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Overuse injuries, which have a high prevalence in sport, are suggested to result in different affective responses in comparison to traumatic injuries. Affects may also reciprocally act as risk factors for overuse injury. The aim of this study was to examine the associations between overuse injury and affects within a longitudinal follow‐up design. Competitive athletes (N = 149) of various sports and levels of competition completed the Positive and Negative Affect Schedule (PANAS) and the Oslo Sports Trauma Research Centre Overuse injury questionnaire (OSTRC‐O) once a week over 10 consecutive weeks. Bivariate unconditional latent curve model analyses with structured residuals were performed to evaluate the associations within and across weeks between OSTRC‐O severity score and affects. Results indicated that OSTRC‐O severity score and positive affects (PA) had a statistically significant negative within‐week relation (r = −24.51, 95% CI = [−33.9, −15.1], p < 0.001). Higher scores of overuse injury were significantly related to lower levels of PA across weeks (ß = −0.02, 95% CI = [−0.04, −0.001], p = 0.044), while the reciprocal effect of PA on overuse injury was not significant (ß = −0.13, 95% CI = [−0.52, 0.26], p = 0.51). No statistically significant association was observed between OSTRC‐O severity score and negative affects, neither within nor across weeks. Our findings suggest that overuse injury may have adverse psychological consequences on the long run through lessened PA and address the need for providing sustainable psychological support focusing upon such PA when working with athletes experiencing overuse injury. [ABSTRACT FROM AUTHOR]

Objective: To explore how sports injury epidemiological outcomes (i.e., prevalence, average prevalence, incidence, burden, and time to first injury) vary depending on the response rates to a weekly online self‐reported questionnaire for athletes. Methods: Weekly information on athletics injuries and exposure from 391 athletics (track and field) athletes was prospectively collected over 39 weeks (control group of the PREVATHLE randomized controlled trial) using an online self‐reported questionnaire. The data were used to calculate sports injury epidemiological outcomes (i.e., prevalence, average prevalence, incidence, burden, and time to first injury) for sub‐groups with different minimum individual athletes' response rates (i.e., from at least 100%, at least 97%, at least 95%, ... to at least 0% response rate). We then calculated the relative variation between each sub‐group and the sub‐group with a 100% response rate as a reference. A substantial variation was considered when the relative variation was greater than one SD or 95% CI of the respective epidemiological outcome calculated in the sub‐group with a 100% response rate. Results: Of 15 249 expected weekly questionnaires, 7209 were completed and returned, resulting in an overall response rate of 47.3%. The individual athletes' response rates ranged from 0% (n = 51) to 100% (n = 100). The prevalence, average weekly prevalence, and time to first injury only varied substantially for the sub‐groups below a 5%, 10% and 18% minimum individual response rate, respectively. The incidence and injury burden showed substantial variations for all sub‐groups with a response rate below 100%. Conclusions: Epidemiological outcomes varied depending on the minimum individual athletes' response rate, with injury prevalence, average weekly prevalence, and time to first injury varying less than injury incidence and injury burden. This highlights the need to take into account the individual response rate when calculating epidemiological outcomes, and determining the optimal study‐specific cut‐offs of the minimum individual response rate needed. [ABSTRACT FROM AUTHOR]

This study aimed to explore how stakeholders in athletics perceive the relevance of injury prevention, determine their communication preferences, and describe their expectations regarding injury prevention. We conducted a cross-sectional study using an exploratory online survey with high-level athletes (i. e. listed by the French ministry of sports), non-high-level athletes (i. e. all competitive level except high-level athletes), coaches, and health professionals licensed with the French Federation of Athletics. The survey was composed of three parts regarding stakeholder's characteristics (4 questions), perceived relevance (2 questions), communication preferences and expectations (3 questions) towards injury prevention. There were 2,864 responders to the survey. Almost all responders found that injury prevention is relevant (97.7% [95% CI 97.0% to 98.2%]), without any significant differences in the distribution between stakeholders' age, experience and sex (p >0.05). About three-quarters of the stakeholders preferred to find injury prevention information on a website (77.4%) without significant differences between stakeholders' categories (p >0.05); other media to find injury prevention information was chosen by less than 50% of responders. Expectations about injury prevention were mainly explanations, advice and tips about injury knowledge, management and prevention, based on expert opinion and/or scientific research. In conclusion, these results confirm that injury prevention is a challenge shared by numerous stakeholders in athletics, within France, and provide some orientation on how and what information to disseminate to these stakeholders. [ABSTRACT FROM AUTHOR]

Context: Isokinetic assessment of shoulder internal- (IR) and external-rotator (ER) strength is commonly used with many different postures (sitting, standing, or supine) and shoulder positions (frontal or scapular plane with 45° or 90° of abduction). Objective: To conduct a systematic review to determine the influence of position on the intersession reliability of the assessment of IR and ER isokinetic strength, to identify the most reliable position, and to determine which isokinetic variable appears to be most stable in intersession reliability. Evidence Acquisition: A systematic literature search through MEDLINE and Pascal Biomed databases was performed in October 2009. Criteria for inclusion were that studies be written in English or French, describe the isokinetic evaluation methods, and describe statistical analysis. Evidence Synthesis: Sixteen studies meeting the inclusion criteria were included. Variable reliability of ER and IR peak torque (PT) were generally reported for all assessment positions; intraclass correlation coefficients were .44-.98 in the seated position with 45° of shoulder abduction, .09-.77 in the seated position with 90° of shoulder abduction, .86-.99 (coefficient of variation: 7.5-29.8%) in the supine position with 90° of shoulder abduction, .82-.84 in the supine position with 45° of shoulder abduction, and .75-.94 in standing. The ER:IR ratio reliability was low for all positions. Conclusions: The seated position with 45° of shoulder abduction in the scapular plane seemed the most reliable for IR and ER strength assessment. The standing position or a shoulder posture with 90° of shoulder abduction or in the frontal plane must be used with caution given the low reliability for peak torque. Good reliability of ER and IR PT was generally reported, but ER:IR ratio reliability was low. [ABSTRACT FROM AUTHOR]

Context: Isokinetic assessment of shoulder internal- (IR) and external-rotator (ER) strength is commonly used with many different postures (sitting, standing, or supine) and shoulder positions (frontal or scapular plane with 45° or 90° of abduction). Objective: To conduct a systematic review to determine the influence of position on the intersession reliability of the assessment of IR and ER isokinetic strength, to identify the most reliable position, and to determine which isokinetic variable appears to be most stable in intersession reliability. Evidence Acquisition: A systematic literature search through MEDLINE and Pascal Biomed databases was performed in October 2009. Criteria for inclusion were that studies be written in English or French, describe the isokinetic evaluation methods, and describe statistical analysis. Evidence Synthesis: Sixteen studies meeting the inclusion criteria were included. Variable reliability of ER and IR peak torque (PT) were generally reported for all assessment positions; intraclass correlation coefficients were .44-.98 in the seated position with 45° of shoulder abduction, .09-.77 in the seated position with 90° of shoulder abduction, .86-.99 (coefficient of variation: 7.5-29.8%) in the supine position with 90° of shoulder abduction, .82-.84 in the supine position with 45° of shoulder abduction, and .75-.94 in standing. The ER:IR ratio reliability was low for all positions. Conclusions: The seated position with 45° of shoulder abduction in the scapular plane seemed the most reliable for IR and ER strength assessment. The standing position or a shoulder posture with 90° of shoulder abduction or in the frontal plane must be used with caution given the low reliability for peak torque. Good reliability of ER and IR PT was generally reported, but ER:IR ratio reliability was low. [ABSTRACT FROM AUTHOR]

Résumé: Un guide de pratique à l'attention des médecins généralistes devant prendre en charge des adolescents présentant une scoliose idiopathique autour de la pratique sportive a été pensé au travers d'une revue de la littérature et d'une enquête de pratique. Nous avons détaillé plusieurs aspects à prendre en compte dans ce questionnement : le sport en général, le sport à l'école, le sport pendant le traitement par corset ont été traités dans la première partie de cet article. La seconde partie aborde les compétitions et le retour au sport après prise en charge chirurgicale. A practice guide for general practitioners who have to manage adolescents with idiopathic scoliosis on the topic of sports practice was designed through a review of the literature and a practice survey. We have detailed several aspects to be taken into account in this questioning: sport in general, sport at school, sport during corset treatment were dealt with in article 1; this article deals with competitions and the return to sport after surgical treatment. [ABSTRACT FROM AUTHOR]

