'We may need some help; we are just parents who have chosen to engage in football': a qualitative study on amateur coaches' experiences of use of and support for injury prevention training in Sweden.

INTRODUCTION: Achieving sufficient adherence with injury prevention exercise programmes is a challenge. The aim was to explore how amateur football coaches experience the use of and support for injury prevention training using the Knee Control programmes as examples. METHODS: Semistructured interviews with 20 amateur football coaches around experiences of injury prevention training, facilitators and barriers, and perceived support, analysed with qualitative content analysis. Participants coached male and female, junior and senior teams. Experience of having used the Knee Control programmes was an inclusion criteria. RESULTS: Four main categories were developed: Why are we really doing this?, How do we make it work?, What are our drivers and challenges? and What could be improved? Coaches were motivated for injury prevention training but faced challenges such as limited access to football grounds and low player motivation. To make the prevention programme work for them, they integrated it and used exercises in the pauses during football-specific drills, or used as a warm-up. Many conducted prevention routines from an early player age. Coaches believed preventive training use could be further enhanced by education and practical support, and by football associations and clubs working together to reduce injuries. CONCLUSION: Coaches were motivated and creatively worked with the prevention programme to make it fit their team. Even coaches with long-term experience of using prevention programmes wanted support, indicating that present implementation strategies targeting those about to start using prevention programmes should be complemented by continuous support for maintained use. These strategies should preferably target both coaches and players.

To play or not to play, that is the question: an interview study with amateur football coaches on perceptions of pain during sports participation.

Amateur football coaches play a key role in preventing, assessing and treating pain among their players, as they are often the first point of contact and may be the main source of advice and guidance. The objective of this study was to explore amateur football coaches' perceptions of pain during sports participation and their approach to pain management. We conducted a qualitative interview study with 20 amateur football coaches from a strategically selected sample of male and female, and junior and senior teams. A semistructured interview guide and conventional qualitative content analysis were used. One overall theme emerged: To play or not to play-coaches navigating difficult terrain with limited resources. The theme included four main categories: How can pain be understood?; Can pain be avoided?; How to manage players with pain?; What resources do we need? Different ways of understanding pain emerged, and coaches described that players have different pain thresholds. Pain was seen as a part of the game that cannot be completely avoided. In general, there was a restrictive attitude regarding pain medication, though actual consumption was not known. Coaches emphasised shared responsibility with players to achieve adequate training loads, a positive communication climate surrounding pain, and a need for education and competence. In conclusion, coaches expressed various interpretations of pain during sports participation and pain management, where they need to take on great responsibility despite limited medical competence. Coaches believed that adequate pain management is important, and their keys to reducing the risk of pain included structured and customised training, a well-balanced training load and recovery, and a positive communication climate in the team. Coaches often decide whether players experiencing pain can participate in team training and match play, emphasising the need for education support and access to medical competence.

Players are positive regarding injury prevention exercise programmes, but coaches need ongoing support: a survey-based evaluation using the Health Action Process Approach model across one season in amateur and youth football.

Objectives: Implementation of injury prevention exercise programmes (IPEPs) in sports is challenging, and behaviour change among players and coaches is essential for success. The aim was to describe players' and coaches' motivation and coaches' goal pursuit when using IPEPs in amateur and youth football across a season. A secondary aim was to describe players' motivation to engage in IPEP use in relation to presence or absence of injury. Methods: The study was based on questionnaires to amateur and youth, male and female football players and coaches at baseline, mid-season and post-season in a three-armed randomised trial in 2020 in Sweden. Questionnaires were based on the Health Action Process Approach (HAPA) model with questions about the motivational phase when intention for change is created (players and coaches) and a goal-pursuit phase when intention is translated into action (coaches). Results: In total, 455 players (126 male), mean age 20.1 years (SD±5.8, range 14-46) and 59 (52 male) coaches took part. Players generally gave positive answers in the HAPA motivational phase (Likert 6-7 on a 1-7 Likert scale). Differences in ratings between injured and uninjured players were minor. Coaches had positive or neutral ratings (Likert 4-6) in the motivational and goal-pursuit phases. Ratings deteriorated across the season, with less positive responses from 40% of players and 38-46% of coaches post-season. Conclusion: Positive ratings in the HAPA motivational phase indicated fertile ground for IPEP use. Neutral ratings by coaches and deterioration across the season in players and coaches suggest a need for ongoing support for IPEP use. Trial registration number: NCT04272047.

