STUDY DESIGN Lifting dynamics and electromyographic activity were evaluated using a biomechanical model of spinal equilibrium and stability to assess cost-benefit effects of antagonistic muscle cocontraction on the risk of stability failure. OBJECTIVES To evaluate whether increased biomechanical stability associated with antagonistic cocontraction was capable of stabilizing the related increa...

Cocontraction (the simultaneous activation of antagonist muscles around a joint) provides the nervous system with a way to adapt the mechanical properties of the limb to changing task requirements-both in statics and during movement. However, relatively little is known about the conditions under which the motor system modulates limb impedance through cocontraction. The goal of this study was to...

Cocontraction (the simultaneous activation of antagonist muscles around a joint) provides the nervous system with a way to adapt the mechanical properties of the limb to changing task requirements-both in statics and during movement. However relatively little is known about the conditions under which the motor system modulates limb impedance through cocontraction. The goal of this study was to ...

In this study, we investigated muscle cocontraction during a street dance movement task to provide evidence that the level of muscle cocontraction is associated with degree of proficiency in whole-body sensorimotor synchronization movement. Skilled street dancers and nondancers were required to synchronize a knee-bending movement in a standing position to a metronome beat. The dancer group show...

STUDY DESIGN Controlled laboratory study, cross-sectional data. OBJECTIVES To investigate isometric knee flexion and extension strength, failure of voluntary muscle activation, and antagonist cocontraction of subjects with knee osteoarthritis (OA) compared with age-matched asymptomatic control subjects. BACKGROUND Quadriceps weakness is a common impairment in individuals with knee OA. Disus...

Optimization of cocontraction of antagonistic muscles around the ankle joint has been shown to involve plastic changes in spinal and cortical neural circuitries. Such changes may explain the ability of elite ballet dancers to maintain a steady balance during various ballet postures. Here we investigated whether short-term cocontraction training in ballet dancers and nondancers leads to changes ...

It has been stated in the literature that static, nonlinear optimization approaches cannot predict coactivation of pairs of antagonistic muscles; however, numerical solutions of such approaches have predicted coactivation of pairs of one-joint and multijoint antagonists. Analytical support for either finding is not available in the literature for systems containing more than one degree of freed...

Efficient control of reciprocal activation and cocontraction of the muscles are critical to perform skillful actions with suitable force and impedance. However, it remains unclear how the brain controls force and impedance while recruiting the same set of muscles as actuators. Does control take place at the single muscle level leading to force and impedance, or are there higher-order centers de...

BACKGROUND The purpose of this study was to elucidate relationships between quadriceps and hamstrings voluntary muscle fatigue and upper motor lesion impairments in cerebral palsy in order to gain a better understanding of their contribution to the observed fatigue resistance. METHODS Seventeen ambulatory subjects with cerebral palsy (mean age: 17.0, SD=4.8 years) were recruited. Quantitative...

CONTEXT Sex differences in neuromuscular control of the lower extremity have been identified as a potential cause for the greater incidence of anterior cruciate ligament (ACL) injuries in female athletes compared with male athletes. Women tend to land in greater knee valgus with higher abduction loads than men. Because knee abduction loads increase ACL strain, the inability to minimize these lo...