Background Injury incidence has been reported for international athletics championships from 2007 to 2012. However, it is unclear whether male or female athletes differ in risk and/or characteristics of injuries. Objective To compare the incidences and characteristics of injuries that occurred during international athletics championships between female and male athletes. Methods The national medical team and the local organising committee physicians reported all injuries daily on a standardised injury report form during 14 international championships from 2007 to 2014. Relative risks (RR) of injury, 95% CI and magnitude thresholds were calculated. Results The rate of injuries per 1000 registered athletes was significantly higher in male (110.3±6.8) than in female (88.5±6.7) athletes (RR=1.25; 95% CI 1.13 to 1.37, small effect size). Male athletes incurred significantly more injuries in the thigh (RR=1.64; 95% CI 1.32 to 2.05, small), lower leg (RR=1.36; 95% CI 1.05 to 1.75, small) and hip/groin injuries (RR=2.26; 95% CI 1.31 to 3.88, moderate), more muscle strains (RR=1.64; 95% CI 1.33 to 2.04, small), cramps (RR=1.81; 95% CI 1.35 to 2.43, small), and especially more thigh strains (RR=1.66; 95% CI 1.25 to 2.19, small), but fewer stress fractures (RR=0.32; 95% CI 0.12 to 0.81, moderate) than female athletes. A higher injury risk of male than of female athletes was observed in sprints (RR=1.32; 95% CI 1.06 to 1.66, small), middle distance runs (RR=1.48; 95% CI 1.06 to 2.06, small), race walks (RR=2.55; 95% CI 1.27 to 5.10, moderate) and jumps (RR=2.13; 95% CI 1.53 to 2.97, moderate). No sex difference was found for cause and severity of injury. Conclusions Injury risk during international athletics championships differed between female and male athletes for location, type and event groups. Injury prevention strategies should be sex-specific, regarding the differences in injury location and type. [ABSTRACT FROM AUTHOR]

Objective: To further analyze newly incurred injuries and illnesses (I&Is) during Athletics International Championships to discuss risk factors. Design: Prospective recording of newly occurred injuries and illnesses. Setting: The 2012 European Athletics (EA) Championships in Helsinki, Finland. Participants: National team and local organizing committee physicians and physiotherapists and 1342 registered athletes. Main Outcome Measures: Incidence and characteristics o f new injuries and illnesses. Results: Ninety-three percent of athletes were covered by medical teams, with a response rate of 91%. One hundred thirty-three injuries were reported (incidence of 98.4 injuries per 1000 registered athletes). Sixty-two injuries (47%) resulted in time loss from sport. The most common diagnosis was hamstring strain (11.4% of injuries and 21% of time-loss injuries). Injury risk was higher in males and increased with age. The highest incidences of injuries were found in combined events and middle-and long-distance events. Twenty-seven illnesses were reported (4.0 illnesses per 1000 athlete days). The most common diagnoses were upper respiratory tract infection (33.3%) and gastroenteritis/diarrhea (25.9%). Conclusions: During outdoor EA Championships, injury and illness incidences were slightly lower and injury characteristics were comparable with those during outdoor World Athletics Championships. During elite athletics Championships, gender (male), age (older than 30 years), finals, and some events (combined events and middle- and long-distance races) seem to be injury risk factors. Illness risk factors remain unclear. As in previous recommendations, preventive interventions should focus on overuse injuries, hamstring strains, and adequate rehabilitation o f previous injuries, decreasing risk o f infectious diseases transmission, appropriate event scheduling, sports clothes, and heat acclimatization. [ABSTRACT FROM AUTHOR]

• To individualise injury risk reduction measures could help to better match athlete's individual characteristics and should thus improve their effectiveness. • To individualise injury risk reduction measures could help to improve athlete adherence into such measures and consequently their effectiveness. • This maximised individualised approach is proposed to be used whatever the sport (i.e., individual and teams sports) in both scientific studies and real-world settings, with an end-user centred approach (especially athlete-centred approach) and a co-construction of the injury risk reduction measures with all stakeholders. [ABSTRACT FROM AUTHOR]

BACKGROUND: Adaptations to Internal (IR) and external (ER) rotator shoulder muscles improving overhead throwing kinematics could lead to muscular strength imbalances and be considered an intrinsic risk factor for shoulder injury, as well as modified shoulder range of motion (RoM). OBJECTIVE: To establish profiles of internal and external rotation RoM and isokinetic IR and ER strength in adolescent- and national-level javelin throwers. METHODS: Fourteen healthy subjects were included in this preliminary cross-sectional study, 7 javelin throwers (JTG) and 7 nonathletes (CG). Passive internal and external rotation RoM were measured at 90° of shoulder abduction. Isokinetic strength of dominant and non-dominant IR and ER was evaluated during concentric (60, 120 and 240°/s) and eccentric (60°/s) contractions by Con-Trex® dynamometer with the subject in a seated position with 45° of shoulder abduction in the scapular plane. RESULTS: We reported significantly lower internal rotation and significantly higher external rotation RoM in JTG than in CG. Concentric and eccentric IR and ER strength were significantly higher for the dominant shoulder side in JTG (P < 0.05), without significant differences in ER/IR ratios. CONCLUSIONS: The main finding of this preliminary study confirmed static and dynamic shoulder stabilizer adaptations due to javelin throw practice in a population of adolescent- and national-level javelin throwers. [ABSTRACT FROM AUTHOR]

BACKGROUND: Adaptations to Internal (IR) and external (ER) rotator shoulder muscles improving overhead throwing kinematics could lead to muscular strength imbalances and be considered an intrinsic risk factor for shoulder injury, as well as modified shoulder range of motion (RoM). OBJECTIVE: To establish profiles of internal and external rotation RoM and isokinetic IR and ER strength in adolescent- and national-level javelin throwers. METHODS: Fourteen healthy subjects were included in this preliminary cross-sectional study, 7 javelin throwers (JTG) and 7 nonathletes (CG). Passive internal and external rotation RoM were measured at 90° of shoulder abduction. Isokinetic strength of dominant and non-dominant IR and ER was evaluated during concentric (60, 120 and 240°/s) and eccentric (60°/s) contractions by Con-Trex® dynamometer with the subject in a seated position with 45° of shoulder abduction in the scapular plane. RESULTS: We reported significantly lower internal rotation and significantly higher external rotation RoM in JTG than in CG. Concentric and eccentric IR and ER strength were significantly higher for the dominant shoulder side in JTG (P < 0.05), without significant differences in ER/IR ratios. CONCLUSIONS: The main finding of this preliminary study confirmed static and dynamic shoulder stabilizer adaptations due to javelin throw practice in a population of adolescent- and national-level javelin throwers. [ABSTRACT FROM AUTHOR]

Given the important role of the shoulder sensorimotor system in shoulder stability, its assessment appears of interest. Force platform monitoring of centre of pressure ( CoP) in upper-limb weight-bearing positions is of interest as it allows integration of all aspects of shoulder sensorimotor control. This study aimed to determine the feasibility and reliability of shoulder sensorimotor control assessment by force platform. Forty-five healthy subjects performed two sessions of CoP measurement using Win- Posturo® Medicapteurs force platform in an upper-limb weight-bearing position with the lower limbs resting on a table to either the anterior superior iliac spines ( P1) or upper patellar poles ( P2). Four different conditions were tested in each position in random order: eyes open or eyes closed with trunk supported by both hands and eyes open with trunk supported on the dominant or non-dominant side. P1 reliability values were globally moderate to high for CoP length, CoP velocity and CoP standard deviation ( SD), standard error of measurement ranged from 6·0% to 26·5%, except for CoP area. P2 reliability values were globally low and not clinically acceptable. Our results suggest that shoulder sensorimotor control assessment by force platform is feasible and has good reliability in upper-limb weight-bearing positions when the lower limbs are resting on a table to the anterior superior iliac spines. CoP length, CoP velocity and CoP SD velocity appear to be the most reliable variables. [ABSTRACT FROM AUTHOR]

