Sport Sampling Is Associated With Improved Landing Technique in Youth Athletes

Are Recreational Sports a Relic of the Past OR a Solution for the Future?

ABSTRACT

Children's participation in sport is a critical component to their physical and social development and as such, efforts should be made to provide all children with the opportunity to play. In recent years, there has been an observed shift in the focus of youth sports from that of participation for the health benefits of physical activity and fun to that of winning and competing. As a result, there has been a rise in club sports offerings and a subsequent reduction in recreational sports opportunities. This change presents unique challenges to children's access to sport and may not adequately support their overall physical, social, and emotional development. This commentary will discuss the benefits and barriers to increasing recreational sport opportunities using the Social Ecological Model as a framework. It also will propose solutions that can be implemented at the intrapersonal, interpersonal, organizational, community, and public policy levels to revive recreational sports.

Is There Just One Type of Multisport Pathway? A Scoping Review of Multisport Engagement in Early Athlete Development

Multisport engagement is positioned as the antithesis to specialization within youth development pathways. However, different terms are used to describe the multisport pathway, which may create confusion regarding what the pathway should look like. This review investigated all published research examining the multisport pathway, with a focus on terminology, and how different terms have led to varying interpretations of this research. Four databases were searched for all peer reviewed studies published up until December 2021. All included papers were full text, in English, and focusing on multisport athlete engagement. In total, 1974 abstracts were screened for inclusion eligibility, resulting in 82 articles included within this review. General results showed most studies are empirical (71%, n = 58) and looked at athlete development pathways using retrospective questionnaires aimed at investigating the specific pathway to sporting excellence. However, despite the consensus that multisport athletes play many sports in their lifetime, there is little investigation into when and the level of intensity (play versus practice) at which these sports are being played. Further, inconsistencies in the terminology used to describe this pathway have made it difficult to understand potential mechanisms that lead to any positive or negative effects. It is recommended that differences between the key terms of diversification and sampling are clarified and should not be regarded as synonymous as they may represent different paths within multisport development based on varying levels of intensity of play and practice.

The Relationship between Exercise Re-Participation Intention Based on the Sports-Socialization Process: YouTube Sports Content Intervention

Few studies have used a quantitative research methodology to examine the socialization process model, and such studies were conducted to verify a new model by intervening in the variables of YouTube sports content. To understand this process, we tested the moderated mediating effect by intervening in YouTube sports content based on the sports socialization process model. We recruited 274 participants from the Jeju Residents' Jeju Sports Festival, Korea. The PROCESS Macro program was performed to test the research hypotheses. The findings indicate that social support had a significant effect on re-participation intention. Social support had a significant mediation effect on exercise interruption intention, re-participation intention, and exercise performance satisfaction. Furthermore, through the relationship between social support and exercise interruption intention, YouTube sports content showed a significant interaction of re-participation intention in exercise. These results extend sports socialization theory by discovering a new model that explains the relationship between the sports socialization process and YouTube sports content. In addition, it will provide a basis for delivering educational information to the public so that they can recognize the importance of physical activity and exercise skills.

Association of sports sampling and training frequency with injury among school-age athletes in Japan

BACKGROUND

This study evaluated the status of sports participation and training frequency during school years to identify related factors for injuries in the general Japanese population.

METHODS

A total of 1,533 adult participants (762 males, 771 females) retrospectively completed a questionnaire assessing sports participation (single/multisport), training frequency (weekly days of sports participation), and injury history (acute and overuse) at each stage of school (elementary, junior high, and high school).

RESULTS

In total, 41.1% of participants reported playing multiple sports in elementary school; this rate decreased to 17.4% in junior high school and 8.9% in high school. Weekly days of sports participation were associated with almost all injuries at each age. Participants who still played multiple sports in junior high school had fewer overuse injuries in junior high school and high school (P = 0.017; odds ratio (OR) = 0.69; 95% confidence interval (CI) = 0.51-0.94; P = 0.006, OR = 0.66, 95% CI, 0.49-0.89, respectively). The ratio for sports sampling differed between elementary school and older ages. This trend was associated with the prevalence of overuse injuries.

CONCLUSION

Promoting sports sampling through junior high school ages and controlling the training frequency may decrease the occurrence of injuries in young athletes.

Physical Activity and Nutrition Intervention for Middle Schoolers (Move More, Get More): Protocol for a Quasi-Experimental Study

BACKGROUND

Physical activity and nutrition behaviors are important to reducing the prevalence of childhood obesity. Previous research has identified school-based interventions as effective strategies to improve physical activity and nutrition. However, the results are often mixed, and middle schoolers are an under-studied population.

OBJECTIVE

Our study aims to fill this gap by developing an after-school intervention to increase physical activity and fruit and vegetable consumption that is influenced by national guidelines and formative research.

