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1.
Effects of strength, endurance and combined training on myosin heavy chain content and fibre-type distribution in humans 总被引:2,自引:0,他引:2
Putman CT Xu X Gillies E MacLean IM Bell GJ 《European journal of applied physiology》2004,92(4-5):376-384
This study investigated the effect of strength training, endurance training, and combined strength plus endurance training on fibre-type transitions, fibre cross-sectional area (CSA) and MHC isoform content of the vastus lateralis muscle. Forty volunteers (24 males and 16 females) were randomly assigned to one of four groups: control (C), endurance training (E), strength training (S), or concurrent strength and endurance training (SE). The S and E groups each trained three times a week for 12 weeks; the SE group performed the same S and E training on alternate days. The development of knee extensor muscle strength was S>SE>E (P<0.05) and has been reported elsewhere. The reduction in knee extensor strength development in SE as compared to S corresponded to a 6% increase in MHCIIa content (P<0.05) in SE at the expense of the faster MHCIId(x) isoform (P<0.05), as determined by electrophoretic analyses; reductions in MHCIId/x content after S or E training were attenuated by comparison. Both S and SE induced three- to fourfold reductions (P<0.05) in the proportion of type IIA/IID(X) hybrid fibres. S also induced fourfold increases in the proportion of type I/IIA hybrid fibres within both genders, and in a population of fibres expressing a type I/IID(X) hybrid phenotype within the male subjects. Type I/IIA hybrid fibres were not detected after SE. Both S and SE training paradigms induced similar increases (16–19%, P<0.05) in the CSA of type IIA fibres. In contrast, the increase in CSA of type I fibres was 2.9-fold greater (P<0.05) in S as compared to SE after 12 weeks. We conclude that the interference of knee extensor strength development in SE versus S was related to greater fast-to-slow fibre-type transitions and attenuated hypertrophy of type I fibres. Data are given as mean (SEM) unless otherwise stated. 相似文献
2.
Elina?Sillanp?? David?E.?Laaksonen Arja?H?kkinen Laura?Karavirta Benjamin?Jensen William?J.?Kraemer Kai?Nyman Keijo?H?kkinen 《European journal of applied physiology》2009,106(2):285-296
In this study adaptations in body composition, physical fitness and metabolic health were examined during 21 weeks of endurance
and/or strength training in 39- to 64-year-old healthy women. Subjects (n = 62) were randomized into endurance training (E), strength training (S), combined strength and endurance training (SE),
or control groups (C). S and E trained 2 and SE 2 + 2 times in a week. Muscle strength and maximal oxygen uptake (VO2max) were measured. Leg extension strength increased 9 ± 8% in S (P < 0.001), 12 ± 8% in SE (P < 0.001) and 3 ± 4% in E (P = 0.036), and isometric bench press 20% only in both S and SE (P < 0.001). VO2max increased 23 ± 18% in E and 16 ± 12% in SE (both P < 0.001). The changes in the total body fat (dual X-ray absorptiometry) did not differ between groups, but significant decreases
were observed in E (−5.9%, P = 0.022) and SE (−4.8%, P = 0.005). Lean mass of the legs increased 2.2–2.9% (P = 0.004–0.010) in S, SE and E. There were no differences between the groups in the changes in blood lipids, blood pressure
or serum glucose and insulin. Total cholesterol and low-density lipoprotein cholesterol decreased and high-density lipoprotein
cholesterol increased in E. Both S and SE showed small decreases in serum fasting insulin. Both endurance and strength training
and their combination led to expected training-specific improvements in physical fitness, without interference in fitness
or muscle mass development. All training methods led to increases in lean body mass, but decreases in body fat and modest
improvements in metabolic risk factors were more evident with aerobic training than strength training. 相似文献
3.