Objective To determine the incidence and characteristics of newly incurred injuries and illnesses during international Athletics Championships, by improving the medical surveillance coverage, in order to determine future prevention strategies. Design Prospective recording of newly occurred injuries and illnesses. Setting 13th International Association of Athletics Federations World Championships in Athletics 2011 in Daegu, Korea. Participants National team and Local Organising Committee physicians; and 1851 registered athletes. Main outcome measures Incidence and characteristics of newly incurred injuries and illnesses. Results 82% of athletes were covered by medical teams participating with a response rate of 94%. A total of 249 injuries were reported, representing an incidence of 134.5 injuries per 1000 registered athletes, and 119 (48%) resulted in time loss from sport. A total of 185 injuries affected the lower limb (74%). Hamstring strain was the main diagnosis and 67% resulted in absence from sport. Overuse (n=148; 59%) was the predominant cause. A total of 126 illnesses were reported, signifying an incidence of 68.1 per 1000 registered athletes. Upper respiratory tract infection was the most common reported diagnosis (18%), followed by exercise- induced dehydration (12%), and gastroenteritis/diarrhoea (10%). The highest incidences of injuries were found in combined events and middle and long-distance events, and of illness in race walking events. Conclusion During elite Athletics World Championships, 135 injuries, 60 time-loss injuries and 68 illnesses per 1000 registered athletes were reported. Higher risks of injuries were found in combined events and long-distance runs. Preventive interventions should focus on overuse injuries and hamstring strains, decreasing the risk of transmission of infectious diseases, appropriate event scheduling and heat acclimatisation. [ABSTRACT FROM AUTHOR]

The article offers information on the study conducted by the authors related to relation between sprint performance and technical ability to produce net positive horizontal force. It states that 12 males without any musculoskeletal injury or pain participated in the study. It mentions that one week before the experiment, they took a session in which they treadmill sprints until they got comfortable with the required running technique. It highlights that 100 meters (m) sprints were performed in which performance was measutred using a radar Stalker ATS System. It reports that ratio of forces (RF) speed relations were linear for all participants. It informs that force application technique is a determinant factor for 100 m sprint performance.

Background: In track and field, the load of impact, the coordination and the constraints on the ankle could result in adaptations of the ankle dynamic stabilization. These constraints could play a strengthening role and increase invertor and evertor strength also after a previous history of lateral ankle sprain. Objective: To compare the ankle invertor and evertor isokinetic strength in track and field athletes (i) with functional ankle instability (FAI), (ii) with history of lateral ankle sprain but without functional ankle instability, and (iii) without any history of lateral ankle sprain. Methods: Twenty-five track and field athletes (5 female and 20 male, 22 ± 5 years) were included in this cross-sectional controlled study, and divided into 3 groups for comparison: (i) athletes with FAI, (ii) athletes with a previous history of lateral ankle sprain, and (iii) a control group of healthy athletes. The dominant side ankle invertor and evertor isokinetic strength were evaluated concentrically at 120 and 30°/s while the evertor strength was also tested eccentrically at 30°/s. Results: No significant differences were indicated between the muscle strength of the three groups, except for the concentric evertor peak torque and the evertor-to-invertor ratio (EIR) at 30°/s (P < 0.05). The concentric evertor peak torque and EIR at 30°/s were significantly lower in the group of athletes with a previous history of ankle sprain than in the control group (P <0.05). Conclusion: Functional ankle instability and/or history of lateral ankle sprain in track and field athletes were not associated with strength weakness of the invertor or evertor muscles. However, as the EIRs were higher than 1.0 for the healthy track and field athletes and those with FAI, it is suggested that the track and field constraints result in adaptations of the ankle dynamic stabilization and then influence invertor and evertor strength balance. [ABSTRACT FROM AUTHOR]

Background: Although rotator-cuff muscle contraction plays an important role in stabilizing the glenohumeral joint, little is known about the role of these muscles in the pathophysiology of recurrent anterior instability. We intended to analyze the association between isokinetic internal rotator and external rotator muscle strength and glenohumeral joint instability in patients with recurrent anterior instability that was not previously treated surgically. Methods: We enrolled thirty-seven patients with unilateral recurrent anterior posttraumatic shoulder dislocation and eleven healthy non-athletic subjects in this controlled study. The association between internal rotator and external rotator strength and shoulder instability was analyzed by side-to-side comparisons and comparisons with a control group. Isokinetic internal rotator and external rotator strength was evaluated with a Con-Trex dynamometer, with the subject seated and the shoulder abducted 45° in the scapular plane. Tests were performed at 180°/s, 120°/s, and 60°/s in concentric mode for both sides. Peak torque normalized to body weight and external rotator to internal rotator ratio were calculated for each angular velocity. Clinical and isokinetic evaluation was done by the same rehabilitation physician. Results: The association between shoulder instability and internal rotator and external rotator strength was associated with side-to-side differences (p < 0.05). Compared with a control group, strength values were lower on the pathological shoulder side of the patients with shoulder instability than on the healthy contralateral shoulder of control subjects at 180°/s and 120°/s (p < 0.05). The side-to-side differences were increased when the nondominant upper-extremity side was involved and were decreased when the dominant side was involved. There was no association between glenohumeral joint instability and external rotator to internal rotator ratio. Conclusions: Internal rotator and external rotator weakness was associated with recurrent anterior instability, and side-to-side differences depended on the side of hand dominance. Use of a control group may help in the analysis of the influence of constraints on shoulder strength. Further prospective studies are necessary to determine whether the weakness is a cause or an effect of the instability. [ABSTRACT FROM AUTHOR]

Background: Although there have been many studies on isokinetic shoulder exercises in evaluation and rehabilitation programs, the cardiovascular and metabolic responses of those modes of muscle strength exercises have been poorly investigated. Objective: To analyze cardiovascular and metabolic responses during a standardized test used to study the internal (IR) and external (ER) rotators maximal isokinetic strength. Methods: Four days after an incremental exercise test on cycle ergometer, ten healthy subjects performed an isokinetic shoulder strength evaluation with cardiovascular (Heart rate, HR) and metabolic gas exchange (&Vdot;O_{2}) analysis. The IR and ER isokinetic strength, measured in seated position with 45° of shoulder abduction in scapular plane, was evaluated concentrically at 60, 120 and 240°/s and eccentrically at 60°/s, for both shoulder sides. An endurance test with 30 repetitions at 240°/s was performed at the end of each shoulder side testing. Results: There was a significant increase of mean HR with isokinetic exercise (P< 0.05). Increases of HR was 42–71% over the resting values. During endurance testing, increases of HR was 77–105% over the resting values, and corresponded to 85–86% of the maximal HR during incremental test. Increase of &Vdot;O_{2} during isokinetic exercises was from 6–11 ml/min/kg to 20–43 ml/min/kg. Conclusion: This study performed significant cardiovascular and metabolic responses to isokinetic exercise of rotators shoulder muscles. A warm-up should be performed before maximal high-intensity isokinetic shoulder testing. Our results indicated that observation and supervision are important during testing and/or training sessions, especially in subjects with risk for cardiovascular disorders. [ABSTRACT FROM AUTHOR]

Objective: To study the influence of gravitational correction on the internal (IR) and external rotators (ER) shoulder strength. Methods: The IR and ER isokinetic strength, measured in 30° scapation, was evaluated concentrically at 60 and 240°/s and eccentrically at 60°/s in 33 healthy volunteers. Strength scores were expressed either by incorporating gravitational correction (GC) or without it. Results: With GC, IR strength was significantly lower and ER strength significantly higher than without incorporation of this procedure. Conclusion: The GC procedure has a significant influence on IR and ER strength and should be incorporated when strength deficits of the rotator cuff are expected. [ABSTRACT FROM AUTHOR]

