The aim of the current study is to quantify oxygen uptake, heart rate and molecular responses of human skeletal muscle associated with mitochondrial biogenesis following an acute bout of simulated soccer training.Muscle biopsies (vastus lateralis) were obtained from nine active men immediately pre-, post-and 3 h post-completion of a laboratory-based soccer-specific training simulation (LSSTS) on a motorised treadmill.The LSSTS was a similar intensity (55 ± 6% V O2max) and duration (60-min) as that observed in professional soccer training (e.g. standing 41%, walking 37%, jogging 11%, high-speed running 9% and sprinting 2%). Post-exercise, muscle glycogen decreased (Pre; 397 ± 86 mmol•kg -1 dw, Post; 344 ± 64 mmol•kg -1 dw; P = 0.03), plasma lactate increased (P < 0.001) up to ~4-5 mmol.L -1 , NEFA and glycerol increased (P < 0.001) to values of 0.6 ± 0.2 mmol.L -1 and 145 ± 54 μmol.L -1 , respectively.PGC-1α mRNA increased (P = 0.009) 5-fold 3 h post-exercise.We provide novel data by demonstrating that soccer-specific training is associated with increases in PGC-1α mRNA. These data may have implications for practitioners in better understanding the specific 'muscle' responses to soccer-specific training protocols in the field.

The purpose of this study was to identify the frequency and characteristics of injuries that occurred during the training camps and matches of the national soccer teams (under-20 [U-20], under-23 [U-23], A men's national teams). The research data were based on injuries that occurred from January 2016 to December 2017. The athletic trainer, a member of the Korea Football Association, recorded injuries based on the recording sheet of the Asian Football Confederation Daily Medical Report. A total of 1,689 (984 in 2014; 705 in 2017) injuries were reported for the 2 years. Most injuries were sports injuries (95%, sprains, etc.), and other conditions such as respiratory, digestive, and ocular, comprised only 5% of cases. The most injured areas of the national team players were the lower limbs (85%, 1,366). The frequency of the head/trunk and upper extremity injuries were relatively low (8.4%, 135; 6.5%, 105). The frequency of injuries according to positions were as follows: midfielder (40.3%, 648), defender (36.6%, 688), forward (17.8%, 286), and goalkeeper (5.2%, 84). The most common types of injuries were contusions (37.3%, 599), followed by muscle rigidity (29.0%, 466) and sprains (16.8%, 270). The characteristics of injuries amongst national soccer teams, according to age, were similar, but the injury characteristics for each position were different. Therefore, when organizing training programs for prevention and rehabilitation of athlete injuries and improvement of performance, it is necessary to consider the performance characteristics of each position.

There may be an optimal period of time to maximize the improvement of physical fitness during adolescence. The aim of this study was to examine the magnitude of changes in physical fitness after 8 weeks of preseason training according to chronological ages after the age at peak high velocity. Thirty male young football players from an elite football team (U-16, n= 10; U-17, n= 10; U-18, n= 10) participated in the study. The players completed an 8-week general preseason football training and participated in the pre-and posttests to measure physical fitness. The 8-week preseason training improved the power of all young players (P < 0.05). The 20-m sprint performance was improved by training in U-16 and U-18 (P< 0.05), but no changes were found in the U-17 group (P> 0.05). Significant differences were found in the arrowhead left in U-16 and U-18 (P< 0.05) after training; however, no difference was observed in U-17 (P> 0.05). Coordination was enhanced further in U-16 and U-17 (P< 0.05) compared with that in U-18 (P> 0.05). The performance of repeated sprints and Yo-Yo intermittent recovery test level 1 (Yo-Yo IR1) were similar between pre-and posttraining in all age groups (P> 0.05). Collectively, the results emphasized the importance of systematic and scientific training methods to improve the fitness levels of young football players in the preseason training period. Moreover, training to improve coordination in young football players is effective at younger ages.

Exercise training involving exercises of optimal intensity and duration improves psychological and medical variables in relative leisure-deprived people living with HIV/AIDS. This study aimed to analyze associated psychological variables and the effect of exercise intensity and duration on immune responses in relative leisure-deprived people infected with HIV. The participants completed different moderate-intensity exercises (30 min (60–80% HRmax) and 45 min (60–80% HRmax)) and high-intensity exercise for 10 min (>80% HRmax). Levels higher than “normal” were rated for relative leisure deprivation, indicating relative deprivation of leisure among participants. The overall level of quality of life was “normal”, indicating that quality of life was not considered high. The stress level was psychologically considered low. Time had a significant effect on cortisol levels (p < 0.05). Compared to pre-exercise, cortisol level was significantly decreased immediately after moderate exercise for 45 min and 3 h post-exercise after high-intensity exercise for 10 min (p < 0.05). However, time and the interaction of condition and time had no significant effect on IL-6 and sIgA levels (p > 0.05). Despite the small sample size of this pilot study, the results demonstrate that moderate-intensity exercise can be recommended to improve the health and quality of life of people infected with HIV.

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