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Heart rate variability (HRV) is a non-invasive health and fitness indicator, and machine learning (ML) has emerged as a powerful tool for analysing large HRV datasets. This study aims to identify athletic characteristics using the HRV test and ML algorithms. Two models were developed: Model 1 (M1) classified athletes and non-athletes using 856 observations from high-performance athletes and 494 from non-athletes. Model 2 (M2) identified an individual soccer player within a team based on 105 observations from the player and 514 from other team members. Three ML algorithms were applied -Random Forest (RF), Extreme Gradient Boosting (XGBoost), and Support Vector Machine (SVM)- and SHAP values were used to interpret the results. In M1, the SVM algorithm achieved the highest performance (accuracy = 0.84, ROC AUC = 0.91), while in M2 Random Forest performed best (accuracy = 0.92, ROC AUC = 0.94). Based on these results, we propose an athleticism index and a soccer identification index derived from HRV data. The findings suggest that ML algorithms, such as SVM and RF, can effectively generate indices based on HRV for identifying individuals with athletic characteristics or distinguishing athletes with specific sports profiles. These insights underscore the importance of integrating HRV assessments systematically into training regimens for enhanced athletic evaluation.

The purpose of the current study was to determine the test-retest reliability and concurrent validity of a photoplethysmography (PPG) finger sensor when collecting heart rate variability (HRV) metrics in reference to electrocardiography (ECG) and heart rate monitor (HRM) devices. Five minutes of R-R interval data were collected from 45 participants (23 females; age: 23.13 ± 4.45 yrs; body mass index: 25.39 ± 4.13 kg/m²) in the supine and seated positions in testing sessions 48 h apart. Moderate-to-excellent test-retest reliability of the HRV data collected from the PPG sensor was identified (ICC_2,1 = 0.60-0.93). Additionally, similar standard errors of the mean, coefficient of variation, and minimal detectable change metrics were observed across all devices. Statistically significant (p < 0.05) differences were identified in the HRV data between the PPG sensor and ECG and HRM devices; however, these differences were interpreted as trivial-to-small (g = 0.00-0.59). Further, the PPG sensor tended to only overestimate HRV metrics by <0.5 ms and near perfect relationships (r = 0.91-1.00) and very large-to-near perfect agreement (CCC = 0.81-1.00) were identified between collection methods. The PPG sensor demonstrated adequate test-retest reliability and concurrent validity in both the supine and seated resting positions.

Muscular strength and explosiveness are generally known as factors that affect physical performance. Physical ability modeling has a profound connection with long-term athlete development and talent identification. The purpose of the current study was to investigate differences in contractile characteristics (maximal isometric force and maximal rate of force development) among various muscle groups in youth elite female team handball players (n = 35, 16.6 ± 1.1 years) compared to a control group (n = 28, 16.7 ± 1.1 years). The following tests were performed: isometric non-dominant hand grip, isometric dominant hand grip, isometric deadlift, isometric standing leg extension, and isometric bilateral ankle extension. For each subject, the maximal isometric force and maximal rate of force development were derived from the isometric strength tests. The research analyzed a total of twenty-four variables, presented in both absolute and relative values. Statistical analysis revealed significant differences among all pairs of variables in the absolute values of maximal isometric force (Λ = 0.531, F = 10.07, p = 0.000) and maximal rate of force development (Λ = 0.692, F = 5.08, p = 0.001) between the two groups. The most significant difference was found in the grip of the dominant hand, where the impact of the difference was 43.6% and 37.0% for the absolute values of force and explosiveness. Conversely, no differences were observed between the pairs of variables representing the relative values across the two subject groups, except for the dominant hand grip relative force (p = 0.006). The results provide information about the contractile potentials of important muscle groups in the game of handball, which could help in adapting strength training according to the specifics of the strength and explosivity development of young female handball players.

The present study aimed to verify the (1) differences between players' roles in relation to technical and tactical and time-motion indicators, and the (2) relationships between individual time-motion and technical and tactical indicators for each role in a men's Italian football Serie A team. A total of 227 performances were analyzed (28 players: 8 forwards, FWs; 11 midfielders, MDs; 9 defenders, DFs). Technical and tactical indicators, such as ball possession (played balls, successful passes, successful playing patterns, lost balls, ball possession time), offensive play (total and successful dribbles, crosses, assists), and shooting (total shots, shots on target) were obtained by means of Panini Digital (DigitalSoccer Project S.r.l). In addition, a time-motion analysis included the total distance, distances covered at intensities of 16.0-19.8 km/h, 19.8-25.2 km/h, and over 25.2 km/h, the average recovery time between metabolic power peaks, and burst occurrence, the latter of which was performed by means of a 18 Hz GPS device (GPexe Pro2 system tool) worn by the players. Results showed role-specific differences: MDs covered more distance, while DFs had better ball possession. MDs and DFs had more successful playing patterns, and MDs and FWs performed more dribbles and shots. Strong correlations (p < 0.01, ρ > 0.8) were found between bursts and assists for FWs, high-intensity running and ball possession for MDs, and distance, dribbling, and shots for DFs. These findings highlight the importance of individual and tailored training programs to optimize role-specific performance demands.

