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41.
Effects of long duration exercise on cognitive function, blood glucose, and counterregulatory hormones in male cyclists 总被引:2,自引:0,他引:2
Grego F Vallier JM Collardeau M Bermon S Ferrari P Candito M Bayer P Magnié MN Brisswalter J 《Neuroscience letters》2004,364(2):76-80
Electrocortical effects of long duration exercise on cognitive function were investigated by analyzing P300 amplitude and latency changes during a 3-h cycling exercise. P300 components were measured in 12 well-trained cyclists and blood glucose, cortisol, insulin, glycerol, and free fatty acids (FFAs) epinephrine and norepinephrine were analyzed. Results indicated that P300 components were affected by exercise with a temporary increase in amplitude between the 1st and the 2nd hour and an increase in latency after 2 h of exercise concomitant with some hormonal changes, including an increase in cortisol and epinephrine and a decrease in blood glucose. These findings suggest a combined effect of arousal and central fatigue on electrocortical indices of cognitive function during acute physical exercise. 相似文献
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Bernard T Vercruyssen F Mazure C Gorce P Hausswirth C Brisswalter J 《European journal of applied physiology》2007,99(2):103-111
The aim of this study was to investigate the metabolic responses to variable versus constant-intensity (CI) during 20-km cycling
on subsequent 5-km running performance. Ten triathletes, not only completed one incremental cycling test to determine maximal
oxygen uptake and maximal aerobic power (MAP), but also three various cycle-run (C–R) combinations conducted in outdoor conditions.
During the C–R sessions, subjects performed first a 20-km cycle-time trial with a freely chosen intensity (FCI, ∼80% MAP)
followed by a 5-km run performance. Subsequently, triathletes were required to perform in a random order, two C–R sessions
including either a CI, corresponding to the mean power of FCI ride, or a variable-intensity (VI) during cycling with power
changes ranging from 68 to 92% MAP, followed immediately by a 5-km run. Metabolic responses and performances were measured
during the C–R sessions. Running performance was significantly improved after CI ride (1118 ± 72 s) compared to those after
FCI ride (1134 ± 64 s) or VI ride (1168 ± 73 s) despite similar metabolic responses and performances reported during the three
cycling bouts. Moreover, metabolic variables were not significantly different between the run sessions in our triathletes.
Given the lack of significant differences in metabolic responses between the C–R sessions, the improvement in running time
after FCI and CI rides compared to VI ride suggests that other mechanisms, such as changes in neuromuscular activity of peripheral
skeletal muscle or muscle fatigue, probably contribute to the influence of power output variation on subsequent running performance. 相似文献
43.
The aim of this study was to evaluate the energy demands of sailing the new Neilpryde RS:X Olympic windsurf board. Ten skilled male subjects performed an exhaustive incremental treadmill test to determine their maximal physiological parameters. Thereafter, four tests were performed in a randomised order using two wind conditions, light [2-4 ms(-1) (4-8 knots)] and strong: [9-11 ms(-1)(16-22 knots)]. Oxygen consumption (VO2, ml min(-1) kg(-1)), blood lactate concentration ([la](b), mmol l(-1)), and time spent pumping (% total time) were recorded during 10 min of up-wind leg and during 6 min of down-wind leg. The results indicate that sailing on RS:X is associated with a high level of energy demand using both aerobic and anaerobic pathways whatever the wind conditions. During the down-wind leg, VO2, (ml min(-1) kg(-1)), [la](b) (mmol l(-1)), and time spent pumping (% total time) values for the light and strong wind conditions were 56.5 +/- 5.9 versus 55.5 +/- 3.6; 10.2 +/- 1.5 versus 9.6 +/- 2.3, and 69 +/- 5 versus 64 +/- 2%, respectively. In contrast, during up-wind leg the same parameters for light and strong wind were 53.9 +/- 4.5 versus 40.4 +/- 7.2; 9.7 +/- 2.8 versus 5.0 +/- 2.7 and 66 +/- 3 versus 37 +/- 8%, respectively. During the up-wind leg with strong wind conditions, less time was spent pumping (p < 0.05), mean oxygen consumption values were close to 60% VO2max and post-exercise blood lactate was less than 50% maximal lactate concentration. These results could be related to the time spent in pumping action, involving whole body activity. When sailing with the RS:X board, the physiological demand seems to be higher than with the previous official Olympic windsurf board [Mistral One Design (MOD)]. This difference could be mainly attributed to the specific biomechanical constraints induced by each board characteristic. 相似文献
44.
