共查询到20条相似文献,搜索用时 15 毫秒
1.
Erwin Koninckx Marc Van Leemputte Peter Hespel 《European journal of applied physiology》2010,109(4):699-708
The aim of this study was to compare the effects of a weight training program for the leg extensors with isokinetic cycling
training (80 rpm) on maximal power output and endurance performance. Both strength training interventions were incorporated
twice a week in a similar endurance training program of 12 weeks. Eighteen trained male cyclists (VO2peak 60 ± 1 ml kg−1 min−1) were grouped into the weight training (WT n = 9) or the isokinetic training group (IT n = 9) matched for training background and sprint power (P
max), assessed from five maximal sprints (5 s) on an isokinetic bicycle ergometer at cadences between 40 and 120 rpm. Crank torque
was measured (1 kHz) to determine the torque distribution during pedaling. Endurance performance was evaluated by measuring
power, heart rate and lactate during a graded exercise test to exhaustion and a 30-min performance test. All tests were performed
on subjects’ individual race bicycle. Knee extension torque was evaluated isometrically at 115° knee angle and dynamically
at 200° s−1 using an isokinetic dynamometer. P
max at 40 rpm increased in both the groups (~15%; P < 0.05). At 120 rpm, no improvement of P
max was found in the IT training group, which was possibly related to an observed change in crank torque at high cadences (P < 0.05). Both groups improved their power output in the 30-min performance test (P < 0.05). Isometric knee extension torque increased only in WT (P < 0.05). In conclusion, at low cadences, P
max improved in both training groups. However, in the IT training group, a disturbed pedaling technique compromises an improvement
of P
max at high cadences. 相似文献
2.
Marius S. Fimland Jan Helgerud Gerd Marie Solstad Vegard Moe Iversen Gunnar Leivseth Jan Hoff 《European journal of applied physiology》2009,107(6):723-730
The purpose of this study was to investigate the effects of 4-week (16 sessions) unilateral, maximal isometric strength training
on contralateral neural adaptations. Subjects were randomised to a strength training group (TG, n = 15) or to a control group (CG, n = 11). Both legs of both groups were tested for plantar flexion maximum voluntary isometric contractions (MVCs), surface
electromyogram (EMG), H-reflexes and V-waves in the soleus (SOL) and gastrocnemius medialis (GM) superimposed during MVC and
normalised by the M-wave (EMG/MSUP, HSUP/MSUP, V/MSUP, respectively), before and after the training period. For the untrained leg, the TG increased compared to the CG for MVC
torque (33%, P < 0.01), SOL EMG/MSUP (32%, P < 0.05) and SOL V/MSUP (24%, P < 0.05). For the trained leg, the TG increased compared to the CG for MVC torque (40%, P < 0.01), EMG/MSUP (SOL: 38%, P < 0.05; GM: 60%, P < 0.05) and SOL V/MSUP (72%, P < 0.01). HSUP/MSUP remained unchanged for both limbs. No changes occurred in the CG. These results reinforce the concept that enhanced neural
drive to the contralateral agonist muscles contributes to cross-education of strength. 相似文献
3.
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
4.
The aim was to study whether whole body vibration (WBV) combined with conventional resistance training (CRT) induces a higher
increase in neuromuscular and hormonal measures compared with CRT or WBV, respectively. Twenty-eight young men were randomized
in three groups; squat only (S), combination of WBV and squat (S+V) and WBV only (V). S+V performed six sets with eight repetitions
with corresponding eight repetition maximum (RM) loads on the vibrating platform, whereas S and V performed the same protocol
without WBV and resistance, respectively. Maximal isometric voluntary contraction (MVC) with electromyography (EMG) measurements
during leg press, counter movement jump (CMJ) measures (mechanical performance) including jump height, mean power (P
mean), peak power (P
peak) and velocity at P
peak (V
ppeak) and acute hormonal responses to training sessions were measured before and after a 9-week training period. ANOVA showed
no significant changes between the three groups after training in any neuromuscular variable measured [except P
mean, S higher than V (P<0.05)]. However, applying t tests within each group revealed that MVC increased in S and S+V after training (P<0.05). Jump height, P
mean and P
peak increased only in S, concomitantly with increased V
ppeak in all groups (P<0.05). Testosterone increased during training sessions in S and S+V (P<0.05). Growth hormone (GH) increased in all groups but S+V showed higher responses than S and V (P<0.05). Cortisol increased only in S+V (P<0.05). We conclude that combined WBV and CRT did not additionally increase MVC and mechanical performance compared with CRT
alone. Furthermore, WBV alone did not increase MVC and mechanical performance in spite of increased GH. 相似文献
5.
