Effects of 3 hours a week of physical activity on body fat and cardio-respiratory parameters in obese boys

The prevalence of overweight or fat children and adolescents has markedly increased in Hungary during the past three decades. Among the possible factors insufficient physical activity and a relative or absolute excess of calorie intake associated to it can be regarded as the most important ones. The aim of the study was to analyse the effects of a 20-week aerobic exercise on body composition and on the exercise tested cardio-respiratory functions in 10-year-old obese boys. Obesity was defined by a BMI greater than the cut-off value reported by Cole and co-workers (5) and a relative body fat content above 30% (13). Of the study group 21 volunteer children completed the program; the contrast group contained 28 obese boys. Mean calendar age was 10.03 +/- 0.26 in the study group (S) and 9.88 +/- 0.29 in the control group (C). The members of group S had two curricular physical education (PE) classes a week and three extracurricular aerobic physical activity sessions of 60 min net time in the afternoon, on Mondays (swimming and water games), Wednesdays (folk dance) and Fridays (soccer). Group C had only 2 PE classes a week. Anthropometric and spiroergometric data were collected in the middle of January and June of 2004. Relative body fat content and BMI did not increase during the observation period in contrast to the significant increase of both in the control group. Peak minute ventilation, aerobic power, oxygen pulse, and running distance (performed on a treadmill) increased in group S, and did not change in group C. The program was considered successful despite that the changes in the observed physiological and physical indicators appeared to be slight. However, the 5-month elevated level of physical activity brought about such development in the physical status of the obese subjects that might be an appropriate basis for regular training. Fortunately, the cardio-respiratory functions of the investigated boys were not affected yet by obesity, consequently the really dramatic change in their further lifestyle exclusively depends on their decision.     

Incompatibility of endurance- and strength-training modes of exercise

Twenty-two male and female subjects trained for 7 wk for endurance (group E), for strength (group IS), or for both strength and endurance (group C) to evaluate the effect of concurrent performance of both modes of training on the in vivo force-velocity relationship of human muscle and on aerobic power. Endurance training consisted of five 5-min sessions three times a week on cycle ergometer with a work load that approached the subject's peak cycle-ergometer O2 uptake (peak CE VO2). Strength training consisted of two 30-s sets of maximal knee extensions per day performed on an isokinetic dynamometer three times a week at a velocity of 4.19 rad X s-1. Group C performed the same training as groups IS and E, alternating days of strength and endurance training. Subjects (groups C and IS) were tested pre- and posttraining for maximal knee-extension torque at a specific joint angle (0.52 rad below horizontal) for seven specific angular velocities (0, 0.84, 1.68, 2.81, 3.35, 4.19, and 5.03 rad X s-1). Groups C and E were tested for peak CE VO2 pretraining, at 14-day intervals, and posttraining. Group IS showed significant increases in angle-specific maximal torque at velocities up to and including the training speed (4.19 rad X s-1). Group C showed increases (P less than 0.05) at velocities of 0, 0.84, and 1.68 rad X s-1 only. Peak CE VO2, when expressed in relative or absolute terms, increased (P less than 0.05) approximately 18% for both groups E and C.(ABSTRACT TRUNCATED AT 250 WORDS)     

Anthropometric indices and physical fitness in university undergraduates with different physical activity.

Physical activity and fitness have important health promoting effects with respect to arterosclerosis and coronary heart disease in particular. An intervention study of physical status and physical activity in university undergraduates (University of Tartu) has been carried out. The physically inactive (Group I) consisted of 310 undergraduates (235 females and 75 males) of the Faculty of Medicine. The physically active (Group II) was recruited from among undergraduates (22 females and 23 males) of the Faculty of Exercise and Sport Sciences, who participated in training sessions regularly, 3 to 5 times per week. Anthropometric body measurements, arm force, vital capacity and exercise test on the bicycle ergometer (PWC170) were performed. There were no statistically significant differences between the mean values of anthropometric indices in case of physically inactive and physically active female subjects. In the group of physically active male undergraduates, weight and shoulder width were larger than in students with physically sedentary life style (p < 0.05). Most of the female and male students had normal BMI. There were statistically significant differences in the mean values of vital capacity, arm force and aerobic working capacity between the study groups, while physically active students had higher physical capacity (p < 0.001). Mean anthropometric indices demonstrated a statistically significant increase in both female and male university undergraduates after the interval of 30 years. Normal BMI and anthropometric indices do not serve a as guarantee of physical fitness for university undergraduates who are involved in sedentary life style. Regular physical activity has a strong positive impact on physical fitness, particularly on aerobic capacity which is the most important health promoting component of physical fitness with respect to coronary heart disease.     

