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1.
Exercise intensity and metabolic response in singles tennis 总被引：5，自引：0，他引：5
Christmass MA Richmond SE Cable NT Arthur PG Hartmann PE 《Journal of sports sciences》1998,16(8):739-747
The aim of this study was to determine exercise intensity and metabolic response during singles tennis play. Techniques for assessment of exercise intensity were studied on-court and in the laboratory. The on-court study required eight State-level tennis players to complete a competitive singles tennis match. During the laboratory study, a separate group of seven male subjects performed an intermittent and a continuous treadmill run. During tennis play, heart rate (HR) and relative exercise intensity (72 +/- 1.9% VO2max; estimated from measurement of heart rate) remained constant (83.4 +/- 0.9% HRmax; mean +/- s(x)) after the second change of end. The peak value for estimated play intensity (1.25 +/- 0.11 steps x s(-1); from video analysis) occurred after the fourth change of end (P< 0.005). Plasma lactate concentration, measured at rest and at the change of ends, increased 175% from 2.13 +/- 0.32 mmol x l(-1) at rest to a peak 5.86 +/- 1.33 mmol x l(-1) after the sixth change of end (P < 0.001). A linear regression model, which included significant terms for %HRmax (P< 0.001), estimated play intensity (P < 0.001) and subject (P < 0.00), as well as a %HRmax subject interaction (P < 0.05), accounted for 82% of the variation in plasma lactate concentration. During intermittent laboratory treadmill running, % VO2peak estimated from heart rate was 17% higher than the value derived from the measured VO2 (79.7 +/- 2.2% and 69.0 +/- 2.5% VO2peak respectively; P< 0.001). The %VO2peak was estimated with reasonable accuracy during continuous treadmill running (5% error). We conclude that changes in exercise intensity based on measurements of heart rate and a time-motion analysis of court movement patterns explain the variation in lactate concentration observed during singles tennis, and that measuring heart rate during play, in association with preliminary fitness tests to estimate VO2, will overestimate the aerobic response. 相似文献
2.
A notational analysis of singles events at all four Grand Slam tournaments between 1997 and 1999 was conducted to determine the influence of the sex of the player and court surface on elite tennis strategy. Rallies of 7.1 ± 2.0 s in women's singles were significantly longer than those in men's singles (5.2 ± 1.8 s P < 0.001). Rallies of 6.3 ± 1.8 s at the Australian Open, 7.7 ± 1.7 s at the French Open, 4.3 ± 1.6 s at Wimbledon and 5.8 ± 1.9 s at the US Open were recorded. Rallies were significantly longer at the French Open than at any other tournament ( P < 0.05) and significantly shorter at Wimbledon than at any other tournament ( P < 0.05). In women's singles, 52.8 ± 12.4% of points were baseline rallies, significantly more than in men's singles (28.6 ± 19% P < 0.001). The proportion of baseline rallies played at the French Open (51.9 ± 14.2% of points) was significantly greater than at the Australian Open (46.6 ± 12.5%), Wimbledon (19.7 ± 19.4%) and the US Open (35.4 ± 19.5% P < 0.05). The results show that both the sex of the player and surface of the court have a significant influence on the nature of singles tennis at Grand Slam tournaments. 相似文献
3.
