This study aimed to examine whether hip deformity has already developed in Japanese male freshman collegiate long-distance runners and to investigate the association with their sports history.A total of 57 elite freshman collegiate long-distance runners participated. We collected sports history data during adolescence using a questionnaire, and hip images were measured using dual-energy X-ray absorptiometry. Cam morphology was defined based on visual scores of the anterior head-neck junction, classified as follows: (i) normal, (ii) flattening, and (iii) prominence. Pincer morphology was defined as a bony prominence or osteophyte-like protrusion at the acetabular rim.Cam morphology based on visual scores was found in 78 of 114 hips (68.4%; 40 right and 38 left). Pincer morphology based on visual scores was found in 73 of 114 hips (64.0%; 39 right and 34 left). There was no significant association between hip deformity and sports participation history ( p >0.58). In an additional exploratory non-athletic cohort, a similarly high prevalence of cam and pincer morphology was observed (cam: 14 of 18 hips [77.8%]; pincer: 13 of 18 hips [72.2%]). These may indicate that factors beyond participation in multidirectional sports, including internal factors, could contribute to hip morphology.
Abstract In this cross-sectional study, we aimed to describe preseason hip abduction and adduction strength in Division III cross-country athletes using an externally fixated inline tension dynamometer to report sex-stratified normalized torque values (Nm/kg) and adduction:abduction ratios. Maximal isometric hip abduction and adduction peak forces were measured during a single session and normalized to body mass and moment arm length. Participants included 35 male runners (18.9±0.90 y) and 26 female runners (19.0±1.1 y). Normalized hip torque (Nm/kg) (right/left) for men was: abduction (1.82±0.38/1.84±0.36), adduction (1.98±0.43/1.70±0.41), and adduction:abduction ratio (1.10±0.18/0.92±0.12). Normalized hip torque (Nm/kg) (right/left) for women was: abduction (1.45±0.25/1.43±0.27), adduction (1.40±0.22/1.34±0.28), and adduction:abduction ratio (0.98±0.14/0.95±0.15). By accounting for joint moment arm length and body mass while minimizing measurement variability through rigid external fixation, this study establishes sex-stratified normative isometric hip strength reference profiles in healthy collegiate distance runners to support baseline strength profiling and standardized clinical screening.
It is firmly established that balance training leads to significant improvements in postural control in youth. However, little is known about how differences in balance training distribution (i.e., how total training volume is scheduled: duration×frequency), despite the equal total training volume, affect training-induced adaptations. This study was aimed at determining the effect of balance training distribution on balance performance. Twenty-five adolescents (15.8±0.6 y) were randomly assigned to either a 4-week balance training-3×/wk group (massed practice: 4 weeks of balance training for three sessions/wk) or a 6-week balance training-2×/wk group (distributed practice: 6 weeks of BT for two sessions/wk) group. Balance assessments included the timed One-Legged Stance test and the Y Balance Test Lower-Quarter. Significant pretest to post-test improvements were detected for all parameters of the One-Legged Stance test and Y Balance Test Lower-Quarter, irrespective of balance training distribution. Additionally, a group×test interaction ( p =0.041 and η p 2 =0.17) was detected for the posterolateral reach distance in favor of the massed practice group. These findings highlight that most outcomes improved regardless of balance training distribution, and only one outcome showed a benefit for the combination of shorter balance training duration with higher balance training frequency (i.e., massed practice) than vice versa (i.e., distributed practice).
Statistical inference underpins the credibility of sports science research, yet concerns remain regarding the rigor of statistical reporting and analysis. This study assessed the adequacy of statistical practices in sports science research according to established methodological guidelines. A total of 167 original studies published in 2020 across 15 sports science journals indexed in the Journal Citation Reports (Q1-Q3) were systematically reviewed. Up to 50 studies per journal were randomly selected, and data regarding study characteristics and statistical methods were extracted. Statistical adequacy was classified according to predefined criteria involving reporting omissions and/or statistical misapplications. Overall, 87.4% of studies presented at least one inadequacy. The most frequent reporting omissions involved failure to report assumptions such as normality, homogeneity of variances, and sphericity when required. Common statistical misapplications included the use of inappropriate dependent variables and incorrect treatment of independent observations as dependent measures. Deficiencies were identified across all journal quartiles, with no association between adequacy and journal ranking ( p =0.586). These findings raise concerns regarding validity, reproducibility, and practical interpretation in sports science research, reinforcing the need for greater statistical literacy, stricter reporting standards, and improved peer review practices.