METHODS

This study was an after-school, quasi-experimental study spanning 9 months. Enrollment began in September 2021 and continued on a rolling basis through February 2022. Weekly, middle schoolers were offered 2-3 physical activity sessions and 1 produce kit. Physical activity was measured using accelerometers and questionnaires. Nutrition behaviors were assessed using questionnaires, and physical literacy was assessed using researcher observations. Follow-up data collection occurred in December 2021 and in April 2022. Difference scores will be calculated and analyzed for each outcome variable.

RESULTS

The intervention started in September 2021 and will conclude in May 2022. Published study results are expected in late 2022.

CONCLUSIONS

An increase in physical literacy, physical activity, and fruit and vegetable consumption is expected. If successful, future studies will focus on reach and sustainability. Lastly, this study may serve as a model for improving health outcomes in middle schools.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/37126.

High School Sport Specialization and Injury in Collegiate Club-Sport Athletes

CONTEXT

Sport specialization during adolescence may affect future injury risk. This association has been demonstrated in some professional sport athletes.

OBJECTIVE

To determine the association between adolescent sport specialization levels in high school and injuries sustained during collegiate club sports.

DESIGN

Cross-sectional study.

SETTING

Paper and online surveys.

PATIENTS OR OTHER PARTICIPANTS

Collegiate club-sport athletes.

MAIN OUTCOME MEASURES(S)

An anonymous survey was administered from September 2019 to May 2020. The survey included sport specialization classification via a commonly used 3-point scale (low, moderate, high) for each high school year (9th-12th), high school sports participation, and collegiate club-sport injury history. The number of years (0-4) an individual was highly specialized in high school was calculated. Individuals who participated in the same sport in high school and college were compared with individuals who played a different sport in college than in high school. An injury related to sport club activities was classified as arising from a contact, noncontact, or overuse mechanism required and the individual to seek medical treatment or diagnosis. Injuries were classified into overuse and acute mechanisms for the upper extremity, lower extremity (LE), and head/neck.

RESULTS

Single-sport participation and the number of years highly specialized in high school sport were not associated with college club-sport injuries (P > .1). Individuals who played a different collegiate club sport than their high school sport were more likely to report an LE or head/neck acute injury compared with athletes who played the same collegiate and high school sport (LE = 20% versus 8%, χ2 = 7.4, P = .006; head/neck = 16% versus 3%, χ2 = 19.4, P < .001).

CONCLUSIONS

Adolescent sport specialization was not associated with reported injuries in collegiate club-sport athletes. Collegiate club-sport athletic trainers should be aware that incoming students exploring a new sport may be at risk for LE and head/neck acute injuries.

Parkour-Based Activities in the Athletic Development of Youth Basketball Players

While ideas from long-term athlete development (LTAD) models have been adopted and integrated across different sports, issues related to early specialization, such as increased risk of injury and burnout, are still common. Although some benefits may be associated with early sport specialization, sports sampling is purported to be a more effective approach to the long-term health and wellbeing of children. Furthermore, the concept of developing what are commonly referred to as "fundamental movement skills" (FMS) is central to the rationale for delaying single sports specialization. However, in place of sports sampling, it appears that the practice of strength and conditioning (S&C) has become a driving force behind developmental models for youth athletes, highlighted by the growing body of literature regarding youth athletic development training. In this perspective piece, we explore how conventional S&C practice may insufficiently develop FMS because typically, it only emphasizes a narrow range of foundational exercises that serve a limited role toward the development of action capabilities in youth athletic populations. We further discuss how this approach may limit the transferability of physical qualities, such as muscular strength, to sports-specific tasks. Through an ecological dynamics lens, and using basketball as an example, we explore the potential for parkour-based activity within the LTAD of youth basketball players. We propose parkour as a training modality to not only encourage movement diversity and adaptability, but also as part of an advanced strength training strategy for the transfer of conventional S&C training.

The prevalence of high school multi-sport participation in elite national football league athletes

Objectives: Early youth specialization is increasingly being researched and identified as a risk factor for overuse injuries and burnout. This study aimed to characterize high school sport specialization in top National Football League (NFL) athletes and determine whether associations exist between single-sport specialization and future injury risk, performance, and longevity.Methods: For NFL first-round draft picks from 2008-2017, data on the number of games played in the NFL, overuse injuries causing athletes to miss one or more regular season games, Pro Bowl selections, and current status in the NFL were collected using publicly available information.Results: A total of 318 athletes were analyzed. Multi-sport athletes were highly prevalent (88%, n = 280), while only 12% (n = 38) of athletes were classified as single-sport. No difference between multi-sport and single-sport athletes was found regarding games missed to upper (p = 0.93) or lower extremity injuries (p = 0.49), total games played (p = 0.57), or NFL longevity (p = 0.97). There was no significant difference in the proportions of athletes reaching at least 1 Pro Bowl.Conclusion: The majority of NFL first-round draft picks were multi-sport athletes in high school. Single-sport football participation in high school does not appear to aid athletes in reaching or succeeding in the NFL.

