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Serge S. Colson

Bio: Serge S. Colson is an academic researcher from University of Nice Sophia Antipolis. The author has contributed to research in topics: Isometric exercise & Whole body vibration. The author has an hindex of 15, co-authored 51 publications receiving 862 citations. Previous affiliations of Serge S. Colson include University of the South, Toulon-Var & University of Burgundy.


Papers
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Journal ArticleDOI
TL;DR: It is concluded that high-frequency/high peak-to-peak displacement was the most effective vibration setting to enhance knee extensor muscle strength and jump performance during a 6-week WBV training program and that these improvements were not mediated by central neural adaptations.

85 citations

Journal ArticleDOI
TL;DR: It is suggested that steadiness is an independent predictor of brief, stressful functional-performance tasks in older women with mild functional impairment and improving steadiness might help reduce functional limitations or disability in older adults.
Abstract: The relationship between isometric force control and functional performance is unknown. Submaximal steadiness and accuracy were measured during a constant force-matching task at 50% of maximal isometric voluntary contraction (MVC) of the knee extensors in 19 older women (70-89 years). Other variables included MVC, rate of torque development, and EMG activity. Functional performance was assessed during maximal performance of walking endurance, chair rising, and stair climbing. Isometric steadiness (but not accuracy) was found to independently predict chair-rise time and stair-climbing power and explained more variance in these tasks than any other variable. Walking endurance was related to muscle strength but not steadiness. These results suggest that steadiness is an independent predictor of brief, stressful functional-performance tasks in older women with mild functional impairment. Thus, improving steadiness might help reduce functional limitations or disability in older adults.

81 citations

Journal ArticleDOI
TL;DR: The influence of eccentric training on the torque gains under eccentric conditions and for the highest velocities was attributed essentially to neural adaptations.

72 citations

Journal ArticleDOI
TL;DR: The individualized physical activity program improved the postural stability of older people when the standing position was challenged, however, the lack of significant results for the hard floor condition suggests that three months is not sufficient to improve static balance.
Abstract: Background and aims: The objective of this non-randomized study was to determine the influence of a specific physical activity program on the postural stability of older people. Methods: Seventy-four subjects (72.4±0.7 yrs) participated in an individualized three-month physical activity program designed to improve posture, balance and mobility — the PBM program. Sessions were held twice weekly. Postural stability was assessed using a force platform, subjects being in static and dynamic conditions, and with open and closed eyes. Changes in stabilometric parameters (Sway area, ML mean, AP mean, Total length, ML length and AP length) of the intervention group were compared to those of 14 control subjects (71.8±1.5 years). Results: A two-way analysis of variance with repeated measures did not show any significant post-program change in postural stability in the hard floor condition. In contrast, Sway area (p<0.0005), Total length (p<0.001) and AP length (p<0.01) were significantly reduced after the training program in the foam floor condition, with open and closed eyes. In addition, in the mediolateral axis condition and with closed eyes, AP length in the intervention group was significantly reduced (p<0.01, and in the antero-posterior axis condition with both open and closed eyes, Sway area (p<0.0005), Total length (p<0.0005) and AP length (p<0.05) decreased significantly. Conclusions: As shown by the results in the foam floor and dynamic conditions, our individualized physical activity program improved the postural stability of older people when the standing position was challenged. However, the lack of significant results for the hard floor condition suggests that three months is not sufficient to improve static balance. The PBM physical activity program can be used for balance training in older people, but further studies are required to determine the time needed to effect improvements in static balance in this population.

62 citations

Journal ArticleDOI
TL;DR: Cox values were severely reduced - though not characteristic of a hypofrontality state - while no sign of deficit in selective response inhibition was observed, and individual's susceptibility to making fast impulsive errors increased and less efficient online correction of incorrect activation was observed near exhaustion.

