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111.
The hormonal responses of nine male, strength athletes to strength exercise were examined. The athletes performed one moderate-
and one high-intensity strength exercise workout. In the high-intensity workout, the load was 100% of each subject's three-repetition
maximum (3-RM) for squats and front squats, and 100% of each subject's six-repetition maximum (6-RM) for leg extensions. In
the moderate-intensity workout, the load was 70% of the high-intensity protocol. Rest periods between sets were 4–6 min for
both workouts. Blood samples were taken before, 30 min into, and every 15 min for the 1st h after exercise, and then 3, 7,
11, 22 and 33 h after exercise, thus allowing examination of both the acute and prolonged hormonal responses. Blood samples
were analyzed for testosterone, luteinizing hormone (LH), follicle stimulating hormone (FSH), cortisol, adrenocorticotrophic
hormone (ACTH), growth hormone (GH), insulin-like growth factor (IGF-1), insulin, sex hormone binding globulin, creatine kinase,
total protein, glucose and lactate. The acute responses of testosterone and cortisol were greater during the high-intensity
protocol as compared to the moderate-intensity protocol. The cortisol response was associated with an increase in ACTH concentration.
LH and FSH showed no response to either protocol. Acute GH responses were not different between protocols. There were great
inter-individual differences in acute GH responses to both protocols. There were no significant differences between protocols
with regard to prolonged responses for any hormone. In both trials, IGF-1 concentrations were significantly lower at 0800 hours
the morning after exercise as compared to concentrations found at 0800 hours the morning before exercise. The mechanisms responsible
for reducing IGF-1 concentration in these trials are unclear, and it is not known if this reduction observed 22 hours after
exercise is of physiological significance.
Accepted: 13 December 1999 相似文献
112.
To determine vasodilatory responsiveness we measured forearm blood flow (FBF) following reactive hyperemia (RH), prior to
and following a bout of maximal aerobic exercise in endurance- (n=14) and resistance-trained men (n=10). Both groups were similar in height, body mass, and percentage body fat. Using strain-gauge plethysmography, resting
FBF was higher in the resistance-trained group [4.82 (0.84) vs 3.33 (1.17) ml min−1 100 ml−1 of tissue; P<0.05]. However, the resistance-trained group had a 17%–29% lower pre-exercise FBF response to RH for the first 45 s (P<0.05). Following the maximal exercise bout there were no group differences in FBF. Post-exercise FBF was higher compared
to pre-exercise values in both the endurance- (P<0.001) and resistance- (P<0.01) trained groups. Endurance-trained men appear to have a greater peak vasodilatory capacity compared to resistance-trained
men, and acute maximal exercise increased the vasodilatory capacity in both groups. Acute exercise also equalized the peak
vasodilatory response between the endurance- and resistance-trained groups, suggesting the potential for flow-mediated vasodilatation
was similar for both groups.
Electronic Publication 相似文献
113.
In an effort to assess the effect of ambient temperature on the gross efficiency (Effg) of step exercise 12 subjects performed a modified step test either at —15 °C or 21°C ascending to three different heights (corresponding to light, moderate and heavy work), for 20 min each with a frequency of 18 steps min-1. Heart rate (HR), rectal temperature, skin temperatures and heat flux from skin were continuously measured. Oxygen consumption was measured during the last 5 min of each step height and perceptions of thermal sensation were recorded. The results indicate that, while using conventional clothing adequate in these temperatures, Effg is altered in a contradictory manner. At —15°C Effg increased with increasing work load, whereas at 21°C it decreased when the work load increased. The highest Effg (heavy work at —15°C and light work at 21°C) values are reflected as rather similar rectal temperatures (37.4–37.7°C) and identical mean skin temperatures (32.8 °C) as well as the same (slightly warm) thermal sensation of the legs. At — 15 °C the lowest Effg in light work was probably hue to the need to warm up the muscles. At 21°C, on the contrary, the activation of heat dissipation systems was probably responsible for the lowest Effg in heavy work. 相似文献
114.
