bluuebunny/crossref_metadata_2025 huggingface dataset:
HOW MUCH RUGBY IS TOO MUCH? A SEVEN-SEASON PROSPECTIVE COHORT STUDY OF MATCH EXPOSURE IN PROFESSIONAL RUGBY UNION PLAYERS
Authors: Williams Sean , Trewartha Grant , Kemp Simon , Brooks John , Fuller Colin , Taylor Aileen , Cross Matt , Shaddick Gavin , Stokes Keith
Published: August 2017

Background

Player welfare concerns have been raised by a number of professional Rugby Union stakeholders regarding the match exposure demands faced by players.

Objective

To investigate the influence that acute and chronic match exposures have upon injury risk.

Design

A seven-season (2006/7–2012/13) prospective cohort design was used to record time-loss injuries (>24 h) and match exposure.

Setting

English Premiership Professional Rugby Union.

Participants

1253 professional players.

Assessment of Risk Factors

A player's 12-month match exposure (number of matches a player was involved in for ≥20 mins in the preceding 12 months) and month match exposure (number of full-game equivalent matches in preceding 30 days) were assessed as ‘chronic’ and ‘acute’ risk factors, respectively.

Main Outcome Measurements

A nested-frailty model was applied to calculate adjusted hazard ratios (HR) for the assessed risk factors. Thresholds for beneficial and harmful effects were 0.90 and 1.11, respectively.

Results

12-month match exposure was associated with injury in a non-linear fashion, with players who had been involved in less than ≈15 or greater than ≈35 matches (for ≥20 mins) over the preceding 12-month period being more susceptible to injury. Monthly match exposure was linearly associated with injury (HR: 1.14 per 2-SD increase, 90% CI: 1.08–1.20; likely harmful), although this effect was substantially attenuated for players in the upper quartile for 12-month match exposure (>28 matches).

Conclusions

A player's accumulated and recent match exposure substantially influences their current injury risk. Careful attention should be paid to planning the workload and monitoring the responses of players involved in: 1) a high number of matches in the previous year; 2) a low number of matches in the previous year; 3) a low-moderate number of matches in the previous year but have played intensively in the recent past. These findings could inform match workload planning in professional Rugby Union.
SERUM ANDROGEN PROFILE, BODY COMPOSITION AND PHYSICAL PERFORMANCE IN FEMALE OLYMPIC ATHLETES
Authors: Lindgren Emma Berglund , Berglund Bo , Hirschberg Angelica Lindén
Published: August 2017

Background

Androgens have anabolic effects that may contribute to enhanced physical performance and a decreased risk of injury in athletes. The role of endogenous androgens for athletic performance in female athletes is not yet fully elucidated.

Objective

To examine the profile of serum androgens in relation to body composition and physical performance in female Olympic athletes and compared to sedentary controls.

Design

Cross-sectional study, recruitment 2011–2015.

Setting

The Women's Health Research Unit, Karolinska University Hospital.

Participants

106 female Swedish Olympic athletes (summer and winter sports) and 117 controls (maximum 2 hours training per week, no prior participation in elite-level sports).

Assessment

Participants were examined at one occasion at rest and in a fasting state for blood sampling. Serum androgen levels were established by liquid chromatography-mass spectrometry. Body composition was evaluated by DXA. Physical performance tests (Squat jump (SJ), Counter Movement Jump (CMJ)) were made at the Sports Institute, Bosön, as part of the “Physical Profile” offered by the Swedish Olympic Committee.

Main Outcome Measurements

The profile of serum androgens, body composition, physical performance.

Results

Female Olympic athletes demonstrated significantly higher androgen levels of dehydroepiandrosterone (DHEA) and androstandiol (5-ADIOL), lower levels of estrone, and a more anabolic body composition compared to controls. Athletes in power sports had significantly higher bone mineral density compared to endurance and technical athletes, whereas endurance athletes had the highest values of lean mass. Serum levels of DHEA and 5-ADIOL correlated positively to lean mass in female athletes (R=0.25–0.33). Furthermore, DHEA, 5-ADIOL and dihydrotestosterone correlated positively to CMJ and SJ in the athletes (R=0.27–0.39).

Conclusions

We suggest that endogenous androgens contribute to a more anabolic body composition and increased physical performance in female athletes. Furthermore, the anabolic effect on body composition could play a role for the risk of injury.
FOOT POSTURE AND ITS RELATIONSHIP WITH KNEE KINEMATICS IN BAREFOOT RUNNING OF THE HEALTHY ADULT
Authors: Wong Trina , Paton Bruce
Published: August 2017

Background

Abnormal dynamic knee moments and variations of static foot posture are risk factors for chronic lower limb injury development. However, relationships between the two have yet to be established in the running gait.

Objective

The primary aim was to investigate the correlation between variations in static foot posture and maximum knee adduction. Secondary aims investigated the correlation of static foot posture with variables that affected dynamic knee motion.

Design

A single-group prospective exploratory study design was implemented.

Setting

Laboratory-based study setting.

Participants

23 volunteers from University College London social media network(n=3119) recruited in June 2016 met entry criteria of healthy adult 18–59 years) with no lower limb musculoskeletal injury in the last 6 months, history of biomechanical abnormality(including use of prosthesis) or lower limb surgery. All participated and completed study but only 14 sets of data were included due to data-corruption. Ana priorisample size calculation determined that 9–14 participants were required to demonstrate significantly different correlations(α=0.05, β=0.20).

