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1.
Carnitine is an essential co-factor in the catabolism of fats as an energy source. The primary purpose of this study was to investigate the effect of running a marathon on the metabolism of carnitine by endurance-trained athletes, and to evaluate the effect of carnitine administration on the performance of such exercise. The effects of marathon running on mitochondrial enzymes and cellular anti-oxidants were also examined to assess whether the expression of these activities is altered by exercise. Subjects were 10 experienced male marathon runners aged between 19 and 25 years. Running a marathon caused a fall in the plasma content of unesterified carnitine (37%) and an increase in the level of acetylcarnitine present (288%). Loading of the athletes with L-carnitine for 10 days before running a marathon abolished the exercise-induced fall in plasma-free carnitine (P less than 0.05) whilst amplifying the production of acetylcarnitine (P less than 0.05). Carnitine loading of the athletes studied made no detectable improvement in performance of the marathon (P greater than 0.05). Cytochrome oxidase, succinate cytochrome C reductase and superoxide dismutase activities present in skeletal muscle were unaltered by marathon running. However, such exercise caused a large increase in the tissue content of oxidized glutathione (189%) at the expense of reduced glutathione (-18%).  相似文献   

2.
To examine the influence of pre-warming on the physiological responses to prolonged intermittent exercise in ambient temperatures of 21.5?±?0.6°C and relative humidities of 35.7?±?5.4% (mean?±?s), six healthy men performed intermittent treadmill running (30-s bouts at 90% of maximal oxygen uptake separated by 30-s static recovery periods) to exhaustion after active pre-warming, passive pre-warming and pre-exercise rest (control). Exercise time to exhaustion was significantly different between all conditions (active, 51.8?±?7.2?min; passive, 38.5?±?11.1?min; control, 72.0?±?17.2?min; P <?0.05). These changes in performance time were closely associated with a significant decline in both the rate of heat storage and heat storage capacity (P <?0.05). Rectal temperature, heart rate and ratings of perceived exertion were significantly higher during exercise in the two pre-warming conditions than in the control condition (P <?0.05). Ratings of perceived exertion were also significantly higher during exercise following passive pre-warming compared with active pre-warming (P <?0.05). During exercise there were no significant differences in serum prolactin, plasma norepinephrine and plasma free fatty acid concentrations between conditions. We conclude that both active and passive pre-warming promote a reduction in prolonged intermittent exercise capacity in environmental temperatures of 21°C compared with pre-exercise rest. These performance decrements were dependent upon the mode of pre-warming and closely reflected alterations in body heat content.  相似文献   

3.

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   

4.
The aim of this study was to examine the effects of ingesting a carbohydrate‐electrolyte solution on endurance capacity during a prolonged intermittent, high‐intensity shuttle running test (PIHSRT). Nine trained male games players performed two exercise trials, 7 days apart. On each occasion, they completed 75 min exercise, comprising of five 15‐min periods of intermittent running, consisting of sprinting, interspersed with periods of jogging and walking (Part A), followed by intermittent running to fatigue (Part B). The subjects were randomly allocated either a 6.9% carbohydrate‐electrolyte solution (CHO) or a non‐carbohydrate placebo (CON) immediately prior to exercise (5 ml kg‐1 body mass) and every 15 min thereafter (2 ml kg‐1 body mass). Venous blood samples were obtained at rest, during and after each PIHSRT for the determination of glucose, lactate, plasma free fatty acid, glycerol, ammonia, and serum insulin and electrolyte concentrations. During Part B, the subjects were able to continue running longer when fed CHO (CHO = 8.9 ± 1.5 min vs CON = 6.7 ± 1.0 min; P < 0.05) (mean ± s.e.m.). These results show that drinking a carbohydrate‐electrolyte solution improves endurance running capacity during prolonged intermittent exercise.  相似文献   

