Search Results (73)

Background: Adolescence represents a critical period for growth and athletic development, yet young athletes frequently demonstrate significant gaps in nutritional knowledge that can impair performance and long-term health outcomes. Limited research exists on comprehensive nutrition education interventions for adolescent soccer players in North African populations. Objective: To evaluate both general and sports-specific nutritional knowledge among adolescent soccer players from an elite Tunisian club and assess the feasibility of a digital nutrition intervention using mobile application technology. Methods: A cross-sectional survey was conducted between June and August 2024 among 50 male soccer players aged 11–18 years from Étoile du Sahel club in Sousse, Tunisia. Data were collected via a structured questionnaire comprising sections on basic nutrition knowledge, influences on food choices, sports nutrition knowledge and practices, and demographic information. A pilot digital intervention using the FatSecret app was implemented with 8 participants over 4 weeks, involving meal photo uploads and nutritionist feedback. Results: Participants had a mean age of 15.16 ± 1.55 years, with 92% reporting no formal nutrition education. While 90% correctly identified carbohydrates as the primary energy source, only 2% recognized that fat provides the highest energy density. Significant misconceptions existed regarding sports nutrition: 74% incorrectly believed that consuming protein 2–4 h before an event enhances performance, and only 17% knew the recommended pre-event carbohydrate intake. Food choices were primarily influenced by cravings (80%) and sensory appeal rather than health considerations (20%). The digital intervention demonstrated extremely low engagement, with minimal participation in meal photo uploads. Conclusions: This study reveals critical gaps in both general and sports-specific nutritional knowledge among adolescent soccer players in Tunisia, providing important descriptive information about knowledge distribution in this population. While knowledge deficits are substantial, it is important to acknowledge that this cross-sectional assessment documents only knowledge patterns, without measures of actual dietary intake or athletic performance. The persistent misconceptions and the low feasibility of the digital intervention provide important lessons regarding technology-based approaches to nutrition education in this age group, highlighting challenges in sustained engagement that must be addressed in future intervention design. Full article

(1) Background: This study examined the acute and chronic effects of sled-resisted training on power, strength, jump height (evaluated through a CMJ), and sprint kinematics in Spanish amateur football players. (2) Methods: A total of 19 football players (28 ± 8 years; 172 ± 12 cm; 79.3 ± 22.3 kg) performed 10 sled-resisted training sessions with loads of 80% (±2 kg) of their body mass on the day before the match (MD-1). Performance was assessed using a CMJ measured with the My Jump Lab app and sprint kinematics recorded with the 1080 Sprint system; both of these sensor-based technologies are validated for sports performance analysis. The CMJ was performed on MD-1 before the training and again on match day. Sprinting was evaluated before the sled-resisted training and again one week after it ended. (3) Results: These results suggest that sled training with heavy loads and low volume may not have acute effects on CMJ in amateur football players 24 h after it is performed, but there are chronic improvements in CMJ relative force and changes in sprinting after 10 weeks of sled-resisted training. (4) Conclusions: The findings of this study will enable football coaches and physical trainers to understand the changes in this training method to improve performance in amateur football players, using only three repetitions per player per week. Full article

Background: Chronic wrist pain is becoming increasingly recognized among athletes engaging in wrist-loading activities such as handstands. However, its prevalence and associated risk factors in handstand practitioners have not been systematically studied. This study aimed to investigate the prevalence of chronic wrist pain and to explore associated factors such as discipline, training habits, and pain management strategies. Methods: This cross-sectional study aimed to investigate the prevalence and associated factors of chronic wrist pain among handstand practitioners. Eligible participants were individuals aged 18 years or older, of any gender, who practiced handstands regularly (defined as at least once per week). Participants were recruited via a combination of open invitations on social media (Facebook, WhatsApp, Instagram) and direct outreach to movement studios and training communities. The survey was administered online using Google Forms and remained open for two months. Participation was voluntary and anonymous. Descriptive statistics were used to present sociodemographic characteristics, including age group, gender, sport discipline, and weekly training hours. Participants reported training habits, equipment use, pain history, and management strategies via a self-developed questionnaire designed for this study. Chronic pain was defined as recurring or persistent wrist pain. Descriptive statistics were used to summarize responses. Associations between chronic wrist pain and survey variables were analyzed using Chi-square or Fisher’s exact tests for nominal data, and Chi-square test for trend for ordinal data. A p-value < 0.05 was considered statistically significant. Results: A total of 321 participants were included in the study. The most represented age group was 25–34 years, comprising 123 (38.3%) of the participants. Gender distribution was 174 (54.2%) males and 147 (45.8%) females. The most common sport disciplines were Yoga (88, 27.4%), Capoeira (60, 18.7%), and Movement (52, 16.2%). Chronic wrist pain was reported by 182 (56.7%) of participants. Younger age was significantly associated with higher pain prevalence (p = 0.042). No significant associations were observed between chronic pain and weekly training hours, warm-up routines, brace use, or grip device use. Female participants demonstrated more proactive pain management behaviors (p = 0.016). Sport discipline and training practices showed non-significant trends toward pain differences. Conclusions: Chronic wrist pain is common among handstand practitioners, particularly among younger athletes. These findings suggest that injury risk may relate more to training intensity and biomechanics than to simple training volume. Further research incorporating objective diagnostics and standardized intervention protocols is warranted. Full article

