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1.
The purpose of this study was to examine the validity and reliability of the Cooper 12-min swim test in high school male swimmers ages 13 to 17. Thirty-three boys performed three 12-min swims and 1 maximal graded treadmill test within a 14-day period. One practice swim was conducted 1 week prior to participation in this study. VO2max was assessed by indirect calorimetry with open-circuit spirometry with the Truemax 2400 metabolic cart (Consentius Technologies, Sandy, UT). Test-retest reliability of the 12-min swim assessed via 1-way analysis of variance indicated moderate reliability (R = .66, 95% confidence interval [CI] = .42-.81), whereas concurrent validity assessed via a Pearson product-moment correlation indicated a moderate relation (r = .47, 95% CI = .15-.70, r2 = .22). Results indicate that the Cooper 12-min swimming test is only moderately reliable after 2 practice swims and does not appear to be a valid field test of aerobic capacity in high school male swimmers ages 13 to 17.  相似文献   

2.
Determinants of success during triathlon competition   总被引：1，自引：0，他引：1  
Eleven male triathletes were studied to determine the relationships between selected metabolic measurements and triathlon performance. Measurements of oxygen uptake (VO2), pulmonary ventilation (VE), and heart rate (HR) were made during submaximal and maximal 365.8 m freestyle swimming (FS), cycle ergometry (CE), and treadmill running (TR). Submaximal workloads were 1 m/s for swimming, 200 W for cycling, and 201.2 m/min for running. The mean VO2 max (l/min) was significantly (p less than .05) lower during FS (4.17) than CE (4.68) or TR (4.81). Swimming, cycling, and running performance times during the Muncie Endurathon (1.2 mile swim, 56 mile cycle, 13.1 mile run) were not significantly related to the event-specific VO2 max (ml/kg/min): -.49, -32 and -.55, respectively. The VO2 max expressed in l/min was found to be significantly (p less than .05) related to cycling time (r = -.70). A significant (p less than .05) relationship was observed between submaximal VO2 (ml/kg/min) during TM and run performance time (r = .64), whereas swimming and cycling performance times were significantly (p less than .05) related to submaximal VO2 max (l/min), r = .72 and .60, respectively. The percentage of VO2 (%VO2 max) used during the submaximal tests was significantly (p less than .05) related to swimming (.91), cycling (.78), and running (.86) performance times. Time spent running and cycling during triathlon competition was significantly (p less than .05) related to overall triathlon time, r = .97 and .81, respectively. However, swimming time was not significantly related (.30) to overall triathlon time. This study suggests that economy of effort is an important determinant of triathlon performance.  相似文献   

3.
Thirty-eight female subjects (M +/ SD = 33 +/- 3.0 years) had VO2max measured on the cycle ergometer (M +/- SD = 37.3 +/- 6.4 ml.kg-1.min-1) and on the treadmill (M +/- SD = 41.3 +/- 6.6 ml.kg-1.min-1). VO2max was estimated for each subject from heart rate (HR) at submaximal workloads on the cycle ergometer using the Astrand-Rhyming nomogram (A/R) and the extrapolation method (XTP). VO2max was also estimated from three field tests: 1.5-mile run (RUN) (independent variable [IV] = time), mile walk (WALK) (IV = time, age, HR, gender, body weight), and the Queens College Step Test (ST) (IV = HR during 5-20 s recovery). Repeated measure ANOVA revealed significant mean differences between the criterion cycle ergometer VO2max versus A/R and XTP (20 and 12% overestimation). The WALK, RUN, and ST VO2max values were not significantly different from the criterion treadmill VO2max. The correlation between criterion VO2max estimated from the WALK and RUN were r = .73 (SEE = 4.57 ml,kg-1.min-1) and r = .79 (SEE = 4.13 ml.kg-1.min-1), respectively. The ST, A/R, and XTP had higher SEEs (13-13.5% of the mean) and lower r s (r = .55 to r = .66). These results suggest both the WALK and RUN tests are satisfactory predictors of VO2max in 30 to 39-year-old females.  相似文献   

