Quantifying Hitting Load in Racket Sports: A Scoping Review of Key Technologies.

PURPOSE: This scoping review aims to identify the primary racket and arm-mounted technologies based on inertial measurement units that enable the quantification of hitting load in racket sports. METHODS: A comprehensive search of several databases (PubMed, SPORTDiscus, Web of Science, and IEEE Xplore) and Google search engines was conducted following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) extension for scoping reviews guidelines. Included records primarily focused on monitoring hitting load in racket sports using commercialized racket or arm-mounted inertial sensors through noncompetitive and competitive racket-sports players. RESULTS: A total of 484 records were identified, and 19 finally met the inclusion criteria. The largest number of systems found were compatible with tennis (n = 11), followed by badminton (n = 4), table tennis (n = 2), padel (n = 1), and squash (n = 1). Four sensor locations were identified: grip-attached (n = 8), grip-embedded (n = 6), wrist (n = 3), and dampener sensors (n = 2). Among the tennis sensors, only 4 out of the 11 (36.4%) demonstrated excellent reliability (>.85) in monitoring the number of shots hit either during analytic drills or during simulated matches. None of the other racket-sports sensors have undergone successful, reliable validation for hitting-volume quantification. CONCLUSIONS: Despite recent advancements in this field, the quantification of hitting volume in racket sports remains a challenge, with only a limited number of tennis devices demonstrating reliable results. Thus, further progress in technology and research is essential to develop comprehensive solutions that adequately address these specific requirements.

Time-loss Injuries among Female and Male Spanish Rink Hockey Players.

The present study describes the time-loss injuries among female and male athletes of the Spanish rink hockey league during the 2021/22 season.We performed a retrospective cohort study on time-loss injuries, whereby the athlete is prevented from participating in a training session or game because of the injury.A total of 463 athletes were included, with 326 (70.4%) senior male and 137 (29.6%) female. Two hundred and eighty-two time-loss injuries were recorded, the most common form being muscle injuries (112 episodes, 39.7%), especially those affecting the hip adductor muscles (52 episodes, 46.4% of muscle injuries). Most injuries were classified as mild (1-7 days of time-loss) and the median return-to-play was 9.5 days (range 1-180).Injury patterns were compared according to gender, position and moment: the results showed significant differences between senior males and females, between field players and goalkeepers, as well as between training and game, in terms of injury nature and type. The injury incidence proportion was significantly higher for field players compared to goalkeepers), and senior males had a significantly higher risk than senior females.The present study provides a starting point for studying and preventing injuries in rink hockey athletes.

Analysis of injuries during the 2019 Rink Hockey World Championship.

OBJECTIVES: The purpose of this study is to describe the incidence and characteristics of injuries at the 2019 Rink Hockey World Championship. METHODS: A cross-sectional study was performed among rink hockey athletes from three National Teams (Argentina, Portugal, and Spain). All injuries were reported by the medical staff of each National Team during the preparation period and the competition in the 2019 World Championship (Barcelona, Spain). Injury rate was calculated as the number of injuries per 1000 hours of player-hours of exposure. RESULTS: A total of 91 players (n = 61, 67% male; and n = 30, 33% female) participated in the study: 31 Senior Male (34%), 30 Senior Female (33%), and 30 Under-19 Male (33%). A total of 54 games were played by 9 teams from 3 countries, comprising of 4562 and 4380 hours of total athletic game and training exposure recorded, respectively. Fifty-one injuries (20 injuries with time-loss and 31 medical attention -injuries with no time-loss) were reported. The overall injury incidence rate was 11.2/1000 hours (95% CI, 8.5-14.7). The injury incidence during games (27.5; 95% CI, 11.6-65.2) was higher than the injury incidence during training sessions (3.4; 95% CI, 2-5.7). The incidence rate for game for the entire study period was 8.19 times higher (95% CI, 2.61-21.36) than that for training. The global injury burden was 45.4 days/1000 hours for a total exposure time. Acute was the most frequently documented onset and the non-contact was the most common mechanism. The most frequently reported injuries were head contusion (n = 5, 25%), followed by thigh injuries (n = 3, 15%). CONCLUSIONS: The injury incidence reported in a Rink Hockey international competition was 11.2/1000 hours. The risk of injury was higher during games than during training. Prevention strategies for injuries in these kinds of championships may be worth discussing. The craniofacial injuries were the most frequently reported.

