Search results for "Neural adaptation"
showing 7 items of 7 documents
Evidence of resistance training-induced neural adaptation in older adults
2021
The deleterious effects of aging on force production are observable from the age of 40 upwards, depending on the measure. Neural mechanisms contributing to maximum force production and rate of force development have been suggested as descending drive from supraspinal centers, spinal motoneuron excitability, and corticospinal inhibition of descending drive; all of which influence motor unit recruitment and/or firing rate. Resistance-trained Master athletes offer a good source of information regarding the inevitable effects of aging despite the countermeasure of systematic resistance-training. However, most evidence of neural adaptation is derived from longitudinal intervention studies in pre…
Plasma catecholamine responses and neural adaptation during short-term resistance training
2000
Low exercise-induced plasma adrenaline (A) responses have been reported in resistance-trained indi- viduals. 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 exten- sions 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 (a…
Alternative methods for strength development : the case of motor imagery and neuromuscular electrical stimulation
2020
An intense practice of resistance training, i.e. with heavy loads and a low number of repetitions, can cause injuries. To avoid them or limit detraining after an injury, alternative training methods have been developed. These methods have a double target since they also allow populations with different pathologies to practice a physical activity. This thesis focused particularly on the neuromuscular system and the mechanisms involved in strength development on plantar flexors muscles following motor imagery (MI), i.e. mental simulation of a movement without its concomitant motor output, and neuromuscular electrical stimulation (NMES), i.e. evoking contractions through electrical current app…
Neuromuscular adaptations to constant vs. variable resistance training in older men.
2013
This study examined the effects of constant or variable external resistance training on neuromuscular adaptations in the lower limbs of older men. 37 subjects (age 65±4 year) were quasi-randomly assigned to the constant or variable training group, or a non-training control group. Training consisted of a 20-week medium-intensity, high volume resistance training program. Maximum bilateral concentric and isometric force production of the leg extensors as well as repetitions-to-failure test were performed pre-, mid- and post-training. Vastus lateralis muscle cross-sectional area was assessed by ultrasound and lean leg mass was assessed by dual-energy x-ray absorptiometry. Both training groups s…
Strength athletes are capable to produce greater muscle activation and neural fatigue during high-intensity resistance exercise than nonathletes.
2009
Acute neuromuscular responses to maximum versus forced repetition (FR) knee extension resistance exercises (4 sets of 12 repetitions [reps] with a 2-minute recovery between the sets) were examined in 4 male strength athletes (SAs) and 4 nonathletes. Maximum repetition (MR) sets were performed to voluntary exhaustion (12 repetition maximum [RM]), whereas in the FR sets, the load was greater (8RM) and the set was continued after voluntary fatigue with 4 additional assisted reps. Maximal isometric force and electromyogram (EMG) activity of the knee extensors were measured before and after the exercise, as well as 2 recovery days after the exercise. Electromyogram activity was also measured dur…
Neural Adaptation to Optical Quality Defects
2010
From an optical perspective the eye is far from perfect. This is a fact that is extensively supported by literature; for instance, Prof. Navarro recently provided us with a fantastic critical review on the various theories behind the different eye models and their flaws.1 The human eye has considerable amounts of higher-order aberrations even when it is emmetropic,2 with great inter-individual variability. Besides, higher-order aberrations are still postulated to have a role in the development of the refractive error, although it is not clear the extent to which this may be (see Charman WN for a review).3 The known optical limitations of the normal human eye raised the question as to what t…
Mismatch negativity (MMN) in freely-moving rats with several experimental controls.
2014
Mismatch negativity (MMN) is a scalp-recorded electrical potential that occurs in humans in response to an auditory stimulus that defies previously established patterns of regularity. MMN amplitude is reduced in people with schizophrenia. In this study, we aimed to develop a robust and replicable rat model of MMN, as a platform for a more thorough understanding of the neurobiology underlying MMN. One of the major concerns for animal models of MMN is whether the rodent brain is capable of producing a human-like MMN, which is not a consequence of neural adaptation to repetitive stimuli. We therefore tested several methods that have been used to control for adaptation and differential exogenou…