Increased Humeral Retrotorsion is not a Risk Factor for Overuse Injury of the Throwing Shoulder in Elite Youth Handball Athletes.

PURPOSE: To identify the potential role of humeral retrotorsion (HRT) and range of motion (ROM) as a risk factor for shoulder overuse injury in elite youth handball players. The hypothesis was that increased HRT is associated with an increased risk of shoulder overuse injury. METHODS: Over two seasons, 258 elite youth handball players (52% boys; age:14±0.8years) were included. Pre-season assessment included HRT and glenohumeral internal (IR) and external (ER) rotational ROM using ultrasound and a manual goniometer. Sports-specific adaptations between male and female athletes and the dominant and nondominant shoulder were calculated. In addition, players completed standardized questionnaires over the 2018-2019 or 2019-20 season and reported any shoulder overuse symptoms using the Western Ontario Shoulder Index questionnaire. RESULTS: Comparing male and female players showed significantly decreased HRT and decreased internal ROM in the dominant side of male athletes (p≤0.027). No other difference was found. Significant side-to-side differences between the dominant and non-dominant shoulder were found for HRT, IR, and ER, regardless of sex (p<0.001). For total range of motion (TROM), only female athletes showed a significant increase in the dominant arm (p=0.032). The dominant side showed a significantly higher glenohumeral internal rotation deficit (GIRD) in male athletes than in female athletes (10°±17° vs. 5°±10°, p=0.011). Adaptations in HRT, ER gain, and TROM gain were not significant. Over the course of the two seasons, 20 athletes reported shoulder overuse injuries. Although GIRD was borderline non-significant (p=0.056), none of the parameters tested were significantly associated with shoulder overuse injuries. CONCLUSION: Despite significant side-to-side differences and sport-specific adaptations, individual pre-season screening of humeral retrotorsion and soft tissue adaptations does not identify elite youth handball athletes at increased risk of shoulder overuse injury.

Cardiorespiratory Markers Relate to Change-of-Direction Performance During Incremental Endurance Tests and Friendly Matches in Professional Male Handball Players.

PURPOSE: To compare the standard Yo-Yo intermittent recovery (IR) test and an agility Yo-Yo IR test with a higher number of change-of-direction movements to cardiorespiratory match performance. METHODS: The study included 11 professional male handball players (age 24.5 [4.6] y) of a German second-league team. The performance parameters of the players of the seasons 2016-17 to 2018-19 were analyzed. The Yo-Yo IR test was compared to a Yo-Yo IR test with multiple multidirectional changes of direction in response to visual stimuli, which was conducted on a SpeedCourt (Yo-Yo SC IR). Peak oxygen uptake (VO2peak) and maximum heart rate (HRmax) were measured. Between-methods differences of individual athletes were quantified with Bland-Altman plots. RESULTS: HRmax was not statistically different during the Yo-Yo SC IR test compared to the Yo-Yo IR test (181 [10] vs 188 [8] beats·min-1; P = .16). Agreement between the 2 tests was moderate for HRmax and good for heart rates >180 beats·min-1. Mean average VO2peak was 51.7 (3.9) and 50.9 (2.8) mL·min-1·kg-1 for the Yo-Yo SC IR test and the Yo-Yo IR test (P = .693), respectively. CONCLUSIONS: A Yo-Yo test with multidirectional changes of direction in response to visual stimuli yielded good agreement with the frequently used linear running tests and can be used to assess players' VO2peak. The HRmax achieved during this test should be used with caution.

Patient-specific articulating spacer for two-stage shoulder arthroplasty exchange.

