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1.
Abstract

Elite badminton requires muscular endurance combined with appropriate maximal and explosive muscle strength. The musculature of the lower extremities is especially important in this context since rapid and forceful movements with the weight of the body are performed repeatedly throughout a match. In the present study, we examined various leg-strength parameters of 35 male elite badminton players who had been performing resistance exercises as part of their physical training for several years. The badminton players were compared with an age-matched reference group, the members of whom were physically active on a recreational basis, and to the same reference group after they had performed resistance training for 14 weeks. Maximal muscle strength of the knee extensor (quadriceps) and flexor muscles (hamstrings) was determined using isokinetic dynamometry. To measure explosive muscle strength, the contractile rate of force development was determined during maximal isometric muscle contractions. In general, the badminton players showed greater maximal muscle strength and contractile rate of force development than the reference group: mean quadriceps peak torque during slow concentric contraction: 3.69 Nm · kg?1, s=0.08 vs. 3.26 Nm · kg?1, s=0.8 (P<0.001); mean hamstring peak torque during slow concentric contraction: 1.86 Nm · kg?1, s=0.04 vs. 1.63 Nm · kg?1, s=0.04 (P<0.001); mean quadriceps rate of force development at 100 ms: 24.4 Nm · s?1·kg?1, s=0.5 vs. 22.1 Nm·s?1 · kg?1, s=0.6 (P<0.05); mean hamstring rate of force development at 100 ms: 11.4 Nm · s?1·kg?1, s=0.3 vs. 8.9 Nm · s?1 · kg?1, s=0.4 (P<0.05). However, after 14 weeks of resistance training the reference group achieved similar isometric and slow concentric muscle strength as the badminton players, although the badminton players still had a higher isometric rate of force development and muscle strength during fast (240° · s?1) quadriceps contractions. Large volumes of concurrent endurance training could have attenuated the long-term development of maximal muscle strength in the badminton players. The badminton players had a higher contractile rate of force development than the reference group before and after resistance training. Greater explosive muscle strength in the badminton players might be a physiological adaptation to their badminton training.  相似文献   

2.
The purpose of this study was to investigate the influence of sex and fatigue on knee extensor peak torque (PT), muscle stiffness (MS) of the vastus lateralis (VL) and knee joint musculoarticular stiffness (MAS) in young adults. Twenty-two male and 22 female recreational athletes participated. Males were characterised by higher relaxed [pre-: males 364.43 (52.00) N · m–1, females 270.27 (37.25) N · m–1; post-: males 446.75 (83.27) N · m–1, females 307.39 (38.58) N · m–1] and contracted [pre-: males 495.07 (71.04) N · m–1, females 332.34 (85.42) N · m–1; post-: males 546.37 (90.74) N · m–1, females 349.21 (85.55) N · m–1] MS of the VL, and knee joint MAS [pre-: males 1450.11 (507.98) N · m–1, females 1027.99 (227.33) N · m–1; post-: males 1345.81 (404.90) N · m–1, females 952.78 (192.38) N · m–1] than females pre- and post-fatigue. A similar finding was observed in pre-fatigue normalised knee extensor PT [pre-: males 2.77 (0.42) N · m kg–1, females 2.41 (0.40) N · m kg–1, post-: males 2.53 (0.54) N · m kg–1, females 2.26 (0.44) N · m kg–1]. After the fatigue protocol, normalised knee extensor PT and knee joint MAS decreased, whilst relaxed and contracted MS of the VL increased in both sexes. These observed differences may contribute to the higher risk of knee injury in females and following the onset of fatigue.  相似文献   

3.
Purpose: The main purpose of this study was to investigate the influence of fatigue on musculoarticular stiffness (MAS) of the ankle joint across sexes. Methods: Twenty-seven males and 26 females participated in the study. After baseline assessment of MAS and related variables, localised fatigue was induced in triceps surae using the standing heel-rise test during which the subjects were instructed to lift and drop the heel at a frequency of 0.5?Hz. When subjects were unable to continue due to exhaustion the test was terminated and another MAS test was performed soon after. Results: Significant higher triceps surae MAS was found in men compared to women (p?p??1 and from 14.5 to 13.9?KN?m?1 in men and women, respectively. Percentage changes revealed, however, that in relative terms the changes in all the variables evaluated were similar (p?>?.01) between sexes, with MAS less than 5%. Conclusion: Despite the sex-related differences at baseline, fatigue seems to affect biomechanical properties of the ankle joint similarly in men and women.  相似文献   