Prevalence and intensity of pain in male and female amateur football players: A prospective cohort study.

OBJECTIVES: To determine the prevalence and intensity of pain due to a football-related injury during activities of daily living and during training and/or match play in both male and female and youth and adult amateur players. DESIGN: A prospective cohort study involving amateur football players. METHODS: Players (n = 502, median age 18 years, range 14-46) responded to weekly questionnaires during one season, including the Oslo Sports Trauma Research Center Overuse Injury Questionnaire. Weekly pain prevalence and pain intensity (measured on the numeric rating scale [range 0-10]) during activities of daily living and while playing football were determined. RESULTS: A total of 6601 weekly questionnaires were collected (response rate 63.7 %). Average weekly pain prevalence during activities of daily living was 17.2 % for all players, and 15.7 % among players who participated in training and/or match play. Pain prevalence during training and/or match play was 18.3 % with an average pain intensity of 4.0. In 21.3 % of cases the recorded pain intensity was >5. Sex, age, and mode of injury onset (sudden or gradual) were not significant predictors of pain intensity. CONCLUSION: At a given week, one in six football players experiences pain during activities of daily living from a football-related injury. Almost one in five players reports pain while playing football, of whom >20% report a pain intensity above 5. Oftentimes, injury-related pain present while playing football transcends to activities of daily living. This warrants further monitoring and adequate management of pain within amateur football.

Motivation and goal-pursuit for injury prevention training in amateur football coaches: a cross-sectional study using the Health Action Process Approach.

BACKGROUND: Adoption of injury prevention exercise programmes (IPEPs) in team sports is contingent on behaviour change among coaches. The aim was to study motivation and goal-pursuit in IPEP use among coaches of amateur football players. METHODS: A cross-sectional study using web-based questionnaires was administered to coaches in one Swedish regional football district. The study was carried out one season after dissemination of the IPEP Knee Control+. The questionnaire was based on the Health Action Process Approach and covered perceptions and beliefs about using Knee Control+. Questions were rated on 1-7 Likert scales. RESULTS: 440 coaches participated (response rate 32%). Coaches were neutral about injury risks (median 4-5) and knowledge about preventing injuries (median 5) but had positive outcome expectancies of preventive training (median 6). Coaches who had used an IPEP perceived they had more knowledge about preventing injuries than non-users (median 5 vs 4, small effect size d=0.43). Coaches who used Knee Control+ were positive about their practical ability to use it (median 6) and had high intention to prioritise continuous use (median 7). Highly adherent coaches to higher extent believed that specific training may prevent injuries and had plans for how to instruct the players and how to work around barriers compared with low adherent coaches. CONCLUSION: Coaches need more knowledge and support on IPEP usage and how to structure training. Coaches who had adopted Knee Control+ had high belief in their abilities but may need constructive plans on how to use the programme and to overcome barriers.

Higher age and present injury at the start of the season are risk factors for in-season injury in amateur male and female football players-a prospective cohort study.