Neuromuscular adaptations during concurrent strength and endurance training versus strength training 总被引:5,自引:0,他引:5
Häkkinen K Alen M Kraemer WJ Gorostiaga E Izquierdo M Rusko H Mikkola J Häkkinen A Valkeinen H Kaarakainen E Romu S Erola V Ahtiainen J Paavolainen L 《European journal of applied physiology》2003,89(1):42-52
The purpose of this study was to investigate effects of concurrent strength and endurance training (SE) (2 plus 2 days a week)
versus strength training only (S) (2 days a week) in men [SE: n=11; 38 (5) years, S: n=16; 37 (5) years] over a training period of 21 weeks. The resistance training program addressed both maximal and explosive
strength components. EMG, maximal isometric force, 1 RM strength, and rate of force development (RFD) of the leg extensors,
muscle cross-sectional area (CSA) of the quadriceps femoris (QF) throughout the lengths of 4/15–12/15 (L
f) of the femur, muscle fibre proportion and areas of types I, IIa, and IIb of the vastus lateralis (VL), and maximal oxygen
uptake (V˙O2max) were evaluated. No changes occurred in strength during the 1-week control period, while after the 21-week training period
increases of 21% (p<0.001) and 22% (p<0.001), and of 22% (p<0.001) and 21% (p<0.001) took place in the 1RM load and maximal isometric force in S and SE, respectively. Increases of 26% (p<0.05) and 29% (p<0.001) occurred in the maximum iEMG of the VL in S and SE, respectively. The CSA of the QF increased throughout the length
of the QF (from 4/15 to 12/15 L
f) both in S (p<0.05–0.001) and SE (p<0.01–0.001). The mean fibre areas of types I, IIa and IIb increased after the training both in S (p<0.05 and 0.01) and SE (p<0.05 and p<0.01). S showed an increase in RFD (p<0.01), while no change occurred in SE. The average iEMG of the VL during the first 500 ms of the rapid isometric action increased
(p<0.05–0.001) only in S. V˙O2max increased by 18.5% (p<0.001) in SE. The present data do not support the concept of the universal nature of the interference effect in strength
development and muscle hypertrophy when strength training is performed concurrently with endurance training, and the training
volume is diluted by a longer period of time with a low frequency of training. However, the present results suggest that even
the low-frequency concurrent strength and endurance training leads to interference in explosive strength development mediated
in part by the limitations of rapid voluntary neural activation of the trained muscles.
Electronic Publication 相似文献
4.
LeMura LM von Duvillard SP Andreacci J Klebez JM Chelland SA Russo J 《European journal of applied physiology》2000,82(5-6):451-458
The purpose of this study was to evaluate the effects of various modes of training on the time-course of changes in lipoprotein-lipid
profiles in the blood, cardiovascular fitness, and body composition after 16 weeks of training and 6 weeks of detraining in
young women. A group of 48 sedentary but healthy women [mean age 20.4 (SD 1) years] were matched and randomly placed into
a control group (CG, n=12), an aerobic training group (ATG, n=12), a resistance training group (RTG, n=12), or a cross-training group that combined both aerobic and resistance training (XTG, n=12). The ATG, RTG and XTG trained for 16 weeks and were monitored for changes in blood concentrations of lipoprotein-lipids,
cardiovascular fitness, body composition, and dietary composition throughout a 16 week period of training and 6 weeks of detraining.
The ATG significantly reduced blood concentrations of triglycerides (TRI) (P < 0.05) and significantly increased blood concentrations of high-density lipoprotein-cholesterol (HDL-C) after 16 weeks of
training. The correlation between percentage fat and HDL-C was 0.63 (P < 0.05), which explained 40% of the variation in HDL-C, while the correlation between maximal oxygen uptake (V˙O2max) and HDL-C was 0.48 (P < 0.05), which explained 23% of the variation in HDL-C. The ATG increased V˙O2max by 25% (P < 0.001) and decreased percentage body fat by 13% (P < 0.05) after 16 weeks. Each of the alterations in the ATG had disappeared after the 6 week detraining period. The concentration
of total cholesterol (TC), TRI, HDL-C and low density lipoprotein-cholesterol in the blood did not change during the study
in RTG, XTG and CG. The RTG increased upper and lower body strength by 29% (P < 0.001) and 38%, respectively. The 6 week detraining strength values obtained in RTG were significantly greater than those
obtained at baseline. The XTG increased upper and lower body strength by 19% (P < 0.01) and 25% (P < 0.001), respectively. The 6 week detraining strength values obtained in XTG were significantly greater than those obtained
at baseline. The RTG, XTG and CG did not demonstrate any significant changes in either V˙O2max, or body composition during the training and detraining periods. The results of this study suggest that aerobic-type exercise
improves lipoprotein-lipid profiles, cardiorespiratory fitness and body composition in healthy, young women, while resistance
training significantly improved upper and lower body strength only.
Accepted: 9 April 2000 相似文献
5.
Nygren AT Sundberg CJ Göransson H Esbjörnsson-Liljedahl M Jansson E Kaijser L 《European journal of applied physiology》2000,82(1-2):137-141
The effect of training under conditions of local leg ischaemia on muscle area and fibre dimensions was studied in nine males.
Leg ischaemia was induced by enclosing the legs in a pressure chamber and sealing the opening with a rubber membrane at the
level of the crotch. Air pressure over the legs was 50 mmHg. The subjects performed 16 sessions (45 min) of one-legged supine
strenuous ischaemic training during 4 weeks. Exercise intensity was maintained as high as possible during the whole session.