Conconi et al. (1982) reported that an observed deviation from linearity in the heart rate-running velocity relationship determined during a field test in runners coincided with the ‘lactate threshold’. The aim of this study was to assess the validity of the original Conconi test using conventional incremental and constant-load laboratory protocols. Fourteen trained male distance runners (mean ± s : age 22.6 ±3.4 years; body mass 67.6±4.8 kg; peak [Vdot] O 2 66.3 ± 4.7 ml kg -1 min -1) performed a standard multi-stage test for determination of lactate turnpoint and a Conconi test on a motorized treadmill. A deviation from linearity in heart rate was observed in nine subjects. Significant differences were found to exist between running velocity at the lactate turnpoint (4.39 ± 0.20 ms -1) and at deviation from linear heart rate (5.08 ± 0.25 ms -1) (P < 0.01), and between heart rate at the lactate turnpoint (172 ± 10 beats min -1) and at deviation from linearity (186 ± 9 beats min -1) (P < 0.01). When deviation of heart rate from linearity was evident, it occurred at a systematically higher intensity than the lactate turnpoint and at approximately 95% of maximum heart rate. These results were confirmed by the physiological responses of seven subjects, who performed two constant-velocity treadmill runs at 0.14 ms -1 below the running velocity at the lactate turnpoint and that at which the heart rate deviated from linearity. For the lactate turnpoint trial, the prescribed 30 min exercise period was completed by all runners (terminal blood lactate concentration of 2.4 ± 0.5 mM ), while the duration attained in the trial for which heart rate deviated from linearity was 15.9 ± 6.7 min (terminal blood lactate concentration of 8.1 ± 1.8 mM). We concluded that the Conconi test is invalid for the non-invasive determination of the lactate turnpoint and that the deviation of heart rate from linearity represents the start of the plateau at maximal heart rate, the expression of which is dependent upon the specifics of the Conconi test protocol. 相似文献
4.
Sixteen female games players completed 15 min of intermittent exercise on a treadmill. The speed and incline of the treadmill were varied to elicit a similar heart rate response to that found during women's hockey match‐play. The mean heart rate response was 169 ± 8 beats min‐1 and the mean work:rest ratio was 1:1.7. Oxygen uptake was estimated by applying the oxygen cost determined from an individual's heart rate‐oxygen uptake regression equation to the average heart rate each 5 s during the intermittent exercise. A second esimation of oxygen uptake was made from a time‐motion analysis by assigning a specific oxygen cost to each discrete movement during the intermittent exercise protocol. The true oxygen cost was calculated from the analysis of the expired gas. The heart rate analysis overestimated the true cost by a mean of 4.3 ± 5.3% (0.09 ± 0.11 1 min‐1), and the time‐motion analysis underestimated the true value by a mean of 15.7 ± 6.3% (0.34 ± 0.15 1 min‐1). There was a significant difference (P < 0.01) between the true value and both the estimates. It was concluded that heart rate analysis gives a much better indication of oxygen uptake during intermittent activity than time‐motion analysis. 相似文献
5.
The aims of this study were: (1) to identify the exercise intensity that corresponds to the maximal lactate steady state in adolescent endurance-trained runners; (2) to identify any differences between the sexes; and (3) to compare the maximal lactate steady state with commonly cited fixed blood lactate reference parameters. Sixteen boys and nine girls volunteered to participate in the study. They were first tested using a stepwise incremental treadmill protocol to establish the blood lactate profile and peak oxygen uptake ([Vdot]O2). Running speeds corresponding to fixed whole blood lactate concentrations of 2.0, 2.5 and 4.0?mmol?·?l?1 were calculated using linear interpolation. The maximal lactate steady state was determined from four separate 20-min constant-speed treadmill runs. The maximal lactate steady state was defined as the fastest running speed, to the nearest 0.5?km?·?h?1, where the change in blood lactate concentration between 10 and 20?min was?<0.5?mmol?·?l?1. Although the boys had to run faster than the girls to elicit the maximal lactate steady state (15.7 vs 14.3?km?·?h?1, P?<0.01), once the data were expressed relative to percent peak [Vdot]O2 (85 and 85%, respectively) and percent peak heart rate (92 and 94%, respectively), there were no differences between the sexes (P?>0.05). The running speed and percent peak [Vdot]O2 at the maximal lactate steady state were not different to those corresponding to the fixed blood lactate concentrations of 2.0 and 2.5?mmol?·?l?1 (P?>0.05), but were both lower than those at the 4.0?mmol?·?l?1 concentration (P?<0.05). In conclusion, the maximal lactate steady state corresponded to a similar relative exercise intensity as that reported in adult athletes. The running speed, percent peak [Vdot]O2 and percent peak heart rate at the maximal lactate steady state are approximated by the fixed blood lactate concentration of 2.5?mmol?·?l?1 measured during an incremental treadmill test in boys and girls. 相似文献
6.
