The effects of game types on intensity of small-sided games among pre-adolescent youth football players.

The aim of this study was to examine the effects of variations in pitch dimensions on pre-adolescent youth soccer players' physiological responses during two different types of small-sided games (SSG). Sixteen young soccer players (age: 13.2 ± 0.6 years; body mass: 52.5 ± 7 kg; height: 163.4 ± 6 cm) participated in this study. They performed 4 vs. 4 stop-ball SSG (SB-SSG) vs. small-goals SSG (SG-SSG) with 4×4 min and 2 min of passive recovery in between, using 3 different pitch sizes (small: 10×15, medium: 15×20, and large: 20×25 m). Heart rate (HR), lactate concentration ([La-]), and rating of perceived exertion (RPE) were measured during each session. The results show that SB-SSG induced higher HR responses than SG-SSG for the 3 pitch sizes: for HR (167.2±3.0 vs. 164.5±3.0, 172.3±2.9 vs. 169.2±3.1, and 175.4±3.1 vs. 171.1±2.7 bpm; P<0.05, for small, medium, and large, respectively) and [La-] (7.1±1.0 vs. 6.5±1.04, 7.3±1.0 vs. 6.8±1.2, and 7.8±0.9 vs. 7.1±0.8 mmol·l-1; P<0.05 on small, medium, and large pitches, respectively), whereas RPE scores were significantly higher during SB-SSG compared to SG-SSG (6.2±1.0 vs. 5.8±0.9; P<0.05, respectively) on the small pitch. In the present study higher physiological responses were observed in SSG in pre-adolescent young soccer players when using the stop-ball conditions in comparison with the small-goal rule for all pitch sizes - small, medium, and large. Stop-ball conditions in comparison with the small-goal rule for all pitch sizes - small, medium, and large.

Soccer small-sided games in young players: rule modification to induce higher physiological responses.

The aim of this study was to identify the physiological responses of 3 forms of players' numbers during two different games rules of small-sided games (SSG: stop-ball vs. small-goals rules). Eighteen youth amateur soccer players (age 13.5±0.7 years; height 168.9±6.1cm; body mass 63.1±7.7 kg) participated in this study and performed 3 SSGs with varying players' number (2vs.2; 3vs.3 and 4vs.4): stop-ball SSG (SB-SSG) vs. small-goals SSG (SG-SSG) in a randomized and counter-balanced order on a constant pitch dimension (20×25m). The players performed 4×4 min SSG with 2-min of passive recovery in-between. Heart rate (HR), (expressed in bpm and % HRmax), lactate ([La-]), and rating of perceived exertion (RPE) were collected during each session. SB-SSG induced the higher HR values in comparison with the SG-SSG for the 3 game formats (2vs.2; 3vs.3 and 4vs.4). Also, compared with SG-SSG, SB-SSG induced the higher HR values during 2vs.2 compared with 4vs.4 games rules (178 vs. 174 and 175 vs. 171 bpm, respectively). However, the SB-SSG was more intense compared with SG-SSG in the 2 vs. 2 game rule compared with the two others (3 vs.3 and 4 vs. 4) for [La-] and RPE (7.58 vs. 7; 7.25 vs. 6.75 and 6.5 vs. 6.16 mmol ∙ L-1, and 7.75 vs. 7.33; 7.41 vs. 7.08 and 7.16 vs. 6.83, respectively). Therefore, the use of 2 vs. 2 and 3 vs. 3 SSG with SB-SSG seems to represent an alternative to coaches to increase cardiovascular and metabolic demands in youth soccer players.

Measurement errors when estimating the vertical jump height with flight time using photocell devices: the example of Optojump.

