Hip and core exercise programme prevents running-related overuse injuries in adult novice recreational runners: a three-arm randomised controlled trial (Run RCT).

OBJECTIVE: This study aims to investigate the efficacy of two exercise interventions in reducing lower extremity (LE) injuries in novice recreational runners. METHODS: Novice runners (245 female, 80 male) were randomised into hip and core (n=108), ankle and foot (n=111) or control (n=106) groups. Interventions were completed before running and included exercise programmes focusing on either (1) hip and core or (2) ankle and foot muscles. The control group performed static stretching exercises. All groups were supervised by a physiotherapist and performed the same running programme. Injuries and running exposure were registered using weekly questionnaires during the 24-week study. Primary outcome was running-related LE injury. RESULTS: The incidence of LE injuries was lower in the hip and core group compared with the control group (HR 0.66; 95% CI 0.45 to 0.97). The average weekly prevalence of overuse injuries was 39% lower (prevalence rate ratio, PRR 0.61, 95% CI 0.39 to 0.96), and the prevalence of substantial overuse injuries was 52% lower (PRR 0.48, 95% CI 0.27 to 0.90) in the hip and core group compared with the control group. No significant difference was observed between the ankle and foot group and control group in the prevalence of overuse injuries. A higher incidence of acute injuries was observed in the ankle and foot group compared with the control group (HR 3.60, 95% CI 1.20 to 10.86). CONCLUSION: A physiotherapist-guided hip and core-focused exercise programme was effective in preventing LE injuries in novice recreational runners. The ankle and foot programme did not reduce LE injuries and did not protect against acute LE injuries when compared with static stretching.

Perspectives of Ballet Dancers on Causes of Their Injuries and Implementation of Injury Preventive Measures by Ballet Teachers and Masters.

OBJECTIVES: Ballet dancers have a high injury risk. We aimed to gain insight into the causes for acute and overuse injuries in ballet dancers and the level of implementation of injury prevention by ballet teachers/masters, as perceived by dancers. METHODS: An international cross-sectional online-survey was based on the Fit-to-Dance Questionnaire and literature. Adult amateur, pre-professional, and professional ballet dancers reported the perceived causes of their injuries sustained in the previous 2 years. Multiple answers per injury were possible. Also, dancers rated the level of implementation of measures to prevent injury by their ballet teachers and ballet masters based on 21 items using a 5-point Likert scale. Causes were analyzed per-injury as well as per-dancer. RESULTS: 188 ballet ensembles and 51 dance organizations were contacted, from which 192 ballet dancers (mean age 27 ±7.8 yrs, 83% females) responded. 119 dancers (62%) reported 203 acute and 164 (85%) reported 469 overuse injuries. Fatigue was the most frequently perceived cause for acute injuries in the per-injury (n=89, 43.8%) and per-dancer analysis (n=63, 32.8%). For overuse injuries, pressure from the teacher/master was most frequently perceived as cause in the per-injury analysis (n=240, 51.2%), specifically in pre-/professional dancers (n=233, 61.3%). In the per-dancer analysis, fatigue/overtraining scored highest for overuse injuries (n=107; 55.7%). Other causes were previous/repetitive injuries (acute-per-injury 26.1%, acute-per-dancer 22.4%; overuse-per-injury 46.3%, overuse-per-dancer 53.1%) or erroneous dance technique (acute-per-injury 24.6%, acute-per-dancer 21.9%; overuse-per-injury 47.8%, overuse-per-dancer 45.3%). With regard to perceived level of implementation of injury preventive measures by ballet teachers/masters to prevent musculoskeletal injuries, 2 items received high ratings, 12 moderate ratings and 6 low ratings. CONCLUSIONS: Fatigue and pressure accounted for the majority of perceived causes for injuries. Perceived support by ballet teachers/masters regarding injury prevention was moderate to low. Future research should focus on the awareness, attitudes, and the important role of ballet teachers/masters for injury prevention in dancers.

Surfing on the world stage: a narrative review of acute and overuse injuries and preventative measures for the competitive and recreational surfer.

