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1.
Abstract

Oxygen uptake (VO2) and heart rate (HR) kinetics for submaximum exercise were compared in prepubescent boys (mean age ± SD = 10.2 ± 1.28 years, N = 21) and adult men (30.0 ± 5.64 years, N = 21). Standard open circuit spirometric techniques were used to determine VO2 and a bipolar ECG was used to measure HR. The kinetics of VO2 and HR were determined for each subject using graphic procedures. Subjects performed submaximum exercise on the bicycle ergometer at an intensity of 42 ± 1.3% (mean ± SE) of VO2 max for the children and 39 ± 0.7% of VO2 max for the adults (p = .07). There were no group differences in VO2 t1/2 (children t1/2 = 18.5 ± 0.75 secs and adults t1/2 = 17.4 ± 0.39 secs, p = .18) and HR t1/2 (children t1/2 = 11.4 ± 1.86 secs and adults t1/2 = 13.6 ± 1.66 secs, p = .38). These data suggest that children and adults do not differ in cardiorespiratory adjustments during low intensity exercise. This is in contrast to suggestions of other investigators that children have a faster cardiovascular adjustment to exercise.  相似文献   

2.
Abstract

This study was designed to examine the magnitude and duration of excess postexercise oxygen consumption (EPOC) following upper body exercise, using lower body exercise for comparison. On separate days and in a counterbalanced order, eight subjects (four male and four female) performed a 20-min exercise at 60% of mode-specific peak oxygen uptake (VO2) using an arm crank and cycle ergometer. Prior to each exercise, baseline VO2 and heart rate (HR) were measured during the final 15 min of a 45-min seated rest. VO2 and HR were measured continuously during the postexercise period until baseline VO2 was reestablished. No significant difference between the two experimental conditions was found for magnitude of EPOC (t [7] = 0.69, p > .05). Mean (± SD) values were 9.2 ± 3.3 and 10.4 ± 5.8 kcal for the arm crank and cycle ergometer exercises, respectively. Duration of EPOC was relatively short and not significantly different (t [7] = 0.24, p > .05) between the upper body (22.9 ± 13.7 min) and lower body (24.2 ± 19.4 min) exercises. Within the framework of the chosen exercise conditions, these results suggest EPOC may be related primarily to the relative metabolic rate of the active musculature, as opposed to the absolute exercise VO2 or quantity of active muscle mass associated with these two types of exercise.  相似文献   

3.
The purpose of this study was to verify within- and between-day repeatability and variability in children's oxygen uptake (VO2), gross economy (GE; VO2 divided by speed) and heart rate (HR) during treadmill walking based on self-selected speed (SS). Fourteen children (10.1 ± 1.4 years) undertook three testing sessions over 2 days in which four walking speeds, including SS were tested. Within- and between-day repeatability were assessed using the Bland and Altman method, and coefficients of variability (CV) were determined for each child across exercise bouts and averaged to obtain a mean group CV value for VO2, GE, and HR per speed. Repeated measures analysis of variance showed no statistically significant differences in within- or between-day CV for VO2, GE, or HR at any speed. Repeatability within- and between-day for VO2, GE, and HR for all speeds was verified. These results suggest that submaximal VO2 during treadmill walking is stable and reproducible at a range of speeds based on children's SS.  相似文献   

4.
Abstract

The transient oxygen uptake (VO2) response during the initial phase of exercise was investigated in 28 children (mean age ± SD = 10.2 ± 2.28 years) during constant load submaximum bicycle ergometer exercise (mean power output ± SD = 56 ± 4.0 watts; mean VO2 ± SD = .92 ± .141 [mdot] min-1). The VO2 half-time (VO2 - t½) averaged (± SD) 34.8 (± 12.70) sec which is similar to that observed in adults. Examination of the VO2-t ½ response as it related to age (7 to 14 years) showed that younger children attained steady-rate VO2 more quickly than older children (r = .77 between age and VO2-t½, P < .05). Body size, maturational level, exercise intensity, cardiorespiratory factors, and anaerobic potential are suggested as possible factors accounting for the positive age vs VO2-t ½ relationship.  相似文献   