Early Sport Specialization

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Early sport specialization has been recognized as a potential factor in the relationship between physical activity and health since the early 1970s.

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There is no universally agreed-upon terminology or definition for early sport specialization, but early sport specialization typically encompasses preteen athletes who play 1 sport competitively throughout the year or play on several teams within 1 season, leading to intensive participation without variation in physical activity.

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There is a limited number of comprehensive long-term outcome studies that have identified a potential link between early sport specialization and musculoskeletal injury or burnout.

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Methodologically sound prospective research looking at chronologic age and years of participation by sports played will help to answer whether there is an impact from early sport specialization on the relationship with successful participation and injury occurrence.

Clinical Implications of Landing Distance on Landing Error Scoring System Scores

CONTEXT

The Landing Error Scoring System (LESS) screens for risk of noncontact anterior cruciate ligament injury. The LESS requires individuals to jump forward from a 30-cm box to a distance of 50% of their body height. However, different landing distances have been cited in the scientific literature.

OBJECTIVE

To examine whether landing distance influences LESS outcomes.

DESIGN

Cross-sectional study.

SETTING

Laboratory.

PARTICIPANTS OR OTHER PARTICIPANTS

Seventy young active individuals (34 males, 36 females).

INTERVENTION(S)

Participants performed 3 × 30-cm jump-landing tasks under 2 landing conditions in randomized order: (1) 50% of body height (d50%), (2) self-selected distance (dss).

MAIN OUTCOME MEASURE(S)

Mean LESS scores, proportions of individuals categorized at high (LESS: ≥ 5 errors) and low (LESS: < 5 errors) injury risk, and landing distances were compared between conditions using generalized estimating equations. Consistency of risk categorization was examined using odds ratios (ORs) and McNemar tests. McNemar and Wilcoxon signed rank tests were used to compare the occurrence of specific LESS errors.

RESULTS

Participants landed closer to the box under the dss condition (difference = -23.28 [95% CI = -20.73, -25.81]%, P < .001). Group mean LESS scores (difference = -0.01 [95% CI = -0.59, 0.57] error, P = .969) and risk categorization (OR = 0.94 [95% CI = 0.47, 1.88], P = .859) were similar between conditions. However, individual-level risk categorization was inconsistent in 33% of participants, as was the occurrence of specific errors.

CONCLUSIONS

Using dss during the LESS might lead to different LESS errors and risk categorizations at an individual level than using d50%. Given that individual LESS scores are of primary interest in clinical and sport settings and the injury-risk threshold has not been validated for dss, we recommend use of the original LESS protocol. When only group mean LESS scores or proportions of at-risk individuals are of interest, using dss is feasible to facilitate the testing of large cohorts.

Defining a research agenda for youth sport specialisation in the USA: the AMSSM Youth Early Sport Specialization Summit

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

High Specialization among Female Youth Soccer Players Is Associated with an Increased Likelihood of Serious Injury

PURPOSE

This study aimed to assess the associations between serious injury (≥3-month time loss) and level of specialization among high-level female soccer players and to compare the specialization and college commitment ages of female youth soccer players to Division I college and professional soccer athletes.

METHODS

Youth, college, and professional female soccer players in the United States playing in the top league at each level were recruited to complete an anonymous online survey. The survey collected information about player demographics, soccer specialization and training patterns, history of serious injuries from soccer, and perceptions surrounding soccer specialization. Comparisons between groups were performed using two-sample t-tests, χ2 analyses, and multiple logistic regression models controlling for differences in age. A P value of less than 0.05 was set as significant.

RESULTS

A total of 1,018 (767 youth, 251 college/professional) athletes completed the survey. Serious injuries affected 23.6% of youth and 51.4% of college/professional athletes. Anterior cruciate ligament tears were more prevalent in college/professional players compared with youth athletes (18.3% vs 4.0%; P < 0.001). Highly specialized youth athletes (66.5%) were more likely to have sustained a serious injury from soccer compared with athletes with low specialization (odds ratio, 2.28 (1.38-3.92); P = 0.008) but not moderate specialization (odds ratio, 1.37 (0.83-2.27); P = 0.43). A higher proportion of youth athletes specialized at a young age (≤10 yr) compared with college/professional players (44.2% vs 25.9%; P < 0.001).

CONCLUSIONS

High specialization in female youth soccer players is associated with an increased likelihood of sustaining a serious injury. Current youth soccer players are specializing earlier and committing to play college soccer at a younger age compared with when current college and professional players did.

Limb dominance influences energy absorption contribution (EAC) during landing after anterior cruciate ligament reconstruction

OBJECTIVE

To determine the role of limb dominance on energy absorption contribution (EAC) during a jump landing (JL) task at return to sport (RTS) after ACL-R.