Surfing has rapidly grown in popularity as the sport made its debut at the Tokyo 2020 Olympic Games. Surfing injuries are becoming more relevant with the globalisation and increasing risks of the sport, but despite this, little is known about surfing injuries or prevention strategies in either the competitive or recreational surfer. Prior research demonstrates that surfers are injured at a frequency of 0.74-1.79 injuries per 1000 hours of surfing. We reviewed the literature for the incidence, anatomical distribution, type and underlying mechanism of acute and overuse injuries, and discuss current preventative measures. This review finds that skin injuries represent the highest proportion of total injuries. Acute injuries most frequently affect the head, neck and face, followed by the lower limbs. Being struck by one's own board is the most common mechanism of injury. Non-contact acute ligament injuries have increased as surfing manoeuvres have become more acrobatic and overuse musculoskeletal injuries are highly correlated with paddling. However, there is a paucity of research for surfing injuries, and studies on overuse musculoskeletal injuries and prevention are disproportionally under-represented. Most of the prior studies are limited by small sample sizes, poor data collection methodology and geographical constraints. Further research is needed to establish preventative measures for both acute and overuse surfing injuries and to ensure the increasing popularity of surfing is met with an improved understanding of sport risks and safety. Specifically, we recommend research be prioritised regarding the efficacy of training programmes to prevent surfing-related overuse musculoskeletal injuries.

Manual Therapy Facilitates Homeostatic Adaptation to Bone Microstructural Declines Induced by a Rat Model of Repetitive Forceful Task.

The effectiveness of manual therapy in reducing the catabolic effects of performing repetitive intensive force tasks on bones has not been reported. We examined if manual therapy could reduce radial bone microstructural declines in adult female Sprague-Dawley rats performing a 12-week high-repetition and high-force task, with or without simultaneous manual therapy to forelimbs. Additional rats were provided 6 weeks of rest after task cessation, with or without manual therapy. The control rats were untreated or received manual therapy for 12 weeks. The untreated TASK rats showed increased catabolic indices in the radius (decreased trabecular bone volume and numbers, increased osteoclasts in these trabeculae, and mid-diaphyseal cortical bone thinning) and increased serum CTX-1, TNF-α, and muscle macrophages. In contrast, the TASK rats receiving manual therapy showed increased radial bone anabolism (increased trabecular bone volume and osteoblast numbers, decreased osteoclast numbers, and increased mid-diaphyseal total area and periosteal perimeter) and increased serum TNF-α and muscle macrophages. Rest, with or without manual therapy, improved the trabecular thickness and mid-diaphyseal cortical bone attributes but not the mineral density. Thus, preventive manual therapy reduced the net radial bone catabolism by increasing osteogenesis, while rest, with or without manual therapy, was less effective.

Women's wrist and elbow at work: analysis of acute injuries and cumulative trauma disorders to improve ergonomics in female-dominated activities.

The aim of this study is to analyse women's wrist and elbow acute work injuries together with cumulative trauma disorders, such as carpal tunnel syndrome (CTS) and epicondylitis. Five years records (2015-2019) on women's wrist/elbow acute work injuries and CTS/epicondilytis, from Italian National Compensation Authority, were collected and pooled all together as 'dis-ac' (disorders + acute) events. A statistical analysis was performed in comparing the different female-dominated work sectors. Results showed that hairdressing/laundry sector was associated with the highest risk for wrist acute work injuries and cleaning for elbow while manufacturing for CTS and epicondylitis. Hairdressing/laundry and manufacturing were associated with the highest risk for dis-ac events (hairdressing: wrist dis-ac OR: 4.89; CI 95% 4.22-5.67; elbow dis-ac OR: 3.70; CI 95% 2.99-4.58; manufacturing: wrist dis-ac OR: 3.39; CI 95% 3.13-3.66; elbow dis-ac OR: 2.45; CI 95% 2.20-2.73). The relationship between acute injuries and cumulative trauma disorders is discussed to preserve women's safety and health in ergonomics.Practitioner Summary: Women's wrist and elbow acute work injuries and cumulative trauma disorders (carpal tunnel syndrome and epicondylitis) were analysed and studied all together (dis-ac events) in female-dominated activities. Hairdressing and manufacturing work sectors were associated with the highest risk, showing the need to safeguard the health and safety of female workers.

Injuries and illnesses among competitive Norwegian rhythmic gymnasts during preseason: a prospective cohort study of prevalence, incidence and risk factors.