4.
Abstract

Few studies of young competitive swimmers have measured the swimmer in the water, but many have utilized the treadmill or bicycle ergometer on land. The maximum oxygen uptake of 31 (17 male and 14 female) competitive swimmers, 9 to 17 years of age, was determined during an intermittent tethered swimming test which consisted of a series of 3-minute workloads followed by 3-minute rest intervals. Each new workload was increased by multiples of 1.1 kg, and the work was continued to voluntary exhaustion. The subjects were members of a competitive swim club that took part in vigorous swim training throughout the year. Testing was conducted at the peak of the competitive out-door season. Over a period of a year, the daily training distance of these swimmers averaged approximately 7,000 yards, or almost four times that reported by others. The mean maximum oxygen uptake was 48.8 ml·kg?1·min?1 for the females and 55.8 ml·kg?1·min?1 for the males. Although the values for the younger swimmers were comparable with other published studies, the older male and female swimmers exhibited consistently higher values. The natural decline in maximum oxygen uptake per unit weight (ml/kg) reported by others in pubescent females was reversed by the over-distance training in the present study.  相似文献   

5.
Oxygen uptake (VO2) during treadmill exercise is directly related to the speed and grade, as well as the participant's body weight. To determine whether body composition also affects VO2 (ml.kg-1.min-1) during exercise, we studied 14 male body builders (M weight = 99 kg, SD = 7; M height = 180 cm, SD = 8; M body fat = 8%, SD = 3; M fat free mass = 91 kg, SD = 7) and 14 weight-matched men (M weight = 99 kg, SD = 9; M height = 179 cm, SD = 5; M body fat = 24%, SD = 5; M fat free mass = 73 kg, SD = 9). Percentage of body fat, t(13) = 8.185, p < .0001, and fat free mass, t(13) = 5.723, p < .0001, were significantly different between groups. VO2 was measured by respiratory gas analysis at rest and during three different submaximal workrates while walking on the treadmill without using the handrails for support. VO2 was significantly greater for the lean, highly muscular men at rest: 5.6 +/- 1 vs. 4.0 +/- 1 ml.kg-1.min-1, F(1, 26) = 21.185, p < .001; Stage 1: 1.7 mph/10%, 18.5 +/- 2 vs. 16.1 +/- 2 ml.kg-1.min-1, F(1, 26) = 6.002, p < .05; Stage 2: 2.5 mph/12%, 26.6 +/- 3 vs. 23.1 +/- 2 ml.kg-1.min-1, F(1, 26) = 7.991, p < .01; and Stage 3:3.4 mph/14%, 39.3 +/- 5 vs. 33.5 +/- 5 ml.kg-1.min-1, F(1, 26) = 7.682, p < .01, body builders versus weight-matched men, respectively. However, net VO2 (i.e., exercise VO2 - rest VO2) was not significantly different between the two groups at any of the matched exercise stages. The findings from this study indicate that VO2 during weight-bearing exercise performed at the same submaximal workrate is higher for male body builders compared to that measured in weight-matched men and that which is predicted by standard equations. These observed differences in exercise VO2 appear to be due to the higher resting VO2 in highly muscular participants.  相似文献   

6.
The purpose of this study was threefold: to determine (a) the test-retest reliability of the 20-m shuttle test (20 MST) (number of laps), (b) the concurrent validity of the 20 MST (number of laps), and (c) the validity of the prediction equation for VO2max developed by Léger, Mercier, Gadoury, and Lambert (1988) on Canadian children for use with American children 12-15 years old. An intraclass coefficient of .93 was obtained on 20 students (12 males; R = .91 and 8 females; R = .87) who completed the test twice, 1 week apart (MT1 = 47.80 +/- 20.29 vs. MT2 = 50.55 +/- 22.39 laps; p > or = .13). VO2peak was obtained by a treadmill test to volitional fatigue on 48 subjects. The number of laps run correlated significantly with VO2peak in males (n = 22; r = .65; F [1, 20] = 14.30 p < or = .001), females (n = 26; r = .51; F [1, 24] = 8.34; p < or = .01), and males and females = (r = .69; F [1, 46] = 42.54, p < or = .001). When the measured VO2peak (M = 49.97 +/- 7.59 ml.kg-1.min-1) was compared with the estimated VO2max (M = 48.72 +/- 5.72 ml.kg-1.min-1) predicted from age and maximal speed of the 20 MST (Léger et al., 1988) no significant difference was found, t (47) = -1.631; p > or = .11, between the means; the r was .72 and SEE was 5.26 ml.kg-1.min-1.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