OBJECTIVE: Two-stage exchange with an antibiotic-loaded polymethylmethacrylate (PMMA) spacer is standard treatment for chronic periprosthetic joint infection of the shoulder. We present a safe and simple technique for patient-specific spacer implants. INDICATION: (Chronic) periprosthetic joint infection of the shoulder. RELATIVE CONTRAINDICATIONS: Known allergy against components of PMMA bone cements. Inadequate compliance for two-stage exchange. Patient is unfit to undergo two-stage exchange. SURGICAL TECHNIQUE: Hardware removal, histologic and microbiologic samples, and debridement. Preparation of targeted or calculated antibiotic-loaded PMMA. Tailoring of patient-specific spacer. Spacer implantation. POSTOPERATIVE MANAGEMENT: Rehabilitation protocol. Antibiotic treatment. Reimplantation after successful eradication of infection.

Infraspinatus shift for massive, posterosuperior tears yields good clinical outcome.

AIM: To evaluate the functional outcome of partial reconstruction margin convergence in the treatment of massive, irreparable posterosuperior rotator cuff tear (RCT). METHODS: This retrospective, single-center study included all patients that were operated by means of a partial repair and infraspinatus shift for a massive, posterosuperior cuff tear between 2009 and 2016, either in arthroscopic or mini-open technique. Outcome measures included sex- and age-adapted Constant Score (saCS), Western Ontario Rotator Cuff (WORC) Index, Disabilities of Arm, Shoulder and Hand Scores (DASH), and relative effect per patient (REPP). RESULTS: Fifty-six shoulders in 54 patients (mean age: 66 ± 7 years) were evaluated at a mean follow-up of 40 ± 9 months. The mean tear size was Bateman 3.1 ± 0.7 and Patte 2.3 ± 0.4. All clinical scores showed improvement. The saCS improved from 64.1 ± 13.4 to 90.4 ± 13.7 (p < 0.0001), the DASH score from 51.8 ± 9.4 to 10.2 ± 13.4 (p < 0.0001) and the WORC index from 47.1% ± 8.6 to 87.9% ± 13.7 (p < 0.0001). The abduction strength of the affected side (1.7 ± 1.6 kg) was not restored to the same level as the contralateral side (5.4 ± 2.7 kg, p < 0.0001). CONCLUSION: Partial cuff repair for posterosuperior, massive cuff tears yields good clinical outcome with a low rate of complications and high proportion of good and excellent responders. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Reduced performance after return to competition in ACL injuries: an analysis on return to competition in the 'ACL registry in German Football'.

PURPOSE: ACL injuries are one of the most severe injuries in football, but medical consequences and performance outcomes after return to competition are only rarely investigated. Aim of this study was to analyse the time of return to competition (RTC) in German professional, semi-professional and amateur football. Also, this investigation highlights the rate of career ending and performance outcome after RTC in different playing levels by the measurement of playing level, performed matches and played minutes. METHODS: Database of this investigation is the 'ACL registry in German Football' with prospectively collected injury data. Between 2014 and 2018, four seasons in professional (1st-3rd league), semi-professional (4th-6th league) and amateur leagues (7th league) were analysed regarding the return to competition period and performance parameters. Data were collected for three subsequent seasons after injury and compared with the pre-injury and injury season. Data collection was performed using standardized methods. RESULTS: A total of 607 ACL injuries were registered during the 4-year period with a mean RTC time of 337.1 day (SD: 183). After primary ACL ruptures, the fastest RTC was found in professional football (247.3 days), while in semi-professional (333.5 d; p < 0.0001) and amateur football (376.2 d; p < 0.0001) a prolonged absence was detected. Re-ruptures occurred in 17.8% (n = 108) and showed similar trend with fastest RTC in professionals (289.9 days; p = 0.002). Within the first three seasons after injury, 92 players (36.7%) in semi-professional and 24 (20%) in professionals had to end their career. Keeping the level of play was only possible for 48 (47.5%) of professionals, while only 47 (29.6%) of semi-professionals and 43 (28.1%) of amateurs were able to. Only in professional football, no significant difference could be seen in the played minutes and games after 2 years compared to the pre-injury season. CONCLUSION: Lower playing levels and re-ruptures are the main factors for a prolonged return to competition after ACL rupture in German football. Significant reduction in playing level and a high rate of career endings were found for all levels of play. However, only professional players were able to regain their playing minutes and games 2 years after injury, while lower classed athletes did not reach the same amount within 3 years. LEVEL OF EVIDENCE: Level III.