In this study, we assessed the performance of trained senior (n = 6) and veteran (n = 6) cyclists (mean age 28 years, s = 3 and 57 years, s = 4 respectively). Each competitor completed two cycling tests, a ramped peak aerobic test and an indoor 16.1-km time-trial. The tests were performed using a Kingcycle ergometer with the cyclists riding their own bicycle fitted with an SRM powermeter. Power output, heart rate, and gas exchange variables were recorded continuously and blood lactate concentration [HLa] was assessed 3 min after the peak ramped test and at 2.5-min intervals during the time-trial. Peak values for power output (RMP(max)), heart rate (HR(peak)), oxygen uptake (VO2(peak)), and ventilation (V(Epeak)) attained during the ramped test were higher in the senior group (P < 0.05), whereas [HLa](peak), RER(peak), V(E): VO2(peak), and economy(peak) were similar between groups (P > 0.05). Time-trial values (mean for duration of race) for power output (W(TT)), heart rate (HR(TT)), VO2 (VO(2TT)), and V(E) (V(ETT)) were higher in the seniors (P < 0.05), but [HLa](TT), RER(TT), V(ETT): VO2(TT), and economy(TT) were similar between the groups (P > 0.05). Time-trial exercise intensity, expressed as %RMP(max), %HR(peak), % VO2(peak), and % V(Epeak), was similar (P > 0.05) for seniors and veterans (W(TT): 81%, s = 2 vs. 78%, s = 8; HR(TT): 96%, s = 4 vs. 94%, s = 4; VO2(TT): 92%, s = 4 vs. 95%, s = 10; V(ETT): 89%, s = 8 vs. 85%, s = 8, respectively). Overall, seniors attained higher absolute values for power output, heart rate, VO2, and V(E) but not blood lactate concentration, respiratory exchange ratio (RER), V(E): VO2, and economy. Veterans did not accommodate age-related declines in time trial performance by maintaining higher relative exercise intensity. 相似文献
7.
Abstract Six games players (GP) and six endurance‐trained runners (ET) completed a standardized multiple sprint test on a non‐motorized treadmill consisting often 6‐s all‐out sprints with 30‐s recovery periods. Running speed, power output and oxygen uptake were determined during the test and blood samples were taken for the determination of blood lactate and pH. Games players tended to produce a higher peak power output (GP vs ET: 839 ± 114 vs 777 ± 89 W, N.S.) and higher peak speed (GP vs ET: 7.03 ± 0.3 vs 6.71 ± 0.3 m s‐1, N.S.), but had a greater decrement in mean power output than endurance‐trained runners (GP vs ET: 29.3 ± 8.1% vs 14.2 ± 11.1%, P < 0.05). Blood lactate after the test was higher for the games players (GP vs ET: 15.2 ± 1.9 vs 12.4 ± 1.7 mM, P < 0.05), but the decrease in pH was similar for both groups (GP vs ET: 0.31 ± 0.08 vs 0.28 ± 0.08, N.S.). Strong correlations were found between peak blood lactate and peak speed (r = 0.90, P < 0.01) and between peak blood lactate and peak power fatigue (r = 0.92, P<0.01). The average increase in oxygen uptake above pre‐exercise levels during the sprint test was greater for endurance‐trained athletes than for the games players (ET vs GP: 35.0 ± 2.2 vs 29.6 ± 3.0 ml kg‐1 min‐1 , P < 0.05), corresponding to an average oxygen uptake per sprint (6‐s sprint and 24 s of subsequent recovery) of 67.5 ± 2.9% and 63.0 ± 4.5% VO 2 max respectively (N.S.). A modest relationship existed between the average increase in oxygen uptake above pre‐exercise values during the sprint test and mean speed fatigue (r = ‐0.68, P < 0.05). Thus, the greater decrement in performance for the games players may be related to higher glycolytic rates as reflected by higher lactate concentrations and to their lower oxygen uptake during the course of the 10 sprints. 相似文献
8.