Common methods to estimate vertical jump height (VJH) are based on the measurements of flight time (FT) or vertical reaction force. This study aimed to assess the measurement errors when estimating the VJH with flight time using photocell devices in comparison with the gold standard jump height measured by a force plate (FP). The second purpose was to determine the intrinsic reliability of the Optojump photoelectric cells in estimating VJH. For this aim, 20 subjects (age: 22.50±1.24 years) performed maximal vertical jumps in three modalities in randomized order: the squat jump (SJ), counter-movement jump (CMJ), and CMJ with arm swing (CMJarm). Each trial was simultaneously recorded by the FP and Optojump devices. High intra-class correlation coefficients (ICCs) for validity (0.98-0.99) and low limits of agreement (less than 1.4 cm) were found; even a systematic difference in jump height was consistently observed between FT and double integration of force methods (-31% to -27%; p<0.001) and a large effect size (Cohen's d>1.2). Intra-session reliability of Optojump was excellent, with ICCs ranging from 0.98 to 0.99, low coefficients of variation (3.98%), and low standard errors of measurement (0.8 cm). It was concluded that there was a high correlation between the two methods to estimate the vertical jump height, but the FT method cannot replace the gold standard, due to the large systematic bias. According to our results, the equations of each of the three jump modalities were presented in order to obtain a better estimation of the jump height.

Greater effects of high- compared with moderate-intensity interval training on cardio-metabolic variables, blood leptin concentration and ratings of perceived exertion in obese adolescent females.

This study examined the effects of high- vs. moderate-intensity interval training on cardiovascular fitness, leptin levels and ratings of perceived exertion (RPE) in obese female adolescents. Forty-seven participants were randomly assigned to one of three groups receiving either a 1:1 ratio of 15 s of effort comprising moderate-intensity interval training (MIIT at 80% maximal aerobic speed: MAS) or high-intensity interval training (HIIT at 100% MAS), with matched 15 s recovery at 50% MAS, thrice weekly, or a no-training control group. The HIIT and MIIT groups showed improved (p < 0.05) body mass (BM), BMI Z-score, and percentage of body fat (%BF). Only the HIIT group showed decreased waist circumference (WC) (p = 0.017). The effect of exercise on maximal oxygen uptake (VO2max) was significant (p = 0.019, ES = 0.48 and p = 0.010, ES = 0.57, HIIT and MIIT, respectively). The decrease of rate-pressure product (RPP) (p < 0.05, ES = 0.53 and ES = 0.46, HIIT and MIIT, respectively) followed the positive changes in resting heart rate and blood pressures. Blood glucose, insulin level and the homeostasis model assessment index for insulin decreased (p < 0.05) in both training groups. Significant decreases occurred in blood leptin (p = 0.021, ES = 0.67 and p = 0.011, ES = 0.73) and in RPE (p = 0.001, ES = 0.76 and p = 0.017, ES = 0.57) in HIIT and MIIT, respectively. In the post-intervention period, blood leptin was strongly associated with %BF (p < 0.001) and VO2max (p < 0.01) in the HIIT and MIIT groups, respectively, while RPE was strongly associated with BM (p < 0.01) in the HIIT group. The results suggest that high-intensity interval training may produce more positive effects on health determinants in comparison with the same training mode at a moderate intensity.

Agility training in young elite soccer players: promising results compared to change of direction drills.

The aim of this study was to compare the effect of two different training programmes - change of direction (COD) vs. agility (AG) - on straight sprint (SS), COD and AG test performances in young elite soccer players. Thirty-two soccer players (age: 14.5±0.9 years; height: 171.2±5.1 cm; body mass: 56.4±7.1 kg, body fat: 10.3±2.3%) participated in a short-term (6 weeks) training study. Players were randomly assigned to two experimental groups - training with change of direction drills (COD-G, n=11) or using agility training (AG-G, n= 11) - and to a control group (CON-G, n=10). All players completed the following tests before and after training: straight sprint (15m SS), 15 m agility run with (15m-AR-B) and without a ball (15m-AR), 5-0-5 agility test, reactive agility test (RAT), and RAT test with ball (RAT-B). A significant group effect was observed for all tests (p<0.001; η2=large). In 15m SS, COD-G and AG-G improved significantly (2.21; ES=0.57 and 2.18%; ES=0.89 respectively) more than CON-G (0.59%; ES=0.14). In the 15m-AR and 5-0-5 agility test, COD-G improved significantly more (5.41%; ES=1.15 and 3.41; ES=0.55 respectively) than AG-G (3.65%; ES=1.05 and 2.24; ES=0.35 respectively) and CON-G (1.62%; ES=0.96 and 0.97; ES=0.19 respectively). Improvements in RAT and RAT-B were larger (9.37%; ES=2.28 and 7.73%; ES=2.99 respectively) in RAT-G than the other groups. In conclusion, agility performance amongst young elite soccer could be improved using COD training. Nevertheless, including a conditioning programme for agility may allow a high level of athletic performance to be achieved.