Assessment of Risk Factors

Foot Posture Index scores of each participant's dominant foot was an independent variable during a 13 minute barefoot treadmill gait analysis.

Main Outcome Measurements

Maximum knee adductor moments, knee tri-planar kinematics, hip tri-planar kinematics, maximum loading force and foot-strike pattern were measured at 3 instances(1.39 m/s; 3.6 m/s; self-selected running speed) as determined prior to data-collection.

Results

No significant correlation (p<0.05) was found between static foot posture measurements and all outcome variables once confounders were accounted for. When comparing maximum knee adductor moments between the 3 speeds, significant correlations were observed (r=0.66–0.71, p<0.01).

Conclusions

In the healthy population, static foot posture and dynamic knee motion demonstrate a poor and insignificant relationship. Dynamic motion should be assessed independently in predicting future injury where more evidence is needed to account for variations in knee adductor moments.
INJURY INCIDENCE IN CROSS-COUNTRY SKIERS
Authors: Worth Sonya , Reid Duncan , Henry Sharon
Published: August 2017

Background

Prospective, cross-country ski injury incidence data is scarce.

Objective

To describe injury type and incidence sustained by elite cross-country skiers in north-eastern America. We hypothesized that lower extremity injury incidence would be higher than other body regions. A secondary aim was to determine any factors that correlate with new injury.

Design

A prospective, longitudinal study that included: demographics (ski and injury history); Movement Competency Screening (MCS); hamstring length measurement; core muscle endurance testing (trunk flexor to extensor ratio). Athletes then completed 12 consecutive, monthly electronic surveys about training, racing, and injury status.

Setting

Collegiate and professional ski team practices.

Patients (or Participants)

A convenience sample of 71 cross-country skiers (age 18–27 years, 35 men); 41 participants (18 men) completed the study.

Independent variables

MCS score; hamstring length; ratio of trunk flexor to extensor endurance; injury history; training activities and hours; training lost to injury.

Main Outcome Measurements

New injury reports.

Results

Mean injury incidence was 3.81 new injuries per participant, per 1,000 hours of training. Injury incidences for lower extremity (2.13), and overuse/non-traumatic (2.76) injuries were significantly greater than trunk (0.22), upper extremity (0.46), or acute/traumatic (1.05) injuries (p<0.05). Off-season injury incidence (5.25) was higher than during ski season (2.27), but not significantly (p=0.07). New injury positively correlated with past injury (p=0.04) and also increased as monthly running time increased but not significantly (p=0.08). New injury did not correlate with: MCS score; hamstring length, or; core ratio (p>0.05). Past injuries were a significant predictor of new injuries, when accounting for training time, running time and MCS score (p<0.05).

Conclusions

This year long, prospective report of injury type and incidence in competitive cross-country skiers demonstrated that lower extremity and overuse/non-traumatic injuries had the highest incidence rates. Previously injured skiers are at greater risk of further injury.
SPINE DISEASE PREVENTION IN TECHNICAL SPORTS
Authors: Zelenkova Irina , Zotkin Sergey , Almiashev Dmithry , Savin Dmithry
Published: August 2017

Background

Rally raid is a form of long distance off-road racing that takes place over several days. Injuries and spine disease related to the high speed and off-road profile of the track are common in these athletes.

Objective

To examine the effect of a program of functional training implemented in the yearly preparation cycle on the risk of spine injury.

Design

Prospective intervention study, without control group.

Setting

Professional rally raid.

Patients (or Participants)

16 male professional truck drivers (177 (176–182) cm, 82.4 (75.4–85.6) kg, body mass index 25.4 (24.6–26.8) kg/m2, 32.5 (29.0–39.5) yrs), all high achievers with regular participation in rally raids.

Intervention

An exercise program was prescribed from Oct 2014 to Dec 2015 which included six separate 3-week blocks of training (six days of training with 1 day off in each block).

Main Outcome Measurements

Analysis of radiological parameters: the formation of new hernia or impairment of current state of disc protrusion, radicular symptoms, Modic changes, hernia types, subchondral sclerosis according to Grogan classification, Pfirrmann grade. Muscle endurance was also tested in the plank position.

Results

An increase in muscle endurance was observed in all athletes (p>0.05). Compared to the 2013–2014 season, in 2015 no new hernias or radicular symptoms were registered. Disk protrusions also did not increase in 2015, compared to 2013/14.

Conclusion

There was no deterioration in radiological changes and an improved trunk muscle endurance after the introduction of a functional training program, documenting the importance of functional training in motor sports.
THE IMPACT OF RUNNING INJURIES IN RELATION TO OTHER REASONS FOR DISCONTINUED RUNNING IN NOVICE RUNNERS
Authors: Bertelsen Michael Lejbach , Rasmussen Sten , Nielsen Rasmus Østergaard
Published: August 2017

Background

The risk of running injuries in novice runners is 17.8 (16.7–19.1) per 1000 h of running (Videbæk 2015). This might lead to the conclusion that running injuries are one of the main reasons for discontinued running. However the impact of running injuries in relation to other reasons for discontinued running remains to be investigated.

Objective

To investigate the proportion of novice runners that sustained an injury before discontinuing running.

Design

Observational prospective cohort study with a 1-year follow-up.

Setting

Novice runners.

Participants

930 healthy novice runners, age 18–65, with less than 10 km of total running volume during the past year and no injury in the lower extremities or back 3 months preceding baseline.

