Youth soccer players: patterns of injury involving the primary growth plates of epiphyses.

Youth soccer (football) is immensely popular internationally. Earlier participation, sport sub-specialization, and year-around practice have led to an increased incidence of injury from both acute trauma and repetitive overuse. The growth plates (physes) of the immature skeleton are particularly vulnerable to injury and delayed diagnosis can lead to future growth disturbance and long-term morbidity. Familiarity with the various components of the growth plate complex necessary for ensuring normal endochondral ossification is fundamental in understanding the various patterns of imaging findings following injury. This review discusses the zonal columnar arrangement of the growth plate proper and the contrasting function of the vasculature within the subjacent epiphysis and metaphysis. This is followed by an evidence-based discussion of the common patterns of injury involving the epiphyseal primary growth plate observed among youth soccer players: subcategorized into physeal fractures (direct injury) and physeal stress injuries (indirect insult to subjacent metaphysis). In this section, the role of imaging and characteristic imaging features will be discussed. While the normal physiologic and pathophysiologic mechanisms can be applied to other growth plates, such as primary growth plates underlying the apophyses and secondary growth plates surrounding the secondary ossificiation centers, which also undergo endochondral ossification, the current review is focused on injuries involving the primary growth plates underlying epiphyses.

Metabolic Rate in Adolescent Athletes: The Development and Validation of New Equations, and Comparison to Previous Models.

We sought to assess the accuracy of current or developing new prediction equations for resting metabolic rate (RMR) in adolescent athletes. RMR was assessed via indirect calorimetry, alongside known predictors (body composition via dual-energy X-ray absorptiometry, height, age, and sex) and hypothesized predictors (race and maturation status assessed via years to peak height velocity), in a diverse cohort of adolescent athletes (n = 126, 77% male, body mass = 72.8 ± 16.6 kg, height = 176.2 ± 10.5 cm, age = 16.5 ± 1.4 years). Predictive equations were produced and cross-validated using repeated k-fold cross-validation by stepwise multiple linear regression (10 folds, 100 repeats). Performance of the developed equations was compared with several published equations. Seven of the eight published equations examined performed poorly, underestimating RMR in >75% to >90% of cases. Root mean square error of the six equations ranged from 176 to 373, mean absolute error ranged from 115 to 373 kcal, and mean absolute error SD ranged from 103 to 185 kcal. Only the Schofield equation performed reasonably well, underestimating RMR in 51% of cases. A one- and two-compartment model were developed, both r2 of .83, root mean square error of 147, and mean absolute error of 114 ± 26 and 117 ± 25 kcal for the one- and two-compartment model, respectively. Based on the models' performance, as well as visual inspection of residual plots, the following model predicts RMR in adolescent athletes with better precision than previous models; RMR = 11.1 × body mass (kg) + 8.4 × height (cm) - (340 male or 537 female).

The Temporal Ordering of Motivation and Self-Control: A Cross-Lagged Effects Model.

Mechanisms leading to cognitive energy depletion in performance settings such as high-level sports highlight likely associations between individuals' self-control capacity and their motivation. Investigating the temporal ordering of these concepts combining self-determination theory and psychosocial self-control theories, the authors hypothesized that athletes' self-control capacity would be more influenced by their motivation than vice versa and that autonomous and controlled types of motivation would predict self-control capacity positively and negatively, respectively. High-level winter-sport athletes from Norwegian elite sport colleges (N = 321; 16-20 years) consented to participate. Using Bayesian structural equation modeling and 3-wave analyses, findings revealed credible self-control → motivation → self-control cross-lagged effects. Athletes' trait self-control especially initiated the temporal ordering of the least controlled types of motivation (i.e., intrinsic, integrated, and amotivation). Findings indicate that practicing self-control competencies and promoting athletes' autonomous types of motivation are important components in the development toward the elite level. These components will help athletes maintain their persistent goal striving by increasing the value and inherent satisfaction of the development process, avoiding the debilitating effects of self-control depletion and exhaustion.

Sagittal Spinal Morphotype Assessment in Dressage and Show Jumping Riders.