PURPOSE: To describe the injury prevalence, injury pattern, and potential baseline risk factors for injuries in male and female adolescent and adult amateur football players. METHODS: This prospective study followed adolescent and adult amateur football players over one season March-October 2020. The study was completed by 462 players (130 men, age 20.0 ± 5.7, 14-46 years) who answered a baseline survey and a weekly web survey during the season. A total of 1456 weekly surveys were registered from males and 5041 from females. Injuries were recorded with the Oslo Sports Trauma Research Center Overuse Injury Questionnaire (OSTRC-O2). Potential baseline risk factors (age, performance of strength/conditioning training, participation in other sports, perceived importance of sporting success, self-rated training and match load, perceived balance between training/match load and recovery, previous/present injury at start of season, and injury beliefs) and their association with injury were analysed with Poisson regressions within each sex. RESULTS: Males reported 95 injuries (262 injury weeks, weekly prevalence 18.0% (95% CI 16.1-20.1)) and females 350 injuries (1206 injury weeks, weekly prevalence 23.9% (95% CI 22.8-25.1)). Gradual-onset injuries accounted for 57% of the injuries in males and 66% in females. For males, substantial injuries were most common in the hip/groin (weekly prevalence 3.8%), ankle (2.1%), posterior thigh (2.0%), and knee (2.0%); and for females, in the knee (4.3%), ankle (2.5%), and lower leg/Achilles tendon (2.0%). Significant risk factors for injury were higher age (rate ratio males 1.05 per year increase (95% CI 1.02-1.08), females 1.03 (95% CI 1.01-1.05)), and present injury at baseline (males 1.92 (95% CI 1.27-2.89), females 1.58 (95% CI 1.19-2.09)). CONCLUSION: At any given week, almost one in five male and one in four female amateur football players reported new or ongoing injuries. Hip/groin injuries were more frequent in males, while female players had a higher prevalence of knee injuries. Older players and those with an existing injury at the start of the season were more prone to new injury during the season. Rehabilitation of pre-season injury and complaints are key to reduce the injury burden in amateur football. LEVEL OF EVIDENCE: Level II. Trial registration number NCT04272047, Clinical trials.

Swedish Olympic athletes report one injury insurance claim every second year: a 22-year insurance registry-based cohort study.

PURPOSE: To describe injury incidence, time trends in injury incidence, and injury characteristics among Swedish Olympic athletes over 22 years based on insurance data, as a first step to inform injury preventive measures among Olympic athletes. METHODS: The cohort comprised 762 elite athletes (54% males; age 26.5 ± 5.9 years) in 38 sports in the Swedish Olympic Committee support program 'Top and Talent' between 1999 and 2020, with total 3427 athlete-years included. Acute and gradual onset injuries were reported to the insurance registry by the athletes' medical staff. RESULTS: A total of 1635 injuries in 468 athletes were registered. The overall injury incidence was 47.7 injuries/100 athlete-years (one injury per athlete every second year). An increasing trend in injury incidence was observed in the first decade 2001 to 2010 (annual change 6.0%, 95% CI 3.3-8.8%), while in the second decade 2011 to 2020 no change was evident (0.4%, 95% CI - 1.9 to 2.7%). Gymnastics, tennis, and athletics had the highest incidence (100.0, 99.3, and 93.4 injuries/100 athlete-years, respectively). Among sport categories, mixed and power sports had the highest incidence (72.8 and 69.5 injuries/100 athlete-years, respectively). Higher incidences were seen in the younger age groups (≤ 25 years) in mixed and skill sports. The injury incidence was comparable between male and female athletes, and summer and winter sports. Most injuries occurred in the lower limb, and specifically the knee (24%), foot/ankle (15%) and spine/pelvis (13%). CONCLUSION: The results on injury patterns in different sports and age groups may guide preventive focus for health and performance teams working with Olympic athletes. LEVEL OF EVIDENCE: II.

Adherence to Injury Prevention Exercise Programmes in Amateur Adolescent and Adult Football: A Detailed Description of Programme Use from a Randomised Study.

BACKGROUND: Injury prevention exercise programmes (IPEPs) efficaciously reduce injuries. However, it is challenging to achieve sufficient adherence across a season. The main aim was to describe adherence to IPEPs in three groups of coaches and players partaking in a cluster randomised trial. Secondary aims were to describe perceptions of IPEPs, use of programme material, and overall preventive strategies. METHODS: This is a sub-study analysing data from a three-armed randomised trial with teams randomised to use either a comprehensive IPEP (extended Knee Control) or an adductor strength programme, and non-randomised teams that already used a self-chosen IPEP regularly at study start (comparison group). Teams were instructed to use their respective intervention across the 2020 football season. Male and female, adolescent (≥ 14 years of age), and adult amateur players took part. Coaches and players responded to weekly and end-of-season questionnaires. Data were presented descriptively. RESULTS: Weekly player data were reported by 502 players (weekly response rate 65%), 289 (58%) responded to end-of-season questionnaires. Teams in the extended Knee Control and comparison group used their respective IPEP in 483/529 (91%) and 585/641 (91%) of training sessions, and teams in the adductor group in in 199/315 (63%) sessions. Regarding utilisation fidelity, 42-52% of players in each group used 1-10 repetitions per exercise. Seven out of 17 teams in the adductor group had progressed as recommended in terms of number of repetitions. Two teams (10%) in the extended Knee Control group, and 7/24 of comparison teams used the same exercises across the season. Coaches accessed the IPEPs by different means (printed material, films, workshops, etc.), but half did not use the provided digital material. The players appreciated that the IPEPs could reduce injury risk and that they improved their exercise performance, but disliked that they had less time for football and that the exercises were boring. Forty-nine players had experienced pain during IPEP performance. CONCLUSIONS: Adherence with the IPEPs was generally high. To meet different coach needs, programme material should be available via different digital and printed resources. The number of players reporting pain during IPEP performance is a noteworthy finding. TRIAL REGISTRATION: Clinical Trials gov identifier: NCT04272047. Registered February 17, 2020. https://clinicaltrials.gov/ct2/show/NCT04272047 .