4.
Abstract

Leg stiffness is a modifiable mechanical property that may be related to soft tissue injury risk. The purpose of this study was to examine mean leg stiffness and bilateral differences in leg stiffness across an entire professional Australian Football League (AFL) season, and determine whether this parameter was related to the incidence of lower body soft tissue injury. The stiffness of the left and right legs of 39 professional AFL players (age 24.4 ± 4.4 years, body mass 87.4 ± 8.1 kg, stature 1.87 ± 0.07 m) was measured using a unilateral hopping test at least once per month throughout the season. Injury data were obtained directly from the head medical officer at the football club. Mean leg stiffness and bilateral differences in leg stiffness were compared between the injured and non-injured players. There was no difference between the season mean leg stiffness values for the injured (219.3 ± 16.1 N · m?1 · kg?1) and non-injured (217.4 ± 14.9 N · m?1 · kg?1; P = 0.721) groups. The injured group (7.5 ± 3.0%) recorded a significantly higher season mean bilateral difference in leg stiffness than the non-injured group (5.5 ± 1.3%; P = 0.05). A relatively high bilateral difference in leg stiffness appears to be related to the incidence of soft tissue injury in Australian football players. This information is of particular importance to medical and conditioning staff across a variety of sports.  相似文献   

5.
Abstract

The present study aimed to establish whether 2 weeks of high-intensity interval training would have a beneficial effect on aerobic fitness, fat oxidation, blood pressure and body mass index (BMI) in healthy adolescent boys. Ten adolescent boys (15.1 ± 0.3 years, 1.3 ± 0.2 years post-estimated peak height velocity) completed six sessions of Wingate-style high-intensity interval training over a 2-week period. The first session consisted of four sprints with training progressed to seven sprints in the final session. High-intensity interval training had a beneficial effect on maximal O2 uptake (mean change, ±90% confidence intervals: 0.19 L · min?1, ±0.19, respectively), on the O2 uptake at the gas exchange threshold (0.09 L · min?1, ±0.13) and on the O2 cost of sub-maximal exercise (–0.04 L · min?1, ±0.04). A beneficial effect on the contribution of lipid (0.06 g · min?1, ±0.06) and carbohydrate (–0.23 g · min?1, ±0.14) oxidation was observed during sub-maximal exercise, but not for the maximal rate of fat oxidation (0.04 g · min?1, ±0.08). Systolic blood pressure (1 mmHg, ±4) and BMI (0.1 kg · m2, ±0.1) were not altered following training. These data demonstrate that meaningful changes in health outcomes are possible in healthy adolescent boys after just six sessions of high-intensity interval training over a 2-week period.  相似文献   

6.
Abstract

In this study, we investigated the effect of biological maturation on maximal oxygen uptake ([Vdot]O2max) and ventilatory thresholds (VT1 and VT2) in 110 young soccer players separated into pubescent and post-pubescent groups.. Maximal oxygen uptake and [Vdot]O2 corresponding to VT1 and VT2 were expressed as absolute values, ratio standards, theoretical exponents, and experimentally observed exponents. Absolute [Vdot]O2 (ml · min?1) was different between groups for VT1, VT2, and [Vdot]O2max. Ratio standards (ml · kg?1 · min?1) were not significantly different between groups for VT1, VT2, and [Vdot]O2max. Theoretical exponents (ml · kg?0.67 · min?1 and ml · kg?0.75 · min?1) were not properly adjusted for the body mass effects on VT1, VT2, and [Vdot]O2max. When the data were correctly adjusted using experimentally observed exponents, VT1 (ml · kg?0.94 · min?1) and VT2 (ml · kg?0.95 · min?1) were not different between groups. The experimentally observed exponent for [Vdot]O2max (ml · kg?0.90 · min?1) was different between groups (P = 0.048); however, this difference could not be attributed to biological maturation. In conclusion, biological maturation had no effect on VT1, VT2 or [Vdot]O2max when the effect of body mass was adjusted by experimentally observed exponents. Thus, when evaluating the physiological performance of young soccer players, allometric scaling needs to be taken into account instead of using theoretical approaches.  相似文献   

