Heart rate variability (HRV) has been proposed as a useful marker that can show the performance adaptation and optimize the training process in elite athletes. The development of wearable technology permits the measurement of this marker through smartphone applications. The purpose of this study is to assess the validity and reliability of short and ultra-short HRV measurements in elite cyclists using different smartphone applications. Twenty-six professional cyclists were measured at rest in supine and in seated positions through the simultaneous use of an electrocardiogram and two different smartphone applications that implement different technologies to measure HRV: Elite HRV (with a chest strap) and Welltory (photoplethysmography). Level of significance was set at p < 0.05. Compared to an electrocardiogram, Elite HRV and Welltory showed no differences neither in supine nor in seated positions (p > 0.05) and they showed very strong to almost perfect correlation levels (r = 0.77 to 0.94). Furthermore, no differences were found between short (5 min) and ultra-short (1 min) length measurements. Intraclass correlation coefficient showed good to excellent reliability and the standard error of measurement remained lower than 6%. Both smartphone applications can be implemented to monitor HRV using short- and ultra-short length measurements in elite endurance athletes.

Purpose: The talent identification and selection process in young male soccer players is mainly focused on anthropometrics and physical performance, but social factors are also considered in this process. The purpose of this study was to test the existence of the relative age effect and its possible influence on anthropometrics and physical performance and to analyze coaches’ efficacy expectations. Method: Data for 564 young male soccer players (M_age = 13.7 ± 1.5 years; M_weight = 53.7 ± 11.6 kg; M_height = 160.2 ± 11.6 cm) included their birth quartile, maturity status, anthropometrics, a physical test battery, and coaches’ efficacy expectations. Results: Early-born players were overrepresented (p < .05). Early-born players were not statistically taller, heavier, or better at physical performance (p > .05) when maturation and chronological age were controlled as confounding factors. However, coaches expected more from early-born players (p < .05), and the inferential analysis showed likely to very likely worthwhile differences between the coaches’ expectations for players born in the first quartile of the year and those born in the fourth quartile of the year. Conclusions: Anthropometrical and physical performance variables were not affected by birth quartile, and coaches’ efficacy expectations were related to the relative age effect.

Strength training is crucial for soccer players’ long-term development at early ages and the biological maturation may influence specific strength-training adaptations. The aim of this study was to propose a strength-training programme for the strength development of pre-pubertal players and to analyse the adaptations to this training programme in players with different maturity status. One hundred and thirty young male soccer players participated in an 8-week strength-training programme consisting of two sessions per week (20-minutes of a combination of plyometric and resistance exercises) which was conducted prior to their normal soccer training. Three maturity groups were defined according to the years from/to their peak height velocity (PHV) as Pre-, Mid- and Post-PHV. Initial differences between the maturity groups were found in anthropometrical (weight and height) and physical performance variables (One Repetition Maximum (RM), Peak Power output (PP), 30-m sprint and T-test). The strength-training programme was beneficial for the three maturity groups (p< 0.05) with general greater improvements for the Pre- and Mid-PHV groups, with large effects in RM, PP and T-test, than for the Post-PHV group (moderate effects). The strength-training programme proposed in the present study seems to be positive for the strength-related development in young soccer players especially for Pre- and Mid-PHV players. The differences in the training adaptations for players with different maturity status suggest the individualization of the training stimulus for the correct long-term development of the players.

The aims of this study were to report the relative age effect in different competitive levels and field positions and to analyse the differences within and between different competitive levels and field positions. Data for 203 young soccer players (14.2 ± 1.1 years) included anthropometrics and physical performance (Countermovement jump [CMJ], 30-m sprint, T-test and Yo-Yo IR1). Their competitive level and their field position were registered. The percentage of relative older players (1^stHY) was higher in the better competitive levels (L1: 80.6%, p <.001; L2: 68.2%, p <.001 and L3: 58.5%, p <.01), but it was similar between field positions (DF: 68.1%, p <.001; MF: 69.6%, p <.001 and FW: 67.2%, p <.001). Anthropometrical and physical performance differences were found between players of different competitive levels but not between relative older and younger players in each competitive level and field position. The relative age effect is higher in the better competitive levels. Anthropometrical and physical performance differences between players are not due to the relative age but to the level of competition. Relatively older players do not seem to be more likely to be selected for specific field positions. The causes of relative age effect need more research.

Talent identification and selection process in young football is based on coaches’ decisions regarding the players’ performance at early ages. The aim of this study was to show how the maturity status and the relative age impact on young football players’ physical performance and their coaches’ efficacy expectations. The physical performance (1RM, Peak power output [PPO], 30-m sprint and t-test) of 118 young football players (U13 to U15; and their coaches’ efficacy expectations were assessed. Relative age was calculated according to the players’ date of birth within their selection year. The maturity status was estimated as the years from/to their peak height velocity (PHV). Linear regression analyses showed a significant relationship between players’ physical performance and their maturity status but not with their relative age. In contrast, the maturity status of players only was associated to the coaches’ efficacy expectations in the 1RM and PPO tests, whereas the relative age was a predictor of the coaches’ expectations about players’ performance in the t-test. These findings may be important for coaches and managers in young football academies since inter-individual differences in the maturity status but not in the relative age are related to physical performance despite the coaches’ expectations.

Physical exercise has emerged as a promising complementary intervention for individuals with substance use disorders (SUD). This comprehensive review examines the neurobiological, psychological, and social benefits of exercise in improving quality of life (QOL), mental health, sleep quality, craving, physical fitness, and cognitive function among individuals with SUD. Aerobic exercises, particularly those of moderate intensity, demonstrate a consistent efficacy in reducing anxiety, depression, and cravings, while also enhancing cardiovascular health and psychosocial well-being. Strength training and concurrent programs provide additional benefits for muscular and cognitive function, although their effects on mental health are less consistent. Mind–body disciplines like yoga and Tai Chi offer accessible entry points for individuals with low baseline fitness but exhibit variable outcomes, especially in sleep and craving management. High-intensity interval training (HIIT) shows potential for craving reduction and cardiovascular improvements but may pose challenges for individuals with low initial fitness. This review underscores the importance of tailored, well-structured programs that align with participants’ needs and capabilities. Future research should prioritize standardizing protocols, incorporating technological tools, and exploring hybrid intervention models to maximize adherence and therapeutic impact. Physical exercise remains a vital, multifaceted tool in comprehensive SUD rehabilitation strategies.