DESIGN

Cross-sectional study.

SETTING

Clinical Research Laboratory.

PARTICIPANTS

One hundred eight participants (age = 16.19 ± 1.74, Height = 172.25 ± 9.96 cm, Weight = 72.61 ± 15.48 kg).

MAIN OUTCOME MEASURES

Participants were grouped into two groups: those who injured their dominant limb ACL (D-ACL) and those who injured their non-dominant limb ACL (ND-ACL). A multiple analysis of variance (MANOVA) was used to assess for between group differences in EAC across the three joints.

RESULTS

In the surgical limb, D-ACL demonstrated smaller hip (D-ACL = 32.23 ± 10.44%, ND-ACL = 69.68 ± 8.51%, p < 0.008) and greater knee (D-ACL = 45.86 ± 10.36%, ND-ACL = 9.41 ± 5.68%, p < 0.008) EAC than ND-ACL. In the non-surgical limb, D-ACL demonstrated greater hip (D-ACL = 62.59 ± 9.03%, ND-ACL = 25.95 ± 7.15%, p < 0.008), and smaller knee (D-ACL = 13.79 ± 5.57%, ND-ACL = 58.01 ± 7.86%, p < 0.008), EAC than ND-ACL.

CONCLUSION

After ACL-R, eccentric loading strategies during a JL task at RTS are different depending upon limb dominance. D-ACL demonstrated a greater knee loading strategy on the surgical side compared to ND-ACL.

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

ABSTRACT

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

Differences in Lower Extremity Movement Quality by Level of Sport Specialization in Cadets Entering a United States Service Academy

BACKGROUND

Sport specialization in youth athletes is associated with increased risk for musculoskeletal injury; however, little is known about whether sport specialization is associated with lower extremity movement quality. The purpose of this study was to examine differences in lower extremity movement quality by level of sport specialization in US Service Academy cadets.

HYPOTHESIS

Cadets who report an increased level of sport specialization would have a lower level of movement quality than those who are less specialized.

STUDY DESIGN

Cross-sectional analysis from an ongoing prospective cohort study.

LEVEL OF EVIDENCE

Level 3.

METHODS

Cadets completed the Landing Error Scoring System (LESS) and a baseline questionnaire evaluating level of sport specialization during high school. Data were analyzed using separate 1-way analysis of variance models.

RESULTS

Among all participants (n = 1950), 1045 (53.6%) reported low sport specialization, 600 (30.8%) reported moderate sport specialization, and 305 (15.6%) reported high sport specialization at the time of data collection during the first week. Ages ranged from 17 to 23 years. Men (1491) and women (459) reported comparable specialization levels (P = 0.45). There were no statistically significant differences in lower extremity movement quality by level of specialization for all subjects combined (P = 0.15) or when only men were included in the analyses (P = 0.69). However, there were statistically significant differences in movement quality by level of specialization in women (P = 0.02). Moderately specialized women had the best movement quality (mean, 4.63; SD, 2.21) followed by those with high specialization (mean, 4.90; SD, 2.08) and those with low levels of specialization (mean, 5.23; SD, 2.07).

CONCLUSION

Women reporting moderate sport specialization had improved movement quality and significantly better LESS scores compared to those with high/low specialization.

CLINICAL RELEVANCE

Athletes, especially women, should be encouraged to avoid early sport specialization to optimize movement quality, which may affect injury risk.

What Defines Early Specialization: A Systematic Review of Literature

Introduction: While practitioners and organizations advise against early specialization, the lack of a consistent and clear definition of early specialization reduces the impact of recommendations and policies in youth sport. An important first step in understanding the consequences of early specialization is establishing what early specialization is. Objectives: This PRISMA-guided systematic review aimed to determine the types, characteristics, and general content of early specialization papers within the literature, and examine how early specialization has been defined and measured in order to advance knowledge toward a clear and consistent definition of early specialization. Data sources: Four different electronic databases were searched (SPORTDiscus, Web of Science, Sports Medicine and Education Index, and Scopus). Both non data-driven and data-driven studies were included to ensure a comprehensive understanding of the literature. Eligibility Criteria: In order to be included in the review, the paper must: (a) Focus on specialization and explicitly use the term "specialization" (b) Focus on sport and athletes (c) Be papers from a peer-reviewed (d) Be in English. And finally, (e) be available in full text. Results: One thousand three hundred and seventy one articles were screened resulting in 129 articles included in the review after applying inclusion/exclusion criteria. Results indicated a clear discrepancy between key components of early specialization and the approaches used to classify early specializers. Conclusion: Future research should work toward developing a valid and reliable approach to classifying early specializers and establishing a consistent definition across studies.

Factors influencing the Landing Error Scoring System: Systematic review with meta-analysis

OBJECTIVES

Systematically review the literature addressing age, sex, previous injury, and intervention program as influencing factors of the Landing Error Scoring System.

