netherlands. The primary objective is to determine the association between elite sports and exercise-induced cardiac remodelling, cardiac pathology, and health benefits over time. Secondary objectives include determining and identifying genetic profiles of elite athletes, and how these are associated with cardiac indices. ELITE will collect data from consultations, electrocardiography, echocardiography and cardiac magnetic resonance imaging, and training- and injury data. ELITE will also collect blood for biobanking and cardiogenetics. Follow-up will take place at intervals of two to five years, and after the elite athletes' professional careers have ended. In addition, a subcohort of ELITE has been established to investigate cardiac sequelae following infections associated with myocardial involvement, including SARS-CoV-2. ELITE is a prospective observational study; therefore, analyses will be primarily explorative. Ethics and dissemination: This study has been approved by the Medical Ethics Review Board of the Amsterdam University Medical Centers (NL71682.018.19). The results of the study will be disseminated by publication in peer-reviewed journals (Netherlands Trial Register number: NL9328).

Proximal hamstring tendon avulsions: comparable clinical outcomes of operative and non-operative treatment at 1-year follow-up using a shared decision-making model.

OBJECTIVE: To prospectively evaluate 1-year clinical and radiological outcomes after operative and non-operative treatment of proximal hamstring tendon avulsions. METHODS: Patients with an MRI-confirmed proximal hamstring tendon avulsion were included. Operative or non-operative treatment was selected by a shared decision-making process. The primary outcome was the Perth Hamstring Assessment Tool (PHAT) score. Secondary outcome scores were Proximal Hamstring Injury Questionnaire, EQ-5D-3L, Tegner Activity Scale, return to sports, hamstring flexibility, isometric hamstring strength and MRI findings including proximal continuity. RESULTS: Twenty-six operative and 33 non-operative patients with a median age of 51 (IQR: 37-57) and 49 (IQR: 45-56) years were included. Median time between injury and initial visit was 12 (IQR 6-19) days for operative and 21 (IQR 12-48) days for non-operative patients (p=0.004). Baseline PHAT scores were significantly lower in the operative group (32±16 vs 45±17, p=0.003). There was no difference in mean PHAT score between groups at 1 year follow-up (80±19 vs 80±17, p=0.97). Mean PHAT score improved by 47 (95% CI 39 to 55, p<0.001) after operative and 34 (95% CI 27 to 41, p<0.001) after non-operative treatment. There were no relevant differences in secondary clinical outcome measures. Proximal continuity on MRI was present in 20 (95%, 1 recurrence) operative and 14 (52%, no recurrences) non-operative patients (p=0.008). CONCLUSION: In a shared decision-making model of care, both operative and non-operative treatment of proximal hamstring tendon avulsions resulted in comparable clinical outcome at 1-year follow-up. Operative patients had lower pretreatment PHAT scores but improved substantially to reach comparable PHAT scores as non-operative patients. We recommend using this shared decision model of care until evidence-based indications in favour of either treatment option are available from high-level clinical trials.

Foot Orthoses Enhance the Effectiveness of Exercise, Shockwave, and Ice Therapy in the Management of Medial Tibial Stress Syndrome.

OBJECTIVE: Our aim was to assess the effects of adding arch-support foot-orthoses (ASFO) to a multimodal therapeutic intervention on the perception of pain and improvement of recovery from medial tibial stress syndrome (MTSS) in recreational runners. DESIGN: A prospective randomized controlled trial. SETTING: Sport training and medical centers. PARTICIPANTS: Fifty female recreational runners with MTSS were randomized into 2 groups. INTERVENTIONS: Runners either received ASFO or sham flat noncontoured orthoses. Both groups received a multimodal therapeutic intervention, including ice massage, ankle muscle exercises, and extracorporeal shockwave therapy. MAIN OUTCOME MEASURES: Pain during bone pressure using a numerical Likert scale (0-10), MTSS severity using an MTSS scale, perceived treatment effect using the global rating of change scale, and quality of life using the short Form-36 questionnaire were determined at week 6, 12, and 18. RESULTS: Pain intensity and MTSS severity were lower, and the perceived treatment effect and physical function were better in the ASFO than in the sham flat noncontoured orthoses group at week 6 and week 12. Cohen's dz effect size for between-group differences showed a medium difference. However, arch-support foot-orthoses did not add to the benefits of multimodal therapeutic intervention on pain, MTSS severity and perceived treatment effect at week 18. CONCLUSIONS: Adding ASFO to a therapeutic intervention leads to an earlier diminishment of pain and MTSS severity, and improved PF and perceived therapeutic effects.