Physical Training Improves Body Composition of Black Obese 7- to 11-Year-Old Girls

We determined the effect of supervised physical training, without dietary intervention, on body composition of obese girls. The subjects were 25 obese 7-to 11-year-old black girls, divided into physical training and lifestyle education groups which were comparable on baseline body composition; 22 girls finished all aspects of the study. Twelve girls engaged in aerobic training (10 weeks, 5 days/week) while 10 engaged in weekly lifestyle discussions without formal physical training. Total body and regional body composition were measured with dual energy x-ray absorptiometry, skin folds and circumferences. Aerobic fitness was measured by heart rate response to sub maximal treadmill exercise. The physical training group attended 94% of scheduled sessions and kept their heart rates at an average of 163 bpm for 28 minutes/session. The lifestyle group attended 95% of their sessions; they remained stable in aerobic fitness and most body composition measurements. The physical training group showed a significant improvement in aerobic fitness and a significant decline of 1.4% body fat. Skin fold and circumference indices of fatness also declined significantly in physical training, without dietary intervention, improved the fitness and body composition of obese black girls.     

Short-term effects of strength and plyometric training on sprint and jump performance in professional soccer players

The purpose of this study was to compare the effects of combined strength and plyometric training with strength training alone on power-related measurements in professional soccer players. Subjects in the intervention team were randomly divided into 2 groups. Group ST (n = 6) performed heavy strength training twice a week for 7 weeks in addition to 6 to 8 soccer sessions a week. Group ST+P (n = 8) performed a plyometric training program in addition to the same training as the ST group. The control group (n = 7) performed 6 to 8 soccer sessions a week. Pretests and posttests were 1 repetition maximum (1RM) half squat, countermovement jump (CMJ), squat jump (SJ), 4-bounce test (4BT), peak power in half squat with 20 kg, 35 kg, and 50 kg (PP20, PP35, and PP50, respectively), sprint acceleration, peak sprint velocity, and total time on 40-m sprint. There were no significant differences between the ST+P group and ST group. Thus, the groups were pooled into 1 intervention group. The intervention group significantly improved in all measurements except CMJ, while the control group showed significant improvements only in PP20. There was a significant difference in relative improvement between the intervention group and control group in 1RM half squat, 4BT, and SJ. However, a significant difference between groups was not observed in PP20, PP35, sprint acceleration, peak sprinting velocity, and total time on 40-m sprint. The results suggest that there are no significant performance-enhancing effects of combining strength and plyometric training in professional soccer players concurrently performing 6 to 8 soccer sessions a week compared to strength training alone. However, heavy strength training leads to significant gains in strength and power-related measurements in professional soccer players.     

Effects of a low-intensity conditioning programme on V˙O2max and maximal instantaneous peak power in elderly women

The effects of 12 weeks of a low-intensity general conditioning programme on maximal instantaneous peak power (Wpeak) and maximal oxygen uptake (VO2max) were examined in 20 elderly women. After medical, familiarisation, and ethical procedures, the subjects were randomly divided into either a training and or a control group. The training group [n = 11; mean (SD) age 63.0 (3.1) years] agreed to take part in a 12-week training programme at an exercise intensity kept under 60% of the heart rate reserve for about 60 min, 3 times a week. The control group [n = 9; mean (SD) age 63.5 (3.3) years] did not perform any particular physical training. Before and after the training period, all participants underwent anthropometric measures and a maximal cycling test to exhaustion to measure their VO2max. In addition, Wpeak was determined 1 week later by the subjects performing a vertical jump from a squatting position on a force platform. Following training, neither the anthropometric characteristics nor the VO2max changed in either of the groups. In contrast, Wpeak increased significantly (P < 0.001) in the training group, but did not change in the control group. This result could be interpreted as the result of an improved level of neuromuscular activation. Furthermore, it shows that although muscle power declines with age at a faster rate than does aerobic power, its sensitivity to training seems to be higher than that of the aerobic system.     

Aerobic power and insulin action improve in response to endurance exercise training in healthy 77-87 yr olds.