5.
Abstract

The aim of the study was to explore pre-competition training practices of elite endurance runners. Training details from elite British middle distance (MD; 800 m and 1500 m), long distance (LD; 3000 m steeplechase to 10,000 m) and marathon (MAR) runners were collected by survey for 7 days in a regular training (RT) phase and throughout a pre-competition taper. Taper duration was [median (interquartile range)] 6 (3) days in MD, 6 (1) days in LD and 14 (8) days in MAR runners. Continuous running volume was reduced to 70 (16)%, 71 (24)% and 53 (12)% of regular levels in MD, LD and MAR runners, respectively (P < 0.05). Interval running volume was reduced compared to regular training (MD; 53 (45)%, LD; 67 (23)%, MAR; 64 (34)%, P < 0.05). During tapering, the peak interval training intensity was above race speed in LD and MAR runners (112 (27)% and 114 (3)%, respectively, P < 0.05), but not different in MD (100 (2)%). Higher weekly continuous running volume and frequency in RT were associated with greater corresponding reductions during the taper (R = ?0.70 and R = ?0.63, respectively, both P < 0.05). Running intensity during RT was positively associated with taper running intensity (continuous intensity; R = 0.97 and interval intensity; R = 0.81, both P < 0.05). Algorithms were generated to predict and potentially prescribe taper content based on the RT of elite runners. In conclusion, training undertaken prior to the taper in elite endurance runners is predictive of the tapering strategy implemented before competition.  相似文献   

6.
Abstract

In 219 recreational male runners, we investigated changes in body mass, total body water, haematocrit, plasma sodium concentration ([Na+]), and urine specific gravity as well as fluid intake during a 100-km ultra-marathon. The athletes lost 1.9 kg (s = 1.4) of body mass, equal to 2.5% (s = 1.8) of body mass (P < 0.001), 0.7 kg (s = 1.0) of predicted skeletal muscle mass (P < 0.001), 0.2 kg (s = 1.3) of predicted fat mass (P < 0.05), and 0.9 L (s = 1.6) of predicted total body water (P < 0.001). Haematocrit decreased (P < 0.001), urine specific gravity (P < 0.001), plasma volume (P < 0.05), and plasma [Na+] (P < 0.05) all increased. Change in body mass was related to running speed (r = ?0.16, P < 0.05), change in plasma volume was associated with change in plasma [Na+] (r = ?0.28, P < 0.0001), and change in body mass was related to both change in plasma [Na+] (r = ?0.36) and change in plasma volume (r = 0.31) (P < 0.0001). The athletes consumed 0.65 L (s = 0.27) fluid per hour. Fluid intake was related to both running speed (r = 0.42, P < 0.0001) and change in body mass (r = 0.23, P = 0.0006), but not post-race plasma [Na+] or change in plasma [Na+] (P > 0.05). In conclusion, faster runners lost more body mass, runners lost more body mass when they drank less fluid, and faster runners drank more fluid than slower runners.  相似文献   

7.
This study examined the effects of equal anaerobic and aerobic total work outputs on the relationship between reproductive hormones in men. Nine subjects performed three randomized trials on separate days: (1) 1 h period of rest (control), (2) 1 h continuous aerobic exercise (65% VO2 max), and (3) 1 h intermittent anaerobic exercise (which included 2 min exercise periods at 110% FO2 max). The total work output of the aerobic and anaerobic trials were equated. For the 8 h after each experimental trial, blood samples were collected hourly and analysed for testosterone, luteinizing hormone (LH), follicle‐stimulating hormone (FSH), prolactin and cortisol. Diet, physical activity and circadian influences were all controlled. Compared with the control, the aerobic and anaerobic trials significantly (P < 0.05) elevated testosterone, prolactin and cortisol; however, these changes were transient and returned to control levels within 1–2 h of recovery. Neither exercise produced significant (P > 0.05) changes from control for LH and FSH. The area under the hormonal response curves (AUC) was calculated for the 8‐h recovery period. The testosterone and LH AUC results did not differ (P > 0.05) among the trials (the FSH AUC was not calculated). The prolactin AUC for the aerobic and anaerobic trials were greater (P < 0.01) than the control trial. The cortisol AUC for the anaerobic trial was greater than both the control and aerobic trials (P < 0.05), but the aerobic and control trials did not differ from one another. Correlation analysis among the AUC results within each trial showed testosterone and LH to be significantly related during the control (r = 0.723, P < 0.05) and aerobic (r = 0.801, P < 0.01) trials, but not so during the anaerobic trial (r = 0.430, P > 0.05). No other significant correlations were found. The present findings suggest the relationship between testosterone and LH is affected by anaerobic exercise but not aerobic exercise. However, the effect of anaerobic exercise upon the testosterone‐LH relationship did not seem related to the concurrently induced prolactin or cortisol changes. Anaerobic exercise may produce some degree of temporary alteration within the testosterone‐LH component of the hypothalamic‐pituitary‐gonadal axis; however, the mechanism for this phenomenon remains unclear.  相似文献   