Castellani JW Armstrong LE Kenefick RW Pasqualicchio AA Riebe D Gabaree CL Maresh CM 《European journal of applied physiology》2001,84(1-2):42-47
It is yet unknown how upper body exercise combined with high ambient temperatures affects plasma testosterone and cortisol
concentrations and furthermore, how these hormones respond to exercise in people suffering spinal cord injuries. The purpose
of this study was to characterize plasma testosterone and cortisol responses to upper body exercise in wheelchair athletes
(WA) compared to able-bodied individuals (AB) at two ambient temperatures. Four WA [mean age 36 (SEM 13) years, mean body
mass 66.9 (SEM 11.8) kg, injury level T7–T11], matched with five AB [mean age 33.4 (SEM 8.9) years, mean body mass 72.5 (SEM 13.1) kg] exercised (cross-over design) for
20 min on a wheelchair ergometer (0.03 kg resistance · kg−1 body mass) at 25 °C and 32 °C. Blood samples were obtained before (PRE), at min 10 (MID), and min 20 (END) of exercise. No
differences were found between results obtained at 25 °C and 32 °C for any physiological variable studied and therefore these
data were combined. Pre-exercise testosterone concentration was lower (P < 0.05) in WA [18.3 (SEM 0.9) nmol · l−1] compared to AB [21.9 (SEM 3.6) nmol · l−1], and increased PRE to END only in WA. Cortisol concentrations were similar between groups before and during exercise, despite
higher rectal temperatures in WA compared to AB, at MID [37.21 (SEM 0.14) and 37.02 (SEM 0.08)°C, respectively] and END
[37.36 (SEM 0.16) and 37.19 (SEM 0.10)°C, respectively]. Plasma norepinephrine responses were similar between groups. In conclusion,
there were no differences in plasma cortisol concentrations, which may have been due to the low relative exercise intensities
employed. The greater exercise response in WA for plasma testosterone should be confirmed on a larger population. It could
have been the result of the lower plasma testosterone concentrations at rest in our group.
Accepted: 4 September 2000 相似文献
115.
H. Pekkarinen H. Tukiainen H. Litmanen J. Huttunen T. Karstu E. Länsimies 《European journal of applied physiology》1989,58(8):821-825
Summary In order to understand more fully the effect on pulmonary function of whole body exposure to cold during submaximal exercise,
we measured pulmonary function indices in ten healthy male students and ten healthy male forestry workers of similar age following
submaximal treadmill walking at different temperatures in a climatic chamber. After measuring the maximal aerobic capacity
with a cycle ergometer test, the subjects had to walk on four separate occasions in the climatic chamber at an intensity of
70%–75% of their individual maximal heart rate; the first at normal room temperature and then randomly, either at 0°C or at
−20°C, and vice versa. The duration of each walk was 8 min. Finally, each subject had to walk in the chamber at −20° C for
17 min. Flow volume spirometry was performed at room temperature 1, 5, 10, and 20 min after exercise and the values were compared
to baseline values taken prior to the last walking test. There were only minor changes in pulmonary function indices following
exercise at different temperatures. Only one student showed a reduction of over 15% in peak expiratory flow rate after an
8-min walk at −20° C. It seems that submaximal exercise of short duration, even at a temperature as low as −20° C, does not
impair pulmonary function in healthy young men. 相似文献
116.
Abstract Data on the metabolic responses to repeated endurance exercise sessions are limited. Thus, the aims of this study were to examine (1) the impact of prior exercise on metabolic responses to a subsequent exercise session and (2) the effect of different recovery periods between two daily exercise sessions on metabolic responses to the second bout of exercise. Nine male elite athletes participated in four 25-h trials: one bout of exercise (ONE), two bouts of exercise separated by 3 h of rest and one meal (SHORT), two bouts of exercise separated by 6 h of rest and two meals (LONG), and a trial with no exercise (REST). All exercise bouts consisted of 10 min cycling at 50% followed by 65 min at 75% of maximal O2 uptake. Compared to no prior exercise (ONE), a previous bout of exercise (SHORT) was followed by higher mean O2 uptake, heart rate (HR), rectal temperature (TR), excess post-exercise oxygen consumption and lower respiratory exchange ratio (R) during and after a similar exercise session 3 h later. A longer rest interval between the two exercise bouts (6 h versus 3 h) and an additional meal resulted in a decrease in O2 uptake, HR, TR and an increase in R during the second bout of exercise, but no effects on post-exercise metabolism were found. Thus, augmented metabolic stress was observed when strenuous exercise was repeated after only 3 h of recovery, but this was attenuated when a longer recovery period including an additional meal was provided between the exercise sessions. 相似文献
117.