Higher risk of ACL rupture in amateur football compared to professional football: 5-year results of the 'Anterior cruciate ligament-registry in German football'.

PURPOSE: Anterior cruciate ligament (ACL) injuries are a common severe type of football injury at all levels of play. A football-specific ACL registry providing both prospective ACL injury data according to the skill level and risk factors for ACL injury is lacking in the literature. METHODS: This study is based on the prospective 'ACL registry in German Football' implemented in the 2014-15 season. Professional (1st-3rd league), semi-professional (4th-6th league) and amateur leagues (7th league) were analysed regarding the incidence and risk factors for ACL injuries. Injuries were registered according to the direct reports of the injured players to the study office and double-checked via media analysis. After injury registration, the players received a standardised questionnaire. Data were analysed from the 2014-15 to the 2018-19 football season. RESULTS: Overall, 958 ACL injuries were registered during the 5-year study period. The incidence of ACL injuries was highest in amateur football (0.074/1000 h football exposure) compared to professional (0.058/1000 h; p < 0.0001) and semi-professional football (0.043/1000 h; p < 0.0001). At all skill levels, match incidence (professional: 0.343; semi-professional: 0.249; amateur: 0.319) was significantly higher than training incidence (professional: 0.015; semi-professional: 0.004; amateur: 0.005). Major risk factors were previous ACL injury (mean: 23.3%), other knee injuries (mean: 19.3%) and move to a higher league (mean: 24.2%). CONCLUSION: This sports-specific ACL registry provides detailed information on the incidence and risk factors for ACL injuries in football over five years. Risk factors are skill level, match exposure, move to a higher league and previous knee injury. These factors offer potential starting points for screening at-risk players and applying targeted prevention. LEVEL OF EVIDENCE: II.

Epidemiological analysis of injury occurrence and current prevention strategies on international amateur football level during the UEFA Regions Cup 2019.

INTRODUCTION: Football is the most popular sport worldwide and results in a high frequency of injuries. So far, mainly injuries in professional football have been investigated, and the literature lacks data regarding detailed injury epidemiology and current prevention data in amateur football tournaments. MATERIALS AND METHODS: A prospective cohort study investigated an international amateur football tournament, the UEFA Regions' Cup, which took place in 2019 in Germany. Injury epidemiology, current prevention strategies of the teams and the implementation of the UEFA concussion protocol were investigated in detail by means of standardized injury definitions and data samples for football (Fuller et al., Scand J Med Sci Sports 16:83-92, https://doi.org/10.1111/j.1600-0838.2006.00528.x , 2006). RESULTS: 138 player of 8 teams participated in this study, while 39 players were excluded. Overall injury incidence was 12.5 per 1000 h total football exposure, 43.5 per 1000 h for match exposure. No injuries were registered during training. Injury prevalence was 14.1% per player and 1.1 injuries per match were registered. The lower extremity was predominantly affected by injuries (71.4%) and the majority of injuries (78.6%) were non-severe injury types like contusions (50%) and sprains (18.2%). Two head injuries, one contusion and one skin lesion, were handled by the guidelines of the UEFA concussion protocol. 44.4% of the players indicated at least one previous injury before tournament, 45.3% of them during the last two football seasons before start of the tournament. Injury prevention performance was included in all participating teams during the tournament by warm up or training strategies (100%). During the warm-up program just 5 exercises of the FIFA 11 + program was detected by this investigation in participating teams to be done by more half of the teams. Running exercises were the most frequently performed exercises, while trunk muscle exercises were less represented (14.3%). CONCLUSION: This study presents for the first time epidemiological injury and prevention data of the UEFA Regions Cup. Injury incidence was higher compared to injury reports of regular seasons, but lower compared to other amateur football tournaments. Currently used prevention programs revealed trunk muscle exercises as often neglected.

