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1.
This study aimed to compare youth football players’ performance during two small-sided games with different pitch orientation: i) 40x30m and ii) 30x40m formats. Twenty under-15 players (age = 14.1 ± 0.5 years) participated in nine GK+4vs4+GK situations in each format, with the duration of six minutes each. Positional data were collected using individual GPS units, and computed for tactical and physical performance indicators. The SSG were video recorded, using notational analysis for collecting technical indicators. A novel method that incorporates time dependent notational information with spatiotemporal data was used to compute multidimensional parameters. Standardised effect sizes and non-clinical magnitude-based inferences were used to compare formats. Results showed that players covered more distance at higher intensities, presented more passes and dribbles and were more synchronised in the longitudinal axis while playing in the 40x30m pitch. In the 30x40m pitch, results showed a lower distance between team centroids, higher number of shots, more lateral passes and a wider team positioning. Multidimensional indicators, as players position and distance to the closest defender while shooting, revealed a more constant distance between attacker and defender in the 40x30m pitch. These results highlight the importance of integrating information from different indicators for a contextually valid information.  相似文献   

2.
In a randomised controlled trial design, effects of 6 weeks of plyometric training on maximal-intensity exercise and endurance performance were compared in male and female soccer players. Young (age 21.1 ± 2.7 years) players with similar training load and competitive background were assigned to training (women, n = 19; men, n = 21) and control (women, n = 19; men, n = 21) groups. Players were evaluated for lower- and upper-body maximal-intensity exercise, 30 m sprint, change of direction speed and endurance performance before and after 6 weeks of training. After intervention, the control groups did not change, whereas both training groups improved jumps (effect size (ES) = 0.35–1.76), throwing (ES = 0.62–0.78), sprint (ES = 0.86–1.44), change of direction speed (ES = 0.46–0.85) and endurance performance (ES = 0.42–0.62). There were no differences in performance improvements between the plyometric training groups. Both plyometric groups improved more in all performance tests than the controls. The results suggest that adaptations to plyometric training do not differ between men and women.  相似文献   

3.
Improved understanding of mobility performance in wheelchair basketball is required to increase game performance. The aim of this study was to quantify the wheelchair-athlete activities of players in different field positions and of different playing standard during wheelchair basketball matches. From video analysis, absolute and relative duration and frequency of wheelchair movements and athlete control options were examined in 27 national standard and 29 international standard players during entire wheelchair basketball matches. Between-group factorial analysis of variances identified that national players drove more forward (42.6 ± 6.8 vs. 35.4 ± 3.7%; effect size Cohen’s d (ES) = 1.48) and started more often driving forward (33.9 ± 2.6 vs. 31.8 ± 2.8; ES = 0.77) during a match while the mean activity duration for a single driving forward activity was longer (4.3 ± 0.9 vs. 3.7 ± 0.6 s; ES = 0.75) than for international players. Furthermore, national players performed fewer rotational movements (21.8 ± 4.0 vs. 28.9 ± 7.8%; ES = –1.30) and started less often with the rotational movements (35.0 ± 3.6 vs. 40.5 ± 5.5; ES = –1.21) while the mean activity duration for a single rotation activity was shorter (2.1 ± 0.3 vs. 2.3 ± 0.3 s; ES = –0.67) than for international players. Differences in mobility performance among guard, forward and centre players were minimal. The results should help wheelchair basketball coaches specify wheelchair-handling training techniques and means to optimise wheelchair-athlete configurations.  相似文献   