7.
Abstract

This study was conducted to determine if the Polar FT40 could accurately track changes in maximal oxygen consumption (VO2max) in a group of female soccer players. Predicted VO2max (pVO2max) via the Polar FT40 and observed VO2max (aVO2max) from a maximal exercise test on a treadmill were determined for members of a collegiate soccer team (n = 20) before and following an 8-week endurance training protocol. Predicted (VO2max and aVO2max measures were compared at baseline and within 1 week post-training. Change values (i.e., the difference between pre to post) for each variable were also determined and compared. There was a significant difference in aVO2max (pre = 43.6 ± 2.4 ml · kg · min?1, post = 46.2 ± 2.4 ml · kg · min?1, P < 0.001) and pVO2max (pre = 47.3 ± 5.3 ml · kg · min?1, post = 49.7 ± 6.2 ml · kg · min?1, P = 0.009) following training. However, predicted values were significantly greater at each time point compared to observed values (P < 0.001 at pre and P = 0.008 at post). Furthermore, there was a weak correlation between the change in aVO2max and the change in pVO2max (r = 0.18, P = 0.45). The Polar FT40 does not appear to be a valid method for predicting changes in individual VO2max following 8 weeks of endurance training in female collegiate soccer players.  相似文献   

8.
Abstract

Twenty-four players from the 1st/2nd (elite) and 24 players from the 3rd/4th (non-elite) university football teams were recruited to evaluate the Loughborough Soccer Passing Test (LSPT) and Loughborough Soccer Shooting Test (LSST) as tools to assess soccer skill. The LSPT requires players to complete 16 passes as quickly as possible. The LSST requires players to pass, control, and shoot the ball to targets on a full-sized goal. Participants completed two main trials each separated by at least one day. During both trials, the participants were given practice efforts before recording the mean of the next two (LSPT) or 10 (LSST) attempts as the performance score. For the LSPT, the mean time taken, added penalty time, and overall performance time were less in the elite players (elite: 43.6 s, s = 3.8; non-elite: 52.5 s, s = 7.4; P = 0.0001). For the LSST, there was no difference in the mean points scored per shot between groups (elite: 1.34, s = 0.46; non-elite: 1.28, s = 0.53). However, the elite players had higher mean shot speed (elite: 80 km · h?1, s = 4.5; non-elite: 74 km · h?1, s = 4.2; P < 0.0001) and performed each shot sequence faster (elite: 7.87 s, s = 0.29; non-elite: 8.07 s, s = 0.35; P = 0.037) than the non-elite players. Performance on both tests was more repeatable in elite players. In conclusion, the LSPT and LSST are valid and reliable protocols to assess differences in soccer skill performance.  相似文献   

9.
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10.
Strenuous physical exercise of the limb muscles commonly results in damage, especially when that exercise is intense, prolonged and includes eccentric contractions. Many factors contribute to exercise-induced muscle injury and the mechanism is likely to differ with the type of exercise. Competitive sports players are highly susceptible to this type of injury. AM3 is an orally administered immunomodulator that reduces the synthesis of proinflammatory cytokines and normalizes defective cellular immune fractions. The ability of AM3 to prevent chronic muscle injury following strenuous exercise characterized by eccentric muscle contraction was evaluated in a double-blind and randomized pilot study. Fourteen professional male volleyball players from the First Division of the Spanish Volleyball League volunteered to take part. The participants were randomized to receive either placebo (n?=?7) or AM3 (n?=?7). The physical characteristics (mean±s) of the placebo group were as follows: age 25.7±2.1 years, body mass 87.2±4.1?kg, height 1.89±0.07?m, maximal oxygen uptake 65.3±4.2?ml?·?kg?1?·?min?1. Those of the AM3 group were as follows: age 26.1±1.9 years, body mass 85.8±6.1?kg, height 1.91±0.07?m, maximal oxygen uptake 64.6±4.5?ml?·?kg?1?·?min?1. All participants were evaluated for biochemical indices of muscle damage, including concentrations of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, creatine kinase (CK) and its MB fraction (CK-MB), myoglobin, lactate dehydrogenase, urea, creatinine and γ-glutamyltranspeptidase, both before and 30 days after treatment (over the peak of the competitive season). In the placebo group, competitive exercise (i.e. volleyball) was accompanied by significant increases in creatine kinase (494±51 to 560±53?IU?·?l?1, P?<?0.05) and myoglobin (76.8±2.9 to 83.9±3.1?μg?·?l?1, P?<?0.05); aspartate aminotransferase (30.8±3.0 to 31.1±2.9?IU?·?l?1) and lactate dehydrogenase (380±31 to 376±29?IU?·?l?1) were relatively unchanged after the 30 days maximum effort. AM3 not only inhibited these changes, it led to a decrease from baseline serum concentrations of creatine kinase (503±49 to 316±37?IU?·?l?1, P?<?0.05) and myoglobin (80.1±3.2 to 44.1±2.6?IU?·?l?1, P?<?0.05), as well as aspartate aminotransferase (31.1±3.3 to 26.1±2.7?IU?·?l?1, P?<?0.05) and lactate dehydrogenase (368±34 to 310±3?IU?·?l?1, P?<?0.05). The concentration of CK-MB was also significantly decreased from baseline with AM3 treatment (11.6±1.2 to 5.0±0.7?IU?·?l?1, P?<?0.05), but not with placebo (11.4±1.1 to 10.8±1.4?IU?·?l?1). In conclusion, the use of immunomodulators, such as AM3, by elite sportspersons during competition significantly reduces serum concentrations of proteins associated with muscle damage.  相似文献   