Allo- and autografts show comparable outcomes in chronic acromioclavicular joint reconstruction: a systematic review.

PURPOSE: The aim of this review was to compare clinical and radiological outcome of acromio-clavicular joint reconstruction with allografts versus autografts. METHODS: The PubMed, MEDLINE, The Cochrane Library and WEB OF SCIENCE databases were searched in accordance with the PRISMA guidelines until February 2020 using the terms: 'coracoclavicular' OR 'coraco-clavicular' OR 'acromioclavicular' OR 'acromio-clavicular joint', AND 'reconstruction'. All studies reporting on clinical and radiological outcome as well as complications after ACJ reconstruction using allo- and/or autografts were included. RESULTS: A total of 29 articles, including 2 prospective and 27 retrospective studies, involving 622 patients, reconstructed with either allo- (n = 360) or auto-grafts (n = 262), for acromio-clavicular joint instability were identified and included in this review. The majority of studies had low sample sizes (66.7% below n = 20), were retrospective (93.3%), with short-term follow-ups (average 26.2 ± 12.6 months; range 6-186). The study with the largest sample size (n = 128) did not report clinical outcome. A comparison between allo- and auto-graft showed no significant differences regarding age, gender, and follow-up times. Clinical outcome was comparable in both groups, loss of reduction (LOR) and complication rates were higher in the allograft group. Overall a reduction of LOR was shown if additional horizontal stabilization was performed. Also a higher LOR and revision rate was documented in allografts without suture or suture-tape augmentation. The use of more clavicular drill-holes correlated with a higher frequency of fracture. CONCLUSIONS: A systematic review of the available peer-reviewed literature addressing allograft and autograft reconstruction of unstable coracoclavicular ligaments shows that the published studies are generally of low quality with low levels of evidence. The published literature shows no significant difference in clinical outcomes between the use of autografts or allografts in ACJ reconstruction surgery. Surgical techniques utilizing additional horizontal stabilization may contribute to lower rates of LOR. In cases where allograft tissue is used for ACJ reconstruction the use of suture/tape augmentation may reduce LOR rates as well as revision rates. LEVEL OF EVIDENCE: III.

Injury epidemiology in men's professional team sports: is media analysis helpful?

INTRODUCTION: Epidemiological injury surveillance in professional sports is often based on online media analysis in order to collect necessary data. However, the validation of this study protocol is lacking. Therefore, this study aimed to identify the validity of injury surveillance in men's professional team sports based on media reports. METHODS: In a retrospective cohort study, the validity of media-data-relating injuries was investigated in participating teams of the highest two German divisions in men's professional basketball (BB) and handball (HB) in the season 2018/2019. Injury protocols completed by the team physicians were compared to those of sports media injury reports. RESULTS: The study population was composed of 133 athletes (54 BB and 79 HB). Of 343 injuries reported by the team physicians, 151 (44%) could be identified by means of sports media reports. Severe injuries (n = 75, 72%) were reported more likely in sports media compared to less severe injuries (n = 76, 32%, p < 0.00001). Odds ratio (OR) was 5.33 (95% CI 3.22-8.82). No differences regarding injury reporting could be seen between the two team sports. CONCLUSION: For severe injuries, media analysis may be a sufficient method for data collection in popular men's professional ball sports. An underestimation of true injury prevalence lies within the range of previous reported investigations concerning the validation of injury surveillance methods. Non-severe injuries could not be verified via media analysis in professional handball and basketball.

Increased posterior shoulder capsule thickness in youth elite handball players: a sonographic investigation.