CONTEXT: Previous research has analyzed how the sport influences sagittal spinal curvatures in young athletes and has found that spinal curves may be modified as a consequence of repeated movement patterns and postures of each discipline. OBJECTIVE: To analyze sagittal spinal alignment by equestrian discipline and its relation to training load, and to describe "sagittal integrative morphotype" in young riders. DESIGN: Observational descriptive study. SETTING: Training room. PARTICIPANTS: A total of 23 riders (aged 9-17 y)-13 dressage riders (3 males and 10 females) and 10 show jumping riders (5 males and 5 females)-participated voluntarily. MAIN OUTCOME MEASURES: Mann-Whitney U test was applied to determine differences between riders' characteristics (gender, discipline, and training load) and spine variables. RESULTS: According to normality ranges for spinal curves, females showed an increase for lumbar curvature in standing position. It was found that show jumping riders manifested an increment in thoracic and lumbar curves while standing and an increase in the thoracic curvature in slump sitting. Statistically significant differences were found when lumbar curvature, "sit and reach" distance, and lumbo-horizontal angle in flexion were analyzed by gender in "sit and reach" test. No statistical significant differences were found when spinal curves in each position were analyzed depending on the training load. With regard to "sagittal integrative morphotype," all riders presented a hyperkyphotic dorsal morphotype no matter what their discipline. As for the lumbar curve, dressage and show jumping riders presented a functional hyperkyphotic morphotype. CONCLUSIONS: It is important to note that many riders presented a sagittal imbalance for the thoracic and lumbar curves. Therefore, as the sagittal spinal misalignments persist and worsen over time, exercise programs to prevent or rehabilitate these imbalances in young riders will be needed. The "sagittal integrative morphotype" assessment is an essential tool in order to identify the spinal misalignment.

Age and maturity related differences in motor coordination among male elite youth soccer players.

This study investigated differences in generic and soccer specific motor coordination, as well as speed and agility depending on age and maturity in elite youth soccer players (U10-U15, N = 619). Measurements included body height, body weight and sitting height to estimate age at peak height velocity (APHV); three Körperkoordinationstest für Kinder subtests (i.e. jumping sideways (JS), moving sideways (MS), balancing backwards (BB)) to assess generic motor coordination; the UGent dribbling test for soccer specific motor coordination; a 5m/30m sprint and T-test for speed and agility, respectively. Age specific z-scores of the predicted APHV identified players as earlier, on time or later maturing. (M)ANOVA analyses showed significant age by maturity interaction effects for the speed and agility test cluster, revealing maturity related differences in U14 and U15 players. Next to an overall higher performance with age for all test clusters (η2 0.080-0.468), earlier maturing players outperformed their later maturing peers in 5m/30m sprinting. The opposite was seen for JS and BB. So, players' maturity status should be taken into account to adequately value performance in talent identification. Also, the focus on characteristics that appear to be minimally biased by an earlier maturational timing (i.e. motor coordination) should be increased.

Incidence and risk factors for back pain in young floorball and basketball players: A Prospective study.

The aim of this study was to investigate the incidence of back pain in young basketball and floorball players under 21 years of age. The secondary aim was to examine risk factors especially for low back pain (LBP). Nine basketball and nine floorball teams (n = 396) participated in this prospective follow-up study (2011-2014). Young athletes (mean age 15.8 ± 1.9) performed physical tests and completed a questionnaire at baseline. The follow-up lasted 1-3 years per player. During the follow-up, back pain reported by the players was registered on a weekly basis and verified by a study physician. The exposure time (AE) on team practices and games was recorded by the coach. Altogether back pain was reported 61 times by 51 players. The incidence of back pain was 87 per 1000 athlete-years and 0.4 per 1000 hours of AE. Hamstrings, quadriceps and iliopsoas extensibility and general joint hypermobility were not associated with LBP. Furthermore, no association between LBP and leg extension strength or isometric hip abduction strength asymmetry was found in these young basketball and floorball players. In conclusion, back pain can lead to a considerable time-loss from training and competition among young basketball and floorball players and the pain tends to reoccur. Lower extremity muscle extensibility, general joint hypermobility or investigated lower extremity strength measures were not associated with the risk of LBP.

Game and Training Load Differences in Elite Junior Australian Football.