Data set on mortality of national basketball association (NBA) players.

In this work, we present a data set on the survival times and mortality rates of all 4374 professional basketball players who participated in the National Basketball Association (NBA) from its inception in 1946 until July 2019 [1]. It contains the data of 412 active and 3962 former players. The data were recorded from different internet sources and include information on each player's position, ethnicity, handedness, ages at NBA debut and career end, height, weight, or number of NBA games. The results of the analysis of a previous data set with the same variables of all NBA players from 1946 to 2015 were recently published by Martinez et al. in 2019 [2]. The information provided in the data set can be useful to better understand the mortality risk among NBA players.

Use of GPS to measure external load and estimate the incidence of muscle injuries in men's football: A novel descriptive study.

Measurement of external load in players provides objective information to optimise the weekly balance between training and recovery to improve performance and prevent injuries. Our aim was to evaluate the incidence of sports-related muscle injuries of the lower limb in relation to external load, measured by global positioning system (GPS), in football players. A descriptive study was carried out. Data were collected from 71 professional male football players (30 professionals and 41 youth players) from an elite football club competing in the Spanish and European League in the 2017-2018 season. As external load variables, we measured High Metabolic Load Distance (HMLD), High Speed Running (HSR), Player Load (PL), and Total Distance (TD) through GPS. Injury rate (IR) was calculated both in relation to such GPS load metrics and to load exposure time. We considered categories (youth and professional), playing positions (centre back, full back, midfielder, and forward), and training day with respect to match-day (-4MD, -3MD, -2MD, -1MD, MD, +1MD, +2MD). The GPS load metrics HMLD, HSR, PL, and TD showed very similar patterns across categories and positions, but varied according to training session or MD. The highest loads were observed on MD and three days prior to the match (-3MD). Similarly, the overall IR, both calculated per load exposure time and per GPS load metrics, was highest on MD and -3MD. Again, no differences were observed between youth and professional players. Midfielders demonstrated the highest IR in all metrics, followed by the forwards. In conclusion, this study suggests that external load and incidence of muscle injuries are directly proportional. Therefore, the measurement of more external load variables other than load exposure time, such as the GPS metrics HMLD, HSR, PL, and TD may help to describe the pattern and magnitude of injuries. Future studies based on ours may help to further improve the understanding of the incidence of muscle injuries on the basis of external loads measurements in different football teams.

Past-season, pre-season and in-season risk assessment of groin problems in male football players: a prospective full-season study.

OBJECTIVE: We assessed past-season, pre-season and in-season risk factors to investigate their association with an in-season groin problem in male amateur football players. METHODS: Past-season groin-pain information and pre-season short-lever and long-lever adductor squeeze strength were obtained at baseline, together with anthropometrics (weight, lower limb lever length) and player age. In-season hip-related and groin-related sporting function was monitored every 4 weeks using the Sports and Recreation (Sport) subscale from the Hip And Groin Outcome Score questionnaire (HAGOS (Sport)). Groin problems, including time-loss groin injuries and groin pain irrespective of time loss, were collected over a 39-week competitive in-season. We estimated relative risk (RR), and 95% credibility interval (ICr) from logistic regressions fitted in a Bayesian framework. RESULTS: Players (n=245) suffering from groin pain during the past-season had 2.4 times higher risk of experiencing a groin problem in the new season (2.40 RR; 95% ICr 1.5 to 3.7). This risk was reduced by 35% (0.65 RR; 95% ICr 0.42 to 0.99) per unit (N·m/kg) increase in the long-lever adductor squeeze test. Player age, short-lever squeeze test and the HAGOS (Sport) scores were not associated with the risk of a groin problem. CONCLUSIONS: Past-season groin pain increased the risk of a groin problem in the new in-season. This risk was reduced by higher pre-season long-lever adductor squeeze strength. Past-season groin-pain information and long-lever adductor squeeze strength can be quickly obtained during pre-season to identify players with an elevated risk of in-season groin problems. This may be key to reduce these problems in the new season.