Effect of Platelet-Rich Plasma Injections vs Placebo on Ankle Symptoms and Function in Patients With Ankle Osteoarthritis: A Randomized Clinical Trial.

Importance: Approximately 3.4% of adults have ankle (tibiotalar) osteoarthritis and, among younger patients, ankle osteoarthritis is more common than knee and hip osteoarthritis. Few effective nonsurgical interventions exist, but platelet-rich plasma (PRP) injections are widely used, with some evidence of efficacy in knee osteoarthritis. Objective: To determine the effect of PRP injections on symptoms and function in patients with ankle osteoarthritis. Design, Setting, and Participants: A multicenter, block-randomized, double-blinded, placebo-controlled clinical trial performed at 6 sites in the Netherlands that included 100 patients with pain greater than 40 on a visual analog scale (range, 0-100) and tibiotalar joint space narrowing. Enrollment began on August 24, 2018, and follow-up was completed on December 3, 2020. Interventions: Patients were randomly assigned (1:1) to receive 2 ultrasonography-guided intra-articular injections of either PRP (n = 48) or placebo (saline; n = 52). Main Outcomes and Measures: The primary outcome was the validated American Orthopaedic Foot and Ankle Society score (range, 0-100; higher scores indicate less pain and better function; minimal clinically important difference, 12 points) over 26 weeks. Results: Among 100 randomized patients (mean age, 56 years; 45 [45%] women), no patients were lost to follow-up for the primary outcome. Compared with baseline values, the mean American Orthopaedic Foot and Ankle Society score improved by 10 points in the PRP group (from 63 to 73 points [95% CI, 6-14]; P < .001) and 11 points in the placebo group (from 64 to 75 points [95% CI, 7-15]; P < .001). The adjusted between-group difference over 26 weeks was -1 ([95% CI, -6 to 3]; P = .56). One serious adverse event was reported in the placebo group, which was unrelated to the intervention; there were 13 other adverse events in the PRP group and 8 in the placebo group. Conclusions and Relevance: Among patients with ankle osteoarthritis, intra-articular PRP injections, compared with placebo injections, did not significantly improve ankle symptoms and function over 26 weeks. The results of this study do not support the use of PRP injections for ankle osteoarthritis. Trial Registration: Netherlands Trial Register: NTR7261.

Performance and thermoregulation of Dutch Olympic and Paralympic athletes exercising in the heat: Rationale and design of the Thermo Tokyo study: The journal Temperature toolbox.

The environmental conditions during the Tokyo Olympic and Paralympic Games are expected to be challenging, which increases the risk for participating athletes to develop heat-related illnesses and experience performance loss. To allow safe and optimal exercise performance of Dutch elite athletes, the Thermo Tokyo study aimed to determine thermoregulatory responses and performance loss among elite athletes during exercise in the heat, and to identify personal, sports-related, and environmental factors that contribute to the magnitude of these outcomes. For this purpose, Dutch Olympic and Paralympic athletes performed two personalized incremental exercise tests in simulated control (15°C, relative humidity (RH) 50%) and Tokyo (32°C, RH 75%) conditions, during which exercise performance and (thermo)physiological parameters were obtained. Thereafter, athletes were invited for an additional visit to conduct anthropometric, dual-energy X-ray absorptiometry (DXA), and 3D scan measurements. Collected data also served as input for a thermophysiological computer simulation model to estimate the impact of a wider range of environmental conditions on thermoregulatory responses. Findings of this study can be used to inform elite athletes and their coaches on how heat impacts their individual (thermo)physiological responses and, based on these data, advise which personalized countermeasures (i.e. heat acclimation, cooling interventions, rehydration plan) can be taken to allow safe and maximal performance in the challenging environmental conditions of the Tokyo 2020 Olympic and Paralympic Games.