8.
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   

9.
Abstract

Exercise-induced muscle damage (EIMD), described as the acute weakness of the musculature after unaccustomed eccentric exercise, increases oxidative metabolism at rest and during endurance exercise. However, it is not known whether oxygen uptake during recovery from endurance exercise is increased when experiencing symptoms of EIMD. Therefore, the purpose of this study was to investigate the effects of EIMD on physiological and metabolic responses before, during and after sub-maximal running. After a 12 h fast, eight healthy male participants completed baseline measurements comprising resting metabolic rate (RMR), indirect markers of EIMD, 10 min of sub-maximal running and 30 min of recovery to ascertain excess post-exercise oxygen consumption (EPOC). Measurements were then repeated at 24 and 48 h after 100 Smith-machine squats. Data analysis revealed significant (P<0.05) increases in muscle soreness and creatine kinase (CK) and decreases in peak knee extensor torque at 24 and 48 h after squatting exercise. Moreover, RMR, physiological, metabolic and perceptual responses during sub-maximal running and EPOC were increased in the two days after squatting exercise (P<0.05). It is suggested that the elevated RMR was a consequence of a raised energy requirement for the degradation and resynthesis of damaged muscle fibres. The increased oxygen demand during sub-maximal running after muscle damage was responsible for the increase in EPOC. Individuals engaging in unaccustomed resistance exercise that results in muscle damage should be mindful of the increases in resting energy expenditure and increased metabolic demand to exercise in the days that follow.  相似文献   

10.
Abstract

Controversy exists whether custom-made insoles are more effective in reducing plantar loading compared to prefabricated insoles. Forty recreational athletes ran using custom-made, prefabricated, and the original insoles of their running shoes, at rest and after a fatigue run. Contact time, stride rate, and plantar loading parameters were measured. Neither the insole conditions nor the fatigue state modified contact time and stride rate. Addressing prevention of running injuries, post-fatigue loading values are of great interest. Custom-made insoles reduced the post-fatigue loading under the hallux (92 vs. 130 kPa, P < 0.05), medial midfoot (70 vs. 105 kPa, P < 0.01), and lateral midfoot (62 vs 96 kPa, P < 0.01). Prefabricated insoles provoked reductions in post-fatigue loading under the toes (120 vs. 175 kPa, P < 0.05), medial midfoot (71 vs. 105 kPa, P < 0.01), and lateral midfoot (68 vs. 96 kPa, P < 0.01). Regarding both study insoles, custom-made insoles reduced by 31% and 54% plantar loading under the medial and lateral heel compared to the prefabricated insoles. Finally, fatigue state did not influence plantar loading regardless the insole condition. In long-distance races, even a slight reduction in plantar loading at each foot strike may suppose a significant decrease in the overall stress experienced by the foot, and therefore the use of insoles may be an important protective mechanism for plantar overloading.  相似文献   