Despite exercise‐based injury prevention programs (EIPPs) being widely researched and used, several randomized controlled trials (RCTs) have failed to show their protective effect on injury risk. This is potentially due to underappreciating the EIPP dose–response relationship, by not controlling the analysis for the injuries sustained during the early EIPP implementation period, before the EIPP becomes efficacious. To determine the dose–response relationship of EIPP by controlling for the effects of injuries sustained before it became efficacious. We conducted a secondary analysis of an RCT analyzing the EIPP efficacy in athletics over a 39‐week follow‐up on 840 athletes, by including only those with 100% response rate. We controlled the statistical analyses for a range of lengths of early EIPP implementation period by either excluding the athletes with early injuries (i.e., exclusion approach) or adjusting for the early injuries' effects (i.e., inclusion approach). We estimated the EIPP's dose–response relationship by measuring the EIPP's effect at each length of the controlled period. When we considered no early controlled period, the EIPP showed no effect (OR = 0.85 [95% CI: 0.67–1.09]; p = 0.209). However, both exclusion and inclusion approaches showed that the EIPP effect increased significantly after 5–6 weeks of controlled period. This relationship plateaued at 7–12 weeks of controlled period, peaking at 10 weeks with the exclusion approach (OR = 0.28 [95% CI: 0.16–0.48]; p < 0.001), and 7 weeks with the inclusion approach (OR = 0.37 [95% CI: 0.25–0.55]; p < 0.001). Acknowledging the dose–response relationship of EIPPs could help researchers to design and analyze RCTs and practitioners to plan EIPP implementation timely. Trial Registration: ClinicalTrials.gov Identifier: NCT03307434 [ABSTRACT FROM AUTHOR]

The aim was to determine the respective influences of sprinting maximal power output (PHmax) and mechanical Force‐velocity (F‐v) profile (ie, ratio between horizontal force production capacities at low and high velocities) on sprint acceleration performance. A macroscopic biomechanical model using an inverse dynamics approach applied to the athlete's center of mass during running acceleration was developed to express the time to cover a given distance as a mathematical function of PHmax and F‐v profile. Simulations showed that sprint acceleration performance depends mainly on PHmax, but also on the F‐v profile, with the existence of an individual optimal F‐v profile corresponding, for a given PHmax, to the best balance between force production capacities at low and high velocities. This individual optimal profile depends on PHmax and sprint distance: the lower the sprint distance, the more the optimal F‐v profile is oriented to force capabilities and vice versa. When applying this model to the data of 231 athletes from very different sports, differences between optimal and actual F‐v profile were observed and depend more on the variability in the optimal F‐v profile between sprint distances than on the interindividual variability in F‐v profiles. For a given sprint distance, acceleration performance (<30 m) mainly depends on PHmax and slightly on the difference between optimal and actual F‐v profile, the weight of each variable changing with sprint distance. Sprint acceleration performance is determined by both maximization of the horizontal power output capabilities and the optimization of the mechanical F‐v profile of sprint propulsion. [ABSTRACT FROM AUTHOR]

The primary objective of this study was to investigate the relationship between metatarsophalangeal joint (MTPj) flexion torque and sprint acceleration, cutting and jumping performance, and kinetics. A secondary aim was to explore this relationship when MTP flexion strength was associated with other foot and lower limb neuromuscular outputs. After an initial MTPj flexion torque assessment using a custom-built dynamometer, 52 high-level athletes performed the following tasks on a force platform system: maximal sprint acceleration, 90-degree cutting, vertical and horizontal jumps, and foot-ankle hops. Their foot posture, foot passive stiffness and foot-ankle reactive strength were assessed using the Foot Posture Index, the Arch Height Index Measurement System and the Foot-Ankle Rebound Jump Test. Ankle plantarflexion and knee extension isometric torque were assessed using an isokinetic dynamometer. During maximal speed sprinting, multiple linear regressions suggested a major contribution of MTPj flexion torque, foot passive stiffness and foot-ankle reactive strength to explain 28% and 35% of the total variance in the effective vertical impulse and contact time. Ankle plantarflexor and quadriceps isometric torques were aggregately contributors of acceleration performance and separate contributors of cutting and jumping performance. In conclusion, MTPj flexion torque was more strongly associated with sprinting performance kinetics especially at high-speed. [ABSTRACT FROM AUTHOR]

Aims: The purpose of this study was to compare the effects of hamstring eccentric (NHE) strength training versus sprint training programmed as complements to regular soccer practice, on sprint performance and its mechanical underpinnings, as well as biceps femoris long head (BFlh) architecture. Methods: In this prospective interventional control study, sprint performance, sprint mechanics and BFlh architecture variables were compared before versus after six weeks of training during the first six preseason weeks, and between three different random match-pair groups of soccer players: "Soccer group" (n = 10), "Nordic group" (n = 12) and "Sprint group" (n = 10). Results: For sprint performance and mechanics, small to large pre-post improvements were reported in "Sprint group" (except maximal running velocity), whereas only trivial to small negative changes were reported in "Soccer group" and "Nordic group". For BFlh architecture variables, "Sprint" group showed moderate increase in fascicle length compared to smaller augment for the "Nordic" group with trivial changes for "Soccer group". Only "Nordic" group presented small increases at pennation angle. Conclusions: The results suggest that sprint training was superior to NHE in order to increase BFlh fascicle length although only the sprint training was able to both provide a preventive stimulus (increase fascicle length) and at the same time improve both sprint performance and mechanics. Further studies with advanced imaging techniques are needed to confirm the validity of the findings. [ABSTRACT FROM AUTHOR]

The article looks at challenges faced in the prevention of athletics injuries and illnesses. It references a number of surveillance studies on injury and illness incidences and characteristics in elite athletes. Other topics discussed include the difficulty to achieve consistent monitoring and medical follow-up and the challenge for athletics physicians to perform a consensual standardized method on injury and illness definitions.

Objective During international athletics championships, the incidence and characteristics of new injuries have been well described: about 10% of registered athletes have a new injury. It seemed also important to understand the complaints of athletes in terms of injuries in the period before and at the start of the championships and potential association with potential new injuries for identification of possible risk factors. The objective of this study was to determine the health of athletes before the start of an international athletics championship and to identify risk factors for new injuries. Patients and methods In the 2013 World Athletics Championships in Moscow, all athletes enrolled ( n = 1784) were asked to complete a pre-participation health questionnaire (PHQ) collecting data on the health status during the months preceding the championships. During the period of the Championships, all new injuries were prospectively recorded. Results The PHQ was completed by 698 (39%) of the athletes; 204 (29.2%) reported suffering such injury complaint during the month before the championships. The most common mode of onset of pain before championships was gradual (43.6%). Forty-nine athletes reported at least one new injury during the championships. Athletes who reported suffering injuries before championships had an increased risk of having a new injury during the championship [odds ratio (OR) = 2.09; 95% confidence interval (95% CI): 1.16–3.77; P = 0.014] and those who reported suffering injuries championships before a gradual fashion appearance were at increased risk of almost four times to re-injury with sport stop in the championship (OR = 3.92; 95% CI: 1.69–9.08; P = 0.001). Discussion/Conclusion Approximately one third of athletes participating in an international athletics championship and involved in this study reported an injury complaint during the month before the championships. This represented a risk factor to suffer a new injury during the championship. This study highlights the potential importance of a pre-participation health questionnaire as a screening tool to identify athletes at risk of injury before international athletics championships. [ABSTRACT FROM AUTHOR]

Opinion/Feedback Hamstring muscle injury is the main injury related to athletics, but also other sports including acceleration and sprints, with important consequences (time loss of sport and re-injury risk). In a prevention approach, a better knowledge of risk factors and mechanisms of these lesions seem relevant, and it can pass through a better understanding of the biomechanical and muscular determinants of performance in sprint and acceleration. The ability to produce a horizontal force on the ground [i.e. orienting the total push backward (or ground force reaction forward)], and to do so despite the increase in running speed, is an important determinant of sprint performance. The hamstring muscles seem to play an important role in this key ability. Evaluation of mechanical properties of sprint including the force-velocity profile and maximum theoretical horizontal force (FH0) and maximum theoretical speed (V0) in sprint is possible in real-practice conditions with simple tools. Studies have reported a change in the force-velocity profile and decrease in FH0 following hamstring muscle injury, which could be a consequence of the injury. This approach to analyse the hamstring propulsion function at a maximum acceleration sprint looks promising given the very functional and ecological character in a field evaluation, close links between the function and strength of hamstring and the horizontal force sprint, and these encouraging preliminary scientific results. This force-velocity profile evaluation could be used to guide the return to sprint and allow authorisation to maximum sprint after hamstring muscle injury, but also to screen athletes at risk of hamstring muscle injury. [ABSTRACT FROM AUTHOR]