Autologous stem cell therapy in knee osteoarthritis: a systematic review of randomised controlled trials.

OBJECTIVE: Stem cell therapy is increasingly used for knee osteoarthritis (KOA). We aimed to review the evidence of autologous mesenchymal stem cell therapy on pain, function and severity on imaging in KOA. DESIGN: Systematic review of randomised controlled trials (RCTs). ELIGIBILITY CRITERIA: RCTs evaluating autologous mesenchymal stem cell (MSC) therapy on patient-reported outcome measures and disease severity. DATA SOURCES: Seven databases were searched until 31 December 2020. RISK OF BIAS AND DATA SYNTHESIS: Risk of bias was assessed using the ROB V.2. We used Grading of Recommendations Assessment, Development and Evaluation to appraise the certainty of the evidence. Data were synthesised descriptively. RESULTS: Fourteen RCTs were included. A total of 408 patients with KOA received MSC therapy derived from bone marrow, adipose tissue or activated peripheral blood. After 1 year, 19 of 26 (73%) clinical outcome measures improved with MSCs compared with control. In the MSC group, patients improved by 1.8-4.4 points on the Visual Analogue Scale (0-10) and 18-32 points of the Knee Osteoarthritis Outcome Score (0-100). Four studies showed better disease severity on imaging after MSC compared with control at 1 year. Ten of 14 (71%) RCTs were at high risk of bias on all outcomes. No serious adverse events were reported after MSC therapy during a maximum of 4 years follow-up. CONCLUSION: We found a positive effect of autologous MSC therapy compared with control treatments on patient-reported outcome measures, and disease severity. The certainty of this evidence was low to very low. PROSPERO REGISTRATION NUMBER: CRD42019120506.

Incidence of Acute Hamstring Injuries in Soccer: A Systematic Review of 13 Studies Involving More Than 3800 Athletes With 2 Million Sport Exposure Hours.

OBJECTIVE: To estimate the incidence and recurrence rates of acute hamstring injuries in all levels of soccer. DESIGN: Epidemiology systematic review. LITERATURE SEARCH: We searched the PubMed (including MEDLINE), CINAHL, SPORTDiscus, Embase, and Cochrane Central Register of Controlled Trials electronic databases. STUDY SELECTION CRITERIA: We included prospective studies of all levels of adult soccer players that registered acute hamstring injuries and provided a description of incidence of acute hamstring injuries per 1000 playing hours (or available data to calculate this). DATA SYNTHESIS: Due to heterogeneity, we synthesized the data descriptively. RESULTS: Thirteen studies including 3868 players met the inclusion criteria. Two of 13 included studies reported on hamstring injuries in women, and all reported the same in men. The incidence of acute hamstring injury ranged from 0.3 to 0.5 per 1000 exposure hours in women and 0.3 to 1.9 per 1000 exposure hours in men. Hamstring injuries accounted for 5% to 15% of all soccer-related injuries. Hamstring injury recurrence rates ranged from 4% to 68%, depending on the injury definition. Certainty of evidence ranged from moderate to very low. CONCLUSION: The incidence of acute hamstring injury in soccer was 0.3 to 1.9 per 1000 exposure hours. The recurrence rate was 4% to 68%. The strength of the evidence was limited by a lack of methodological rigor, the use of varying definitions for acute hamstring injury, and heterogeneous methods of reporting on acute hamstring injuries. J Orthop Sports Phys Ther 2021;51(1):27-36. Epub 11 Dec 2020. doi:10.2519/jospt.2021.9305.