The aims of this study were: (1) to identify the exercise intensity that corresponds to the maximal lactate steady state in adolescent endurance-trained runners; (2) to identify any differences between the sexes; and (3) to compare the maximal lactate steady state with commonly cited fixed blood lactate reference parameters. Sixteen boys and nine girls volunteered to participate in the study. They were first tested using a stepwise incremental treadmill protocol to establish the blood lactate profile and peak oxygen uptake (VO2). Running speeds corresponding to fixed whole blood lactate concentrations of 2.0, 2.5 and 4.0 mmol x l(-1) were calculated using linear interpolation. The maximal lactate steady state was determined from four separate 20-min constant-speed treadmill runs. The maximal lactate steady state was defined as the fastest running speed, to the nearest 0.5 km x h(-1), where the change in blood lactate concentration between 10 and 20 min was < 0.5 mmol x l(-1). Although the boys had to run faster than the girls to elicit the maximal lactate steady state (15.7 vs 14.3 km x h(-1), P < 0.01), once the data were expressed relative to percent peak VO2 (85 and 85%, respectively) and percent peak heart rate (92 and 94%, respectively), there were no differences between the sexes (P > 0.05). The running speed and percent peak VO2 at the maximal lactate steady state were not different to those corresponding to the fixed blood lactate concentrations of 2.0 and 2.5 mmol x l(-1) (P > 0.05), but were both lower than those at the 4.0 mmol x l(-1) concentration (P < 0.05). In conclusion, the maximal lactate steady state corresponded to a similar relative exercise intensity as that reported in adult athletes. The running speed, percent peak VO2 and percent peak heart rate at the maximal lactate steady state are approximated by the fixed blood lactate concentration of 2.5 mmol x l(-1) measured during an incremental treadmill test in boys and girls. 相似文献
9.
《European Journal of Sport Science》2013,13(6):462-468
Abstract The probability of winning games of tennis has been modelled in terms of the probability of the server winning an individual point. These models are based on the assumptions of stationarity of the point and interdependence. Stationarity is the assumption that the outcome of tennis points is not influenced by the game score at the beginning of the point. The purpose of the current investigation was to compare the outcomes of tennis points during break points and non-break points using data from 528 men's singles tennis matches from all four Grand Slam tournaments in 2008 and 2009. The retrospective probability of the receiver winning a point was 0.42 ± 0.23 during break points which was significantly greater than the 0.38 ± 0.10 during non-break points (P < 0.001). This, in turn, led to players creating significantly more break points than expected (P < 0.001) and breaking serve more frequently than expected (P < 0.001) for the points won when receiving serve. This is evidence that stationarity cannot be assumed and that models of winning tennis games may need to be enhanced to address improved receiver performance during break points. 相似文献
10.
Ermanno Rampinini Franco M. Impellizzeri Carlo Castagna Grant Abt Karim Chamari Aldo Sassi 《Journal of sports sciences》2013,31(6):659-666
Abstract The aim of this study was to examine the effects of exercise type, field dimensions, and coach encouragement on the intensity and reproducibility of small-sided games. Data were collected on 20 amateur soccer players (body mass 73.1 ± 8.6 kg, stature 1.79 ± 0.05 m, age 24.5 ± 4.1 years, [Vdot]O2max 56.3 ± 4.8 ml · kg?1 · min?1). Aerobic interval training was performed during three-, four-, five- and six-a-side games on three differently sized pitches, with and without coach encouragement. Heart rate, rating of perceived exertion (RPE) on the CR10-scale, and blood lactate concentration were measured. Main effects were found for exercise type, field dimensions, and coach encouragement (P < 0.05), but there were no interactions between any of the variables (P > 0.15). During a six-a-side game on a small pitch without coach encouragement, exercise intensity was 84 ± 5% of maximal heart rate, blood lactate concentration was 3.4 ± 1.0 mmol · l?1, and the RPE was 4.8. During a three-a-side game on a larger pitch with coach encouragement, exercise intensity was 91 ± 2% of maximal heart rate, blood lactate concentration was 6.5 ± 1.5 mmol · l?1, and the RPE was 7.2. Typical error expressed as a coefficient of variation ranged from 2.0 to 5.4% for percent maximal heart rate, from 10.4 to 43.7% for blood lactate concentration, and from 5.5 to 31.9% for RPE. The results demonstrate that exercise intensity during small-sided soccer games can be manipulated by varying the exercise type, the field dimensions, and whether there is any coach encouragement. By using different combinations of these factors, coaches can modulate exercise intensity within the high-intensity zone and control the aerobic training stimulus. 相似文献
11.