Game demands and training practices within team sports such as Australian football (AF) have changed considerably over recent decades, including the requirement of coaching staff to effectively control, manipulate and monitor training and competition loads. The purpose of this investigation was to assess the differences in external and internal physical load measures between game and training in elite junior AF. Twenty five male, adolescent players (mean ±SD: age 17.6 ± 0.5 y) recruited from three elite under 18 AF clubs participated. Global positioning system (GPS), heart rate (HR) and rating of perceived exertion (RPE) data were obtained from 32 game files during four games, and 84 training files during 19 training sessions. Matched-pairs statistics along with Cohen's d effect size and percent difference were used to compare game and training events. Players were exposed to a higher physical load in the game environment, for both external (GPS) and internal (HR, Session-RPE) load parameters, compared to in-season training. Session time (d = 1.23; percent difference = 31.4% (95% confidence intervals = 17.4 - 45.4)), total distance (3.5; 63.5% (17.4 - 45.4)), distance per minute (1.93; 33.0% (25.8 - 40.1)), high speed distance (2.24; 77.3% (60.3 - 94.2)), number of sprints (0.94; 43.6% (18.9 - 68.6)), mean HR (1.83; 14.3% (10.5 - 18.1)), minutes spent above 80% of predicted HRmax (2.65; 103.7% (89.9 - 117.6)) and Session-RPE (1.22; 48.1% (22.1 - 74.1)) were all higher in competition compared to training. While training should not be expected to fully replicate competition, the observed differences suggest that monitoring of physical load in both environments is warranted to allow comparisons and evaluate whether training objectives are being met. Key pointsPhysical loads, including intensity, are typically lower in training compared to competition in junior elite Australian football.Monitoring of player loads in team sports should include both internal and external measures.Selected training drills should look to replicate game intensities, however training is unlikely to match the overall physical demands of competition.

Name, Image, and Likeness and the Health of the Young Athlete: A Call to Action for Sports Medicine Providers and the Athletic Healthcare Network.

CONTEXT: In June 2021, the National Collegiate Athletic Association (NCAA) adopted a new policy allowing NCAA athletes the opportunity to benefit and profit from their name, image, and likeness (NIL). Several state high-school associations have established policies to guide their members and students through the new era of NIL. While the potential benefits cannot be ignored, NIL presents novel responsibilities and stressors to athletes. This paper will review the paucity of literature on the effect of NIL on youth athletes and bring attention to mental health, well-being, or academic performance impacted by NIL. EVIDENCE ACQUISITION: Articles were identified through Google and PubMed search starting from NIL policy approval (June 30, 2021). Search terms included "name, image and likeness" and "NIL." STUDY DESIGN: Clinical commentary. LEVEL OF EVIDENCE: Level 5. RESULTS: Although 1 article was identified through PubMed search and numerous articles were identified through Google search, no articles directly evaluated the effects of NIL on the mental health, well-being, or academic performance of youth athletes. CONCLUSION: It is critical for sports medicine providers and other members of the athletic healthcare network to familiarize themselves with these emerging topics to best serve their patients and communities. The athletic healthcare network must be prepared to address possible NIL-related health ramifications for our patients and their families and help them navigate a confusing and predatory landscape. We must provide resources to youth athletes to minimize the risks associated with NIL involvement and related activities, and to ensure that athletes with NIL contracts are able to balance their academic and athletic responsibilities. Fostering strong relationships between stakeholders and sports medicine staff is paramount to creating an environment that permits honest discussions about NIL and the health of athletes from youth to adulthood. STRENGTH-OF-RECOMMENDATION TAXONOMY: N/A.

Differences in Lumbopelvic Alignment in Adolescent Male Soccer Players With Bilateral and Unilateral Lumbar Bone Stress Injuries: An MRI Evaluation.

