The purpose of this study was to compare the effects of Small-Sided Games (SSG) vs. Interval Training (IT) in soccer training on aerobic fitness and physical enjoyment in youth elite soccer players during the last 8 weeks of the season. Seventeen U-16 male soccer players (age = 15.5 ± 0.6 years, and 8.5 years of experience) of a Spanish First Division club academy were randomized to 2 different groups for 6 weeks: SSG group (n = 9) and IT group (n = 8). In addition to the usual technical and tactical sessions and competitive games, the SSG group performed 11 sessions with different SSGs, whereas the IT group performed the same number of sessions of IT. Players were tested before and after the 6-week training intervention with a continuous maximal multistage running field test and the counter movement jump test (CMJ). At the end of the study, players answered the physical activity enjoyment scale (PACES). During the study, heart rate (HR) and session perceived effort (sRPE) were assessed. SSGs were as effective as IT in maintaining the aerobic fitness in elite young soccer players during the last weeks of the season. Players in the SSG group declared a greater physical enjoyment than IT (P = 0.006; ES = 1.86 ± 1.07). Coaches could use SSG training during the last weeks of the season as an option without fear of losing aerobic fitness while promoting high physical enjoyment.

The aim of this study was to examine the intrasubject (intraclass coefficient correlation [ICC]) and intersubject variability (coefficient of variation [CV]) of soccer ball drills (BD) involving or not opposition in male youth soccer. For this purpose, a collective ball dribbling (DB) exercise and a 7-a-side ball game without coach encouragements were considered. Exercise intensity was assessed as heart rate (HR), training load (TL), and perceived exertion scales. Fourteen U-14 male soccer players (age, 14.79 ± 0.43 years and experience, 6.5 years) of a Spanish First Division club academy participated in the study. Ball drills were examined for variability over 5 successive training sessions in similar field conditions. Results showed that 7-a-side was significantly (p = 0.000) more demanding than DB. Indeed the TL, HRmax, HRmean, overall perceived exertion, and leg muscular perceived exertion (MPE) resulted 141, 8.7, 11, 56, and 72%, higher in 7-a-side than in DB, respectively. In the 7-a-side condition, good intersubject (CV < 10%) and low intrasubject (ICC < 0.7) variability were observed. In the DB condition, CVs were below 10% CV only for HR variables and the ICC values were higher than 0.7 only for MPE. Despite the moderate reproducibility of BD not considering opponents, this condition did not reveal to induce homogeneous physiological responses in young soccer players. Therefore, the use of this kind of drills may be questionable when considered as alternative of moderate intensity generic aerobic training. Despite the higher interaction between players variability in the opposition drills resulted lower, this suggests their use as a specific conditioning exercise.

The aim of the present study was to analyze the effect of block (BP) and a reverse training periodization (RP) in the hematological and running performance of amateur trained athletes. Modifications in hematological, aerobic, and anaerobic running performance and countermovement jump before and after twelve weeks of BP vs. RP training programs were analyzed in 16 trained athletes (eight males: 40.0 ± 6.2 years; 179.2 ± 12.8 cm; 73.8 ± 12.2 kg; and eight females: 34.2 ± 4.1 years; 163.4 ± 9.6 cm; 57.0 ± 11.0 kg). A significant decrease in heart rate (HR) at ventilatory threshold (VT1) (p = 0.031; ES = 1.40) was observed in RP without changes in BP. In addition, RP increased significantly VO2max (p = 0.004; ES = 0.47), speed at VO2max (p = 0.001; ES = 1.07), HR at VT2 (p < 0.001; ES = 1.32) and VT1 (p = 0.046; ES = 0.57), while BP improved VO2max (p = 0.004; ES = 0.51), speed at VO2max (p = 0.016; ES = 0.92), and HR at VT2 (p = 0.023; ES = 0.78). In addition, only RP increased anaerobic performance in a running-based anaerobic sprint test (RAST) (mean sprint: p = 0.009; ES = 0.40, best sprint: p = 0.019; ES = 0.30 and total time: p = 0.009; ES = 0.40). Moreover, both types of training periodization proposed in this study maintained hematological values and efficiently improved jump performance (p = 0.044; ES = 0.6) in RP and p = 0.001; ES = 0.75 in BP). Therefore, twelve weeks of either RP or BP is an effective strategy to increase jump and aerobic running performance maintaining hematological values, but only RP increases anaerobic running performance.

The main aim of this study was to examine the association between the Maximal Aerobic Speed (MAS) measured by the Université de Montréal Track Test (UM-TT) and on a running treadmill test in young elite soccer players.