OBJECTIVES: Rhythmic gymnastics is an Olympic sport that demands high training volume from early age. We investigated the extent of, and risk factors for, injuries among competitive Norwegian rhythmic gymnasts. METHODS: One hundred and seven of 133 (80.5%) female rhythmic gymnasts (mean age: 14.5 years (SD 1.6), mean body mass index: 18.9 (SD 2.2)) participated. All gymnasts completed a baseline questionnaire and the 'Triad-Specific Self-Report Questionnaire'. Injuries, illnesses and training hours were recorded prospectively for 15 weeks during preseason using the 'Oslo Sports Trauma Research Center Questionnaire on Health Problems' (OSTRC-H2). RESULTS: Response rate to OSTRC-H2 was 97%. Mean overuse and acute injury prevalence were 37% (95% CI: 36% to 39%) and 5% (95% CI: 4% to 6%), respectively. Incidence was 4.2 overuse injuries (95% CI: 3.6 to 4.9) and 1.0 acute injuries (95% CI: 0.5 to 1.6) per gymnast per year. Overuse injuries in knees, lower back and hip/groin represented the greatest burdens. Previous injury increased the odds of injury (OR 30.38, (95% CI: 5.04 to 183.25)), while increased age (OR 0.61 per year, (95% CI: 0.39 to 0.97)) and presence of menarche (OR: 0.20, (95% CI: 0.06 to 0.71)) reduced the odds of all injuries and substantial injuries, respectively. CONCLUSIONS: Overuse injuries were common among Norwegian rhythmic gymnasts. Younger gymnasts had higher all-injury risk. Gymnasts who were not menstruating had higher substantial injury risk. Injury prevention interventions should start at an early age and focus on preventing knee, lower back and hip/groin injuries.

Defining a Research Agenda for Youth Sport Specialization in the United States: The AMSSM Youth Early Sport Specialization Summit.

ABSTRACT: Sport specialization is becoming increasingly common among youth and adolescent athletes in the United States and many have raised concern about this trend. Although research on sport specialization has grown significantly, numerous pressing questions remain pertaining to short- and long-term effects of specialization on the health and well-being of youth, including the increased risk of overuse injury and burnout. Many current elite athletes did not specialize at an early age. Methodological and study design limitations impact the quality of current literature, and researchers need to prioritize pressing research questions to promote safe and healthy youth sport participation. The American Medical Society for Sports Medicine hosted a Youth Early Sport Specialization Summit in April 2019 with the goal of synthesizing and reviewing current scientific knowledge and developing a research agenda to guide future research in the field based on the identified gaps in knowledge. This statement provides a broad summary of the existing literature, gaps and limitations in current evidence, and identifies key research priorities to help guide researchers conducting research on youth sport specialization. Our goals are to help improve the quality and relevance of research on youth sport specialization and to ultimately assure that opportunities for healthy and safe sport participation continue for all youth.

Leveraging implementation science to prevent and reduce musculoskeletal overuse injury in musicians: A proposal for the study of a conceptual framework.

BACKGROUND: Musician health and wellness, a fundamental requirement for safe, effective and optimal musical performance, is not guaranteed. Performance related musculoskeletal disorders (PRMD) affect between 60% and 90% of all musicians, and have serious consequences on musculoskeletal health, performance ability and the overall healthcare burden of musculoskeletal injury. The high prevalence of PRMD in musicians can be prevented and reduced via health-education programs designed to address risk factors and practice habits. Multiple studies demonstrate the efficacy of education and instructional exercises in reducing PRMD symptoms in musicians. Despite the awareness of risk and the substantial consequence of non-adherence, implementation of health-education programs is complex and challenging and is rarely offered in music institutions. For successful adoption of musculoskeletal health programs, it is important to identify system level barriers and facilitators and it is important to develop and pilot effective strategies to guide successful implementation of musculoskeletal health programs for musicians. PURPOSE: This paper proposes a conceptual framework using implementation science methodology to study the factors that influence adoption of musician health education programs to prevent performance related injury. The overall goal of this methodology is to identify determinants of implementation by engaging key stakeholders, developing strategies for adoption of injury prevention programs and generate hypotheses for future studies. METHODS: The research plan is designed to accomplish the specific aims of this study. Through a mixed-method study we will use qualitative and quantitative methods to address potential barriers, and design and test implementation feasibility of health-education programs for musicians. RESULTS/CONCLUSIONS: Our findings will inform the development of a large-scale participant randomized hybrid trial to assess effectiveness and implementation outcomes of health education programs and ultimately reduce injury and promote musculoskeletal longevity and performance in musicians.

Forty-five per cent lower acute injury incidence but no effect on overuse injury prevalence in youth floorball players (aged 12-17 years) who used an injury prevention exercise programme: two-armed parallel-group cluster randomised controlled trial.