Objective Vitamin D works on many biological parameters, functions and pathophysiological phenomena, such as bone metabolism but also extra-osseous metabolism (muscular role immunomodulator, cardiac, infectious). In France, the prevalence of vitamin D deficiency is estimated between 36% and 79–81% based on a threshold set at 50 nmol/L or 75 nmol/L, respectively. Due to these effects, vitamin D seems necessary to the health of athletes. The objective of this study was to determine the vitamin D status of in athletics athletes, and to analyse the possibilities of a screening questionnaire of vitamin D deficiency. Patients and methods We conducted a prospective study on an athletics season including high-level athletics athletes. Athletes performed 2 blood sample to determine the vitamin D level during the season: one in winter and one in summer, and completed a questionnaire on the day of the winter blood sample. Results During the winter, the average vitamin D level was 76.8 nmol/L and 72% of athletes had normal (greater than 50 nmol/L); 11.1% of athletes were impaired (below 30 nmol/L). During the summer, the average rate was 102.3 nmol/L, 95% of athletes had normal, and no athlete had a deficiency of vitamin D. There was a significant relationship between vitamin D levels and the score found by the questionnaire. The deficiency of factors that appeared to be significantly associated with vitamin D levels were: skin color, the use of sunscreen, working conditions for sun exposure and craving for the sun. Discussion/Conclusion The high-level athletics athletes were less deficient than the general population. This could be explained by the fact that they were training most often outside and had better eating habits. The questionnaire was correlated to blood sample for vitamin D and could be a relevant factor in the screening strategy. [ABSTRACT FROM AUTHOR]

Objective The epidemiology of injuries is the first step in the sports injuries prevention. In this context, the IAAF and EA have implemented a prospective injury follow-up during their international athletics championships since 2007, and the FFA initiated since the French championships in 2014. The aim of the study was to determine the incidence and characteristics of injuries during the French Elite championships. Patients and methods During the period of the outdoor and indoor French Elite championships, all newly occurring injuries were recorded by the local medical team. Results During the outdoor French Elite championships (2014 and 2015), an incidence of 40 to 60 injuries per 1000 registered athletes has been reported. The main diagnoses were: muscle injury hamstring and leg cramps. The injuries occurred mainly in combined events disciplines (20–50%), hurdles (37%), sprint (23–29%) and jumps (19%). It is also interesting to note that 50 athletes (9%) contested the championships and mentioned already present injury (occurred the previous day, weeks or months before the championships and/or recurrent during the championships). At the indoor French Elite championships (2014 and 2015), an incidence of 45–48 injuries per 1000 registered athletes has been reported. The main diagnosis was muscle hamstring injury, followed by knee injuries and ankle sprains. The injuries occurred primarily in jumps (29%), combined events (24%), sprint (17–24%) and hurdles (18%). Discussion/Conclusion It is emphasized that this is the first epidemiological data during the French Elite Athletics championships. This information is fundamental to understanding the risk of injury among Elite athletes at the French national level to develop well-adapted prevention measures to their own problems. The injury is multifactorial, its prevention requires the consideration and management of several parameters such as physical fitness, technical mastery of gesture, lifestyle, psychological aspects, a good course of treatment, equipment and sporting rules. [ABSTRACT FROM AUTHOR]

Objective The incidence of injuries in athletics is important, with consequences at short and long terms in sport, health, social and professional levels. It is therefore important to define strategies to reduce the incidence and severity of injuries in athletics. The objective of this study was to determine whether an injury prevention program (IPP) can reduce the occurrence and/or severity of injuries related to the practice of athletics. Material and methods The IPP has been developed, based on current scientific knowledge, targeting exercises on the most common injuries in athletics (hamstring muscle injury, Achilles and patellar tendinopathy, low back pain, ankle sprain) and selecting exercises known to treat and/or prevent these injuries (care stability, hamstrings and leg eccentric muscle strengthening, pelvis balance and stabilizing work). IPP takes about 15 minutes, 2 to 3 times per week, with progression levels. During the 2014–2015 athletic season, the IPP has been proposed in an athletic population, youth to senior at competition level and training at least 3 times a week, in who training loads, IPP compliance and injury complaints were collected. Results To date, 34 athletes were included and achieved 16 weeks of training including IPP. There was a significant correlation between the average number of IPP per week and number of weeks with an injury complaint ( r = −0.415; P = 0.02). The comparison between athletes who achieved the IPP least once a week and those having realized at least once a week found a significant difference in the number of weeks with an injury complaint (3.4 ± 1 3 vs. 1.3 ± 2.4, respectively, P = 0.04). The survival curve of the two groups showed a protective effect of IPP on the occurrence of an injury ( P = 0.05). Discussion/Conclusion These preliminary results were encouraging and reported that a suitable program, developed on a scientific basis and regularly performed, allowing a protective effect of the medium-term injury (of 4 months of training). [ABSTRACT FROM AUTHOR]

Objective The purpose of this study was to analyse the incidence and characteristics of muscle injuries and hamstring muscle injuries occurred during the international athletics championships from 2007 to 2015. Patients and methods National medical teams and local organizing committee physicians have collected every day all newly occurred injury whenever international championship from 2007 to 2015. Only the muscle injuries and hamstring muscle injuries, whatever gravity (cramp, contracture, rupture, avulsion), were analysed. Results A total of 720 muscle injuries have been reported on the total of 1762 recorded injuries, 40.9% of injuries; 57.5% ( n = 414) have resulted in time loss of sport. The overall incidence of muscle injuries was significantly higher among male athletes than female athletes (49.1 ± 4.4 vs. 28.7 ± 3.7 injuries per 1000 registered athletes, respectively; RR = 1.71; 95% CI: 1.46 to 2.00). A total of 185 hamstring muscle injuries were reported on the total of 1082 recorded injuries (9 championships included). This represented 17.1% of total injuries; 61.1% lead to time loss of sport. Hamstring muscle injuries represented 39.8% of all muscle damage, and 74.6% of all thigh muscle injuries. The overall incidence of hamstring muscle injuries was significantly higher in athletes than female athletes men (22.4 ± 3.4 vs. 11.5 ± 2.6 injuries per 1000 registered athletes, respectively; RR = 1 94; 95% CI: 1.42 to 2.66). The impacts of hamstring muscle injuries were significantly higher in male than female athletes for the sprints, hurdles and jumps. There was no difference between male and female athletes in the frequency of hamstring muscle injuries between outdoor and indoor championships, the type, cause, severity, discipline and age categories. Discussion/Conclusion During international athletics championships, muscle injury is the principal type of injury, and among those, the hamstring is the most commonly affected, with a two times higher risk in male than female athletes. Athletes in explosive power events, male athletes and older male athletes, in specific were more at risk of muscle injuries and hamstring injuries. Injury prevention strategies should be sex-specific. [ABSTRACT FROM AUTHOR]

Objective The hamstring muscles are the most injured muscles in athletes practicing sprints. However, they seem greatly contributing to the production of horizontal force, a key element in the sprint acceleration performance. The aim of our study was to experimentally analyse the link between the production of horizontal force and strength of the hamstrings at maximum sprints on a treadmill and in fatigue conditions. Patients and methods Fourteen male subjects accustomed to sprint participated in the experiment consisting in 12 6-seconds sprints separated by 44 seconds of recovery on an instrumented treadmill sprint for measuring the horizontal force, coupled with the simultaneous recording of the EMG activity of the vastus lateralis, rectus biceps femoris and gluteus muscles. Before and after the 12 sprints, the maximum isokinetic strength of the flexors and extensors of the hip and knee was measured on isokinetic dynamometer type CONTREX with 3 maximum repetitions at 120°/s in concentric and eccentric. A comparison before and after analysis and correlation between the parameters was carried out. Results At the maximum sprint, the multiple linear regression analysis showed a significant relationship ( P = 0.02) between the horizontal force and the combination of EMG activity of the biceps femoris in late swing phase of the stride and the eccentric isokinetic strength of the knee flexors. After the 12 sprints, there was a significant decrease ( P < 0.05) in the sprint performance, horizontal force, isokinetic strength and muscle activity. And there was a significant correlation between the horizontal force and eccentric strength of the knee extensors, and concentric strength of hip extensors. Discussion/Conclusion For a high-performance acceleration, it would seem necessary to be able both to strongly activate the hamstrings just before ground contact and have a great capacity eccentric strength of the hamstrings. In fatigue conditions, horizontal force reduction would seem not only related to the strength of decreased hamstring, but with d knee extensors eccentric strength decrease. [ABSTRACT FROM AUTHOR]

