Effects of soccer training on health-related physical fitness measures in male adolescents.

PURPOSE: The aims of this study were to (1) investigate the health-related physical fitness profile of untrained adolescent boys in comparison to adolescent soccer players, (2) determine the intensity and enjoyment of 6 v 6 and 4 v 4 small-sided games, and (3) evaluate the health-related effects of a short-period of soccer training in the untrained group. METHODS: Forty-one adolescent boys (untrained, n = 24: age = 15.9 ± 0.6 years; trained, n = 17: age = 15.7 ± 0.7 years) were recruited. For Purpose 1, the players (n = 17) and the untrained (n = 24) boys were tested for speed, jumping power, postural balance, flexibility, and aerobic capacity. After baseline testing, Purposes 2 and 3 were addressed by randomly assigning the untrained boys to either a soccer-training group (small-sided games, 2 sessions per week for 8 weeks) or to a control group, followed by identical retesting. RESULTS: At baseline, physical fitness was higher (p < 0.001) in trained players than in untrained for aerobic fitness, sprinting, jumping power, and postural balance. Small-sided games using 6 v 6 or 4 v 4 elicited similar heart rate (HR) (mean: ~ 85% peak heart rate, HRpeak), rate of perceived exertion, and enjoyment responses. Over 8 weeks, the between-group analysis revealed that soccer training had a large beneficial effect on postural balance (45%) when compared with control group with unclear effects on other fitness parameters. CONCLUSION: Adolescent soccer players had markedly higher physical fitness compared with untrained adolescents. Small-sided soccer games practiced by untrained adolescents elicited high exercise intensity. While 8 weeks of twice-weekly soccer training sessions induced significant improvement in postural balance, the short duration of the study was not sufficient to result in between-group differences in sprint and jump performance or aerobic fitness.

Cardiac parasympathetic reactivation after small-sided soccer games and repeated sprints in untrained healthy adolescents.

BACKGROUND: It has been shown that recreational soccer was a highly motivating and social activity which produces large improvements in health-related indices in sedentary healthy and unhealthy subjects. The purpose of this study was to compare the acute parasympathetic reactivation after small-sided soccer games (SSG) and repeated sprints training (RST) sessions. METHODS: Eight post-pubertal untrained adolescents (age 15.8±0.6 years, body mass 59.1±3.7 kg, height 1.7±0.1 m) performed a RST, SSG and a control session in a counterbalanced order. Heart rate variability (HRV) indices in time and frequency domain, heart rate recovery and rating of perceived exertion (RPE) were evaluated. RESULTS: RPE was significantly lower after SSG compared with RST (P=0.02, ES=1.1). There was a significant decrease in mean R-R intervals after RST (difference: -19.6%, P<0.01, ES=1.7) and after SSG (-19.2%, P<0.01, ES=2.3). A significant decrease was also noted in SDNN after RST (-26.6%, P=0.02, ES=1.8) and SSG (-37.8%, P=0.01, ES=1.1). For RMSSD, a significant decrease was observed only after SSG (48%, P=0.01, ES=1.3). No significant change in all HRV indices after the control condition. CONCLUSIONS: SSG and RST elicited high and similar heart rates responses. A low parasympathetic reactivation during early recovery was noted after both RST and SSG. These results were important especially for clinician looking to prescribe repeated sprint or small-sided game for sedentary subjects.

Jumping improves lower limbs bone mass and lean mass in elite jumpers.

BACKGROUND: The present study was designed to examine the influence of extreme impact loading induced by jump training on bone mineral density (BMD) and bone mineral content (BMC) in high level jumpers. METHODS: Forty boys volunteered for the study aged 20 to 21 years. They were 22 high level jumpers and 18 controls. Bone mass and body composition measurements were performed by dual-energy X-ray absorptiometry, in the total body and at different sites. RESULTS: The results showed that BMC, BMD, bone area, and lean mass (P<0.0001) were significantly higher in the jumpers compared to the controls. A strong positive correlation was found between lean mass and bone parameters (BMC at the right femur, r=0.80; P<0.01). The values of the same correlation were weak in the control group. In addition, the effects of the regular practice of jumping on the BMD, BMC, and bone area were more pronounced in the lower limbs (P<0.01). These adaptations were site-specific, with increased bone mass at the lower limbs (P<0.01), especially at the legs, right and left leg (LRL) (P<0.05). It appears that the time dedicated to this activity may be account for the difference between jumpers and controls. CONCLUSIONS: The practice of high level jump starting at pubertal age generates an increase and an acquisition of the bone mass in males. This adaptation is further enhanced by the times dedicated for this activity. Therefore, it would be interesting to program jumping activities daily to conserve bone mineral and to prevent osteopenia.