Dim light, sleep tight, and wake up bright - Sleep optimization in athletes by means of light regulation.

Despite an elevated recovery need, research indicates that athletes often exhibit relatively poor sleep. Timing and consolidation of sleep is driven by the circadian system, which requires periodic light-dark exposure for stable entrainment to the 24-hour day, but is often disturbed due to underexposure to light in the morning (e.g. low-level indoor lighting) and overexposure to light in the evening (e.g. environmental and screen-light). This study examined whether combining fixed sleep schedules with light regulation leads to more consolidated sleep. Morning light exposure was increased using light-emitting goggles, whereas evening light exposure was reduced using amber-lens glasses. Using a within-subject crossover design, twenty-six athletes (14 female, 12 male) were randomly assigned to start the intervention with the light-regulation-week or the no light-regulation-week. Sleep was monitored by means of sleep diaries and actigraphy. Due to low protocol adherence regarding the fixed sleep-wake schedules, two datasets were constructed; one including athletes who kept a strict sleep-wake schedule (N = 8), and one that also included athletes with a more lenient sleep-wake schedule (N = 25). In case of a lenient sleep-wake schedule, light regulation improved self-reported sleep onset latency (Δ SOL = 8 min). This effect was stronger (Δ SOL = 17 min) and complemented by enhanced subjective sleep quality in case of a strict sleep-wake schedule. None of the actigraphy-based estimates differed significantly between conditions. To conclude, light regulation may be considered a potentially effective strategy to improve subjective sleep, but less obtrusive methods should be explored to increase protocol compliance.

Is high soleus muscle activity during the stance phase of the running cycle a potential risk factor for the development of medial tibial stress syndrome? A prospective study.

To assess the impact of lower-leg muscle activity during the stance phase of running on the development of medial tibial stress syndrome (MTSS), in 123 healthy participants (18.2 ± 0.8 years), dynamic and static foot posture, and soleus and tibialis anterior muscle activity during the stance phase of running were measured before a 17-week track- and field-course. After the course, MTSS was identified in 20.5% of the participants. MTSS participants had a higher body mass (ES = 1.13), body mass index (BMI) (ES = 1.31), lower previous vigorous physical activity level (ES = 0.84) and VO2max (ES = 0.61), greater dynamic foot pronation (ES = 0.66), higher soleus peak EMG amplitude during the absorption (ES = 0.60) and propulsion phases (ES = 0.56) of running, and a history of MTSS (OR = 6.38) (p < 0.05). Stepwise logistic regression showed BMI, dynamic foot index, soleus peak EMG amplitude during propulsion, MTSS history and previous vigorous physical activity were predictors of MTSS. The model predicted 96.6% of the healthy participants and 56.5% of the MTSS participants and correctly classified 88.4% of overall cases. Coaches and sports-medicine professionals that screen for injury risk should consider adopting a comprehensive evaluation that includes these parameters.

Effectiveness of an e-health tennis-specific injury prevention programme: randomised controlled trial in adult recreational tennis players.