Keywords: Hamstring muscles; rupture test; injury; energy; peeling EN Hamstring muscles rupture test injury energy peeling S223 S225 3 11/26/20 20200902 NES 200902 1. For peeling tests, the energy release rate Graph HT ht (characterising crack opening of the tissue in cross-fibre direction in the Graph HT ht cycle) was calculated with Graph HT ht the fracture energy released and Graph HT ht the exposed area during the Graph HT ht cycle. Conclusion Our study on hamstring muscles from rabbits suggests that the Biceps Femoris could be the weakest point of the hamstring group, with its musculotendinous junctions being possible damage initiation sites. [Extracted from the article]

Purpose: Evaluate the current state of sports injury prevention perception, knowledge and practice among sports medicine professionals located in Western Europe and involved in injury prevention. Methods: Members of two different sports medicine organizations (GOTS and ReFORM) were invited to complete a web-based questionnaire (in German and in French, respectively) addressing perception, knowledge and implementation of sports injury prevention through 22 questions. Results: 766 participants from a dozen of countries completed the survey. Among them, 43% were surgeons, 23% sport physicians and 18% physiotherapists working mainly in France (38%), Germany (23%) and Belgium (10%). The sample rated the importance of injury prevention as "high" or "very high" in a majority of cases (91%), but only 54% reported to be aware of specific injury prevention programmes. The French-speaking world was characterized by lower levels of reported knowledge, unfamiliarity with existing prevention programmes and less weekly time spent on prevention as compared to their German-speaking counterparts. Injury prevention barriers reported by the respondents included mainly insufficient expertise, absence of staff support from sports organizations and lack of time. Conclusion: There is a lack of awareness regarding injury prevention concepts among sports medicine professionals of the European French- and German-speaking world. This gap varied according to the professional occupation and working country. Relevant future paths for improvement include specific efforts to build awareness around sports injury prevention. Level of evidence: Level IV. [ABSTRACT FROM AUTHOR]

Introduction: Given the prevalence of hamstring injuries in football, a rehabilitation program that effectively promotes muscle tissue repair and functional recovery is paramount to minimize reinjury risk and optimize player performance and availability. Purpose: This study aimed to assess the concurrent effectiveness of administering an individualized and multifactorial criteria-based algorithm (rehabilitation algorithm [RA]) on hamstring injury rehabilitation in comparison with using a general rehabilitation protocol (RP). Methods: Implementing a double-blind randomized controlled trial approach, two equal groups of 24 football players (48 total) completed either an RA group or a validated RP group 5 d after an acute hamstring injury. Results: Within 6 months after return to sport, six hamstring reinjuries occurred in RP versus one injury in RA (relative risk = 6, 90% confidence interval = 1-35; clinical inference: very likely beneficial effect). The average duration of return to sport was possibly quicker (effect size = 0.34 ± 0.42) in RP (23.2 ± 11.7 d) comparedwith RA (25.5 ± 7.8 d) (-13.8%, 90% confidence interval = -34.0% to 3.4%; clinical inference: possibly small effect). At the time to return to sport, RA players showed substantially better 10-m time, maximal sprinting speed, and greater mechanical variables related to speed (i.e., maximum theoretical speed and maximal horizontal power) than the RP. Conclusions: Although return to sport was slower, male football players who underwent an individualized, multifactorial, criteria-based algorithm with a performance- and primary risk factor-oriented training program from the early stages of the process markedly decreased the risk of reinjury compared with a general protocol where long-length strength training exercises were prioritized. [ABSTRACT FROM AUTHOR]

Objective: For the 3 Nordic ski disciplines of cross-country skiing, Nordic combined, and ski jumping, data on injuries and illnesses during major sporting events only exist from the Winter Olympics of 2010 to 2018. So far, an investigation has not been conducted during the Nordic World Ski Championships. Design: Prospective cohort study. Setting: Fédération Internationale de Ski (FIS) Nordic World Ski Championships 2021 in Oberstdorf, Germany. Participants: Overall, 663 athletes from 65 nations participated in the FIS Nordic World Ski Championships 2021. The study population included 344 athletes from 32 nations. Interventions: National medical teams were invited to report daily all newly incurred or exacerbated injuries and illnesses. Main Outcome Measures: All reported injuries and illnesses that occurred during the championships from February 23 until March 7, 2021, were analyzed. Injury and illness rates were calculated with 95% confidence intervals (95% CIs). Results: The 32 reporting nations returned 88.4% of the daily report forms. The incidence of injuries was 4.7 (95% CI, 2.4-6.9) per 100 athletes in the 3 Nordic ski disciplines. The incidence of illness was also 4.7 (95% CI, 2.4-6.9) per 100 athletes with a relative proportion of infection-related illnesses of 31.3%. Conclusions: Although the incidence of injuries of the Nordic disciplines was comparable with those of the 2010 to 2018 Winter Olympics, the incidence of illnesses was lower than during the previous 3 Winter Olympic Games with a lower rate of infection-related illnesses. This might be caused by the high hygiene measures due to the coronavirus disease 2019 pandemic. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to investigate lactate recovery kinetics after high-intensity exercises.Methods: Six competitive middle-distance runners performed 500-, 1000-, and 1500-m trials at 90 % of their current maximal speed over 1500 m. Each event was followed by a passive recovery to obtain blood lactate recovery curves (BLRC). BLRC were fitted by the bi-exponential time function: La(t) = La(0) + A 1(1-e (-γ1t) ) + A 2(1-e (-γ2t) ), where La(0) is the blood lactate concentration at exercise completion, and γ 1 and γ 2 enlighten the lactate exchange ability between the previously active muscles and the blood and the overall lactate removal ability, respectively. Applications of the model provided parameters related to lactate release, removal and accumulation rates at exercise completion, and net amount of lactate released during recovery.Results: The increase of running distance was accompanied by (1) a continuous decrease in γ 1 (p < 0.05), (2) a primary decrease (p < 0.05) and then a stabilization of γ 2, and (3) a constant increase in blood concentrations (p < 0.05) and whole body accumulation of lactate (p < 0.05). Estimated net lactate release, removal and accumulation rates at exercise completion, as well as the net amount of lactate released during recovery were not significantly altered by distance.Conclusion: Alterations of lactate exchange and removal abilities have presumably been compensated by an increase in muscle-to-blood lactate gradient and blood lactate concentrations, respectively, so that estimated lactate release, removal and accumulation rates remained almost stable as distance increased. [ABSTRACT FROM AUTHOR]

Background The International Association of Athletics Federation has systematically surveyed all Athletics injuries in their competitions since 2007 in order to develop strategies for health protection of their athletes. Aims Analysis of frequency and characteristics of injuries during 13 international Athletics championships from 2007 to 2012 regarding different types of championships and discipline categories. Methods The team physicians and the Local Organizing Committee reported daily all injuries on a standardised injury report form during each championship. Results A total of 1470 injuries were reported, equivalent to 81.1±4.2 injuries per 1000 registrations of which 36.7±2.9 were expected to result in absence from sports. The incidence of time-loss injuries was significantly higher in competition (29.0±2.6) than in training (5.8±1.9), and in outdoor (46.4±4.0) than in indoor (23.7±6.2) or youth/junior championships (13.2±4.0). While most in-competition time-loss injuries were reported during short distance events (32.5%), combined events had the highest incidence of incompetition time-loss injuries (106±26.5). The most frequent diagnosis was thigh strain (28.2%), followed by lower leg strain and ankle sprain. Injury location varied between different discipline categories: in long distances the lower leg, in Marathon the foot and in throws the upper extremity were mainly affected. Conclusions The incidence of injuries varied substantially between different types of Athletics championships and between discipline categories. Special attention should be paid to combined events, running disciplines and (thigh) strain to better understand the injury mechanisms and risk factors and develop related preventive measures. [ABSTRACT FROM AUTHOR]