Background: Speed training with resisted sprints has been shown to positively affect neuromuscular performance in soccer players. Various loads, ranging from 10% to 120% of body mass, have demonstrated performance improvements across the spectrum. However, the impact of sprint distance with optimal load on these adaptive responses has yet to be thoroughly described.

Objective: To analyze the influence of sprint distance in resisted sprints on muscle performance in young soccer players.

Methods: This quantitative study utilized a pre-post experimental design. The sample consisted of 24 young soccer players (15.3 ± 0.68 years; 61.4 ± 7.08 kg; 1.60 ± 0.06 m) randomized into three groups (10, 20, and 30 m) and subjected to 12 sessions of resisted sprint training over six weeks. The volume was homogenized across groups, with a total distance of 120 m for each. The intervention's effect was analyzed through performance in the isometric mid-thigh pull (IMTP), countermovement jump (CMJ), modified 505 agility test (505 m), and linear sprint tests. Differences were analyzed using a mixed ANOVA, incorporating a between-subjects factor (training group) and a within-subjects factor (pre- and post-intervention).

Results: Time-dependent differences were observed in all groups for peak force (PF) (p < 0.001; η²p = 0.62), time to PF (TPF) (p < 0.001; η²p = 0.53), impulse at 50 (p < 0.001; η²p = 0.57), 100 (p < 0.001; η²p = 0.60), and 200 ms (p < 0.001; η²p = 0.67) in IMTP; jump height by impulse-momentum (p < 0.001; η²p = 0.64), rate of force development (p = 0.04; η²p = 0.14), yielding impulse (p < 0.001; η²p = 0.49), and concentric impulse (p = 0.01; η²p = 0.19) in CMJ; time (p < 0.001; η²p = 0.46) in 505 m; and average speed in linear sprint (p = 0.003; η²p = 0.36), with moderate to large effect sizes, regardless of the distance covered. No differences were observed for the interaction between the time* and group or between groups.

Conclusion: Performance improvements were independent of the sprint distance, with no differences between training groups. Distances between 10 and 30 m may enhance muscle performance in young soccer players.

Background: High-intensity endurance training induces specific cardiac adaptations, often observed through electrocardiographic (ECG) changes. This study investigated the prevalence of ECG abnormalities in national-level Australian triathletes compared to sedentary controls.

Methods: A cross-sectional observational study was conducted involving 22 triathletes and 7 sedentary controls. Standard 12-lead ECGs assessed resting heart rate, ECG intervals, and axis deviation. Peak oxygen consumption was evaluated in triathletes to correlate with ECG indices and left ventricular mass, derived via echocardiography.

Results: Triathletes exhibited significantly lower resting heart rates (53.8 vs. 72.1 bpm, -34%, p = 0.04), shorter QRS durations (0.088 vs. 0.107 ms, -21.6%, p = 0.01), and longer QT intervals (0.429 vs. 0.358 ms, +16.6%, p = 0.01) compared to controls. Sinus bradycardia was present in 68.2% of triathletes, with varying severity. First-degree atrioventricular block was identified in 13.6% of athletes, and left ventricular hypertrophy was confirmed in 18 triathletes via echocardiography. A significant positive relationship was identified between VO₂peak and left ventricular mass (r = 0.68, p = 0.003).

Conclusions: National-level triathletes exhibited ECG and structural cardiac adaptations consistent with high-intensity endurance training. Echocardiography is recommended for the accurate identification of LVH. These findings highlight the need for comprehensive cardiac evaluation in athletes to distinguish between physiological and pathological adaptations.

To reduce the risk of syncope, trained breath-hold divers (BHDs) use a specialized breathing technique after surfacing called "hook breathing" (HB). It consists of a full inspiration followed by a Valsalva-like maneuver and with subsequent exhalation performed against resistance to generate continuous positive airway pressure during exhalation. This study analyzed the influence of HB on oxygen saturation recovery after a -40 m depth apnea dive in trained BHDs. Thirteen BHDs performed two dives to -40 m at different days, one followed by HB after a dive and the other using usual breathing (UB). To detect signs of lung edema, ultrasound B-line measurements were conducted before, 10 min after the dive, and within 1 h after the dive. To detect oxygen saturation recovery, pulse oximetry was recorded before and immediately after surfacing. Both groups exhibited significant increases in SpO₂ over time (UB: F (2.25, 24.7) = 22.1, p < 0.001, ηg2 = 0.612; HB: F (2.11, 23.2) = 29.0, p < 0.001, ηg2 = 0.688). Significant differences in SpO₂ were observed between the HB and UB groups at 30-45 s post-apnea, with higher SpO₂ values in the HB group; between 1.64 and 5.08% of SpO₂ in favor of the HB intervention. Four participants showed ultrasound B-lines within ten minutes post-dive. After a 40 m apnea dive, the results revealed significant SpO₂ recovery from 30 s to 45 s, with the HB recovering more rapidly. No differences were found at earlier (10-25 s) or later time points (50-60 s).