Impacts of ambient temperature and seasonal changes on sports injuries in Madrid, Spain: a time-series regression analysis.

OBJECTIVES: Recreational physical activity is an integral part of our society, and the injuries caused by sports activities are a concern for public health. We studied the effect of outdoor ambient temperature on hospital emergency department visits caused by sports injuries in Madrid, Spain, and accounted for its seasonal changes. METHODS: We used a time-series design. Data was analysed with quasi-Poisson regression models. We calculated the proportion of emergency visits attributable to seasonal changes before and after adjusting for daily ambient temperature. We modelled the association between emergency visits and temperature using distributed lag non-linear models. RESULTS: The proportion of emergency visits attributable to seasonal changes was 24.1% and decreased to 7.6% after adjusting for temperature. We found a high risk of emergency visits associated with cold and hot temperatures, whereas the risk was higher for heat. CONCLUSION: Sports and recreational physical activity injuries are not rare events; therefore, appropriate healthcare decisions should consider the impact of outdoor ambient temperature and seasonal changes.

The use of recovery strategies by Spanish first division soccer teams: a cross-sectional survey.

OBJECTIVES: different active and passive post-exercise recovery techniques such as massage, foam rolling, stretching or ice baths among others, are used by elite athletes to promote effective physiological, physical, and mental restoration. However, limited research is available investigating the use of recovery strategies in professional soccer. As such, we aimed to explore and describe the use of strategies by professional teams throughout the season, describing competitive and preparatory phases. METHODS: the present study collected data from all professional Spanish soccer teams who played in 'LaLiga' (The Spanish first division), during the season 2018-2019 (n = 20) and the ones promoted for the season 2019-2020 (n = 3). A six-section online survey was responded once. RESULTS: teams used different recovery protocols and combinations, although natural and physical strategies such as sleep/nap, food/fluid replacement, cold/ice bath/shower/immersion, and massage were always present. However, there is no agreement in the protocols and timings employed. Three physical strategies showed a higher presence in the recovery protocols after competition: cold/ice bath/shower/immersion, massage and foam rolling; always used by seventeen teams (74%), sixteen (70%) and thirteen (57%) respectively. The design and supervision of recovery are multidisciplinary tasks in 87% of the teams. Our findings also demonstrate that although there is a body of scientific evidence on recovery, a gap between theory and practice exists with 13% of the teams acknowledging that insufficient logistics and economic resources limit the use of some strategies, and two teams (9%) not periodizing or individualizing recovery. CONCLUSION: the investigation provided insight into the current use of recovery strategies by 'LaLiga' teams, highlighting that all clubs used them to one extent or another, but also that significant variability responding to individualized perceptions exists. Moreover, this study provides relevant contextual information that may be useful for professional soccer staff concerning the use of recovery strategies.

Groin problems from pre- to in-season: a prospective study on 386 male Spanish footballers.

This study investigated the weekly prevalence of groin problems over a 3-week football pre-season, compared to a 39-week competitive in-season. We registered time-loss groin injuries, and self-reported weekly groin-pain in 17 amateur male football teams (386 players). The average weekly prevalence of groin problems (prevalence ratio (PR)) was 1.8 times higher (95% CI 1.6 to 2.0) during pre-season (21%) compared to in-season (12%). We found a higher weekly prevalence (PR 1.8; 95% CI 1.6 to 2.1) of groin problems without time loss, during the pre-season (19%) compared to the in-season (10%), but no significant difference in the weekly prevalence of groin problems with time loss (PR 1.5; 95% CI 1.0 to 2.4). Attention should be given to optimal load progression, and early implementation of preventive measures during the football pre-season to reduce the prevalence of groin problems in both pre- and in-season.