Objectives: This study compares My Jump Lab and VertVision apps for measuring vertical jump height in handball players, assessing their validity and reliability. The research assesses both apps’ accuracy, particularly concerning higher jumps, where errors have been noted, aiming to determine the most reliable tool. The goal is to provide a direct comparison between apps, as well as confirm the apps’ validity and reliability for handball players. Methods: The present research is a transversal observational study. Twenty-seven amateur athletes performed five jumps on a contact mat with simultaneous recording by a smartphone with a high-speed camera. Pearson’s r, ICC, SEM, CV, and Bland–Altman plots were used to evaluate discrepancies and determine accuracy. Results: Pearson correlation showed strong relationships, with ICC values between 0.993 and 0.998. Both apps overestimated jump height by 1.86% compared to the platform. Bland–Altman plots indicated minimal differences between observers, confirming high validity and reliability for CMJ measurement. Both apps demonstrated very high concurrent validity (r > 0.9) and reliability, with ICC values near 1 and CV below 5%. My Jump Lab exhibited smaller inter-observer differences, indicating greater consistency. Conclusions: The ease of use, affordability, and portability make both apps valuable for performance monitoring, training, and injury recovery. While both demonstrated good validity and reliability, My Jump Lab proved more consistent in jump comparisons. These tools extend beyond sports, supporting physiotherapy assessments and athletic training across diverse populations. Full article

The 4Rs of sports nutrition were proposed in recent years as an evidence-based framework to optimize post-exercise recovery within the context of allostasis. Under this paradigm, it is important to consider that each R represents a factor with a tremendous influence on the allostatic response and improves individual components of the allostatic load (AL), which will positively impact the exercise-induced adaptations and the athlete’s recovery. The 4Rs correspond to the following. (i) Rehydration—This is necessary to guarantee the post-exercise consumption of at least 150% of the body mass lost during the exercise accompanied by sodium (if faster replacement is required). (ii) Refuel—Carbohydrate intake (~1.2 g/kg body mass per hour for up to 4 h post-exercise) is essential not only in restoring glycogen reserves but also in supporting the energy needs of the immune system and facilitating tissue repair. Despite changes in substrate utilization, a ketogenic diet generally has neutral or negative effects on athletic performance compared to carbohydrate-rich diets. (iii) Repair—The ingestion of high-quality protein stimulates post-exercise net muscle protein anabolism and might contribute to faster tissue growth and repair. The use of certain supplements, such as creatine monohydrate, might help to enhance recovery, while tart cherry, omega-3 fatty acids, and dietary nitrate (e.g., Beta vulgaris, Amaranthus L.), as well as other herbal extracts containing flavonoid-rich polyphenols, deserve further clinical research. (iv) Recuperate—Pre-sleep nutrition (casein- or protein-rich meal with slow digestion rate) has a restorative effect, facilitating the recovery of the musculoskeletal, endocrine, immune, and nervous systems. In this article, we update the 4Rs framework, delve deeper into the allostasis paradigm, and offer theoretical foundations and practical recommendations (the 4Rs app) for the assessment of AL in athletes. We cautiously propose an AL index (AL_index) for physique competitors and elite athletes to evaluate the cumulative physiological stress induced by exercise and, thereby, to adjust exercise and nutrition interventions. Full article