4.
Abstract

The purpose of this study was to assess the effects of heavy resistance, explosive resistance, and muscle endurance training on neuromuscular, endurance, and high-intensity running performance in recreational endurance runners. Twenty-seven male runners were divided into one of three groups: heavy resistance, explosive resistance or muscle endurance training. After 6 weeks of preparatory training, the groups underwent an 8-week resistance training programme as a supplement to endurance training. Before and after the 8-week training period, maximal strength (one-repetition maximum), electromyographic activity of the leg extensors, countermovement jump height, maximal speed in the maximal anaerobic running test, maximal endurance performance, maximal oxygen uptake ([Vdot]O2max), and running economy were assessed. Maximal strength improved in the heavy (P = 0.034, effect size ES = 0.38) and explosive resistance training groups (P = 0.003, ES = 0.67) with increases in leg muscle activation (heavy: P = 0.032, ES = 0.38; explosive: P = 0.002, ES = 0.77). Only the heavy resistance training group improved maximal running speed in the maximal anaerobic running test (P = 0.012, ES = 0.52) and jump height (P = 0.006, ES = 0.59). Maximal endurance running performance was improved in all groups (heavy: P = 0.005, ES = 0.56; explosive: P = 0.034, ES = 0.39; muscle endurance: P = 0.001, ES = 0.94), with small though not statistically significant improvements in [Vdot]O2max (heavy: ES = 0.08; explosive: ES = 0.29; muscle endurance: ES = 0.65) and running economy (ES in all groups < 0.08). All three modes of strength training used concurrently with endurance training were effective in improving treadmill running endurance performance. However, both heavy and explosive strength training were beneficial in improving neuromuscular characteristics, and heavy resistance training in particular contributed to improvements in high-intensity running characteristics. Thus, endurance runners should include heavy resistance training in their training programmes to enhance endurance performance, such as improving sprinting ability at the end of a race.  相似文献   

5.
Parachute jump is an extreme activity that elicits an intense stress response that affects jumpers’ body systems being able to put them at risk. The present research analysed modifications in blood oxygen saturation (BOS), heart rate (HR), cortisol, glucose, lactate, creatine kinase (CK), muscles strength, cortical arousal, autonomic modulation, pistol magazine reload time (PMRT) and state anxiety before and after an automatic open parachute jump in 38 male Spanish soldiers (25.6 ± 5.9 years). A MANOVA with samples as a fixed factor and Effect Size (ES) were conducted. MANOVA showed (Wilks lambda = .225; F = 5.980; P = .000) a significantly increase in cortisol (6.2 ± 3.2 vs. 8.2 ± 4.3 nmol/l; P = .025; ES = .47), HR (75.0 ± 14.6 vs. 87.4 ± 17.3 bpm; P = .004; ES = .72), lactate (1.8 ± 1.2 vs. 4.4 ± 2.2 mmol · l?1; P = .002; ES = 1.18), sympathetic nervous system and leg strength manifestation after the parachute jump. By contrary BOS, PMRT (55.6 ± 27.6 vs. 48.0 ± 16.7 s; P = .021; ES = .46) and somatic anxiety (SA), evaluated by CSAI2R questionnaire, decreased. An automatic parachute jump increased physiological and cortical response and decreased SA of participants. This stress response can affect the jumpers’ abilities and allow us to have a better understanding of the organism stress response and to improve training for both military and sport parachute jumps.  相似文献   

6.
ABSTRACT

This study investigated the effects of a congested match schedule (7 matches played in 7 days) on steroid hormone concentrations, mucosal immunity, session rating of perceived exertion (S-RPE) and technical performance in 16 elite youth soccer players (14.8 ± 0.4 years; 170.6 ± 9.4 cm; 64.9 ± 7 kg). No change was observed for salivary cortisol concentration across match time points (P = 0.33; effect size [ES] = 0.13–0.48). In contrast, there was a decrease in salivary testosterone and salivary IgA (SIgA) concentrations from the 1st compared with the last time point (P = 0.01 and 0.001, ES = 0.42 and 0.67, respectively). The SIgA concentration varied across time points (P < 0.001) with the highest value observed at the 3rd time point (rest day) (3rd vs all time point; ES = 0.47–0.73). No changes were observed for S-RPE across time points (P > 0.05). A higher number of tackles and interceptions were observed during the 4th match vs 1st and 7th matches (P < 0.001; ES = 2.25 and 1.90, respectively). The present data demonstrate that accumulated fatigue related to participation in a congested match schedule might induce a decrease in testosterone concentration in youth players and negatively affect their mucosal immunity and capacity to perform certain technical actions.  相似文献   