OBJECTIVE: To study whether an injury prevention exercise programme would reduce the number of injuries in youth floorball players. METHODS : 81 youth community level floorball teams (48 clusters=clubs) with female and male players (12-17 years) were cluster-randomised into an intervention or control group. Intervention group coaches were instructed to use the Swedish Knee Control programme and a standard running warm-up before every training session, and the running warm-up before every match, during the season. Control teams continued usual training. Teams were followed during the 2017/2018 competitive season (26 weeks). Player exposure to floorball and occurrence of acute and overuse injuries were reported weekly via a web-based player survey using the Oslo Sports Trauma Research Centre Questionnaire. RESULTS : 17 clusters (301 players) in the intervention group and 12 clusters (170 players) in the control group were included for analyses. There were 349 unique injuries in 222 players. The intervention group had a 35% lower incidence of injuries overall than the control group (adjusted incidence rate ratio (IRR) 0.65, 95% CI 0.52 to 0.81). The absolute risk reduction was 6.6% (95% CI 3.2 to 10.0), and the number needed to treat was 152 hours of floorball exposure (95% CI 100 to 316). Intervention group teams had a 45% lower incidence of acute injuries (adjusted IRR 0.55, 95% CI 0.37 to 0.83). There was no difference in the prevalence of overuse injuries (adjusted prevalence rate ratio 0.96, 95% CI 0.73 to 1.26). CONCLUSION : The Knee Control injury prevention programme reduced acute injuries in youth floorball players; there was no effect on overuse injuries. TRIAL REGISTRATION NUMBER: Clinical Trials NCT03309904.

Injuries in elite women's ski jumping: surveillance through the 2017-18 FIS World Cup season.

OBJECTIVES: To describe the incidence, type, aetiology and severity of injuries sustained by the International Ski Federation World Cup level female ski jumpers during the 2017-18 season. DESIGN: Prospective cohort study. METHODS: Sixty-seven female ski jump athletes from 16 countries were followed throughout the 17-week winter season. Preseason baseline demographic data and injury history were recorded via questionnaire. Prospective biweekly reports and retrospective end-of-season interviews provided data on all injuries requiring medical attention. RESULTS: Seventeen injuries were recorded, corresponding to an incidence of 25.4 injuries/100 athletes/season. The incidence of time-loss and severe injuries were found to be 17.9 and 4.5, respectively. The knee was the most common site of injury (4/17; 23.5%). Fourteen injuries occurred on the ski jump hill and crash-landing was the most common mechanism of injury (10/14; 71%). Eighty-five per cent of all moderate and severe injuries occurred in snow or windy conditions. Length of jumps resulting in injury averaged 83.7% (95% CI 72.9% to 94.4%) of hill size. Moderate injuries causing 8-28 days absence from training activities were most common (7/17; 41%) and there were three severe injuries necessitating >4 weeks absence. CONCLUSION: Injuries among elite female ski jumpers are common and the majority are acute, resulting in time loss from training and competition. The knee was the most common site of injury and poor weather conditions may be a risk factor. Future studies are needed to identify risk factors for injury and to guide injury prevention initiatives.

Exploring the potential utility of a wearable accelerometer for estimating impact forces in ballet dancers.

Excessive forces and/or loading rates during landing may place ballet dancers at risk for overuse injury. The ability to estimate and monitor the landing forces of ballet dancers could help to improve injury prevention and rehabilitation; however, force platforms are not conducive to testing outside of a laboratory. Fortunately, it may be possible to indirectly assess landing forces via a wearable accelerometer. The purposes of this study were to examine the relationship between impact accelerations, recorded via a pelvis-worn accelerometer, and the peak forces and loading rates during performance of a common ballet manoeuvre, and to examine if a wearable accelerometer is sensitive to fatigue-related changes in landing forces. Fifteen ballet dancers continuously performed a ballet manoeuvre until self-determined exhaustion while impact accelerations and landing forces were simultaneously recorded using an accelerometer and force platforms. We observed very strong, positive relationships between the impact accelerations and the peak forces and loading rates during the landings. In addition, the changes in impact accelerations with fatigue paralleled the changes in the peak forces and loading rates. As a result, it appears that a wearable accelerometer could be used to estimate and monitor landing forces in ballet dancers.

Preventing injuries among recreational adult volleyball players: Results of a prospective randomised controlled trial.