Robert M. Erskine David A. Jones Alun G. Williams Claire E. Stewart Hans Degens 《European journal of applied physiology》2010,110(6):1117-1125
Considerable variation exists between people in the muscle response to resistance training, but there are numerous ways muscle
might adapt to overload that might explain this variable response. Therefore, the aim of this study was to quantify the range
of responses concerning the training-induced change in maximum voluntary contraction (MVC) knee joint torque, quadriceps femoris
(QF) maximum muscle force (F), physiological cross-sectional area (PCSA) and specific tension (F/PCSA). It was hypothesized that the variable change in QF specific tension between individuals would be less than that of
MVC. Fifty-three untrained young men performed progressive leg-extension training three times a week for 9 weeks. F was determined from MVC torque, voluntary muscle activation level, antagonist muscle co-activation and patellar tendon moment
arm. QF specific tension was established by dividing F by QF PCSA, which was calculated from the ratio of QF muscle volume to muscle fascicle length. MVC torque increased by 26 ± 11%
(P < 0.0001; range −1 to 52%), while F increased by 22 ± 11% (P < 0.0001; range −1 to 44%). PCSA increased by 6 ± 4% (P < 0.001; range −3 to 18%) and specific tension increased by 17 ± 11% (P < 0.0001; range −5 to 39%). In conclusion, training-induced changes in F and PCSA varied substantially between individuals, giving rise to greater inter-individual variability in the specific tension
response compared to that of MVC. Furthermore, it appears that the change in specific tension is responsible for the variable
change in MVC. 相似文献
6.
Aim: This study determined changes in knee extensor and plantar flexor muscle volume during 29 days of bed rest with or without resistance exercise using a gravity‐independent flywheel ergometer. Methods: Seventeen men (26–41 years) were subjected to 29 days of bed rest with (n = 8) or without (n = 9) resistance exercise; Supine Squat (SS) and Calf Press (CP) performed every third day. Quadriceps and triceps surae muscle volume was determined before and after bed rest and force and power were measured during training. Prior to these interventions, reproducibility of this device for training and testing was assessed in 23 subjects who performed bilateral maximal concentric, eccentric and isometric (MVC) knee extensions and plantar flexions over repeated sessions with simultaneous measurements of force, power and electromyographic (EMG) activity. Results: Quadriceps and triceps surae muscle volume decreased (P < 0.05) 10 and 16%, respectively, after 29 days bed rest. Exercise maintained quadriceps volume and mitigated triceps surae atrophy. Thus, either muscle showed different response across subject groups (P < 0.05). Force and power output during training were either maintained (P > 0.05) or increased (P < 0.05). EMG amplitude in the training mode was similar (SS; P > 0.05) or greater (CP; P < 0.05) compared with that elicited during MVC. Peak force and power test‐retest coefficient of variation (CV) ranged 5–6% and 7–8% for SS and CP, respectively. Conclusion: The present data suggest that this resistance exercise paradigm counteracts quadriceps and abates the more substantial triceps surae muscle atrophy in bedridden subjects, and therefore should be an important asset to space travellers. 相似文献
7.
Effects of isokinetic training of the knee extensors on high-intensity exercise performance and skeletal muscle buffering 总被引:1,自引:0,他引:1
A. F. Mannion P. M. Jakeman P. L. T. Willan 《European journal of applied physiology》1994,68(4):356-361
Twenty-three subjects isokinetically trained the right and left quadriceps femoris, three times per week for 16 weeks; one group (n=13) trained at an angular velocity of 4.19 rad · s–1 and a second group (n=10), at 1.05 rad · s–1. A control group (n=10) performed no training. Isometric endurance time at 60% quadriceps maximum voluntary contraction (MVC), mean power output and work done (W) during all-out cycling, and the muscle buffer value (B) and carnosine concentration of biopsy samples from the vastus lateralis, were all assessed before and after training. The two training groups did not differ significantly from each other in their training response to any of these variables (P < 0.05). No significant difference in either 60% MVC endurance time or impulse [(endurance time × force) at 60% MVC] was observed for any group after the 16 week period (P > 0.05). However, the post-training increase (9%) in W during high-intensity cycling was greater in the training group than in the control group (P=0.04). NeitherB nor carnosine concentration showed any significant change following training (P=0.56 andP=0.37, respectively). It is concluded that 16 weeks of isokinetic training of the knee extensors enables subjects to do more work during high-intensity cycling. Although the precise adaptations responsible for the improved performance have yet to be identified, they are unlikely to include an increase inB. 相似文献
8.