Interventions

The participants were equipped with a GPS watch and running shoes and instructed to upload their running to a web-based diary during the 1-year follow-up. They could keep the shoes and watch if they completed a total of 52 training sessions or more.

Main Outcome Measurements

Discontinued running dichotomized (i) yes still running (ii) no training uploads for the remainder of the 1 year follow up (defined after data collection began), whereas the latter, was further dichotomized into (i) injured (a priori defined as 1 week time loss definition) (ii) injury free.

Results

A total of 9% (7%–11%) had discontinued running after 90 days. Of these, 20% (11%–29%) had sustained a running injury. After 180 days the proportion discontinuing rose to 16% (14%–18%). Amongst these 16%, injured accounted for 24% (17%–31%). Finally, after 270 days the proportion who discontinued was 27% (24%–30%), with an injury proportion of 23% (18%–28%).

Conclusions

Running injuries are common in novice runners who discontinue running. The developments of injury prevention strategies are important if more inactive persons should be successfully included in running.
EPIDEMIOLOGY AND INCIDENCE OF INJURY IN ELITE NETBALL PLAYERS – AN INJURY AUDIT OF THE 2016 NETBALL SUPERLEAGUE SEASON
Authors: Best Gemma
Published: August 2017

Background

With England netball announcing that for the first time in its history it will be offering full time, professional contracts there is an increased need to be able to understand why players are getting injured in top level competition.

Objective

To undertake a prospective epidemiological study of injuries sustained in elite netball.

Design

A cohort design was used to collect descriptive injury data using superleague netball players.

Setting

2016 British Netball Superleague season.

Patients (or Participants)

103 players across 8 superleague netball teams were used in the study.

Main Outcome Measurements

Date of injury, age of player, playing position, activity at time of injury, mechanism of injury, classification of injury at two levels (body location and injury type), predicted time loss and identification of injury being acute, gradual on set or recurrent was recorded. Injuries were recorded by physiotherapists at each netball franchise using a specific injury audit questionnaire designed to suit the characteristics of netball.

Results

59 injuries we recorded during one season with an injury incidence rate of 9.08 injuries per 1000 hours exposure. Injuries were more common in competitive match play (71.2%) than in training (28.8%). The ankle was injured most frequently (35.6%). Data revealed a significant association between match quarter and occurrence of injuries χ2(3)=9.91, p=0.019. A tendency for injuries to increase throughout the time in match and a peak reached at the third quarter was observed. No significant association was observed between playing position and injury incidence χ2(2)=0.917, p=0.632. Overall injury frequency was highest in the first half of the regular 14 week season with 57.6% of all injuries occurring in this time frame.

Conclusions

Pre-season preparation, half time match strategies and overall physiological conditioning should be considered when addressing injury prevention within elite netball.
THE RELIABILITY OF TWO-DIMENSIONAL (2D) BIOMECHANICAL VARIABLES DURING MULTIDIRECTIOANAL SINGLE LEG LANDING
Authors: Alahmari Ahmed , Herrington Lee , Jones Richard , Liu Anmin , Neamatallah Ziyad
Published: August 2017

Background

The knee joint is one of the most frequently injured joint in sports. Sport injury is mostly non-contact in nature and often occur during single leg landings (SLL). SLL are also a common task performed in many sports. The reliability of different landing tests has been examined in the literature, but mostly limited to one test and most studies did not report the standard error of measurement (SEM) of their measurement. Although three-dimensional (3D) motion analysis is the gold standard for examining lower limb biomechanics, its extension to a clinical setting or to a larger sample size is limited. Therefore, researchers have examined 2D motion analysis and found it a good alternative.

Objective

To establish the reliability and SEM of a 2D movement analysis system to measure the kinematics of lower extremity during multidirectional SLL.

Design

Test-retest reliability study.

Setting

University laboratory.

Patients (or Participants)

12 moderately active university students.

Assessment of Risk Factors

2D knee and hip frontal plane kinematics were collected for both legs while the subjects performed multidirectional SLL. A retest session was repeated one week later.

Main Outcome Measurements

Frontal plane projection angle (FPPA) and hip adduction angle.

Results

The ICC for the different variables ranged between 0.67 and 0.96, indicating good to excellent reliability for all 2D variables in all tasks. SEM ranging between 0.69° and 2.7° which can be an evidence for small measurement error.

Conclusions

The 2D biomechanical variables were reliable when examining multidirectional SLL tasks in a moderately active healthy population. Furthermore, multidirectional SLL is a reliable test to examine the lower extremity biomechanics.
INJURIES IN GERMAN MEŃS PROFESSIONAL ICE HOCKEY
Authors: Bloch Hendrik , Klein Christian , Luig Patrick
Published: August 2017

Background

Injury incidences during international major ice hockey events are high, but information about ice hockey injuries in Germany, particularly in regular league play, is lacking.

Objective

Analysis of injury characteristics in German professional ice hockey.

Design

Prospective observational cohort study.

Setting

Two highest German professional leagues in men's ice hockey.

Participants

All first and second division ice hockey players who played at least in one competitive club match during the season 2014/15 season (n=812).

Assessment of Risk Factors

Analysis of all injuries of these players that were registered by clubs or physicians with the VBG as a part of the occupational accident reporting and that either led to the player's short-term disability (time-loss) and/or to medical treatment costs (medical-attention).

Main Outcome Measurements

Injury prevalence and incidence, injured body parts, type of injury, medical treatment costs, days of absence.