7.
ABSTRACT

This study aimed to investigate between- and within-team changes in workload [PlayerLoad (PL), training impulse (TRIMP) and session rate of perceived exertion training load (sRPE-TL)], readiness [heart rate variability (HRV)], and physical performance [20-m sprint test (including 10-m split time), countermovement jump (CMJ) and yo-yo intermittent recovery test level 1 (YYIR1)] during 3-week intensified preparation periods in female, national Under18 (n = 12, age = 18.0 ± 0.5y, stature = 180.4 ± 7.5 cm, body mass = 72.7 ± 9.3 kg) and Under20 (n = 12, age = 19.6 ± 0.8y, stature = 178.6 ± 6.4 cm, body mass = 68.0 ± 5.9 kg) basketball teams. Under18 team revealed small-to-moderate statistically significantly higher values in workload [PL: p = 0.010; ES = Small; TRIMP: p = 0.004; ES = Moderate; sRPE-TL: p < 0.001; ES = Moderate] and moderately lower readiness values (p = 0.023; ES = Moderate) compared to Under20. Within-team analysis showed no differences in workload in Under20 and statistically significant reduction (p < 0.05) in Week3 (taper period) in Under18. Pre- and post-preparation changes showed Under18 increasing only YYIR1 performance (p < 0.001; ES = Very large). Differently, Under20 statistically improved in 10-m split time (p = 0.003; ES = Moderate), CMJ (p = 0.025; ES = Moderate) and YYIR1 (p < 0.001; ES = Large). A constant adequate workload positively benefits players’ readiness and physical performances during short intensified preparation periods. Conversely, using high workload with periodization strategies encompassing short overload and taper phases induced positive changes on players’ aerobic performance, lower readiness values and no changes in anaerobic performances.  相似文献   

8.
Purpose: In a cross-sectional study design, we evaluated the resting heart rate (HRbaseline) and exercise and postexercise stress test-related chronotropic responses in male practitioners of recreational ballroom dancing (BD; n = 25, Mage = 26.6 ± 6.1 years) compared to a control group of insufficiently active nondancers (CG; n = 25, Mage = 25.9 ± 4.5 years). Method: All participants underwent a submaximal exercise test. At 85% of the maximal predicted HR, the recovery protocol was started, and heart rate recovery (HRR) was recorded during 1-min intervals for 5 min. Results: Compared with CG, BD showed lower HRbaseline (70 beats per minute [bpm] vs. 62 bpm, respectively, U = 143, p < .05, ES = .46), lower preexercise HR (94 bpm vs. 86 bpm, U = 157, p < .05, ES = .42), longer exercise test duration (346 s vs. 420 s, U = 95.5, p < .05, ES = .59), and higher HRR for 5 min postexercise (U = 1.29–1.89, p < .05, ES = .33–.50) as follows: 1st min (32 bpm vs. 40 bpm), 2nd min (45 bpm vs. 53 bpm), 3rd min (51 bpm vs. 58 bpm), 4th min (55 bpm vs. 59 bpm), and 5th min (59 bpm vs. 63 bpm). The coefficient of HRR from the 1st min to the 5th min postexercise was similar in both groups (U = 229–311, p > .05, ES = < .10–.22). Conclusion: Heightened cardiovascular functional status characterized by favorable enhanced chronotropic dynamics appears to occur in practitioners of recreational ballroom dancing, which suggests that this modality of exercise may result in health benefits.  相似文献   

