Effects of eccentric training on torque-angular velocity-power characteristics of elbow flexor muscles in older women.
TL;DR: Gains in maximal torque, Pmax and VImax observed after training would result more from intramuscular modifications than from changes in muscular activity, except for eccentric condition at -30 degrees s(-1) where the torque gains could also be partly explained by a reduction in inhibition of the motor unit pool.
About: This article is published in Experimental Gerontology.The article was published on 2004-03-01. It has received 36 citations till now. The article focuses on the topics: Eccentric training & Eccentric.
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TL;DR: Eccentric exercise is a promising training modality with many different domains of application, however, more research work is needed to better understand how the neuromuscular system adapts to ECC exercise training in order to optimize and better individualize future ECC training strategies.
Abstract: Eccentric (ECC) exercise is classically used to improve muscle strength and power in healthy subjects and athletes. Due to its specific physiological and mechanical properties, there is an increasing interest in employing ECC muscle work for rehabilitation and clinical purposes. Nowadays, ECC muscle actions can be generated using various exercise modalities that target small or large muscle masses with minimal or no muscle damage or pain. The most interesting feature of ECC muscle actions is to combine high muscle force with a low energy cost (typically 4- to 5-times lower than concentric muscle work) when measured during leg cycle ergometry at a similar mechanical power output. Therefore, if caution is taken to minimize the occurrence of muscle damage, ECC muscle exercise can be proposed not only to athletes and healthy subjects, but also to individuals with moderately to severely limited exercise capacity, with the ultimate goal being to improve their functional capacity and quality of life. The first part of this review article describes the available exercise modalities to generate ECC muscle work, including strength and conditioning exercises using the body's weight and/or additional external loads, classical isotonic or isokinetic exercises and, in addition, the oldest and newest specifically designed ECC ergometers. The second part highlights the physiological and mechanical properties of ECC muscle actions, such as the well-known higher muscle force-generating capacity and also the often overlooked specific cardiovascular and metabolic responses. This point is particularly emphasized by comparing ECC and concentric muscle work performed at similar mechanical (i.e., cycling mechanical power) or metabolic power (i.e., oxygen uptake, VO2). In particular, at a similar mechanical power, ECC muscle work induces lower metabolic and cardiovascular responses than concentric muscle work. However, when both exercise modes are performed at a similar level of VO2, a greater cardiovascular stress is observed during ECC muscle work. This observation underlines the need of cautious interpretation of the heart rate values for training load management because the same training heart rate actually elicits a lower VO2 in ECC muscle work than in concentric muscle work. The last part of this article reviews the documented applications of ECC exercise training and, when possible, presents information on single-joint movement training and cycling or running training programs, respectively. The available knowledge is then summarized according to the specific training objectives including performance improvement for healthy subjects and athletes, and prevention of and/or rehabilitation after injury. The final part of the article also details the current knowledge on the effects of ECC exercise training in elderly populations and in patients with chronic cardiac, respiratory, metabolic or neurological disease, as well as cancer. In conclusion, ECC exercise is a promising training modality with many different domains of application. However, more research work is needed to better understand how the neuromuscular system adapts to ECC exercise training in order to optimize and better individualize future ECC training strategies.
158 citations
Cites background from "Effects of eccentric training on to..."
...1 Single Joint Movements Compared to standard strength exercises, ECC overload and isokinetic exercises can lead to better strength gains in older individuals [182, 183] (Table 3)....
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TL;DR: This review will summarise the changes of the f-v relationship with age, the functional implications of these changes and the various methods to reverse or at least partly ameliorate these changes.
140 citations
Cites background from "Effects of eccentric training on to..."
...Valour et al. (2004) explored the effect of 7 weeks of elbow flexor ERT performed 3 times a week on elbow flexor characteristics in 8 older female adults (mean age 65 ± 6 years)....
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31 Oct 2009
TL;DR: A review of the changes of the force-velocity relationship with age, the functional implications of these changes and the various methods to reverse or at least partly ameliorate these changes can be found in this article.