7.
Traditionally, it has been assumed that during middle-distance running oxygen uptake (VO2) reaches its maximal value (VO2max) providing the event is of a sufficient duration; however, this assumption is largely based on observations in individuals with a relatively low VO2max. The aim of this study was to determine whether VO2max is related to the VO2 attained (i.e. VO2peak) during middle-distance running on a treadmill. Fifteen well-trained male runners (age 23.3 +/- 3.8 years, height 1.80 +/- 0.10 m, body mass 76.9 +/- 10.6 kg) volunteered to participate in the study. The participants undertook two 800-m trials to examine the reproducibility of the VO2 response. These two trials, together with a progressive test to determine VO2max, were completed in a randomized order. Oxygen uptake was determined throughout each test using 15-s Douglas bag collections. Following the application of a 30-s rolling average, the highest VO2 during the progressive test (i.e. VO2max) was compared with the highest VO2 during the 800-m trials (i.e. VO2peak) to examine the relationship between VO2max and the VO2 attained in the 800-m trials. For the 15 runners, VO2max was 58.9 +/- 7.1 ml x kg(-1) x min(-1). Two groups were formed using a median split based on VO2max. For the high and low VO2max groups, VO2max was 65.7 +/- 3.0 and 52.4 +/- 1.8 ml x kg(-1) x min(-1) respectively. The limits of agreement (95%) for test-retest reproducibility for the VO2 attained during the 800-m trials were +/- 3.5 ml x kg(-1) x min(-1) for a VO2peak of 50.6 ml x kg(-1) x min(-1) (the mean VO2peak for the low VO2max group) and +/- 2.3 ml x kg(-1) x min(-1) for a VO2peak of 59.0 ml x kg(-1) x min(-1) (the mean VO2peak for the high VO2max group), with a bias in VO2peak between the 800-m runs (i.e. the mean difference) of 1.2 ml x kg(-1) x min(-1). The VO2peak for the 800-m runs was 54.8 +/- 4.9 ml x kg(-1) x min(-1) for all 15 runners. For the high and low VO2max groups, VO2peak was 59.0 +/- 3.3 ml x kg(-1) x min(-1) (i.e. 90% VO2max) and 50.6 +/- 2.0 ml x kg(-1) x min(-1) (i.e. 97% VO2max) respectively. The negative relationship (-0.77) between VO2max and % VO2max attained for all 15 runners was significant (P = 0.001). These results demonstrate that (i) reproducibility is good and (ii) that VO2max is related to the %VO2max achieved, with participants with a higher VO2max achieving a lower %VO2max in an 800-m trial on a treadmill.  相似文献   

8.
Children's Activity Rating Scale (CARS): description and calibration   总被引：1，自引：0，他引：1  
A five-level Children's Activity Rating Scale (CARS) was designed to categorize the intensity of physical activities and discriminate between levels of energy expenditure in young children. The CARS was used by trained observers over a 12-month period to assess physical activities of 3-4 year-old children during field observations. Agreement among observers using the CARS was 84.1% for 389 paired observation periods. The energy expenditure for each level was assessed by measuring VO2s and heart rates of 5-6 year-old children (12 boys, 13 girls) while they performed eight activities representing the CARS levels. Mean VO2s for the eight activities in Levels 1-5 ranged from 7.1 to 37.5 ml.kg BW-1.min-1 (1 to 5.42 METS; 14.5% to 80.6% of VO2max). Mean heart rates ranged from 89 to 183 b.min-1 for activities in Levels 1-5. VO2s and heart rates at each level were significantly different from all other levels. These data demonstrate that the CARS encompasses a wide range of energy expenditures, discriminates between levels of energy expenditure, and can be used by trained observers to reliably evaluate physical activity and estimate energy expenditure of young children.  相似文献   