Results

A total of 2.045 injuries were recorded. 76.7% of all players were injured at least once. In mean each player had 2.52 injuries per season. Incidence rate in the first division (2.7 injuries/season) was significantly higher than in second division (2.3 injuries/season). The majority of injuries (69.1%) occurred during matches with a match incidence of 136.8 injuries per 1000 h. Nearly one third (30.7%) of all training injuries occurred during the pre-season. The head (17.9%), the shoulder (10.7%) and the thigh (10.1%) were the body parts most frequently affected. Shoulder injuries lead to the highest share of overall time-loss (20.5%) and medical treatment costs (22.0%). Goalkeeper had significant lower overall risk of injury (1.5 injuries/season), but higher risk of knee and thigh injuries.

Conclusions

Injury Risk in German professional ice hockey is high, especially during match play. Preventive measures should aim at sport- and position-specific risk factors. Special focus should be laid on player preparedness after off-season break.
IMPACT OF THE NORDIC HAMSTRING AND HIP EXTENSION EXERCISES ON HAMSTRING ARCHITECTURE AND MORPHOLOGY: IMPLICATIONS FOR INJURY PREVENTION
Authors: Bourne Matthew , Duhig Steven , Timmins Ryan , Opar David , Williams Morgan , Kerr Graham , Shield Anthony
Published: August 2017

Background

There has been significant interest in exploring the patterns of muscle activity in hamstring exercises, however, there is no research examining the architectural and morphological adaptations of these muscles to different exercise interventions.

Objective

To evaluate changes in biceps femoris long head (BFLH) fascicle length and hamstring muscle size following Nordic hamstring exercise (NHE) or hip extension (HE) training.

Design

In this longitudinal study, participants were randomly allocated to one of three groups: 1) HE training (n=10), NHE training (n=10), or no training (CON) (n=10). BFLHfascicle length was assessed before, during (Week 5) and after the intervention with 2D-ultrasound. Hamstring muscle size was determined before and after training via magnetic resonance imaging.

Setting

Laboratory based.

Patients (or Participants)

Thirty recreationally active males (age, 22.0±3.6 years, height, 180.4±7 cm, weight, 80.8±11.1 kg).

Intervention

A 10-week progressive intensity strength program consisting exclusively of NHE, HE training, or a period of no training.

Main Outcome Measurements

BFLHfascicle length and hamstring muscle volumes.

Results

Compared tobaseline, BFLHfascicles were lengthened in the HE and NHE groups atmid-(d=1.12–1.39, p<0.001) andpost-training(d=1.77–2.17, p<0.001) with no difference observed between training groups (d=0.49–0.80, p=0.279–0.976). BFLHvolume increased more for the HE than the NHE (d=1.03, p=0.037) and CON (d=2.24, p<0.001) groups. Compared to the CON group, both exercises induced significant increases in semitendinosus volume (d=2.16–2.50, ≤0.002) which were not significantly different (d=0.69, p=0.239).

Conclusions

NHE and HE training both stimulate significant increases in BFLHfascicle length, however, HE training may be more effective for promoting hypertrophy in the BFLH.
INDIVIDUAL PHYSICAL MONITORING FOR ELITE WOMEN'S INTERNATIONAL SOCCER PLAYERS: AN EDUCATIONAL PROGRAMME
Authors: Boyce Stephen , Davies Oliver , McKenna Michael , White Andrew , Dixon Mark , Elliott Niall
Published: August 2017

Background

Education of soccer players is important in injury prevention and maintaining health throughout their career. Injury epidemiological studies have highlighted risk around knee and ankle. Aetiological factors include direct trauma, biomechanical imbalances, poor mobility, strength imbalances and training load.

Objective

To monitor individual player specific physical range of movement scores to inform and educate players around self-management, readiness to train and injury risk.

Design

Prospective observational study.

Setting

Scotland women's soccer national squad.

Participants

Elite women international soccer players.

Interventions (or Assessment of Risk Factors)

Players were assessed each morning during international team camps for a range of objective physical markers.

Main Outcome Measurements

Sit and reach distance, Knee to wall distance, Thomas test hip range of movement. Average scores were used to educate players and individually tasked with completing specific self-management modalities to improve these scores before entering a risk environment.

Results

28 players completed the self-directed objective tests. The physical markers were averaged out and players given individual red, amber and green scores. The markers were discussed amongst the sports medicine team and concerns regarding a player's health and fitness relayed to the coaching staff. The player was tasked with completing self-directed individualised exercises to improve any flagged scores. They were also tasked with completing this in their club environment and improvement in physical markers scores was noted on subsequent camp entries.

Conclusions

Using specific physical markers individual to each player we were able to track and inform of any flagged scores during the health check. This enabled us to give a clear understanding of player readiness to train as well as informing and educating the player on how they could improve their scores through self-management modalities therefore decreasing injury risk. Initial findings through injury surveillance suggest a decrease in lower limb muscle related injuries.
GENGHIS KHAN ICE MARATHON: PREPARATION, STRATEGY AND THE EFFECT OF EXERCISE IN AN EXTREME COLD ENVIRONMENT IN A GROUP OF EXPERIENCED ULTRARUNNERS
Authors: Boyce Stephen , Murray Andrew , Scott David
Published: August 2017

Background

The Genghis Khan Ice Marathon took place in January 2016 in the mountains of the Terelj National Park, Mongolia in a temperature of minus 350C.

Objective

To assess the experience, preparation, race strategy and effect of exercise in a group of ultrarunners undertaking a marathon in extreme cold.