T. Platanou 《Journal of sports sciences》2013,31(11):1173-1181
Abstract In this study, we assessed exercise intensity in 20 water polo games of different duration. The hypothesis that right wing players perform at a higher intensity than back and forward central players was also tested. Thirty water polo players, equally split between three field positions, participated in the study. Initially, their performance-related physiological capabilities were evaluated. Subsequently, during water polo games of short (4×7-min periods) or long duration (4×9-min periods), heart rate was monitored continuously and blood lactate concentration was measured at the end of each period. Activity patterns were also recorded using a video camera. Mean heart rate over the entire game was 156 ± 18 beats · min?1. Overall exercise intensity fluctuated around a value corresponding to the lactate threshold (4.03 ± 0.96 mmol · l?1, 86 ± 5% of peak heart rate) and decreased (P < 0.003) with game time (4.22 ± 1.8 and 3.47 ± 1.9 mmol · l?1 in the second and fourth quarter, respectively). During the last 6 min, heart rate was higher (P < 0.001) in games of short duration (156 ± 3 beats · min?1) than in games of long duration (152 ± 8 beats · min?1). Video analysis showed that the percentage of time spent in low-intensity activities (i.e. “out of game”) was lower (23 vs. 26%), whereas that in high-intensity activities (i.e. “sprinting crawl”) was higher (21 vs. 19%), in games of short compared with long duration. No difference was observed among players of various field positions in any of the variables examined. Thus during match-play, games of long duration produced significantly lower heart rate responses than games of short duration, and the physiological response exhibited by the players was not affected by field position. The water polo authorities should consider these results before changing game duration and coaches should prepare their athletes accordingly. 相似文献
12.
The aims of this study were to examine and compare selected physiological and metabolic responses of wheelchair athletes in two paraplegic racing classes [T3: n?=?8 (lesion levels T1–T7; paraplegics); T4: n?=?9 (lesion levels below T7; paraplegics)] to prolonged exercise. In addition, we describe the responses of three tetraplegic athletes [T2: n?=?3 (lesion levels C6/C7: tetraplegics)]. Twenty athletes completed 90?min of exercise at 75% [Vdot]O2peak on a motorized treadmill adapted for wheelchairs. The mean (±s) heart rates of the T3 and T4 racing classes were 165±2 and 172±6 beats?·?min?1, respectively. For the T4 racing class, heart rate gradually increased during the test (P?<0.05), whereas for the T3 racing class, heart rate reached a plateau after an initial increase. The mean heart rate of the tetraplegics was 114±3 beats?·?min?1. The T3 and T4 classes exhibited similar respiratory exchange ratios, plasma lactate and glucose concentrations throughout the test. For both the T3 and T4 racing class, free fatty acid, glycerol, ammonia, urea and potassium concentrations had increased from resting values by the end of the test (P?<0.05). In conclusion, the results of this study suggest that endurance-trained wheelchair athletes are able to maintain velocities equivalent to the same relative exercise intensity (75% [Vdot]O2peak) for prolonged periods irrespective of lesion level. 相似文献
13.
Abstract To develop a track version of the maximal anaerobic running test, 10 sprint runners and 12 distance runners performed the test on a treadmill and on a track. The treadmill test consisted of incremental 20-s runs with a 100-s recovery between the runs. On the track, 20-s runs were replaced by 150-m runs. To determine the blood lactate versus running velocity curve, fingertip blood samples were taken for analysis of blood lactate concentration at rest and after each run. For both the treadmill and track protocols, maximal running velocity (v max), the velocities associated with blood lactate concentrations of 10 mmol · l?1 ( v 10 mM) and 5 mmol · l?1 ( v 5 mM), and the peak blood lactate concentration were determined. The results of both protocols were compared with the seasonal best 400-m runs for the sprint runners and seasonal best 1000-m time-trials for the distance runners. Maximal running velocity was significantly higher on the track (7.57 ± 0.79 m · s?1) than on the treadmill (7.13 ± 0.75 m · s?1), and sprint runners had significantly higher v max, v 10 mM, and peak blood lactate concentration than distance runners (P<0.05). The Pearson product – moment correlation coefficients between the variables for the track and treadmill protocols were 0.96 (v max), 0.82 (v 10 mM), 0.70 (v 5 mM), and 0.78 (peak blood lactate concentration) (P<0.05). In sprint runners, the velocity of the seasonal best 400-m run correlated positively with v max in the treadmill (r = 0.90, P<0.001) and track protocols (r = 0.92, P<0.001). In distance runners, a positive correlation was observed between the velocity of the 1000-m time-trial and v max in the treadmill (r = 0.70, P<0.01) and track protocols (r = 0.63, P<0.05). It is apparent that the results from the track protocol are related to, and in agreement with, the results of the treadmill protocol. In conclusion, the track version of the maximal anaerobic running test is a valid means of measuring different determinants of sprint running performance. 相似文献
14.