The side hop test: Validity, reliability, and quality aspects in relation to sex, age and anterior cruciate ligament reconstruction, in soccer players.

OBJECTIVE: To study the side hop test regarding validity, reliability, and quality in relation to sex, age and ACL-reconstruction in soccer players. DESIGN: Cohort study. PARTICIPANTS: 117 females with a primary ACL-reconstruction, and 119 females, 46 males (age 16-26 years), 49 girls and 66 boys (age 13-16 years) without injury. MAIN OUTCOME MEASURES: For convergent validity, one physiotherapist analysed side hops live and later on video. One physiotherapist and two physiotherapy students analysed side hops from 92 players for interrater reliability (video). For intrarater reliability, side hops from 35 players were analysed twice (video). Quality aspects (flaws), i.e. number of times the hopping limb touched the strips, the non-hopping limb touched the floor, and double hops/foot turns with the hopping limb, were registered (video). RESULTS: Convergent validity was excellent; the intraclass correlation coefficient (ICC) was 0.93-1.0. All reliability measures were excellent (ICC 0.92-1.0). Adult male players had fewest and girls had most flaws, especially double hops/foot turns with the hopping limb, compared with all other players (mean, 11-12 vs 1-6, η2 = 0.18, large effect size). No differences were reported between knee-healthy and ACL-reconstructed females. CONCLUSION: The side hop test is valid and reliable. Quality aspects differ between sexes and ages.

Implementation of the injury prevention exercise programme Knee Control+: a cross-sectional study after dissemination efforts within a football district.

BACKGROUND: The Reach, Effectiveness, Adoption, Implementation, and Maintenance (RE-AIM) framework can be used for evaluation of implementation initiatives in sports injury prevention. The aim was to evaluate the implementation of the injury prevention exercise programme Knee Control+ among amateur clubs and coaches in one regional football district using all five dimensions of the RE-AIM framework. METHODS: Dissemination of Knee Control+ during the 2021 season with information and webinars within one regional football district. This was followed by a cross-sectional study with questionnaires to club personnel and coaches after the season. RESULTS: The reach of Knee Control+ was fair to high, 83% of club personnel and 66% of coaches knew about the programme. 41% of club personnel and 51% of coaches had adopted it. Perceived programme effectiveness was high (6 on a 1-7 Likert scale) among coaches. Regarding implementation and maintenance, 27% of club personnel had informed coaches about Knee Control+ and 57% planned to inform coaches. The coaches had implemented the programme mainly as recommended, but half used the programme once per week or less. Intention to maintain use of the programme was high (7 on a 1-7 Likert scale) among coaches. CONCLUSION: The reach of Knee Control+ was fair to high, and adoption was fair in clubs, but there was a lack of policies for preventive training. Active strategies probably need to accompany dissemination of programme material. Reach, perceived effectiveness, adoption, implementation and planned maintenance were positive among coaches, but further studies are needed to analyse long-term maintenance.

Perceptions, facilitators, and barriers regarding use of the injury prevention exercise programme Knee Control among players and coaches in youth floorball: a cross-sectional survey study.