Background: Differences in the physical characteristics of bilateral and unilateral lumbar bone stress injuries (BSIs) are unknown. Purpose: To compare bilateral and unilateral lumbar BSIs in adolescent male soccer players, with a focus on lumbopelvic alignment. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 78 players (age range, 12-15 years) from a local soccer club who had magnetic resonance imaging (MRI) evaluations were included in the study. Lumbopelvic alignment and lumbar BSI were evaluated using short-tau inversion recovery and 3-dimensional LAVA on 3-T MRI; lumbar BSI was defined as the presence of bone marrow edema and/or the complete and incomplete fracture in the pars region on the MRI. Pelvic tilt (PT) and pelvic outflare angles were assessed on the kicking and pivoting sides, and asymmetry for each parameter was calculated by subtracting the kicking side from the pivoting side. In addition, the lumbar lordosis (LL), sacral slope (SS), and SS relative to LL (calculated by subtracting LL from the SS) were assessed. One-way analysis of variance was performed to compare lumbopelvic alignment in players with bilateral BSI, unilateral BSI, or no abnormal findings (controls). Results: No significant differences were found regarding lumbopelvic alignment between the players with bilateral versus unilateral lumbar BSI. PT asymmetry was significantly greater in both players with bilateral lumbar BSI and unilateral lumbar BSI compared with controls (P = .018 and P = .016, respectively). In addition, SS relative to LL was significantly greater in players with bilateral lumbar BSI compared with controls (P < .001). Conclusion: Although there were no significant lumbopelvic alignment differences between bilateral and unilateral BSI, players with bilateral BSI exhibited increased sacral anterior tilt relative to the LL, and the pelvis was more posterior on the pivoting side than on the kicking side in both players with bilateral BSI and unilateral BSI. Our results suggest that lumbopelvic alignment assessment may contribute to the management strategy for players with lumbar BSI and to the identification of players at high risk of lumbar BSI.

Rehabilitation of Supraspinatus Impingement in a Volleyball Athlete: A Case Report.

Volleyball players with supraspinatus tendinopathy commonly present with a spectrum of symptoms, including shoulder pain, especially during the overhead phases of the game. They may experience pain during serves, spikes, or attempting to block at the net. Weakness in the affected shoulder and limited range of motion can impede performance and overall playing experience. Physiotherapy plays a crucial role in managing supraspinatus tendinopathy, focusing on reducing pain, improving shoulder joint range and function, and preventing recurrence. The research question arises as to how the rehabilitation process impacts the recovery and performance outcomes in a volleyball athlete with supraspinatus impingement which is explained as detailed in a case report. The present case is a 21-year-old male volleyball athlete complaining of pain in the anterolateral and posterior aspects of the right shoulder joint and a restricted range of motion while doing abduction and flexion at the shoulder joint for three months. After the orthopedic physical assessment, the patient was diagnosed with supraspinatus tendinopathy. This case report introduces an exact understanding of the rehabilitation tailored specifically to volleyball athletes with supraspinatus impingement.

Acute Anterior Thigh Compartment Syndrome in a Young Mixed Martial Arts Fighter.

Acute compartment syndrome (ACS) of the thigh is an uncommon injury, and diagnosis of such cases can be easily delayed or even missed due to the rare nature of this condition.  We present a case of ACS of the thigh in a young, healthy mixed martial arts (MMA) semi-professional athlete with no history of previous medical illnesses and normal coagulation.  This MMA fighter sustained a direct blow to the anterolateral aspect of his left thigh with a strong kick during a sparring match with his opponent.  After early surgical fasciotomy, this athlete returned to his pre-injury state and athletic performance within six to eight months postoperatively. Our literature review asserts that young athletic males with high muscle mass, engaging in contact sports, are at a higher risk of developing ACS of the thigh.

Injury and Treatment Characteristics of Middle School-Aged Patients Under the Care of Athletic Trainers from 2010-2022: A Report from the Athletic Training Practice-Based Research Network.

CONTEXT: Exploring sports-related musculoskeletal injuries and treatment characteristics in middle school sports may help inform patient care decisions such as appropriate medical coverage. OBJECTIVE: To describe injury and treatment characteristics of middle school-aged athletes receiving care from athletic trainers within the Athletic Training Practice-Based Research Network (AT-PBRN). DESIGN: Descriptive study. SETTING: Middle school. PATIENT OR OTHER PARTICIPANTS: Middle school-aged athletes (n=1,011; male=503, female=506) with sports-related musculoskeletal injuries. MAIN OUTCOME MEASURE(S): Electronic patient records were analyzed from the AT-PBRN from 59 athletic trainers across 14 states between 2010-2022. Summary statistics (frequency, percentages, median, interquartile ranges [IQR]) were used to describe injury (age at injury, sex, sport, body part, diagnosis) and treatment characteristics (type of treatment, number of visits, number of procedures per visit). RESULTS: Football (17.7%, n=179), basketball (17.6%, n=178), and soccer (14.9%, n=151) reported the highest number of injuries. Ankle (17.2%, n=174), knee (16.5%, n=167), and head (14.1%, n=143) were the most common injury locations. Concussion (13.0%, n=131), ankle strain/sprain (12.4%, n=125), and thigh/hip/groin sprain/strain (11.1%, n=112) were the most reported diagnoses. Therapeutic exercise or activities (25.6%, n=1068), athletic trainer evaluation or re-evaluation (22.9%, n=957) and hot/cold packs (18.4%, n=766) were the most common services with a median of 2 visits (IQR=1-4) and 2 procedures (IQR=1-2) per visit. CONCLUSIONS: Football, basketball, and soccer reported the most musculoskeletal injuries for middle school-aged athletes. Concussions were the most frequent diagnosis, followed by ankle sprains/strains. Our findings are similar to prior investigations at high school and collegiate levels. Treatments at the middle school level were also similar to those that have been previously reported at the high school level with therapeutic exercise/activity, athletic trainer evaluation or re-evaluation, and hot/cold packs being the most common treatments. This information may be useful for informing patient care decisions at the middle-school level.