DESIGN

Systematic review with meta-analysis.

METHODS

Three databases (PubMed, Web of Science®, and Scopus®) were searched on 1 April 2020. Original studies using the Landing Error Scoring System as primary outcome and exploring age, sex, previous injury, and intervention program were included, assessed for risk of bias, and critically appraised. Three meta-analyses were performed using one random and two mixed effect models with dependent variables: sex, previous injury and intervention program, respectively. Grading of Recommendations Assessment, Development and Evaluation was used to evaluate the strength of the evidence. PROSPERO registration number CRD42018107210.

RESULTS

Fifty-two studies were included. Pooled data indicated that females have higher Landing Error Scoring System scores than males (p<0.001, mean difference=0.6 error). Participants with previous anterior cruciate ligament injury have higher LESS scores than healthy controls (p=0.004, mean difference 1.2 error). Neuromuscular training programs lasting a minimum of six weeks and other intervention programs decrease Landing Error Scoring System scores (p<0.001, mean difference 1.2 error and p=0.042, mean difference 0.5 error, respectively). There is limited evidence suggesting that age may influence Landing Error Scoring System scores in clinically meaningful manner. Overall, Grading of Recommendations Assessment, Development and Evaluation ratings suggest very low strength of evidence.

CONCLUSIONS

History of anterior cruciate ligament injury and undertaking neuromuscular training for a minimum of six weeks meaningfully altered Landing Error Scoring System scores. These findings, however, should be interpreted cautiously considering the very low Grading of Recommendations Assessment, Development and Evaluation rating of the evidence.

The Concept of Sport Sampling Versus Sport Specialization: Preventing Youth Athlete Injury: A Systematic Review and Meta-analysis

BACKGROUND

The prevalence of youth athletes specializing in 1 sport has been increasing over the past decade. Subsequently, the rate of youth athlete injury has also been increasing. It is possible that an association exists between youth specialization and sports injury rate.

PURPOSE

To determine if sport sampling is associated with a lower sports injury rate in youths compared with youths who specialize in 1 sport.

STUDY DESIGN

Systematic review and meta-analysis.

METHODS

A systematic review was conducted following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines using PubMed, Embase, and the Cochrane library. Inclusion criteria included studies written in the English language, studies with athletes between 7 and 18 years of age, studies that report injury rates, and studies that specify if athletes were sport samplers or specialized in a sport. Data relevant to this study, including injuries and patient characteristics, were extracted and statistically analyzed.

RESULTS

The initial search identified 324 studies, 6 of which met inclusion criteria. From these 6 studies, the total participant number was 5736. Of those, 2451 (42.7%) were "sport samplers," 1628 (28.4%) were "sport specializers," and 1657 (28.9%) were considered "others" (ie, could not be classified as true samplers or true specializers). The average age of all the athletes was 14.6 years (range, 7-18 years). Sport specializers had a significantly higher injury risk than the sport samplers (RR, 1.37; 95% CI, 1.19-1.57; P < .0001). There was a higher risk of injury in the "others" group when compared with the "sport sampler" group (RR, 1.21; 95% CI, 1.14-1.29; P < .0001). There was a higher risk of injury in the "sport specializer" group over the "others" group (RR, 1.09; 95% CI, 1.04-1.14; P < .005).

CONCLUSION

Sport sampling is associated with a decreased risk of sports injury in youth athletes when compared with those who specialize in 1 sport. Injury rates increase as a youth athlete becomes increasingly specialized. Youth athletes would benefit substantially from participating in sport sampling.

Single Sport Specialization in the Skeletally Immature Athlete: Current Concepts

Youth sport participation patterns have drastically changed over the past two decades. Increasingly, young individuals are specializing in single sport while skeletally immature. Sport specialization in the growing athlete has profound effects on performance, short- and long-term injury risks, and joint health. Evidence continues to mount as the detrimental effects of this trend on the immature athlete. The knee, shoulder, and elbow of these young athletes are particularly affected by this emphasis on skill-based sporting activity as opposed to generalized fitness and participation. An understanding of the epidemiology of sport participation, particularly financial impacts, and the effects on elite sport performance are critical so that the clinician can effectively educate athletes, parents, and coaches.

An Index Approach to Early Specialization Measurement: An Exploratory Study

The methodological underpinnings of studies into early specialization have recently been critiqued. Previous researchers have commented on the variety of, and over-simplified, methods used to capture early specialization. This exploratory study, therefore, suggests a new direction for how early specialization can be conceptualized and measured. We aim to create an index approach whereby early specialization is measured as a continuous variable, in line with commonly used definitions. The continuous variable for degrees of early specialization is calculated from a questionnaire which captures the four key components of early specialization; (1) intensity, (2) year-round training, (3) single sport, and (4) commencing age 12 or younger. The proposed index approach is illustrated in a sample of 290 Swedish aesthetic performers aged 12-20 years (M = 15.88), whose descriptive statistics are used to discuss the suitability and usability of the measure. The proposed index approach functions as a guideline to future researchers. We hope that introducing a new index approach we will encourage further discussion around the measurement of early specialization. Additionally, we hope to pave the way for future research to explore more complex research questions.

