A comparison of concentric, eccentric, and isometric strength of elbow flexors

Doss, Wayne S.; Karpovich, Peter V.

doi:10.1152/jappl.1965.20.2.351

Cited by 95 publications

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“…As in the previous studies (e.g., Doss and Karpovich 1965;Komi 1973;Komi et al 2000), in the present study the average force level associated with concentric actions was lower than that associated with eccentric force. Although the forces are greater in the eccentric mode, it seems that there is some neural inhibition, and it may be difficult to fully activate the muscles during eccentric actions (Westing et al 1990).…”

Section: Discussionsupporting

confidence: 84%

“…Although maximal eccentric force is higher than maximal concentric force (e.g., Doss and Karpovich 1965;Komi 1973;Westing et al 1990), there is evidence that in maximal eccentric actions the muscles may not be utilized to their full capacity (e.g., Westing et al 1990). The occurrence of a reduction in the amplitude of the average electromyogram (aEMG) observed during a single maximal eccentric action towards the end of the motion, but not during concentric action would support the concept of inhibition, as suggested by Westing et al (1990).…”

Section: Introductionmentioning

confidence: 99%

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EMG power spectrum and features of the superimposed M-wave during voluntary eccentric and concentric actions at different activation levels

2002

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Muscle fiber conduction velocity (CV) may be affected by the level of voluntary activation and by the diameter of the fiber. Both the frequency component of the electromyography (EMG) power spectrum, such the as median frequency (MF) or mean power frequency, and the duration of muscle compound action potential to single supramaximal electrical impulse (maximal M-wave) may be related to CV. The aim of the present study was to examine how changes in the activation level in lengthening and in shortening conditions would affect the EMG power spectrum during voluntary effort, and compare them to changes in M-wave shape in similar conditions. Ten male subjects performed eccentric and concentric knee extensions at force levels of 40%, 60%, 80% and 100% of maximal eccentric and concentric knee extension force (maximum voluntary contraction, MVC) at an angular velocity of 2 rad.s(-1). In order to measure the M-wave at each force level and in a relaxed condition, a supramaximal electrical stimulus was given to the femoral nerve. The surface EMG was recorded from the vastus lateralis, vastus medialis, and rectus femoris muscles, and the average EMG (aEMG) and MF were calculated. The results show that although the absolute force was greater, the aEMG was generally lower in eccentric as compared to concentric actions at all of the force levels tested. Although the aEMG increased as force increased, no consistent differences were observed in the amplitude of the maximal M-wave in any of the conditions, or in the duration of the M-wave between eccentric and concentric actions. However, as the force level increased the duration of the M-wave decreased significantly ( P<0.01) for both eccentric and concentric actions. On average, no major differences were observed in MF between eccentric and concentric actions or between the force levels in either type of contraction, although rather large variations were observed throughout the motions. In voluntary situations, the recruitment of fast motor units with higher muscle fiber CVs and the increased firing rate of the active units increases the muscle fiber CV as the activation level increases. Even though in conditions of supramaximal electrical nerve stimulation all motor units should be activated simultaneously, the duration of the M-wave in the present study decreased as the force level increased. Possible candidates for the change in the CV may be increased activation of the Na(+)/K(+) pump resulting from the activity in the muscle preceding the electrical stimulation and/or changes in the muscle fiber length between different force levels.

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Section: Discussionsupporting

confidence: 84%

Section: Introductionmentioning

confidence: 99%

EMG power spectrum and features of the superimposed M-wave during voluntary eccentric and concentric actions at different activation levels

2002

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“…When maximal voluntary eccentric force is compared with separately measured maximal voluntary isometric force at the corresponding joint angle, the isometric force is usually lower than the eccentric one (e.g. Asmussen et al 1965;Doss and Karpovich 1965;Komi 1973;Griffin 1987), although in some situations it may also be the opposite (Komi et al 2000;Singh and Karpovich 1966;Spurway et al 2000;Seger and Thorstenson 2000;Westing et al 1988). The later could be due to neural inhibition that has been suggested to occur during maximal voluntary eccentric action (Seger and Thorstenson 2000;Westing et al 1990) and therefore subjects have difficulties to maintain high eccentric force level throughout the motion.…”

Section: Introductionmentioning

confidence: 99%

Maximal force during eccentric and isometric actions at different elbow angles

2006

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The purpose of this study was to examine a course of force potentiation and/or inhibition during maximal voluntary eccentric action. Maximal voluntary force (MVC) of elbow flexion of ten healthy male volunteers was measured during isometric and isokinetic eccentric action starting from 80 degrees or 110 degrees and ending at 140 degrees elbow angle. Surface EMG was recorded from biceps brachii (BB) and brachioradialis (BR) muscles. Maximal voluntary eccentric force during the first 10 degrees of the movement was higher (P<0.001) than the maximal voluntary isometric preactivation force both in 80 degrees and in 110 degrees starting position at all three velocities (1, 2, and 4 rad s(-1)). The relative force potentiation was velocity dependent being smallest at the lowest stretching speed (P<0.01). Average EMG (aEMG) of BB and BR decreased as the joint angle increased both in eccentric and in isometric actions but the decrease in aEMG towards extension was somewhat higher in eccentric actions as compared to isometric. It was concluded that the force measured during the first 10 degrees of eccentric contraction always exceeded the maximal voluntary isometric preactivation force regardless of the joint angle or of the movement velocity. When maximal voluntary preactivation preceded the stretch, the relative force potentiation seemed to be greater at higher stretching velocities (velocity dependent) while at lower preactivation levels, the velocity dependence was not observed. Decreased muscle activation and lower maximal voluntary force towards the end of the movement suggested inhibition during maximal voluntary eccentric actions.