Abstract: Aging in humans is associated with a loss in neuromuscular function and performance. This is related, in part, to the reduction in muscular strength and power caused by a loss of skeletal muscle mass (sarcopenia) and changes in muscle architecture. Due to these changes, the force-velocity (f-v) relationship of human muscles alters with age. This change has functional implications such as slower walking speeds. Different methods to reverse these changes have been investigated, including traditional resistance training, power training and eccentric (or eccentrically-biased) resistance training. This review will summarise the changes of the f-v relationship with age, the functional implications of these changes and the various methods to reverse or at least partly ameliorate these changes.
129 citations
TL;DR: The literature tends to show that isotonic mode leads to a greater strength gain than isokinetic mode, which could be explained by a greater neuromuscular activation after IT training.
112 citations
Cites background from "Effects of eccentric training on to..."
...Il est de ce point de vue intéressant de noter que les gains d’activation musculaire sont plus élevés après un entraı̂nement excentrique IT (+1,80 1,54 % par séance) [19,27,92,125], par rapport à un entraı̂nement excentrique IK (+0,43 0,17 % par séance) [40,43,58,115]....
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...54% per session) [19,27,92,125], compared to IK eccentric training (+0....
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TL;DR: Increased muscle thickness due to eccentric training was related to increased fascicle length and not to pennation angle changes, and although RF and VL have a different fascicular geometry, they had similar morphological adaptations to eccentricTraining.
Abstract: Introduction: Changes in muscle architecture induced by eccentric knee extensor training remain unclear, as well the adaptive responses of synergistic knee extensor muscles with different geometrical designs. Methods: Ultrasonography images were taken from rectus femoris (RF) and vastus lateralis (VL) of 20 male volunteers before and after a non-training control period of 4 weeks, and additional evaluations were performed after 4, 8, and 12 weeks of isokinetic eccentric training. Results: RF and VL had significant changes in muscle architecture within the first 4 training weeks, and the adaptive response throughout the intervention was similar. Muscle thickness increased by around 7–10%, fascicle length increased 17–19%, and pennation angle was unchanged. Conclusions: Increased muscle thickness due to eccentric training was related to increased fascicle length and not to pennation angle changes. Although RF and VL have a different fascicular geometry, they had similar morphological adaptations to eccentric training. Muscle Nerve 48: 498–506, 2013
106 citations
References
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TL;DR: In this article, a more accurate and rapid technique for muscle heat measurement was proposed, and some astonishingly simple and accurate relations have been found, which determine the effect of load on speed of shortening, allow the form of the isometric contraction to be predicted, and are the basis of the so-called "visco-elasticity" of skeletal muscle.
Abstract: The hope was recently expressed (Hill 1937, p. 116) that with the development of a more accurate and rapid technique for muscle heat measurement, a much more consistent picture might emerge of the energy relations of muscles shortening (or lengthening) and doing positive (or negative) work. This hope has been realized, and some astonishingly simple and accurate relations have been found, relations, moreover, which (among other things) determine the effect of load on speed of shortening, allow the form of the isometric contraction to be predicted, and are the basis of the so-called “visco-elasticity” of skeletal muscle. This paper is divided into three parts. In Part I further developments of the technique are described: everything has depended on the technique, so no apology is needed for a rather full description of it and of the precautions necessary. In Part II the results themselves are described and discussed. In Part III the “visco-elastic” properties of active muscle are shown to be a consequence of the properties described in Part II.
4,672 citations
TL;DR: It is suggested that a quantitative loss in muscle CSA is a major contributor to the decrease in muscle strength seen with advancing age and accounts for 90% of the variability in strength at T2.
Abstract: The present study examines age-related changes in skeletal muscle size and function after 12 yr. Twelve healthy sedentary men were studied in 1985–86 (T1) and nine (initial mean age 65.4 ± 4.2 yr) ...