This study aimed to evaluate training workload and injury history in specifically professional roundnet athletes. An anonymous survey regarding players' injuries specific to roundnet was created with input from two premier roundnet athletes and two orthopedic surgeons. The 56 Spikeball Tour Series professional roundnet athletes from the 2023 season were contacted after the 2023 season to complete an anonymous injury history survey. Overall, 49 (88%) of the 56 professional roundnet athletes from the 2023 season were included in the study. Professional roundnet athletes had been competing in roundnet for a mean of 4 years and train 9.5 months per year. Players reported 82 roundnet injuries comprised of 43 (52%) upper extremity injuries, 24 (29%) lower extremity injuries, and 15 (18%) axial injuries. No reported injuries required surgical treatment. Upper extremity, lower extremity, and axial injuries had an average time to return to sport (RTS) of 1.8 months, 2.8 months, and 2.2 months missed, respectively. In conclusion, the upper extremity is the most commonly injured region in professional roundnet athletes, accounting for about half of roundnet injuries. Professional roundnet athletes most frequently experience significant acute injuries of the elbow and ankle, and significant chronic injuries of the shoulder and lower back.
Bodyweight exercises and weightlifting are foundational to strength training, yet their relative public health burdens remain poorly defined in large, nationally representative samples. We analyzed data from the National Electronic Injury Surveillance System from 2014 to 2023. A standardized keyword screening protocol was utilized to identify cases of weightlifting and bodyweight injuries treated in US emergency departments. Variance estimation was performed using Taylor series linearization to account for the complex, stratified sampling design and generate nationally representative estimates. Over the 10-year study period, national estimates of 546,655 weightlifting-related injuries and 108,001 bodyweight-related injuries were identified. Weightlifting injuries primarily involved the trunk (70.1%) and phalanges (13.7%). Bodyweight injuries were significantly associated with upper and lower extremity trauma (20.7%) and joint dislocations (8.7%). After adjusting for age and sex in a cluster-robust multivariable model, exercise modality was not a significant predictor of inpatient hospitalization (adjusted odds ratio: 0.91; 95% confidence interval: 0.60-1.38; p =0.666). While weightlifting poses a higher absolute volume burden, there is no significant difference in hospitalization odds when adjusting for age and sex. Prevention should focus on a suitable technique for heavy lifts and safe joint positioning for dynamic bodyweight movements, with increased diagnostic precaution and safety monitoring recommended for older participants.
Heat strain in multiple sclerosis patients during exercise limits their benefits from this treatment. One prior study examined this topic but did not measure thermal outcomes and constitutes a knowledge gap. The current pilot study assessed palm cooling for its impact on heart rates and thermal measures. Using a randomized within-subjects design, nine multiple sclerosis patients performed two 25-minute cycle ergometry workouts against 65 and 45% of their Astrand-Rhyming-based workloads. Heart rates, thermal flux, palm and tympanic temperatures were examined using two-way analyses of variance with repeated measures per independent variable. To control the family-wise error rate, a Bonferroni correction was applied at a lower α level of 0.0024. Paired t -tests identified sources of significant inter-treatment and -time differences. Palm temperature, thermal flux, and heart rate had significant two-way interactions. Palm temperature ( η 2 p =0.39) and heart rate ( η 2 p =0.22) results were significantly higher for the no palm cooling treatment at multiple times during and after workouts. Yet, thermal flux ( η 2 p =0.39) was significantly higher due to palm cooling at multiple times during and after workouts. Higher thermal flux from palm cooling may have evoked lower heart rates. Palm cooling may represent a practical strategy to mitigate exercise-induced heat strain in individuals with multiple sclerosis.
Emerging evidence suggests that training at longer muscle lengths may optimize muscle hypertrophy. Of note, there is an interplay between muscle length, range of motion (ROM), and exercise selection. It is difficult to identify whether muscle length per se is the main factor, limiting the ability to draw practical conclusions. Thus, synthesizing these different lines of investigation may help to clarify this topic. Firstly, we offer a comprehensive understanding of the physiological effects arising from muscle contractions in longer, moderate, and shorter muscle lengths. Subsequently, we conducted an unstructured review of long-term studies comparing muscle hypertrophy following: 1) isometric training at different muscle lengths, 2) training with different ROMs, and 3) exercises that train muscles at different muscle lengths and/or with different resistance profiles. Different lines of investigation suggest that muscle length plays a role, as training at longer muscle lengths elicits more favorable muscle growth. Notably, the greater muscle growth often observed after exercises and ROMs that train muscles at longer lengths occurs when there is a relevant external torque in the lengthened position. From a practical perspective, the selection of exercises and ROMs that impose relevant external torque at longer muscle lengths should be considered to optimize muscle growth.