The contralateral leg served as a control leg and remained passive during exercise. Before and after the training period,
muscle fibre dimensions were determined from biopsy samples taken from the m. vastus lateralis, and leg muscle dimensions
were assessed by magnetic resonance imaging (MRI). In the trained leg, mean fibre area increased by 12% (P < 0.05). The MRI-assessed cross-sectional area of the vastus group increased by 4% (P=0.01). In the control leg, mean fibre area and the cross-sectional area of the vastus group were unchanged, while those of
the adductor muscle group decreased by 4% (P < 0.05). It is concluded that a short period of strenuous ischaemic endurance training increases the cross-sectional area
of the ischaemically trained muscle group, as measured both by MRI and from muscle biopsy samples. In contrast, the adductor
muscles in the contralateral thigh showed a decreased cross-sectional area (as assessed by MRI), possibly due to the effects
of the strenuous contralateral training, by mechanisms that have yet to be identified.
Accepted: 26 December 1999 相似文献
6.
The effects of replacing a portion of endurance training by explosive strength training on performance in trained cyclists 总被引:1,自引:0,他引:1
Bastiaans JJ van Diemen AB Veneberg T Jeukendrup AE 《European journal of applied physiology》2001,86(1):79-84
To investigate the effects of replacing a portion of endurance training by strength training on exercise performance, 14
competitive cyclists were divided into an experimental (E; n=6) and a control (C; n=8) group. Both groups received a training program of 9 weeks. The total training volume for both groups was the same [E:
8.8 (1.1) h/week; C: 8.9 (1.7) h/week], but 37% of training for E consisted of explosive-type strength training, whilst C
received endurance training only. Simulated time trial performance (TT), short-term performance (STP), maximal workload (
) and gross (GE) and delta efficiency (DE) were measured before, after 4 weeks and at the end of the training program (9 weeks).
No significant group-by-training effects for the markers of endurance performance (TT and
) were found after 9 weeks, although after 4 weeks, these markers had only increased (P<0.05) in E. STP decreased (P<0.05) in C, whereas no changes were observed in E. For DE, a significant group-by-training interaction (P<0.05) was found, and for GE the group-by-training interaction was not significant. It is concluded that replacing a portion
of endurance training by explosive strength training prevents a decrease in STP without compromising gains in endurance performance
of trained cyclists.
Electronic Publication 相似文献
7.
Neuromuscular adaptation during prolonged strength training, detraining and re-strength-training in middle-aged and elderly people 总被引:6,自引:0,他引:6
Häkkinen K Alen M Kallinen M Newton RU Kraemer WJ 《European journal of applied physiology》2000,83(1):51-62
Effects of a 24-week strength training performed twice weekly (24 ST) (combined with explosive exercises) followed by either
a 3-week detraining (3 DT) and a 21-week re-strength-training (21 RST) (experiment A) or by a 24-week detraining (24 DT) (experiment
B) on neural activation of the agonist and antagonist leg extensors, muscle cross-sectional area (CSA) of the quadriceps femoris,
maximal isometric and one repetition maximum (1-RM) strength and jumping (J) and walking (W) performances were examined. A
group of middle-aged (M, 37–44 years, n=12) and elderly (E, 62–77, n=10) and another group of M (35–45, n=7) and E (63–78, n=7) served as subjects. In experiment A, the 1-RM increased substantially during 24 ST in M (27%, P < 0.001) and E (29%, P < 0.001) and in experiment B in M (29%, P < 0.001) and E (23%, P < 0.01). During 21 RST the 1-RM was increased by 5% at week 48 (P < 0.01) in M and 3% at week 41 in E (n.s., but P < 0.05 at week 34). In experiment A the integrated electromyogram (IEMG) of the vastus muscles in the 1-RM increased during
24 ST in both M (P < 0.05) and E (P < 0.001) and during 21 RST in M for the right (P < 0.05) and in E for both legs (P < 0.05). The biceps femoris co-activation during the 1-RM leg extension decreased during the first 8-week training in M (from
29 ± 5% to 25 ± 3%, n.s.) and especially in E (from 41 ± 11% to 32 ± 9%, P < 0.05). The CSA increased by 7% in M (P < 0.05) and by 7% in E (P < 0.001), and by 7% (n.s.) in M and by 3% in E (n.s.) during 24 ST periods. Increases of 18% (P < 0.001) and 12% (P < 0.05) in M and 22% (P < 0.001) and 26% (P < 0.05) in E occurred in J. W speed increased (P < 0.05) in both age groups. The only decrease during 3 DT was in maximal isometric force in M by 6% (P < 0.05) and by 4% (n.s.) in E. During 24 DT the CSA decreased in both age groups (P < 0.01), the 1-RM decreased by 6% (P < 0.05) in M and by 4% (P < 0.05) in E and isometric force by 12% (P < 0.001) in M and by 9% (P < 0.05) in E, respectively, while J and W remained unaltered. The strength gains were accompanied by increased maximal voluntary
neural activation of the agonists in both age groups with reduced antagonist co-activation in the elderly during the initial
training phases. Neural adaptation seemed to play a greater role than muscle hypertrophy. Short-term detraining led to only
minor changes, while prolonged detraining resulted in muscle atrophy and decreased voluntary strength, but explosive jumping
and walking actions in both age groups appeared to remain elevated for quite a long time by compensatory types of physical
activities when performed on a regular basis.