The objective was to evaluate the effectiveness of an exercise-based warm-up programme ("VolleyVeilig") on the one-season occurrence of musculoskeletal injuries among recreational adult volleyball players. A prospective randomised controlled trial was conducted over the 2017-2018 volleyball season. Recreational adult volleyball players were allocated either to an intervention or control group. The Dutch version of the Oslo Sports Trauma Research Centre questionnaire was used to register and monitor acute and overuse injuries. A total of 672 volleyball players were enrolled: 348 in the intervention group (mean age: 30) and 324 in the control group (mean age: 27). The incidence rate of acute injury was 21% lower in the intervention group, namely 8.9 versus 11.3 per 1,000 h in the control group (Cox mixed effects crude model: hazard ratio = 0.82 [95%CI: 0.69-0.98]; Cox mixed effects adjusted model: 0.85 [95%CI: 0.71-1.02]). No significant difference in mean prevalence of overuse injury was found between the intervention (4.8%) and control (4.2%) groups. The severity of injuries was not significantly different between groups, while injury burden was slightly lower in the intervention group. The exercise-based warm-up programme led to a trend in less acute injuries among recreational adult volleyball players.

Knowledge, Attitudes, and Beliefs of Youth Sports Coaches Regarding Sport Volume Recommendations and Sport Specialization.

Post, EG, Trigsted, SM, Schaefer, DA, Cadmus-Bertram, LA, Watson, AM, McGuine, TA, Brooks, MA, and Bell, DR. Knowledge, attitudes, and beliefs of youth sports coaches regarding sport volume recommendations and sport specialization. J Strength Cond Res 34(10): 2911-2919, 2020-Overuse injuries in youth athletes are becoming increasingly common, which may be a result of the prevalence of year-round specialized sport participation. Previous research has identified sport volume recommendations related to months per year, hours per week, and simultaneous participation in multiple sports leagues. Coaches are a primary influence on a youth athlete's decision to specialize in a single sport. Therefore, identifying coaches' baseline beliefs and perceptions is important for developing strategies to educate coaches about safe sport participation. A total of 253 youth sport coaches (207 males) completed an anonymous online questionnaire regarding knowledge of sport volume recommendations and attitudes and beliefs regarding sport specialization. Eligible participants were required to serve as a head or assistant coach of a youth sport team in the past 12 months whose members were between the ages of 12 and 18 years. Most coaches were unaware of recommendations regarding the maximum number of months per year (79.4%), hours per week in 1 sport (79.3%), or number of simultaneous leagues for an athlete to participate in to reduce injury (77.6%). Fewer than half (43.2%) of all coaches were "very" or "extremely" concerned about the risk of injury in youth sports. A majority (60.1%) believed that sport specialization was either "quite a bit" or "a great deal" of a problem. Two-thirds (67.2%) responded that year-round participation in a single sport was either "very" or "extremely" likely to increase an athlete's risk of injury. Although the responses to this survey were predominantly from coaches from 1 state, our results suggest that coaches are unaware of sport volume recommendations but are concerned about specialization. Future efforts are needed to communicate these recommendations to coaches to reduce the risk of overuse injury in youth sports.

Musculoskeletal Injuries Are Commonly Reported Among Gastroenterology Trainees: Results of a National Survey.

BACKGROUND: Endoscopy-related musculoskeletal injuries are increasingly recognized among gastroenterologists. While injury rates and risk factors have been studied among practicing gastroenterologists, little is known about rates among trainees during fellowship. AIMS: This study analyzes the prevalence of endoscopy-related overuse injuries and risk factors for injuries among a national sample of gastroenterology (GI) fellows. We also surveyed GI fellowship program directors and fellows about perceptions of overuse injuries during GI training. METHODS: We distributed a 29-item electronic survey to GI fellows at accredited programs in the USA in April 2016. Survey items included demographic information, questions pertaining to injuries, and level of agreement on the importance of ergonomics training in GI fellowship. Additionally, we distributed a 7-item electronic survey to fellowship program directors evaluating perception of overuse injuries and prevention during fellowship training. Fisher's exact test determined factors associated with sustaining an injury. RESULTS: An estimated 1509 fellows received the survey. Eleven percent (n = 165) of gastroenterology fellows completed the survey. Twenty percent reported having a musculoskeletal injury. Female gender was the only factor associated with a higher rate of reported injury (p < 0.01). The most common injuries reported were thumb and other hand-related pain (n = 28 [64%]). CONCLUSIONS: Musculoskeletal injuries may affect up to 20% of GI fellows. Female fellows more frequently report injuries and may be at particularly high risk which has not been found in previously reported surveys of practicing gastroenterologists. Standardized curricula on ergonomic considerations and injury prevention are needed to enhance GI fellowship training and reduce injury rates.