11.
Abstract

This study examined the relationship between intensity of training and changes in hydration status, core temperature, sweat rate and composition and fluid balance in professional football players training in the heat. Thirteen professional football players completed three training sessions; “higher-intensity” (140 min; HI140), “lower-intensity” (120 min; LI120) and “game-simulation” (100 min; GS100). Movement demands were measured by Global Positioning System, sweat rate and concentration were determined from dermal patches and body mass change. Despite similar environmental conditions (26.9 ± 0.1°C and 65.0 ± 7.0% relative humidity [Rh]), higher relative speeds (m · min?1) and increased perceptions of effort and thermal strain were observed in HI140 and GS100 compared with LI120 (P < 0.05). Significantly (P < 0.05) greater sweat rate (L · h?1) and electrolyte losses (g) were observed in HI140 and GS100 compared with LI120. Rate of rise in core temperature was correlated with mean speed (r = 0.85), session rating of perceived exertion (sRPE) (r = 0.61), loss of potassium (K+) (r = 0.51) sweat rate (r = 0.49), and total sweat loss (r = 0.53), with mean speed the strongest predictor. Sodium (Na+) (r = 0.39) and K+ (r = 0.50) losses were associated with total distance covered. In hot conditions, individualised rehydration practices should be adopted following football training to account for differences in sweat rate and electrolyte losses in response to intensity and overall activity within a session.  相似文献   

12.
The purpose of this paper is to provide a comprehensive review of the science of rugby league football at all levels of competition (i.e. junior, amateur, semi-professional, professional), with special reference to all discipline-specific scientific research performed in rugby league (i.e. physiological, psychological, injury epidemiology, strength and conditioning, performance analysis). Rugby league football is played at junior and senior levels in several countries worldwide. A rugby league team consists of 13 players (6 forwards and 7 backs). The game is played over two 30?–?40 min halves (depending on the standard of competition) separated by a 10?min rest interval. Several studies have documented the physiological capacities and injury rates of rugby league players. More recently, studies have investigated the physiological demands of competition. Interestingly, the physiological capacities of players, the incidence of injury and the physiological demands of competition all increase as the playing standard is increased. Mean blood lactate concentrations of 5.2, 7.2 and 9.1?mmol?·?l?1 have been reported during competition for amateur, semi-professional and professional rugby league players respectively. Mean heart rates of 152 beats?·?min?1 (78% of maximal heart rate), 166 beats?·?min?1 (84% of maximal heart rate) and 172 beats?·?min?1 (93% of maximal heart rate) have been recorded for amateur, semi-professional and junior elite rugby league players respectively. Skill-based conditioning games have been used to develop the skill and fitness of rugby league players, with mean heart rate and blood lactate responses during these activities almost identical to those obtained during competition. In addition, recent studies have shown that most training injuries are sustained in traditional conditioning activities that involve no skill component (i.e. running without the ball), whereas the incidence of injuries while participating in skill-based conditioning games is low. Collaborative research among the various sport science disciplines is required to identify strategies to reduce the incidence of injury and enhance the performance of rugby league players. An understanding of the movement patterns and physiological demands of different positions at all standards of competition would allow the development of strength and conditioning programmes to meet the precise requirements of these positions. Finally, studies investigating the impact of improvements in physiological capacities (including the effect of different strength and conditioning programmes) on rugby league playing performance are warranted.  相似文献   

