共查询到20条相似文献,搜索用时 31 毫秒
1.
Carlsson L Lind B Laaksonen MS Berglund B Brodin LÅ Holmberg HC 《European journal of applied physiology》2011,111(6):905-913
The aim here was to employ color tissue velocity imaging (TVI), to test the hypothesis that highly trained endurance athletes
exhibit enhanced systolic function of the left ventricular (LV) myocardium both at rest and during combined arm-and-leg exercise
in comparison with untrained subjects. For each of the ten elite male (EG) and ten matched control participants (CG), LV dimensions
and systolic function were assessed at rest using echocardiography. Subsequently, these subjects exercised continuously on
a combined arm-and-leg cycle ergometer for 3 min each at 50, 60, 70, 80, 90 and 100% of VO2max. Oxygen uptake, heart rate, systolic blood pressure (SBP) and peak contraction systolic velocities of the LV myocardium (PSV)
were recorded in the end of each level. At rest, the trained and untrained groups differed with respect to LV dimensions,
but not systolic function. At 60–100% VO2max, the EG group demonstrated both higher PSV and SBP. The observation that the EG athletes had higher PSV than CG during exercise
at 60–100% VO2max, but not at rest or at 50% of VO2max, suggested an enhanced systolic capacity. This improvement is likely to be due to an enhanced inotropic contractility, which
only becomes apparent during exercise. 相似文献
2.
Kippelen P Caillaud C Robert E Masmoudi K Préfaut C 《Pflügers Archiv : European journal of physiology》2002,444(3):397-404
Endogenous nitric oxide (NO) is an important mediator of vasodilatation, bronchodilatation and lung inflammation. We hypothesised that the exhaled NO level may be modified in some endurance-trained athletes during and after intense exercise. Nine athletes with exercise-induced hypoxaemia (EIH), 12 athletes without EIH and 10 untrained subjects exercised for 15 min at 90% maximal oxygen consumption (VO(2)max). Exhaled NO was measured during exercise, and after 1 h and 22 h of recovery. Exhaled NO concentration ( C(NO)) decreased significantly during exercise in all subjects and returned to basal values after 1 h of recovery with no further modification. Exhaled NO output (V(NO)) rose significantly during exercise, rapidly dropped down following exercise and was similar to resting values after 1 h and 22 h of recovery. The results also showed that C(NO) and V(NO) were significantly lower in the athletes with EIH in comparison with the untrained subjects (V(NO) was 5.32 +/- 0.77 nmol/min versus 3.61 +/- 0.72 nmol/min at rest, 18.52 +/- 1.50 nmol/min versus 15.00 +/- 2.06 nmol/min during heavy exercise, and 5.52 +/- 1.04 nmol/min versus 3.79 +/- 0.76 nmol/min after 22 h recovery, in untrained subjects and EIH athletes, respectively). These findings do not confirm the hypothesis of pulmonary inflammation associated with EIH. However, potential NO epithelial down-regulation may occur and contribute to the development of gas exchange abnormality in some endurance-trained athletes. 相似文献
3.
P. D. Line K. Kvernebo J. Helgerud F. Ingjer 《European journal of applied physiology》1992,64(6):508-512
Summary Aerobic endurance capacity is partly dependent on blood supply to and metabolic capacity of the active muscles. Recordings of lower limb skin postocclusive hyperaemia with laser Doppler flowmetry can differentiate between patients with lower limb atherosclerosis and healthy controls. In this study, we investigated the relationship between aerobic endurance, calf volume, common femoral artery diameter and time properties of the postocclusive laser Doppler curve. A group of 16 healthy male subjects with values for aerobic endurance which varied from those of untrained men to elite endurance trained athletes were examined. Duration of laser Doppler recorded skin postocclusive hyperaemia was significantly correlated to both aerobic power and anaerobic threshold (P<0.01). Hyperaemia in subjects with large common femoral artery diameter was of shorter duration (P<0.05). The peak and mean body mass related blood flow during hyperaemia was correlated to anaerobic threshold (P<0.05). These results were in agreement with previous studies indicating an effect of endurance training on the blood supply to the muscles concerned. 相似文献
4.