PURPOSE: Range of motion adaptations in the shoulders of overhead throwing athletes have been reported, but knowledge about the development of soft-tissue adaptations is limited. The purpose of this study was to investigate differences in posterior shoulder capsule thickness and internal rotation between the throwing and non-throwing shoulder. METHODS: On the basis of the sample size calculation, we assessed 63 youth elite handball players (33 boys and 30 girls, mean age: 13.6 ± 0.9 years) for glenohumeral internal and external rotational range of motion, humeral retrotorsion, and posterior capsule thickness (PCT) with a manual goniometer and a portable ultrasound device and calculated sports-specific differences between the throwing and non-throwing shoulder as well as correlations with PCT. RESULTS: Youth handball players showed side-to-side differences in internal rotation, external rotation, and humeral retrotorsion between the throwing and non-throwing shoulder. Posterior shoulder capsules were 1.21 times thicker (95% confidence interval: 1.1-1.3) in the throwing shoulder than in the non-throwing shoulder (1.3 ± 0.3 mm vs. 1.2 ± 0.2 mm, P < .0001). Loss of internal rotation did not correlate with PCT. CONCLUSIONS: In youth elite handball athletes, posterior shoulder tightness and subsequent sports-specific loss of internal rotation in the throwing shoulder are not related to PCT. Thus, in this age class, other (soft-tissue) factors must be responsible for this condition.

Decreased external rotation strength is a risk factor for overuse shoulder injury in youth elite handball athletes.

PURPOSE: Overuse shoulder injuries are common in youth handball, but research is limited. The purpose of this study was to identify pre-season risk factors associated with overuse shoulder injuries in this population. METHODS: One-hundred and thirty-eight (70 boys and 68 girls) youth elite players (age 14.1 ± 0.8 years, height 175.2 ± 8.2 cm, weight 64.0 ± 9.6 kg) completed a pre-season screening protocol. Passive glenohumeral range of motion and maximum external (ER) and internal rotation (IR) strength were measured with a manual goniometer and a hand-held dynamometer. Scapular dyskinesia and maximum throwing velocity were also assessed. Players completed standardised questionnaires over the 2017-2018 season and reported any overuse shoulder symptoms. RESULTS: Decreased isometric and eccentric ER strength was identified as a risk factor for overuse shoulder injury, both for absolute (OR 10.70, 95% CI 1.2-95.6, p = 0.034) and normalised ER strength (OR 1.2, 95% CI 1.0-1.4, p = 0.015) and the ER:IR strength ratio (OR 1.2, 95% CI 1.1-1.5, p = 0.012). ER gain of more than 7.5° (p = 0.025) and GIRD of more than 7.5° (p = 0.014) were identified as risk factors for overuse shoulder injury in girls. Scapular dyskinesia (OR 1.1, n.s.) and maximum throwing velocity did not seem to contribute to injury risk. The average response rate was 63%. CONCLUSION: In elite youth handball, deficits in ER strength is a risk factor for overuse shoulder injury for both sexes; ER gain and GIRD are only risk factors for girls. Focused pre-season assessments may aid the identification of risk factors for shoulder overuse injuries and the application of specific programmes to reduce risk. LEVEL OF EVIDENCE: II.

Prevention of severe knee injuries in men's elite football by implementing specific training modules.

PURPOSE: Injury prevention of knee injuries by means of training and warm-up exercises has been investigated in several studies in amateur football. However, the number of investigations in elite football is limited despite the currently higher injury incidence of severe knee injuries. Therefore, the purpose of this study was to investigate whether specifically adapted preventive training modules may reduce severe knee injuries in elite football. METHODS: In a prospective controlled cohort study of elite football players in Germany, an injury prevention programme with 5 modules was implemented in the season of 2015-2016. The training modules were specifically adapted to this skill level and based on scientific evidence, team coach preferences, and the specific environment of this playing level. Of the 62 teams taking part in this study, 26 used the new trainings modules and 36 continued their standard programme as a control group. Success of the programme was documented by means of an injury report over one season. The primary outcome was reduction in severe knee injuries. RESULTS: A pre-seasonal investigation had identified five modules to be implemented in the training routine. Postural stability, mobilisation of lower extremity joints, leg and trunk stabilisation, jumping, and landing exercises as well as agility movements were incorporated into the programme to prevent severe knee injuries in elite football. Over the season, the study group (529 players) with the adapted training modules had sustained 52 severe knee injuries (incidence: 0.38 per 1000 h football exposure; prevalence: 9.8%) compared to 108 severe knee injuries in the control group (601 players) using the standard programme (incidence: 0.68 per 1000 h football exposure; prevalence: 18.0%; p < 0.05). The overall injury incidence for any other type of injury was comparable between the two groups (3.3 vs. 3.4 in h 1000 football, n.s.). CONCLUSION: Appropriate preventive training modules reduce severe knee injuries in elite football significantly. The key for the sustainability of preventive training measures are programmes specifically adapted to the demands of the playing level and to the preferences of the coaches LEVEL OF EVIDENCE: II.