Clinical implications of Landing Error Scoring System calculation methods

OBJECTIVES

To explore whether final Landing Error Scoring System (LESS) scores differ between calculation methods used in literature.

DESIGN

Cross-sectional.

SETTING

Laboratory.

PARTICIPANTS

328 individuals.

MAIN OUTCOME MEASURES

LESS scores from 984 drop-jumps were extracted. Final LESS scores were calculated for every participant according to five methods: mean of 3 jumps, 1st jump score, 3rd jump score, best jump score, and sum of errors present in at least 2 jumps. The influence of the calculation method on group mean LESS score and group-level risk categorization using threshold of 5 errors was estimated using Generalized Estimating Equations, with the mean of 3 jumps score set as the reference method. The agreement in individual-level risk categorization was assessed using odds ratios and McNemar's tests.

RESULTS

Compared to the reference, estimated group mean LESS score was 0.92 errors lower (p < 0.001) using the best jump method, as was group-level risk categorization (odds ratio: 0.50, p < 0.001). Individual-level risk categorization between calculation methods was inconsistent for 8-15% of participants compared to the reference method, significantly different from reference for the best jump score method (p < 0.001).

CONCLUSIONS

Calculation method meaningfully influences final LESS scores and risk categorization.

Is the Landing Error Scoring System Reliable and Valid? A Systematic Review

CONTEXT

The Landing Error Scoring System (LESS) is a clinical tool often used in research and practice to identify athletes presenting high injury-risk biomechanical patterns during a jump-landing task.

OBJECTIVE

To systematically review the literature addressing the psychometric properties of the LESS.

DATA SOURCES

Three electronic databases (PubMed, Web of Science, and Scopus) were searched on March 28, 2018, using the term "Landing Error Scoring System."

STUDY SELECTION

All studies using the LESS as main outcome measure and addressing its reliability, validity against motion capture system, and predictive validity were included. Original English-language studies published in peer-reviewed journals were reviewed. Studies using modified versions of the LESS were excluded.

STUDY DESIGN

Systematic literature review.

LEVEL OF EVIDENCE

Level 4.

DATA EXTRACTION

Study design, population, LESS testing procedures, LESS scores, statistical analysis, and main results were extracted from studies using a standardized template.

RESULTS

Ten studies met inclusion criteria and were appraised using Newcastle-Ottawa Quality Assessment Scale adapted for cross-sectional studies. The overall LESS score demonstrated good-to-excellent intrarater (intraclass correlation coefficient [ICC], 0.82-0.99), interrater (ICC, 0.83-0.92), and intersession reliability (ICC, 0.81). The validity of the overall LESS score against 3-dimensional jump-landing biomechanics was good when individuals were divided into 4 quartiles based on LESS scores. The validity of individual LESS items versus 3-dimensional motion capture data was moderate-to-excellent for most of the items addressing key risk factors for anterior cruciate ligament (ACL) injury. The predictive value of the LESS for ACL and other noncontact lower-extremity injuries remains uncertain based on the current scientific evidence.

CONCLUSION

The LESS is a reliable screening tool. However, further work is needed to improve the LESS validity against motion capture system and confirm its predictive validity for ACL and other noncontact lower-extremity injuries.

Previous High School Participation in Varsity Sport and Jump-Landing Biomechanics in Adult Recreational Athletes

CONTEXT

Early sports sampling is associated with superior biomechanics in youth athletes; however, the effect of multisport participation on adult biomechanics is unknown.

OBJECTIVE

To compare jump-landing biomechanics between adult recreational athletes who previously participated in 0, 1, or 2 or more select high school varsity sports (VSs; basketball, lacrosse, soccer, volleyball) that feature landing and cutting tasks.

DESIGN

Descriptive laboratory study.

SETTING

University community setting.

PATIENTS OR OTHER PARTICIPANTS

Fifty adult recreational athletes (22 women, 28 men; age = 23.8 ± 2.5 years) with no high school VS experience or with high school VS experience in basketball, lacrosse, soccer, or volleyball. Athletes were grouped into those who participated in 0 (0VS, n = 11), 1 (1VS, n = 21), or 2 or more (2VSs, n = 18) of these sports at the high school level.

MAIN OUTCOME MEASURE(S)

The average Landing Error Scoring System (LESS) total score from 3 individual jump landings was determined. A 1-way analysis of covariance using sex as the covariate was calculated to compare groups. The Pearson R was used to test for the correlation between the LESS score and number of sports played, and a linear regression analysis was performed using the number of sports played to predict the LESS score. The α level was set a priori at .05.

