Comparison of force and timing control in periodic isometric leg extension.

Background: In daily life and sports activities, the regulation of muscle force and timing is often not controlled independently, rather the appropriate amount of force is controlled simultaneously with appropriate timing. However, which of the two variables, force or timing, is more difficult to control remains unclear.

Objective: We aimed to investigate the difficulty in the accurate control of force and timing, simultaneously.

The difference in hemodynamic responses between dominant and non-dominant hands during muscle contraction and relaxation: An fNIRS study.

The present study used functional near-infrared spectroscopy (fNIRS), and investigated the differences in neural activation of ipsi- or contralateral hemispheres between right dominant and left non-dominant hands among right-handed subjects using consecutive motor tasks with muscle contraction and relaxation. The subjects performed tasks under four conditions: (1) right hand up (R-Up), (2) left hand up (L-Up), (3) right hand down (R-Down), and (4) left hand down (L-Down). The peak amplitude of oxy-Hb was significantly larger at the contralateral than ipsilateral hemisphere in the premotor area (PM) under the R-Up condition, and no significant differences were observed between contra- and ipsilateral hemispheres under the L-Up condition.

Remote effects on corticospinal excitability during motor execution and motor imagery.

We investigated the remote effect on corticospinal excitability of resting left and right hand muscles during motor execution and motor imagery when performing left or right foot plantar flexion. Fifteen right-handed subjects performed two conditions with three tasks: Condition (Motor Execution (ME) vs. Motor Imagery (MI)): Task (Control, Ipsilateral, and Contralateral).

Force Control Characteristics for Generation and Relaxation in the Lower Limb.

We investigated the characteristics for force generation and relaxation using graded isometric contractions of the knee extensors. Participants performed the following tasks as quickly and accurately as possible. For the force generation task, force was increased from 0% to 20%, 40% and 60% of the maximal voluntary force (MVF).

Control Strategies for Accurate Force Generation and Relaxation.

Characteristics and motor strategies for force generation and force relaxation were examined using graded tasks during isometric force control. Ten female college students (M age = 20.2 yr.