BACKGROUND: Youth participation in team ball sports is associated with a risk of both acute and gradual onset injuries but today there are several efficacious injury prevention exercise programmes (IPEPs). However, there is limited research about how to implement those programmes and the perceived barriers and facilitators among end-users. OBJECTIVE: To investigate perceptions of the IPEP Knee Control and facilitators and barriers to programme use among coaches and youth floorball players, and explore factors associated with planned maintenance of Knee Control. METHODS: This cross-sectional study is a sub-analysis of data from the intervention group of a cluster randomised controlled trial. Perceptions about Knee Control and facilitators and barriers to programme use were evaluated with surveys pre-intervention and post-season. 246 youth floorball players aged 12-17 years, and 35 coaches that reported no use of IPEPs during the preceding year were included. Descriptive statistics and univariate and multivariate ordinal logistic regression models were undertaken with the dependent variables: coaches' planned maintenance and players' opinions of maintenance of Knee Control. Independent variables were perceptions, facilitators and barriers regarding use of Knee Control and other potential influencing factors. RESULTS: 88% of the players believed that Knee Control can reduce injury risk. Common facilitators to Knee Control use among coaches were support, education and high player motivation, and common barriers were that injury prevention training was time-consuming, lack of space to execute the exercises and lack of player motivation. Players who planned to maintain use of Knee Control had higher outcome expectancies and belief in one's ability to use Knee Control (action self-efficacy). Coaches who planned to maintain Knee Control had higher action self-efficacy and to a lesser extent considered that Knee Control takes too much time. CONCLUSIONS: Support, education, and high player motivation are key facilitators, while lack of time and space for injury prevention training and boring exercises are key barriers for coaches and players to use Knee Control. High action self-efficacy among coaches and players seems to be a prerequisite for maintained use of IPEPs.

Extended Knee Control programme lowers weekly hamstring, knee and ankle injury prevalence compared with an adductor strength programme or self-selected injury prevention exercises in adolescent and adult amateur football players: a two-armed cluster-randomised trial with an additional comparison arm.

OBJECTIVE: To evaluate the preventive efficacy of an extended version of the Knee Control injury prevention exercise programme (IPEP) compared with an adductor strength programme and to a comparison group using a self-selected IPEP in amateur adolescent and adult male and female football players. METHODS: Two-armed cluster-randomised trial with an additional non-randomised arm. All 251 amateur teams (players 14-46 years) in one regional football district were approached. Teams meeting inclusion criteria were randomised to (1) extended Knee Control or (2) an adductor strength programme. Teams already using an IPEP were allocated to a comparison group and received no new intervention. Players responded to weekly questionnaires about football exposures and injuries during a 7-month season. RESULTS: Seventeen teams in the extended Knee Control, 12 in the adductor and 17 in the comparison group participated, with 502 players. For the primary outcomes, no difference in injury incidence in three lower-limb injury locations combined (hamstring, knee and ankle) was seen between extended Knee Control and the adductor group, whereas extended Knee Control had 29% lower incidence than the comparison group (incidence rate ratio 0.71, 95% CI 0.52 to 0.98). No between-group differences in groin injury incidence were seen. The weekly injury prevalence rates in the three lower limb locations combined (hamstring, knee and ankle) were 17% lower (prevalence rate ratio (PRR) 0.83, 95% CI 0.69 to 1.00) and 26% lower (PRR 0.74, 95% CI 0.63 to 0.87) in extended Knee Control compared with the adductor and comparison groups, respectively. CONCLUSION: No difference in injury incidence was seen between the extended Knee Control and the adductor programme whereas extended Knee Control reduced injury incidence by nearly one-third compared with a self-selected IPEP. Players in extended Knee Control had lower injury prevalence compared with an adductor or self-selected IPEP. TRIAL REGISTRATION NUMBER: NCT04272047; Clinical trials.

Neuromuscular control and hop performance in youth and adult male and female football players.