《The Knee》2021
BackgroundA single-leg vertical jump height (SLVJ) may reflect knee extension strength more than a single-leg hop for distance (SLH). This study aimed to examine the relationships between the isokinetic knee extension torque, SLH, and SLVJ after anterior cruciate ligament reconstruction (ACLR).MethodsForty-four patients post-ACLR (median 12.0 months) participated in the study. The isokinetic knee extension peak torque at 60°/s and 180°/s (Ext 60, 180), SLH, and SLVJ were measured. The limb symmetry index (LSI) was calculated as the ratio of the operated side to the unoperated side.ResultsThere were moderate-to-strong positive correlations between isokinetic knee extension torque and both SLH (r = 0.72–0.77, P < 0.001) and SLVJ (r = 0.73–0.79, P < 0.001). Significant side-to-side differences in isokinetic knee extension torque and SLVJ between the operated and unoperated sides were found (P < 0.05), but not for SLH (P = 0.065). The results of the analysis of variance (ANOVA) and post hoc analyses showed that the LSI of SLH (98.2%) was higher than that of the LSI of Ext 180 and SLVJ (P < 0.05). Fisher's exact test showed a significant relationship between the LSI of Ext 180 and that of SLVJ (cut-off 85%; P = 0.041). No patients had LSI < 85% in SLH.ConclusionsEven though SLH asymmetry improved approximately 12 months after ACLR, the asymmetry of isokinetic knee extension torque and SLVJ remained. The LSI of SLVJ could be an indicator of the recovery of isokinetic knee extension torque. 相似文献
9.
Muscle strength, volume and activation following 12-month resistance training in 70-year-old males 总被引:2,自引:2,他引:2
Morse CI Thom JM Mian OS Muirhead A Birch KM Narici MV 《European journal of applied physiology》2005,95(2-3):197-204
In elderly males muscle plantar flexor maximal voluntary contraction (MVC) torque normalised to muscle volume (MVC/VOL) is reduced compared to young males as a result of incomplete muscle activation in the elderly. The aim of the present study was to determine the influence of a 12-month resistance training programme on muscle volume, strength, MVC/VOL, agonist activation and antagonist coactivation of the plantarfexors in elderly males. Thirteen elderly males aged 70 years and over (range 70–82 years), completed a 12-month whole body resistance-training programme (TRN), training three times a week. Another eight males (range 18–30 years), who maintained their habitual physical activity for the same 12-month period as the TRN group acted as controls (CTRL). Isometric plantarflexor maximal voluntary contraction (MVC) torque increased in the TRN group by 20% (P<0.01), from 113.1±22.0 Nm to 141.5±19.2 Nm. Triceps surae volume (TS VOL) assessed using MRI, increased by 12%, from 796.3±78.9 cm3 to 916.8±144.4 cm3 . PF activation, measured using supramaximal double twitch interpolation, increased from 83.6±11.0% pre training, to 92.1±7.6% post training (P<0.05). Dorsiflexion MVC and antagonist coactivation (assessed using surface electromyography) did not change with training. Plantarflexor MVC torque normalized for triceps surae muscle volume (MVC/VOL) was 142.6±32.4 kN m–2 before training and 157.0± 27.9 kN m–2 after training (a non-significant increase of 8%). No significant change in any measurement was observed in the CTRL group. This study has shown that the gain in muscle strength in response to long-term (12-month) training in older men is mostly accounted for by an increased muscle volume and activation. 相似文献
10.