BACKGROUND: Despite reported injury rates of up to 3 per 1000 hours exposure, there are no evidence-based prevention programmes in tennis. PURPOSE: To evaluate the effectiveness of an e-health prevention programme for reducing tennis injury prevalence. STUDY DESIGN: Two-arm, researcher-blinded randomised controlled trial. METHODS: Adult tennis players of all playing levels were randomised in an unsupervised programme lasting 12 weeks (TennisReady group or control group). The primary outcome was the overall injury prevalence over a 16-week period, measured at 2 weekly intervals with the Oslo Sports and Trauma Research Centre questionnaire. Estimates for the primary outcome and associated 95% CIs were obtained using generalised estimating equation models. Secondary outcome scores included prevalence of substantial injuries, overall incidence, adherence and time-loss injuries. RESULTS: A total of 579 (83%) (TennisReady n=286, control n=293) participants were included in the primary analysis. The mean injury prevalence was 37% (95% CI 33% to 42%) in the TennisReady vs 38% (95% CI 34% to 42%) in the control group (adjusted p-value 0.93). The prevalence of substantial injuries was 11% (95% CI 9% to 14%) in the TennisReady vs 12% (95% CI 9% to 15%) in the control group (p value of 0.79). Analysis of the secondary outcome scores showed no difference between groups. The mean prevalence rates between high (8%) and low (92%) adherent groups were 32% (95% CI 23% to 44%) and 37% (95% CI 33% to 42%), respectively (p value 0.36). CONCLUSION: Providing an unsupervised e-health tennis-specific exercise programme did not reduce the injury rates and should not be implemented. TRIAL REGISTRATION NUMBER: NTR6443.

Oral health among Dutch elite athletes prior to Rio 2016.

OBJECTIVES: Elite athletes are at high risk for poor oral health. A screening program to assess oral health and create dental awareness can improve oral health among elite athletes but has not been performed in the Netherlands before. We summarize the first results from such a screening conducted in Dutch elite athletes of the Nederlands Olympisch Committee*Nederlandse Sport Federatie (NOC*NSF, Dutch Olympic Committee). METHODS: In this cross-sectional study, 800 Dutch athletes eligible for the Olympic and Paralympic Games in Rio de Janeiro 2016 were invited to a costless and voluntary oral examination. The decayed, missing, and filled teeth-index (DMFT), the basic erosive wear examination (BEWE) and the Dutch Periodontal Screening-index (DPSI) were used to evaluate athlete's oral health. Information on sociodemographic variables and sport performance were collected in questionnaires. RESULTS: In total, 116 Dutch elite athletes were included in the study. The median (90%-range) DMFT-score was 3.0 (0.0-16.0), the median BEWE-score was 2.0 (0.0-10.0), and the mean± SD DPSI-score was 2.0 ± 0.73. Oral health-related quality of life was generally high, although only 28.2% of the athletes reported never having problems with their dentition or mouth. In 43% of the athlete's clinical findings were reported which needed a direct referral to the general dentist. CONCLUSION: Oral health in this subsample of Dutch elite athletes was surprisingly affected as almost half of them needed dental treatment. Further research is needed to allow conclusions about oral health in Dutch elite athletes more broadly. However, regular screening of oral health incorporated into the general preventive health care of elite athletes is necessary to ensure athletes are fully healthy during competitions like the Olympic and Paralympic Games.

Microcrack-associated bone remodeling is rarely observed in biopsies from athletes with medial tibial stress syndrome.

The pathology of medial tibial stress syndrome (MTSS) is unknown. Studies suggest that MTSS is a bony overload injury, but histological evidence is sparse. The presence of microdamage, and its potential association with targeted remodeling, could provide evidence for the pathogenesis of MTSS. Understanding the pathology underlying MTSS could contribute to effective preventative and therapeutic interventions for MTSS. Our aim was to retrospectively evaluate biopsies, previously taken from the painful area in athletes with MTSS, for the presence of linear microcracks, diffuse microdamage and remodeling. Biopsies, previously taken from athletes with MTSS, were evaluated at the Department of Anatomy and Cell Biology at the Indiana University. After preparing the specimens by en bloc staining, one investigator evaluated the presence of linear microcracks, diffuse microdamage and remodeling in the specimens. A total of six biopsies were evaluated for the presence of microdamage and remodeling. Linear microcracks were found in 4 out of 6 biopsies. Cracking in one of these specimens was artefactual due to the biopsy procedure. No diffuse microdamage was seen in any of the specimens, and only one potential remodeling front in association with the microcracks. We found only linear microcracks in vivo in biopsies taken from the painful area in 50% of the athletes with MTSS, consistent with the relationship between linear cracks and fatigue-associated overloading of bone. The nearly universal absence of a repair reaction was notable. This suggests that unrepaired microdamage accumulation may underlie the pathophysiological basis for MTSS in athletes.