Higher training workloads do not correspond to the best performances of elite basketball players.

The aim of this study was to identify the correspondence between the workload demands in training sessions and the game performance from elite basketball players, according to their specific positions. Data were collected from a professional men's basketball team competing in the Spanish Professional League and Euroleague. Players' activity during the training sessions was measured using WIMU PRO® and the game statistics were used as a measure of game performance. Cluster analysis allowed to classify the training workload and the game performance, whereas correspondence analysis allowed to explore their relationship. In essence, there was no correspondence from the higher workloads with the best performances, on the contrary, the small forwards' best performances corresponded to lower training workouts. Despite their importance, the external measures of load need to be complemented with additional (and valid) measures that can be translated to game performance.

Performance changes during the off-season period in football players - Effects of age and previous hamstring injury.

The aims of this study were to investigate changes in selected performance measures during an off-season period, their association, and the potential role of age and previous hamstring injury in semi-professional and amateur football players. Seventy-four male players (age: 25 ± 4 years, stature: 178.0 ± 6.6 cm, body mass: 74.9 ± 8.1 kg) were assessed at the beginning and end of the off-season summer-period for sprint, change-of-direction performance and eccentric hamstring strength. Small to medium increases in sprint times were observed at 5 (d = 0.26, p = 0.057), 10 (d = 0.42, p < 0.001) and 30 m (d = 0.64, p < 0.001). Small (d = -0.23, p = 0.033) improvements were observed for COD performance, and no changes in eccentric hamstring strength (d = 0.10, p = 0.317). The changes in the outcomes were not affected by age (p = 0.449 to 0.928) or previous hamstring injury (p = 0.109 to 0.995). The impaired sprint performance was not related to changes in eccentric hamstring strength (r = -0.21 to 0.03, p = 0.213 to 0.856), instead, changes in COD performance were associated with changes in eccentric hamstring strength (r = -0.42, p = 0.008).

Statement on Methods in Sport Injury Research From the First METHODS MATTER Meeting, Copenhagen, 2019.

SYNOPSIS: High-quality sports injury research can facilitate sports injury prevention and treatment. There is scope to improve how our field applies best-practice methods-methods matter (greatly!). The first METHODS MATTER meeting, held in January 2019 in Copenhagen, Denmark, was the forum for an international group of researchers with expertise in research methods to discuss sports injury methods. We discussed important epidemiological and statistical topics within the field of sports injury research. With this opinion document, we provide the main take-home messages that emerged from the meeting. Meeting participants agreed that the definition of sport injury depends on the research question and context. It was considered essential to be explicit about the goal of the research effort and to use frameworks to illustrate the assumptions that underpin measurement and the analytical strategy. Complex systems were discussed to illustrate how potential risk factors can interact in a nonlinear way. This approach is often a useful alternative to identifying single risk factors. Investigating changes in exposure status over time is important when analyzing sport injury etiology, and analyzing recurrent injury, subsequent injury, or injury exacerbation remains challenging. The choice of statistical model should consider the research question, injury measure (eg, prevalence, incidence), type and granularity of injury data (categorical or continuous), and study design. Multidisciplinary collaboration will be a cornerstone for future high-quality sport injury research. Working outside professional silos in a diverse, multidisciplinary team benefits the research process, from the formulation of research questions and designs to the statistical analyses and dissemination of study results in implementation contexts. This article has been copublished in the British Journal of Sports Medicine and the Journal of Orthopaedic & Sports Physical Therapy. J Orthop Sports Phys Ther 2020;50(5):226-233. doi:10.2519/jospt.2020.9876.

Differences in Physical Demands between Game Quarters and Playing Positions on Professional Basketball Players during Official Competition.