Jessica Pingel L. Moerch M. Kjaer H. Langberg 《European journal of applied physiology》2009,106(4):605-611
Skeletal muscles fatigue after exercise, and reductions in maximal force appear. A difference in training status between the
legs was introduced by unilateral immobilization of the calf muscles for 2 weeks in young men, who were randomly assigned
to two groups, either a RUN group (n = 8) that was exposed to prolonged exercise (1-h running: individual pace) or a REST group (n = 12) that did no exercise after immobilization. Cross-sectional area (CSA) of the triceps-surae muscles was calculated by
magnetic resonance imaging (MRI), and maximal voluntary contraction (MVC) force of the plantar flexors was measured before
and after immobilization and after the running protocol. The CSA of triceps-surae muscles decreased significantly with a 7%
reduction in both groups. A significant drop in the MVC of the triceps-surae muscle (10%; P < 0.05) was observed in response to immobilization. When subjected to running exercise immediately after immobilization,
the muscle strength of the triceps-surae muscles dropped even further, but just in the immobilized leg (41%; P < 0.05). The present study highlights the importance of determining the muscle endurance when evaluating the effect of immobilization
on muscle parameters. 相似文献
11.
Surface EMG and mechanomyogram disclose isokinetic training effects on quadriceps muscle in elderly people 总被引:3,自引:0,他引:3
Esposito F Cè E Gobbo M Veicsteinas A Orizio C 《European journal of applied physiology》2005,94(5-6):549-557
Maximum voluntary contraction (MVC) and cross-sectional area (CSA) of fast and slow twitch fibers are reduced in the lower limb muscles of elderly subjects. Isokinetic training at medium and high velocities has been widely used to improve muscle performance and force in young as well as elderly subjects. EMG and mechanomyogram (MMG) are compound signals in which the electrical and mechanical activities of recruited motor units (MUs) are summated. The aim of the present study was to verify the hypothesis that isokinetic training in the elderly induces changes in EMG and MMG parameters, compatible with a functional retrieval of fast twitch fiber MUs. In ten sedentary males (62–78 years), the surface EMG and MMG were recorded from the vastus lateralis muscle during isometric contractions at 20, 40, 60, 80 and 100% of the MVC, before and after 12 weeks of isokinetic training (six series of ten repetitions, each at an angular velocity of 2.09 rad s–1 and 4.19 rad s–1, two times a week). With training: (a) MVC and CSA increased by about 35±5% and 8±1%, respectively (P<0.05); (b) the ratio MVC/CSA increased significantly in all subjects by 25±5%; (c) the EMG root mean square and MMG spectral mean frequency increased significantly at the highest workloads. In conclusion, our data indicate that isokinetic training in the elderly improved muscle size and performance significantly. The EMG and MMG changes suggest that these results may be due to a retrieval of the fast twitch fiber MUs, contributing to muscle action. 相似文献
12.
Requena B Gapeyeva H García I Ereline J Pääsuke M 《European journal of applied physiology》2008,104(3):463-472
Twitch potentiation in knee extensor (KE) muscles after a 7-s conditioning isometric maximal voluntary contraction (MVC trial),
submaximal (25% MVC) voluntary contraction (SVC trial) and submaximal tetanic contraction (25% MVC) induced by percutaneous
electrical stimulation at 100 Hz (PES trial) was compared in 12 men aged 19–25 years. Isometric twitch characteristics of
KE muscles were measured before conditioning contraction and following 10-min recovery by supramaximal electrical stimulation
of the femoral nerve. During MVC trial, twitch peak torque (Pt) potentiated (P < 0.05) immediately after the conditioning contraction with sharp decline during the first and third minute of recovery.
No significant potentiation of twitch Pt was observed in SVC trial. During PES trial, twitch Pt was potentiated (P < 0.05) within 3–10 min of recovery. The time-course of isometric twitch was not significantly altered by conditioning contractions.
It was concluded that twitch potentiation in the KE muscles differed markedly following the three conditioning contractions. 相似文献
13.
Konstantinos Salonikidis Ioannis G. Amiridis Nikolaos Oxyzoglou Eduardo Saez Saez de Villareal Andreas Zafeiridis Eleftherios Kellis 《European journal of applied physiology》2009,107(6):715-722
The association of expertness in specific motor activities with a higher ability to sustain a constant application of force,
regardless of muscle length, has been hypothesized. Ten highly skilled (HS group) young tennis and handball athletes and 10
sedentary (S group) individuals performed maximal and submaximal (5, 10, 20, 50, and 75% of the MVC) isometric wrist flexions
on an isokinetic dynamometer (Kin-Com, Chattanooga). The wrist joint was fixed at five different angles (230, 210, 180, 150,
and 1300). For each position the percentages of the maximal isometric force were calculated and participants were asked to
maintain the respective force level for 5 s. Electromyographic (EMG) activation of the Flexor Carpi Ulnaris and Extensor Digitorum
muscles was recorded using bipolar surface electrodes. No significant differences were observed in maximal isometric strength
between HS and S groups. Participants of HS group showed significantly (P < 0.05) smaller force coefficient of variability (CV) and SD values at all submaximal levels of MVC at all wrist angles.
