Comparison between manual aiming control and sex in different task constraints

AIMS: This study aimed to investigate the comparison between sex and manual aiming control in different cognitive and motor constraints of the task. METHODS: Eighty-four right-handed participants (42 women) performed 110 trials of a manual aiming task with a non-inking pen on a digitizing tablet. The aiming task required four different conditions of execution. The control condition appeared on the computer screen in 70% of the trials, and the other three conditions, (a) distractor, (b) inhibition of response and (c) higher index of difficulty, each appeared in 10% of the trials. RESULTS: Compared with women, men produced shorter movement and response times, as well as higher peak velocity in the control and distractor conditions. When the index of difficulty of the task increased, men produced only higher peak velocity. Women produced more corrective movements to achieve the target only in the control condition. CONCLUSION: Our results corroborate those of previous studies that indicate sex-specific response strategies when the sensory motor system is challenged by different task constraints.(AU)

The effect of on-line correction on stiffness of human upper limb during goal-directed movements / 医用生物力学

Objective To study the relationship between on-line correction and stiffness of the upper limb during human movements, so as to improve the measurement accuracy of stiffness and to assess the on-line correction capability. Methods Five kinds of upper limb goal-directed movements in a horizontal plane were designed. The stiffness values at 5 different positions, i.e. in the early period, early to mid period, mid period, mid to late period and late period separately during the movements with sudden perturbation were measured to investigate the regular pattern of human hand stiffness influenced by such on-line correction, as well as the relationship between the movement accuracy and hand stiffness. Results The stiffness was always varying during the movements, and the variation of the stiffness would influence the movement error. On-line correction during the movements could induce an increase in the value of stiffness amplitude, especially at the position in late period of the movement. However, no significant linkage was found between the change of stiffness and the occurrence time or content of on-line correction. Conclusions On-line correction plays an important role in goal-directed movements. Considering that on-line correction may cause a change in the amplitude of the stiffness, the on-line correction function of patients can be more accurately assessed by measuring stiffness value in specific experiments, combined with other medical diagnosis methods in clinic.