11.
The aim of this study was to examine the age-based, lower limb kinetics of running performances of endurance athletes. Six running trials were performed by 24 male athletes, who were distinguished by three age groupings (S35: 26–32 years, M50: 50–54 years, M60+: 60–68 years). Lower limb coordinate and ground reaction force data were collected using a nine camera infra-red system synchronised with a force plate. A slower anteroposterior (M ± SD S35 = 4.13 ± 0.54 m/s: M60+ = 3.34 ± 0.40 m/s, p < 0.05) running velocity was associated with significant (p < 0.05) decreases in step length and discrete vertical ground contact force between M60+and S35 athletes. The M60+athletes simultaneously generated a 32% and 42% reduction (p < 0.05) in ankle joint moment when compared to the M50 and S35 athletes and 72% (p < 0.05) reduction in knee joint stiffness when compared to S35 athletes. Age-based declines in running performance were associated with reduced stance phase force tolerance and generation that may be accounted for due to an inhibited force–velocity muscular function of the lower limb. Joint-specific coaching strategies customised to athlete age are warranted to maintain/enhance athletes' dynamic performance.  相似文献   

12.
Abstract

Pulmonary diffusing capacity (Dlco), together with spirometric variables, arterial oxygen tension (paO2) and cardiac output were determined before and at intervals after maximal arm cranking, treadmill running and erogmeter rowing. Independent of the type of exercise, Dlco increased immediately post‐exercise from a median 13.6 (range 7.3–16.3) to 15.1 (9.3–19.6) mmol min‐1 kPa‐1 (P <0.01). However, it decreased to 11.6 (6.9–15.5) mmol min‐1 kPa‐1 (P <0.01) after 24 h with cardiac output and paO2 at resting values, and Dlco normalized after 20 h. Thoracic electrical impedance at 2.5 and 100 kHz increased slightly post‐exercise, indicating a decrease in thoracic fluid balance, and there were no echocardiographic signs of left ventricular failure at the time of the decrease in Dlco. Also, active muscle (limb) circumference and volume, and an increase in haematocrit from 43.8 (38.0–47.0) to 47.1 (42.7–49.8) (P <0.01), had normalized at the time of the decrease in Dlco. Vital capacity, forced vital capacity, forced expiratory volume in 1 s, peak and peak mid‐expiratory flows did not change. However, total lung capacity increased from 6.8 (5.0–7.6) to 7.0 (5.1–7.8) litres (P <0.05) immediately after exercise and remained elevated at 6.9 (5.1–8.7) litres (P <0.05) when a decrease in Dlco was noted. The results demonstrate that independent of the type of maximal exercise, an approximate 15% reduction in Dlco takes place 2–3 h post‐exercise, which normalizes during the following day of recovery.  相似文献   

13.
We investigated how cytokines are implicated with overtraining syndrome (OTS) in athletes during a prolonged period of recovery. Plasma IL-6, IL-10, TNF-α, IL-1β, adipokine leptin, and insulin like growth factor-1 (IGF-1) concentrations were measured in overtrained (OA: 5 men, 2 women) and healthy control athletes (CA: 5 men, 5 women) before and after exercise to volitional exhaustion. Measurements were conducted at baseline and after 6 and 12 months. Inflammatory cytokines did not differ between groups at rest. However, resting leptin concentration was lower in OA than CA at every measurement (P < 0.050) but was not affected by acute exercise. Although IL-6 and TNF-α concentrations increased with exercise in both groups (P < 0.050), pro-inflammatory IL-1β concentration increased only in OA (P < 0.050) and anti-inflammatory IL-10 was greater in CA (P < 0.001). In OA, exercise-related IL-6 and TNF-α induction was enhanced during the follow-up (P < 0.050). IGF-1 decreased with exercise in OA (P < 0.050); however, no differences in resting IGF-1 were observed. In conclusion, low leptin level at rest and a pro-inflammatory cytokine response to acute exercise may reflect a chronic maladaptation state in overtrained athletes. In contrast, the accentuation of IL-6 and TNF-α responses to acute exercise seemed to associate with the progression of recovery from overtraining.  相似文献   