Accepted: 2 May 2000 相似文献
8.
Izquierdo M Häkkinen K Ibáñez J Kraemer WJ Gorostiaga EM 《European journal of applied physiology》2005,94(1-2):70-75
The effects of a 16-week training period (2 days per week) of resistance training alone (upper- and lower-body extremity exercises) (S), endurance training alone (cycling exercise) (E), or combined resistance (once weekly) and endurance (once weekly) training (SE) on muscle mass, maximal strength (1RM) and power of the leg and arm extensor muscles, maximal workload (Wmax) and submaximal blood lactate accumulation by using an incremental cycling test were examined in middle-aged men [S, n=11, 43 (2) years; E, n=10, 42 (2) years; SE, n=10, 41 (3) years]. During the early phase of training (from week 0 to week 8), the increase 1RM leg strength was similar in both S (22%) and SE (24%) groups, while the increase at week 16 in S (45%) was larger (P<0.05) than that recorded in SE (37%). During the 16-week training period, the increases in power of the leg extensors at 30% and 45% of 1RM were similar in all groups tested. However, the increases in leg power at the loads of 60% and 70% of 1RM at week 16 in S and SE were larger (P<0.05) than those recorded in E, and the increase in power of the arm extensors was larger (P<0.05) in S than in SE (P<0.05) and E (n.s.). No significant differences were observed in the magnitude of the increases in Wmax between E (14%), SE (12%) and E (10%) during the 16-week training period. During the last 8 weeks of training, the increases in Wmax in E and SE were greater (P<0.05–0.01) than that observed in S (n.s.). No significant differences between the groups were observed in the training-induced changes in submaximal blood lactate accumulation. Significant decreases (P<0.05–0.01) in average heart rate were observed after 16 weeks of training in 150 W and 180 W in SE and E, whereas no changes were recorded in S. The data indicate that low-frequency combined training of the leg extensors in previously untrained middle-aged men results in a lower maximal leg strength development only after prolonged training, but does not necessarily affect the development of leg muscle power and cardiovascular fitness recorded in the cycling test when compared with either mode of training alone. 相似文献
9.
Cardiovascular and muscular adaptations to combined endurance and strength training in elderly women
Twenty-one women aged 60–75 years were examined to determine whether combined endurance and strength training resulted in greater increase in peak oxygen consumption, sub-maximal time to fatigue, cardiac output, stroke volume, and leg extension load when compared to endurance training alone. Subjects in both the endurance training (E) and endurance and strength (E & S) groups trained 3 days a week, for 12 weeks, at an intensity of 70–80% V˙O 2 peak for 30 min on a cycle ergometer. Subjects in the E & S groups also used resistance equipment to train the knee extensors. The workload for resistance training was based on an initial assessment of 10 repetitions maximum (10 RM), with 80% of that value used for training, three times weekly. Peak oxygen consumption increased to an average of 24.8 and 29.9% in the E and E & S groups, respectively, with no difference between groups. Subjects in the E & S and E groups significantly increased sub-maximal endurance time by 396 and 165%, respectively. Cardiac output, stroke volume, and arteriovenous oxygen difference at 80% peak V˙O 2 were unchanged by either of the training methods. A needle biopsy was taken from the vastus lateralis before and after 12 weeks of training. Chi-square analysis of fibre area data showed an increase in the frequency of larger type I fibres in the post-training data from the E & S group, but an increase in the frequency of smaller fibres in the E group post-training; however, mean fibre area was not significantly changed by training. These data suggest that greater improvements in sub-maximal time to fatigue and strength is achieved when resistance training is added to an aerobic training programme in healthy elderly women. 相似文献
10.