Leyk D Gorges W Ridder D Wunderlich M Rüther T Sievert A Essfeld D 《European journal of applied physiology》2007,99(4):415-421
Hand-grip strength has been identified as one limiting factor for manual lifting and carrying loads. To obtain epidemiologically
relevant hand-grip strength data for pre-employment screening, we determined maximal isometric hand-grip strength in 1,654
healthy men and 533 healthy women aged 20–25 years. Moreover, to assess the potential margins for improvement in hand-grip
strength of women by training, we studied 60 highly trained elite female athletes from sports known to require high hand-grip
forces (judo, handball). Maximal isometric hand-grip force was recorded over 15 s using a handheld hand-grip ergometer. Biometric
parameters included lean body mass (LBM) and hand dimensions. Mean maximal hand-grip strength showed the expected clear difference
between men (541 N) and women (329 N). Less expected was the gender related distribution of hand-grip strength: 90% of females
produced less force than 95% of males. Though female athletes were significantly stronger (444 N) than their untrained female
counterparts, this value corresponded to only the 25th percentile of the male subjects. Hand-grip strength was linearly correlated
with LBM. Furthermore, both relative hand-grip strength parameters (F
max/body weight and F
max/LBM) did not show any correlation to hand dimensions. The present findings show that the differences in hand-grip strength
of men and women are larger than previously reported. An appreciable difference still remains when using lean body mass as
reference. The results of female national elite athletes even indicate that the strength level attainable by extremely high
training will rarely surpass the 50th percentile of untrained or not specifically trained men. 相似文献
5.
Félix Gómez-Gallego Jonatan R. Ruiz Amaya Buxens Marta Artieda David Arteta Catalina Santiago Gabriel Rodríguez-Romo José I. Lao Alejandro Lucia 《European journal of applied physiology》2009,107(5):565-569
The NOS3 gene is a candidate to explain individual variations in health and exercise related phenotypes. We compared genotypic and
allelic frequencies of the NOS3 −786 T/C polymorphism (rs2070744) in three groups of men of the same Caucasian (Spanish) descent: (i) elite endurance athletes
(cyclists, runners; N = 100); (ii) elite power athletes (jumpers, throwers, sprinters; N = 53) and (iii) non-athletic controls (N = 100). The frequency of the TT genotype was significantly higher in power athletes (57%) than in the endurance (33%, P = 0.017) or control group (34%, P = 0.026). The frequency of the T allele was also higher in power sportsmen (71%) than in their endurance (55%, P = 0.003) and control referents (56%, P = 0.015). No differences were observed between control and endurance groups. In summary, the −786 T/C polymorphism of the
NOS3 gene seems to be associated with elite performance in power-oriented athletic events (throwing, jumping, sprinting), with
the T allele exerting a beneficial effect. The mechanism by which this allele variant might benefit power performance remains
to be elucidated. 相似文献
6.
The effects of resistance exercise combined with vascular occlusion on muscle function were investigated in highly trained
athletes. Elite rugby players (n=17) took part in an 8 week study of exercise training of the knee extensor muscles, in which low-intensity [about 50% of
one repetition maximum] exercise combined with an occlusion pressure of about 200 mmHg (LIO, n=6), low-intensity exercise without the occlusion (LI, n=6), and no exercise training (untrained control, n=5) were included. The exercise in the LI group was of the same intensity and amount as in the LIO group. The LIO group showed
a significantly larger increase in isokinetic knee extension torque than that in the other two groups (P<0.05) at all the velocities studied. On the other hand, no significant difference was seen between LI and the control group.
In the LIO group, the cross-sectional area of knee extensors increased significantly (P<0.01), suggesting that the increase in knee extension strength was mainly caused by muscle hypertrophy. The dynamic endurance
of knee extensors estimated from the decreases in mechanical work production and peak force after 50 repeated concentric contractions
was also improved after LIO, whereas no significant change was observed in the LI and control groups. The results indicated
that low-intensity resistance exercise causes, in almost fully trained athletes, increases in muscle size, strength and endurance,
when combined with vascular occlusion.
Electronic Publication 相似文献
7.
8.