9.
Purpose: The present study aimed to investigate whether or not eccentric-only training induced different sex-related adaptations in vastus lateralis muscle architecture and knee extensors strength. Methods: Thirteen healthy women and 13 healthy men were recruited. Vastus lateralis pennation angle, fascicle length, and muscle thickness, as well as knee extensors eccentric, isometric, and concentric peak torque and one-repetition maximum (1RM) were measured. Both women and men underwent a unilateral iso-load knee-extension eccentric-only training with 120% of the concentric 1RM, consisting of 4 sets × 10 repetitions twice a week for a total of 8 weeks. Results: Pennation angle increased in women (+ 14%, 95% CI [10, 17], effect size [ES] = 1.54) but not in men (+ 5%, 95% CI [?1, 11], ES = 0.28), while fascicle length increased in both women (+ 7%, 95% CI [4, 10], ES = 1.02) and men (+ 12%, 95% CI [8, 16], ES = 1.82) and muscle thickness increased in women (+ 13%, 95% CI [8, 18], ES = 1.11) and men (+ 11%, 95% CI [7, 15], ES = 0.89). In both women and men, eccentric (18%, 95% CI [11, 25], ES = 0.96, and 16%, 95% CI [9, 22], ES = 0.82, respectively), isometric (17%, 95% CI [11, 23], ES = 0.53, and 17%, 95% CI [10, 24], ES = 0.62), concentric (12%, 95% CI [7, 16], ES = 0.49, and 9%, 95% CI [5, 13], ES = 0.42) peak torque and 1RM (10%, 95% CI [6, 14], ES = 0.53, and 10%, 95% CI [5, 15], ES = 0.50) similarly increased after the intervention. Conclusions: This study showed that the adaptations in strength are not sex-dependent, but the increases in pennation angle only in women suggest that the changes in muscle architecture may depend on sex.  相似文献   

10.
To determine the effect of circadian rhythm on neuromuscular responses and kinematics related to physical tennis performance, after a standardised warm-up, 13 highly competitive male tennis players were tested twice for serve velocity/accuracy (SVA), countermovement vertical jump (CMJ), isometric handgrip strength (IS), agility T-test (AGIL) and a 10-m sprint (10-m RUN). In a randomised, counter-balance order, tennis players underwent the test battery twice, either in the morning (i.e., AM; 9:00 h) and in the afternoon (i.e., PM; 16:30 h). Paired t-tests were used to analyse differences due to time-of-day in performance variables. Comparison of morning versus afternoon testing revealed that SVA (168.5 ± 6.5 vs. 175.2 ± 6.1 km · h?1; P = 0.003; effect size [ES] = 1.07), CMJ (32.2 ± 0.9 vs. 33.7 ± 1.1 cm; P = 0.018; ES = 1.46), AGIL (10.14 ± 0.1 vs. 9.91 ± 0.2 s; P = 0.007; ES = 1.23) and 10-m RUN time (1.74 ± 0.1 vs. 1.69 ± 0.1 s; P = 0.021; ES = 0.67) were significantly blunted during the morning testing. However, IS was not affected by time-of-day (P = 0.891). Thus, tennis performance may be reduced when competing in the morning in comparison to early evening. Therefore, coaches and tennis players should focus on schedule the SVA, power, speed and agility training sessions in the afternoon.  相似文献   

11.
Acute exercise reduces postprandial triacylglycerol concentrations ([TAG]) in boys and girls; however, it is not known whether between-sex differences exist in response to exercise. Fifteen boys (mean(SD): 11.8(0.4) years) and sixteen girls (12.1(0.7) years) completed two, 2-day conditions. On day 1, participants rested (CON) or completed 10 × 1 min high-intensity interval runs at 100% maximal aerobic speed with 1 min recovery (HIIR). On day 2, participants consumed a standardised breakfast and lunch over a 6.5-h period during which seven capillary blood samples were collected. Based on ratios of the geometric means (95% CI for ratios), fasting [TAG] was 32% lower in boys than girls (?44 to ?18%, ES = 1.31, P < 0.001), and 12% lower after HIIR than CON (?18 to ?5%, ES = 0.42, P = 0.003); the magnitude of reduction was not significantly different between the sexes (8% (ES = 0.36) vs. 15% (ES = 0.47), respectively; P = 0.29). The total area under the [TAG] versus time curve was 27% lower in boys than girls (?40 to ?10%, ES = 1.02, P = 0.005), and 10% lower after HIIR than CON (?16 to ?5%, ES = 0.36, P = 0.001); the magnitude of reduction was similar between the sexes (11% (ES = 0.43) vs. 10% (ES = 0.31), respectively; P = 0.87). The small-moderate reduction in postprandial [TAG] after HIIR was similar between the sexes.  相似文献   