5.
目的：通过分析上海地区不同项群优秀青少年有氧能力,寻找不同项群有氧能力特点。方法：选择上海市2003—2014年一线、二线运动员测试数据库,从中筛选88名16岁以上男性,年龄为（17.5±1.2）岁,103名15岁以上女性,年龄为（16.4±1.1）岁,均为国家二级以上运动员,对其最大摄氧量绝对值和相对值进行统计分析,使用单因素方差分析以及Z分值等方法比较不同性别各项群间有氧运动能力特点。结果：耐力项群最大摄氧量绝对值显著高于隔网对抗（P＜0.05）与格斗对抗（P＜0.01）。男性各项群间最大摄氧量相对值无显著差异;女性耐力项群最大摄氧量相对值显著高于同场对抗（P＜0.01）、隔网对抗（P＜0.01）与格斗对抗（P＜0.01）;女性同场对抗项群最大摄氧量相对值显著高于格斗对抗（P＜0.05）。结论：耐力项群最大摄氧量绝对值高于其他项群;体能主导类项群最大摄氧量相对值高于技能主导类项群;同场对抗项群最大摄氧量绝对值优于相对值,其余项群最大摄氧量相对值和绝对值同步。为科学训练提供有力数据支持,教练员可以结合项群有氧运动能力特点,判断运动员的有氧工作能力水平,从而针对性地制定训练计划,提高整体竞技水平。  相似文献   

6.
Purpose: The purpose of this investigation was to examine the effects of a submaximal running warm-up on running performance in male endurance athletes (n = 16, Mage = 21 ± 2 years, MVO2max = 69.3 ± 5.1 mL/kg/min). Method: Endurance performance was determined by a 30-min distance trial after control and submaximal running warm-up conditions in a randomized crossover fashion. The warm-up began with 5 min of quiet sitting, followed by 6 min of submaximal running split into 2-min intervals at speeds corresponding to 45%, 55%, and 65% maximal oxygen consumption (VO2max). A 2-min walk at 3.2 km/hr concluded the 13-min warm-up protocol. For the control condition, participants sat quietly for 13 min. VO2 and heart rate (HR) were determined at Minutes 0, 5, and 13 of the pre-exercise protocol in each condition. Results: At the end of 13 min prior to the distance trial, mean VO2 (warm-up = 14.1 ± 2.2 mL/kg/min vs. control = 5.5 ± 1.7 mL/kg/min) and mean HR (warm-up = 105 ± 11 bpm vs. control = 67 ± 11 bpm) were statistically greater (p < .001) in the warm-up condition compared with the control condition. The distance run did not statistically differ (p = .37) between the warm-up (7.8 ± 0.5 km) and control (7.7 ± 0.6 km) conditions; however, effect size calculation revealed a small effect (d = 0.2) in favor of the warm-up condition. Thus, the warm-up employed may have important and practical implications to determine placing among high-level athletes in close races. Conclusions: These findings suggest a submaximal running warm-up may have a small but critical effect on a 30-min distance trial in competitive endurance athletes. Further, the warm-up elicited increases in physiological variables VO2 and HR prior to performance; thus, a submaximal specific warm-up should warrant consideration.  相似文献   