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“…The increase in strength is proportional to the amount of overload as measured by the relative force developed and the number of muscle actions performed during conditioning (17). Because greater maximum force can be developed during maximal eccentric (Ecc) muscle actions than during concentric (Con) or isometric muscle actions (6), it has been suggested that heavy-resistance training using Ecc muscle actions may be more effective than training using Con or isometric muscle actions in increasing strength (3,7,13).…”

mentioning

confidence: 99%

“…On the other hand, other studies have found substantial muscle hypertrophy after Con training on an isokinetic or accommodating resistance device (19,31,34) and no difference between Con training and training including Ecc muscle actions when Ecc training involved development of greater (3) or the same (22) force. In theory, because force development is greater (6,24) but neural activation is the same (24) or less (41) in maximal Ecc compared with Con muscle actions, greater strength changes after maximal Ecc compared with Con training should be explained by greater muscle hypertrophy or a combination of greater hypertrophy and neural activation. Because muscle dimensions are the same regardless of test mode, test-mode differences in strength changes after Ecc and Con training should be accounted for by differences in neural activation.…”

mentioning

confidence: 99%

Effects of concentric and eccentric training on muscle strength, cross-sectional area, and neural activation

Higbie

Cureton

Warren

et al. 1996

Journal of Applied Physiology

379

283

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Higbie, Elizabeth J., Kirk J. Cureton, Gordon L. Warren III, and Barry M. Prior. Effects of concentric and eccentric training on muscle strength, cross-sectional area, and neural activation. J. Appl. Physiol. 81(5): 2173-2181, 1996.-We compared the effects of concentric (Con) and eccentric (Ecc) isokinetic training on quadriceps muscle strength, cross-sectional area, and neural activation. Women (age 20.0 6 0.5 yr) randomly assigned to Con training (CTG; n 5 16), Ecc training (ETG; n 5 19), and control (CG; n 5 19) groups were tested before and after 10 wk of unilateral Con or Ecc knee-extension training. Average torque measured during Con and Ecc maximal voluntary knee extensions increased 18.4 and 12.8% for CTG, 6.8 and 36.2% for ETG, and 4.7 and 21.7% for CG, respectively. Increases by CTG and ETG were greater than for CG (P , 0.05). For CTG, the increase was greater when measured with Con than with Ecc testing. For ETG, the increase was greater when measured with Ecc than with Con testing. The increase by ETG with Ecc testing was greater than the increase by CTG with Con testing. Corresponding changes in the integrated voltage from an electromyogram measured during strength testing were 21.7 and 20.0% for CTG, 7.1 and 16.7% for ETG, and 28.0 and 29.1% for CG. Quadriceps cross-sectional area measured by magnetic resonance imaging (sum of 7 slices) increased more in ETG (6.6%) than in CTG (5.0%) (P , 0.05). We conclude that Ecc is more effective than Con isokinetic training for developing strength in Ecc isokinetic muscle actions and that Con is more effective than Ecc isokinetic training for developing strength in Con isokinetic muscle actions. Gains in strength consequent to Con and Ecc training are highly dependent on the muscle action used for training and testing. Muscle hypertrophy and neural adaptations contribute to strength increases consequent to both Con and Ecc training. electromyography; isokinetic muscle actions; muscle hypertrophy; training specificity; quadriceps muscle; women IT IS WELL ESTABLISHED that the primary stimulus for increasing the maximal force that can be exerted in a given movement (strength) is the repeated development of force by skeletal muscles at levels above those encountered in everyday activities (17). The increase in strength is proportional to the amount of overload as measured by the relative force developed and the number of muscle actions performed during conditioning (17). Because greater maximum force can be developed during maximal eccentric (Ecc) muscle actions than during concentric (Con) or isometric muscle actions (6), it has been suggested that heavy-resistance training using Ecc muscle actions may be more effective than training using Con or isometric muscle actions in increasing strength (3,7,13).Studies comparing the effectiveness of Ecc and Con muscle actions in increasing muscular strength have been equivocal (3, 4, 7-9, 18, 20-22, 24, 26, 40, 43). Different training protocols and methods of assessment have contributed to different outcomes. In studies ...

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A comparison of concentric, eccentric, and isometric strength of elbow flexors

Cited by 95 publications

References 0 publications

EMG power spectrum and features of the superimposed M-wave during voluntary eccentric and concentric actions at different activation levels

EMG power spectrum and features of the superimposed M-wave during voluntary eccentric and concentric actions at different activation levels

Maximal force during eccentric and isometric actions at different elbow angles

Effects of concentric and eccentric training on muscle strength, cross-sectional area, and neural activation

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