Design

Prospective observational study.

Setting

Extreme environment.

Participants

Multinational group of experienced ultrarunners (n=9, male 5, female 4, age range 25–53 years).

Interventions

Pre and post race questionnaires. Post-race email surveillance.

Main Outcome Measurements

Experience, preparation, clothing, equipment, nutritional strategies for race. Adverse effects encountered when competing in the marathon. Perceived effort of race on the Borg Scale. Two weeks post race illness or injury surveillance.

Results

All nine ultrarunners completed the questionnaires and follow up. Concerns about safety in a remote environment were universal. Consensus was present regarding clothing, equipment, hydration and nutrition. The race was completed in 3:05–5:50. No significant difficulties were encountered. The cold air caused freezing around the nostrils and irritated the airways. No-one experienced cold induced bronchospasm. Clothing froze due to sweat and expired air. There were no cases of hypothermia. There were two cases of frostbite; earlobe (moderate) and nose (mild). Borg scale of perceived exertion values ranged from 13–17 (mean 15). Two week follow up; two cases of viral URTI's reported. No athlete reported DOMS in the post race period.

Conclusions

All athletes were experienced in ultrarunning. They shared concerns regarding competing in a remote, extreme cold environment. All were adequately prepared pre race in terms of clothing, equipment and race nutrition strategy. This level of experience contributed to the lack of complications during the race and in the post race period. No athletes experienced DOMS presumably related to lack of peripheral muscular perfusion during exercise in extreme cold.
HOW IMPORTANT IS KNEE POSITION ON LANDING FOR ANKLE SPRAIN?
Authors: Castro Maria António , Fernandes Orlando , Janeira Manuel António , VencesBrito António
Published: August 2017

Background

In sports ankle sprains are responsible for most of the time lost in practice. In basketball, ankle sprains are not only a main injury but they also have a high tendency of re-injury. There is a special interest in finding risk factors that can be used to predict the ankle sprain occurrence and so prevent it. Joint position when contacting the ground is a main issue.

Objective

The aim of this study is to examine the knee position on ground contact moment and its relationship with ankle sprain.

Design

To reproduce the most common mechanism of ankle sprain in basketball players, landing in another player's foot, barefoot athletes with healthy (n=17) and already sprained ankles (n=28) were asked to jump from the floor to an unstable round surface placed 50 cm in front of them while kinematics was recorded using an electromagnetic tracking device with 3 sensors located in each segment of the lower limb and another on a round Freeman board.

Setting

elite basketball players.

Patients (or Participants)

13 females, and 12 males accepted to perform five consecutive jumps in unipodal support.

Interventions (or Assessment of Risk Factors)

Previous ankle sprain or never sprained ankle.

Main Outcome Measurements

Knee range of motion on landing.

Results

At contact knee angles did change significantly with previous ankle sprain. Never sprained subjects showed more knee flexion on contact. When separating results by gender we found that women landed with knees in an even more extension degree.

Conclusions

Knee position on landing differs from healthy to previous sprained ankles. Previous sprained land in a more extension position and consequently a higher impact energy for lower limb and all the body must be absorbed. This difference is even more important among females.
THE PROTECTIVE EFFECTS OF VARIOUS WARM-UP MODALITIES ON EXERCISE-INDUCED BRONCHOSPASM (EIB) IN NON-ASTHMATIC ATHLETES
Authors: Chang Jae Seung , Lee Young Hee , Kong In Deok
Published: August 2017

Background

Exercise-induced bronchospasm (EIB) that is a transient airway obstruction occurring after strenuous exertion can occur in non-asthmatic athletes as well. However acute effects of different warm-up modalities on EIB in athletes without asthma remain uncertain.

Objective

The aim of this study was to determine the efficacy of different warm-up modalities on improving EIB in non-asthmatic athletes.

Design

Randomized crossover controlled trial. Each participant performed four experimental trials on nonconsecutive days, consisting of exercise challenge test for 6 min (at velocity of 90%HRmax) following either continuous warm-up (CW), high-intensity interval warm-up (HW), modified warm-up (MW) or no warm-up (NW). Pulmonary functions were measured prior to each experimental trial, and repeated before and at 1, 5, 10, 15, 20 min after exercise challenge.

Setting

Research laboratory in a university setting.

Participants

Eleven competitive collegiate athletes.

Interventions

CW consisted of 15-min run at a velocity corresponding to 60%VO2max, HW involved 8 repetitions of 30-sec run (45-sec rest between bouts of running) at an intensity equivalent to 90–100%VO2max, and MW was composed with combination of HW (6 repetitions) and CW (5-min).

Main Outcome Measurements

The main spirometric parameters of airway obstruction included forced expiratory volume in 1 second (FEV1.0), forced vital capacity (FVC), and their ratio (FEV1.0/FVC), forced mid-expiratory flow (FEF25–75) and peak expiratory flow (PEF).

Results

The mean maximum percent fall in pre- to post-exercise FEV1.0for all subjects during the EIB screening test was −17.7±6.5%. The mean maximum percent decrease in post-exercise FEV1.0significantly decreased to −4.0±5.5% and −5.2±3.5% following CW and MW, respectively (allp<0.01). All of three warm-up modalities significantly attenuated the mean percentage fall in FEV1.0at 5, 10 and 15 min compared to control (allp<0.05).