Self-regulatory skills: Are they helpful in the prevention of overuse injuries in talented tennis players?

Talented athletes use metacognitive skills to improve their performance. Also, it is known that these skills are important for managing one's health. The goal of this study was to identify the relationship between metacognitive skills and overuse injuries in talented tennis players. Metacognitive skills were measured in 73 talented tennis players (45 boys and 28 girls, age 11-14) at the start of the season, using the Self-Regulation of Learning Self-Report Scale. Overuse injuries were monitored for one season using the Oslo Sports Trauma Research Centre Questionnaire on Health Problems. Ordinal regression indicated that moderate or low selfmonitoring skills (compared to high selfmonitoring) (OR 4.555, CI 1.096-18.927, P = 0.037) and exposure time (OR 1.380, CI 1.106-1.721, P = 0.004) were associated with more time loss overuse injuries. A second analysis showed that this was the case in girls (OR 10.757, CI 1.845-62.714, P = 0.008), but not in boys. Linear regression revealed that higher reflection scores and exposure time predicted overuse severity (F(5,58) = 2.921, P = 0.020, R2  = 0.201). Possibly, selfmonitoring can help players to prevent themselves from time loss overuse injuries. Coaches should be aware that players can differ in selfmonitoring ability and thus in the ability to prevent overuse injuries. The role of reflection needs more research.

Apophysitis and Osteochondrosis: Common Causes of Pain in Growing Bones.

Apophysitis and osteochondrosis are common causes of pain in growing bones but have differing etiologies and required management. Apophysitis results from a traction injury to the cartilage and bony attachment of tendons in children and adolescents. Most often it is an overuse injury in children who are growing and have tight or inflexible muscle tendon units. Although apophysitis occurs in upper and lower extremities, it occurs more often in the lower extremities, with common locations including the patellar tendon attachment at the patella or tibia (i.e., Larsen-Johansson and Osgood-Schlatter diseases), the calcaneus (i.e., Sever disease), and multiple locations around the hip, including the anterior inferior iliac spine. Other locations include the medial epicondyle, which is common in patients who throw or participate in racket sports, and more rarely at the base of the fifth metatarsal (i.e., Iselin disease). Radiography can be helpful in evaluating for other pathologies but is usually not necessary. Treatment includes stretching the affected muscle groups, relative rest, offloading the affected tendon, icing after activity, and limited use of nonsteroidal anti-inflammatory drugs. Osteochondrosis presents less commonly and refers to degenerative changes in the epiphyseal ossification centers of growing bones. Unlike apophysitis, the etiology of osteochondrosis is unknown. Multiple possible etiologies have been explored, including genetic causes, hormonal imbalances, mechanical factors, repetitive trauma, and vascular abnormalities. Other locations of osteochondrosis include the second metatarsal head (i.e., Freiberg disease), the navicular bone (i.e., Köhler bone disease), the femoral head (i.e., Legg-Calvé-Perthes disease), and the capitellum (i.e., Panner disease). Radiography results may be normal initially; magnetic resonance imaging is more sensitive to early changes. Osteochondrosis generally resolves with relative rest, but close monitoring is needed to ensure resolution. Surgery is rarely needed for either apophysitis or osteochondrosis.

The effect of torsional shoe sole stiffness on knee moment and gross efficiency in cycling.

Altering torsional stiffness of cycling shoe soles may be a novel approach to reducing knee joint moments and overuse injuries during cycling. We set out to determine if the magnitude of three-dimensional knee moments were different between cycling shoe soles with different torsional stiffnesses. Eight trained male cyclists cycled at 90% lactate threshold power output in one of two cycling shoe conditions in a randomized crossover design. The shoe sole was considered torsionally flexible (FLEX) compared to a relatively stiffer (STIFF) sole. Gross efficiency (GE) and knee joint moments were quantified. No significant effect of shoe condition was seen in GE (21.4 ± 1.1% and 20.9 ± 1.6% for FLEX and STIFF, respectively, P = 0.12), nor in three-dimensional knee moments. 4 of the 8 subjects had reduced knee moments in at least 2 of the 3 moment directions. These "responders" were significantly shorter (1.73 ± 0.02 m vs 1.81 ± 0.04 m, P = 0.017) and had a higher relative maximal aerobic power (MAP) (4.6 ± 0.3 W∙kg-1 vs 3.9 ± 0.3 W∙kg-1, P = 0.024) compared to non-responders. These results suggest that certain shoe characteristics may influence certain individuals differently because these participants belong to different "functional groups"; certain individuals may respond positively to FLEX, while others may not. Further studies should test this proposed hypothesis.