61 citations


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Journal ArticleDOI
TL;DR: The gains in strength with HRST are undoubtedly due to a wide combination of neurological and morphological factors, although there is contrary evidence suggesting no change in cortical or corticospinal excitability.
Abstract: High-resistance strength training (HRST) is one of the most widely practiced forms of physical activity, which is used to enhance athletic performance, augment musculo-skeletal health and alter body aesthetics. Chronic exposure to this type of activity produces marked increases in muscular strength, which are attributed to a range of neurological and morphological adaptations. This review assesses the evidence for these adaptations, their interplay and contribution to enhanced strength and the methodologies employed. The primary morphological adaptations involve an increase in the cross-sectional area of the whole muscle and individual muscle fibres, which is due to an increase in myofibrillar size and number. Satellite cells are activated in the very early stages of training; their proliferation and later fusion with existing fibres appears to be intimately involved in the hypertrophy response. Other possible morphological adaptations include hyperplasia, changes in fibre type, muscle architecture, myofilament density and the structure of connective tissue and tendons. Indirect evidence for neurological adaptations, which encompasses learning and coordination, comes from the specificity of the training adaptation, transfer of unilateral training to the contralateral limb and imagined contractions. The apparent rise in whole-muscle specific tension has been primarily used as evidence for neurological adaptations; however, morphological factors (e.g. preferential hypertrophy of type 2 fibres, increased angle of fibre pennation, increase in radiological density) are also likely to contribute to this phenomenon. Changes in inter-muscular coordination appear critical. Adaptations in agonist muscle activation, as assessed by electromyography, tetanic stimulation and the twitch interpolation technique, suggest small, but significant increases. Enhanced firing frequency and spinal reflexes most likely explain this improvement, although there is contrary evidence suggesting no change in cortical or corticospinal excitability. The gains in strength with HRST are undoubtedly due to a wide combination of neurological and morphological factors. Whilst the neurological factors may make their greatest contribution during the early stages of a training programme, hypertrophic processes also commence at the onset of training.

1,086 citations

Journal ArticleDOI
TL;DR: The last line of evidence presented involves the notion that unilateral resistive exercise of a specific limb will also result in training effects in the unexercised contralateral limb (cross-transfer or cross-education).
Abstract: It is generally accepted that neural factors play an important role in muscle strength gains. This article reviews the neural adaptations in strength, with the goal of laying the foundations for practical applications in sports medicine and rehabilitation. An increase in muscular strength without noticeable hypertrophy is the first line of evidence for neural involvement in acquisition of muscular strength. The use of surface electromyographic (SEMG) techniques reveal that strength gains in the early phase of a training regimen are associated with an increase in the amplitude of SEMG activity. This has been interpreted as an increase in neural drive, which denotes the magnitude of efferent neural output from the CNS to active muscle fibres. However, SEMG activity is a global measure of muscle activity. Underlying alterations in SEMG activity are changes in motor unit firing patterns as measured by indwelling (wire or needle) electrodes. Some studies have reported a transient increase in motor unit firing rate. Training-related increases in the rate of tension development have also been linked with an increased probability of doublet firing in individual motor units. A doublet is a very short interspike interval in a motor unit train, and usually occurs at the onset of a muscular contraction. Motor unit synchronisation is another possible mechanism for increases in muscle strength, but has yet to be definitely demonstrated. There are several lines of evidence for central control of training-related adaptation to resistive exercise. Mental practice using imagined contractions has been shown to increase the excitability of the cortical areas involved in movement and motion planning. However, training using imagined contractions is unlikely to be as effective as physical training, and it may be more applicable to rehabilitation. Retention of strength gains after dissipation of physiological effects demonstrates a strong practice effect. Bilateral contractions are associated with lower SEMG and strength compared with unilateral contractions of the same muscle group. SEMG magnitude is lower for eccentric contractions than for concentric contractions. However, resistive training can reverse these trends. The last line of evidence presented involves the notion that unilateral resistive exercise of a specific limb will also result in training effects in the unexercised contralateral limb (cross-transfer or cross-education). Peripheral involvement in training-related strength increases is much more uncertain. Changes in the sensory receptors (i.e. Golgi tendon organs) may lead to disinhibition and an increased expression of muscular force. Agonist muscle activity results in limb movement in the desired direction, while antagonist activity opposes that motion. Both decreases and increases in co-activation of the antagonist have been demonstrated. A reduction in antagonist co-activation would allow increased expression of agonist muscle force, while an increase in antagonist co-activation is important for maintaining the integrity of the joint. Thus far, it is not clear what the CNS will optimise: force production or joint integrity. The following recommendations are made by the authors based on the existing literature. Motor learning theory and imagined contractions should be incorporated into strength-training practice. Static contractions at greater muscle lengths will transfer across more joint angles. Submaximal eccentric contractions should be used when there are issues of muscle pain, detraining or limb immobilisation. The reversal of antagonists (antagonist-to-agonist) proprioceptive neuromuscular facilitation contraction pattern would be useful to increase the rate of tension development in older adults, thus serving as an important prophylactic in preventing falls. When evaluating the neural changes induced by strength training using EMG recording, antagonist EMG activity should always be measured and evaluated.