7.
To adhere to the principle of “exercise specificity” exercise testing should be completed using the same physical activity that is performed during exercise training. The present study was designed to assess whether aerobic step exercisers have a greater maximal oxygen consumption (max VO2) when tested using an activity specific, maximal step exercise test (SET; arms and legs) versus a maximal running test (legs only). Female aerobic step exercisers (N=18; 20.7 ± 1.5 years) performed three maximal graded exercise tests (GXTs): 2 SETs; 1 treadmill test (TMT). The SET consisted of six 3-min progressive stages of alternate lead, basic step, basic step with biceps curls, knee raise with pull-down, repeater knee with pull-down, lateral lunge with pull-down, and side squat with shoulder presses. Stepping rate was 32 steps· min?1 on an 8-in (20.32 cm) step for stages 1–3, and a 10-in (25.4 cm) step for stages 4–6. Submaximal and maximal heart rate (HR) and oxygen consumption (VO2) were recorded at the end of each stage. Test–retest reliability for the first five stages of the SET ranged from .91 to .97 for HR, and from .84 to .96 for VO2. Maximal HR was significantly greater (p =.0001) for the SET (200 ± 6.2 beats·min?1) as compared to the TMT (193 ± 7.9 beats·min?1). No significant difference was found for max VO2 (42.9 ± 8.5, 41.2 ± 5.9 ml·kg?1·min?1, p =.14). The SET was a valid and reliable protocol for assessing responses of these aerobic step exercisers; however, max VO2 from a TMT did not differ significantly from the SET. Conversely, max HR obtained from the criterion TMT was 7 beats·min?1 lower than from the SET. If a training HR for step exercise (arms and legs exercise) is prescribed based on the max HR from treadmill exercise (legs only), then the training HR should be calculated from a TMT max HR that has been increased by 7 beats·min?1 to obtain an intensity of step exercise comparable to that of running.  相似文献   

8.
Abstract

Muscular and aerobic capacity changes resulting from three months of wrestling training were examined in a group of normally active 7- to 9-year-old boys (N = 23) who competed in an intramural league tournament. A nontraining group of twenty-two boys of similar age, height, and weight served as control subjects, and were studied during the same period of time. The subjects were measured for body dimensions and skinfolds, and were given measures of back lift, leg press, and arm endurance (dips and chins). They were also measured for [Vdot]E max, [Vdot]O 2 max, and HR max employing a progressive treadmill protocol. Results of ANCOVA analyses indicated that (1) the mean improvements in [Vdot]E max (2.93 1·min ?1 ) and in [Vdot]O 2 max (+ 6.6 ml·kg ?1 ·min ?1 ) were not significantly greater than control (p > .05), nor was HR max; (2) arm endurance improved significantly over control (p < .05), as did the leg press, but the back lift was not improved significantly (p > .05); (3) no significant change occurred in height, weight, or in some of skinfolds (p > .05), but the wrestlers were less endomorphic and more ectomorphic than their control counterparts, and were judged essentially equivalent in mesomorphy. It is concluded that wrestling training in young boys improves strength, but does not improve aerobic capacity more than one would expect to see in normal children of similar age and size.  相似文献   