The CV and SD values remained unaltered regardless of wrist angle. No difference in normalized agonist and antagonist EMG
activity was observed between the two groups. It is concluded that long-term practice could be associated with decreased isometric
force variability independently from muscular length and coactivation of the antagonist muscles. 相似文献
14.
Yasuda T Ogasawara R Sakamaki M Ozaki H Sato Y Abe T 《European journal of applied physiology》2011,111(10):2525-2533
We investigated the combined effect of low-intensity blood flow restriction and high-intensity resistance training on muscle
adaptation. Forty young men (aged 22–32 years) were randomly divided into four groups of ten subjects each: high-intensity
resistance training (HI-RT, 75% of one repetition maximum [1-RM]), low-intensity resistance training with blood flow restriction
(LI-BFR, 30% 1-RM), combined HI-RT and LI-BFR (CB-RT, twice-weekly LI-BFR and once-weekly HI-RT), and nontraining control
(CON). Three training groups performed bench press exercises 3 days/week for 6 weeks. During LI-BFR training sessions, subjects
wore pressure cuffs on both arms that were inflated to 100–160 mmHg. Increases in 1-RM were similar in the HI-RT (19.9%) and
CB-RT (15.3%) groups and lower in the LI-BFR group (8.7%, p < 0.05). Maximal isometric elbow extension (MVC) increased in the HI-RT (11.3%) and CB-RT (6.6%) groups; there was no change
in the LI-BFR group (−0.2%). The cross-sectional area (CSA) of the triceps brachii (TB) increased (p < 0.05) in the HI-RT (8.6%), CB-RT (7.2%), and LI-BFR (4.4%) groups. The change in relative isometric strength (MVC divided
by TB CSA) was greater (p < 0.05) in the HI-RT group (3.3%) than in the LI-BFR (−3.5%) and CON (−0.1%) groups. Following training, relative dynamic
strength (1-RM divided by TB CSA) was increased (p < 0.05) by 10.5% in the HI-RT group and 6.7% in the CB-RT group. None of the variables in the CON group changed. Our results
show that low-intensity resistance training with BFR-induced functional muscle adaptations is improved by combining it with
HI-RT. 相似文献
15.
Krustrup P Ortenblad N Nielsen J Nybo L Gunnarsson TP Iaia FM Madsen K Stephens F Greenhaff P Bangsbo J 《European journal of applied physiology》2011,111(12):2987-2995
The aim of this study was to examine maximal voluntary knee-extensor contraction force (MVC force), sarcoplasmic reticulum
(SR) function and muscle glycogen levels in the days after a high-level soccer game when players ingested an optimised diet.
Seven high-level male soccer players had a vastus lateralis muscle biopsy and a blood sample collected in a control situation
and at 0, 24, 48 and 72 h after a competitive soccer game. MVC force, SR function, muscle glycogen, muscle soreness and plasma
myoglobin were measured. MVC force sustained over 1 s was 11 and 10% lower (P < 0.05) after 0 and 24 h, respectively, compared with control. The rate of SR Ca2+ uptake at 800 nM [Ca2+]free was lower (P < 0.05) after 0 h (2.5 μmol Ca2+ g prot−1 min−1) than for all other time points (24 h: 5.1 μmol Ca2+ g prot−1 min−1). However, SR Ca2+ release rate was not affected. Plasma myoglobin was sixfold higher (P < 0.05) immediately after the game, but normalised 24 h after the game. Quadriceps muscle soreness (0–10 VAS-scale) was higher
(P < 0.05) after 0 h (3.6), 24 h (1.8), 48 h (1.1) and 72 h (1.4) compared with control (0.1). Muscle glycogen was 57 and 27%
lower (P < 0.001) 0 and 24 h after the game compared with control (193 and 328 vs. 449 mmol kg d w−1). In conclusion, maximal voluntary contraction force and SR Ca2+ uptake were impaired and muscle soreness was elevated after a high-level soccer game, with faster recovery of SR function
in comparison with MVC force, soreness and muscle glycogen. 相似文献
16.