Do maximal aerobic power and blood lactate concentration affect Specific Judo Fitness Test performance in female judo athletes?

The Special Judo Fitness Test (SJFT) has become the test most widely used by coaches and physical trainers for assessment of competitors' judo-specific physical aptitude and training programme prescription. The aim of this study was to investigate the relationship between the SJFT performance indices and both maximal aerobic power and the level of blood lactate concentrations in female judo athletes. Seventeen female judokas (age: 21.9±1.6 years, body mass: 74.6±27.4 kg, height: 164.5±8.6 cm; BMI: 27.1±8.0 kg · m-2) took part in this study. All participants performed the SJFT, 20 m multi-stage shuttle run test (MSRT), and 30 m straight sprint test (SST), from which we calculated both acceleration (10 m) and the maximal anaerobic speed (MAnS: flying 20 m sprint). A blood sample was taken 3 min after the SJFT. The number of throws was significantly correlated with estimated VO2max (r=0.795, p=0.0001) and both acceleration (r=0.63, p =0.006) and MAnS (r=0.76, p=0.0004). Peak blood lactate recorded after the SJFT was 13.90±1.39 mmol · l-1. No significant correlation was found between blood lactate concentration and the SJFT performance indices. The lack of significant correlation between blood lactate and SJFT performance suggests that lactic anaerobic metabolism has no effect on this type of judo-specific supra-maximal exercise. The observed results can provide coaches and strength and conditioning professionals with relevant information for the interpretation of SJFT performance and the prescription of specific training programmes for female judo athletes.

Rapid weight loss in the context of Ramadan observance: recommendations for judokas.

Judo is a weight-classified combat sport, and many athletes seek to compete at the lightest possible weight category to gain an advantage from competing against shorter/smaller, and supposedly weaker opponents. To achieve a desired weight, most judokas opt for rapid weight loss techniques. Short-duration maximal efforts are not greatly affected by "making weight", but prolonged and/or repeated exercise is significantly impaired. Negative effects on mood, ratings of perceived exertion, and cognitive function are also reported. Moreover, rapid weight loss reduces maximal cardiac output and glycogen stores, and impairs thermo-regulation. Limited empirical data suggest that Ramadan reduces judokas' performance, and this is likely to be exacerbated by attempts at rapid weight loss. Weight reduction during Ramadan tends to be counterproductive, and judokas who aim for a lower weight category are advised to attempt any desired reduction of body mass during the weeks leading up to Ramadan, rather than during the holy month.

Vitamin D status and determinants of deficiency in non-supplemented athletes during the winter months in Tunisia.

Recent reports suggest that hypovitaminosis D in athletes is as common as in the general population. This study was devised to examine vitamin D status and determinants of deficiency in athletes living in a sunny country (Tunisia). One hundred and fifty national elite athletes, training outdoors (n = 83) or indoors (n = 67), were enrolled from January to February 2012. Plasma 25-hydroxyvitamin D was measured by radioimmunoassay. Concentrations were between 50 and 75 nmol · l(-1) in 21.3% of participants, between 25 and 50 nmol · l(-1) in 55.3% of participants and <25 nmol · l(-1) in 14.7% of participants. The concentrations were significantly lower in indoor athletes than outdoor athletes (36.2±19.0 nmol · l(-1) vs. 49.1±19.2 nmol · l(-1); p < 0.001). In multivariate analysis, vitamin D deficiency (25-hydroxyvitamin D <50 nmol · l(-1)) was associated with indoor sports [multi-adjusted odds ratio (95% confidence interval), 5.03 (1.64-15.4); p = 0.005], female gender [3.72 (1.44-9.65); p = 0.007] and age < 18 years [2.40 (1.01-5.85); p = 0.05]. Athletes living in sun-rich environments are exposed to a high risk of vitamin D inadequacy. Given the importance of vitamin D in health and athletic ability, targeting sufficient levels of plasma 25-hydroxyvitamin D in athletes is well justified.