Sprint mechanics and field 100-m performances were tested in 13 subjects including 9 non-specialists, 3 French national-level sprinters and a world-class sprinter, to further study the mechanical factors associated with sprint performance. 6-s sprints performed on an instrumented treadmill allowed continuous recording of step kinematics, ground reaction forces (GRF), and belt velocity and computation of mechanical power output and linear force-velocity relationships. An index of the force application technique was computed as the slope of the linear relationship between the decrease in the ratio of horizontal-to-resultant GRF and the increase in velocity. Mechanical power output was positively correlated to mean 100-m speed ( P < 0.01), as was the theoretical maximal velocity production capability ( P < 0.011), whereas the theoretical maximal force production capability was not. The ability to apply the resultant force backward during acceleration was positively correlated to 100-m performance ( r > 0.683; P < 0.018), but the magnitude of resultant force was not ( P = 0.16). Step frequency, contact and swing time were significantly correlated to acceleration and 100-m performance (positively for the former, negatively for the two latter, all P < 0.05), whereas aerial time and step length were not (all P > 0.21). Last, anthropometric data of body mass index and lower-limb-to-height ratio showed no significant correlation with 100-m performance. We concluded that the main mechanical determinants of 100-m performance were (1) a 'velocity-oriented' force-velocity profile, likely explained by (2) a higher ability to apply the resultant GRF vector with a forward orientation over the acceleration, and (3) a higher step frequency resulting from a shorter contact time. [ABSTRACT FROM AUTHOR]

Abstract: We investigated the changes in the technical ability of force application/orientation against the ground vs. the physical capability of total force production after a multiple-set repeated sprints series. Twelve male physical education students familiar with sprint running performed four sets of five 6-s sprints (24s of passive rest between sprints, 3min between sets). Sprints were performed from a standing start on an instrumented treadmill, allowing the computation of vertical (F V), net horizontal (F H) and total (F Tot) ground reaction forces for each step. Furthermore, the ratio of forces was calculated as RF=F H F Tot −1, and the index of force application technique (D RF) representing the decrement in RF with increase in speed was computed as the slope of the linear RF-speed relationship. Changes between pre- (first two sprints) and post-fatigue (last two sprints) were tested using paired t-tests. Performance decreased significantly (e.g. top speed decreased by 15.7±5.4%; P<0.001), and all the mechanical variables tested significantly changed. F H showed the largest decrease, compared to F V and F Tot. D RF significantly decreased (P<0.001, effect size=1.20), and the individual magnitudes of change of D RF were significantly more important than those of F Tot (19.2±20.9 vs. 5.81±5.76%, respectively; P<0.01). During a multiple-set repeated sprint series, both the total force production capability and the technical ability to apply force effectively against the ground are altered, the latter to a larger extent than the former. [Copyright &y& Elsevier]

International outdoor athletics championships are typically hosted during the summer season, frequently in hot and humid climatic conditions. Therefore, we analyzed the association between apparent temperature and heat-related illnesses occurrence during international outdoor athletics championships and compared its incidence rates between athletics disciplines. Heat-related illnesses were selected from illness data prospectively collected at seven international outdoor athletics championships between 2009 and 2018 using a standardized methodology. The Universal Thermal Climate Index (UTCI) was calculated as a measure of the apparent temperature based on weather data for each day of the championships. Heat-related illness numbers and (daily) incidence rates were calculated and analyzed in relation to the daily maximum UTCI temperature and between disciplines. During 50 championships days with UTCI temperatures between 15°C and 37°, 132 heat-related illnesses were recorded. Average incidence rate of heat-related illnesses was 11.7 (95%CI 9.7 to 13.7) per 1000 registered athletes. The expected daily incidence rate of heat-related illnesses increased significantly with UTCI temperature (0.12 more illnesses per 1000 registered athletes/°C; 95%CI 0.08-0.16) and was found to double from 25 to 35°C UTCI. Race walkers (RR = 45.5, 95%CI 21.6-96.0) and marathon runners (RR = 47.7, 95%CI 23.0-98.8) had higher heat-related illness rates than athletes competing in short-duration disciplines. Higher UTCI temperatures were associated with more heat-related illnesses, with marathon and race walking athletes having higher risk than athletes competing in short-duration disciplines. Heat-related illness prevention strategies should predominantly focus on marathon and race walking events of outdoor athletics championships when high temperatures are forecast. [ABSTRACT FROM AUTHOR]

An association has been reported between dynamic anterior pelvic tilt (APT) and hamstring injuries; however, no research has examined if a training-based preventive intervention could alter APT. Therefore, the aim of the present study was to examine if a specific 6-week multimodal intervention, based on the theoretical influence of neighbouring joints and biomechanical interactions between muscles that are inserted to the pelvis, induced changes in APT, during walking gait, hamstring flexibility and trunk endurance. Thirty-five active healthy males volunteered for this single-blind controlled trial and were split into two groups based on baseline data: a control group (CG, n = 20, continued their normal physical activities), and an intervention group (IG, n = 15, performed the intervention programme for 18 sessions over 6 weeks). A significant (p = 0.001) decrease in the APT kinematics during gait, significant increase in the Active Knee Extension Test (p = 0.001), and a significant increase in trunk endurance performance for flexion (p = 0.001), extension (p = 0.001) and side bridge (p = 0.001) were observed, in IG after the 6-week programme, compared to CG. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate improvements in functional performance through the use of the Limb Symmetry Index of Single and Triple Hop tests between 12 and 52 weeks after anterior cruciate ligament reconstruction, and to compare these values with usual time-based and performance-based criteria used during the return to sport continuum. Repeated functional assessments using Single and Triple Hop Tests at 12, 16, 22, 26, 39 and 52 postoperative weeks were evaluated. At each session, the median and interquartile range of Limb Symmetry Index of tests were calculated and compared with the usual criteria: return to participation:≥85%, between 12–16 w; return to play:≥90%, between 26–39 w. The results indicate that the median increased over time to 39 postoperative weeks and then stabilized. For Single Hop Test, wide variability was seen at 12 and 16 weeks (interquartile range=20%); this was lower from 22 to 52 weeks (interquartile range=8–6%). At 12 weeks for Single Hop Test, the median was 83.6% and did not meet>85% criteria for return to participation. Hop tests could be interesting functional tests to follow the functional recovery and help decision-making regarding return to participation and return to play. [ABSTRACT FROM AUTHOR]

This study aimed to assess prevalence and incidence of chronic exertional compartmental syndrome as well as functional outcomes after surgery in elite Nordic skiers. An exhaustive list of 294 elite Nordic skiers from the French national teams between 1994 and 2014 was analyzed through their individual medical files in order to identify cases of chronic exertional compartmental syndrome. Eighteen athletes had confirmed diagnosis and performed a structured interview to identify factors associated with chronic exertional compartmental syndrome and surgery outcomes. The prevalence was 6.1% and the incidence 13 per 1000 skier-years. Biathletes had a higher prevalence than cross-country skiers (OR=0.40, p=0.08). Free-technique skiing and roller-skiing were the main conditions inducing symptoms. All injured athletes had bilateral surgery and 94% of them reported no more or sporadic leg pain after. Almost 90% resumed competition at the same or higher level than prior surgery. Compare to previous studies, the incidence rate of chronic exertional compartmental syndrome is higher in French elite Nordic skiers. The higher prevalence in biathletes and the trigger during free-technique skiing suggest a contribution of this technique to this disease. This study also confirmed that surgery was an efficient therapeutic solution without compromising athletes' career. [ABSTRACT FROM AUTHOR]

Highlights • To test shoulder instability, it is preferred to have the subject in the apprehension position (abduction and external rotation). • The results of that kind of test could lead to an evaluation protocol to test shoulder instability and document the patient's improvements during the rehabilitation program. • Shoulder steadiness characterized by the center of pressure excursion displacement and free moment variation of seated subjects was tested. • The test–retest reliability of this new shoulder stability test in seated able-bodied subjects using different arm loading conditions was high with sufficient loading (3 kg) and 3 trials. Abstract Shoulder performance and sensorimotor control assessments help to identify shoulder instabilities and document the rehabilitation progress. Testing seated subjects in a position of hand prehension requires less controlled adjustments to maintain body balance in a clinically relevant situation. The objective of this work was to determine the test–retest repeatability of a novel shoulder stability test in seated subjects with the ipsi-lateral hand in prehension during four arm loading conditions. Able-bodied subjects were seated on a rigid chair fixed to a force plate. A horizontally and posteriorly directed force was applied to the hand for four 4 loading conditions ranging from 0 to 3 kg. Ten postural balance parameters were calculated from the center of pressure displacements and its corresponding free moments. Intra-class correlation coefficients were calculated for three consecutive trials and for four loading conditions. Generally, the intra-class correlations values increased gradually with the load and varied from 0.727 to 0.948. Tz values increased non-linearly with the applied load. The test–retest reliability of a new shoulder stability test in seated able-bodied subjects was high with sufficient loading (3 kg) and 3 trials. [ABSTRACT FROM AUTHOR]