13.
Abstract

The aim of this study was to determine sprint profiles of professional female soccer players and evaluate how various speed thresholds impact those outcomes. Seventy-one professional players competing in full matches were assessed repeatedly during 12 regular season matches using a Global Positioning System (GPS). Locomotion ≥18 km · h?1 was defined as sprinting and each event was classified into: Zone 1: 18.0–20.9 km· h?1; Zone 2: 21.0–22.9 km · h?1; Zone 3: 23.0–24.9 km · h?1 and Zone 4: >25 km · h?1. Outcomes included: duration (s), distance (m), maximum speed (km · h?1), duration since previous sprint (min) and proportion of total sprint distance. In total 5,019 events were analysed from 139 player-matches. Mean sprint duration, distance, maximum speed and time between sprints were 2.3 ± 1.5 s, 15.1 ± 9.4 m, 21.8 ± 2.3 km· h?1, and 2.5 ± 2.5 min, respectively. Mean sprint distances were 657 ± 157, 447 ± 185, and 545 ± 217 m for forwards, midfielders and defenders, respectively (P ≤ 0.046). Midfielders had shorter sprint duration (P = 0.023), distance (P ≤ 0.003) and maximum speed (P < 0.001), whereas forwards performed more sprints per match (43 ± 10) than midfielders (31 ± 11) and defenders (36 ± 12) (P ≤ 0.016). Forty-five percent, 29%, 15%, and 11% of sprints occurred in sprint Zones 1, 2, 3 and 4, respectively. This group of professional female soccer players covered 5.3 ± 2.0% of total distance ≥18 km · h?1 with positional differences and percent decrements distinct from other previously identified elite players. These data should guide the development of high intensity and sprint thresholds for elite-standard female soccer players.  相似文献   

14.
Abstract

The purpose of this study was to investigate the eccentric torque–velocity and power–velocity relationships of the elbow flexors. Forty recreationally trained individuals (20 men, 20 women) performed maximal eccentric actions at each of five different velocities (1.04 rad · s?1, 2.09 rad · s?1, 3.14 rad · s?1, 4.18 rad · s?1, and 5.23 rad · s?1, in random order) and maximal isometric actions on a Biodex isokinetic dynamometer. A 2×6 (sex×velocity) mixed-factor repeated-measures analysis of variance (ANOVA) was used to assess peak elbow flexor torque during the eccentric and isometric actions. There was no interaction, but there were significant main effects for sex and velocity. Pairwise comparisons demonstrated that values for men were significantly (P<0.05) higher than those for women at all speeds. Furthermore, torques for both sexes were significantly less at 3.14 rad · s?1 (men: 103.94±28.28 N · m; women: 49.24±11.69 N · m) than at 4.18 rad · s?1 (men: 106.39±30.23 N · m; women: 52.77±11.31 N · m) and 5.23 rad · s?1 (men: 108.75±28.59 N · m; women: 53.3±11.67 N · m), while isometric torque was significantly less than at all other speeds (men: 98.66±28.0 N · m; women: 45.25±11.15 N · m). A 2×5 (sex×velocity) mixed-factor repeated-measures ANOVA was used to assess peak eccentric elbow flexor power. There were significant main effects for sex and velocity. Pairwise comparisons demonstrated that values for men were significantly higher than those for women at all speeds. Pairwise comparisons for velocity indicated that peak eccentric power increased across all speeds from 1.04 rad · s?1 (men: 110.44±32.56 W; women 54.36±13.05 W) to 5.23 rad · s?1 (men: 569.46±149.73 W; women: 279.10±61.10 W). These results demonstrate that an increase in velocity had little or no effect on eccentric elbow flexor torque, while eccentric elbow flexor power increased significantly with increases in velocity.  相似文献   