Effects of Natural Between-Days Variation in Sleep on Elite Athletes' Psychomotor Vigilance and Sport-Specific Measures of Performance.

Performance capacity in athletes depends on the ability to recover from past exercise. While evidence suggests that athletic performance decreases following (partial) sleep deprivation and increases following sleep extension, it is unclear to which extent natural variation in sleep impacts performance. Sleep quantity and, for the first time, sleep stages were assessed among 98 elite athletes on three non-consecutive nights within a 7-day monitoring period, along with performance tests that were taken on standardized times each following morning. Performance assessment included psychomotor performance (10-minute psychomotor vigilance task) and sport-specific tests of fine (e.g., accuracy) and gross motor skills (e.g., endurance, power). Mixed-effects models were employed to assess the effect of sleep quantity (total sleep time (TST), sleep onset latency (SOL), wake after sleep onset, sleep efficiency) and sleep stage duration (light, deep, REM) on performance. Average TST was 7:30 ± 1:05 hours, with a mean variation of 57 minutes across days. Longer TSTs were associated with faster reaction times (p = 0.04). Analyses indicated small and inconsistent effects of sleep quantity (TST, SOL) and sleep staging (light sleep) on gross motor performance, and no effects on fine motor skill performance. Results indicate that natural variation in sleep quantity impacts psychomotor vigilance to a greater extent than athletic performance. Small or absent effects can be a consequence of the rather small variation in non-manipulated sleep. It is suggested that one night of compromised sleep may not be immediately problematic, but that more extreme sleep loss or accumulated sleep debt may have more severe consequences.

Intramuscular tendon injury is not associated with an increased hamstring reinjury rate within 12 months after return to play.

BACKGROUND: Acute hamstring injury that includes intramuscular tendon injury has been suggested to be associated with increased reinjury risk. These observations were based on a relatively small number of retrospectively analysed cases. OBJECTIVE: To determine whether intramuscular tendon injury is associated with higher reinjury rates in acute hamstring injury. METHODS: MRIs of 165 athletes with an acute hamstring injury were obtained within 5 days of injury. Treatment consisted of a standardised criteria-based rehabilitation programme. Standardised MRI parameters and intramuscular tendon injury, the latter subdivided into tendon disruption and waviness, were scored. We prospectively recorded reinjuries, defined as acute onset of posterior thigh pain in the same leg within 12 months after return to play. RESULTS: Participants were predominantly football players (72%). Sixty-four of 165 (39%) participants had an index injury with intramuscular hamstring tendon disruption, and waviness was present in 37 (22%). In total, there were 32 (19%) reinjuries. There was no significant difference (HR: 1.05, 95% CI 0.52 to 2.12, P=0.898) in reinjury rate between index injuries with intramuscular tendon disruption (n=13, 20%) and without tendon disruption (n=19, 20%). There was no significant difference in reinjury rate (X²(1)=0.031, P=0.861) between index injuries with presence of waviness (n=7, 19%) and without presence of waviness (n=25, 20%). CONCLUSION: In athletes with an acute hamstring injury, intramuscular tendon injury was not associated with an increased reinjury rate within 12 months after return to play.

Train hard, sleep well? Perceived training load, sleep quantity and sleep stage distribution in elite level athletes.

