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BACKGROUND Physical inactivity is a major risk factor for noncommunicable diseases and the fourth leading cause of premature death worldwide. Nowadays, the World Health Organization (WHO) recommends performing at least 30 minutes of physical activity (PA) five times a week. However, these recommendations are independent on a person's age, gender or habits. In the field of sports performance, as well as in the clinical field, it is recognized that individualized training is more effective than general recommendations. OBJECTIVE We hypothesized that an automatic personalized training program based on some initial physical evaluations would increase overall quality of life, quality of sleep, and physical capabilities, as well as reducing fatigue and depression, better than the WHO’s recommendations. METHODS Our study was a 5-month randomized single-blinded controlled trial. One hundred and twelve sedentary or poorly active subjects were recruited and randomly split into two groups: personalized training (PT) or free training (FT). Physical capabilities and subjective measures such as quality of life, sleep, depression and fatigue were evaluated on both groups. After 1 month, both groups were asked to realize 150 minutes of PA per week for 4-months. To do so, PT group could either follow a “virtual coach” on a mobile application to follow some personalized PA or do what they would like to, while the FT group was to follow the general PA recommendations of WHO. RESULTS We did not find any group × time interaction for PA duration or intensity, physical qualities and subjective measures between PRE and POST. However, considering both groups together, there were a significant time effect between PRE and POST for duration of PA (18.2 vs 24.5 min/day of PA, p<0.001), intensity (2.36 vs 3.11, p<0.001) and workload (46.8 vs 80.5, p<0.001). Almost all physical qualities were increased between PRE and POST, i.e. estimated VO2max (26.8 vs 29 mL.min-1.kg-1, p<0.001), flexibility (25.9 vs 26.9 cm, p=0.049), lower limb isometric force’s (328 vs 347 Nm, p=0.002), reaction time (0.680 vs 0.633 s, p<0.001), power output on cyclo-ergometer (7.63 vs 7.82 W, p<0.003) and balance for left and right leg (215 vs 163 mm2, p<0.003 and 186 vs 162 mm2, p=0.048 respectively). Finally, still considering PT and FT group together, there were a significant improvement of the mental component of quality of life, well-being, depression and fatigue between PRE and POST. CONCLUSIONS The individualized training was not more effective than general recommendations. A slight increase of PA (from 18 to 24 min/day) in sedentary or poorly active people is enough to observe a significant increase of the physical capabilities and a significant improvement of the quality of life, well-being, depression and fatigue. CLINICALTRIAL NCT04998266

Assessing football players’ sprint mechanical outputs is key to the performance management process (e.g. talent identification, training, monitoring, return-to-sport). This is possible using linear sprint testing to derive force-velocity-power outputs (in laboratory or field settings), but (i) testing requires specific efforts and (ii) the movement assessed is not specific to the football playing tasks. This proof-of-concept short communication presents a method to derive the players’ individual acceleration-speed (AS) profile in-situ, i.e. from global positioning system data collected over several football sessions (without running specific tests). Briefly, raw speed data collected in 16 professional male football players over several training sessions were plotted, and for each 0.2 m/s increment in speed from 3 m/s up to the individual top-speed reached, maximal acceleration output was retained to generate a linear AS profile. Results showed highly linear AS profiles for all players (all R2&gt;0.984) which allowed to extrapolate the theoretical maximal speed and accelerations as the individual’s sprint maximal capacities. Good reliability was observed between AS profiles determined 2 weeks apart for the players tested, and further research should focus on deepening our understanding of these methodological features. Despite the need for further explorations (e.g. comparison with conceptually close force-velocity assessments that require, isolated and not football-specific linear sprint tests), this in-situ approach is promising and allows direct assessment of team sport players within their specific acceleration-speed tasks. This opens several perspectives in the performance and injury prevention fields, in football and other team sports, and the possibility to “test players without testing them”.