Joseph L. Andreacci Linda M. Lemura Steven L. Cohen Ethan A. Urbansky Sara A. Chelland Serge P. von Duvillard 《Journal of sports sciences》2013,31(4):345-352
The aim of this study was to determine the effects of frequency of verbal encouragement during maximal exercise testing. Twenty-eight participants (12 males, 16 females) aged 20.9 - 1.5 years (mean - s ) performed a maximal exercise test ( V O 2max ) on a treadmill without any verbal encouragement. The participants were matched according to their pre-test V O 2max and placed into either a control group or one of three experimental groups. They performed a second exercise test (post-test) 1 week later. During the second test, the control group received no verbal encouragement; the 20 s (20E), 60 s (60E) and 180 s (180E) encouragement groups received verbal encouragement every 20, 60 and 180 s, respectively, beginning with stage 3 of the exercise test. Relative V O 2max , exercise time, blood lactate concentration, respiratory exchange ratio (RER) and ratings of perceived exertion (RPE) were not significantly different from the first test to the second test for the control group without verbal encouragement and the 180E group that received infrequent encouragement. Post-test values were significantly higher than pre-test values for the 20E and 60E groups. The post-test values of the 20E group were significantly higher than their pre-test values for relative V O 2max ( P ? 0.001), exercise time ( P ? 0.0001), blood lactate concentr . ation ( P ? 0.05), RER ( P ? 0.01) and RPE ( P ? 0.0001); this was also the case for the 60E group for relative V O 2max ( P ? 0.01), blood lactate concentration ( P ? 0.05), RER ( P ? 0.05) and RPE ( P ? 0.05). The results suggest that frequent verbal encouragement (every 20 s and 60 s in the present study) leads to significantly greater maximum effort in a treadmill test than when no encouragement is given or when the encouragement is infrequent (i.e. every 180 s). 相似文献
15.
Jordan Santos-Concejero Ross Tucker Cristina Granados Jon Irazusta Iraia Bidaurrazaga-Letona Jon Zabala-Lili 《Journal of sports sciences》2013,31(9):853-859
AbstractThis study investigated the influence of the regression model and initial intensity during an incremental test on the relationship between the lactate threshold estimated by the maximal-deviation method and performance in elite-standard runners. Twenty-three well-trained runners completed a discontinuous incremental running test on a treadmill. Speed started at 9 km · h?1 and increased by 1.5 km · h?1 every 4 min until exhaustion, with a minute of recovery for blood collection. Lactate–speed data were fitted by exponential and polynomial models. The lactate threshold was determined for both models, using all the co-ordinates, excluding the first and excluding the first and second points. The exponential lactate threshold was greater than the polynomial equivalent in any co-ordinate condition (P < 0.001). For both models, the lactate threshold was lower when all co-ordinates were used than when the first and the first and second points were excluded (P < 0.001). 10-km race pace was correlated with both the exponential and polynomial lactate thresholds for all the co-ordinate conditions (r ≥ 0.75, P < 0.001 and r ≥ 0.56, P < 0.05, respectively). The results suggest that the exponential lactate threshold should be used instead of the polynomial equivalent since it is more strongly associated with performance and is independent of the initial intensity of the test. 相似文献
16.