9.
The first purpose of this study was to determine the norm-referenced predictive validity of maximal oxygen consumption (VO2) max estimated from the progressive aerobic cardiovascular endurance run (PACER, FITNESSGRAM®; Cooper Institute for Aerobic Research, Dallas, TX) performance by 3 separate formulas: the Leger, Mercier, Gadoury, and Lambert (1988) 8- to 19-year-old equation; the Leger et al. adult equation; and the Ramsbottom, Brewer, and Williams (1988) equation. Norm-referenced intraclass stability reliability coefficients (n = 19) were determined to be .96 for PACER and estimated VO2 max values. Only the VO2 max values estimated from the Leger et al. adult equation (47.29 ± 7.02 vs. 50.45 ± 8.01 rnL · kg-1 · min-1 measured; p < .0001) were shown to be valid (r = .82; standard error of estimate [SEE] = 4.59; Error = 5.58; percentage of participants whose measured VO2 max fell within ± 4.5 mL · kg-1 · min-1 of estimated VO2 max = 59.7; N = 60 female participants ± 59 male participants). The second purpose was to cross-validate the Cureton, Sloninger, O'Bannon, Black, and McCormack (1995) equation for the estimation of VO2 max from the one-mile run (1-MR). The results (estimated VO2 max = 48.06 ± 6.57 vs. 50.45 ± 8.01 rnL · kg-1 · min-1 measured; p < .0001; r= .82; SEE = 4.53; Error = 5.27; percentage = 61.7; N = 50 female ± 44 male participants) indicated a norm-referencedpredictive validity similar to the Leger et al. adult PACER equation. There was no significant difference between the VO2max estimated by the Leger et al. 8- to 19-year-old and the Cureton et al. equations. Correlations between 1-MR time and measured VO2 max (r = .78) and PACER laps and measured 90, maw (r = 33) supported norm-referenced concurrent validity in this population. The third purpose was to determine the criterion-referenced reliability and validity of the PACER and 1-MR. Criterion-referenced reliability indicated a proportion of agreement (P) of .95 and a modified Kappa (K) of .90 for PACER laps and estimated VO2 max. A .88 proportion of correct classification decisions (c) with a phi coefficient (?) of .08 was determined for criterion-referenced validity of the Leger et al. adult equation. Comparable validity coefficients for the Cureton et al. equation were c = .97 and ? = .65. Criterion-referenced equivalence reliability (P) was .90 with a Kq of .80 for the 1-MR and PACER. It was concluded that (a) the Leger et al. (1988) adult equation is the preferred equation to use to estimate VO2 max from PACER scores for college aged individuals; (b) the Cureton et al. (1995) equation is valid for estimating VO2 max in college students from the 1-MR; and (c) the FITNESSGRAM® (Cooper Institute for Aerobics Research, 1992) criterion-referenced standards using data from the Cureton et al. and Leger et al. adult equations were both reliable and valid in this population. The 1-MR and the PACER may be used interchangeably in this age group to assess cardiovascular fitness either from performance scores or estimated VO2 max if the Leger et al. adult equation is used for PACER VO2 max prediction.  相似文献   

10.
Abstract

The purpose of the present study was to determine the effects of 10-in [025–m] versus 16-in [0.41-m] wheelchair handrims on cardiorespiratory and psychophysiological exercise responses during wheelchair propulsion at selected velocities. Fifteen male paraplegics (27.0 ± 5.5 yrs) performed three discontinuous exercise tests (ACE = arm crank ergometer; WERG = wheelchair roller ergometer) and two 1600-m performance-based track trials (TRACK) under simulated race conditions. There were no significant differences in HR, VO2, VE, HLa, or category-ratio ratings of perceived exertion (RPE) using different handrims during wheelchair propulsion at 4 km-h1. In contrast, at 8 km-h?1 subjects demonstrated a 13% lower steady state VO2 (p < .05) using the 10-in handrims, coincident with a 23% lower VE Steady state HR during WERG at 8 km-h?1 using the 10-in (124.4 ± 39 b.min?1) or 16-in (130.6 ± 4.6 b.min?1) handrims were not significantly different. There were also no significant differences between ACE or WERG conditions during maximal effort for VO2 or VE. However, HRpeak during ACE was 7% higher than HRpeak during WERG16 (183 ± 15 b.min?1 vs. 171 ± 12 b.min?1, p < .05), and whole blood HLa during ACE was also significantly higher (by 2.3-2.5 mmol; p < .05) compared to WERG. There were no significant differences for HR, performance time, or RPE between trials using different handrim diameters during the 1600-m event. In contrast, HLa was significantly lower using smaller handrims (9.9 mmol) compared with larger handrims (11.3 mmol), paralleling a similar difference in the laboratory. Although these data demonstrated few significant differences of physiologic responses between trials using different handrims, there was a tendency for a lower metabolic stress using the smaller handrims.  相似文献   