675 citations

01 Jan 2005
TL;DR: In this article, the authors used TgCRND8 mice to examine directly the interaction between exercise and the AD cascade, and found that five months of voluntary exercise resulted in a decrease in extracellular amyloid-β (Aβ) plaques in the frontal cortex.
Abstract: Alzheimer's disease (AD) is a progressive neurodegenerative disorder for which there are few therapeutics that affect the underlying disease mechanism. Recent epidemiological studies, however, suggest that lifestyle changes may slow the onset/progression of AD. Here we have used TgCRND8 mice to examine directly the interaction between exercise and the AD cascade. Five months of voluntary exercise resulted in a decrease in extracellular amyloid-β (Aβ) plaques in the frontal cortex (38%; p = 0.018), the cortex at the level of the hippocampus (53%; p = 0.0003), and the hippocampus (40%; p = 0.06). This was associated with decreased cortical Aβ1-40 (35%; p = 0.005) and Aβ1-42 (22%; p = 0.04) (ELISA). The mechanism appears to be mediated by a change in the processing of the amyloid precursor protein (APP) after short-term exercise, because 1 month of activity decreased the proteolytic fragments of APP [for α-C-terminal fragment (α-CTF), 54% and p = 0.04; for β-CTF, 35% and p = 0.03]. This effect was independent of mRNA/protein changes in neprilysin and insulin-degrading enzyme and, instead, may involve neuronal metabolism changes that are known to affect APP processing and to be regulated by exercise. Long-term exercise also enhanced the rate of learning of TgCRND8 animals in the Morris water maze, with significant (p < 0.02) reductions in escape latencies over the first 3 (of 6) trial days. In support of existing epidemiological studies, this investigation demonstrates that exercise is a simple behavioral intervention sufficient to inhibit the normal progression of AD-like neuropathology in the TgCRND8 mouse model.

674 citations

Journal ArticleDOI
TL;DR: In this part of the review, the different aspects of HIT programming are discussed, from work/relief interval manipulation to HIT periodization, using different examples of training cycles from different sports, with continued reference to the cardiorespiratory adaptations outlined in Part I.
Abstract: High-intensity interval training (HIT) is a well-known, time-efficient training method for improving cardiorespiratory and metabolic function and, in turn, physical performance in athletes. HIT involves repeated short (<45 s) to long (2–4 min) bouts of rather high-intensity exercise interspersed with recovery periods (refer to the previously published first part of this review). While athletes have used ‘classical’ HIT formats for nearly a century (e.g. repetitions of 30 s of exercise interspersed with 30 s of rest, or 2–4-min interval repetitions ran at high but still submaximal intensities), there is today a surge of research interest focused on examining the effects of short sprints and all-out efforts, both in the field and in the laboratory. Prescription of HIT consists of the manipulation of at least nine variables (e.g. work interval intensity and duration, relief interval intensity and duration, exercise modality, number of repetitions, number of series, between-series recovery duration and intensity); any of which has a likely effect on the acute physiological response. Manipulating HIT appropriately is important, not only with respect to the expected middle- to long-term physiological and performance adaptations, but also to maximize daily and/or weekly training periodization. Cardiopulmonary responses are typically the first variables to consider when programming HIT (refer to Part I). However, anaerobic glycolytic energy contribution and neuromuscular load should also be considered to maximize the training outcome. Contrasting HIT formats that elicit similar (and maximal) cardiorespiratory responses have been associated with distinctly different anaerobic energy contributions. The high locomotor speed/power requirements of HIT (i.e. ≥95 % of the minimal velocity/power that elicits maximal oxygen uptake [v/p $$ \dot{V} $$ O2max] to 100 % of maximal sprinting speed or power) and the accumulation of high-training volumes at high-exercise intensity (runners can cover up to 6–8 km at v $$ \dot{V} $$ O2max per session) can cause significant strain on the neuromuscular/musculoskeletal system. For athletes training twice a day, and/or in team sport players training a number of metabolic and neuromuscular systems within a weekly microcycle, this added physiological strain should be considered in light of the other physical and technical/tactical sessions, so as to avoid overload and optimize adaptation (i.e. maximize a given training stimulus and minimize musculoskeletal pain and/or injury risk). In this part of the review, the different aspects of HIT programming are discussed, from work/relief interval manipulation to HIT periodization, using different examples of training cycles from different sports, with continued reference to the cardiorespiratory adaptations outlined in Part I, as well as to anaerobic glycolytic contribution and neuromuscular/musculoskeletal load.

631 citations

ComponentDOI
12 Aug 2014-PLOS ONE

394 citations