RESULTS

The 0VS athletes produced similar LESS scores as the 1VS athletes (5.89 ± 1.2 versus 5.38 ± 1.93 points, respectively, P = .463), whereas the 2VSs athletes demonstrated lower LESS scores (3.56 ± 1.97 points) than the 0VS (P = .002) and 1VS (P = .004) athletes. The LESS scores were moderately negatively correlated with the number of high school VSs played (R² = -0.491, P < .001). The linear regression analysis was significant (F_1,37 = 9.416, P = .004) with R² = 0.203. For every additional VS played at the high school level, the LESS score decreased by 1.28 points.

CONCLUSIONS

Landing Error Scoring System scores were lower in athletes who had a history of multisport high school varsity participation in basketball, lacrosse, soccer, or volleyball compared with those who had a history of single-sport or no participation in these sports at this level. Multisport high school varsity participation in these sports may result in improved neuromuscular performance and potentially reduced injury risks as adults.

Sport Specialization and Fitness and Functional Task Performance Among Youth Competitive Gymnasts

CONTEXT

Gymnastics trains fundamental movement skills but has high rates of early sport specialization. Early specialization is associated with increased injury risk. Gymnasts devote time to developing technical skill, but whether specialization status influences performance is unknown.

OBJECTIVE

To describe the participation and specialization characteristics of youth club gymnastics participants and determine whether the level of specialization is associated with fitness and functional task performance.

DESIGN

Retrospective cross-sectional study.

SETTING

A single gymnastics facility.

PATIENTS OR OTHER PARTICIPANTS

Data on youth gymnasts (n = 131; 84 females, 47 males; age = 10.9 ± 2.9 years, height = 142.14 ± 16.23 cm, mass = 38.15 ± 12.93 kg) were reviewed.

MAIN OUTCOME MEASURE(S)

Specialization was assessed using a 3-tiered classification. Fitness measurements consisted of the Gymnastics Functional Measurement Tool, Men's Gymnastics Functional Measurement Tool, and core strength. Functional tasks evaluated hop performance, dynamic balance, and jump-landing technique. Separate analyses of covariance, covaried by age, hours of training, and years of gymnastics participation, were used to identify differences in fitness and functional performance among specialization groups. Pearson product correlations were calculated to evaluate the relationships between training hours per week and years in gymnastics with fitness and functional performance.

RESULTS

Most gymnasts were classified as moderately (50.4%, n = 66) or highly (35.1%, n = 46) specialized. Only 14.5% (n = 19) were classified as having a low level of specialization. Weak to moderate correlations were present between years in gymnastics and most fitness tasks. Moderate to strong correlations were noted between training hours per week and most fitness tasks. Low-specialization gymnasts scored lower on right lower extremity Y-balance (P = .004), upper left extremity Y-balance (P = .033), and right hop performance (P = .039) tests.

CONCLUSIONS

Gymnasts reported high proportions of moderate to high specialization, and many exceeded guidelines for hours participating in gymnastics per week. We did not observe clinically meaningful group differences among specialization status and fitness or functional movement tasks, indicating no clear benefit of gymnastics training to the exclusion of other sports for increased performance.

The Public Health Consequences of Sport Specialization

Sport specialization was thought to affect a relatively small number of elite athletes, but it is now a common practice in youth sport culture. Recent research in the field of sport specialization has led to a better understanding of the influence this issue is having on youth (ie, younger than 19 years of age) today. This review focuses on sport specialization from a public health perspective to elucidate the effect that this practice is having within the United States. The specific goals of this review are to describe (1) the prevalence of sport specialization and the factors that may affect the decision to specialize, (2) the costs of youth sport-related injuries in the context of sport specialization, (3) the financial costs that sport specialization has for families, and (4) how sport specialization may be affecting physical literacy.

Eccentric Resistance Training in Youth: Perspectives for Long-Term Athletic Development

The purpose of this narrative review is to discuss the role of eccentric resistance training in youth and how this training modality can be utilized within long-term physical development. Current literature on responses to eccentric exercise in youth has demonstrated that potential concerns, such as fatigue and muscle damage, compared to adults are not supported. Considering the importance of resistance training for youth athletes and the benefits of eccentric training in enhancing strength, power, speed, and resistance to injury, its inclusion throughout youth may be warranted. In this review we provide a brief overview of the physiological responses to exercise in youth with specific reference to the different responses to eccentric resistance training between children, adolescents, and adults. Thereafter, we discuss the importance of ensuring that force absorption qualities are trained throughout youth and how these may be influenced by growth and maturation. In particular, we propose practical methods on how eccentric resistance training methods can be implemented in youth via the inclusion of efficient landing mechanics, eccentric hamstrings strengthening and flywheel inertia training. This article proposes that the use of eccentric resistance training in youth should be considered a necessity to help develop both physical qualities that underpin sporting performance, as well as reducing injury risk. However, as with any other training modality implemented within youth, careful consideration should be given in accordance with an individual's maturity status, training history and technical competency as well as being underpinned by current long-term physical development guidelines.