14.
Abstract

In this study, we examined the effects of different work:rest durations during 20 min intermittent treadmill running and subsequent performance. Nine males (mean age 25.8 years, s = 6.8; body mass 73.9 kg, s = 8.8; stature 1.75 m, s = 0.05; [Vdot]O2max 55.5 ml · kg?1 · min?1, s = 5.8) undertook repeated sprints at 120% of the speed at which [Vdot]O2max was attained interspersed with passive recovery. The work:rest ratio was constant (1:1.5) with trials involving either short (6:9 s) or long (24:36 s) work:rest exercise protocols (total exercise time 8 min). Each trial was followed by a performance run to volitional exhaustion at the same running speed. Testing order was randomized and counterbalanced. Heart rate, oxygen consumption, respiratory exchange ratio, and blood glucose were similar between trials (P > 0.05). Blood lactate concentration was greater during the long than the short exercise protocol (P < 0.05), whereas blood pH was lower during the long than the short exercise protocol (7.28, s = 0.11 and 7.30, s = 0.03 at 20 min, respectively; P < 0.05). Perceptions of effort were greater throughout exercise for the long than the short exercise protocol (16.6, s = 1.4 and 15.1, s = 1.6 at 20 min, respectively; P < 0.05) and correlated with blood lactate (r = 0.43) and bicarbonate concentrations (r = ?0.59; P < 0.05). Although blood lactate concentration at 20 min was related to performance time (r = ?0.56; P < 0.05), no differences were observed between trials for time to exhaustion (short exercise protocol: 95.8 s, s = 30.0; long exercise protocol: 92.0 s, s = 37.1) or physiological responses at exhaustion (P > 0.05). Our results demonstrate that 20 min of intermittent exercise involving a long work:rest duration elicits greater metabolic and perceptual strain than intermittent exercise undertaken with a short work:rest duration but does not affect subsequent run time to exhaustion.  相似文献   

15.
Male interscholastic swimmers (n = 8) completed a 4572 m training swim in 62 ±1.1 min (x ± s.e.) with terminal heart rate and blood lactate of 152 ± 6 beats min‐1 and 6.9±0.89 mM, respectively. Sweat rate (0.48±0.0951. h‐1) was lower than similar intensity cycling (1.5±0.13 1. h‐1) or running (1.1 ± 0.14 l.h‐1). Post‐swim serum urea N (11.6±0.71 mM) was elevated (P<0.05) vs pre‐swim (4.6±0.39 mM). Post‐swim urine volume (860±75 ml 24 h‐1) was reduced (P<0.07) and resulted in an elevated (P<0.05), but delayed (24–84 h), post‐exercise urea N excretion. Although the reduced urine and sweat production during the swim undoubtedly contributed to the elevated serum urea, there must be another explanation because together they could only account for 38% of the observed increase. On the basis of the magnitude of serum urea increase, it appears that the swim caused an increase in urea production (amino acid oxidation). The failure to observe larger increases in urinary urea during recovery indicates that either urea excretion following exercise continues for prolonged periods of time (>48 h) or another significant mode of nitrogen excretion exists.  相似文献   

16.
The onset of exercise facilitates an improvement in psychomotor performance until the second ventilatory threshold, after which performance is reduced. This inverted-U relationship appears valid for incremental and steady-state exercise, however, not for intermittent exercise. This study examined changes in psychomotor performance of team sport officials during a laboratory-based match simulation. Twelve elite Australian football (n = 5) and rugby league (n = 7) officials (32.5 ± 5.5 years; 180.0 ± 6.8 cm; 78.8 ± 7.6 kg) completed the match simulation on a non-motorised treadmill. Physiological measures were routinely taken, while psychomotor performance was assessed using the Eriksen flanker task (multiple-choice response time). Significant reductions (P < 0.05) were observed in distance covered and high-speed running during the second half when compared to the first. No significant differences (P > 0.05) in psychomotor performance at different time points were observed. Response time was significantly improved when running above 65% of maximal sprinting speed (P < 0.01). This data questions the application of the inverted-U hypothesis for intermittent exercise and suggests that the short high-intensity efforts may not result in the same physiological events that limit psychomotor performance during sustained high-intensity exercise. More so, the high-intensity efforts during the match protocol appeared to promote psychomotor performance during the intermittent exercise.  相似文献   