OBJECTIVES: To compare neuromuscular control and hop performance between youth and adult male and female football players. DESIGN: Cross-sectional study. PARTICIPANTS: 119 youth players (13-16 years; 68 males) and 88 adult players (17-26 years; 44 males). MAIN OUTCOME MEASURES: Neuromuscular control assessed with drop vertical jump (DVJ) and tuck jump assessment (TJA). Hop performance assessed with single-leg hop for distance and side hop. RESULTS: Adult females had smaller normalized knee separation distances (NKSD) during DVJ at initial contact (77.9 ± 18.5 vs. 86.1 ± 11.0, p = 0.010) and at maximum knee flexion (59.7 ± 23.4 vs.74.1 ± 18.1, p = 0.001) compared to youth females. TJA revealed more technique errors in youths compared to adults (males 10 (8-11) vs. 8 (7-10); females 11 (9-12) vs. 9 (8-11), p < 0.05). Youths demonstrated inferior hop performance (males single-leg hop 142 ± 18 vs. 163 ± 17, side hop 41 ± 12 vs. 52 ± 12, p < 0.001; females side hop 32 ± 10 vs. 38 ± 14, p < 0.05). CONCLUSIONS: Youth players demonstrated reduced neuromuscular control during TJA and inferior hop performance compared to adult players. Adult female players demonstrated greater knee valgus during DVJ compared to youth female players.

High compliance with the injury prevention exercise programme Knee Control is associated with a greater injury preventive effect in male, but not in female, youth floorball players.

PURPOSE: Evaluate team and player compliance with the Knee Control injury prevention exercise programme, study the association between player compliance and injury rates, and compare coach demographics, baseline prevention expectancies, and programme utilisation between teams with high and low compliance. METHODS: Prospective one-season cohort study based on a cluster randomised controlled trial on 301 (107 female) floorball players aged 12-17 years. Floorball exposure and injuries were self-reported weekly by players using the Oslo Sports Trauma Research Center questionnaire. Team and player compliance to Knee Control was reported monthly by coaches. Additionally, coaches answered pre- and post-season surveys. Teams were divided into a high (≥ 80%) or low (< 80%) compliance group based on their use of Knee Control during the season. Players were divided into three compliance groups based on their average weekly number of Knee Control sessions; high (≥ 2 sessions), intermediate (≥ 1 to < 2 sessions), and low dose (< 1 session). RESULTS: Mean team compliance for the high and low compliance groups were 95% (range 82-100) and 50% (range 13-66), respectively. Mean ± SD weekly Knee Control dose in the three player compliance groups were 2.4 ± 0.3, 1.4 ± 0.3, and 0.7 ± 0.3 sessions, respectively. There were no differences in total injury incidence between the player compliance groups, but players in the high-dose group had a 35% lower prevalence of injuries overall [adjusted prevalence rate ratio (PRR) 0.65, 95% CI 0.48-0.89] and 60% lower prevalence of substantial injuries (adjusted PRR 0.40, 95% CI 0.26-0.61) compared with the low-dose group. Male players in the high-dose group had consistently lower injury incidence and prevalence, while no between compliance group differences were seen in female players. There were no differences in sex, years of coaching experience, or baseline prevention expectancies in general between coaches for teams in the high vs. low compliance groups, but teams in the high compliance group had a better utilisation fidelity. CONCLUSION: There was a clear dose-response relationship between more frequent Knee Control use and lower injury rates in male floorball players, but not in female players. Teams with higher compliance also showed a better utilisation fidelity with the programme. LEVEL OF EVIDENCE: Level II.

Illness prevalence and symptoms in youth floorball players: a one-season prospective cohort study involving 471 players.

OBJECTIVE: To describe weekly illness prevalence and illness symptoms by sex in youth floorball players during one season. DESIGN: Prospective cohort study. SETTING: Players who were registered to play community level floorball during the 2017-2018 season (26 weeks) in two provinces in southern Sweden. PARTICIPANTS: 471 youth players aged 12-17 years. Mean (SD) age for 329 male players 13.3 (1.0) years and 142 female players 13.7 (1.5) years. PRIMARY AND SECONDARY OUTCOME MEASURES: Weekly self-reported illness prevalence and illness symptoms according to the 2020 International Olympic Committee's consensus recommendations. RESULTS: 61% of youth floorball players reported at least one illness week during the season, with an average weekly illness prevalence of 12% (95% CI 10.8% to 12.3%). The prevalence was slightly higher among females (13%, 95% CI 11.6% to 14.3%) than males (11%, 95% CI 9.9% to 11.7%), prevalence rate ratio 1.20 (95% CI 1.05 to 1.37, p=0.009). In total, 49% (53% male, 43% female) of illness reports indicated that the player could not participate in floorball (time loss), with a mean (SD) absence of 2.0 (1.7) days per illness week. Fever (30%), sore throat (16%) and cough (14%) were the most common symptoms. Female players more often reported difficulty in breathing/tight airways and fainting, and male players more often reported coughing, feeling tired/feverish and headache. Illness prevalence was highest in the peak winter months (late January/February) reaching 15%-18% during this period. CONCLUSIONS: Our novel findings of the illness prevalence and symptoms in youth floorball may help direct prevention strategies. Athletes, coaches, parents and support personnel need to be educated about risk mitigation strategies. TRIAL REGISTRATION NUMBER: NCT03309904.