Influence of poor preparation and sleep deficit on injury incidence in amateur small field football of both gender.

INTRODUCTION: Amateur small-field football tournaments are rather common worldwide. Adequate preparation is essential for injury prevention. The consequences of insufficient injury preparation at this level are still unclear. This study investigates the factors influencing injuries in this football population. MATERIALS AND METHODS: In 2017, medical students participating in a national amateur football tournament were analysed in a prospective cohort study. Injury incidence, injury pattern and factors influencing injuries were investigated according to the statement on data collection and injury definition of Fuller et al. (Br J Sports Med 40:193-201, 2006). Preparation for the tournament was assessed for both sexes by means of hours of sleep, alcohol consumption, training level and warm-up performance. LEVEL OF EVIDENCE: II. RESULTS: Of 694 amateur football players (423 men and 271 women) with a mean age of 23 years (SD 2.5), 321 (21.1%) injuries happened during the tournament. 60% of injuries affected the lower extremity. The most common types of traumatic injury were skin abrasions (40.0%) and muscle strains (23.3%). The injury incidence of male players during match exposure was 469 per 1000 h football and significantly higher than in female players 313 (p = 0.025). One potential reason for the higher injury rate of male players as measure for inadequate preparation was significantly higher alcohol consumption the evening before the tournament (p < 0.001) and the after-effects on match day (p < 0.001). Additionally, male players reported less and inadequate sleep the night before the tournament (p < 0.007) and a lower warm-up rate before the matches compared to female players (p < 0.001). CONCLUSIONS: Small-field tournaments in football have a high injury incidence. Male players have a higher injury incidence than female players and show additionally a lack of sleep and alcohol consumption the night before the tournament and poor warm-up performance on match day. Adequate preparation for a football tournament is the key factor for preventing injuries, also in recreational football.

The throwing shoulder in youth elite handball: soft-tissue adaptations but not humeral retrotorsion differ between the two sexes.

PURPOSE: In youth handball players, knowledge about the development of soft-tissue adaptation and humeral retrotorsion is limited. The purpose of this study was to investigate differences in adaptations in the glenohumeral rotational range of motion and humeral retrotorsion of the throwing arm between male and female youth elite handball players. METHODS: One-hundred and thirty-eight youth elite handball players (mean age: 14.1 ± 0.7 years) were assessed for glenohumeral external (ER) and internal (IR) rotational ranges of motion and humeral retrotorsion (HRT) by means of a manual goniometer and a portable ultrasound device. Sports-specific adaptations between the dominant and non-dominant shoulders and between male and female adolescents were calculated. RESULTS: Handball players showed side-to-side differences in IR and ER in the throwing shoulder. HRT did not correlate with the measurements of rotational ROM of the throwing arm. Male athletes showed a more pronounced glenohumeral internal rotation deficit than female athletes (13.1° ± 22.8° vs. 5.1° ± 14.0°, p = 0.014). Adaptations in HRT but no sex differences could be seen in the throwing shoulder (16.5° ± 9.6°) compared to the non-throwing shoulder (13.5° ± 9.4°, p < 0.001). CONCLUSION: Loss of internal rotation and gain in external rotation in youth handball players seem to be more related to adaptive changes in the soft-tissues than to HRT. Male athletes showed stronger throwing-related adaptations in the rotational range of motion but not in humeral torsion in their dominant shoulder than female athletes. LEVEL OF EVIDENCE: Cross-sectional study, Level II.