12.
The aim of this study was to examine whether perceptual variables can provide informational constraints for the goalkeepers to intercept the ball successfully in 1v1 dyads. Video images of 42 actions (1v1 in direct shots) were selected randomly from different matches and divided into conceded goals (n = 20) and saved actions (n = 22) to investigate interceptive actions of 20 goalkeepers in the English Premier League in season 2013–2014. Time to Contact (TTC) of the closing distance gap between shooter and goalkeeper was obtained by digitising actions in the 18-yard penalty box. Statistical analyses revealed that, in sequences of play resulting in an intercepted shot at goal, goalkeepers closed down outfield players in the X axis, whereas when a goal was conceded, there was a significantly delayed movement by goalkeepers toward the shooters in this plane. The results of canonical correlations showed that a decreasing distance between a shooter and goalkeeper, and accompanied reduction in relative interpersonal velocity followed a temporal pattern. Findings of this study showed how perception of key informational constraints on dyadic system relations, such as TTC, interpersonal distance and relative velocity, constrain elite goalkeepers’ interceptive actions, playing an important role in successful performance.  相似文献   

13.
Purpose: The purpose of this study was to investigate the influence of exercise intensity on postexercise supine and tilt baroreflex sensitivity (BRS). Method: Nine healthy, active men performed 2 conditions of interval cycling of 40% maximal work rate (WRmax) and 75% WRmax of matched work done and a control condition of no exercise in a counterbalanced order. BRS outcome measures were determined at preexercise and postexercise up to +24 hr in supine and tilt positions. R-R interval and blood pressure data were collected over consecutive 10-min periods and were analyzed by Fast Fourier transformation analysis. Results: A fully repeated analysis of variance revealed a significant interaction (p < .05) between time and condition in supine for BRSαLF, F(3, 134) = 5.19, p < .05, ES = .39, and BRSTFTG, F(3, 134) = 5.65, p < .05, ES = .41, and in tilt for BRSUpUp, F(3, 134) = 3.54, p < .05, ES = .31, BRSDownDown, F(3, 134) = 5.94, p < .05, ES = .43, BRSαLF, F(4, 134) = 6.23, p < .05, ES = .44, and BRSTFTG, F(4, 134) = 9.22, p < .05, ES = .54. There were significant differences (p < .05) between condition comparisons at +15 min and between control and 75% WRmax and between the 40% WRmax and 75% WRmax conditions at +60 min. At +15 min, BRS was lower in the 75% WRmax condition compared with the 40% WRmax condition and the control condition, and it was lower in the 40% WRmax condition than in the control condition. Conclusion: The findings demonstrate an intensity-dependent relationship in the BRS response following exercise.  相似文献   

14.
Abstract

This study compared technical actions, movements, heart rates and perceptual responses of selected and unselected youth rugby league players during matches (under-15 to under-17 age groups). The players’ movements and heart rates were assessed using 5 Hz Global Positioning Systems (GPSs), while their technical actions were analysed using video analysis. The maturity of each player was predicted before each season for statistical control. There were no differences (P > 0.05) between selected and unselected players in the under-15 or the under-17 age group for any variables. However, in the under-16 age group, the selected players (57.1 ± 11.9 min) played for longer than the unselected players (44.1 ± 12.3 min; P = 0.017; ES = 1.08 ± CI = 0.87), and covered more distance (5181.0 ± 1063.5 m cf. 3942.6 ± 1108.6 m, respectively; P = 0.012; ES = 1.14 ± CI = 0.88) and high-intensity distance (1808.8 ± 369.3 m cf. 1380.5 ± 367.7 m, respectively; P = 0.011; ES = 1.16 ± CI = 0.88). Although successful carries per minute was higher in the selected under-15 age group, there were no other differences (P > 0.05) in match performance relative to playing minutes between groups. Controlling for maturity, the less mature, unselected players from the under-16 age group performed more high-intensity running (P < 0.05). Our findings question the use of match-related measurements in differentiating between selected and unselected players, showing that later maturing players were unselected, even when performing greater high-intensity running during matches.  相似文献   