Anthropometric and physiological characteristics of Melanesian futsal players: a first approach to talent identification in Oceania.

This study assessed the anthropometric and physiological characteristics of elite Melanesian futsal players in order to determine the best performance predictors. Physiological parameters of performance were measured in 14 Melanesian (MEL-G, 24.4±4.4 yrs) and 8 Caucasian (NMEL-G, 22.9±4.9) elite futsal players, using tests of jump-and-reach (CMJ), agility (T-Test), repeated sprint ability (RSA), RSA with change-of-direction (RSA-COD), sprints with 5 m, 10 m, 15 m, and 30 m lap times, and aerobic fitness with the 30-15 intermittent fitness test (30-15 IFT). The anthropometric data revealed significantly lower height for MEL-G compared with NMEL-G: 1.73±0.05 and 1.80±0.08 m, respectively; P = 0.05. The CMJ was significantly higher for MEL-G than NMEL-G: 50.4±5.9 and 45.2±4.3 cm, respectively; P = 0.05. T-Test times were significantly lower for MEL-G than NMEL-G: 10.47±0.58 and 11.01±0.64 seconds, respectively; P = 0.05. MEL-G height was significantly related to CMJ (r = 0.706, P = 0.01), CMJpeakP (r = 0.709, P = 0.01) and T-Test (r = 0.589, P = 0.02). No significant between-group differences were observed for sprint tests or 30-15 IFT, including heart rate and estimated VO2max. Between groups, the percentage decrement (%Dec) in RSA-COD was significantly lower in MEL-G than NMEL-G (P = 0.05), although no significant difference was noted between RSA and RSA-COD. Within groups, no significant difference was observed between %Dec in RSA or RSA-COD; P = 0.697. This study presents specific anthropometric (significantly lower height) and physiological (significantly greater agility) reference values in Melanesians, which, taken together, might help coaches and physical fitness trainers to optimize elite futsal training and talent identification in Oceania.

Validity of the MarkWiiR for kinematic analysis during walking and running gaits.

The aim of this study was to validate the MarkWiiR (MW) captured by the Nintendo Wii-Remote (100-Hz) to assess active marker displacement by comparison with 2D video analysis. Ten participants were tested on a treadmill at different walking (1<6 km · h(-1)) and running (10<13 km · h(-1)) speeds. During the test, the active marker for MW and a passive marker for video analysis were recorded simultaneously with the two devices. The displacement of the marker on the two axes (x-y) was computed using two different programs, Kinovea 0.8.15 and CoreMeter, for the camera and MW, respectively. Pearson correlation was acceptable (x-axis r≥0.734 and y-axis r≥0.684), and Bland-Altman plots of the walking speeds showed an average error of 0.24±0.52% and 1.5±0.91% for the x- and y-axis, respectively. The difference of running speeds showed average errors of 0.67±0.33% and 1.26±0.33% for the x- and y-axes, respectively. These results demonstrate that the two measures are similar from both the x- and the y-axis perspective. In conclusion, these findings suggest that the MarkWiiR is a valid and reliable tool to assess the kinematics of an active marker during walking and running gaits.

Bench press exercise: the key points.

The bench press exercise (BPE) is receiving increasing interest as a field testing, training/therapeutic modality to improve neuromuscular performance or to increase bone mass density. Several studies have been performed using BPE as a standard for increasing upper-limb strength. For this purpose, the position of the bar, the loads, the sets, the number of repetitions, the recovery time in-between sets, the movement speed, the muscular work and the use of the determination of the one repetition maximum (1-RM) are the classical tools investigated in the literature that have been shown to affect the BPE effect on neuromuscular. The goal of the present short review is to make a picture of the current knowledge on the bench press exercise, which could be very helpful for a better understanding of this standard movement and its effects. Based on the related literature, several recommendations on these key points are presented here.

Relationships between heart rate and physiological parameters of performance in top-level water polo players.