The purpose of this study was to compare physical demands between game quarters and specific playing positions during official basketball competition. Thirteen professional male basketball players from the Spanish 2nd Division were monitored across all 17 regular-season home games. Physical demands were analyzed using a local positioning system (WIMU PRO™, Realtrack Systems S.L., Almería, Spain) and included peak velocity, total distance covered, high-speed running (>18 km·h-1), player load, jumps (>3G), impacts (>8G) and high-intensity accelerations (≥2 m·s-2) and decelerations (≤-2 m·s-2). A linear mixed model was used to test statistical significance (p < 0.05) between independent variables. Furthermore, standardized Cohen's effect size (ES) and respective 90% confidence intervals were also calculated. There was an overall decrease in all variables between the first and fourth quarter during competition. Specifically, total distance covered (p < 0.001; ES = -1.31) and player load (p < 0.001; ES = -1.27) showed large effects between the first and last period. Regarding differences between positions, guards presented significant increased values compared to centers (p = 0.04; ES = 0.51), whereas centers achieved significant larger results and moderate effects in comparison to guards in peak velocity (p = 0.01; ES = 0.88) and jumps (p = 0.04; ES = 0.86). In conclusion, physical demands vary between game quarters and playing positions during official competition and these differences should be considered when designing training drills to optimize game performance.

Statement on methods in sport injury research from the 1st METHODS MATTER Meeting, Copenhagen, 2019.

High quality sports injury research can facilitate sports injury prevention and treatment. There is scope to improve how our field applies best practice methods-methods matter (greatly!). The 1st METHODS MATTER Meeting, held in January 2019 in Copenhagen, Denmark, was the forum for an international group of researchers with expertise in research methods to discuss sports injury methods. We discussed important epidemiological and statistical topics within the field of sports injury research. With this opinion document, we provide the main take-home messages that emerged from the meeting.

Methods matter: exploring the 'too much, too soon' theory, part 1: causal questions in sports injury research.

BACKGROUND: It is widely accepted that athletes sustain sports injury if they train 'too much, too soon'. However, not all athletes are built the same; some can tolerate more training than others. It is for this reason that prescribing the same training programme to all athletes to reduce injury risk is not optimal from a coaching perspective. Rather, athletes require individualised training plans. In acknowledgement of athlete diversity, it is therefore essential to ask the right causal research question in studies examining sports injury aetiology. PURPOSE: In this first part of a British Journal of Sports Medicine educational series, we present four different causal research questions related to the 'too much, too soon' theory and critically discuss their relevance to sports injury prevention. CONTENT: If it is true that there is no 'one size fits all' training programme, then we need to consider by how much training can vary depending on individual athlete characteristics. To provide an evidence-base for subgroup-specific recommendations, a stronger emphasis on the following questions is needed: (1) How much training is 'too much' before athletes with different characteristics sustain sports-related injury? and (2) Does the risk of sports injury differ among athletes with a certain characteristic (eg, high experience) compared with athletes with other characteristics (eg, low experience) depending on how much training they perform? CONCLUSION: We recommend that sports injury researchers aiming to examine the 'too much, too soon' theory should carefully consider how they, assisted by coaches, athletes and clinicians, pose their causal research question. In the light of the limitations of population-based prevention that intends to provide all athletes with the same advice, we argue that a stronger emphasis on research questions targeting subgroups of athletes is needed. In doing so, researchers may assist athletes, clinicians and coaches to understand what training advice/programme works best, for whom and under what circumstances.

Prevalence and severity of groin problems in Spanish football: A prospective study beyond the time-loss approach.