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.

Contact times of change-of-direction manoeuvres are influenced by age and the type of sports: a novel protocol using the SpeedCourt® system.

PURPOSE: Side-to-side asymmetry in side-cutting manoeuvres is a known risk factor for severe knee injury. Potential leg asymmetry during ground contact times of different change-of-direction manoeuvres was evaluated in athletes by means of the recently developed SpeedCourt® system. The hypotheses were that ground contact times and the limb symmetry index are affected by age and the type of sports. METHODS: One-hundred and sixty-five athletes (149 men, 16 women, age 16.5 ± 5.1) of popular team sports such as football, team handball and baseball were assessed by means of three different tests [side-hop, lateral change-of-direction (COD) and diagonal COD] using the SpeedCourt® system. Analysis included the factors age, sex, type of sports, ground contact time, leg symmetry index and limb dominance. RESULTS: During lateral but not diagonal COD tests, football players had shorter contact times than players of team handball (p = 0.026) and baseball (p = 0.015) of the same age group. The side-hop tests yielded differences in the leg symmetry index between players < 16 years and players > 16 years (p < 0.01). Mean ground contact time differed in each of the side-hop, lateral COD and diagonal COD tests (143.5 ± 20.0 vs. 256.2 ± 66.1 vs. 320.4 ± 55.0). Contact times and test durations of side-hop, lateral COD and diagonal COD tests were shorter for older players (p < 0.01). CONCLUSIONS: Ground contact times of side-hop and change-of-direction manoeuvres are influenced by age, the type of sports and limb dominance. Such information is fundamental for future sports medicine research and needs to be considered in pre-season screening or when used as a criterion for return-to-competition of players with previous severe knee injury. Assessment of change-of-direction manoeuvres should be included in future return-to-competition test batteries. LEVEL OF EVIDENCE: III.

Injury prevention and return to play strategies in elite football: no consent between players and team coaches.

INTRODUCTION: Injuries are a common problem in football. To improve prevention strategies, the players' (p) and coaches' (c) views need to be disclosed as they have a strong impact on return to play decisions. The aim of this study is to reveal current opinions with regard to injury prevention and return to play strategies to introduce new strategies in elite football. MATERIALS AND METHODS: In a retrospective data analysis of elite salaried football players (n = 486) and team coaches (n = 88), a detailed investigation by means of a standardized questionnaire was carried out. In a preseason period of the 2015/16 season and as part of a large interventional research project in elite salaried German football, a request about players' and team coaches' knowledge and opinions was performed. Topics such as injury prevention, return to play after injuries, the importance of screening tests, general problems of injuries in football, or the decision-making in terms of prevention and return to play in elite football were investigated. RESULTS: The study revealed a high interest in injury prevention and screening tests among players and coaches (p 82.5%; c 99.1%). The participants of the study reported warm-up exercises (p 76.4%; c 74.7%), regeneration training (p 54.1%; c 56.3%), and core stability (p 53.8; c 70.1%) as the most important prevention methods, but the additional investigation of the teams' current daily training routine showed that the transfer is incomplete. Coaches are more familiar with scientific published warm-up programs like FIFA 11 + than players (42.5 vs. 12.6; p < 0.001). Knee injuries (p 90.7%; c 93.1%) and ACL injuries in particular were reported as the most severe and common problem in elite football. Players and coaches expressed different attitudes concerning return to play decisions. While players want to decide themselves (81.4%), team coaches consult medical advice ahead of the decision of return to play after injuries (83.5%; p < 0.001). Decisions against the doctor's recommendation are often made by both groups (p 64.4% vs. c 87.1%; p < 0.001). CONCLUSION: The basic knowledge of prevention and injuries is sufficient in elite football, but the transfer from theoretical knowledge to practical routine is suboptimal. The study also shows possibilities to improve the prevention process and communication between players, coaches, doctors, and physiotherapists, while there is no consent between players and coaches regarding return to play decision.