15.
Abstract

The aims of this study were to establish the physical and physiological attributes of elite and sub-elite Malaysian male badminton players and to determine whether these attributes discriminate elite players from sub-elite players. Measurements and tests of basic anthropometry, explosive power, anaerobic recovery capacity, badminton-specific movement agility, maximum strength, and aerobic capacity were conducted on two occasions, separated by at least one day. The elite (n = 12) and sub-elite (n = 12) players' characteristics were, respectively: mean age 24.6 years (s = 3.7) and 20.5 years (s = 0.7); mass 73.2 kg (s = 7.6) and 62.7 kg (s = 4.2); stature 1.76 m (s = 0.07) and 1.71 m (s = 0.05); body fat 12.5% (s = 4.8) and 9.5% (s = 3.4); estimated VO2max 56.9 ml · kg?1 · min?1 (s = 3.7) and 59.5 ml · kg?1 · min?1 (s = 5.2). The elite players had greater maximum absolute strength in one-repetition maximum bench press (P = 0.015) compared with the sub-elite players. There were significant differences in instantaneous lower body power estimated from vertical jump height between the elite and sub-elite groups (P < 0.01). However, there was no significant difference between groups in shuttle run tests and on-court badminton-specific movement agility tests. Our results show that elite Malaysian male badminton players are taller, heavier, and stronger than their sub-elite counterparts. The test battery, however, did not allow us to discriminate between the elite and sub-elite players, suggesting that at the elite level tactical knowledge, technical skills, and psychological readiness could be of greater importance.  相似文献   

16.
The aim of this study was to develop an exercise protocol to simulate tennis matchplay on a 'category 2' surface. Match analyses were used to form the basis for the design of the protocol. The protocol involved playing against a tennis ball serving machine. Part A of the protocol comprised 92 min 46 s of simulated tennis matchplay; Part B consisted of continuous hitting to the point of 'volitional fatigue' or when the required hitting frequency for two consecutive ball feeds could no longer be maintained. Ten elite tennis players (5 males, 5 females) volunteered to participate in the study, which was performed on an indoor tennis court (Matchplay?, En-Tout-Cas)?. Their age, body mass and estimated maximal oxygen uptake were as follows: males, 21.7±1.0 years, 73.6±2.6 kg and 58.0±1.7 ml?·?kg?1?·?min?1, respectively; females, 21.9±1.3 years, 62.3±2.0 kg and 42.2±0.7 ml?·?kg?·?min?1, respectively (mean±). Heart rate, change in body mass and time to volitional fatigue were monitored. The heart rate responses of the participants to the simulated matchplay (range: 140-157 beats?·?min?1, 73-81% peak heart rate) were consistent with the results of previous studies, for 'actual' matchplay. This protocol was successful in simulating similar physiological responses in Part A to 'actual' matchplay on a 'category 2' surface, in a controlled environment; it was also a sensitive evaluation tool of skilled performance in Part B. The current protocol may be used as a baseline protocol for studying the influence of, for example, training and dietary intervention on performance.  相似文献   

17.
Abstract

Individuals with impaired glucose tolerance (IGT) are at greater risk of developing diabetes than in normoglycaemia. The aim of this study was to examine the effects of 12-weeks exercise training in obese humans with IGT. Eleven participants (6 males and 5 females; 49±9 years; mean Body Mass Index (BMI) 32.4 kg · m?2), completed a 12-week brisk walking intervention (30 min per day, five days a week (d · wk?1), at 65% of age-predicted maximal heart rate (HRmax). Anthropometric measurements, dietary intake, pulse wave velocity (PWV, to determine arterial stiffness) and blood pressure (BP) were examined at baseline and post intervention. Fasting blood glucose, glycosylated haemoglobin, insulin, blood lipids, indices of oxidative stress and inflammation (lipid hydroperoxides; superoxide dismutase; multimeric adiponectin concentration and high-sensitivity C-reactive protein) were also determined. Post intervention, PWV (9.08±1.27 m · s?1 vs. 8.39±1.21 m · s?1), systolic BP (145.4±14.5 vs. 135.8±14.9 mmHg), triglycerides (1.52±0.53 mmol . L?1 vs. 1.31±0.54 mmol . L?1), lipid hydroperoxides (1.20±0.47 μM · L?1 vs. 0.79±0.32 μM · L?1) and anthropometric measures decreased significantly (P < 0.05). Moderate intensity exercise training improves upper limb vascular function in obese humans with IGT, possibly by improving triglyceride metabolism, which may subsequently reduce oxidative stress. These changes were independent of multimeric adiponectin modification and alterations in other blood biomarkers.  相似文献   