Disease prevalence and number of health care visits among members of a nationwide sports organization compared to matched controls.

BACKGROUND: Physical activity has positive effects on several diseases and may reduce the risk of morbidity and the mortality rate. Whether the prevalence of disease and health care consumption differ between the members of sports organizations and the general population has not been established. Hence, this pilot study aimed to compare the prevalence of diseases known to be associated with physical inactivity and health care consumption in members of a large non-profit sports organization and an age-, sex- and geographically matched random sample from the general population. METHODS: Subjects in two Swedish cities who exercised at least once a week and had been members for at least two years in the non-profit sports organization Friskis&Svettis were invited. A randomized age-, sex- and geographically matched sample was drawn from the general population. Data on disease prevalence (by International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10) codes) and health care consumption were retrieved using the members' personal identification numbers through a regional health care database. Between-group differences in the prevalence of disease were compared using chi2-tests and logistic regression between members and controls. Health care consumption was defined as the number of visits, stratified by primary and hospital care, and was compared using chi2-tests and Mann-Whitney U-tests. RESULTS: In total, 3015 subjects were included in each group (response rate 11%). Controls had higher prevalence rates of musculoskeletal diseases (13.3% vs. 11.6%, p = 0.047), metabolic disease (10.4% vs. 5.4%, p < 0.001), hypertension (16.6% vs. 11.7%, p < 0.001), psychiatric diseases (8.9% vs. 7.1%, p = 0.012) and lung cancer (0.4% vs. 0%, p = 0.001) than the members. The total number of health care contacts was 22% higher in the controls than in the members, whereas the proportion of subjects with at least one health care visit was larger in the members (89% vs. 79%, p < 0.001). CONCLUSIONS: The prevalence rates of lifestyle diseases related to musculoskeletal, metabolic and psychiatric diseases, hypertension and lung cancer, and the overall health care consumption, were lower among members of a sports organization than among controls. However, longitudinal studies are needed to establish a cause-effect relationship between membership and disease development.

Intra- and interrater reliability of subjective assessment of the drop vertical jump and tuck jump in youth athletes.

OBJECTIVES: To investigate intra- and interrater reliability of the subjective assessments of filmed DVJ and TJA in youth male and female soccer players and to compare subjective assessment of the DVJ with two-dimensional movement analysis. DESIGN: Cross-sectional study. PARTICIPANTS: 115 soccer players (66 boys, 49 girls) mean age 14 ± 1 (range 13-16) years. MAIN OUTCOME MEASURES: Knee control during landing phase of DVJ was assessed using a 3-graded scoring scale. TJA was assessed according to ten criteria using a dichotomous grading scale. Subjective assessment of DVJ was compared with calculation of normalized knee separation distance (NKSD). RESULTS: Intrarater reliability for DVJ was substantial to almost perfect (kappa 0.72 rater 1; 0.85 rater 2). Interrater reliability was substantial to almost perfect (kappa from 0.68 to 0.83). The TJA total score intrarater reliability was ICC 0.59 for rater 1 and 0.90 for rater 2. Interrater reliability ranged from ICC 0.51 to 0.60. There were between-group differences in mean NKSD during DVJ for players rated as 0, 1 and 2, but within-group variability was large. CONCLUSION: Assessment of DVJ and TJA in youth athletes was rater dependent. Players with subjectively assessed reduced or poor knee control had smaller normalized knee separation distance in DVJ.

Performance on sprint, agility and jump tests have moderate to strong correlations in youth football players but performance tests are weakly correlated to neuromuscular control tests.