11.
The minimum exercise intensity that elicits ?O2max (i?O2max) is an important variable associated with endurance exercise performance. i?O2max is usually determined during a maximal incremental exercise test; however, the magnitude and duration of the increments used influence the i?O2max value produced by a given test. The aims of this study were twofold. The first was to investigate whether the i?O2max value produced by a single cycle ergometer test (i?O2max(S)) was repeatable. The second was to determine if i?O2max(S) represents the minimum intensity at which ?O2max is elicited when compared to a refined i?O2max value (i?O2max(R)) derived from repeated tests. Seventeen male cyclists (age 33.9?±?7.7 years, body mass 80.9?±?10.2?kg, height 1.82?±?0.05?m; VO2max 4.27?±?0.62 L?min?1) performed four maximal incremental tests for the determination of i?O2max(S) and i?O2max(R) (3 min stages; 20?W increments). Trials 1 and 2 were identical and used for assessing the repeatability of i?O2max(S), trials 3 and 4 began at different intensities and were used to determine i?O2max(R). i?O2max(S) showed good test–retest repeatability for i?O2max (CV?=?4.1%; ICC?=?0.93), VO2max (CV?=?6.3%; ICC?=?0.88) and test duration (CV?=?6.7%; ICC?=?0.89). There was no significant difference between i?O2max(S) and i?O2max(R) (303?±?40?W vs. 301?±?42?W) (P?2max determined directly during a maximal incremental test is repeatable and provides a very good estimate of the minimum exercise intensity that elicits ?O2max.  相似文献   

12.
This study was designed to develop a single-stage submaximal treadmill jogging (TMJ) test to predict VO2max in fit adults. Participants (N?=?400; men?=?250 and women?=?150), ages 18 to 40 years, successfully completed a maximal graded exercise test (GXT) at 1 of 3 laboratories to determine VO2max. The TMJ test was completed during the first 2 stages of the GXT. Following 3 min of walking (Stage 1), participants achieved a steady-state heart rate (HR) while exercising at a comfortable self-selected submaximal jogging speed at level grade (Stage 2). Gender, age, body mass, steady-state HR, and jogging speed (mph) were included as independent variables in the following multiple linear regression model to predict VO2max (R?=?0.91, standard error of estimate [SEE]?=?2.52 mL?·?kg?1?·?min?1): VO2max (mL?·?kg?1?·?min?1)?=?58.687?+?(7.520 × Gender; 0?=?woman and 1?=?man)?+?(4.334 × mph) ? (0.211 × kg) ? (0.148 × HR) ? (0.107 × Age). Based on the predicted residual sum of squares (PRESS) statistics (RPRESS?=?0.91, SEE PRESS?=?2.54 mL?·?kg?1?·?min?1) and small total error (TE; 2.50 mL?·?kg?1?·?min?1; 5.3% of VO2max) and constant error (CE; ?0.008 mL?·?kg?1?·?min?1) terms, this new prediction equation displays minimal shrinkage. It should also demonstrate similar accuracy when it is applied to other samples that include participants of comparable age, body mass, and aerobic fitness level. This simple TMJ test and its corresponding regression model provides a relatively safe, convenient, and accurate way to predict VO2max in fit adults, ages 18 to 40 years.  相似文献   

13.

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   

14.
Purpose: The purpose of this study was to examine differences in heart rate recovery (HRRec) and oxygen consumption recovery (VO2 recovery) between young healthy-weight children and children with obesity following a maximal volitional graded exercise test (GXTmax). Method: Twenty healthy-weight children and 13 children with obesity completed body composition testing and performed a GXTmax. Immediately after the GXTmax, HRRec and VO2 recovery were measured each minute for 5 consecutive minutes. Results: There were no statistically significant group differences in HRRec for the 5 min following maximal exercise, Wilks’s Lambda = .885, F(4, 28) = 0.911, p = .471, between the healthy-weight children and children with obesity despite statistically significant differences in body fat percentage (BF%; healthy-weight children, 18.5 ± 6.1%; children with obesity, 41.1 ± 6.9%, p < .001) and aerobic capacity relative to body mass (VO2 peak; healthy-weight children, 46.8 ± 8.2 mL/kg/min; children with obesity, 31.9 ± 4.7 mL/kg/min, p < .001). There were statistically significant differences in VO2 recovery for the 5 min following exercise, Wilks’s Lambda = .676, F(4, 26) = 3.117, p = .032. There were no statistically significant correlations between HRRec and body mass index (BMI), BF%, VO2peak, or physical activity. Conclusions: In a healthy pediatric population, obesity alone does not seem to significantly impact HRRec, and because HRRec was not related to obesity status, BMI, or BF%, it should not be used as the sole indicator of aerobic capacity or health status in children. Using more than one recovery variable (i.e., HRRec and VO2 recovery) may provide greater insight into cardiorespiratory fitness in this population.  相似文献   