The time-loss definition of injury is commonly adopted in epidemiological groin-injury studies in football, with a significant risk of underestimating the impact of these injuries. This study investigated the extent of groin problems, beyond the time-loss approach, over a full Spanish football season. Players from 17 amateur male teams were followed over 39 consecutive weeks. Groin-injury time loss and self-reported groin pain, irrespective of time loss, were combined to calculate the average weekly prevalence of all groin problems with or without time loss. A subscale measuring hip- and groin-related sporting function from the Copenhagen Hip and Groin Outcome Score questionnaire (HAGOS, Sport/Rec) was registered every 4 weeks. In total, 407 players participated in the study. The average (range) weekly prevalence of all groin problems was 11.7% (7.2%-20.8%); 1.3% with time loss (0.0%-3.2%) and 10.4% without time loss (6.3%-17.6%). Players with groin problems reported lower scores (mean difference) on the HAGOS, Sport/Rec subscale compared with players without (-19.5 [95% CI: -20.7 to -18.4]), while there was no difference between players reporting groin problems with and without time loss (4.0 [95% CI: -1.1 to 9.1]). The traditional time-loss measure only captured 10% of all groin problems. Hip- and groin-related sporting function was not different between players reporting groin problems with or without time loss, suggesting the reason for continuing to play is not only related to the severity of symptoms. These findings question the judicious use of the time-loss approach in overuse conditions, such as groin pain in footballers.

Incidence of Tendinopathy in Team Sports in a Multidisciplinary Sports Club Over 8 Seasons.

Tendinopathy is a critical medical condition that often hinders level of participation for professional and young athletes in many sports. The purpose of the study was to describe the incidence and severity of tendinopathy in a multi-sport club with professional and youth teams. We performed a retrospective epidemiological study. Incidence of tendinopathy in players (n = 3839; 8-38 years, professional and youth) was reviewed over 8 seasons (2008-2016) in 5 team sports: football, basketball, handball, roller hockey, and futsal. Team physicians diagnosed and classified tendinopathies according to anatomical location, sport types, playing category, sex, playing surface, lost training time, and severity (time to return to play). Injuries were coded using OSICS-10, and incidence of tendinopathies were calculated as the number of injuries per 100 players per season. The total relative frequency of tendinopathy (versus total injuries) was 22% (843/3839) over 8 seasons from 360 in youth and 483 in professional teams. The incidence of injury was the highest in professional basketball [69.9, 95%CI: (58.0-81.4)] followed by professional roller hockey [64.4, 95%CI: (47.3-85.6)], and professional futsal [36.2, 95%CI: (27.3-47.1)]. The most incidences commonly affected tendons were the patellar [11.7, 95%CI: (10.0-13.5)] and Achilles [10.3, 95%CI: (8.5-12.5)]. Tendinopathies represent a significant number of injuries in team sports and are more common in professional than youth teams, especially basketball and roller hockey. Additional studies are needed to understand associated time-loss and impact on performance, and to develop prevention strategies for high risk sports.

Ankle Sprain Versus Muscle Strain Injury in Professional Men's Basketball: A 9-Year Prospective Follow-up Study.

BACKGROUND: Ankle sprain is the most common injury in basketball players. However, in our routine clinical evaluation, we observe a high frequency of muscle injury. Currently, no reliable information is available regarding the magnitude of these types of injury. PURPOSE: To describe the type and rate of muscle injuries in male basketball players and discuss clinical management and prevention strategies. STUDY DESIGN: Descriptive epidemiology study. METHODS: A total of 59 professional male basketball players were evaluated over 9 seasons (2007-2015). All injuries during the study period were registered through use of a validated electronic medical record system. RESULTS: We analyzed 463 injuries, of which 207 resulted in time loss and 256 required medical attention, for a total exposure time of 42,678 hours for the 59 players involved in the study. Muscle strains and ankle sprains accounted for 21.2% (n = 98) and 11.9% (n = 55) of all injuries, respectively. The global incidence rate was 10.8 injuries per 1000 player-hours (95% CI, 9.9-11.9). The global injury burden was 53.9 days lost due to injuries per 1000 hours for a total exposure time. The incidence rate of muscle strains (2.3; 95% CI, 1.9-2.8) was higher than that of ankle sprains (1.3; 95% CI, 1-1.7). The incidence rate for muscle injuries for the entire study period was 1.8 times higher (95% CI, 1.28-2.49) than that for ankle sprains. CONCLUSION: In this study, muscle injuries were more commonly observed compared with ankle sprains. Prevention strategies for muscle injuries may be worth discussing.