Mixed Martial Arts (MMA) is a highly dynamic combat sport that requires precise motor coordination and technical execution. Video-based motion analysis, including two-dimensional (2D) and three-dimensional (3D) motion capture systems, plays a critical role in optimizing movement patterns, enhancing training efficiency, and reducing injury risk. However, the comparative validity of 2D and 3D systems for evaluating punching mechanics under external stressors remains unclear. This study aimed to first validate the measurement agreement between 2D and 3D motion analyses during sagittal-plane punches, and second, to examine the impact of fatigue and balance disruption on arm kinematics and punch dynamics in elite MMA athletes. Twenty-one male MMA fighters (mean age: 24.85 ± 7.24 years) performed standardized straight right punches (SRPs) and swing punches (SPs) under three experimental conditions: normal, balance-disrupted, and fatigued. Participants were instructed to deliver maximal-effort punches targeting a designated striking pad placed at a consistent height and distance. Each punch type was executed three times per condition. Kinematic data were collected using the my Dartfish Express(version 7.2.0) app (2D system) and MaxPRO infrared motion capture system (3D system). Statistical analyses included Pearson’s correlation coefficients, one-way analysis of variance (ANOVA), and linear mixed models (LMMs). Strong correlations (r = 0.964–0.999) and high intraclass correlation coefficient (ICC) values (0.81–0.99) confirmed the high reliability of 2D analysis for sagittal-plane techniques. Fatigue significantly decreased punch velocity and impact force (p < 0.01), while increasing joint angle variability (p < 0.01). These findings highlight the complementary use of 2D and 3D motion capture methods, supporting individualized monitoring, adaptive technique evaluation, and performance optimization in combat sports. Full article

The emergence of short video applications (“apps”) has facilitated the dissemination, inheritance, and protection of traditional sports and games (TSGs). However, the effectiveness of these apps in raising public awareness and responsibility toward the preservation and heritage of TSGs has received insufficient research attention. This study constructs a theoretical model based on value-belief-norm theory and the theory of planned behavior, employing both PLS-SEM and fsQCA methods to empirically analyze 417 questionnaires. The results indicate that the PLS-SEM method identifies key factors influencing users’ responsible behaviors toward TSGs on short video apps, along with the complex and interdependent relationships among these factors. The fsQCA method reveals the intricate interactions and nonlinear effects of the antecedents on users’ responsible behaviors and identifies six configurations that drive high-level TSG responsible behaviors among users. This paper extends research on public responsible behaviors concerning TSGs and provides important practical guidance for government managers, inheritors, and conservation entities in the protection and heritage of TSGs. Full article

Technological advances continually reduce the effort to digitally transform health-related activities such as rehabilitation and training. Exemplary systems use tracking and vital sign monitoring to assess physical condition and training progress. This paper presents a system for body stability training and coordination evaluation, using cost-efficient tracking and monitoring solutions. It implements the use case of app-guided back posture tracking on the ICAROS Pro training device via SteamVR Tracking 2.0, with pulse and respiration rate monitoring via Zephyr BioHarness 3.0. A longitudinal study on training effects with 20 subjects was conducted, involving a representative procedure created with a sports manager. Posture errors served as the main progress indicator, and pulse and respiration rates as co-indicators. Outcomes suggest the system’s capabilities to foster comprehension of effects and steering of exercises. Further, a secondary study presents a self-developed VR-based exergame demo for future system expansion. The Empatica EmbracePlus smartwatch was used as an alternative for vital sign acquisition. The user experiences of five subjects gathered via a survey highlight its motivating and entertaining character. For both the main and secondary studies, a thorough discussion elaborates on potentials and current limitations. The developed training system can serve as template and be adjusted for further use cases, and the exergame’s reception revealed prospective extension directions. Software components are available via GitHub. Full article

Background: Chronic health conditions frequently result in gait disturbances, impacting quality of life and mobility. Smartphone-based gait analysis has emerged as a promising alternative to traditional methods, offering accessibility, cost effectiveness, and portability. This systematic review evaluates smartphone-based inertial measurement units’ validity, reliability, and sensitivity for assessing gait parameters in individuals with chronic conditions. Methods: A comprehensive literature search in Web of Science, PubMed, Google Scholar, and SportDiscus identified 54 eligible studies. Results: Validity was evaluated in 70% of the included studies, with results showing moderate-to-strong associations between smartphone apps and gold-standard systems (e.g., Vicon), particularly for parameters such as gait speed and stride length (e.g., r = 0.42–0.97). However, variability was evident across studies depending on the health condition, measurement protocols, and device placement. Reliability, examined in only 27% of the included studies, displayed a similar trend, with intraclass correlation coefficients (ICCs) ranging from moderate (ICC = 0.53) to excellent (ICC = 0.95) for spatiotemporal parameters. Sensitivity and specificity metrics were explored in 41% and 35% of the included studies, respectively, with several applications achieving over 90% accuracy in detecting gait abnormalities. Feasibility was rated positively in 94% of the included studies, emphasising the practical advantages of smartphones in diverse settings. Conclusions: The findings of this systematic review endorse the clinical potential of smartphones for remote and real-world gait analysis, while highlighting the need for standardised methodologies. Future research should adopt a more comprehensive approach to psychometric evaluation, ensuring that reliability aspects are adequately explored. Additionally, long-term studies are needed to assess the effectiveness of smartphone-based technologies in supporting the personalised treatment and proactive management of chronic conditions. Full article