Body composition analysis in adolescent athletes is critical for assessing fat mass percentage and fat-free mass. However, measurement inaccuracies can compromise results. Additionally, there is a lack of reliable reference methods to evaluate the accuracy of field measurement techniques. This review evaluates the reliability and validity of methods in adolescent athletes and provides evidence-based recommendations for best practice. The search (Pubmed and Scopus) followed Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines and PICO criteria related to adolescent athletes in bioelectrical impedance analysis, dual-energy X-ray absorptiometry, air displacement plethysmography and skinfold thickness measurements. Thirty-one studies out of 4,408 records met the eligibility criteria. Estimating fat mass percentage and fat-free mass in adolescent athletes is moderately reliable and valid. Dual-energy X-ray absorptiometry is often regarded as the criterion standard particularly for validating equations in bioelectrical impedance analysis and skinfold measurements. Its assumptions regarding tissue density and confounding factors limit precision. Air displacement plethysmography and hydrostatic weighing are limited in athletes with extreme body mass or atypical fat distribution. Recent calculation formulas validated for adolescents are rare and inadequate for athletes. In summary, two- and three-compartment models reflect reduced accuracy in adolescent athletes, making four-compartment models preferable. Field methods like bioelectrical impedance analysis and skinfolds require further validation due to the lack of reliable reference methods in this specific population.
Little is known about how individual and contextual factors affect inter-limb differences in balance performance. Thus, we investigated how these factors influence inter-limb asymmetry in balance. Sixty-four soccer players with diverging levels of training experience (i. e., 2–5 or 6–9 years), 73 swimmers, and 60 age-matched non-athletes performed balance tests with different task specificity (i. e., ecological vs. non-ecological). The magnitude of inter-limb differences was quantified by calculating the limb symmetry index (LSI). Inter-limb performance differences were significantly (p=0.012) lower in athletes with (i. e., soccer players) than without (i. e., swimmers) the preferential use of one leg for postural control. However, differences between limbs did not significantly differ among players with diverging levels of training experience. Further, the observed inter-limb differences in soccer players emerged during ecological test conditions only. Our results suggest that the predominant use of one limb compared to the other for balance requirements does not necessarily lead to a large magnitude of inter-limb asymmetry in soccer players and is also not significantly influenced by the level of training experience. However, from a practitioners’ perspective, ecological as opposed to non-ecological test conditions seem to be more suitable for detecting inter-limb asymmetry in soccer players.
We aimed to investigate the effects of hot-water immersion of the hand and forearm during half-time (HT) on the physiological responses, leg muscle strength, and cycling sprint performance in the cold. Ten recreationally active men performed the experimental trials that consisted of 40 min intermittent cycling, followed by a 15-min HT, and then an intermittent cycling sprint test in a cold (5°C and 50% relative humidity). During HT, the participants underwent two different interventions: seated rest (CON) or hand and forearm heating (HEAT). The intermittent cycling sprint test comprised 10 sets of 5 s of maximal pedaling and 25 s of recovery. In addition, the participants performed maximal voluntary contraction (MVC) in knee extension before and after HT. Although the peak power output in the intermittent cycling sprint test did not significantly differ between trials (p>0.05), the rectal temperature (T re ) following HT in HEAT was significantly higher than in CON (p=0.026). In addition, the MVC force after HT was significantly higher in HEAT than in CON (p<0.001). This suggests hot-water immersion of hand and forearm during HT improves knee extensor muscle strength and attenuates the T re decrease in a cold environment.
In the management of overweight, the implementation of exercise helps to create a caloric deficit and to lose weight. Several studies have shown poor reporting quality of exercise interventions for other diseases. Thus, the purpose of this study was to assess the completeness of exercise intervention reporting in randomized controlled trials (RCTs) for the treatment of overweight and to evaluate potential differences between exercise modalities. Two independent reviewers applied two intervention reporting guidelines to 47 RCTs on the management of overweight. The completeness of intervention reporting was evaluated using descriptive statistics. Potential differences in reporting quality between studies using aerobic exercise (AE) vs. studies using combined aerobic and resistance exercise (ARE) were calculated with a χ2 test. Overall, studies completed 61% and 47%, respectively, of the guideline items. The χ2 analysis of exercise modalities showed a significant difference for two items regarding exercise progression (91% AE vs. 38% ARE, p<0.001) and detailed description of exercises (0% AE vs. 50% ARE, p<0.001). Reporting of exercise interventions in the treatment of overweight was found insufficient. The detected differences between exercise modalities imply the need for improved guidelines.