9.
The aim of this study was to determine the incidence of subject drop-out on a multi-stage shuttle run test and a modified incremental shuttle run test in which speed was increased by 0.014m.s-1 every 20-m shuttle to avoid the need for verbal speed cues. Analysis of the multi-stage shuttle run test with 208 elite female netball players and 381 elite male lacrosse players found that 13 (+/-3) players stopped after the first shuttle of each new level, in comparison with 5 (+/-2) players on any other shuttle. No obvious drop-out pattern was observed on the incremental shuttle run test with 273 male and 79 female undergraduate students. The mean difference between a test-retest condition (n= 20) for peak shuttle running speed (-0.03+/- 0.01m.s-1) and maximal heart rate (0.4+/- 0.1 beats.min-1) on the incremental test showed no bias (P > 0.05). The 95% absolute confidence limits of agreement were 0.11m.s-1 for peak shuttle running speed and +/-5 beats.min-1 for maximal heart rate. The relationship (n= 27) between peak shuttle running speed on the incremental shuttle run test (4.22+/- 0.14m.s-1) and VO2max (59.0+/- 1.7ml.kg-1.min-1) was r=0.91 (P< 0.01), with a standard error of prediction of 2.6ml.kg-1.min-1. These results suggest verbal cues during the multi-stage shuttle run test may influence subject drop-out. The incremental shuttle run test shows no obvious drop-out patten and provides a valid estimate of VO2max.  相似文献   

10.
The purpose of the present investigation was to examine the concurrent and construct validity of the three-mile (4.83 km) run as a field test of aerobic capacity. Subjects included 109 college-aged males whose three-mile run time (M = 1310.31 +/- 184.48 s) was measured. Fifty of the subjects were given a maximal treadmill stress test, and their peak oxygen consumption (VO2peak) (M = 54.23 +/- 7.08 ml.kg-1.min-1) was measured. The three-mile run was conducted on an outdoor 0.25 mile (0.425 km) track, and split times were recorded each 110 yds (100.32 m) for the first and last laps and total time was recorded for laps 2 through 11. The correlation coefficient between the run time and VO2peak was -.58, indicating only moderate concurrent validity for the run as a field test for aerobic capacity. A factor analysis conducted on the split time data revealed a three-factor structure of a stable pace phase, an initial sprint, and a final sprint with the stable pace factor accounting for most of the common factor variance (69%). The three-mile run time was used to discriminate successfully between two known groups of subjects in aerobic capacity. These data provide a degree of support for the construct validity of the three-mile run as a field test of aerobic capacity.  相似文献   

11.
The aim of the present study was to determine the repeatability of a running endurance test using an automated treadmill system that requires no manual input to control running speed. On three separate occasions, 7 days apart, 10 experienced male endurance-trained runners (mean age 32 years, s = 10; VO2peak 61 ml x kg(-1) x min(-1), s = 7) completed a treadmill time trial, in which they were instructed to run as far as possible in 60 min. The treadmill was instrumented with an ultrasonic feedback-controlled radar modulator that spontaneously regulated treadmill belt speed corresponding to the changing running speed of each runner. Estimated running intensity was 70% VO2peak (s = 11) and the distance covered 13.5 km (s = 2), with no difference in mean performances between trials. The coefficient of variation, estimated using analysis of variance, with participant and trial as main effects, was 1.4%. In summary, the use of an automated treadmill system improved the repeatability of a 60-min treadmill time trial compared with time trials in which speed is controlled manually. The present protocol is a reliable method of assessing endurance performance in endurance-trained runners.  相似文献   