Agreement between parent reported and child self-reported sport-related concussion history: A brief report.

This cross sectional investigation measured the agreement between parent report of their 8-14 year old child's sport-related concussion (SRC) history and their child's self-report of their own SRC history. Parent-child dyads (n = 405) within a youth contact sports (e.g., football, ice hockey, lacrosse, soccer) setting participated in the study. Parents (6.2%) and 8.6% of children self-reported a history of at least one diagnosed SRC. We observed substantial agreement between the number of parent-reported and child self-reported SRCs (κ = 0.613, p ≤ .001). Partial agreement regarding the number of SRCs reported by both groups was also substantial (weighted κ = 0.693, p ≤ .001). Removing dyads where neither the parent nor the child reported a diagnosed SRC, sensitivity analyses revealed only fair agreement in parent-child SRC recall. These results indicate that parents and youth athletes overall accounts of their diagnosed SRC history correspond. However determining specifics (e.g., total concussion counts) may benefit from concurrent parent reports, or documented events in medical histories.

Prevalence of Shoulder and Elbow Overuse Injuries Among Competitive Overhead Youth Athletes in Singapore.

Background: There is a dearth of information related to shoulder and elbow overuse injuries in Asian overhead youth athletes. Purpose: To determine the prevalence and severity of shoulder and elbow overuse injuries, as well as their associated factors, among competitive overhead youth athletes in Singapore. Study Design: Descriptive epidemiology study. Methods: Participants completed a survey consisting of 4 multiple-choice questions and 1 open-ended question. Data on sex, age, playing experience, and weekly training hours were also collected. Separate injury severity scores (range, 0-100, with higher scores indicating greater severity) for the shoulder and elbow were tabulated from the responses to the multiple-choice questions. The association between participant characteristics and presence of shoulder and elbow overuse injuries was determined using the chi-square test. Crude odds ratios (ORs) and 95% CIs were also calculated. Results: 532 overhead youth athletes (age, 12-18 years) responded, of which 434 responses were included for analysis. Badminton, cricket, softball, swimming, and volleyball were some of the sports studied. The prevalence of shoulder and elbow overuse injuries was 31.3% and 9.2%, respectively. The respective severity scores were 30.4 ± 14.4 and 38.4 ± 22.4. Age was associated with the presence of both shoulder (P = .016) and elbow (P = .037) overuse injuries. Years of experience was associated with the presence of substantial elbow injuries (P = .049). Weekly training hours was associated with the presence of shoulder (P = .016) and substantial shoulder (P = .020) injuries. Being older (15-18 years) increased the odds of shoulder (OR, 1.65; 95% CI, 1.10-2.49) and elbow (OR, 2.04; 95% CI, 1.03-4.01) overuse injuries. Having >8 years of experience increased the odds of substantial shoulder (OR, 2.71; 95% CI, 1.01-7.29) and substantial elbow (OR, 3.92; 95% CI, 1.01-15.24) overuse injuries. Training >11 hours per week increased the odds of shoulder overuse injuries (OR, 2.64; 95% CI, 1.31-5.30). Conclusion: Shoulder overuse injuries were more prevalent, but elbow injuries tended to be of greater severity among competitive overhead youth athletes in Singapore. Coaches working with older and experienced youth athletes, especially those training >11 hours per week, should be cognizant of the risk of shoulder and elbow overuse injuries.

Longitudinal changes in youth baseball batting based on body rotation and separation.

