Force and EMG power spectrum during eccentric and concentric actions

Komi, Paavo V.; Linnamo, Vesa; Silventoinen, Pertti; Sillanpaa, M.

doi:10.1097/00005768-200010000-00015

Cited by 152 publications

(134 citation statements)

References 31 publications

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“…Chan et al, 2001]. The observed variations in electromechanical delay performance are likely to reflect the influence of joint angle on the degree of myofillament overlap [McComas, 1996], the discharge properties of the motoneurons and the capability for neural activation [Komi et al, 2000] and the compliance characteristics of the 265 musculo-tendinous complex [Muraoka et al, 2004]. While it's not possible to quantify the relative effects of each of these processes in the current study, under most circumstances the majority of the EMD is determined by the time required to stretch the series elastic component (SEC) [Zhou et al, 1998;Granata et al, 2000;Kubo et al, 2000;Muraoka et al, 2004].…”

Section: 4 Discussionmentioning

confidence: 99%

“…Altered neural activation of the quadriceps at extreme and mid-range joint positions has been reported with corresponding changes to volitional performance [Komi et al, 2000;Babault et al, 2003;Desbrosses et al, 2006]. Although it is not possible from the current data 280 to estimate the relative contributions of the various influential processes, it may be plausible that the relative differences in evoked and volitional performances at altered joint positions might be determined by inherent differences in patterns of activation of the motor units (Maffiuletti, 2010), and which might be further mediated by joint position-specific and inhibitory processes that modulate access to the full quota of large high threshold motor units 285 under voluntary conditions [Tsuji and Nakamura, 1998;Zhou et al, 1998].…”

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confidence: 99%

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Joint angle affects volitional and magnetically-evoked neuromuscular performance differentially

Minshull

Rees²,

Gleeson

2011

Journal of Electromyography and Kinesiology

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This study examined the volitional and magnetically-evoked neuromuscular performance of the quadriceps femoris at functional knee joint angles adjacent to full extension. Indices of volitional and magnetically-evoked neuromuscular performance (N= 15 healthy males; 23.5 ± 2.9 years; 71.5 ± 5.4 kg; 176.5 ± 5.5 cm) were obtained at 25°; 35° and 45° of knee 30 flexion. Results showed that volitional and magnetically-evoked peak force (PF V ; PTFE, respectively) and electromechanical delay (EMD V ; EMD E , respectively) were enhanced by increased knee flexion. However, greater relative improvements in volitional compared to evoked indices of neuromuscular performance were observed with increasing flexion from 25° to 45° (e.g. EMD V ; EMD E : 36% vs. 11% improvement, respectively; F [2) i 4 ] = 6.8; p < 35 0.05). There were no significant correlations between EMD V and EMD E or PF V and PTF E , respectively at analogous joint positions. These findings suggest that the extent of the relative differential between volitional and evoked neuromuscular performance capabilities is joint angle-specific and not correlated with performance capabilities at adjacent angles, but tends to be smaller with increased flexion. As such, effective prediction of volitional 40 from evoked performance capabilities at both analogous and adjacent knee joint positions would lack robustness.

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Section: 4 Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Joint angle affects volitional and magnetically-evoked neuromuscular performance differentially

Minshull

Rees²,

Gleeson

2011

Journal of Electromyography and Kinesiology

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“…It is known that the blood pressure response during exercise has relationships with exercise intensity, duration and active muscle mass. 32,33 It is also known that although ECC includes less active muscle mass than CON [34][35][36][37] its exerted muscle strength is higher than CON. 16,31 Therefore, it might be thought that the active muscle mass in CON increases more than in ECC and that the accompanying significant vasopressor response increases the load on blood vessels.…”

Section: Discussionmentioning

confidence: 99%

Effects of eccentric and concentric resistance training on arterial stiffness

2006

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It has been suggested that resistance training (RT) increases arterial stiffness. The purpose of the present study was to clarify the effect of eccentric RT (ERT) and concentric RT (CRT) on arterial stiffness in female adults by an interventional study. In total, 29 healthy female subjects were randomly assigned to either the ERT group (n ¼ 10), CRT group (n ¼ 10) or sedentary (SED) group (n ¼ 9). The ERT and CRT groups performed resistance training three times a week for 8 weeks. We determined brachial blood pressure, brachial-ankle pulse wave velocity (baPWV), carotid artery intimamedial thickness (IMT) and carotid arterial lumen diameter before and after training and after detraining.The before-training baPWV did not differ significantly among the three groups. After 8 weeks of RT, arterial stiffness in the CRT group was increased compared with the ERT and SED group (Po0.05). However, brachial blood pressure, baPWV, carotid IMT and carotid lumen diameter in the ERT and CRT groups were unchanged by RT for 8 weeks. Consequently, it was clarified that arterial stiffness was not changed by ERT for 8 weeks. This suggests that ERT may be effective as an exercise prescription for middle-aged and elderly adults.

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“…Three lines of evidence support this point of view. First, when individuals perform maximal isokinetic actions, EMG amplitude recorded with surface electrodes is often less during lengthening contractions than during shortening contractions performed at the same speed (Aagaard et al, 2000;Amiridis et al, 1996;Kellis and Baltzopoulos, 1998;Komi et al, 2000;Tesch et al, 1990;Westing et al, 1991); the difference is even greater when the lengthening contraction is not preceded by a maximal isometric contraction (Komi et al, 2000). Second, the level of voluntary activation assessed by superimposing a single stimulus or a brief train of electrical pulses over the muscle or its motor nerve during the force plateau of a MVC is often, but not always (Babault et al, 2001), depressed during lengthening contractions (Amiridis et al, 1996;Beltman et al, 2004;Westing et al, 1990).…”

Section: Muscle Activation During Maximal Contractionmentioning

confidence: 99%

Neural control of lengthening contractions

Duchateau

Enoka

2016

Journal of Experimental Biology

171

181

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A number of studies over the last few decades have established that the control strategy employed by the nervous system during lengthening (eccentric) differs from those used during shortening (concentric) and isometric contractions. The purpose of this review is to summarize current knowledge on the neural control of lengthening contractions. After a brief discussion of methodological issues that can confound the comparison between lengthening and shortening actions, the review provides evidence that untrained individuals are usually unable to fully activate their muscles during a maximal lengthening contraction and that motor unit activity during submaximal lengthening actions differs from that during shortening actions. Contrary to common knowledge, however, more recent studies have found that the recruitment order of motor units is similar during submaximal shortening and lengthening contractions, but that discharge rate is systematically lower during lengthening actions. Subsequently, the review examines the mechanisms responsible for the specific control of maximal and submaximal lengthening contractions as reported by recent studies on the modulation of cortical and spinal excitability. As similar modulation has been observed regardless of contraction intensity, it appears that spinal and corticospinal excitability are reduced during lengthening compared with shortening and isometric contractions. Nonetheless, the modulation observed during lengthening contractions is mainly attributable to inhibition at the spinal level.

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Force and EMG power spectrum during eccentric and concentric actions

Cited by 152 publications

References 31 publications

Joint angle affects volitional and magnetically-evoked neuromuscular performance differentially

Joint angle affects volitional and magnetically-evoked neuromuscular performance differentially

Effects of eccentric and concentric resistance training on arterial stiffness

Neural control of lengthening contractions

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