PURPOSE: This study aimed at evaluating the correlation between seven different performance tests and two neuromuscular control tests in youth football players and to evaluate the influence of sex and age groups on test results. METHODS: One-hundred and fifteen football players (66 boys, 49 girls) mean age 14 ± 0.7 (range 13-16) years from youth teams were tested at the start of the second half of the competitive season. A test battery including agility t-test, 505 agility test, single-leg hop for distance test, side-hop test, countermovement jump test, 10-m sprint test, 20-m sprint test, tuck jump assessment (TJA) and drop vertical jump (DVJ) was completed. RESULTS: Correlations between the seven different performance tests of agility, jump and sprint ability were generally moderate to strong (r = 0.534-0.971). DVJ did not correlate with the performance tests (rho = 0.004 to - 0.101) or with TJA total score (rho = 0.127). There were weak to moderate correlations between TJA total score and the performance tests (r = - 0.323-0.523). Boys performed better than girls in all performance tests (p < 0.001) and in TJA total score (p = 0.002). In boys, older players performed better than younger players in the majority of the tests, while there was no clear age influence among girls. CONCLUSION: Sprint performance was moderately to strongly correlated with agility and jump performance, and performance tests were weakly to moderately correlated to TJA, while DVJ did not correlate with the other tests. Boys performed better than girls on performance tests and TJA. An age effect on performance was evident in boys but not in girls. LEVEL OF EVIDENCE: Level IV TRIAL REGISTRATION: Clinical Trials gov identifier: NCT03251404.

Performance Effects with Injury Prevention Exercise Programmes in Male Youth Football Players: A Randomised Trial Comparing Two Interventions.

BACKGROUND: Increased performance from injury prevention exercise programmes (IPEPs) may affect injury risks positively and support the implementation of IPEPs. The primary aim was to study the performance effects of injury prevention exercises from two different IPEPs, the Knee Control IPEP and the further developed Knee Control+ IPEP, in youth male football players, and the secondary aim was to compare potential differences in performance effects between the IPEPs. METHODS: Four male youth football teams were tested for agility, hop and sprint performance at the start of the second half of the competitive season and after the end of the 8-week season. Per randomisation, two teams used Knee Control and two teams Knee Control+. RESULTS: In total, 47 players executed a median of 13 IPEP sessions (range 11-21 sessions). No improvements in performance were seen in the group as a whole. The intervention groups showed small declines in sprint and agility performance. There was a significant between-group difference in change for the 505 agility test, with improved performance in the Knee Control and worse performance in the Knee Control+ group, ΔKC vs KC+ = - 0.012 (95% CI - 0.19 to -0.04), d = 0.98. CONCLUSIONS: No clinically meaningful performance effects were seen from the Knee Control or Knee Control+ IPEP in youth male athletes and no meaningful differences were seen between Knee Control and Knee Control+ regarding effects on performance tests. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT03251404 . Registered on 16 August 2017.

Resistance training decreases plasma levels of adipokines in postmenopausal women.

Physical inactivity and the onset of menopause increase the risk of cardiovascular disease amongst postmenopausal women. We aim to investigate the effect of resistance training (RT) on plasma levels of selected cytokines, adipokines, myokines, and sex hormones in postmenopausal women with vasomotor symptoms. This was a sub-study of a randomised controlled trial investigating the effects of RT on vasomotor symptoms in postmenopausal women. Women were randomised to join a 15-week RT program (n = 26) or remain sedentary as control (n = 29). Venous blood samples were taken at week-0 and week-15 for all participants. Enzyme-linked immunosorbent assays and multiple bead assays were used to measure cytokines, adipokines, myokines, and sex hormones in plasma. Plasma measurements of 16 of 33 analytes were within detectable limits. After adjusting for good compliance in the RT group (58% of RT participants), after 15 weeks, significantly lower plasma levels of adiponectin (p < 0.001), lipocalin-2 (p < 0.01) and resistin (p = 0.04) were found. Comparing control and RT women, using change-over-time values, significant increases in median testosterone and sex hormone binding globulin levels were seen in RT women. RT intervention lowers the levels of adipokines, particularly adiponectin, in postmenopausal women with vasomotor symptoms. These results were secondary outcomes of a clinical trial, and further investigations in a larger cohort are essential with the additional control of diet control and body composition analyses. Nevertheless, our study shows RT may be a beneficial intervention in reducing inflammation amongst postmenopausal women.