15.
Purpose: This study aimed to investigate the effects of water-based aerobic training on the lipid profile and lipoprotein lipase (LPL) levels in premenopausal women with dyslipidemia. Method: Forty women were randomly assigned to: aquatic training (WA; n = 20) or a control group (CG; n = 20). The WA group underwent 12 weeks of water-based interval aerobic training twice a week at intensities ranging from 9 to 15 on the Borg Scale of Perceived Exertion. Total cholesterol (TC), triglycerides (TG), high- (HDL) and low- (LDL) density lipoprotein, TC/HDL ratio, LPL levels, and peak oxygen consumption (VO2peak) were evaluated before and after 12 weeks in both groups. Results: The WA group elicited decreases in TC (9%; effect size [ES] = 0.69; 95% CI [0.05, 1.33]), LDL (16%; ES = 0.78; 95% CI [0.13, 1.42]), and the TC/HDL ratio (17%; ES = 1.13; 95% CI [0.46, 1.79]), as well as increases in VO2peak (10%; ES = 0.64; 95% CI [0.002, 1.27]) and HDL (10%; ES = 0.28; 95% CI [?0.35. 0.90]), without significant changes in TG (ES = 0.16; 95% CI [?0.46, 1.79]) and LPL (ES = 0.36; 95% CI [?0.27, 0.98]) levels. In the CG, no statistically significant changes in any of these variables were found (TC, ES = 0.19, 95% CI [?0.43, 0.82]; LDL, ES = 0.22, 95% CI [?0.40, 0.85]; HDL, ES = 0.05, 95% CI [?0.57, 0.67]; TG, ES = 0.09, 95% CI [?0.53, 0.71]; TC/HDL ratio, ES = 0.20, 95% CI [?0.42, 0.82]; LPL, ES = 0.02, 95% CI [?0.60, 0.64]; VO2peak, ES = 0.20, 95% CI [?0.42, 0.82]). Conclusion: Water-based interval aerobic training positively affected the lipid profile in premenopausal dyslipidemic women.  相似文献   

16.
Currently, very little is known about the impact of short- or long-haul air travel on the sleep and wellbeing of wheelchair basketball athletes. Eleven national wheelchair basketball athletes wore actigraphy monitors prior, during, and after air travel to the United Kingdom. Upon arrival, participants rated their subjective jet-lag, fatigue, and vigor. Individuals traveled to the United Kingdom from different locations in Australia, the United States, and Europe and were categorised according to travel length [LONG (up to 30.2 h) or SHORT (up to 6.5 h)]. Linear mixed models determined effects of travel length on sleep and subjective ratings of jet-lag, fatigue, and vigor. During competition, subjective fatigue and jet-lag were substantially higher (ES = 0.73; ±0.77) and (ES = 0.57; ±0.60), subjective vigor was lower (ES = 1.94; ±0.72), and get-up time was earlier (ES = 0.57; ±0.60) for LONG when compared to SHORT. Travelling greater distances by airplane had a larger effect on subjective ratings of jet-lag, fatigue and vigor, rather than sleep. Irrespective of travel group, sleep and subjective responses were compromised, reflecting the travel requirements, competition-mediated influences, and/or due to a change in environment.  相似文献   

17.
ABSTRACT

This study investigated changes in body composition in relation to training load determined using RPE and duration (sRPE), and its relationship with physical qualities over a preseason period. Sixteen professional academy players (age = 17.2 ± 0.7 years; stature = 179.9 ± 4.9 cm; body mass = 88.5 ± 10.1 kg) participated in the study. Body composition was assessed before and after each training phase and physical qualities assessed at the start and end of preseason. Across the whole preseason period, skinfold thickness, body fat percentage and fat mass were most likely lower (ES = ?0.73 to ?1.00), and fat free mass and lean mass were likely to most likely higher (ES = 0.31 to 0.40). Results indicated that the magnitude of change appeared phase-dependent (ES = ?0.05 to ?0.85) and demonstrated large individual variability. Changes in physical qualities ranged from unclear to most likely (ES = ?0.50 to 0.64). Small to moderate correlations were observed between changes in body composition, and TL with changes in physical qualities. This study suggests training phase and TL can influence a player’s body composition; that large inter-participant variability exists; and that body composition and TL are related to the change in physical qualities.  相似文献   