17.
This study investigated whether haematological markers differ between young and masters marathon participants, running at similar performance levels. Nine young (31.89 ± 4.96 years) and eight masters (63.13 ± 4.61 years) runners participated. At five time points (pre-race through 54 h post-race), a complete blood cell count, basic metabolic panel and creatine kinase (CK) isoenzyme panel were assessed. Race performance was standardised using the World Masters Association Age Grading Performance Tables. Total CK levels were elevated for all participants at all time points post-race (P < 0.001). The CK-isoenzyme MB% was elevated across groups at 6, 30 and 54 h post-race (P < 0.01, P < 0.01 and P < 0.05), with masters runners having a higher CK-MB% at 30 and 54 h (P < 0.05, P < 0.05). Total white blood cell and neutrophil counts were elevated through 6 h post-race (P < 0.001), with higher levels found in younger runners (P < 0.001). When considering all blood work, masters runners had a higher number of abnormal values at 6, 30 and 54 h post-race (P < 0.05, P < 0.01 and P < 0.05). In conclusion, masters runners demonstrated sustained CK-MB elevation, which may suggest greater cardiac stress. However, future studies using additional cardiac markers should be completed to confirm these findings. In addition, masters runners showed an increased number of laboratory values outside normal range, indicating the body’s reduced capacity to respond to marathon running.  相似文献   

18.
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   

19.
Abstract

This study investigated the participation and performance trends as well as the age and gender interaction at the Olympic distance ‘Zürich Triathlon’ (1.5?km swim, 40?km cycle and 10?km run) from 2000 to 2010 in 7,939 total finishers (1,666 females and 6,273 males). Female triathletes aged from 40 to 54 years significantly (P?<?0.05) increased their participation while the participation of younger females and males remained stable. Males of 50–54 years of age and females of 45–49 years of age improved their total race time. For elite top five overall triathletes, mean gender differences in swimming, cycling, running and overall race time were 15.2?±?4.6%, 13.4?±?2.3%, 17.1?±?2.5%, and 14.8?±?1.8%, respectively. For both elite and age group athletes, the gender difference in cycling time was significantly (P?<0.001) lower than for swimming and running. The gender difference in overall Olympic distance triathlon performance increased after the age of 35 years, which appeared earlier compared to long distance triathlon as suggested by previous studies. Future investigations should compare gender difference in performance for different endurance events across age to confirm a possible effect of exercise duration on gender difference with advancing age.  相似文献   

20.
The purpose of the present study was to assess fitness and running performance in a group of recreational runners (men, n = 18; women, n = 13). ‘Fitness’ was determined on the basis of their physiological and metabolic responses during maximal and submaximal exercise. There were strong correlations between VO2 max and treadmill running speeds equivalent to blood lactate concentrations of 2 mmol 1‐1’ (V‐2 mM) or 4 mmol 1‐1 (V‐4 mM), ‘relative running economy’ and 5 km times (r = 0.84), but modest and non‐significant correlations between muscle fibre composition and running performance. The results of the submaximal exercise tests suggested that the female runners were as well trained as the male runners. However, the men still recorded faster 5 km times (19.20 ± 1.97 min vs 20.97 ± 1.70 min; P <0.05). Therefore the results of the present study suggest that the faster performance times recorded by the men were best explained by their higher VO2 max values, rather than their training status per se.  相似文献   

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