Impact of youth sports specialisation on career and task-specific athletic performance: a systematic review following the American Medical Society for Sports Medicine (AMSSM) Collaborative Research Network’s 2019 Youth Early Sport Specialisation Summit

Objective

The impact, positive or negative, of youth sport specialisation (YSS) on short-term and long-term performance is not fully understood; however, the desire to maximise performance goals is generally considered the primary reason children and adolescents specialise at a young age. We performed a systematic review of original research to establish the association of YSS and task-focused or career-focused performance outcomes.

Design

Systematic review.

Data sources

Databases searched include PubMed, EMBASE, Cochrane, CINAHL and SPORTDiscus.

Eligibility criteria

We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to identify peer-reviewed research articles published in English between 1 January 1990 and 31 December 2018 that reported original findings on the association of YSS and performance outcomes. Studies without an explicit measure of sport specialisation, for example, volume measures without measuring sport specialisation, were excluded.

Results

Twenty-two articles were included in the final review; 15 addressed career performance outcomes and 7 considered task performance outcomes. All identified studies were cross-sectional or retrospective in design. The proportion of elite athletes who specialised early ranged between 7% and 85%, depending on sport and definition of specialisation. Elite athletes often specialised between the ages of 14 and 15 compared with their non-elite or semi-elite peers who typically specialised prior to 13 years. In addition, neuromuscular control, anterior reach asymmetry and physical task outcomes did not differ by specialisation status.

Conclusion

The volume and methodological rigour of published research in this field are limited. Our review suggests that YSS is not required to achieve success at elite levels. YSS also does not appear to improve task-related performance (eg, anterior reach, neuromuscular control) outcomes for specialised athletes when compared with non-specialised athletes during childhood and adolescence.

Youth Sports Specialization: Does Practice Make Perfect?

In the United States, there has been a steady increase in sports participation across all age groups. An estimated 27 million youths between the ages of 6 and 18 years participate in team sports, and 60 million participate in some form of organized athletics. While there are great benefits from sports participation, early single sport specialization carries an increased risk of overuse injuries and burnout. Specialization has become increasingly popular among parents and coaches due to the common belief that it is the best way to develop an elite athlete. However, for most sports, there is no evidence that specialization before puberty is necessary to achieve elite status and in fact, there is evidence to the contrary. A recent American Orthopaedic Society for Sports Medicine (AOSSM) consensus statement has highlighted the negative side effects of early sports specialization; these include increased risk for overuse injury and burnout. School nurses are well-positioned to affect this issue through providing education and raising awareness of the potential detrimental consequences associated with youth sport specialization.

Tracking of sport and exercise types from midlife to old age: a 20-year cohort study of British men

Background

Previous physical activity (PA) tracking studies have examined the stability of overall PA and/or PA types, but few have investigated how specific types of sport/exercise track over the life course. The aim of this study was to determine how specific sports/exercises in midlife track and predict future sport/exercise and PA in men transitioning to old age.

Methods

Seven thousand seven hundred thirty-five men (aged 40–59 years) recruited in 1978–80 were followed up after 12, 16 and 20 years. At each wave men self-reported participation in sport/exercise. Frequent sport/exercise participants (> 1/month) reported the types of sport/exercise they engaged in. Men also reported total PA, health status, lifestyle behaviours and socio-demographic characteristics. Stability of each sport/exercise was assessed using kappa statistics and intraclass correlation coefficients. Logistic regression estimated the odds of participating in sport/exercise and being active at 20-year follow up according to specific types of sport/exercise in midlife.

Results

Three thousand three hundred eighty-four men with complete data at all waves were included in analyses. Tracking of specific sports/exercises ranged from fair to substantial, with golf being the most common and most stable. Bowls was the most frequently adopted. Odds of participating in sport/exercise and being active in old age varied according to sport/exercise types in midlife. Golf and bowls in midlife were the strongest predictors of sport/exercise participation in old age. Golf, cricket and running/jogging in midlife were among the strongest predictors of being active in old age. Compared to participating in just one sport/exercise in midlife, sampling multiple sports/exercises was more strongly associated with sport/exercise participation and being active in old age.

Conclusion

The stability of sport/exercise participation from midlife to old age varies by type. Specific sports/exercises in midlife may be more likely to predict future PA than others. However, participating in a range of sports/exercises may be optimal for preserving PA into old age.

Electronic supplementary material

The online version of this article (10.1186/s11556-018-0205-y) contains supplementary material, which is available to authorized users.