18.
ABSTRACT

To assess the impact of lower-leg muscle activity during the stance phase of running on the development of medial tibial stress syndrome (MTSS), in 123 healthy participants (18.2 ± 0.8 years), dynamic and static foot posture, and soleus and tibialis anterior muscle activity during the stance phase of running were measured before a 17-week track- and field-course. After the course, MTSS was identified in 20.5% of the participants. MTSS participants had a higher body mass (ES = 1.13), body mass index (BMI) (ES = 1.31), lower previous vigorous physical activity level (ES = 0.84) and VO2max (ES = 0.61), greater dynamic foot pronation (ES = 0.66), higher soleus peak EMG amplitude during the absorption (ES = 0.60) and propulsion phases (ES = 0.56) of running, and a history of MTSS (OR = 6.38) (p < 0.05). Stepwise logistic regression showed BMI, dynamic foot index, soleus peak EMG amplitude during propulsion, MTSS history and previous vigorous physical activity were predictors of MTSS. The model predicted 96.6% of the healthy participants and 56.5% of the MTSS participants and correctly classified 88.4% of overall cases. Coaches and sports-medicine professionals that screen for injury risk should consider adopting a comprehensive evaluation that includes these parameters.  相似文献   

19.
Abstract

The purpose of this study was to compare one-repetition maximum (1-RM) and muscle activity in three chest-press exercises with different stability requirements (Smith machine, barbell, and dumbbells). Twelve healthy, resistance-trained males (age 22.7 ± 1.7 years, body mass 78.6 ± 7.6 kg, stature 1.80 ± 0.06 m) were tested for 1-RM of the three chest-press exercises in counterbalanced order with 3–5 days of rest between the exercises. One-repetition maximum and electromyographic activity of the pectoralis major, deltoid anterior, biceps, and triceps brachii were recorded in the exercises. The dumbbell load was 14% less than that for the Smith machine (P ≤ 0.001, effect size [ES] = 1.05) and 17% less than that for the barbell (P ≤ 0.001, ES = 1.11). The barbell load was ～3% higher than that for the Smith machine (P = 0.016, ES = 0.18). Electrical activity in the pectoralis major and anterior deltoid did not differ during the lifts. Electrical activity in the biceps brachii increased with stability requirements (i.e. Smith machine <barbell <dumbbells; P ≤ 0.005; ES = 0.57, 1.46, and 2.00, respectively), while triceps brachii activity was reduced using dumbbells versus barbell (P = 0.007, ES = 0.73) and dumbbells versus Smith machine (P = 0.003, ES = 0.62). In conclusion, high stability requirements in the chest press (dumbbells) result in similar (pectoralis major and anterior deltoid), lower (triceps brachii) or higher (biceps brachii) muscle activity. These findings have implications for athletic training and rehabilitation.  相似文献   

20.
The aim of this study was to investigate the effects of maturation on power and sprint performance adaptations following 6 weeks of plyometric training in youth soccer players during pre-season. Sixty male soccer players were categorized into 3 maturity groups (Pre, Mid and Post peak height velocity [PHV]) and then randomly assigned to plyometric group and control group. Vertical jump, standing long jump, and 20-m sprint (with and without ball) tests were collected before- and after-intervention. After the intervention, the Pre, Mid and Post-PHV groups showed significant (P ≤ 0.05) and small to moderate effect size (ES) improvement in vertical jump (ES = 0.48; 0.57; 0.73), peak power output (E = 0.60; 0.64; 0.76), standing long jump (ES = 0.62; 0.65; 0.7), 20-m sprint (ES = ?0.58; ?0.66), and 20-m sprint with ball (ES = ?0.44; ?0.8; ?0.55) performances. The Post-PHV soccer players indicated greater gains than Pre-PHV in vertical jump and sprint performance after training (P ≤ 0.05). Short-term plyometric training had positive effects on sprinting and jumping-power which are important determinants of match-winning actions in soccer. These results indicate that a sixty foot contact, twice per week program, seems effective in improving power and sprint performance in youth soccer players.  相似文献   

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