15.
The accumulation of bone mass during puberty is related with bone health in adulthood. This accumulation is influenced by diverse factors such as body mass index (BMI), maximal oxygen uptake (VO2 max), hours of training and years of sport practice. For this reason, the objective of this study is to analyse the influence of these variables on bone mass in young female athletes. The sample is formed of 120 healthy girls with ages between 9 and 13 (11.32?±?1.6?years old), divided into two groups depending on their BMI, VO2 max, hours of training and years of sport practice. The participants completed a series of tests to evaluate level of sexual development, body composition (fat mass, lean mass and bone mass) and physical condition. The results show higher values of total lean mass, total fat mass and percentage of body fat in the groups with higher BMI in prepubertal girls and pubertal girls (p?2 max, in the prepubertal group, girls with lower VO2 max had higher values of total fat mass (p?p?2 max also showed a higher total fat mass (p?相似文献   

16.
Carbohydrate (CHO) availability during endurance exercise seems to attenuate exercise-induced perturbations of cellular homeostasis and might consequently diminish the stimulus for training adaptation. Therefore, a negative effect of CHO intake on endurance training efficacy seems plausible. This study aimed to test the influence of carbohydrate intake on the efficacy of an endurance training program on previously untrained healthy adults. A randomized cross-over trial (8-week wash-out period) was conducted in 23 men and women with two 8-week training periods (with vs. without intake of 50g glucose before each training bout). Training intervention consisted of 4x45 min running/walking sessions/week at 70% of heart rate reserve. Exhaustive, ramp-shaped exercise tests with gas exchange measurements were conducted before and after each training period. Outcome measures were maximum oxygen uptake (VO2max) and ventilatory anaerobic threshold (VT). VO2max and VT increased after training regardless of CHO intake (VO2max: Non-CHO 2.6 ± 3.0 ml*min?1*kg?1 p = 0.004; CHO 1.4 ± 2.5 ml*min?1*kg?1 p = 0.049; VT: Non-CHO 4.2 ± 4.2 ml*min?1*kg?1 p < 0.001; CHO 3.0 ± 4.2 ml*min?1*kg?1 p = 0.003). The 95% confidence interval (CI) for the difference between conditions was between +0.1 and +2.1 ml*min?1*kg?1 for VO2max and between ?1.2 and +3.1 for VT. It is concluded that carbohydrate intake could potentially impair the efficacy of an endurance training program.  相似文献   

17.
Background: High-intensity interval training (HIIT) has been shown to improve cardiometabolic health during supervised lab-based studies but adherence, enjoyment, and health benefits of HIIT performed independently are yet to be understood. We compared adherence, enjoyment, and cardiometabolic outcomes after 8 weeks of HIIT or moderate-intensity continuous training (MICT), matched for energy expenditure, in overweight and obese young adults. Methods: 17 adults were randomized to HIIT or MICT. After completing 12 sessions of supervised training over 3 weeks, participants were asked to independently perform HIIT or MICT for 30 min, 4 times/week for 5 weeks. Cardiometabolic outcomes included cardiorespiratory fitness (VO2 peak), lipids, and inflammatory markers. Exercise enjoyment was measured by the validated Physical Activity Enjoyment Scale. Results: Exercise adherence (93.4?±?3.1% vs. 93.1?±?3.7%, respectively) and mean enjoyment across the intervention (100.1?±?4.3 vs. 100.3?±?4.4, respectively) were high, with no differences between HIIT and MICT (p?>?.05). Similarly, enjoyment levels did not change over time in either group (p?>?.05). After training, HIIT exhibited a greater decrease in low-density lipoprotein cholesterol than MICT (?0.66?mmol?L?1 vs. ?0.03?mmol?L?1, respectively) and a greater increase in VO2 peak than MICT (p?<?.05, +2.6?mL?kg?min?1 vs. +0.4?mL?kg?min?1, respectively). Interleukin-6 and C-reactive protein increased in HIIT (+0.5?pg?mL?1 and +?31.4?nmol?L?1, respectively) and decreased in MICT (?0.6?pg?mL?1 and ?6.7?nmol?L?1, respectively, p?<?.05). Conclusions: Our novel findings suggest that HIIT is enjoyable and has high unsupervised adherence rates in overweight and obese adults. However, HIIT may be associated with an increase in inflammation with short-term exercise in this population.  相似文献   