BACKGROUND: Identifying the characteristics of batting mechanics, such as the proper angle and position of each body segment in youth baseball players, is important for proper instructions. This study aimed to identify the age-related changes in batting kinematics including rotational and separational movements of the head, upper trunk, pelvis, and arms, in youth baseball players. METHODS: Over the three seasons, we measured the batting motion of baseball players aged 6- to 12 years using three high-speed cameras. Participants were divided into six age categories according to the little league eligibility rules (players were classified according to their age as of July 31 of a given year). Toss batting was performed using an automatic tossing machine set obliquely in front of the batter. Additionally, we analyzed the rotation angles of the head, upper trunk, pelvis, and arm direction, and the separation angles-calculated using the difference of each rotational angle and the head movement distance and step width-at five points in batting phase: stance, load, foot contact, pre-swing, and ball contact. Finally, 17 players from under 8 (U8, i.e., approximately 7-8 years) to U10 and 13 from U11 to U13 were analyzed. A one-way repeated measures analysis of variance was performed to analyze age-related changes in batting kinematics. RESULTS: Several age-related changes in batting kinematics at various batting point were observed. The head-to-upper trunk separation angle increased with age from U8 to U10 during the foot contact (effect sizes [ES] = 0.658) and from U11 to U13 during the pre-swing (ES = 0.630). Additionally, the U13 showed a significantly increase in the upper and pelvis separation angles during load, foot contact, and pre-swing compared with U11 and U12 (ES = 0.131, 0.793, and 0.480). CONCLUSION: Various changes in batting kinematics occurred among each age group. Notably, U12 and U13 had the greater upper trunk-to-pelvis separation angle at foot contact and pre-swing compared to U11. Therefore, it would be important for the instruction of younger baseball players to understand the underdevelopment of trunk separation when batting and encourage the acquisition of such separation movements.

Room for Improvement in Sports Nutrition Knowledge amongst Parents and Caregivers of Male Academy Soccer Players in the UK: A Cross-Sectional Study.

In professional soccer clubs in the UK, nutrition support is often polarised towards senior players or those in the senior academy age groups seeking first team selection/involvement. Accordingly, there is an increased reliance on parents and caregivers to provide support regarding nutritional intake. Therefore, the aim of this study was to evaluate the quality of nutrition knowledge of parents and caregivers of male youth soccer players within developmental academies in the UK. Across a single competitive season, 360 registered parents and caregivers of male soccer players from English Premier League under 9-11 (Foundation Phase) and under 12-16 (Youth Development Phase) age group academies completed an online version of the 88-item validated Nutrition for Sport Knowledge Questionnaire. Nutrition knowledge scores were classified as "poor" (43 ± 23%). Nutrition knowledge scores were significantly greater in respondents with dependents representing Category 1 (45 ± 13%) vs. Category 2 (39 ± 15%) academies and in Foundation Phase (44 ± 13%) vs. Youth Development Phase (41 ± 15%). These results demonstrate that there is room for improvement in the nutrition knowledge levels of parents and caregivers of male soccer academy players. We recommend that club academies provide appropriate resources towards nutritional education for parents and caregivers.

Validation of skinfold equations and alternative methods for the determination of fat-free mass in young athletes.

Intoduction: To cross-validate skinfold (SKF) equations, impedance devices, and air-displacement plethysmography (ADP) for the determination of fat-free mass (FFM). Methods: Male and female youth athletes were evaluated (n = 91[mean ± SD] age: 18.19 ± 2.37 year; height: 172.1 ± 9.8 cm; body mass: 68.9 ± 14.5 kg; BMI: 23.15 ± 3.2 kg m-2; body fat: 19.59 ± 6.9%) using underwater weighing (UWW), ADP, and SKF assessments. A 3-compartment (3C) model (i.e., UWW and total body water) served as the criterion, and alternate body density (Db) estimates from ADP and multiple SKF equations were obtained. Validity metrics were examined to establish each method's performance. Bioelectrical impedance analysis (BIA), bioimpedance spectroscopy (BIS), and the SKF equations of Devrim-Lanpir, Durnin and Womersley, Jackson and Pollock (7-site), Katch, Loftin, Lohman, Slaughter, and Thorland differed from criterion. Results: For females, Pearson's correlations between the 3C model and alternate methods ranged from 0.51 to 0.92, the Lin's concordance correlation coefficient (CCC) ranged from 0.41 to 0.89, with standard error of the estimate (SEE) ranges of 1.9-4.6 kg. For SKF, the Evans 7-site and J&P 3 Site equations performed best with CCC and SEE values of 0.82, 2.01 kg and 0.78, 2.21 kg, respectively. For males, Pearson's correlations between the 3C model and alternate methods ranged from 0.50 to 0.95, CCC ranges of 0.46-0.94, and SEE ranges of 3.3-7.6 kg. For SKF, the Evans 3-site equation performed best with a mean difference of 1.8 (3.56) kg and a CCC of 0.93. Discussion: The Evans 7-site and 3-site SKF equations performed best for female and male athletes, respectively. The field 3C model can provide an alternative measure of FFM when necessary.