The aim of this study was to measure the heart rate (HR) response of eight elite water polo players during the four 7-min quarters of the game and to check for relationships with the physiological parameters of performance ([Formula: see text]O2max, Th1vent, Th2vent). Each athlete performed a [Formula: see text]O2max treadmill test and played a water polo game wearing a heart rate monitor. The game fatigue index was calculated as the ratio of the fourth-quarter HR to the first-quarter HR: HR4/HR1. The results showed a slight decrease in fourth-quarter HR compared with the first quarter, with the mean four-quarter HR equal to 79.9±4.2% of HRmax. Stepwise multiple regression analysis showed [Formula: see text]O2max to be the main explanatory factor of game intensity, i.e. game HR expressed in %HRreserve (R=0.88, P<0.01). We observed that higher aerobic capacity resulted in higher game intensity. We also observed a decrease in the playing intensity in the fourth quarter compared with the first, likely due to very high game involvement. We concluded that high aerobic capacity seems necessary to ensure high game intensity in water polo. This suggests that coaches should encourage their athletes to reach a minimum level of [Formula: see text]O2max and that HR monitoring could be of great interest in the control of water polo training sessions.

Greater volumes of static and dynamic stretching within a warm-up do not impair star excursion balance performance.

Based on the conflicting static stretching (SS) literature and lack of dynamic stretching (DS) literature regarding the effects of differing volumes of stretching on balance, the present study investigated the effects of 4, 8, and 12 sets of SS and DS following a 5 min aerobic running warm-up on the star excursion balance test (SEBT). The objective was to examine an optimal stretch modality and volume to enhance dynamic balance. A randomized, within-subjects experimental design with repeated measures for stretching (SS and DS) versus no-stretching treatment was used to examine the acute effects of 10 (4 sets), 20 (8 sets), and 30 (12 sets) min, of 15s repetitions per muscle of SS and/or DS following a 5 min aerobic warm-up on the performance of the SEBT. Results indicated that a warm-up employing either SS or DS of any volume generally improves SEBT by a "small" amount with effect sizes ranging from 0.06 to 0.50 (11 of 18 conditions>75% likely to exceed the 1.3-1.9% smallest worthwhile change). Secondly, the difference between static and dynamic warm-up on this observed improvement with warm-up improvement was "trivial" to "moderate" (d=0.04 to 0.57) and generally "unclear" (only two of nine conditions>75% likely to exceed the smallest worthwhile change). Finally, the effect of increasing the volume of warm-up on the observed improvement with a warm-up is "trivial" to "small" (d<0.40) and generally "unclear" (only three of 12 conditions>75% likely to exceed the smallest worthwhile change). In summary, an aerobic running warm-up with stretching that increases core and muscle temperature whether it involves SS or DS may be expected to provide small improvements in the SEBT.

Anaerobic upper and lower body power measurements and perception of fatigue during a kick boxing match.

AIM: Objective of the study was to determine the effects of a kick-boxing match on muscle power of the upper and lower body as well as the associated perceived exertion in young men. METHODS: Eighteen well trained kick-boxers volunteered to participate in a competitive sparring bout preceded and followed by three anaerobic tests as follow: squat jump (SJ) and counter movement jump (CMJ) for legs and 30-s Wingate test for arms. The sparring bout consisted of three 2 min rounds with 1 min recovery period in-between. Blood lactate (BL), heart rate (HR) and rating of perceived exertion (RPE) were analyzed before and after each round. RESULTS: The results showed that vertical jump distance in SJ and CMJ were significantly lower after the kick-boxing match (27.92±3.84 vs. 25.28±4.39 cm; 29.8±5.33 vs 28.48±4.64 cm, for SJ and CMJ respectively). Likewise, peak and mean power in the Wingate test decreased significantly after the sparring bout (5.89±0. 69 vs. 5.26±0.66 W•kg-1 and 4.51±0.53 vs. 4.12±0.51 W•kg-1 for PP and MP respectively; P<0.001). Moreover, we found a significant increase in BL, HR, and RPE after the kick-boxing match (P<0.001). BL increased significantly after the second and third round from the post round one values' (P<0.001). CONCLUSION: These findings showed that a single kick-boxing match is of sufficient intensity to stress the anaerobic metabolism. Thus, training protocols should include exercises that train the anaerobic energetic pathways for upper and lower body.