Beach handball is safer than indoor team handball: injury rates during the 2017 European Beach Handball Championships.

PURPOSE: Beach handball is a relatively new type of sports, which was derived from team handball. Medical issues such as frequency and severity of injury are yet unknown. The purpose of this study was to investigate the injury pattern and injury rates of this new type of sports. METHODS: This study investigated the injury incidence of 30 national teams (10 senior and 20 u-17 teams, 16 men's and 14 women's teams) participating in the 2017 European Beach Handball Championships. Reports on injuries sustained during the senior and u-17 youth tournaments were provided by the medical staff of each team. Injury incidence was differentiated between age and sex, and between the five field positions (goalkeeper, wing, central defender, pivot, and specialist). RESULTS: During the tournaments, 87 injuries were recorded yielding an overall injury incidence of 286.1 per 1000 match hours. Time-loss due to injury was 49.3 per 1000 match hours. Senior players had a higher overall injury incidence with 395.3 injuries than u-17 players with 205.7 injuries per 1000 h match hours (p < 0.01). Comparison of the injury incidence between the two sexes showed 330.23 injuries per 1000 h handball exposure for male players and 234.9 injuries for female players (n.s.). The most frequent injury type was sprains (21 injuries, 24.1%) followed by contusions (19 injuries, 21.8%) and skin abrasions with (15 injuries, 17.2%). Central defenders and specialists had the highest injury incidence. Thighs, ankles, as well as foot and toes (altogether 12 injuries, all 13.8%) were the three most frequently injured anatomic sites. CONCLUSIONS: Beach handball seems to have a lower incidence of time-loss injuries than that reported for indoor team handball. This study is an important basis for developing injury prevention strategies in this sports that should focus on thighs, ankles, feet and toes. Further research into this new type of sports is essential to identify risk factors and to develop adequate injury prevention measures. LEVEL OF EVIDENCE: II.

Correction to: Intra-ligamentary autologous conditioned plasma and healing response to treat partial ACL ruptures.

With regards to Berardo Di Matteo, second author. The author's name is incorrectly listed on Pub-Med. The first and last name have been mixed up.

Increased injury rates after the restructure of Germany's national second league of team handball.

PURPOSE: Scientific injury data in men's professional team handball injuries are rare and even less scientific information exists on injury prevention. In 2011, Germany's national second team handball league was restructured by merging the existing two regional leagues into one league. This study evaluates the injury patterns in professional team handball and compares the injury rates between the first and second league before and after the restructure. METHODS: All players of Germany's national first and second men's team handball leagues have mandatory trauma insurance with the same insurance company. This retrospective cohort study analysed the injury data of three consecutive seasons 2010-2013 using standardized injury definitions. RESULTS: 1194 professional team handball players were included in this study. The majority of severe injuries affected the lower extremities, shoulders, and hands. The average injury incidence significantly differed between the first (4.9 injuries per 1000 h) and the second league (3.9 per 1000 h, p < 0.01). The injury incidence in the restructured second league had increased from 3.7 to 4.1 per 1000 h (p < 0.01) and prevalence from 67.1 to 79.3% (p < 0.001), thus almost to the same levels of the first league. The second league showed more time-loss injuries at all severity levels. CONCLUSION: This study yielded a high injury incidence after the restructure of the national second team handball league and presents details on prevalence, incidence, and patterns of injury in professional men's team handball. This study is an important basis for developing injury prevention strategies that should focus on the shoulders, hands, and lower extremities and on reducing the number of matches and travel burden. LEVEL OF EVIDENCE: III.