Previous studies have demonstrated that frail octogenarians have an attenuated capacity for cardiovascular adaptations to endurance exercise training. In the present study, we determined the magnitude of cardiovascular and metabolic adaptations to high-intensity endurance exercise training in healthy, nonfrail elderly subjects. Ten subjects [8 men, 2 women, 80.3 yr (SD2.5)] completed 10-12 mo (108 exercise sessions) of a supervised endurance exercise training program consisting of 2.5 sessions/wk (SD 0.2), 58 min/session (SD 6), at an intensity of 83% (SD 5) of peak heart rate. Primary outcomes were maximal attainable aerobic power [peak aerobic capacity (Vo(2peak))]; serum lipids, oral glucose tolerance, and insulin action during a hyperglycemic clamp; body composition by dual-energy X-ray absorptiometry, and energy expenditure using doubly labeled water and indirect calorimetry. The training program resulted in an increase in Vo(2peak) of 15% (SD 7) [22.9 (SD 3.3) to 26.2 ml.kg(-1).min(-1) (SD 4.0); P < 0.0001]. Favorable lipid changes included reductions in total cholesterol (-8%; P = 0.002) and LDL cholesterol (-10%; P = 0.003), with no significant change in HDL cholesterol or triglycerides. Insulin action improved, as evidenced by a 29% increase in glucose disposal rate relative to insulin concentration during the hyperglycemic clamp. Fat mass decreased by 1.8 kg (SD 1.4) (P = 0.003); lean mass did not change. Total energy expenditure increased by 400 kcal/day because of an increase in physical activity. No change occurred in resting metabolism. In summary, healthy nonfrail octogenarians can adapt to high-intensity endurance exercise training with improvements in aerobic power, insulin action, and serum lipid and lipoprotein risk factors for coronary heart disease; however, the adaptations in aerobic power and insulin action are attenuated compared with middle-aged individuals.     

THE EFFECT OF AEROBIC TRAINING ON SERUM ADIPONECTIN AND LEPTIN LEVELS AND INFLAMMATORY MARKERS OF CORONARY HEART DISEASE IN OBESE MEN

The aim of this study was to investigate the effect of 12 weeks of aerobic training on the serum levels of adiponectin and leptin and on inflammatory markers of coronary heart disease in obese men. Sixteen non-athlete obese men were randomly assigned to one of two experimental groups. The experimental group underwent aerobic training consisting of three sessions per week for 12 weeks, while the control group did not participate in the training programme during the study period. Five millilitres of venous blood was taken from each participant at the beginning of the study, during week six and at the end of week 12 to measure the levels of leptin, adiponectin, C-reactive protein, interleukin-6 and tumour necrosis factor-α. The findings showed that aerobic training led to decreases in the levels of CRP (P = 0.002), IL-6 (P = 0.001) and leptin (P = 0.003) and an increase in the level of adiponectin (P = 0.002) in the experimental group relative to the control group. In addition, the level of TNF-α decreased in the experimental group after the 12-week aerobic training period, although this change was not statistically significant. According to the results of this study, regular aerobic exercise decreases the potential risk of coronary heart disease by improving the plasma levels of IL-6, adiponectin, leptin and CRP. Additionally, aerobic exercise can be used as effective non-pharmacological treatment to prevent diseases.     

A Broad-Based Estimation of the Physical Work Capacity of Young Men

The physical work capacity of young men (17–21 years old) was estimated during this broad-based study. The subjects were divided into two groups depending on the level of their motor activity: those who were in general sport fitness programs (166 subjects) and those who had achieved high recognition in sports (149 subjects). Two stages in the development of physical work capacity in young men were detected. The first stage covered the 17- to 18-year-old men and was characterized by a significant increase in physical development and aerobic capacity, the improved hemodynamic responses to physical exercise, and a high tension in the cardiac regulatory mechanisms. The second stage (18–21 years) was a period of relative stabilization of physical development and body functions, during which the organism came to a new functional level typical of adulthood. A comparative analysis of the physical work capacity in subjects with different levels of motor activity showed that the indices of physical development, physical fitness, and aerobic capacity in 17-year-old athletes exceeded the same indices in the untrained age-matched group. Physical work capacity was significantly higher in athletes than in the untrained subjects during the whole juvenile period. In athletes the age-related physical fitness and aerobic capacity increased to a greater extent but physical development increased to a lesser extent than the same in the untrained subjects.     