Louis J Hausswirth C Easthope C Brisswalter J 《European journal of applied physiology》2012,112(2):631-640
The purpose of this study was to test the effect of a 3-week strength training program of knee extensor muscles on cycling
delta efficiency in master endurance athletes. Nine master (age 51.5 ± 5.5 years) and 8 young (age 25.6 ± 5.9 years) endurance
athletes with similar training levels participated in this study. During three consecutive weeks, all the subjects were engaged
in a strength training program of the knee extensor muscles. Every week, they performed three training sessions consist of
10 × 10 knee extensions at 70% of maximal repetition with 3 min rest between in a leg extension apparatus. Maximal voluntary
contraction torque (MVC torque) and force endurance (End) were assessed before, after every completed week of training, and
after the program. Delta efficiency (DE) in cycling was evaluated before and after the training period. Before the training
period, MVC torque, End, and DE in cycling were significantly lower in masters than in young. The strength training induced
a significant improvement in MVC torque in all the subjects, more pronounced in masters (+17.8% in masters vs. +5.9% in young,
P < 0.05). DE in cycling also significantly increased after training in masters, whereas it was only a trend in young. A significant
correlation (r = 0.79, P < 0.01) was observed between MVC torque and DE in cycling in masters. The addition of a strength training program for the
knee extensor muscles to endurance-only training induced a significant improvement in strength and cycling efficiency in master
athletes. This enhancement in muscle performance alleviated all the age-related differences in strength and efficiency. 相似文献
45.
Endurance exercise immediately before sea diving reduces bubble formation in scuba divers 总被引:1,自引:0,他引:1
Castagna O Brisswalter J Vallee N Blatteau JE 《European journal of applied physiology》2011,111(6):1047-1054
Previous studies have observed that a single bout of exercise can reduce the formation of circulating bubbles on decompression
but, according to different authors, several hours delay were considered necessary between the end of exercise and the beginning
of the dive. The objective of this study was to evaluate the effect of a single bout of exercise taken immediately before
a dive on bubble formation. 24 trained divers performed open-sea dives to 30 msw depth for 30 min followed by a 3 min stop
at 3 msw, under two conditions: (1) a control dive without exercise before (No-Ex), (2) an experimental condition in which
subjects performed an exercise before diving (Ex). In the Ex condition, divers began running on a treadmill for 45 min at
a speed corresponding to their own ventilatory threshold 1 h before immersion. Body weight, total body fluid volume, core
temperature, and volume of consumed water were measured. Circulating bubbles were graded according to the Spencer scale using
a precordial Doppler every 30 min for 90 min after surfacing. A single sub-maximal exercise performed immediately before immersion
significantly reduces bubble grades (p < 0.001). This reduction was correlated not only to sweat dehydration, but also to the volume of water drunk at the end of
the exercise. Moderate dehydration seems to be beneficial at the start of the dive whereas restoring the hydration balance
should be given priority during decompression. This suggests a biphasic effect of the hydration status on bubble formation. 相似文献
46.
Vercruyssen F Blin N L'huillier D Brisswalter J 《European journal of applied physiology》2009,105(1):103-109
To evaluate the physiological demands of kitesurfing, ten elite subjects performed an incremental running test on a 400-m
track and a 30-min on-water crossing trial during a light crosswind (LW, 12–15 knots). Oxygen uptake was estimated from the heart rate (HR) recorded during the crossing trial using the individual HR- relationship determined during the incremental test. Blood lactate concentration [Lab] was measured at rest and 3 min after the exercise completion. Mean HR and estimated values represented, respectively 80.6 ± 7.5% of maximal heart rate and 69.8 ± 11.7% of maximal oxygen uptake for board speeds
ranging from 15 to 17 knots. Low values for [Lab] were observed at the end of crossing trial (2.1 ± 1.2 mmol l−1. This first analysis of kitesurfing suggests that the energy demand is mainly sustained by aerobic metabolism during a LW
condition. 相似文献
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Laura Pomportes Karen Davranche Ioanna Brisswalter Arnaud Hays Jeanick Brisswalter 《Nutrients》2015,7(1):196-208
The aim of this study was to assess cognitive performance and heart rate variability (HRV) following the ingestion of either a multi-vitamin-mineral preparation supplemented with 300 mg guarana (Ac); a caffeine supplement (C) or a placebo supplement (Pl). Fifty-six subjects took part in a randomized, double-blind crossover design, consisting of three experimental sessions ran on a different day. Cognitive performance was assessed using a go/no-go task and a simple reaction time (SRT) task. HRV was assessed in the time domain (RMSSD) and in the frequency domain (HF) and cognitive tasks were performed before ingestion, 15 min after ingestion and then every 15 min over the course of 3 h. Responses were faster (without change in accuracy) when the go/no-go task was performed between 30 and 90 min after ingestion of Ac (4.6% ± 0.8%, p < 0.05). No effect was observed on SRT task. A significant decrease in HRV was observed during the first hour under C and Pl, whereas HRV remained stable under Ac. The results suggest that the ingestion of a multi-vitamin-mineral with added guarana improves decision-making performance and is accompanied by a stable autonomic nervous system regulation during the first hour. 相似文献