Conclusions

These data indicate that all of three warm-up modalities have a protective effect against developing EIB in non-asthmatic athletes.
EFFECTS OF REDUCED PLANTAR CUTANEOUS SENSATION ON GAIT KINEMATICS IN INDIVIDUALS WITH OR WITHOUT CHRONIC ANKLE INSTABILITY
Authors: Chang Mi Hyang , Kang Tae Kyu , Lee Sae Yong
Published: August 2017

Background

Chronic ankle instability (CAI) is associated with repetitive lateral ankle sprains, exhibiting postural-control deficits and altered gait biomechanics. Plantar cutaneous receptors have been theorized to affect postural control, but their contribution to postural-control deficits shown in CAI group during walking is unclear.

Objective

To examine the effect of diminished plantar cutaneous sensation induced by cooling on gait kinematics in participants with or without CAI.

Design

Case-control study.

Setting

Laboratory.

Patients (or Participants)

Seven individuals with CAI (age: 23.57±2.72 years; height: 166.14±7.74 cm; weight: 67.84±12.60 kg) and 10 healthy controls (age: 23.4±2.15 years; height: 164.29±5.88 cm; weight: 59.16±9.66 kg).

Interventions (or Assessment of Risk Factors)

The plantar aspect of the participants' foot was submersed in ice water (0°C) for 10 minutes to induce hypoesthesia. Before and after the cooling procedure, plantar cutaneous sensation thresholds and walking trials were measured.

Main Outcome Measurements

3-dimensional lower extremity joint kinematics were recorded throughout the gait cycle. Group means and 95% confidence intervals were compared for percentages of the gait cycle where the confidence intervals did not overlap.

Results

With plantar hypoesthesia, CAI participants indicated less hip adduction from 5% to 70% (mean difference=3.44±1.66°) and more knee internal rotation from 32% to 54%(mean difference=11.78±0.74°), and from 88% to 100%(mean difference=8.65±0.91°) of the gait cycle compared to healthy controls. No significant interactions were found between sensation and groups for lower extremity gait kinematics during walking.

Conclusions

There was no significant effect of reduced plantar cutaneous sensation on gait kinematics in individual with or without CAI. The alterations in proximal joint kinematics can be a preservation strategy for individuals with CAI to complete normal ambulation. Our findings may explain that there are other factors contributing to altered proximal joint kinematics in CAI group during gait than plantar cutaneous sensation.
IMPLICIT AND EXPLICIT VIDEO FEEDBACK ON LANDING MECHANICS: A RANDOMIZED CONTROLLED TRIAL
Authors: Cortes Nelson , Popovic Tijana , Eddo Oladipo , Benjaminse Anne , Caswell Amanda , Caswell Shane
Published: August 2017

Background

Lower extremity(LE) patterns have been altered using implicit(IF) and explicit(EF) feedback motor learning strategies, however, it remains unclear which strategy may be more effective for injury prevention.

Objective

To examine the effects of reduced relative IF and EF video-feedback on LE biomechanics.

Design

Randomized Controlled Trial.

Setting

Recreational.

Participants

30 participants were randomly assigned to 3-groups: control (CG) (n=10, 24±2 years, 1.68±0.1 m, 68±14 kg), IF (n=10, 25±3 years, 1.72±0.1 m, 69±12 kg), and EF (n=10, 23±2 years, 1.74±0.1 m, 74±8 kg). Exclusion criteria: no LE injury 6-months prior to testing, no ACL reconstruction, and no history of participation in supervised LE injury prevention programs.

Interventions

Twelve drop-jumps were performed 3-times a week for 5 weeks. IF group focused attention on overall jump performance, whereas EF group focused attention on knee mechanics. 3D LE biomechanics were tested after 1-week (PST1), 2-weeks (PST2), and 5-weeks (PST3), and 1-month retention (RTN). Participants viewed 2-videos for sagittal and frontal planes, in normal speed and slow motion. Video-feedback was provided along a reduced feedback continuum partitioned into 100%, 33% and 16.6% feedback frequency phases.

Main Outcome Measurements

Linear mixed-effects models were conducted to assess group and time differences for peaks of hip abduction(HA°), knee abduction(KA°), and vertical ground reaction force(vGRF,N), p<0.05.

Results

No group-time interaction was found(p>0.05). Group effects were attained(p<0.05) for HA: IF was lower than EF and CG, and for KA, where PST3 was closer to neutral when compared to PST1. Time effect for vGRF(p<0.05) was observed: PST3 and RTN were lower than PST1.

Conclusions

Retention and retrieval of learned movement patterns seemed to follow identical attrition patterns. It is feasible to suggest that both motor learning strategies produced similar outcomes. Future research should expand the retention period and retrieval of learned skill movements to enhance the effectiveness of injury prevention programs.
THE INFLUENCE OF THE TIME SCALE USED IN TIME-TO-EVENT ANALYSES ON THE IDENTIFICATION OF TRAINING-RELATED RISK FACTORS IN RUNNING
Authors: Damsted Camma , Nielsen Rasmus Oestergaard , Malisoux Laurent
Published: August 2017

Background

Training errors are considered as one of the main causes of running-related injuries, although few of them have been identified. Time-to-event analysis is a useful tool for researchers within sports injury prevention. In running, the time scale is commonly defined as kilometres or hours of practice. However, using calendar days as time scale could also be relevant.

Objective

To determine the influence of the time scale on the association between cumulated running distance and injury risk.

Design

Observational study with a 6-month follow-up.

Setting

Leisure-time runners.

Participants

Study participants (n=553) were required to report any running activity and injury using a dedicated internet platform.