Exercise Training Prevents Regain of Visceral Fat for 1 Year Following Weight Loss

The purpose of this study was to determine what effect aerobic and resistance exercise training has on gain of visceral fat during the year following weight loss. After being randomly assigned to aerobic training, resistance training, or no exercise training, 45 European‐American (EA) and 52 African‐American (AA) women lost 12.3 ± 2.5 kg on a 800 kcal/day diet. Computed tomography was used to measure abdominal subcutaneous and visceral adipose tissue, whereas total fat and regional fat (leg, arm, and trunk) were measured by dual energy X‐ray absorptiometry after weight loss and 1 year following the weight loss. Because not all the subjects adhered to the 2 time/week 40 min/day exercise training during the 1‐year follow‐up, subjects were divided into five groups for analysis: aerobic adherers, aerobic nonadherers, resistance adherers, resistance nonadherers, and no exercise. No significant differences were observed between the aerobic training and resistance training adherers for any variable. However, the aerobic (3.1 kg) and resistance (3.9 kg) exercise adherers gained less weight than any of the other three groups (all >6.2 kg). In addition, the two exercise adherence groups did not significantly increase visceral fat (<0.8%) as compared with the 38% increase for the two nonadhering exercise groups and the 25% for the nonexercise group. In conclusion, as little as 80 min/week aerobic or resistance training had modest positive effects on preventing weight regain following a diet‐induced weight loss. More importantly, both aerobic and resistance training prevented regain of potentially harmful visceral fat.     

Changes in physiological and anthropometric characteristics of rugby league players during a competitive season

This study investigated the physiological and anthropometric characteristics of rugby league players during a competitive season. Sixty-eight rugby league players were allocated into training (n = 52) and nonexercise control (n = 16) groups. The training group participated in 2 field-training sessions per week, with training loads, match loads, and injury rates recorded. Subjects performed measurements of standard anthropometry (height, body mass, and sum of 7 skinfolds), muscular power (vertical jump), speed (10-, 20-, and 40-m sprint), agility (L run), and maximal aerobic power (multistage fitness test) in December (off-season), March (preseason), May (midseason), and August (end season). Increases in maximal aerobic power and muscular power and reductions in skinfold thickness were observed during the early phases of the season when training loads were highest. However, reductions in muscular power and maximal aerobic power and increases in skinfold thickness occurred toward the end of the season, when training loads were lowest and match loads and injury rates were highest. These findings suggest that high overall playing intensity and match loads in end-season matches increase in injury rates in the latter half of the season, and residual fatigue associated with limited recovery between successive matches may compromise the physical development of rugby league players.     

The effects of magnesium supplementation on thyroid hormones of sedentars and Tae-Kwon-Do sportsperson at resting and exhaustion

The effect of magnesium on thyroid hormones of sedentars and sportsperson in Tae-Kwon-Do, has been investigated in a 4-weeks training program. Group 1 consisted of sedentars receiving 10 mg/kg/day Mg for 4 weeks. Group 2 consisted of subjects receiving magnesium (Mg) supplement and practicing Tae-Kwon-Do for 90-120 min/day, for five days a week. Group 3 consisted of subjects practicing Tae-Kwon-Do but receiving Mg supplements. TSH levels increased with training and Mg supplementation (p<0.05). Mg increased FT3 values. (p<0.05). TT3 values of groups reduced in all groups (p<005). After supplementation, group 1 had higher TT4 values than groups 1 and 3 and the group 2 had higher TT4 values than the third group (p<005). Results of this research show that training until exhaustion causes reduction in thyroid hormone activity in sedentars and sportsperson. It has been established that Mg supplementation however, prevents reduction in thyroid hormone activity in sedentars and sportsperson.     

Salivary hormonal responses and performance changes during 15 weeks of mixed aerobic and weight training in elite junior wrestlers

ABSTRACT: Passelergue, PA and Lac, G. Salivary hormonal responses and performance changes during 15 weeks of mixed aerobic and weight training in elite junior wrestlers. J Strength Cond Res 26(11): 3049-3058, 2012-To prepare efficiently for competition, wrestlers usually train physically for a period of approximately 12-20 weeks. Numerous physical qualities must be developed during this period of preparation: aerobic fitness, maximal strength, muscular endurance, power, and speed. However, numerous studies have concluded that it is difficult to concurrently develop strength and aerobic fitness for several reasons, in particular antagonistic endocrine variations. The study involved 15 elite junior wrestlers who trained at a sports training school for 15 weeks. To investigate the effects of long-term training and to assess the relationships between hormonal concentrations (salivary testosterone [T] and cortisol [C]) and performance changes during simultaneous strength and aerobic fitness training, 6 saliva samples and 3 physical tests and 2 measures of body composition were made during the training period. Wrestlers had a significant increase (+1.5 kg) in body weight without changes in percentage body fat. Apart from the 20-m maximal shuttle speed, all performances increased significantly during the 15 weeks of training: maximum mechanical power output (Pmax: +12.8%), mean power during 30 seconds (Pmean: +10.8%), bench press (+5.7%), squat (+23.1%), power clean (+6.1%), time to 3,000- and 30-m sprints (-3.6, -1.3% respectively). During the period that the C increased, there was no significant variation for the T. The T/C ratio followed a variation pattern contrary to that of the C. We found strong correlations between salivary T, C, and T/C and the variation in explosive strength. Our results suggest that data about subjects' salivary C, T, and T/C may be employed to optimize the training process for sports people who need to develop strength and aerobic fitness simultaneously.     