This study evaluated the validity and reliability of the Fitnessmeter mobile application for measuring change of direction (COD) performance compared to a gold-standard photocell system. Forty-six trained adolescent soccer players performed the 5 + 5 m COD test, with simultaneous data collection using the Fitnessmeter app and photocells. A strong correlation was observed between the two instruments (r = 0.971), with no significant differences in COD times (p > 0.05). Bland–Altman analysis indicated minimal systematic bias (0.02 ± 0.05 s) and acceptable limits of agreement. Reliability analysis demonstrated high consistency for both devices (Fitnessmeter ICC = 0.66–0.72; Photocells ICC = 0.57–0.76), with reproducibility confirmed by a low coefficient of variation values (<3%). The Fitnessmeter app also effectively measured inter-limb asymmetries, showing results comparable to photocells (p = 0.42). These findings validate Fitnessmeter as a reliable, portable, and cost-effective tool for COD assessment. Its accessibility makes it suitable for applications in sports, education, and rehabilitation, offering a practical alternative to expensive equipment. Further studies are recommended to confirm its reliability in other COD tests and contexts. Fitnessmeter’s innovative motion detection technology has the potential to democratize performance assessment, making it accessible to a broader audience beyond elite sports. Full article

Striking velocity is a key performance indicator in striking-based combat sports, such as boxing, Karate, and Taekwondo. This study aims to develop a low-cost, accelerometer-based system to measure kick and punch velocities in combat athletes. Utilizing a low-cost mobile phone in conjunction with the PhyPhox app, acceleration data was collected and analyzed using a custom algorithm. This involved strike segmentation and numerical integration to determine velocity. The system demonstrated moderate reliability (intraclass correlation coefficient (ICC) $3,1$ = $0.746$ to $0.786$, standard error of measurement (SEM) = $0.488$ to $0.921$ m/s), comparable to commercially available systems. Biological and technical variations, as well as test standardization issues, were acknowledged as factors influencing reliability. Despite a relatively low sampling frequency, the hardware and software showed potential for reliable measurement. The study highlights the importance of considering within-subject variability, hardware limitations, and the impact of noise in software algorithms. Average strike velocities exhibited higher reliability than peak velocities, making them a practical choice for performance tracking, although they may underestimate true peak performance. Future research should validate the system against gold-standard methods and determine the optimal sampling frequency to enhance measurement accuracy. Full article

Countermovement jump (CMJ) performance analysis is vital in sports science for assessing lower-body strength and neuromuscular efficiency. This study evaluated the validity of the Enode Sensor and My Jump 3 App for measuring vertical jump heights, comparing them to those measured using the established Force Plate. Twenty-nine participants performed CMJs measured using each device. Descriptive statistics indicated mean jump heights of 48.4 ± 4.18 cm (for the Enode Sensor), 47.3 ± 4.05 cm (for My Jump 3), and 46.1 ± 4.03 cm (for the Force Plate). Reliability was confirmed via Intraclass Correlation Coefficients (ICCs), with the Enode Sensor at 0.914 and My Jump 3 at 0.968, demonstrating excellent reliability. Bland–Altman analysis showed mean biases of 2.281 cm (for the Enode Sensor) and 1.297 cm (for My Jump 3) against the Force Plate, with limits of agreement suggesting close alignment. Strong positive correlations were observed (for the Enode Sensor, r = 0.972 and for My Jump 3, r = 0.987; p < 0.001), and linear regression analysis produced R² values of 0.945 and 0.973, respectively, confirming both tools’ accuracy for vertical jump measurement. These findings indicate that although both tools are suitable for CMJ assessment, My Jump 3 demonstrated slightly superior accuracy, underscoring the potential for accessible, reliable performance monitoring in sports contexts. Full article