Assessment of Risk Factors

The main exposure was cumulated running distance over the week prior to a given session (time-dependent exposure) and was categorised as <20 km (reference group), between 20 and 30 km, and ≥30 km. Cox regression analyses were used to compare injury rates between exposure states, using either kilometres or calendar days as time scale.

Main Outcome Measurements

First running-related injury based on a 1-day time loss definition.

Results

A total of 93 of the runners reported at least one injury. When the time scale was kilometres at risk, the results revealed injury rate to be lower when the participants cumulated a higher running distance. Hazard ratios (HR) were respectively 0.52 (95% confidence intervals −95% CI=0.30–0.89) and 0.40 (95% CI=0.23–0.70) in the 20–30 km and ≥30 km exposure states compared with the reference. When the time scale was calendar days, these HR were respectively 1.38 (95% CI=0.80–2.38) and 1.83 (95% CI=1.12–3.00) for the same exposure states, which suggests that injury risk was higher when more kilometres were cumulated.

Conclusions

The choice of time scale revealed highly contrasting results, and has to be carefully considered in studies examining risk factors for running-related injuries.
THE IMPACT OF RUNNING LEVEL ON THE ASSOCIATION BETWEEN RUNNING DISTANCE AND INJURY RISK
Authors: Damsted Camma , Nielsen Rasmus Oestergaard , Malisoux Laurent
Published: August 2017

Background

Running distance has previously been identified as a risk factor for running-related injury. It is likely that the runner's fitness level may also influence injury risk.

Objective

To investigate if running level modifies the association between cumulated running distance over the previous week and injury risk.

Design

Prospective cohort study with a 6-month follow-up.

Setting

Recreational runners.

Participants

Injury free recreational runners (n=372) were required to report all running activity as well as any injury using a dedicated Internet platform.

Assessment of Risk Factors

The main exposure was cumulated running distance over the week prior to a given session (time-dependent exposure) and was dichotomized into low<20 km (reference group), and high≥20 km.Running level was defined as the average running speed during follow-up and was dichotomized into fast runners≥10 km/h and slow runners<10 km/h.

Main Outcome Measurements

First running-related injury based on a 1-day time loss definition.

Results

In the crude analysis, a lower injury rate was observed when the runners cumulated a high running distance prior to a given session (hazard ratio (HR)=0.43; 95% confidence interval (95% CI)=0.28–0.66). After stratification according to running level, a significant lower injury rate was found for slow runners (HR=0.32; 95% CI=0.18–0.60) when they cumulated a high running distance prior to a given session, while the injury rate did not differ between exposure states for fast runners (HR=0.78; 95% CI=0.37–1.64). Based on the hazard ratios from the stratified analysis, it appears that low running level modifies the association between cumulated running distance over the previous week and injury risk with a factor of 2.43.

Conclusions

Running level should be taken into account when analysing the association between training-related risk factor and injury risk.
VIDEO ANALYSIS OF ACUTE INJURIES DURING THE 24TH MEN'S HANDBALL WORLD CHAMPIONSHIP 2015 IN QATAR
Authors: Andersson Stig H. , Bahr Roald , Cardinale Marco , Popovic Nebojsa , Bere Tone , Myklebust Grethe
Published: August 2017

Background

Handball is a contact sport with a high prevalence of acute injuries. Injuries often occur during high-speed movements involving several players, making it difficult to describe the exact mechanism of injury.

Objective

Describe the mechanisms of injury in elite male handball.

Design

Prospective video analysis.

Setting

During the men´s handball world championship 2015, 132 injuries were reported through on-site injury surveillance by team medical staff. Based on the injury reports, two operators accessed the videos of each game and identified the specific injury situations using video analysis software (ProzoneHANDBALL v.1.0.0.14, ProzoneSports, Leeds, UK).

Video analysis

A total of 97 injury videos were identified; 42 were excluded, as the injury situation was not visible. Five handball experts performed an individual analysis of the 55 included videos based on a specific form developed to describe the injury situations and causes, followed by a consensus meeting.

Main Outcome Measurements

The form included variables related to the playing situation, landing situation, action of attacker and defender at time of injury and localization of tackle/hit.

Results

The most common injury location was the head and face (n=17, 31%), followed by the ankle (n=6, 11%). The most frequent injury cause was opponent contact (n=27, 49%), followed by landing trauma subsequent to opponent contact (n=8, 15%). The injuries were equally distributed between attackers (n=29, 53%) and defenders (n=26, 47%), but time-loss injuries (49%) were more common among attackers (68%). The most frequent playing action performed by injured attackers was a jump shot (n=9, 31%); tackles were most often to their throwing arm (n=7, 30%).

Conclusions

Acute injuries in elite male handball are equally distributed between attackers and defenders. However, attackers sustain more severe injuries. The most frequent injury causes are direct opponent contact and landing trauma after opponent contact.
THE DEVELOPMENT OF INJURY PREVENTION EDUCATIONAL TOOLS FOR EVALUATION IN CHILDREN AND ADOLESCENTS IN SCHOOL AND COMMUNITY SETTINGS
Authors: Djerboua Maya , Berg Carla van den , Richmond Sarah A. , McKinlay Megan , White Kyla , Hagel Brent , Emery Carolyn
Published: August 2017

Background

Educational resources are important tools in the implementation of sport injury prevention strategies to help foster uptake of information in a community setting; however, there is limited information on how these tools are developed.