Cytochrome c oxidase (CCO) is an enzyme complex found on the inner mitochondrial membrane and serves as the final electron acceptor in
mitochondrial electron transport. Heat shock proteins (HSPs) are involved in the import of nuclear encoded protein subunits
into the mitochondria and induce conformational changes to form active enzyme complexes. As both the nuclear and mitochondrial
encoded subunits of CCO have been shown to increase in activity and expression in muscle subsequent to artificial loading,
and as exercise has been shown to induce HSPs, we sought to determine whether 16–20 weeks of treadmill exercise would result
in enhanced CCO subunit expression, and to determine if there was a relationship between this expression and HSP content in
medial gastrocnemius muscle of Fischer 344 rats. Our results indicated that endurance training resulted in a 53%, 87% and
80% increase (P < 0.05) in the levels of HSP 60, CCO subunit II and CCO subunit VI, respectively. Enzymatic activity of CCO was 84% greater
(P < 0.05) after endurance training. Mann Whitney U analyses showed that CCO subunit II and VI increased to the same extent as HSP 60 after endurance training. It appears that
16–20 weeks of endurance training leads to uniform increases in CCO subunits and parts of the transport and assembly mechanisms
required for CCO enzyme assembly. The similarity among the increases in CCO subunits II and VI protein levels and the increase
in CCO enzyme activity suggest that this increase in activity is due to an increase in the amount of CCO enzyme.
Accepted: 26 April 2000 相似文献
11.
Esteban M. Gorostiaga Mikel Izquierdo Pilar Iturralde Maite Ruesta Javier Ibáñez 《European journal of applied physiology》1999,80(5):485-493
To determine the effects of 6-weeks of heavy-resistance training on physical fitness and serum hormone status in adolescents
(range 14–16 years old) 19 male handball players were divided into two different groups: a handball training group (NST, n = 10), and a handball and heavy-resistance strength training group (ST, n = 9). A third group of 4 handball goalkeepers of similar age served as a control group (C, n = 4). After the 6-week training period, the ST group showed an improvement in maximal dynamic strength of the leg extensors
(12.2%; P < 0.01) and the upper extremity muscles (23%; P < 0.01), while no changes were observed in the NST and C groups. Similar differences were observed in the maximal isometric
unilateral leg extension forces. The height of the vertical jump increased in the NST group from 29.5 (SD 4) cm to 31.4 (SD
5) cm (P < 0.05) while no changes were observed in the ST and C groups. A significant increase was observed in the ST group in the
velocity of the throwing test [from 71.7 (SD 7) km · h−1 to 74.0 (SD 7) km · h−1; P < 0.001] during the 6-week period while no changes were observed in the NST and C groups. During a submaximal endurance test
running at 11 km · h−1, a significant decrease in blood lactate concentration occurred in the NST group [from 3.3 (SD 0.9) mmol · l−1 to 2.4 (SD 0.8) mmol · l−1; P < 0.01] during the experiment, while no change was observed in the ST or C groups. Finally, a significant increase (P < 0.01) was noted in the testosterone:cortisol ratio in the C group, while the increase in the NST group approached statistical
significance (P < 0.08) and no changes in this ratio occurred in the ST group. The present findings suggested that the addition of 6-weeks
of heavy resistance training to the handball training resulted in gains in maximal strength and throwing velocity but it compromised
gains in leg explosive force production and endurance running. The tendency for a compromised testosterone:cortisol ratio
observed in the ST group could have been associated with a state of overreaching or overtraining.
Accepted: 22 April 1999 相似文献
12.
The effects of strength training with partial tourniquet ischaemia on skeletal muscle capillarity were examined, particularly
in terms of the distribution of arteriolar and venular capillaries and their capillary domain area, in male Wistar rats. A
tourniquet applied around the knee joint induced partial ischaemia. Repeated isometric contractions of calf muscles, 1 s on/1 s
off for 3 min, induced by electrical stimulation (100 Hz), were conducted 2 days/week for 6 weeks as training. Morphologic
data were obtained from four groups; non-treatment control (C), ischaemic (IS), non-ischaemic training (NIT) and ischaemic
training (IT). In the superficial portion of gastrocnemius (GASs) muscle, the total capillary density of arteriolar capillaries
was significantly greater in the IT-leg than in the C-leg (P < 0.05). In the plantaris (PL) muscle, these values were significantly greater in the IT-leg than in both the C- and NIT-legs
(P < 0.05). Only in the GASs was the capillary-to-fibre ratio significantly greater in the IT-leg than in the C-leg (P < 0.05). In GASs and PL, the capillary domain area (CDA) was smaller in the IT-leg than in the C- and NIT-legs. In all muscles
examined, mean fibre cross-sectional area was not significantly changed by the experimental treatment. These findings suggest
that adaptive changes in the microvascular network, identified as an increase in the arteriolar capillary area and a reduction
in diffusion distance, occur in the skeletal muscles after strength training with partial ischaemia. These adaptive changes
probably improve the supply of oxygen and nutrients to skeletal muscle tissues.
Accepted: 22 February 2000 相似文献
13.