Antioxidant status and oxidative stress at rest and in response to acute exercise in judokas and sedentary men.

It is well recognized that acute strenuous exercise is accompanied by an increase in free-radical production and subsequent oxidative stress, in addition to changes in blood antioxidant status. Chronic exercise provides protection against exercise-induced oxidative stress by upregulating endogenous antioxidant defense systems. Little is known regarding the protective effect afforded by judo exercise. Therefore, we determined antioxidant and oxidative stress biomarkers at rest and in response to acute exercise in 10 competitive judokas and 10 sedentary subjects after mixed exercise (anaerobic followed by aerobic). The subjects performed a Wingate test, followed by 30 minutes of aerobic exercise performed at 60% of maximal aerobic power. Blood samples were taken, by an intravenous catheter, at rest (R), immediately after the physical exercise (P0), and at 5 (P5), 10 (P10), and 20 (P20) minutes postexercise. The measured parameters included the activity of the antioxidant enzymes superoxide dismutase, glutathione peroxidase, and glutathione reductase, in addition to α-tocopherol, and total antioxidant status. Malondialdehyde was measured as a representation of lipid peroxidation. At rest, the judokas had higher values for all antioxidant and oxidative stress markers as compared to the sedentary subjects (p < 0.05). Plasma concentrations of all parameters except for α-tocopherol increased significantly above resting values for both the judokas and sedentary subjects (p < 0.05) and remained elevated at 20 minutes postexercise. A significant postexercise decrease was observed for α-tocopherol (p < 0.05) at P20 for judokas and at P5 for sedentary subjects. These data indicate that competitive judo athletes have higher endogenous antioxidant protection compared to sedentary subjects. However, both groups of subjects experience an increase in exercise-induced oxidative stress that is not different.

Blood metabolites during basketball competitions.

This study examined basketball game blood hormonal and metabolite responses in 38 (8 guards, 18 forwards, and 12 centers) male national elite-junior players (age, 18.2 +/- 0.5 years; height, 1.89 +/- 0.1 m; body mass, 80.3 +/- 6.7 kg; body fat, 8.2 +/- 5.6%; maximum oxygen uptake Vo2max], 52.8 +/- 2.4 mlxkgxmin). At the moment of the investigation, players had 8 +/- 1.6 years of competitive experience. Blood samples were collected at the beginning, at halftime, and at fulltime of 6 junior competitive games (Tunisian under 19 basketball championship). Game intensity was assessed monitoring heart rates (HR). During the game, players attained 93 +/- 2% of maximal HR. Triglycerides (TG) and free fatty acids (FFA) concentrations significantly increased during the game, most markedly so in the second half. Postgame TG and FFA concentrations were significantly (p < 0.05 and p < 0.001, respectively) lower for guards (1.48 +/- 0.22 and 0.88 +/- 0.14 mmolxL, respectively) than for centers (1.88 +/- 0.30 and 1.08 +/- 0.09 mmolxL, respectively). Plasma glucose significantly increased at halftime (from 4.05 +/- 1.27 to 5.98 +/- 0.88 mmolxL; p < 0.001) but decreased in the second half. Serum insulin (INS) progressively decreased for all players during the game, whereas serum cortisol increased at the end of the first half (from 333 +/- 129 to 487 +/- 209 nmolxL; p < 0.001) to remain increased throughout the second half.Basketball game demands seem to induce significant metabolic-hormonal changes on players. Higher values of HR and glycemia were observed in the first half, but a more important increase of lipolytic variables was recorded in the second half. Changes in metabolic markers are role-dependent.

One-year endurance training: effects on lung function and airway inflammation.

The aim of this study was to determine whether endurance training in athletes induces airway inflammation and pulmonary function disorders. Respiratory pattern and function were analysed in ten healthy endurance runners at rest, during sub-maximal exercise, and during the recovery. Inflammatory cells and metabolites (histamine, interleukin-8, and leukotriene E(4)) were measured in sputum at rest and after exercise. The experiments were conducted on three different occasions (basic endurance training, pre-competitive and competitive periods). In spite of the absence of post-exercise spirometric changes and respiratory symptoms, airway cells counts and inflammatory markers changed significantly. At the beginning of the experiment, athletes' induced sputum showed an abundance of macrophages compared with neutrophils. We found a high percentage of neutrophils during the pre-competitive and competitive periods of the sport season (41% and 37%), a significant increase in macrophage counts during the pre-competitive period (51%), and a significant rise in total cells, interleukin-8, leukotriene E(4), and histamine during the competitive period. In conclusion, one year's training increased markers of inflammation in the airways of endurance runners without symptoms or changes in pulmonary function, suggesting that airway inflammation is of insufficient magnitude to markedly impact lung function in healthy athletes.