12.
This study investigated the construct and concurrent validity of a 12-minute crawl stroke swim as a field test of swimming endurance. A sample of 42 male college students who ranged from certified life savers to competitive swimmers were administered three tests. The first, a multistage swimming endurance test, required that a tethered subject swim to exhaustion under a linear progressive increase in workload. The second measure was the crawl stroke count for two lengths of a 25-yard pool. The third test was a 12-minute crawl stroke swim for distance with total distance and distance covered each minute recorded for each subject. Alpha factor analysis of the 12 minute intervals of the crawl stroke swim produced one factor which demonstrated that swimming performance was internally consistent during the 12-minute swim. There was a correlation of .898 (p < .01) between the 12-minute swim and the tethered swim test. Cross validity procedures demonstrated a high degree of stability for the correlation between the 12-minute swim and the tethered swim and for resulting regression statistics. The construct validity was established for both the multistage test and the 12-minute swim using the known groups approach. On the basis of the data the 12-minute swim is a valid field test for swimming endurance for the population studied.  相似文献   

13.
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 (VO2) 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 VO2 measured during the test was recorded as VO2max (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), VO2max (l.min-1), VO2max (ml.kg-1.min-1), VO2 at the lactate threshold, power at the lactate threshold (W), maximal lactate concentration, lactate threshold (percent VO2max) and VEmax (l.min-1) to a stepwise multiple regression analysis produced the following model to predict 2000 m rowing performance: Time2000 = -0.163 (Power) -14.213.(VO2max l.min-1) +0.738.(Fatigue) 7.259 (R2 = 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 VO2max and fatigue during the Wingate test explained an additional 12.1% and 8.2% of the variance, respectively.  相似文献   

14.
The physiological responses to skating and the incidence of injuries were recorded in young, Danish elite figure skaters (n = 8) over a 1-year period. The skaters' maximum oxygen uptake (VO2 max) ranged from 54.7 to 68.8 ml kg-1 min-1, and work intensity during simulated competitive figure skating corresponded to 89% VO2 max. Before the onset of competitive skating, but after a warm-up, blood lactate (BLa) concentration was measured as 2.0 +/- 0.05 mM (means +/- S.E.). After a 4-min run, BLa increased to 8.0 +/- 0.6 mM. The subjects' resting heart rates were measured each morning over a 1-year period and corresponded to 53 +/- 2 and 58 +/- 3 beats min-1 for the males and females respectively, with no systematic season-related variations. The skaters trained for 15-41 h per week, 60-95 min of this time being spent on warm-up activities. The injury incidence rate during competitive skating was recorded as 1.4 injuries per 1000 h of training, 56% of these being acute and 44% chronic injuries. Of those injuries registered, 83% were recalled by the skaters when a retrospective questionnaire was given to them at the end of the observation period. This study indicates that ice figure skating is associated with high aerobic power. Furthermore, Danish skaters spend large amounts of time on training, including warm-up and stretching. Despite the amount of training and the intensity of ice-skating programmes, injury rates are low compared with other sporting events.  相似文献   

15.
We examined the supposition that swimmers may exhibit an imbalance in bilateral arm power output during simulated swimming exercise. Ten competitive front crawl swimmers (5 males, 5 females; age 20.5+/-2.3 years; height 1.74+/-0.09 m; body mass 72.0+/-16.7 kg; 400 m freestyle swim time 278+/-20.5 s; mean +/- s) performed four incremental (10 W x min(-1)) swim ramp tests on a computer-interfaced biokinetic swim bench ergometer. External power output from each arm was measured continuously to exhaustion. The results showed that, throughout the course of the simulated swim, external power output clearly favoured the left arm (F1,9 = 12.5, P= 0.006). This was especially evident in the final 30 s to exhaustion, when 54.0+/-3.87% of external power output was derived from the left arm versus 46.0+/-3.87% from the right arm. The disparity in external power output was further highlighted when the participants were grouped into unilateral and bilateral breathers. Unilateral breathers (n = 5) produced 57.1+/-2.62% of external power output from the left armversus 42.9+/-2.62% from the right arm (P= 0.001). Bilateral breathers (n = 5) exhibited a more balanced external power output of 51.0+/-1.82% from the left arm and 49.0+/-1.82% from the right arm (P = 0.177). Evidence of power imbalance in the simulated swimming stroke may have important implications for optimizing swim performance. The observed power imbalance may be reduced when a bilateral breathing technique is adopted.  相似文献   