Helge JW Biba TO Galbo H Gaster M Donsmark M 《European journal of applied physiology》2006,97(5):566-572
During exercise, triacylglycerol (TG) is recruited in skeletal muscles. We hypothesized that both muscle hormone-sensitive lipase (HSL) activity and TG recruitment would be higher in trained than in untrained subjects in response to prolonged exercise. Healthy male subjects (26 ± 1 years, body moss index 23.3 ± 0.5 kg m−2), either untrained (N = 8, VO2max 3.8 ± 0.2 l min−1) or trained (N = 8, VO2max 5.1 ± 0.1 l min−1), were studied. Before and after 3-h exercise (58 ± 1% VO2max), a biopsy was taken. Muscle citrate synthase (32 ± 2 vs. 47 ± 6 μmol g−1 min−1 d.w.) and β-hydroxy-acyl-CoA-dehydrogenase (38 ± 3 vs. 52 ± 5 μmol g−1 min−1 d.w.) activities were lower in untrained than in trained subjects (p < 0.05). Throughout the exercise, fat oxidation was higher in trained than in untrained subjects (p < 0.05). Muscle HSL activity was similar at rest (0.72 ± 0.08 and 0.74 ± 0.03 mU mg−1 protein) and after exercise (0.71 ± 0.1 and 0.68 ± 0.03 mU mg−1 protein) in untrained and trained subjects. At rest, the chemically determined muscle TG content (37 ± 8 and 26 ± 5 mmol g−1 d.w.) was similar (p > 0.05), and after exercise it was unchanged in untrained and lower (p < 0.05) in trained subjects (41 ± 9 and 10 ± 2 mmol g(1 d.w.). Determined histochemically, TG was decreased (p < 0.05) after exercise in type I and II fibres. Depletion of TG was not different between fibre types in untrained, but tended to be higher (p = 0.07) in type I compared with type II fibres in trained muscles. In conclusion, HSL activity is similar in untrained and trained skeletal muscles both before and after prolonged exercise. However, the tendency to higher muscle TG recruitment during exercise in the trained subjects suggests a difference in the regulation of HSL or other lipases during exercise in trained compared with untrained subjects. 相似文献
9.
Katayama K Sato K Matsuo H Ishida K Iwasaki K Miyamura M 《European journal of applied physiology》2004,92(1-2):75-83
The purpose of the present study was to clarify the following: (1) whether steady state oxygen uptake (O2) during exercise decreases after short-term intermittent hypoxia during a resting state in trained athletes and (2) whether the change in O2 during submaximal exercise is correlated to the change in endurance performance after intermittent hypoxia. Fifteen trained male endurance runners volunteered to participate in this study. Each subject was assigned to either a hypoxic group (n=8) or a control group (n=7). The hypoxic group spent 3 h per day for 14 consecutive days in normobaric hypoxia [12.3 (0.2)% inspired oxygen]. The maximal and submaximal exercise tests, a 3,000-m time trial, and resting hematology assessments at sea level were conducted before and after intermittent normobaric hypoxia. The athletes in both groups continued their normal training in normoxia throughout the experiment. O2 during submaximal exercise in the hypoxic group decreased significantly (P<0.05) following intermittent hypoxia. In the hypoxic group, the 3,000-m running time tended to improve (P=0.06) after intermittent hypoxia, but not in the control group. Neither peak O2 nor resting hematological parameters were changed in either group. There were significant (P<0.05) relationships between the change in the 3,000-m running time and the change in O2 during submaximal exercise after intermittent hypoxia. The results from the present study suggest that the enhanced running economy resulting from intermittent hypoxia could, in part, contribute to improved endurance performance in trained athletes. 相似文献
10.
P. Kannus D. Alosa L. Cook R. J. Johnson P. Renström M. Pope B. Beynnon K. Yasuda C. Nichols M. Kaplan 《European journal of applied physiology》1992,64(2):117-126
Summary The purpose of this investigation was to study the effect of one-legged exercise on the strength, power and endurance of the contralateral leg. The performance of the knee extensor and flexor muscle of 20 healthy young adults (10 men and 10 women) was first tested by Cybex II+ and 340 dynamometers. Then 10 subjects were chosen at random to train using one leg three times a week for 7 weeks whilst the other 10 served as controls. During the 8th week, the tests were repeated. Both quadriceps and hamstring muscles of the trained subjects showed a cross-transfer effect from the trained limb to the untrained side. This concerned the strength and power, as well as endurance characteristics of these muscles. The average change in peak torque of the quadriceps muscle was + 19% (P<0.001) in the trained limb, + 11% (P<0.01) in the untrained limb and 0% in the control limbs. In hamstring muscles the changes were + 14% (P<0.01), + 5% and –1%, respectively. Concerning muscle endurance (work performed during the last 5 contractions in the 25-repetition test) the corresponding changes were + 15% (P<0.01), +7% (P<0.01), and –1% in quadriceps muscle, and + 17% (P<0.05), +7%, and –3% in hamstring muscles. The average strength benefit in the untrained limb was +36% (hamstring muscles) and +58% (quadriceps muscle) of that achieved in the trained limb. Untrained hamstring muscle showed better benefits in the endurance parameters than in strength or power parameters, while in the quadriceps muscle this effect was reversed. A positive relationship was observed between the changes (greater improvement in the trained limb resulted in greater improvement in the untrained limb) (hamstring muscles:r=0.83,P<0.001, quadriceps muscle:r=0.53,P<0.001). In endurance parameters, this relationship was almost linear while in the strength and power parameters the results were more in favour of a curvilinear relationship with limited benefit. 相似文献
11.