Activity-related changes of body fat and motor performance in obese seven-year-old boys

The effects of 35 weeks of extra-curricular, mainly aerobic, dynamic physical activity were analysed in overweight and obese 7-year-old boys contrasted with control groups. Body composition was estimated by using the body mass index (BMI) and skinfold thicknesses. Overweight or obesity was defined according to the suggestions of Cole and associates (2000). The activity program consisted of swimming and water games, folk dance, and soccer. Data were collected four times between September 2003 and October 2004. Thirty-one overnight or obese boys volunteered to participate in the activity program (weekly, to physical classes of 45 min. plus three extra-curricular activity sessions of 60 min. duration). The control subjects were 43 overweight or obese boys, and 75 non-overweight and non-obese ones. The controls had only two curricular physical education classes every week. Physical performance capacity was tested by 30 m dash, 400 m run, standing long jump, and fist-ball throw. Body fat content estimated by taking the sum of five skinfolds decreased significantly during the 35-week training program. However, body weight as well as skinfold thicknesses increased significantly during the four month non-active period that followed. Physical performance improved during the test period, but deteriorated between the third and fourth data collections. BMI, as well as the sum of five skinfolds increased in both control groups.Physical performance decreased in the overweight control subjects and increased moderately in the non obese ones. We inferred that more vigorous habitual exercise alone, i.e., without a program of dietary control, though effective, could not efficiently stabilise body fat, still less achieve a lasting reduction of it. Obese, but also overweight subjects need long term exercise programs of sufficient intensity, duration and frequency, plus dietary measures, to get rid of excess body fat.     

Performance changes following a field conditioning program in junior and senior rugby league players

This study investigated training loads, injury rates, and physical performance changes associated with a field conditioning program in junior and senior rugby league players. Thirty-six junior (16.9 [95% confidence interval: 16.7-17.1] years) and 41 senior (25.5 [23.6- 27.3] years) rugby league players participated in a 14-week preseason training program that included 2 field training sessions each week. Subjects performed measurements of standard anthropometry (height, body mass, and sum of 7 skinfolds), muscular power (vertical jump), speed (10-, 20-, and 40-m sprint), agility (L run), and maximal aerobic power (multistage fitness test) before and after training. Improvements in agility, muscular power, and maximal aerobic power were observed in both the junior and senior players following training; however, the improvement in maximal aerobic power and muscular power were greatest in the junior players. Training loads and injury rates were higher in the senior players. These findings demonstrate that junior and senior rugby league players adapt differently to a given training stimulus and that training programs should be modified to accommodate differences in training age.     

Effects of continuous and interval running training on serum growth and cortisol hormones in junior male basketball players

Effects of two different eight-week aerobic training programs consisting of continuous (CR) or extensive interval running (IR) on serum growth (GH) and cortisol hormones in 33 male basketball players aged 15-16 were assessed. The CR group ran 4.8 km and the IR group ran 4 x 1.2 km, using equal work-to-rest ratio, three times per week. Aerobic power scores of all subjects and anaerobic power marks of the training subjects increased (p<0.01). Upon exertion, though serum GH levels increased in both exercise groups (p<0.01) prior to and following training; cortisol levels increased only in the IR group prior to training, and in both exercise groups following training (p<0.05). Following the eight week period, resting cortisol levels rose in the training (p<0.05) and control (p<0.01) groups. To conclude, an 8-week training program consisting of continuous or extensive interval running has been effective on acute GH and cortisol secretion in 15-16 year-old male athletes.     