16.
The aim of this study was to determine the incidence of subject drop-out on a multi-stage shuttle run test and a modified incremental shuttle run test in which speed was increased by 0.014 m x s(-1) every 20-m shuttle to avoid the need for verbal speed cues. Analysis of the multi-stage shuttle run test with 208 elite female netball players and 381 elite male lacrosse players found that 13 (+/-3) players stopped after the first shuttle of each new level, in comparison with 5 (+/-2) players on any other shuttle. No obvious drop-out pattern was observed on the incremental shuttle run test with 273 male and 79 female undergraduate students. The mean difference between a test-retest condition (n = 20) for peak shuttle running speed (-0.03+/-0.01 m x s(-1)) and maximal heart rate (0.4+/-0.1 beats x min(-1)) on the incremental test showed no bias (P > 0.05). The 95% absolute confidence limits of agreement were+/-0.11 m x s(-1) for peak shuttle running speed and+/-5 beats min(-1) for maximal heart rate. The relationship (n = 27) between peak shuttle running speed on the incremental shuttle run test (4.22+/-0.14 m x s(-1)) and VO2max (59.0+/-1.7 ml kg(-1) x min(-1)) was r= 0.91 (P< 0.01), with a standard error of prediction of +/-2.6 ml x kg(-1) x min(-1). These results suggest verbal cues during the multi-stage shuttle run test may influence subject drop-out. The incremental shuttle run test shows no obvious drop-out patten and provides a valid estimate of VO2max.  相似文献   

17.
The purpose of the present study was to re-examine the relationship between deep body temperature and relative exercise intensity, during running rather than cycling (Saltin and Hermansen, 1966). Twenty male competitive and recreational distance runners, aged 22 + 0.9 years (mean +/- sx), were selected to form two groups, one with high maximal oxygen uptake (VO2max) values (72.8 +/- 0.8 ml x kg(-1) x min(-1)) and the other with moderate values (59.4 +/- 0.7 ml x kg(-1) x min(-1)). The participants completed two 60 min constant-paced treadmill runs at a common speed (absolute intensity) of 10.5 km x h(-1) and at a relative exercise intensity at a speed equivalent to 65% of VO2max. During the relative exercise intensity trial, no differences were found in rectal temperature, skin temperature or heart rate between groups. However, when running at the common speed, differences were identified in rectal temperature. At 60 min, rectal temperature was 37.70 +/- 0.19 degrees C and 38.19 +/- 0.11 degrees C for the high and moderate VO2max groups, respectively (P < 0.05). Sweat lost was significantly higher in the moderate VO2max group (moderate: 1.05 +/- 0.06 kg x h(-1); high: 0.82 +/- 0.08 kg x h(-1); P < 0.05). Heart rates were also different between groups over the first 20 min during the common speed trial (P < 0.05). The results of the present study support the findings of Saltin and Hermansen (1966), in that the set-point at which temperature is maintained is related to the relative exercise intensity.  相似文献   

