The relationship of motor unit size, firing rate and force

Conwit, Robin; Stashuk, Daniel W.; Tracy, Brian; McHugh, Megan; Brown, William F.; Metter, E. J.

doi:10.1016/s1388-2457(99)00054-1

Cited by 84 publications

(66 citation statements)

References 12 publications

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“…They found, using (H 2 15 O) positron emission tomography, a logarithmic increase in regional cerebral blood flow in a number of motor areas, including the primary sensorimotor cortex, as force increased during dynamic index finger flexion. With regard to motor unit evaluation during force exertion, Conwit et al (15) reported that there was a relationship between motor unit size (recruitment), which was estimated by the size of surface motor unit action potential, and force generation (5-100% knee extension MVC) of the VM muscle (r ϭ 0.82, P Ͻ 0.001). Finally, Kukulka and Clamann (29) demonstrated that motor unit recruitment in a large muscle such as the biceps brachii continues over the entire force range.…”

Section: Discussionmentioning

confidence: 99%

“…The firing rate of motoneurons is also important for voluntary force production (15). According to Conwit et al (15), firing rate of active motoneurons in the knee extensors (VM) increases with force increments Ͼ30% of MVC, thereby augmenting force.…”

Section: Discussionmentioning

confidence: 99%

“…Descending command from the central nervous system regulates motor unit recruitment and firing rate so that the desired motor task can proceed (8)(9)(10). Motor unit recruitment is mainly used to increase force in large muscles, such as the quadriceps femoris (QF) and the biceps brachii (15,29). In the QF, it has been demonstrated that recruitment of musculus rectus femoris (RF) does not necessarily coincide with that of the three m. vasti during repetitive isometric or isokinetic knee extension exercise (KEE) (6,7,20,28,42).…”

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confidence: 99%

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Vastus lateralis fatigue alters recruitment of musculus quadriceps femoris in humans

Akima

Foley

Prior³

et al. 2002

Journal of Applied Physiology

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. Vastus lateralis fatigue alters recruitment of musculus quadriceps femoris in humans. J Appl Physiol 92: 679-684, 2002; 10.1152/ japplphysiol.00267.2001.-This study tested the hypothesis that fatigue of a single member of musculus quadriceps femoris (QF) would alter use of the other three muscles during knee extension exercise (KEE). Six men performed KEE with the left QF at a load equal to 50% of the 4 ϫ 10 repetitions maximum. Subsequently, electromyostimulation (EMS), intended to stimulate and fatigue the left m. vastus lateralis (VL), was applied for 30 min. Immediately after EMS, subjects repeated the KEE. Transverse relaxation time (T2)-weighted magnetic resonance images were taken before and after each bout of KEE and at 3 and 30 min of EMS to assess use and stimulation, respectively, of the QF. T2 of each of the QF muscles was increased 8-13% after the first KEE. During EMS, T2 increased (P Ͻ 0.05) even more in VL (10%), whereas it decreased (P Ͻ 0.05) to pre-KEE levels in m. vastus medials (VM) and m. rectus femoris (RF). The VL and, to some extent, the m. vastus intermedius were stimulated, whereas the VM and RF were not, thereby recovering from the first bout of KEE. Isometric torque, initially 30% of maximal voluntary, was reduced to 13% at 3 min and 7% at 30 min. T2 was greater (P Ͻ 0.05) after the second than the first bout of KEE, especially the increase for the VM and RF. These results suggest that subjects were able to perform the second bout with little contribution of the VL by greater use of the other QF muscles. The simplest explanation is increased central command to the QF such that the intended act could be accomplished despite acute fatigue of one of its synergists.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

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Vastus lateralis fatigue alters recruitment of musculus quadriceps femoris in humans

Akima

Foley

Prior³

et al. 2002

Journal of Applied Physiology

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“…However, with the decomposition techniques, it is possible to analyze the firing rate at higher efforts. 39,141,147 At 30% of MVC or higher force levels, the motor unit firing rate is increased in patients with myopathy. 45,172 More studies are needed to obtain precise information on sensitivity and specificity of the methods.…”

Section: Analysis Of Motor Unit Firing Ratementioning

confidence: 99%

The utility of interference pattern analysis

Fuglsang-Frederiksen

2000

Muscle Nerve

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“…1 Architecture of the biological motor system. mented using the following three assumptions [5]: the activation of the neurons follows the size principle of motor neurons, the recruitment of more motor neurons is linear, and the firing rate of each neuron remains constant.…”

Section: Methodsmentioning

confidence: 99%

A Bio-Inspired Cognitive Architecture of the Motor System for Virtual Creatures

Madrigal

Torres

Ramos

2014

IEICE Trans. Inf. & Syst.

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SUMMARYIn this paper we present a cognitive architecture inspired on the biological functioning of the motor system in humans. To test the model, we built a robotic hand with a Lego Mindstorms TM kit. Then, through communication between the architecture and the robotic hand, the latter was able to perform the movement of the fingers, which therefore allowed it to perform grasping of some objects. In order to obtain these results, the architecture performed a conversion of the activation of motor neuron pools into specific degrees of servo motor movement. In this case, servo motors acted as muscles, and degrees of movement as exerted muscle force. Finally, this architecture will be integrated with high-order cognitive functions towards getting automatic motor commands generation, through planning and decision making mechanisms. key words: cognitive architecture, artificial intelligence, robotic hand

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The relationship of motor unit size, firing rate and force

Cited by 84 publications

References 12 publications

Vastus lateralis fatigue alters recruitment of musculus quadriceps femoris in humans

Vastus lateralis fatigue alters recruitment of musculus quadriceps femoris in humans

The utility of interference pattern analysis

A Bio-Inspired Cognitive Architecture of the Motor System for Virtual Creatures

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