Scott K. Powers Daniel Martin Michael Cicale Nancy Collop David Huang David Criswell 《European journal of applied physiology》1992,65(1):37-42
Summary These experiments examined the exercise-induced changes in pulmonary gas exchange in elite endurance athletes and tested the hypothesis that an inadequate hyperventilatory response might explain the large intersubject variability in arterial partial pressure of oxygen (P
a02) during heavy exercise in this population. Twelve highly trained endurance cyclists [maximum oxygen consumption (VO2max) range = 65-77 ml·kg–1·min–1] performed a normoxic graded exercise test on a cycle ergometer toVO2max at sea level. During incremental exercise atVO2max 5 of the 12 subjects had ideal alveolar to arterial P02 gradients (P
A-aO2) of above 5 kPa (range 5-5.7) and a decline from restingP
aO2 (P
aO2) 2.4 kPa or above (range 2.4-2.7). In contrast, 4 subjects had a maximal exercise (P
A-aO2) of 4.0-4.3 kPa with P
aO2 of 0.4-1.3 kPa while the remaining 3 subjects hadP
A-aO2 of 4.3-5 kPa with P
aO2 between 1.7 and 2.0 kPa. The correlation between PAO2 andP
aO2 atVO2max was 0.17. Further, the correlation between the ratio of ventilation to oxygen consumption VSP
aO2 and arterial partial pressure of carbon dioxide VSP
aO2 atVO2max was 0.17 and 0.34, respectively. These experiments demonstrate that heavy exercise results in significantly compromised pulmonary gas exchange in approximately 40% of the elite endurance athletes studied. These data do not support the hypothesis that the principal mechanism to explain this gas exchange failure is an inadequate hyperventilatory response. 相似文献
12.
Patrick Mucci Jacques Prioux Maurice Hayot Michèle Ramonatxo Christian Préfaut 《European journal of applied physiology》1998,77(4):343-351
Exercise-induced hypoxaemia (EIH) in master athletes may be related to a diminished exercise hyper- pnoea. The aim of this study was to determine whether EIH is associated with a change in the sensitivity of the ventilation response to activation of the central chemoreceptors. The ventilation response to CO2 was measured in nine elderly untrained men (UT) [mean age 66.3 (SEM 3.1) years] and nine master athletes (MA) [mean age 62.7 (SEM 0.8) years] at rest, during moderate exercise (40% maximal oxygen uptake, V˙O2max), and during strenuous exercise (70% V˙O2max) using the rebreathing method. Our results showed that the ventilation response to CO2 did not differ with endurance training and/or exercise, that the threshold of the CO2 response (Th) increased with exercise (P?0.001), that the increase in Th in MA was higher than in UT between rest and moderate exercise [ΔTh0–40: 8.55 (SEM 1.8) vs 3.06 (SEM 1.72) mmHg, P?0.05], and that ΔTh0–40 and Th during moderate exercise were negatively correlated with arterial O2 saturation during maximal exercise (r?=?0.50, P<0.05). We concluded therefore that exercise-induced hypoxaemia in master athletes may not be due to a lower ventilation response to CO2, but may be partly related to a greater increase in Th during moderate exercise. 相似文献
13.