Background: Schizophrenia is classified by the World Health Organization (WHO) as one of the top ten diseases contributing to the global medical economic burden. Some studies have pointed out that exercise is effective for physical and mental health, as well as cognition. We hypothesized that participation in pickleball intervention would lead to improved self-esteem and reduced psychiatric symptoms in schizophrenia patients. Method: We recruited participants with schizophrenia from a long-term care facility and a regional hospital, dividing them into two groups based on the institutions. The experimental group underwent a nine-week pickleball exercise intervention, with sessions three times a week, each lasting 90 min, and a Dink ball test was conducted weekly. Questionnaires on self-esteem and the short-form health survey were collected both before and after the intervention. Result: This trial included 30 patients, divided equally into the experimental group (n = 15) and the control group (n = 15). After the nine-week pickleball intervention, there were no significant differences between the experimental and control groups in the Rosenberg Self-Esteem Scale (RSES) (p = 0.153) or the Brief Symptom Rating Scale (BSRS-5) (p = 0.289). However, the Dink test scores in the experimental group showed significant improvements in physical activity capabilities and attention over time, with average hit counts increasing from 5.3 ± 1.5 to 10.7 ± 2.3 (p < 0.01). Conclusions: Although the pickleball intervention did not yield significant differences in self-esteem and symptom measures between groups, the improvements observed in physical performance and attention in the experimental group suggest that exercise remains a feasible complementary approach for managing schizophrenia symptoms. Further research with larger sample sizes is recommended.

Trauma-induced shoulder dislocations and sprains rank among the most common upper extremity injuries, with contact sports accounting for the majority of cases. These injuries often lead to substantial impairments in joint function and long recovery times, requiring targeted therapeutic interventions to restore mobility and prevent recurrent injuries. Given the pivotal role of exercise therapy in restoring shoulder function, this study systematically reviews the literature on the comparative effectiveness of supervised versus self-managed exercise therapy following acute shoulder trauma. PubMed, Cochrane CENTRAL, Embase, Web of Science, and Science Direct were searched up to 13 December 2024. Conservative and post-surgical treatment modes were analyzed separately. Five studies with a total 689 participants were included (conservative: n = 538 across two studies; post-surgical: n = 151 across three studies). Both treatment modes showed similar pooled effects (standardized mean difference, SMD_conservative: -0.35, 95% CI [-1.39, 0.69]; SMD_{post-surgical}: -0.23, 95% CI [-1.21, 0.75]), with a marginal improvement in shoulder function favoring supervised therapy. Four studies had some risk of bias, and one had serious risk; GRADE certainty was low. Supervised exercise therapy may offer slightly greater functional improvements over self-managed training, but evidence is limited by heterogeneity and low certainty. Further high-quality trials with standardized protocols and improved adherence tracking are needed to establish more definitive conclusions and guide clinical decision-making.

Introduction: Injury and illness rates within cycling are a growing concern for riders, medical personnel, and event organisers. This study is the first to document injury and illness rates in professional cyclists throughout one competitive season including training and racing. Methods: A prospective, longitudinal study was conducted with 47 professional cyclists (30 males and 17 females) over the 2024 season (1 November 2023-31 October 2024). Injuries and illnesses were defined and recorded following the International Olympic Committee (IOC) consensus guidelines for injury reporting in sports and its cycling-specific extension. Data collection utilised a centralised online hub, integrating exposure metrics (e.g., training hours and kilometres) and medical records. All data were processed on a Macintosh computer using the Microsoft Office and R statistics packages epi tools, binom.test function, and ggplot. (V.4.3.2, R Foundation for Statistical Computing, Vienna, Austria). Ethical approval was obtained from Queens University Belfast, number MHLS 23_175. Results: Fifty-five injury events were logged, with 1.15 (±0.359) locations injured per incidence and 1.57 (±1.06) injury types per incident. The overall combined injury rate for racing was 4.14 (95% CI: 2.65-5.79) per 1000 h of exposure, with the overall combined rate for training being 1.23 (95% CI: 0.8-1.7) per 1000 h. The injury risk ratio (RR) for injury during racing and training for females was 11.10 (95% CI: 2.69-37.60), and the RR for males was 10.24 (95% CI: 3.84-43.06), both indicating there is a significantly higher risk of injury during racing compared to training. Abrasions were the most common injury type, with fractures being the most burdensome injury. The most common illness was upper respiratory, 0.63 (95% CI: 0.27-0.99) per year for males and 1.11 (95% CI: 0.64-1.59) per year for females. Saddle sores were the second most common at 0.20 (95% CI: 0.04, 0.36) per year for males and 0.08 (95% CI: 0-0.18) per year for females. Conclusions: This study provides the first comprehensive, season-long surveillance data for injuries and illnesses in male and female professional road cycling, highlighting the significant differences in injury profiles between racing and training. These results underscore the need for targeted injury prevention strategies and the establishment of a standardised injury and illness framework for professional cycling.