J. L. Mauriz B. Tabernero J. García-López F. Jorquera J. G. Villa J. González-Gallego 《European journal of applied physiology》2000,81(1-2):62-66
Drug metabolizing capacity is generally reduced in the elderly, and physical exercise has been reported to increase drug
oxidative metabolism. The purpose of this investigation was to study the effects of engagement in a program of regular physical
exercise on the clearance and metabolite excretion of antipyrine, a marker of oxidative metabolism, in elderly subjects. The
saliva clearance of antipyrine and the production clearances of antipyrine metabolites were studied in 37 elderly women (mean
age 66 years). Subjects attended 60-min sessions three times a week for 12 weeks. Each session consisted of both aerobic (training
of cardiorespiratory capacity) and nonaerobic (training of muscular strength/endurance and flexibility/coordination) exercises
performed at 50–75% of maximum oxygen uptake. Antipyrine was administered orally and pharmacokinetic parameters were obtained
from saliva and urine samples. After 3 months of participation in the exercise program, salivary antipyrine clearance was
significantly increased by 17% mean (SEM) 0.42 (0.02) vs 0.36 (0.02) ml/min/kg; P < 0.05) and the half-life of antipyrine was significantly reduced by 18% (17.9 (1.1) vs 22.3 (1.3) h; P < 0.05). No significant change with exercise was observed in the renal clearance of antipyrine or in the norantipyrine formation
clearance, but significant increases were found for hydroxymethylantipyrine [42 (5) vs 32 (4) μl/kg/min; P < 0.05; +31%] and 4-hydroxyantipyrine [243 (18) vs 194 (17) μl/kg/min; P < 0.05; +25%] formation clearances. These findings indicate that regular exercise leads to increased disposition of antipyrine
in the elderly and that the main metabolic pathways of the compound are changed differentially.
Accepted: 25 June 1999 相似文献
14.
M: Shinohara Motoki Kouzaki Takeshi Yoshihisa Tetsuo Fukunaga 《European journal of applied physiology》1997,77(1-2):189-191
To investigate the efficacy of ischemia in strength training with low mechanical stress, tourniquet ischemia was utilized
in low-resistance training. Five untrained subjects conducted one-legged isometric knee extension training with one leg ischemic
(I-leg) and the other non-ischemic (NI-leg). Repeated isometric contractions for 2 s with 3 s relaxation in between were continued
for 3 min and conducted 3 days/week for 4 weeks as training. Training resistance was 40% of maximal voluntary contraction
(MVC) of respective leg and tourniquet ischemia was applied during I-leg training. MVC in I-leg after 2 weeks (9% gain) and
4 weeks (26% gain) were significantly higher than pre-training value (p < 0.05). A significant increase in maximal rate of torque development in I-leg was observed after 4 weeks (p < 0.05). On the contrary, there was no significant changes in either of the parameters in NI-leg. As a consequence, the differences
between legs for both parameters were significant after 2 and 4 weeks (p < 0.05 or p < 0.01). The substantial gain in strength and maximal rate of torque development in I-leg demonstrated the efficacy of tourniquet
ischemia during low-resistance training of short duration, and suggested the importance of neuromuscular and/or metabolic
activity, other than high mechanical stress, to the adapting responses to strength training.
Accepted: 17 July 1997 相似文献
15.
Plasma catecholamine responses and neural adaptation during short-term resistance training 总被引:1,自引:0,他引:1
Low exercise-induced plasma adrenaline (A) responses have been reported in resistance-trained individuals. In the study reported
here, we investigated the interaction between strength gain and neural adaptation of the muscles, and the plasma A response
in eight healthy men during a short-term resistance-training period. The subjects performed 5 resistance exercises (E1–E5),
consisting of 6 sets of 12 bilateral leg extensions performed at a 50% load, and with 2 days rest in between. Average electromyographic
(EMG) signal amplitude was recorded before and after the exercises, from the knee extensor muscles in isometric maximal voluntary
contraction (MVC) as well as during the exercises (aEMGmax and aEMGexerc, respectively). Total oxygen consumed during the exercises (V˙O2tot) was also measured. All of the exercises were exhaustive and caused significant decreases in MVC (34–36%, P < 0.001). As expected, the concentric one-repetition maximum (1-RM), MVC and aEMGmax were all higher before the last exercise (E5) than before the first exercise (E1; 7, 9 and 19%, respectively, P < 0.05). In addition, in E5 the aEMGexerc:load and V˙O2tot:load ratios were lower than in E1 (−5 and −14%, P < 0.05), indicating enhanced efficiency of the muscle contractions, However, the post-exercise plasma noradrenaline (NA)
and A were not different in these two exercises [mean (SD) 10.2 (3.8) nmol · l−1 vs 11.3 (6.0) nmol · l−1, ns, and 1.2 (1.0) nmol · l−1 vs 1.9 (1.1) nmol · l−1, ns, respectively]. However, although NA increased similarly in every exercise (P < 0.01), the increase in A reached the level of statistical significance only in E1 (P < 0.05). The post-exercise A was also already lower in E2 [0.7 (0.7) nmol · l−1, P < 0.05) than in E1, despite the higher post-exercise blood lactate concentration than in the other exercises [9.4 (1.1) mmol · l−1, P < 0.05]. Thus, the results suggest that the observed attenuation in the A response can not be explained by reduced exercise-induced
strain due to the strength gain and neural adaptation of the muscles. Correlation analysis actually revealed that those individuals
who had the highest strength gain during the training period even tended to have an increased post-exercise A concentration
in the last exercise as compared to first one (r=0.76, P < 0.05).