Comparison of muscle buffer capacity and repeated-sprint ability of untrained, endurance-trained and team-sport athletes 总被引:2,自引:0,他引:2
Edg E J Bishop D Hill-Haas S Dawson B Goodman C 《European journal of applied physiology》2006,96(3):225-234
We measured the muscle buffer capacity (βm) and repeated-sprint ability (RSA) of young females, who were either team-sport
athletes (n=7), endurance trained (n=6) or untrained but physically active (n=8). All subjects performed a graded exercise test to determine
followed 2 days later by a cycle test of RSA (5×6 s, every 30 s). Resting muscle samples (Vastus lateralis) were taken to
determine βm. The team-sport group had a significantly higher βm than either the endurance-trained or the untrained groups
(181±27 vs. 148±11 vs. 122±32 μmol H+ g dm−1 pH−1 respectively; P<0.05). The team-sport group also completed significantly more relative total work (299±27 vs. 263±31 vs. 223±21 J kg−1, respectively; P<0.05) and absolute total work (18.2±1.6 vs. 14.6±2.4 vs. 13.0±1.9 kJ, respectively; P<0.05) than the endurance-trained or untrained groups during the RSA test. The team-sport group also had a greater post-exercise
blood lactate concentration, but not blood pH. There was a significant correlation between βm and RSA (r = 0.67; P<0.05). Our findings show that young females competing in team sports have a larger βm than either endurance-trained or untrained
females. This may be the result of the intermittent, high-intensity activity during training and the match play of team-sport
athletes. The team-sport athletes also had a greater RSA than either the endurance-trained or untrained subjects. The greater
total work by team-sport athletes was predominantly due to a better performance during the early sprints of the repeated-sprint
bout. 相似文献
14.
In cardiac rehabilitation, different endurance exercises such as walking and cycling are often performed. The training intensity
for these modes is determined from a single treadmill or bicycle test by ventilatory threshold (VT). In this study, differences
of VT between walking and cycling and agreement of VT between training modes were assessed in cardiac patients. A total of
46 cardiac rehabilitation patients (mean age 59.5 ± 8.4 years, 45 males) (31 untrained and 15 trained) completed a maximal
exercise test on bicycle and treadmill, with breath-by-breath analysis of oxygen uptake (VO2), carbon dioxide production and expiratory volume. VT was determined by V-slope method. Correlations of VT and VO2peak were calculated between exercise modes. Bland–Altman plots were made for determining VT agreement between modes. VT was significantly
different between walking and cycling in trained patients (P < 0.05), but not in untrained patients (P > 0.05). When untrained and trained patients were compared, VT correlation was lower (r = 0.50) in the former group, as compared to the latter group (r = 0.78). Also, Bland–Altman plots showed smaller limits of agreement for VT in trained (2 SD −1.6 to 7.8 ml/min/kg), as compared
to untrained patients (2 SD −7.0 to 9.6 ml/min/kg). In trained patients, VT correlates well between training methods, but
is highly exercise mode specific. In untrained patients, VT is not exercise mode specific, but the VT has a low correlation
between training modes. This study shows that VT should be assessed by the appropriate exercise model for determining exercise
intensity in cardiac rehabilitation. 相似文献
15.
C. Enea N. Boisseau M. Ottavy J. Mulliez C. Millet I. Ingrand V. Diaz B. Dugué 《European journal of applied physiology》2009,106(3):365-373
The objective of this study was to ascertain the effects of menstrual cycle, oral contraception, and training status on the
exercise-induced changes in circulating DHEA-sulphate and testosterone in young women. Twenty-eight healthy women were assigned
to an untrained group (n = 16) or a trained group (n = 12) depending on their training background. The untrained group was composed of nine oral contraceptive users (OC+) and
seven eumenorrheic women (OC−). The trained group was composed of OC+ subjects only. All the OC+ subjects were taking the
same low-dose oral contraception. Three laboratory sessions were organised in a randomised order: a prolonged exercise test
until exhaustion, a short-term exhaustive exercise test, and a control session. Blood specimens were collected before, during
and after the exercise tests and at the same time of the day during the control session. Basal circulating testosterone was
significantly lower in trained as compared to untrained subjects. In all subjects, the prolonged exhaustive exercise induced
a significant increase in circulating DHEA-s and testosterone. The short-term exercise induced a significant increase in circulating
DHEA-s in untrained eumenorrheic and in trained OC users only. Menstrual phases in OC− did not influence the responses. It
was found that exhaustive physical exercise induced an increase in circulating DHEA-s and testosterone in young women. Oral
contraception may limit short-term exercise-induced changes. 相似文献
16.