18.
ABSTRACT

Sedentary time (ST) has been inconsistently associated with adiposity and cardiorespiratory fitness in children in previous studies. We studied cross-sectional associations of ST, light physical activity (LPA), and moderate-to-vigorous physical activity (MVPA) with fat mass index (FMI) and cardiorespiratory fitness (estimated VO2max). Associations were evaluated with and without considering pattern of ST by bout length. We measured ST and activity by a wrist-worn accelerometer, FMI by bioelectrical impedance, and VO2max by Pacer test in 443 children (51.2% girls, 10.2 ± 0.6 years). Isotemporal substitution regression models estimated the effects of substituting ST, LPA, and MVPA on FMI and VO2max. Further models repeated analyses separating ST into short (<10 min) and long (≥10 min) bouts. Only replacing ST or LPA with MVPA was consistently associated with lower FMI and greater VO2max. When separated by bout length, only one unique association was found where replacing long ST bouts with short ST bouts was associated with lower FMI in girls only. In conclusion, activity pattern is associated with adiposity in girls and fitness in boys and girls. Separating ST into long and short ST bouts may be of minimal importance when assessing associations with adiposity and fitness using wrist-worn accelerometry in children.  相似文献   

19.
The purpose of this study was to examine the effect of the L-Alanyl-L-Glutamine dipeptide (AG) on cognitive function and reaction time (RT) following endurance exercise. Twelve male endurance athletes (23.5 ± 3.7 y; 175.5 ± 5.4 cm; 70.7 ± 7.6 kg) performed four trials, each consisting of running on a treadmill at 70% of VO2max for 1h, then at 90% of VO2max until exhaustion. One trial consisted of no hydration (DHY), another required ingestion of only a sports electrolyte drink (ED) and two trials required ingestion of a low dose (LD; 300 mg·500 ml?1) and high dose (HD) of AG (1 g·500ml?1) added to the ED. Cognitive function and reaction tests were administered pre- and post-exercise. Magnitude based inferences were used to analyze ? cognitive function and ? reaction test data. Results indicated that DHY had a possible negative effect on number of hits in a 60-sec reaction test compared to LD and HD, while ED appeared to have a negative effect compared to HD. Analysis of lower body quickness indicated that LD and HD were likely improved in comparison to DHY. Performance on the serial subtraction test appeared to be possibly better in ED than DHY, while other comparisons between groups regarding cognitive function were unclear. In conclusion, rehydrating with AG during submaximal exercise may maintain or enhance subsequent RT in upper and lower body activities compared to DHY. These same effects were not apparent when participants consumed ED.  相似文献   

20.
The purpose of this study was to determine if the counting talk test can be used to discern whether an individual is exercising above or at/below maximal lactate steady state. Twenty-two participants completed VO2peak and counting talk test incremental step tests followed by an endurance test at 65% of work rate at VO2peak (WRVO2peak). The change in relative count time during endurance exercise decreased in those exercising above maximal lactate steady state only (p < .01); however, this change was less than 1 second. Despite a significant correlation during the incremental step test, large changes in counting talk test performance and blood lactate concentration occurred at different points and there was considerable inter-individual variability in counting talk test performance at a given blood lactate concentration. These results suggest that the counting talk test cannot discern whether an individual is exercising above maximal lactate steady state and that it cannot be used to accurately prescribe intensities targeting specific blood lactate concentrations.  相似文献   

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