Search results for "Isometric exercise"
showing 10 items of 449 documents
Neural drive preservation after detraining following neuromuscular electrical stimulation training
2006
The purpose of the study was to investigate the behaviour of the central nervous system when 5 weeks of neuromuscular electrical stimulation (NMES) training was followed by 5 weeks of detraining. Nineteen males were divided into the neuromuscular electrostimulated group (EG, n=12) and the control group (CG, n=7). The training program consisted of 15 sessions of isometric NMES over a 5-week period. The EG subjects were tested before training (PRE), after 5 weeks of NMES training (POST) and after 5 weeks of detraining (DE) while CG subjects were only tested at PRE and at POST. Soleus (SOL) and gastrocnemii (GAS) maximal H-reflex and M-wave potentials were evoked at rest (i.e., H(max) and M(ma…
Effects of fatigue on isometric force- and relaxation-time characteristics in human muscle
1981
Effects of intermittent one leg isometric fatigue on maximal isometric force, force production, relaxation and blood lactate were studied using 29 male students as subjects. The relative changes of variables during fatigue and recovery were intercorrelated together with muscle structure variables, which were determined using needle biopsy technique. Maximal force decreased, force production and relaxation became slower and muscle lactate increased during fatigue. Change of maximal force, force production and lactate during fatigue as well as recovery of maximal force and lactate after fatigue were correlated significantly to muscle fiber distribution. Fatiguability of the force-time charact…
Mechanisms contributing to knee extensor strength loss after prolonged running exercise.
2002
The aim of this study was to identify the mechanisms that contribute to the decline in knee extensor (KE) muscles strength after a prolonged running exercise. During the 2 days preceding a 30-km running race [duration 188.7 ± 27.0 (SD) min] and immediately after the race, maximal percutaneous electrical stimulations (single twitch, 0.5-s tetanus at 20 and 80 Hz) were applied to the femoral nerve of 12 trained runners. Superimposed twitches were also delivered during isometric maximal voluntary contraction (MVC) to determine the level of voluntary activation (%VA). The vastus lateralis electromyogram was recorded. KE MVC decreased from pre- to postexercise (from 188.1 ± 25.2 to 142.7 ± 29.7…
Comparison between voluntary and stimulated contractions of the quadriceps femoris for growth hormone response and muscle damage
2007
This study aimed to compare voluntary and stimulated exercise for changes in muscle strength, growth hormone (GH), blood lactate, and markers of muscle damage. Nine healthy men had two leg press exercise bouts separated by 2 wk. In the first bout, the quadriceps muscles were stimulated by biphasic rectangular pulses (75 Hz, duration 400 μs, on-off ratio 6.25–20 s) with current amplitude being consistently increased throughout 40 contractions at maximal tolerable level. In the second bout, 40 voluntary isometric contractions were performed at the same leg press force output as the first bout. Maximal voluntary isometric strength was measured before and after the bouts, and serum GH and blood…
Training-induced changes in neuromuscular performance under voluntary and reflex conditions.
1986
To investigate training-induced changes in neuromuscular performance under voluntary and reflex contractions, 11 male subjects went through heavy resistance (high loads of 70-120% of one maximum repetition) and 10 male subjects through explosive type (low loads with high contraction velocities) strength training three times a week for 24 weeks. A large increase (13.9%, p less than 0.01) in voluntary unilateral maximal knee extension strength with only slight and insignificant changes in time of isometric force production were observed during heavy resistance strength training. Explosive type strength training resulted in a small insignificant increase in maximal strength but in considerable…
Similar increases in strength after short-term resistance training due to different neuromuscular adaptations in young and older men
2014
This study investigated whether differences in neuromuscular performance and muscle hypertrophy occur between young and older men. Twenty-three young (29 ± 9 years) and 26 older men (64 ± 8 years) completed 10 weeks of high-volume, medium load “hypertrophic” resistance training with low frequency (twice per week) with 10 young (34 ± 11 years) and 11 older men (65 ± 3 years) acting as nontraining control subjects. Training consisted of 2–5 sets of 8–14 repetitions (1- to 2-minute rest). Lower-limb dynamic (leg press) and isometric maximum leg extension force, as well as lower-limb lean mass and vastus lateralis cross-sectional area were assessed before and after the training period. Training…
Frequent blood flow restricted training not to failure and to failure induces similar gains in myonuclei and muscle mass
2021
The purpose of the present study was to compare the effects of short-term high-frequency failure vs non-failure blood flow–restricted resistance exercise (BFRRE) on changes in satellite cells (SCs), myonuclei, muscle size, and strength. Seventeen untrained men performed four sets of BFRRE to failure (Failure) with one leg and not to failure (Non-failure; 30-15-15-15 repetitions) with the other leg using knee-extensions at 20% of one repetition maximum (1RM). Fourteen sessions were distributed over two 5-day blocks, separated by a 10-day rest period. Muscle samples obtained before, at mid-training, and 10-day post-intervention (Post10) were analyzed for muscle fiber area (MFA), myonuclei, an…
Muscle strength in healthy people and in patients suffering from recent-onset inflammatory arthritis.
1995
Neuromuscular function was compared among 20 patients with relatively recent onset (symptomatic period 17 +/- 24 months) rheumatoid arthritis (RA) (experimental group; EG), and 20 age- and sex-matched healthy people (control group; CG). The comparison was repeated after a period of 6 months, when 16 patients had carried out progressive strength training. At baseline maximal grip strength and maximal dynamic unilateral strength of the knee extensors in the EG were significantly (P < 0.05) lower in comparison to the CG. The groups did not differ from each other in maximal isometric strength of the trunk flexors and extensors or the knee extensors. The 6-month dynamic strength training in the …
Effect of time-of-day-specific strength training on muscular hypertrophy in men.
2009
The purpose of the present study was to examine effects of time-of-day-specific strength training on muscle hypertrophy and maximal strength in men. A training group underwent a 10-week preparatory training (wk 0-wk 10) scheduled between 17:00 and 19:00 hours. Thereafter, the subjects were randomized either to a morning or afternoon training group. They continued with a 10-week time-of-day-specific training (wk 11-wk 20) with training times between 07:00 and 09:00 hours and 17:00 and 19:00 hours in the morning group and afternoon groups, respectively. A control group did not train but was tested at all occasions. Quadriceps femoris (QF) cross-sectional areas (CSA) and volume were obtained b…
Evolution of electromyographic signal, running economy, and perceived exertion during different prolonged exercises
2000
International audience; The purpose of this study was to compare the electromyographic (EMG) signal of the vastus lateralis muscle obtained during a run section of a triathlon and at the end of a prolonged run performed at the same running velocity. Seven subjects were studied on three occasions: a 2 h 15 min triathlon (30 min swimming, 60 min cycling, and 45 min treadmill running at 75% of the maximal aerobic speed), a 2 h 15 min run, where the last 45 min (Prolonged Run, PR) were run at the same speed as the Triathlon Run (TR) on a motorized treadmill, and a 45 min Isolated Run (IR) performed at the same TR and PR velocity. The three experimental trials were randomised. Oxygen uptake (VO …