Prommer N Ehrmann U Schmidt W Steinacker JM Radermacher P Muth CM 《European journal of applied physiology》2007,101(6):753-759
In diving mammals splenic contraction increases circulating red cell volume, whereas in humans increased haemoglobin concentrations
have been reported. It is unknown, however, whether repetitive apnea diving also comprises an adaptive increase in total red
cell volume as reported in endurance athletes. The first aim of the study therefore was to investigate the effect of repeated
apnea dives on splenic size and putative red cell release in trained apnea divers (n = 10) and control subjects (SCUBA divers performing apneas without long-term apnea training, n = 7). Long-term effects of repetitive apnea diving may elevate the oxygen transport capacity by an adaptive increase in total
haemoglobin mass as reported in endurance athletes. The second goal, therefore, was to compare the trained apnea divers’ and
the control divers’ total haemoglobin mass (tHb-mass) with that of endurance-trained (n = 9) and untrained (n = 10) non-divers. Before and immediately after a series of five dives to a depth of 4 m in a heated pool, spleen volume was
assessed with ultrasound tomography. tHb-mass and plasma volume were measured using the CO-rebreathing method. In the trained
apnea divers, repeated apnea dives resulted in a 25% reduction of spleen size (P < 0.001), whereas no significant effect was observed in the control subjects. While tHb-mass did not differ between trained
apnea divers, untrained SCUBA divers performing apneas and untrained non-divers, it was 30% lower than in endurance-trained
non-divers. We conclude that prolonged apnea training causes marked apnea-induced splenic contraction. In contrast to athletes
in endurance sports, the trained apnea divers did not present with increased total haemoglobin mass and, hence, no increase
in blood oxygen stores.
Nicole Prommer and Ulrich Ehrmann equally contributed to this study. 相似文献
17.
18.
Steven Lewis Ph.D. Paul Thompson Nils Holger Areskog Paul Vodak Marian Marconyak Robert DeBusk Susan Mellen William Haskell 《European journal of applied physiology》1980,44(1):25-34
Summary There has been a controversy over whether the increases in maximal oxygen uptake (
O2 max) and reductions in heart rate at a given submaximal workload after endurance training are limited to exercise with trained limbs or also may be observed during exercise with untrained limbs. In the present study five initially very sedentary young men trained by leg cycling (LT) and five by arm cranking (AT) 30 min per day on 4 days a week for 11 weeks at an intensity 75–80%
O2 max. Before and after training the subjects performed submaximal and maximal arm cranking and leg cycling tests. Leg cycling and arm cranking
O2 max increased 15% and 9% after LT and 12% and 35% after AT, respectively. Heart rate at a given submaximal workload was lower (p<0.05) during trained and untrained limb exercise following LT and AT. However, subjective ratings of perceived exertion (RPE) at a given submaximal workload were lower (p<0.01) only during exercise with trained limbs after LT and AT. In light of previous findings, the present increases in
O2 max and reductions in submaximal exercise heart rate with untrained limbs suggest that the initial fitness of the subjects as well as the intensity, frequency, and duration of training may be important factors in determining the extent to which transfer effects of endurance training can be observed. Although the present data suggest that reductions in RPE after endurance training may be the result of local changes in trained muscles, the possible contribution of central nervous adaptations cannot be excluded.Supported in part by Grant HL 18907 from The National Heart, Lung, and Blood Institute 相似文献
19.
Oztasan N Taysi S Gumustekin K Altinkaynak K Aktas O Timur H Siktar E Keles S Akar S Akcay F Dane S Gul M 《European journal of applied physiology》2004,91(5-6):622-627
The aim of this study was to investigate whether endurance training reduces exercise-induced oxidative stress in erythrocytes. Male rats (n=54) were divided into trained (n=28) and untrained (n=26) groups. Both groups were further divided equally into two groups where the rats were studied at rest and immediately after exhaustive exercise. Endurance training consisted of treadmill running 1.5 h·day–1, 5 days a week for 8 weeks, reaching the speed of 2.1 km·h–1 at the fourth week. For acute exhaustive exercise, graded treadmill running was conducted reaching the speed of 2.1 km·h–1 at the 95th min, 10% uphill, and was continued until exhaustion. Acute exhaustive exercise increased the erythrocyte malondialdehyde level in sedentary but not in trained rats compared with the corresponding sedentary rest and trained rest groups, respectively. While acute exhaustive exercise decreased the erythrocyte superoxide dismutase activity in sedentary rats, it increased the activity of this enzyme in trained rats. On the other hand, acute exhaustive exercise increased the erythrocyte glutathione peroxidase activity in sedentary rats; however, it did not affect this enzyme activity in trained rats. Erythrocyte glutathione peroxidase activity was higher in trained groups compared with untrained sedentary group. Neither acute exhaustive exercise nor treadmill training affected the erythrocyte total glutathione level. Treadmill training increased the endurance time in trained rats compared with sedentary rats. The results of this study suggest that endurance training may be useful to prevent acute exhaustive exercise-induced oxidative stress in erythrocytes by up-regulating some of the antioxidant enzyme activities and may have implications in exercising humans. 相似文献
20.
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