Although the function movement screen (FMS) has been widely used in the general population, no study to date has used the FMS as a preparticipation screen for individuals with breast cancer (BC) engaging in an exercise regimen. Even though individuals with BC are anthropometrically similar to individuals without cancer, the lack of studies assessing the FMS in individuals with BC may potentially hinder exercise prescription. Therefore, we aim to examine the relationships of the FMS score to anthropometric biomarkers in individuals with BC before undergoing an exercise regimen. One-hundred and twelve women with BC underwent a thrice-weekly three-month dose-escalated exercise regimen utilizing multi-joint compound movements and linear progression balanced with resistance training volume to elicit hypertrophy. FMS score and anthropometric markers were assessed pre- and post-intervention. With significance set at p≤0.05, baseline FMS scores correlated significantly with all anthropometric markers, and was similar to previous studies published in non-cancer populations. However, baseline FMS scores were not associated with changes in anthropometric markers, from pre- to post-intervention. While the baseline FMS score was not associated with changes in anthropometric markers, the similar correlation found in our study compared to previous studies suggest that the FMS can be used as a preparticipation in individuals with BC to help guide the exercise regimen. Future studies designed to elicit weight loss in individuals with BC should assess whether the baseline FMS score is predictive of anthropometric changes.
The main purpose of this study was to assess relationships between absolute and relative handgrip strength (HGS) versus other markers of health (body composition) and physical fitness (VO2 max, vertical jump) in 220 (112 male) healthy young adults (25±10 years). HGS was measured using a hand dynamometer. Absolute HGS represented the highest grip strength measurement (kg) of the right and left hand combined, while relative HGS represented the absolute HGS divided by body weight (kg/kg). Body composition (lean and fat mass) was measured using dual energy x-ray absorptiometry. VO2 max was measured using a treadmill peak speed protocol (ml/kg/min), while vertical jump was assessed using a countermovement jump (cm). Absolute HGS (mean=86±22 kg) was positively related with lean mass (r=0.82, p<0.001) and vertical jump (r=0.63, p<0.001), while relative HGS (mean=1.2±0.2 kg/kg) was negatively related with body fat (r=–0.69, p<0.001), but positively correlated with VO2 max (r=0.47, p<0.001), and vertical jump (r=0.45, p<0.001). Linear models suggest that lean mass, body fat, and vertical jump predicted 69% of variance for absolute HGS (adjusted R2=0.71, p<0.001), while lean mass and body fat predicted 49% of variance for relative HGS (adjusted R2=0.49, p<0.001). Lower relative HGS scores (<1.0 kg/kg) were associated with higher body fat levels and may represent a quick, simple, marker of health.
Post-activation performance enhancement (PAPE) occurs when performance improves after intense contractile stimulation. This study examined the effect of pubertal status on PAPE after a maximal cardiopulmonary exercise test (CPET) in 48 male soccer players aged 10–18 years. Additionally, we investigated the relationship between maximal aerobic speed (MAS) and lower limb strength. They were classified as pre-pubescent (n=13), pubescent (n=15), and post-pubescent (n=20). The participants performed three countermovement jumps (CMJ) before and after a maximal CPET. The PAPE was estimated by calculating the difference between pre- and post-exercise CMJ height at five minutes of recovery after CPET. The CPET was performed on a treadmill using a ramp protocol to determine the maximal oxygen consumption (VO2 max) and MAS. CMJ height was significantly greater after the CPET for all groups. Post-pubescent participants had significantly greater PAPE than both pre-pubescents and pubescents. Pre-pubescents had significantly lower CMJ height, VO2 max, and MAS compared to pubescent and post-pubescents. Finally, a positive relationship was observed between MAS and CMJ height. In conclusion, PAPE after maximal CPET was observed in all pubertal cohorts of young soccer players. However, it was greater in post-pubescent children. Finally, MAS was positively correlated with lower limbs strength.
The benefits of exercise have been well described for the treatment of hypertension. Poor reporting quality impairs quality appraisal and replicability. High intensity interval training (HIIT) has been shown to be an effective alternative to traditional aerobic exercise in patients with hypertension. We evaluated the completeness of reporting of randomized controlled trials (RCTs) with HIIT for hypertension and to compare both exercise modes in reporting quality. RCTs of HIIT with a minimum duration of 6 weeks in adults with at least high normal blood pressure (≥130 mmHg/≥85 mmHg) were evaluated using the Consensus on Exercise Reporting Template (CERT). Nine RCTs conducting HIIT in hypertensive patients (N=718; 51.8 years) were evaluated. A mean of 62.6% of items were sufficiently described, compared with 49.2% in moderate intensity training interventions. Exercise dose was adequately reported in 8 out of 9 studies. Only one study reported information on adverse events. In a small sample of RCTs with HIIT in patients with hypertension we found a better reporting quality than in moderate intensity training interventions. However, reporting completeness is not optimal for a good replicability in clinical practice. The lack of reporting of adverse events in interventions using high intensities is particularly unfavourable.