18.
The aim of this study was to examine the variability of the oxygen uptake (VO2) kinetic response during moderate- and high-intensity treadmill exercise within the same day (at 06:00, 12:00 and 18:00 h) and across days (on five occasions). Nine participants (age 25 +/- 8 years, mass 70.2 +/- 4.7 kg, VO2max 4137 +/- 697 ml x min(-1); mean +/- s) took part in the study. Six of the participants performed replicate 'square-wave' rest-to-exercise transitions of 6 min duration at running speeds calculated to require 80% VO2 at the ventilatory threshold (moderate-intensity exercise) and 50% of the difference between VO2 at the ventilatory threshold and VO2max (50% delta; high-intensity exercise) on 5 different days. Although the amplitudes of the VO2 response were relatively constant (coefficient of variation approximately 6%) from day to day, the time-based parameters were more variable (coefficient of variation approximately 15 to 30%). All nine participants performed replicate square-waves for each time of day. There was no diurnal effect on the time-based parameters of VO2 kinetics during either moderate- or high-intensity exercise. However, for high-intensity exercise, the amplitude of the primary component was significantly lower during the 12:00 h trial (2859 +/- 142 ml x min(-1) vs 2955 +/- 135 ml x min(-1) at 06:00 h and 2937 +/- 137 ml x min(-1) at 18:00 h; P < 0.05), but this effect was eliminated when expressed relative to body mass. The results of this study indicate that the amplitudes of the VO2 kinetic responses to moderate- and high-intensity treadmill exercise are similar within and across test days. The time-based parameters, however, are more variable from day to day and multiple transitions are, therefore, recommended to increase confidence in the data.  相似文献   

19.
The single-stage treadmill walking test of Ebbeling et al. is commonly used to predict maximal oxygen consumption (.VO(2max)) from a submaximal effort between 50% and 70% of the participant's age-predicted maximum heart rate. The purpose of this study was to determine if this submaximal test correctly predicts .VO(2max) at the low (50% of maximum heart rate) and high (70% of maximum heart rate) ends of the specified heart rate range for males and females aged 18 - 55 years. Each of the 34 participants completed one low-intensity and one high-intensity trial. The two trials resulted in significantly different estimates of .VO(2max) (low-intensity trial: mean 40.5 ml . kg(-1) . min(-1), s = 9.3; high-intensity trial: 47.5 ml . kg(-1) . min(-1), s = 8.8; P < 0.01). A subset of 22 participants concluded their second trial with a .VO(2max) test (mean 47.9 ml . kg(-1) . min(-1), s = 8.9). The low-intensity trial underestimated (mean difference = -3.5 ml . kg(-1) . min(-1); 95% CI = -6.4 to -0.6 ml . kg(-1) . min(-1); P = 0.02) and the high-intensity trial overestimated (mean difference = 3.5 ml . kg(-1) . min(-1); 95% CI = 1.1 to 6.0 ml . kg(-1) . min(-1); P = 0.01) the measured .VO(2max). The predictive validity of Ebbeling and colleagues' single-stage submaximal treadmill walking test is diminished when performed at the extremes of the specified heart rate range.  相似文献   

20.
Longitudinal changes in submaximal oxygen uptake in 11- to 13-year-olds   总被引：3，自引：0，他引：3  
The aim of this study was to monitor longitudinal changes in young people's submaximal oxygen uptake (VO2) responses during horizontal treadmill running at 8 km x h(-1). The 236 participants (118 boys, 118 girls) were aged 11.2+/-0.4 years (mean +/- s) at the onset of the study. Submaximal VO2, peak VO2 and anthropometry were recorded annually for three consecutive years. The data were analysed using multi-level regression modelling within a multiplicative, allometric framework. The initial model examined sex, age and maturity-related changes in submaximal VO2 relative to body mass as the sole anthropometric covariate. Our results demonstrate that the conventional ratio standard ml x kg(-1) x min(-1) does not adequately describe the true relationship between body mass and submaximal VO2 during this period of growth. The effects of maturity and age were non-significant, but girls consumed significantly less VO2 than boys running at 8 km x h(-1). In subsequent models, stature was shown to be a significant explanatory variable, but this effect became non-significant when the sum of two skinfolds was added. Thus, within this population, submaximal VO2 responses were explained predominantly by changes in body mass and skinfold thicknesses, with no additional maturity-related increments. When differences in body mass and skinfolds were controlled for, there was still a difference between the sexes in submaximal VO2, with girls becoming increasingly more economical with age.  相似文献   

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