Emma Ross Natalie Middleton Rob Shave Keith George Alison McConnell 《Journal of sports sciences》2013,31(12):1295-1301
Abstract Respiratory muscle fatigue has been reported following short bouts of high-intensity exercise, and prolonged, moderate-intensity exercise, as evidenced by decrements in inspiratory and expiratory mouth pressures. However, links to functionally relevant outcomes such as breathing effort have been lacking. The present study examined dyspnoea and leg fatigue during a treadmill marathon in nine experienced runners. Maximal inspiratory and expiratory pressure, peak inspiratory and expiratory flow, forced vital capacity, and forced expiratory volume in one second were assessed before, immediately after, and four and 24 hours after a marathon. During the run, leg effort was rated higher than respiratory effort from 18 through 42 km (P < 0.05). Immediately after the marathon, there were significant decreases in maximal inspiratory pressure and peak inspiratory flow (from 118 ± 20 cm H2O and 6.3 ± 1.4 litres · s?1 to 100 ± 22 cm H2O and 4.9 ± 1.5 litres · s?1 respectively; P < 0.01), while expiratory function remained unchanged. Leg maximum voluntary contraction force was significantly lower post-marathon. Breathing effort correlated significantly with leg fatigue (r = 0.69), but not inspiratory muscle fatigue. Our results confirm that prolonged moderate-intensity exercise induces inspiratory muscle fatigue. Furthermore, they suggest that the relative intensity of inspiratory muscle work during exercise makes some contribution to leg fatigue. 相似文献
17.
Steven E. Riechman Robert F. Zoeller G. Balasekaran Fredric L. Goss Robert J. Robertson 《Journal of sports sciences》2013,31(9):681-687
The aim of this study was to predict indoor rowing performance in 12 competitive female rowers (age 21.3 - 3.6 years, height 1.68 - 0.54 m, body mass 67.1 - 11.7 kg; mean - s ) using a 30 s rowing sprint, maximal oxygen uptake and the blood lactate response to submaximal rowing. Blood lactate and oxygen uptake ( V O 2 ) were measured during a discontinuous graded exercise test on a Concept II rowing ergometer incremented by 25 W for each 2 min stage; the highest V O 2 measured during the test was recorded as V O 2max (mean = 3.18 - 0.35 l· min -1 ). Peak power (380 - 63.2 W) and mean power (368 - 60.0 W) were determined using a modified Wingate test protocol on the Concept II rowing ergometer. Rowing performance was based on the results of the 2000 m indoor rowing championship in 1997 (466.8 - 12.3 s). Laboratory testing was performed within 3 weeks of the rowing championship. Submitting mean power (Power), the highest and lowest five consecutive sprint power outputs (Maximal and Minimal), percent fatigue in the sprint test (Fatigue), V O 2max (l· min -1 ), V O 2max (ml·kg -1 ·min -1 ), V O 2 at the lactate threshold, power at the lactate threshold (W), maximal lactate concentration, lactate threshold (percent V O 2max ) and V E max (l·min -1 ) to a stepwise multiple regression analysis produced the following model to predict 2000 m rowing performance: Time 2000 =- 0.163 (Power)14.213 ·( V O 2max l· min -1 ) + 0.738· (Fatigue) + 567.259 ( R 2 = 0.96, standard error = 2.89). These results indicate that, in the women studied, 75.7% of the variation in 2000 m indoor rowing performance time was predicted by peak power in a rowing Wingate test, while V O 2max and fatigue during the Wingate test explained an additional 12.1% and 8.2% of the variance, respectively. 相似文献
18.