1,378 citations
TL;DR: Strength gains in older men were associated with significant muscle hypertrophy and an increase in myofibrillar protein turnover and the torque-velocity relationship showed an upward displacement of the curve at the end of training, mainly in the slow-vel velocity high-torque region.
Abstract: The effects of strength conditioning on skeletal muscle function and mass were determined in older men. Twelve healthy untrained volunteers (age range 60-72 yr) participated in a 12-wk strength training program (8 repetitions/set; 3 sets/day; 3 days/wk) at 80% of the one repetition maximum (1 RM) for extensors and flexors of both knee joints. They were evaluated before the program and after 6 and 12 wk of training. Weekly measurements of 1 RM showed a progressive increase in strength in extensors and flexors. By 12 wk extensor and flexor strength had increased 107.4 (P less than 0.0001) and 226.7% (P less than 0.0001), respectively. Isokinetic peak torque of extensors and flexors measured on a Cybex II dynamometer increased 10.0 and 18.5% (P less than 0.05) at 60 degrees/s and 16.7 and 14.7% (P less than 0.05) at 240 degrees/s. The torque-velocity relationship showed an upward displacement of the curve at the end of training, mainly in the slow-velocity high-torque region. Midthigh composition from computerized tomographic scans showed an increase (P less than 0.01) in total thigh area (4.8%), total muscle area (11.4%), and quadriceps area (9.3%). Biopsies of the vastus lateralis muscle revealed similar increases (P less than 0.001) in type I fiber area (33.5%) and type II fiber area (27.6%). Daily excretion of urinary 3-methyl-L-histidine increased with training (P less than 0.05) by an average 40.8%. Strength gains in older men were associated with significant muscle hypertrophy and an increase in myofibrillar protein turnover.
1,343 citations
TL;DR: The possible mechanisms of neural adaptation are discussed in relation to motor unit recruitment and firing patterns and the relative roles of neural and muscular adaptation in short- and long-term strength training are evaluated.
Abstract: Strength performance depends not only on the quantity and quality of the involved muscles, but also upon the ability of the nervous system to appropriately activate the muscles. Strength training may cause adaptive changes within the nervous system that allow a trainee to more fully activate prime movers in specific movements and to better coordinate the activation of all relevant muscles, thereby effecting a greater net force in the intended direction of movement. The evidence indicating neural adaptation is reviewed. Electromyographic studies have provided the most direct evidence. They have shown that increases in peak force and rate of force development are associated with increased activation of prime mover muscles. Possible reflex adaptations related to high stretch loads in jumping and rapid reciprocal movements have also been revealed. Other studies, including those that demonstrate the "cross-training" effect and specificity of training, provide further evidence of neural adaptation. The possible mechanisms of neural adaptation are discussed in relation to motor unit recruitment and firing patterns. The relative roles of neural and muscular adaptation in short- and long-term strength training are evaluated.
1,308 citations
TL;DR: Measurement of leg extensor power in frail elderly people may prove useful in focusing effective rehabilitation programmes because of the relation within the group between age and any of the variables measured.
Abstract: 1. Residents of a chronic care hospital (13 men of mean age 88.5 ± 6 sd years and 13 women of mean age 86.5 ± 6 sd years) who had multiple pathologies were assessed for leg extensor capability in several ways. 2. A custom-built rig was used to assess leg extensor power, that is, maximal power output over less than 1 s in a single extension of one leg. Performance measures were obtained by timing chair rises (from a standard chair 0.43 m high), stair climbing (four risers, total height 0.635 m) and a walk (6.1 m). For each measurement the best of several trials were recorded as definitive. 3. Leg extensor power was significantly correlated with all performance measures, but the performance measures were not related to each other except for chair rising and walking speed. 4. Women had significantly less extensor power than men, but their power explained more of the variance in performance, e.g. power accounted for 86% of the variance in walking speed. 5. There was no relation within the group between age and any of the variables measured. 6. Measurement of leg extensor power in frail elderly people may prove useful in focusing effective rehabilitation programmes.
961 citations