OBJECTIVES: Sleep is essential for recovery and performance in elite athletes. While it is generally assumed that exercise benefits sleep, high training load may jeopardize sleep and hence limit adequate recovery. To examine this, the current study assessed objective sleep quantity and sleep stage distributions in elite athletes and calculated their association with perceived training load. DESIGN: Mixed-methods. METHODS: Perceived training load, actigraphy and one-channel EEG recordings were collected among 98 elite athletes during 7 consecutive days of regular training. RESULTS: Actigraphy revealed total sleep durations of 7:50±1:08h, sleep onset latencies of 13±15min, wake after sleep onset of 33±17min and sleep efficiencies of 88±5%. Distribution of sleep stages indicated 51±9% light sleep, 21±8% deep sleep, and 27±7% REM sleep. On average, perceived training load was 5.40±2.50 (scale 1-10), showing large daily variability. Mixed-effects models revealed no alteration in sleep quantity or sleep stage distributions as a function of day-to-day variation in preceding training load (all p's>.05). CONCLUSIONS: Results indicate healthy sleep durations, but elevated wake after sleep onset, suggesting a potential need for sleep optimization. Large proportions of deep sleep potentially reflect an elevated recovery need. With sleep quantity and sleep stage distributions remaining irresponsive to variations in perceived training load, it is questionable whether athletes' current sleep provides sufficient recovery after strenuous exercise.

Successful return to play following adductor longus proximal tendon rupture in professional soccer without re-injury at 12 months: A case report.

Treatment of total ruptures of adductor longus is challenging in professional sports. Time for return to pre-injury level as well as re-injury rates are of concern and surgical and conservative treatment approaches are debated; yet no consensus approach described for professional athletes. We present a case of a professional soccer player who experienced a rupture in his left adductor longus proximal tendon during a game and was treated conservatively. This case was followed-up during clinical assessment, imaging and strength testing until and after return to play. Primary outcome measure was the return to standard play condition at his pre-injury level without any functional deficits, measured by isokinetic testing. Second outcome measure was the recurrence. No recurrence was observed during the first year of follow-up. Total ruptures are very challenging for both the physician and the player to make a quick decision due to minimal or lack of pain. Functional outcomes are almost identical although operative treatments need longer time to return to play. This case report adds another example to the literature of a successful return to play after non-operative treatment of adductor longus rupture at elite level soccer.

Can a Clinical Examination Demonstrate Intramuscular Tendon Involvement in Acute Hamstring Injuries?

BACKGROUND: Involvement of the intramuscular (central) tendon in acute hamstring injuries, as detected on magnetic resonance imaging (MRI), may prolong recovery times. To date, it is unclear whether hamstring injuries exhibiting intramuscular tendon involvement can be identified though routine clinical examinations that assess flexibility and strength. PURPOSE: To test whether MRI-detected intramuscular tendon involvement could be identified by a clinical assessment of muscle strength and flexibility. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: Participants were drawn from a multicenter randomized controlled trial on the effect of platelet-rich plasma in acute hamstring injuries. Clinical parameters assessed within 5 days of injury were active knee extension and passive straight-leg raise for hamstring flexibility and isometric knee flexion force with 15° and 90° of knee flexion. Also, 1.5-T MRI of the thigh was performed within 5 days of injury and was evaluated for the presence of different types of intramuscular tendon involvement. One-way analysis of variance was used to determine whether clinical parameters could discriminate injuries with intramuscular tendon involvement from those without such involvement. RESULTS: A total of 74 acute hamstring injuries were included, with 52 (70.3%) injuries affecting the myotendinous junction. Injuries exhibiting intramuscular tendon discontinuity on MRI had an increased mean absolute flexibility deficit for active knee extension (20.4° ± 14.9° vs 10.7° ± 9.0°, respectively; P = .006) and decreased mean strength at 15° (62.2 ± 26.7 N vs 76.6 ± 22.5 N, respectively; P = .05) compared with injuries without intramuscular tendon discontinuity. Flexibility and strength showed major overlap and variance among injuries with and without intramuscular tendon involvement. CONCLUSION: Hamstring flexibility and strength cannot be used to discriminate the presence of intramuscular tendon involvement.