Joanne L. Fallowfield Clyde Williams Jeanette Booth Boon H. Choo Sally Growns 《Journal of sports sciences》2013,31(6):497-502
This study examined the influence of water ingestion on endurance capacity during submaximal treadmill running. Four men and four women with a mean (± S.E.) age of 21.4 ± 0.7 years, height of 169 + 2 cm, body mass of 63.1 ± 2.9 kg and VO 2 max of 51.1 ± 1.8 ml kg?1 min?1, performed two randomly assigned treadmill runs at 70% VO 2 max to exhaustion. No fluid was ingested during one trial (NF‐trial), whereas a single water bolus of 3.0 ml kg?1 body mass was ingested immediately pre‐exercise and serial feedings of 2.0 ml kg?1 body mass were ingested every 15 min during exercise in a fluid replacement trial (FR‐trial). Run time for the NF‐trial was 77.7 ± 7.7 min, compared to 103 ± 12.4 min for the FR‐trial (P<0.01). Body mass (corrected for water ingestion) decreased by 2.0 ± 0.2% in the NF‐trial and 2.7 ± 0.2% in the FR‐trial (P<0.01), while plasma volume decreased by 1.1 ± 1.1% and 3.5 ± 1.1% in the two trials respectively (N.S.). However, these apparent differences in circulatory volume were not associated with differences in rectal temperature. Respiratory exchange ratios indicated increased carbohydrate metabolism (73% vs 64% of total energy expenditure) and suppressed fat metabolism after 75 min of exercise in the NF‐trial compared with the FR‐trial (NF‐trial, 0.90 ± 0.01; FR‐trial, 0.86 ± 0.03; P<0.01). Blood glucose concentrations were similar in both trials, while blood lactate concentrations were higher in the NF‐trial at the end of exercise (4.83 ± 0.34 vs 4.18 ± 0.38 mM; P<0.05). In summary, water ingestion during prolonged running improved endurance capacity. 相似文献
19.
This study compared the neuromuscular, metabolic and hormonal profiles of trained prepubescent tennis players and an untrained group. The boys in the experimental group (n = 9; mean age ± S.D. = 11.4 ± 0.5 years) had participated in tennis training for 2.3 ± 1.0 years and the boys in the control group (n = 9; mean age ± S.D. = 10.9 ± 0.4 years) were normal active volunteers. The tennis players were found to be physically more active than the controls when the comparison was made for either 1 year (4.9 ± 1.8 vs 2.6 ± 2.5 times per week; P<0.05) or for 1 week (3.4 + 1.2 vs 0.4 ± 0.5 times; P < 0.001) preceding the tests. Choice reaction time was significantly (P <0.01) shorter in the experimental group (258 ± 16 ms) than in the control group (344 + 81 ms). Dropping height in the best drop jump was significantly (P< 0.05) higher in the tennis players (0.46 + 0.19 m) than in the control boys (0.27 ± 0.10 m). The tennis players had significantly lower oxygen consumption at the ‘anaerobic threshold’ than the controls (P < 0.05). There were no significant differences between the groups in serum hormone levels. The small differences that existed may have been caused by actice participation in sport by the tennis players. 相似文献
20.
This study examined the effects of different work?–?rest durations during 40?min intermittent treadmill exercise and subsequent running performance. Eight males (mean?±?s: age 24.3?±?2.0 years, body mass 79.4?±?7.0?kg, height 1.77?±?0.05?m) undertook intermittent exercise involving repeated sprints at 120% of the speed at which maximal oxygen uptake (v-[Vdot]O2max) was attained with passive recovery between each one. The work?–?rest ratio was constant at 1:1.5 with trials involving short (6:9?s), medium (12:18?s) or long (24:36?s) work?–?rest durations. Each trial was followed by a performance run to volitional exhaustion at 150% v-[Vdot]O2max. After 40?min, mean exercise intensity was greater during the long (68.4?±?9.3%) than the short work?–?rest trial (54.9?±?8.1% [Vdot]O2max; P?<?0.05). Blood lactate concentration at 10?min was higher in the long and medium than in the short work?–?rest trial (6.1?±?0.8, 5.2?±?0.9, 4.5?±?1.3?mmol?·?l?1, respectively; P?<?0.05). The respiratory exchange ratio was consistently higher during the long than during the medium and short work?–?rest trials (P <?0.05). Plasma glucose concentration was higher in the long and medium than in the short work?–?rest trial after 40?min of exercise (5.6?±?0.1, 6.6?±?0.2 and 5.3?±?0.5?mmol?·?l?1, respectively; P?<?0.05). No differences were observed between trials for performance time (72.7?±?14.9, 63.2?±?13.2, 57.6?±?13.5?s for the short, medium and long work?–?rest trial, respectively; P = 0.17), although a relationship between performance time and 40?min plasma glucose was observed (P?<?0.05). The results show that 40?min of intermittent exercise involving long and medium work?–?rest durations elicits greater physiological strain and carbohydrate utilization than the same amount of intermittent exercise undertaken with a short work?–?rest duration. 相似文献