Lena Norrbrand Marco Pozzo Per A. Tesch 《European journal of applied physiology》2010,110(5):997-1005
Changes in muscle activation and performance were studied in healthy men in response to 5 weeks of resistance training with
or without “eccentric overload”. Subjects, assigned to either weight stack (grp WS; n = 8) or iso-inertial “eccentric overload” flywheel (grp FW; n = 9) knee extensor resistance training, completed 12 sessions of four sets of seven concentric–eccentric actions. Pre- and
post-measurements comprised maximal voluntary contraction (MVC), rate of force development (RFD) and training mode-specific
force. Root mean square electromyographic (EMGRMS) activity of mm. vastus lateralis and medialis was assessed during MVC and used to normalize EMGRMS for training mode-specific concentric (EMGCON) and eccentric (EMGECC) actions at 90°, 120° and 150° knee joint angles. Grp FW showed greater (p < 0.05) overall normalized angle-specific EMGECC of vastii muscles compared with grp WS. Grp FW showed near maximal normalized EMGCON both pre- and post-training. EMGCON for Grp WS was near maximal only post-training. While RFD was unchanged following training (p > 0.05), MVC and training-specific strength increased (p < 0.05) in both groups. We believe the higher EMGECC activity noted with FW exercise compared to standard weight lifting could be attributed to its unique iso-inertial loading
features. Hence, the resulting greater mechanical stress may explain the robust muscle hypertrophy reported earlier in response
to flywheel resistance training. 相似文献
17.
Beatriz Díaz López Paula Núñez Martínez Elena Díaz Rodríguez Jerónimo Sánchez Bas Nicolás Terrados 《European journal of applied physiology》2010,110(3):549-555
The objectives of the study were to evaluate the influence of a whole training season on 6-sulfatoxymelatonin (αMT6s) and
citrate excretion in 12 elite swimmers. Urine samples were obtained (before bedtime and after waking up) at the beginning
of the season, basic training, macrocycle I, tapering and macrocycle II stages. For αMT6s, at basic training, mainly with
aerobic training, the evening concentrations were significantly lower (P < 0.01; P < 0.05) than at the beginning, tapering and macrocycle II stages. At macrocycle II stage, with the maximal training workload,
the total sum (evening plus morning) was significantly higher (P < 0.05) than at the beginning, basic training and macrocycle I stages. The ratio (morning/evening) that represents the capacity
to produce melatonin at night depending on the evening values at the basic training stage and the nocturnal increment at the
macrocycle II stage were significantly higher (P < 0.01) than at all other stages. Citrate morning values at basic training and tapering stages were significantly lower (P < 0.01) than in the evening indicating that a metabolic recuperation took place. The total sum significantly decreased (P < 0.05) as the aerobic training progressed from the beginning to macrocycle I. The basic training ratio (morning/evening)
was significantly lower compared to the beginning and macrocycle II stages, and the nocturnal increment was significantly
higher (P < 0.05) compared to the beginning. Melatonin and citrate represent complementary markers that could be used to evaluate the
assimilation of the training workload by noninvasive methods. 相似文献
18.
Neuromuscular adaptations in human muscle following low intensity resistance training with vascular occlusion 总被引:1,自引:1,他引:1
Moore DR Burgomaster KA Schofield LM Gibala MJ Sale DG Phillips SM 《European journal of applied physiology》2004,92(4-5):399-406
Low-intensity (~50% of a single repetition maximum—1 RM) resistance training combined with vascular occlusion results in increases in muscle strength and cross-sectional area [Takarada et al. (2002) Eur J Appl Physiol 86:308–331]. The mechanisms responsible for this hypertrophy and strength gain remain elusive and no study has assessed the contribution of neuromuscular adaptations to these strength gains. We examined the effect of low-intensity training (8 weeks of unilateral elbow flexion at 50% 1 RM) both with (OCC) and without vascular occlusion (CON) on neuromuscular changes in the elbow flexors of eight previously untrained men [19.5 (0.4) years]. Following training, maximal voluntary dynamic strength increased (P<0.05) in OCC (22%) and CON (23%); however, isometric maximal voluntary contraction (MVC) strength increased in OCC only (8.3%, P<0.05). Motor unit activation, assessed by interpolated twitch, was high (~98%) in OCC and CON both pre- and post-training. Evoked resting twitch torque decreased 21% in OCC (P<0.05) but was not altered in CON. Training resulted in a reduction in the twitch:MVC ratio in OCC only (29%, P<0.01). Post-activation potentiation (PAP) significantly increased by 51% in OCC (P<0.05) and was not changed in CON. We conclude that low-intensity resistance training in combination with vascular occlusion produces an adequate stimulus for increasing muscle strength and causes changes in indices of neuromuscular function, such as depressed resting twitch torque and enhanced PAP. 相似文献
19.