Introduction: Shoulder pain is highly prevalent in competitive swimmers, and generalized joint hypermobility (GJH) is considered a risk factor. Sensorimotor control deficiencies and altered neuromuscular activation of the shoulder may represent underlying factors.Research Question: To investigate whether competitive swimmers with GJH including shoulder hypermobility (GJHS) differ in shoulder sensorimotor control and muscle activity from those without GJH and no shoulder hypermobility (NGJH).Methods: Competitive swimmers (aged 13-17) were recruited. GJHS or NGJH status was determined using the Beighton score (0-9) and Rotès-Quérol test (positive/negative). Inclusion criteria for GJHS were a Beighton score ≥5 and minimum one hypermobile shoulder, while NGJH was defined as a Beighton score ≤3 and no shoulder hypermobility. Three prone lying, upper-extremity weight-bearing shoulder stabilometric tests were performed on a force platform: Bilateral upper-extremity support eyes open (BL-EO) and eyes closed (BL-EC) and unilateral upper-extremity support eyes open (UL-EO). Surface electromyography (SEMG) was measured from the upper trapezius, lower trapezius, serratus anterior, infraspinatus and pectoralis major muscles. SEMG was normalized using maximal voluntary isometric contractions and presented relative to maximal voluntary SEMG (%MVE). Co-contraction index (CCI) was calculated for the following muscle pairs: upper trapezius-lower trapezius, upper trapezius-serratus anterior, and infraspinatus-pectoralis major. Between-group differences in stabilometric parameters, %MVE, and CCI were analyzed with a mixed effects model.Results: Thirty-eight swimmers were enrolled as GJHS (n = 19) or NGJH (n = 19). There were no group differences in stabilometric parameters or CCI. GJHS displayed significantly decreased (29%) pectoralis major activity during BL-EO compared to NGJH (5.35 ± 1.77%MVE vs. 7.51 ± 1.96%MVE; p = 0.043).Significance: Adolescent competitive swimmers with GJHS displayed no shoulder sensorimotor control deficiencies and no generally altered shoulder muscle activity pattern, except for decreased pectoralis major activity in BL-EO. Longitudinal studies are needed to investigate whether decreased pectoralis major activation contributes to the development of shoulder pain in swimmers with GJHS. [ABSTRACT FROM AUTHOR]

This study set out to identify factors critical for the usability of electronic data collection in association with championships in individual sports. A qualitative analysis of electronic data collection system usability for collection of data on pre-participation health from athletes and in-competition injury and illness from team physicians was performed during the 2013 European Athletics Indoor Championships. A total of 15 athletes and team physicians participated. Athletes were found to experience few problems interacting with the electronic data collection system, but reported concerns about having to reflect on injury and illness before competitions and the medical terminology used. Team physicians encountered problems when first navigating through the module for clinical reporting, but they were not subjected to motivational problems. We conclude that athletes’ motivation to self-report health data and the design of the human–computer interface for team physicians are key issues for the usability of electronic data collection systems in association with championships in individual sports. [ABSTRACT FROM AUTHOR]

Objective After anterior cruciate ligament (ACL) tear, the ACL reconstruction (ACLR) is the standard treatment to return to pivots/contacts sports. The goal of rehabilitation programs is to guide the functional recovery and the safe return to sport without additional knee injury or other injuries. Functional tests, like Hop tests and their side to-side difference index [limb symmetry index (LSI)], are commonly used following ACLR to help return to sport decision making. However, the most commonly used criterion to return to sport is the postoperative time: return to light activities (RtlA) at 3 or 4 month mark and return to sport with contacts and side-cuttings (RtS) between 6 and 9 month mark. The aim of this study was to analyse the functional recovery after ACLR using the standard hops LSI scores and compare these scores with usual timeline of RtlA and RtS. Patients and methods Thirty-one patients with ACLR (19 males) with a mean age of 23 ± 7 years. Functional recovery was evaluated during rehabilitation and return to sports phases (from 3 to 12 months postoperatively), with 2 straight one-legged Hop tests for distance (Single and Triple Hop tests). The LSI was calculated for each test. A non-linear regression was calculated to obtain predictive values of 3, 4, 6 and 9 months postoperatively. Results At 3 months, Hop tests LSI was nearly 80%, with great variability [interquartile range (IQR): 75%–95%]. At 4 months, Hop tests LSI was just under 85% but with important variability (IQR: 78%–94%). At 6 months, Hop tests LSI was about 90%, and over 90% at 9 months. From 6 postoperatively, the variability decreased (IQR: 94%–99%). Discussion/Conclusion Comparing our results with the usual timeline of RtlA, we can say that the timeline of 3 months postoperatively is a little too short to RtlA. At 4 months postoperatively, the functional recovery can allow a safely RtlA. At 6 months postoperatively, the LSI is greater than 90%, allowing RtS. Given the great variability between patients before 6 months postoperatively, this functional assessment could be used in association with clinical and isokinetic evaluations to individualize the decision to return to sport. [ABSTRACT FROM AUTHOR]

Objective The objective of this study was to determine the incidence, characteristics and risk factors of injuries to French golfers high-level. Material and methods It was a national retrospective study by mailing a questionnaire to all the French Golf licensed under ten handicap. The questionnaire collected information on the characteristics of the player, practicing golf, equipment and the occurrence or not of an injury during the season 2015. A descriptive analysis and a comparison between the injured and uninjured golfers were made, followed by univariate and multivariate analysis to investigate potential risk factors. Results A total of 1382 golfers returned a full questionnaire and were therefore included in the study. We found 712 injuries (52%) and an incidence of 1.99 injuries per 1000 hours of playing golf. The most frequent injuries were at: lumbar spine (21.2%), the dominant shoulder (7.8%) and the thoracic spine (7.4%). An analysis was also performed by gender who did not find differences in the occurrence of an injury between women and men. The injury number 1 in men was located at the lumbar spine (23.1%) and among women in the dominant shoulder (11%) and lumbar spine (11%). We noted a recurrence in 37% of injuries in women and 44.8% in men. The injury dragged her into 53% of cases in men and 56.1% in women judgment of golf and in 9.4% of men and 8.7% of women work stoppage. Protective factors highlighted were the absence of upper limb overuse or wearing heavy workload, lack of monitoring by a golf professional ( P = 0.026). Contributing factors were a number of months per year high set ( P = 0.0127) and recent use of clubs ( P = 0.0034). Discussion/Conclusion Golf is a provider of injuries with a high-level of golfer two injuries in a season. Prevention must be the heart of the management of golfer taking into account the protective factors and risk factors. [ABSTRACT FROM AUTHOR]

Purpose: The Hemi-Castaing ligamentoplasty uses a powerful dynamic stabilizer of the ankle which is the peroneus brevis tendon. To our knowledge, there is no study available evaluating the effects of this type of surgery on proprioceptive, muscular and posturographic parameters.Methods: This case-control study included 39 subjects divided into two groups: the operated (n = 24) and the control group (n = 15). All subjects underwent a clinical, proprioceptive and isokinetic assessment using a CON-TREX dynamometer, and a postural evaluation using the Win-Posturo force platform.Results: At a mean period of 23 (SD 5.4) post-operative months, the Karlsson ankle functional score was 84.2 (SD 23.8) and the AOFAS score was 88.1 (SD 16.2). The mean ankle joint position error for operated ankles was from 1.9° (SD 0.9) at 10° of inversion range of motion to 2.5° (SD 1.7) at 20°. It was similar to that achieved in the control group ranging from 2.2° (SD 1) at 10° to 2.3° (SD 1.3) at 20°. No significant loss of ankle eversion strength could be observed after ligamentoplasty. Ankle eversion/inversion ratio when tested under all velocities and contraction modes failed to reveal any statistical difference between the operated and healthy ankles in the patient group, neither between the patient and control groups.Conclusions: This surgical technique achieved excellent functional outcomes. It did not impair the agonist/antagonist balance of ankle muscles, and use of half the peroneus brevis tendon did not lessen the eversion strength.Level Of Evidence: Case-control study, Level III. [ABSTRACT FROM AUTHOR]