Objective

To develop two injury prevention educational tools targeting children and adolescents for evaluation in school and community settings.

Design

Qualitative.

Setting

Schools and ski/snowboard facilities in Calgary, Canada.

Participants

Key informants, including: 1) Community stakeholders from school and ski/snowboard settings, 2) Students ages 9–14 years, and 3) Ski/snowboard instructors, safety patrols and physical education (PE) specialists.

Interventions

Semi-structured focus groups and surveys were conducted with key stakeholders to explore pre-understandings, relevant content, delivery methods, and format of the tools. Consultations with community partners, PE specialists and ski/snowboard instructors and patrols helped further inform content and format during the development process.

Main Outcome Measurements

Videos and posters were developed based on feedback and discussions with key informants. These tools were designed as educational resources for teacher and student evaluation in two injury prevention studies.

Results

Videos were the main tools developed for the school-based delivery; including content about a neuromuscular training program and ski/snowboard safety strategies targeting injury prevention in youth sport. Focus group participants and informants emphasized the importance of understanding the target audience and adapting content and delivery approaches that increase the likelihood of successful uptake of key messages. This included communicating information in a clear and concise manner and utilizing visual and auditory cues to accommodate multiple learning styles. A health behaviour framework (i.e., Health Action Process Approach) was used to inform tool development.

Conclusions

Engaging informants supported the development of sport injury prevention educational tools. These tools are being utilized in studies evaluating their effectiveness in increasing knowledge, changing behaviour and reducing the risk of sport-related injury in school and community settings.
SKI AND SNOWBOARD SCHOOL PROGRAMS: INCIDENCE OF GRADE-SPECIFIC INJURY
Authors: Djerboua Maya , Sran R , Mitra T , Russell K , White K , Goulet C , Emery CA , Hagel BE
Published: August 2017

Background

Participating in school sanctioned skiing and snowboarding programs is a great way to encourage physical activity in youth. However, there is little evidence on the rates of ski and snowboard injuries in school programs. This information is important to inform guidelines on appropriate activities for school physical education programs.

Objective

To evaluate incidence of grade group-specific ski and snowboard-related injuries.

Design

Historical cohort study.

Setting

Ski and snowboard school programs hosted at a ski area in Southern Alberta, Canada.

Participants

Students partaking in skiing/snowboarding during the 2013–2014 season at a ski area in Southern Alberta (N=16260 visits).

Assessment of Risk Factors

Risk factors observed include grade (1–3, 4–6, 7–12), ability (self-rated skill level), sex, activity and socioeconomic status (SES).

Main Outcome Measurements

Injury rates and injury severity. Injury information was extracted from Accident Report Forms completed by the ski patrol. Severe injuries were defined as patient final destination listed as hospital. Rate denominator data were obtained from school enrolment forms.

Results

Forty of 107 (24%) injuries reported to the ski patrol were severe. Adolescents (grade 7–12) were found to have a higher crude rate of injury (91/10,000 visits) than children (grades 1–3: 25/10,000 visits; grades 4–6: 25/10,000 visits). When adjusted for other observed risk factors (sex, activity, ability and SES) no significant differences were found for rate of injury between the three grade groups (1–3, 4–6 and 7–12). No severe injuries were observed in the grade 1–3 group.

Conclusions

Results indicate that participants in the grade 1–3 group had the lowest crude and adjusted rate of injury and did not sustain any severe injuries. Respectively, the grade 7–12 group had the highest rate of crude injury, both overall and severe. These results will help inform ski and snowboard programs and safety guidelines for physical activity programs in schools.
THE EFFECT OF REPETITIVE KICKING ON KNEE FLEXOR NEUROMUSCULAR FUNCTION
Authors: Duhig Steven , Williams Morgan , Minett Geoffrey , Opar David , Shield Anthony
Published: August 2017

Background

The primary mechanism for hamstring strain injury is high speed running however insults also occur during kicking in which they are more severe.

Objective

To examine the effect of 100 drop punt kicks on isokinetic knee flexor strength and surface electromyographic (sEMG) activity of biceps femoris (BF) and medial hamstrings (MH).

Design

Randomised control study.

Setting

Community level Australian football.

Participants

Thirty-six recreational footballers were recruited.

Interventions

Participants were randomly assigned to kicking or control groups. Dynamometry was conducted immediately before and after the kicking or 10 minutes of sitting (control).

Main Outcome Measurements

Knee flexor strength and biceps femoris and medial hamstring surface electromyography.

Results

Eccentric strength declined more in the kicking than the control group (p<0.001;d=1.60), with greater reductions in eccentric than concentric strength after kicking (p=0.001;d=0.92). No significant between group differences in concentric strength change were observed (p=0.089;d=0.60). The decline in normalized eccentric hamstring sEMG (BF and MH combined) was greater in the kicking than the control group (p<0.001;d=1.78), while changes in concentric hamstring sEMG did not differ between groups (p=0.863;d=0.04). Post-kicking reductions in sEMG were greater in eccentric than concentric actions for both BF (p=0.008;d=0.77) and MH (p<0.001;d=1.11). In contrast, the control group exhibited smaller reductions in eccentric than concentric hamstring sEMG for BF (p=0.026;d=0.64) and MH (p=0.032;d=0.53). Reductions in BF sEMG were correlated with eccentric strength decline (R=0.645; p=0.007).

Conclusions

Reductions in knee flexor strength and hamstring sEMG are largely limited to eccentric contractions and this should be considered when planning training loads in Australian Football.