Acute Bilateral Salter-Harris II Distal Radii Fractures in a Skeletally Immature Athlete.

Distal radius fractures are a common location of physeal injuries in skeletally immature adolescents. However, reports of athletics-related acute bilateral distal radius physeal injuries are rare. Therefore, there is a need for further literature to demonstrate both the early recognition and prevention of these injuries to ensure young athletes are able to safely train and compete. We present the case of acute bilateral Salter-Harris II distal radii fractures in a 14-year-old athlete during participation in a high-energy impact sport.

Relationship between Physical Performance, Anthropometric Measurements and Stroke Velocity in Youth Tennis Players.

Given that serve velocity has been identified as one of the most important components influencing performance in tennis, identifying the factors associated with serve velocity is crucial for coaches and athletes. The aim of this study was to describe the relationship between physical performance, anthropometric characteristics and stroke velocity in youth tennis players. Twenty-seven youth players (male = 16, age = 15.69 ± 1.70 years; female = 11, age = 15.82 ± 1.40 years) underwent an anthropometric and physical performance assessment. On a tennis court, players were assessed for forehand, backhand and serve velocities. Pearson's correlation coefficient revealed that forehand velocity was significantly correlated with height (r = 0.58) and handgrip strength (right hand: r = 0.68; left hand: r = 0.57), whereas backhand velocity was significantly correlated with running time (r = 0.52) and handgrip strength (right hand: r = 0.67; left hand: r = 0.55) in males. Similarly, in males, serve velocity was significantly correlated with height (r = 0.60), running time (r = 0.62) and handgrip strength (right: r = 0.77, left hand: r = 0.71). In females, a significant correlation was only demonstrated between serve velocity and body weight (r = 0.69). These findings highlight that handgrip strength, running time and body height variables are positively associated with stroke velocities in male youth tennis players.

Understanding Youth Athlete Motivation, Training, and Activity Progression During and After the COVID-19 Sports Interruption.

Background: COVID-19 restrictions created a period of disrupted sports participation for youth athletes. The physical conditioning, sports training habits, and patterns of sports activity resumption upon returning to normal sports activity are currently unknown. Purpose/Hypothesis: This study aimed to determine the extent to which youth athletes maintained their training levels during the early stages of the COVID-19 pandemic and understand the strategies that enhanced motivation and adherence to a training regimen while in isolation. A secondary aim was to analyze how youth athletes returned to activity and identify injuries associated with prolonged sports interruption. Study Design: Observational / Survey Study. Methods: A survey designed to determine activity changes, type of organized instruction, and athlete preferences for training support were distributed by email using snowball sampling methodology to athletes 14-21 years old who were involved in competitive sports when pandemic restrictions were enacted. As sports activities resumed, a follow-up survey was distributed to the same respondents to identify feelings of preparedness, training habits, and injuries. Results: Of the155 subjects (mean age 16.1 ± 2 years, 64.5% female) that completed the initial survey, 98% reported a stoppage of in-person sports participation and 70% decreased their exercise/training volume, with 41% (n=63) reporting > 50% reduction. Most athletes (86%) received instruction from coaches, with written workouts (70%) being most common; however, most athletes (70%) preferred instructor-led, group training sessions. Of the 43 subjects that completed the follow-up survey (34% response rate), there was an increase in athletic exposures compared to mid-pandemic levels, and 25% reported sustaining a sports-related injury shortly after resuming sports activities. Conclusions: Pandemic-related sports restrictions resulted in a significant reduction in youth athlete training and conditioning. Coaches attempted to maintain training via the use of written workouts; however, athletes preferred instructor-led, group training sessions. There was a rapid resumption of sports activities, which may have contributed to the high rate of injuries in this study. Level of Evidence: 3.