18.
Abstract

This study aimed to examine the effects of application of kinaesthetic tapes on plantarflexor muscle performance. We hypothesised that taping of the triceps surae muscle would improve plantarflexor muscle strength and endurance with no significant effect on drop jump performance. Using a repeated-measures design, all performance measures were obtained in 24 volunteers on two separate occasions: without tapes and after application of kinaesthetic tapes. Performance tests included measurements of isometric plantarflexor muscle strength and the associated electromyographic activity of the gastrocnemius muscle, an isokinetic fatigue resistance test (30 contractions at 180° · s?1) and assessments of drop jump performance. The taping-intervention was associated with an increase in gastrocnemius electromyographic activity. However, significant increases in isometric strength were only found at fully dorsiflexed ankle positions (+12% at ?20°). Strength gains were negatively correlated to baseline strength (r = ?.58). The intervention did not affect the results of the isokinetic fatigue and drop jump tests. The application of kinaesthetic tapes over the triceps surae muscle promotes an increase in isometric strength and gastrocnemius muscle activity. Our data suggest that these effects are joint-angle dependent and more prominent in weaker individuals. By contrast, the taping-intervention improves neither drop jump performance nor muscular endurance.  相似文献   

19.
Recreational soccer is an effective health-promoting activity, but it is unclear how different game formats influence internal and external load. Thus, to be able to advise how to maximise the outcome of recreational football, we examined movement pattern and physiological response in 11 untrained men (32.6 ± 6.7 yrs, 23.3 ± 4.9 fat%, 43.4 ± 5.3 ml·min?1·kg?1) during three football sessions comprising 4 × 12 min of 3v3, 5v5 or 7v7 with a constant pitch size of 20 × 40 m. Movement pattern, heart rate (HR), blood lactate and RPE were measured during and after the 12-min periods. Greater (P < 0.05) total distance and high-speed distance was covered during 3v3 than 5v5 (14 and 30%) and 7v7 (15 and 75%). Mean HR was higher in 3v3 (85.7 ± 5.7%HRmax) and 5v5 (84.2 ± 5.1%HRmax) than in 7v7 (80.7 ± 4.6%HRmax, P < 0.05) and percentage time >90%HR was higher in 3v3 (43 ± 18%, P < 0.05) than in 5v5 (28 ± 21%) and 7v7 (18 ± 14%). Blood lactate was higher in 3v3 (7.4 ± 2.7 mmol·l?1) than in 7v7 (4.5 ± 2.2 mmol·l?1, P < 0.001) but not in 5v5 (6.1 ± 2.1 mmol·l?1, P = 0.061). RPE was higher in 3v3 (6.7 ± 2.3, P < 0.01) than in 5v5 (5.2 ± 2.2) and 7v7 (4.3 ± 2.3). In conclusion, higher external and internal load was found with fewer players, when the pitch size is fixed.  相似文献   

20.
Abstract

In this study, we investigated the age-related differences in repeated-sprint ability and blood lactate responses in 134 youth football players. Players from the development programme of a professional club were grouped according to their respective under-age team (U-11 to U-18). Following familiarization, the participants performed a repeated-sprint ability test [6 × 30-m sprints 30 s apart, with active recovery (2.0–2.2 m · s?1) between sprints]. The test variables were total time, percent sprint decrement, and post-test peak lactate concentration. Total time improved from the U-11 to U-15 age groups (range 33.15 ± 1.84 vs. 27.25 ± 0.82 s), whereas no further significant improvements were evident from U-15 to U-18. No significant differences in percent sprint decrement were reported among groups (range 4.0 ± 1.0% to 5.5 ± 2.1%). Post-test peak lactate increased from one age group to the next (range 7.3 ± 1.8 to 12.6 ± 1.6 mmol · l?1), but remained constant when adjusted for age-related difference in body mass. Peak lactate concentration was moderately correlated with sprint time (r = 0.70, P > 0.001). Our results suggest that performance in repeated-sprint ability improves during maturation of highly trained youth football players, although a plateau occurs from 15 years of age. In contrast to expectations based on previous suggestions, percent sprint decrement during repeated sprints did not deteriorate with age.  相似文献   

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