Accepted: 10 February 2000 相似文献
16.
Heather K. Vincent Scott K. Powers Darby J. Stewart Haydar A. Demirel R. Andrew Shanely Hisashi Naito 《European journal of applied physiology》2000,81(1-2):67-74
These experiments tested the hypothesis that short-term endurance exercise training would rapidly improve (within 5 days)
the diaphragm oxidative/antioxidant capacity and protect the diaphragm against contraction-induced oxidative stress. To test
this postulate, male Sprague-Dawley rats (6 weeks old) ran on a motorized treadmill for 5 consecutive days (40–60 min · day−1) at approximately 65% maximal oxygen uptake. Costal diaphragm strips were excised from both sedentary control (CON, n=14) and trained (TR, n=13) animals 24 h after the last exercise session, for measurement of in vitro contraction properties and selected biochemical
parameters of oxidative/antioxidant capacity. Training did not alter diaphragm force-frequency characteristics over a full
range of submaximal and maximal stimulation frequencies (P > 0.05). In contrast, training improved diaphragm resistance to fatigue as contraction forces were better-maintained by the
diaphragms of the TR animals during a submaximal 60-min fatigue protocol (P < 0.05). Following the fatigue protocol, diaphragm strips from the TR animals contained 30% lower concentrations of lipid
hydroperoxides compared to CON (P < 0.05). Biochemical analysis revealed that exercise training increased diaphragm oxidative and antioxidant capacity (citrate
synthase activity +18%, catalase activity +24%, total superoxide dismutase activity +20%, glutathione concentration +10%)
(P < 0.05). These data indicate that short-term exercise training can rapidly elevate oxidative capacity as well as enzymatic
and non-enzymatic antioxidant defenses in the diaphragm. Furthermore, this up-regulation in antioxidant defenses would be
accompanied by a reduction in contraction-induced lipid peroxidation and an increased fatigue resistance.
Accepted: 6 August 1999 相似文献
17.
Strenuous endurance training in humans reduces oxidative stress following exhausting exercise 总被引:12,自引:0,他引:12
Miyazaki H Oh-ishi S Ookawara T Kizaki T Toshinai K Ha S Haga S Ji LL Ohno H 《European journal of applied physiology》2001,84(1-2):1-6
The aim of this study was to evaluate whether high-intensity endurance training would alleviate exercise-induced oxidative
stress. Nine untrained male subjects (aged 19–21 years) participated in a 12-week training programme, and performed an acute
period of exhausting exercise on a cycle ergometer before and after training. The training programme consisted of running
at 80% maximal exercise heart rate for 60 min · day−1, 5 days · week−1 for 12 weeks. Blood samples were collected at rest and immediately after exhausting exercise for measurements of indices
of oxidative stress, and antioxidant enzyme activities [superoxide dismutase (SOD), glutathione peroxidase (GPX), and catalase
(CAT)] in the erythrocytes. Maximal oxygen uptake (V˙O2max) increased significantly (P < 0.001) after training, indicating an improvement in aerobic capacity. A period of exhausting exercise caused an increase
(P < 0.01) in the ability to produce neutrophil superoxide anion (O2
•−) both before and after endurance training, but the magnitude of the increase was smaller after training (P < 0.05). There was a significant increase in lipid peroxidation in the erythrocyte membrane, but not in oxidative protein,
after exhausting exercise, however training attenuated this effect. At rest, SOD and GPX activities were increased after training.
However, there was no evidence that exhausting exercise enhanced the levels of any antioxidant enzyme activity. The CAT activity
was unchanged either by training or by exhausting exercise. These results indicate that high-intensity endurance training
can elevate antioxidant enzyme activities in erythrocytes, and decrease neutrophil O2
•− production in response to exhausting exercise. Furthermore, this up-regulation in antioxidant defences was accompanied by
a reduction in exercise-induced lipid peroxidation in erythrocyte membrane.
Accepted: 26 September 2000 相似文献
18.