High intensity exercise affects diurnal variation of some biological markers in trained subjects.

The study investigated if markers of muscle injury and antioxidant status were affected by a Wingate test performed at 2 different times of day. 15 young male footballers performed 2 tests (randomized) at 07:00-h and 17:00-h. Fasting blood samples were collected before and 3 min after each test for assessment of markers of muscle injury and antioxidant status. Resting oral temperature was recorded during each session. Peak power (10.76 ± 1.05 vs. 11.15 ± 0.83 W.kg( - 1)) and fatigue index (0.41 ± 0.04 vs. 0.49 ± 0.13%) during the Wingate test, and core temperature, were significantly higher (all p<0.05) in the evening. Markers of muscle injury were significantly higher in the evening before and after exercise (e. g., 148.7 ± 67.05 vs. 195 ± 74.6 and 191.6 ± 79.52 vs. 263.6 ± 96.06 IU.L (- 1), respectively, for creatine kinase; both p<0.001). Antioxidant parameters increased after the Wingate test but only resting values were significantly higher in the morning (e. g., 1.33 ± 0.19 vs. 1.19 ± 0.14 µmol.L (- 1) for total antioxidant status; p<0.05). The results indicate that muscle injury and antioxidant activity after the Wingate test were higher in the evening, suggesting a possible link between the biochemical measures and the diurnal fluctuation of anaerobic performance. However, repetition of this study after prescribed rather than self-selected exercise intensity is recommended.

Comparison of ground reaction forces and contact times between 2 lateral plyometric exercises in professional soccer players.

There are no studies which have examined the differences in kinetics between lateral plyometric exercises and the selection of these exercises is largely based on the experience and observation of coaches. This study aimed to compare ground reaction forces (GRF) and contact times (GCT) between 2 lateral plyometric exercises: lateral alternative leg hopping (HOP), and speed lateral footwork (SPEED). 16 professional male soccer players (age: 24.6±5.5 years; and BMI: 21.7±2.2 kg.m - 2) participated in this within-participant repeated measures study. 3-dimensional GRF data were measured by force platform. Our study revealed significant differences between the 2 lateral plyometric exercises in all kinetics parameters (F=573.7, P<0.01). HOP produced significantly longer GCT (0.45 s vs. 0.23 s, P<0.01, large effect), significantly higher values (P<0.05, large effect) in peak force (3.31 vs. 2.47 Body Weight [BW]), peak rate of force development (0.94 vs. 0.29 BW/s), and impulse (0.76 vs. 0.31 BW.s) except for peak force in the medial-lateral (P<0.05, medium effect) and impulse in the anterio-posterior direction (not significant, small effect). Therefore, SPEED is an exercise that aims to increase step frequency because of its short GCT (< 0.25 s) while HOP increases leg strength and power.

The effect of time-of-day and Ramadan fasting on anaerobic performances.

This study was designed to assess the effects of Ramadan-intermittent-fasting (RIF) and time-of-day on muscle power and fatigue during the Wingate test. In a randomized design, 10 football players completed a Wingate test at 07:00 and 17:00 h on 3 different occasions: one week before Ramadan (BR), the second week of Ramadan (SWR) and the fourth week of Ramadan (ER). There was an interval of 36-h between any 2 successive tests. During the Wingate test, peak power (PP), mean power (MP) and the fatigue index (FI) were recorded. While PP, MP and FI were greater in the evening than in the morning during BR (p<0.001), these diurnal variations in muscle power disappeared during the month of Ramadan (i. e., SWR and ER) due to a significant decrease in PP and MP in the evening (p<0.001). However, the diurnal variation in FI when measured at 17:00 h increased during this month (p<0.001). In addition, ratings of perceived exertion and fatigue were higher in the evening during Ramadan in comparison with BR. These results suggest that Ramadan might modify the circadian rhythm of muscle power and fatigue during the Wingate test by decreasing power output and increasing muscle fatigue at the time of the acrophase.