In order to assess how well hand grip strength can predict spinal muscle size and to determine if scaling improves prediction Biobank data was acquired consisting of hand grip strength, age, height, body mass and abdominal magnetic resonance images for 150 age-matched male and female participants. The cross-sectional area of the multifidus and erector spinae was measured from the images at the L3/L4 level. Correlation strength and prediction errors were quantified for muscle size predicted from hand grip strength, age, height, and body mass. The effect of scaling muscle area by height and height squared was also determined. All variables correlated significantly with spine muscle size. The strongest correlator was hand grip strength (r = 0.61, p < 0.05) with a prediction error of 678 mm2. The strength of the correlations was reduced when muscle areas were scaled. Hand grip strength can predict spine muscle size in male and female participants; however, the confidence intervals on the predicted values are larger than would be expected from measuring muscle size directly using imaging technologies. Scaling by height or height squared does not improve the ability of hand grip strength to predict muscle size.
Field hockey, a physically demanding Olympic sport, carries a high risk of lower limb injuries, yet data on injury risk in elite field hockey are limited. Functional knee stability is important for injury prevention and a safe return to sport. This study is the first to investigate functional knee stability in elite field hockey, considering gender and playing class, and establishes reference data for functional knee stability by using a standardized test battery that assesses one- and two-legged stability, jumping tests, speed, and agility. Seventy-two elite field hockey players, 30 males and 42 females (age 19.82±3.74 years) were divided into High Playing Class (HPC) and Moderate Playing Class (MPC). HPC players showed significantly better performance in all functional tests except balance tests ( p <0.01-0.024). Females showed significantly better one- and two-leg stability ( p <0.01) with lower injury rates, indicating the relevance of gender considerations. The study emphasizes the importance of balance and stability in the prevention of lower limb injuries in Olympic field hockey and also highlights the importance of considering pre-existing deficits in functional knee capability when assessing athletes for return to sport. These results can help improve athletic performance, identify individual strengths and weaknesses, prevent injury or re-injury, and facilitate return to sport after injury.
We introduce a novel approach for predicting running performance, designed to apply across a wide range of race distances (from marathons to ultras), elevation gains, and runner types (front-pack to back of the pack). To achieve this, the entire running logs of 15 runners, encompassing a total of 15,686 runs, were analyzed using two approaches: (1) regression and (2) time series regression (TSR). First, the prediction accuracy of a long short-term memory (LSTM) network was compared using both approaches. The regression approach demonstrated superior performance, achieving an accuracy of 89.13% in contrast, the TSR approach reached an accuracy of 85.21%. Both methods were evaluated using a test dataset that included the last 15 runs from each running log. Secondly, the performance of the LSTM model was compared against two benchmark models: Riegel formula and UltraSignup formula for a total of 60 races. The Riegel formula achieves an accuracy of 80%, UltraSignup 87.5%, and the LSTM model exhibits 90.4% accuracy. This work holds potential for integration into popular running apps and wearables, offering runners data-driven insights during their race preparations.
There is evidence that balance performance deteriorates due to exercise-induced muscle fatigue. However, it is unknown if free arm movement during balance testing can compensate for, or restricted arm movement can amplify these performance degradations. Thus, the objective of this study was to compare the effects of free versus restricted arm movement on balance performance under non-fatigued and fatigued conditions. Fifty-two healthy participants (men=31, women=21; age=22.6±1.6 years) were assessed for their dynamic balance (reach distances for the Y Balance Test - Lower Quarter) under non-fatigued and fatigued (repetitive vertical bipedal box jumps until failure) conditions using two different arm positions: free (move the arms freely) and restricted (keep the arms akimbo) arm movement. Restriction of arm movement (all p< 0.001; 0.48≤ η p 2 ≤0.79) and application of fatigue ( p≤ 0.003; 0.16≤ η p 2 ≤0.28) independently, but not the interaction between the two (except for the posteromedial reach direction: p= 0.046; η p 2 =0.08) , resulted in significantly deteriorated lower limb reach distances. These findings suggest that free arm movement and thus the use of an 'upper body strategy' has no compensatory effect on muscle fatigue-induced balance deteriorations.