Exercise motivation and adherence in cancer survivors after participation in a randomized controlled trial: An attribution theory perspective 总被引:1,自引:0,他引:1
Courneya KS Friedenreich CM Sela RA Quinney HA Rhodes RE Jones LW 《International journal of behavioral medicine》2004,11(1):8-17
The purpose of this study was to examine postprogram exercise motivation and adherence in cancer survivors who participated
in the Group Psychotherapy and Home-Based Physical Exercise (GROUP-HOPE; Courneya, Friedenreich, Sela, Quinney, & Rhodes,
2002) trial. At the completion of the GROUP-HOPE trial, 46 of 51 (90%) participants in the exercise group completed measures
of attribution theory constructs. A5-week follow-up self-report of exercise wasthen completed by 30 (65%) participants. Correlational
analyses indicated that program exercise, perceived success, expected success, and affective reactions were strong predictors
of postprogram exercise. In multivariate stepwise regression analyses, program exercise and perceived successwere the strongest
predictors of postprogram exercise. Additionally, perceived success was more important than objective success in understanding
the attribution process, and it interacted with personal control to influence expected success and negative affect. Finally,
postprogram quality of life and changes in physical fitness were correlates of perceived success. We concluded that attribution
theory may have utility for understanding postprogram exercise motivation and adherence in cancer survivors. 相似文献
118.
Summary In vitro CO2 dissociation curves for oxygenated whole blood were determined in 19 healthy male subjects at rest and during submaximal
and maximal bicycle work. Hemoglobin concentration and blood lactate increased with increasing work load and accordingly buffer
value of the whole blood increased while bicarbonate and Base Excess (BE) decreased, resulting in a downward shift of the
CO2 dissociation curve during exercise. Despite the marked increase in buffer values of the blood, the slopes of the CO2 dissociation curves during exercise were found to be about the same as those obtained at rest. It was inferred that the increasing
effect of increased buffer value, on the dissociation slope, was essentially compensated by the decreasing effect of diminished
bicarbonate content. The advantages of this relatively constant CO2 dissociation slope for the indirect measurement of cardiac output by the Fick principle are discussed. 相似文献
119.
Mourot L Hintzy F Messonier L Zameziati K Belli A 《European journal of applied physiology》2004,93(3):325-332
This study proposed a non-invasive method to determine the gross (GE, no baseline correction), net (NE, resting metabolism as the baseline correction) and work (WE, unloaded cycling as the baseline correction) efficiencies during cycling at an intensity higher than the maximal aerobic power (MAP). Twelve male subjects performed two exercises consisting of 4 min at 50% MAP followed either by 8 min at 63% MAP or by 8 sequences of 60 s divided into 10 s at 130% MAP and 50 s at 50% MAP (i.e., 63% MAP on average). Oxygen uptake was continuously measured to calculate GE, NE and WE at 50%, 63% and 130% MAP, and the data presented as the means and standard deviations. The GE values were 18.2%, 19.1%, 22.7%, the NE values were 22.4%, 22.8%, 24.3% and the WE values were 34.2%, 31.4% and 27.2% at 50%, 63% and 130% MAP, respectively. The GE and NE increased (P<0.001) whereas the WE decreased (P<0.001) with each increment in power output. The GE was lower than the NE (P<0.001) at 50% and 63% MAP and than the WE (P<0.001) at all intensities. The NE was lower (P<0.001) than the WE at 50% and 63% MAP. These results showed that (1) efficiency index values obtained during supra-maximal exercise were consistent with previous proposals and (2) the efficiency-power output relationships were not limited to sub-maximal intensity levels but were confirmed at higher power output. 相似文献
120.
The effect of physical training on the cutaneous vascular response during transient exercise load is unclear. We determined the phase response and amplitude response of cutaneous vascular conductance (CVC) in the hand during sinusoidal exercise in endurance exercise-trained and untrained subjects. Subjects exercised on a cycle ergometer with a sinusoidal load for 32 min. The load variation ranged from 10% [23 (1) W in the trained group, 19 (1) W in the untrained group] to 60% [137 (4) W, 114 (6) W] of peak O2 uptake, and five different time periods (1, 2, 4, 8, and 16 min) were selected. Skin blood flow in the dorsal hand and palm were monitored by laser-Doppler flowmetry. CVC was evaluated from the ratio of blood flow to mean arterial pressure. During sinusoidal exercise, the amplitude of CVC was smaller in the dorsal hand than palm for shorter periods (1, 2, and 4 min) (P<0.05). The phase lag of CVC was smaller in the dorsal hand than palm for longer periods (8 and 16 min) (P<0.05). The amplitude response did not differ significantly between the two groups. The phase lag of CVC in the dorsal hand (P<0.05) and palm (P=0.06) was larger in the trained group than untrained group. These findings suggest that glabrous and nonglabrous skin vascular responses in the hand differ during transient exercise load, and physically trained subjects show a slower vascular response in the two skin areas to exercise stimulation than do untrained subjects. 相似文献