Medbø JI Jebens E Vikne H Refsnes PE Gramvik P 《European journal of applied physiology》2001,84(1-2):148-154
This study examined how strenuous strength training affected the Na-K pump concentration in the knee extensor muscle of well-trained
men and whether leg muscle strength and endurance was related to the pump concentration. First, the pump concentration, taken
as 3H-ouabain binding, was measured in top alpine skiers since strength training is important to them. Second, well-trained subjects
carried out strenuous eccentric resistance training either 1, 2, or 3 times · week−1 for 3 months. The Na-K pump concentration, the maximal muscle strength in a full squat lift (one repetition maximum, 1 RM),
and the muscle endurance, taken as the number of full squat lifts of a mass of 70% of the 1 RM load, were measured before
and after the training period. The mean pump concentration of the alpine skiers was 425 (SEM 11) nmol · kg−1 wet muscle mass. The subjects in part two increased their maximal strength in a dose-dependent manner. The muscle endurance
increased for all subjects but independently of the training programme. From a mean starting value of 356 (SEM 6) nmol · kg−1 the mean Na-K pump concentration increased by 54 (SEM 15) nmol · kg−1 (+15%, P < 0.001) when the results for all subjects were pooled. The effect was larger for those who had trained twice a week than for
those who had trained only once a week (P=0.025), suggesting that the effect of strength training depended on the amount of training carried out. The muscle strength
and endurance were not related to the pump concentration, suggesting that the pumping power of this enzyme did not limit the
performance during heavy lifting. However, the individual improvements in the endurance test during the training period correlated
with the individual changes in the pump concentration (r
Spearman=0.5; P=0.01) which could mean that a common factor both increases the pump concentration and makes the muscles more adapted to repeated
heavy lifting.
Accepted: 8 August 2000 相似文献
19.
Adiponectin is an anti-inflammatory protein that reduced in obesity. Exercise training may reduce the adipose tissue (AT),
although it is not well known whether exercise-induced change in AT, increases the adiponectin mRNA expression and plasma
concentrations or not; therefore, the purpose of this study was to investigate the adiponectin mRNA and plasma concentrations
in middle-aged men after 12 weeks high-intensity exercise training and after a week detraining. Sixteen sedentary overweight
and obese middle-aged men (age 41.18 ± 6.1 years; ± SD) volunteered to participate in this study. The subjects were randomly
assigned to training group (n = 8) or control group (n = 8). The training group performed endurance training 4 days a week for 12 weeks at an intensity corresponding to 75–80%
individual maximum oxygen consumption for 45 min. After 12 weeks of training, subjects underwent a week of detraining. The
results showed that the BMI as well as central and peripheral AT volume were decreased in the training group compared to the
control group (P < 0.05). After 12 weeks, the training group resulted in a significant increase (P < 0.05) in the adiponectin gene expression in abdominal and gluteal subcutaneous AT when compared with the control group.
The results showed that plasma adiponectin concentrations increased and insulin resistance decreased after training compared
to the control group (P < 0.05). After a week of detraining, the variables were not changed significantly in the training group. In conclusion, high-intensity
endurance training caused an increase adiponectin mRNA in obese middle-aged men. 相似文献
20.
The aim of this study was to observe scutellarin parenteral solution’s therapeutic effects and mechanisms in rats with severe
acute pancreatitis (SAP). We divided SD rats into four groups randomly: (1) sham-operated group, (2) model control group,
(3) scutellarin-treated group, and (4) Salvia miltiorrhiza-treated group. All of those rats in the abovementioned groups are randomly subdivided into 6 and 12 h subgroups, respectively,
according to the postoperative time. Rats have been mercifully killed at different time after operation, and then detected
their serum amylase, contents of ALT, AST, BUN, and Cr and observed the pathologic changes of multiple organs (pancreas, liver,
kidneys, and lungs). We found that the survival rates have no marked differences (P < 0.05) between model control group and two treated groups at any time points. AST and BUN serum contents have no marked
difference (P > 0.05). ALT serum contents in S. miltiorrhiza-treated group (6 and 12 h) and scutellarin-treated group (12 h) are obviously less than those in model control group (P < 0.05). The serum contents of Cr and amylase in scutellarin-treated group (6 h) are obviously less than those in model control
group (P < 0.05). There is a different degree of relief on the pathologic changes of multiple organs in the two treated groups compared
with those in model control group, of which pancreas and liver’s pathologic severity scores in scutellarin-treated group (6
and 12 h) have reduced (P < 0.01) significantly compared with those in the model control group. However, there are no significant differences between
scutellarin-treated group and S. miltiorrhiza-treated group (P > 0.05). We think the scutellarin parenteral solution has a certain protective effect on SAP rats’ multiple organ injuries. 相似文献