Effects of a trail running competition on muscular performance and efficiency in well-trained young and master athletes 总被引:1,自引:0,他引:1
Christopher Schmidt Easthope Christophe Hausswirth Julien Louis Romuald Lepers Fabrice Vercruyssen Jeanick Brisswalter 《European journal of applied physiology》2010,110(6):1107-1116
To determine the acute effects of a trail running competition and the age-dependent differences between young and master athletes,
23 subjects [10 young (30.5 ± 7 years), 13 master (45.9 ± 5.9 years)] participated in a 55-km trail running competition. The
study was conceived as an intervention study compromising pre, post 1, 24, 48 and 72 h measurements. Measurements consisted
of blood tests, ergometer cycling and maximal isometric voluntary contractions (MVC). Parameters monitored included MVC, twitch-
and M-wave properties, EMG (RMS) of the vastus lateralis, two locomotion efficiency calculations and muscle damage markers
in the blood (CK, LDH). Results indicate post-race increases in CK and LDH, decreases in MVC values (−32 vs. −40% in young
and master, P < 0.01), decreases in EMG, increases in contraction time and concomitant decreases in peak twitch values, and a decrease
in locomotion efficiency (−4.6 vs. −6.3% in young and master, P < 0.05). Masters showed similar fatigue and muscle damage than young but recuperation was slowed in masters. This study shows
that trail runs are detrimental to muscle function, and gives indication that training may not halt muscle deterioration through
aging, but can help maintain performance level. 相似文献
20.
M. V. Narici G. S. Roi L. Landoni A. E. Minetti P. Cerretelli 《European journal of applied physiology》1989,59(4):310-319
Summary Four male subjects aged 23–34 years were studied during 60 days of unilateral strength training and 40 days of detraining.
Training was carried out four times a week and consisted of six series of ten maximal isokinetic knee extensions at an angular
velocity of 2.09 rad·s−1. At the start and at every 20th day of training and detraining, isometric maximal voluntary contraction (MVC), integrated
electromyographic activity (iEMG) and quadriceps muscle cross-sectional area (CSA) assessed at seven fractions of femur length
(Lf), by nuclear magnetic resonance imaging, were measured on both trained (T) and untrained (UT) legs. Isokinetic torques at
30° before full knee extension were measured before and at the end of training at: 0, 1.05, 2.09, 3.14, 4.19, 5.24 rad·s−1. After 60 days T leg CSA had increased by 8.5%±1.4% (mean±SEM,n=4,p<0.001), iEMG by 42.4%±16.5% (p<0.01) and MVC by 20.8%±5.4% (p<0.01). Changes during detraining had a similar time course to those of training. No changes in UT leg CSA were observed while
iEMG and MVC increased by 24.8%±10% (N.S.) and 8.7%±4.3% (N.S.), respectively. The increase in quadriceps muscle CSA was maximal
at 2/10 Lf (12.0%±1.5%,p<0.01) and minimal, proximally to the knee, at 8/10 Lf (3.5%±1.2%, N.S.). Preferential hypertrophy of the vastus medialis and intermedius muscles compared to those of the rectus
femoris and lateralis muscles was observed. Isoangular torque of T leg increased by 20.9%±5.4% (p<0.05), 23.8%±7.8% (p<0.05) and 22.5%±6.7% (p<0.05) at 0, 1.05 and 2.09 rad·s−1 respectively; no significant change was observed at higher velocities and in the UT leg. Hypertrophy produced by strength
training accounts for 40% of the increase in force while the remaining 60% seems to be attributable to an increased neural
drive and possibly to changes in muscle architecture. 相似文献