Listening to music affects diurnal variation in muscle power output.

The purpose of this investigation was to assess the effects of listening to music while warming-up on the diurnal variations of power output during the Wingate test. 12 physical education students underwent four Wingate tests at 07:00 and 17:00 h, after 10 min of warm-up with and without listening to music. The warm-up consisted of 10 min of pedalling at a constant pace of 60 rpm against a light load of 1 kg. During the Wingate test, peak and mean power were measured. The main finding was that peak and mean power improved from morning to afternoon after no music warm-up (p<0.001 and p<0.01, respectively). These diurnal variations disappeared for mean power and persisted with an attenuated morning-evening difference (p<0.05) for peak power after music warm-up. Moreover, peak and mean power were significantly higher after music than no music warm-up during the two times of testing. Thus, as it is a legal method and an additional aid, music should be used during warm-up before performing activities requiring powerful lower limbs' muscles contractions, especially in the morning competitive events.

Stretch and sprint training reduces stretch-induced sprint performance deficits in 13- to 15-year-old youth.

The recently reported static stretching impairments found in adults have not been studied in youth. Furthermore, stretch-training effects on sprint performance are equivocal, hence the purpose of this study was to examine the effect of stretch and sprint training on the acute effects of static stretching in 13-15 year olds. A total of 48 students were randomly divided into a sprint only and a stretch and sprint training groups who performed static stretching at the beginning and middle of the speed training sessions (6 weeks). Flexibility tests and 30-m sprints were performed before and after training. Sprint performance was evaluated with and without prior stretching. A main effect indicated that prior static stretching impairs sprint times at 10 (P = 0.01) and 30 m (P = 0.0005). Both groups improved times over 10 (0.7%; P = 0.04) and 30-m (1.5%; P = 0.0007) sprint distance after training. Stretch and sprint trained participants were more resistant to stretch-induced sprint deficits with 3.2% (P < 0.0001), 3.6% (P = 0.0002) and 1.3% (P < 0.0001) faster times at 5, 10, and 30 m, respectively, than the sprint only group. In conclusion, a stretch and sprint training program in 13-15 year olds diminished the detrimental effects of static stretching compared to a sprint only training program.

Lipid profiles of judo athletes during Ramadan.

The effect of Ramadan intermittent fasting (RIF) was studied on a battery of blood lipid markers in 15 elite judo athletes during a period when they were maintaining their training load without competing. Nine-to-twelve hours postprandial serum lipid and lipoproteins were measured on five occasions: before, three times during Ramadan, and three weeks post-Ramadan. Dietary data were collected using a 24-hour recall method for three days before, during and after the Ramadan month. Mean energy intake (12.9 MJ/d) remained similar throughout the study as did the macronutrient constituents of the diet. Mean body mass was slightly reduced (2 %; p < 0.01) by the end of Ramadan due mainly to a 0.65 +/- 0.68 kg decrease in body fat (p < 0.05). The RIF produced significant changes in some of the blood lipid levels: both HDL-C and LDL-C increased by 0.12 (p < 0.01) and 0.20 mmol . l (-1) (p < 0.05), respectively. During Ramadan, mean non-esterified fatty acid (NEFA) levels decreased from 0.73 to 0.28 mmol . l (-1) (p < 0.01) during the first week, then increased (p < 0.05) to 1.22 mmol . l (-1) over the middle of Ramadan and recovered to pre-Ramadan concentrations for the end and the post-Ramadan periods. Apolipoprotein A1 (Apo-A1) levels were significantly elevated at the end (p < 0.01) and the post-Ramadan periods (p < 0.05). Three weeks after Ramadan, blood levels of glucose, NEFA, Apo-A1, and Apo-B did not return to the values observed before Ramadan. In conclusion, the present results show that the combination of the change in diet pattern during Ramadan, along with intense exercise training, induced a significant decrease in body mass associated with a reduction in body fat and changes in some of the serum lipids and lipoproteins. Nevertheless, all the measured serum parameters remained within normal levels for young and active individuals. The volunteers, in this study, were able to maintain a constant training load during RIF.