Background: Quantitative pupillometry has been proposed as an objective means to diagnose acute sports-related concussion (SRC). Objective: To assess the diagnostic accuracy of a smartphone-based quantitative pupillometer in the acute diagnosis of SRC. Methods: Division I college football players had baseline pupillometry including pupillary light reflex (PLR) parameters of maximum resting diameter, minimum diameter after light stimulus, percent change in pupil diameter, latency of pupil constriction onset, mean constriction velocity, maximum constriction velocity, and mean dilation velocity using a smartphone-based app. When an SRC occurred, athletes had the smartphone pupillometry repeated as part of their concussion testing. All combinations of the seven PLR parameters were tested in machine learning binary classification models to determine the optimal combination for differentiating between non-concussed and concussed athletes. Results: 93 football athletes underwent baseline pupillometry testing. Among these athletes, 11 suffered future SRC and had pupillometry recordings repeated at the time of diagnosis. In the machine learning pupillometry analysis that used the synthetic minority oversampling technique to account for the significant class imbalance in our dataset, the best-performing model was a random forest algorithm with the combination of latency, maximum diameter, minimum diameter, mean constriction velocity, and maximum constriction velocity PLR parameters as feature inputs. This model produced 91% overall accuracy, 98% sensitivity, 84.2% specificity, area under the curve (AUC) of 0.91, and an F1 score of 91.6% in differentiating between baseline and SRC recordings. In the machine learning analysis prior to oversampling of our imbalanced dataset, the best-performing model was k-nearest neighbors using latency, maximum diameter, maximum constriction velocity, and mean dilation velocity to produce 82% accuracy, 40% sensitivity, 87% specificity, AUC of 0.64, and F1 score of 24%. Conclusions: Smartphone pupillometry in combination with machine learning may provide fast and objective SRC diagnosis in football athletes. Full article

As virtual reality (VR) sports training apps start to become more mainstream, it is important that human performance is measured from VR gameplay interaction data in a more meaningful way. CleanSheet is a VR training app that is played by over 100,000 users around the world. Many of those players are aspiring goalkeepers who want to use the app as a new way to train and improve their general goalkeeping performance. Whilst the leaderboards display how many shots players saved, these data do not take into account the difficulty of the shot faced. This study presents a regression model developed from a combination of existing expected goals (xG) models, goalkeeper performance metrics, and psychological research to produce a new shot difficulty metric called CSxG. Utilizing user save rate data as the target variable, a model was developed that incorporated three input variables relating to ball flight and in-goal positioning. Our analysis showed that the required rate of closure (RROC), adapted from Tau theory, was the most significant predictor of the proportion of goals conceded. A validation process evaluated the new xG model for CleanSheet by comparing its difficulty predictions against user performance data across players of varying skill levels. CSxG effectively predicted shot difficulty at the extremes but showed less accuracy for mid-range scores (0.4 to 0.8). Additional variables influencing shot difficulty, such as build-up play and goalpost size, were identified for future model enhancements. This research contributes to the advancement of predictive modeling in sports performance analysis, highlighting the potential for improved goalkeeper training and strategy development using VR technology. Full article

Measuring countermovement jump (CMJ) height accurately is essential for evaluating lower-body explosive power in athletes and other active populations. With technological advancements, various portable tools have been developed for this purpose, including force platforms, contact mats, and video-based software. This study aimed to (a) investigate the test–retest reliability of the KINVENT K-Deltas force platform for CMJ height measurement and (b) compare its accuracy with a contact mat (Chronojump, Spain) and a video-based software (My Jump app, version 3). Twenty-two physically active collegiate athletes (mean age of 19.7 ± 1.2 years) from various sports backgrounds completed five CMJ trials with simultaneous height measurements using all three tools. Intra-class correlation coefficients (ICC), Cronbach’s alpha, and coefficient of variation (CV) were calculated to assess reliability. In contrast, Pearson correlations and Bland–Altman plots were used to compare device results. The K-Deltas force platform exhibited high test–retest reliability (ICC = 0.981), closely matching the contact mat (ICC = 0.987) and the My Jump app (ICC = 0.986). Correlations between the instruments were strong (force platform vs. contact mat: r = 0.987; force platform vs. My Jump: r = 0.987; contact mat vs. My Jump: r = 0.996), with no between-instrument differences (t-test p = 0.203–0.935, effect size ≤ 0.01–0.16), demonstrating the interchangeability of these tools for practical purposes. However, Bland–Altman analysis revealed limits of agreement between the devices, indicating small but consistent measurement differences. While all instruments were reliable, discrepancies in the absolute values suggest practitioners should consider device-specific variations when comparing CMJ data. These findings highlight the reliability of the K-Deltas force platform as a viable alternative for measuring CMJ height, though differences between devices should be accounted for in applied settings. Therefore, the portable force plates can monitor training, predict injury risk, assess neuromuscular fatigue, and lead to informed decision-making. Full article