Effect of exercise training on total daily physical activity in elderly humans

This study examined the effect of 12 weeks of exercise training on daily physical activity in elderly humans. Training consisted of a weekly group session and an individual session with cardio- and weight-stack machines. A group of 15 subjects served as the exercise group [EXER mean age 59 (SD 4) years], and 7 subjects as the controls [CONT mean age 57 (SD 3) years]. Physical activity and physical fitness were measured before the start of training (T), at week 6 and week 12 (T0, T6, T12 respectively) in EXER, and at T0 and T12 in CONT. Physical activity over 14 days was measured using a tri-axial accelerometer and physical fitness was measured during an incremental exercise test. At T12, mean maximal power output had significantly increased in EXER compared to CONT 8 (SD 12) vs -5 (SD 9) W; P < 0.02] and mean submaximal heart rate (at 100 W) had reduced [-10 (SD 7) vs -2 (SD 6) beats x min(-1); P < 0.05]. No differences or changes in physical activity were observed between EXER and CONT. At T6, physical activity on training days was significantly higher than on non-training days (P < 0.001). When the accelerometer output of the training session was subtracted from the accelerometer output on training days, at T12 non-training physical activity was significantly lower than on non-training days (P < 0.004). Accelerometer output of the individual training session at T12 had significantly increased compared to T6 (P < 0.05), whereas, accelerometer output of the group training session had remained unchanged. In conclusion, in elderly subjects an exercise training programme of moderate intensity resulted in an improved physical fitness but had no effect on total daily physical activity. Training activity was compensated for by a decrease in non-training physical activity.     

Skill-based conditioning games as an alternative to traditional conditioning for rugby league players

This study investigated the effects of skill-based conditioning games and traditional conditioning for improving speed, agility, muscular power, and maximal aerobic power in rugby league players. Sixty-nine subelite rugby league players performed either a skill-based conditioning games program (N = 32) or a traditional conditioning (i.e., running activities with no skill component) program (N = 37). Each player participated in a 9-week in-season training program, performed over 2 competitive seasons. Players performed 2 organized field-training sessions each week. Players underwent measurements of speed (10-m, 20-m, and 40-m sprint), muscular power (vertical jump), agility (L run), and maximal aerobic power (multi-stage fitness test) before and after the training period. Skill-based conditioning games induced a significant improvement (p < 0.05) in 10-m, 20-m, and 40-m speed, muscular power, and maximal aerobic power, whereas traditional conditioning activities improved 10-m speed and maximal aerobic power only. No significant differences (p > 0.05) were detected between the traditional conditioning and skill-based conditioning games groups for changes in 10-m speed, agility, and maximal aerobic power. Both groups won 6 of 8 matches played within the training period, resulting in a win-loss ratio of 75%. However, on average, the skill-based conditioning games group scored more points in attack (p < 0.05) and had a greater (p < 0.05) points differential than the traditional conditioning group. The results of this study demonstrate that skill-based conditioning games offer an effective method of in-season conditioning for rugby league players. In addition, given that skills learned from skill-based conditioning games are more likely to be applied in the competitive environment, their use may provide a practical alternative to traditional conditioning for improving the physiological capacities and playing performance of rugby league players.     

Performance changes following training in junior rugby league players

The purpose of this study was to investigate the time course of adaptations to training in young (i.e., <15 years) and older (i.e., <18 years) junior rugby league players. Fourteen young (14.1 +/- 0.2 years) and 21 older (16.9 +/- 0.3 years) junior rugby league players participated in a 10-week preseason strength, conditioning, and skills program that included 3 sessions each week. Subjects performed measurements of standard anthropometry (i.e., height, body mass, and sum of 7 skinfolds), muscular power (i.e., vertical jump), speed (i.e., 10-m, 20-m, and 40-m sprint), agility (505 test), and estimated maximal aerobic power (i.e., multistage fitness test) before and after training. In addition, players underwent a smaller battery of fitness tests every 3 weeks to assess the time course of adaptation to the prescribed training stimulus. During the triweekly testing sessions, players completed assessments of upper-body (i.e., 60-second push-up, sit-up, and chin-up test) and lower-body (i.e., multiple-effort vertical jump test) muscular endurance. Improvements in maximal aerobic power and muscular endurance were observed in both the young and the older junior players following training. The improvements in speed, muscular power, maximal aerobic power, and upper-body muscular endurance were greatest in the young junior players, while improvements in lower-body muscular endurance were greatest in the older junior players. These findings demonstrate that young (i.e., <15 years) and older (i.e., <18 years) junior rugby league players adapt differently to a given training stimulus and that training programs should be modified to accommodate differences in maturational and training age. In addition, the results of this study provide conditioning coaches with realistic performance improvements following a 10-week preseason strength and conditioning program in junior rugby league players.     

Effects of Small-Sided Games vs. Interval Training in Aerobic Fitness and Physical Enjoyment in Young Elite Soccer Players

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.