Otion (N = 30) and heart rate (HR; N = 60) analyses were performed throughout 10 official matches. The defined locomotor categories were standing still, walking, jogging, fast running, sprinting, backwards movement, sideways medium-intensity movement, and sideways high-intensity movement, and playing actions studied were jumps, shots, stops when preceded by high-intensity activities, changes of direction and one-on-one situations. During matches, the mean distances covered were 4,370 ± 702.0 m. Around 80% of the total time was spent standing still (43.0 ± 9.27%) and walking (35.0 ± 6.94%) and only 0.4 ± 0.31% with sprinting. The most frequent high-intensity actions were stops, changes of direction, and one-on-one situations. Effective mean HR was 157 ± 18.0 b·min−1 (82 ± 9.3% of HRmax), and total HR was 139 ± 31.9 b·min−1 (72 ± 16.7% of HRmax). The HR, time spent in high-intensity activities, frequency of stops, changes of direction, one-on-one situations, and most intense periods of the game were higher during the first half than during the second half (p ≤ 0.05). The opposite was observed for the number of time outs and the time between each change of activity (p = 0.00). Handball is an intermittent exercise that primarily uses aerobic metabolism, interspersed by high-intensity actions that greatly tax anaerobic metabolism. Additionally, exercise intensity decreases from the first to the second half of the match, suggesting that neuromuscular fatigue may occur during the game. The training of elite handball players should comprise exercises targeting the ability to perform specific high-intensity actions throughout the game and to rapidly recover during the less intense periods....

Adolescence is often viewed as a critical period for selection in youth soccer. The present study compared the characteristics of regionally selected and non-selected under-14 players (U-14) as a group and by position. Players were classified as local (n=69) and regional (n=45). Weight, height, skinfolds, functional capacities, soccer skills and goal orientation were measured and skeletal age was assessed with the Fels method. Factorial ANOVA was used to test the effect of selection, position and respective interaction terms, while discriminant analysis was used to identify the variables that contributed to selection. Selected players had an advanced maturity status (F=24.97, p<0.01), were heavier (F=30.67, p<0.01) and taller (F=35.07, p<0.01); performed better in explosive power (F=21.25, p<0.01), repeated sprints (F=20.04, p<0.01) and ball control (F=3.69, p<0.05); and were more ego oriented (F=13.29, p<0.01). The 2 competitive groups did not differ in agility, aerobic endurance, dribbling, shooting, passing, and task orientation. Position-related variation was negligible. The percentage of players who were correctly classified in the original groups was slightly lower when the analysis was performed for the total sample (86%) than by position (86–90%). Future research on talent identification and selection should adopt a multidimensional approach including variables related to the physiological, perceptual, cognitive and tactical demands.

The aims of the study were to (1) analyse the activity profile of youth football players during competitive matches, and (2) examine the relationship between physical match performance and intermittent exercise performance as well as . Thirty youth male football players, aged 14–17 years, carried out a laboratory treadmill test for determination of as well as the Yo‐Yo intermittent recovery level 1 (Yo‐Yo IR1) and Yo‐Yo intermittent endurance level 2 (Yo‐Yo IE2) tests. Time–motion analysis and heart rate (HR) recordings were performed during two competitive matches per player. Distance covered during the match was 6311±948 (range: 4435–8098) m, of which 12% were high‐intensity activities (HIA; 759±437 [374–2062] m), and 5% was backwards running (309±205 [12–776] m). Mean match HR was 168±12 (140–187) bpm, corresponding to 85% (69–91) of maximum HR. The total distance covered in the last 13.3‐min period of the match was 40%, 26% and 17% lower than in the first, second and fourth 13.3‐min periods of the match, respectively (P<0.05). The distance covered in backwards running decreased by 31% and 37% from the first to the last 13.3‐min periods of the first and second half, respectively (P<0.05). The Yo‐Yo IR1 was significantly associated with the time spent with sprinting during the match (r=0.63; P=0.002) and during the last 13.3‐min period (r=0.63; P=0.022). Both Yo‐Yo IR1 and Yo‐Yo IE2 were correlated with the time spent with match HIA (r=0.56 and r=0.57, respectively; P<0.05). No significant relationship was observed between and match time–motion variables (r=−0.13–0.25; P>0.05) or Yo‐Yo test performances (r=0.09–0.26; P>0.05). In conclusion, youth football players have a high heart‐rate loading during match play and a decreased running performance towards the end of the game. The intermittent exercise capacity, as determined in the Yo‐Yo IR1 test, appears to be a valid indicator of high‐intensity exercise performance in youth matches.

This study aimed to analyze changes in performance, muscle function, and stress-related biochemical markers in professional soccer players (n = 14) at 4 timepoints (3 for performance and 4 for stress-related biochemical markers) during the soccer season [ ] preseason (E1), midseason (E2), end of the season (E3) [ ] and after the end of the recovery period (E4). Performance in 5- and 30-m sprints, countermovement jump, and agility, and maximal isokinetic knee extension and knee flexion strength were measured (E1 to E3). We observed increased in-season levels of myoglobin (E2 > E1 and E4; p < 0.05), a higher testosterone/cortisol ratio (T/C), and increased levels of creatine kinase (CK), C-reactive protein, superoxide dismutase (SOD), protein sulfhydryls (–SH), and malondialdehyde (E2 and E3 > E1 and E4; p < 0.05). Lower cortisol concentrations (E3 < E1 and E4; p < 0.05) and glutathione reductase activity (E3 < E2 and E4; p < 0.05) were observed at the end of the season. T/C, CK, SOD, –SH, and malondialdehyde decreased during the off-season, and cortisol and glutathione reductase increased (E3 < E4; p < 0.05). Agility increased in E2 and E3 (p < 0.01). Significant correlations were found during the season between hormonal and muscle function parameters (r = 0.56–0.86; p < 0.05). In addition, in E2, significant associations were observed between match-accumulated time (MAT_E2; minutes played by each player during the competition period), performance, and hormonal and redox parameters (r = 0.456–0.615; p < 0.05). In conclusion, this study shows that soccer players face significant changes in biomarkers of physiologic strain (muscle damage and oxidative stress-related markers) during the season, but values return to normal during the off-season. Additionally, MAT influences physical, hormonal, and oxidative stress-related parameters in professional soccer players.