Challenges of talent development in alpine ski racing: a narrative review.

Alpine ski racing is one of the most popular sports in many countries; nevertheless, selection disadvantages and severe injuries result in high dropout rates. In this review we summarize existing knowledge about the specific challenges associated with selection bias and injuries, and their effects on talent development in ski racing. The relative age effect (RAE) appears in all age categories of national Austrian and international alpine ski racing. Relatively younger athletes seem to only have a chance for selection if they are early maturing. Talent selection processes should consider both the biological maturity status as well as the relative age; additionally, a competition system based on a rotating cut-off date might contribute to a reduction of RAE. Youth and adolescent ski racers report lower injury rates compared to World Cup athletes. The knee was the most affected body part in relation to traumatic injuries. The most frequently reported overuse injuries were knee pain (youth) and low back pain (adolescent level). Athlete-related modifiable risk factors were core strength, neuromuscular control, leg extension strength and limb asymmetries. Based on these findings, prevention measures should be expanded to contribute to long-term injury prevention. In future research more multi-disciplinary, longitudinal studies should be performed.

Injury incidence in semi-professional football claims for increased need of injury prevention in elite junior football.

PURPOSE: Injuries are a common occurrence in football. Sufficient epidemiological data are available in professional football but not in salaried semi-professional football. This study investigates the injury incidence at different levels of semi-professional football with focus on junior football. METHODS: The data were based on injury reports provided by players and medical staff over the 2015-2016 season, which corresponded to the consensus statement for data samples in football. This study investigated the injury incidence and prevalence of five skill levels of semi-professional football (the fourth to the seventh league and elite junior football). RESULTS: 1130 players had sustained 2630 injuries over the 2015-2016 season. The overall injury incidence was 9.7 per 1000 h football exposure; prevalence with at least one injury was 79%. The highest overall injury incidence in elite junior football was 10.4 in 1000 h football exposure. The fifth league had the lowest incidence with 9.0 in 1000 h football (p < 0.05). Traumatic injuries most often occurred in the fourth league (3.9 in 1000 h football). The body areas most affected by traumatic injury were knees, ankles and thighs. Elite junior players had a significantly higher incidence of overuse complaints (7.4 in 1000 h football) than the fourth league (5.4, p = 0.005). The body areas most affected by overuse complaints were the lower back, thigh and groin. No differences were found between the different positions on field. CONCLUSIONS: Salaried semi-professional football involves a high overall injury incidence. The highest incidence, particularly of overuse injuries, was seen in elite junior football. These findings should be incorporated in specific injury prevention training or screenings beginning in junior football. Level of evidence II.

Algorithmically detectable directional changes in upper extremity motion indicate substantial myoelectric shoulder muscle fatigue during a repetitive manual task.

Repetitive workplace tasks are associated with fatigue-induced changes to shoulder muscular strategies, potentially altering kinematics and elevating susceptibility to tissue overexposures. Accessible and reliable methods to detect shoulder muscle fatigue in the workplace are therefore valuable. Detectable changes in joint motion may provide a plausible fatigue identification method. In this investigation, the onset of the first kinematic changes, as identified by a symbolic motion representation (SMSR) algorithm, and the onset of substantial surface electromyography (sEMG) mean power frequency (MPF) fatigue were not significantly different, both occurring around 10% of task duration. This highlights the potential utility of SMSR identified directional changes in joint motion during repetitive tasks as a cue of substantial muscle fatigue, enabling ergonomics responses that can mitigate shoulder muscular fatigue accumulation and its associated deleterious physical effects. Practitioner Summary: The onset of substantial muscle fatigue during a repetitive dynamic task was assessed using kinematics and myoelectric-based techniques. Algorithmically detectable directional changes in upper extremity joint motion occurred with the onset of substantial muscle fatigue, highlighting the potential of this as a useful approach for workplace fatigue identification.