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Aim Reaction times of the hip abductor were reported to be longer in elderly women than in elderly men, and this was suggested to be related to mediolateral balance performance. The aim of the present study was to investigate the effects of age and gender on the reaction performance of ankle muscles, which have predominant roles in anterioposterior balance control. Methods A total of 40 elderly subjects and 40 young subjects (even number of men and women) carried out a series of isometric plantarflexions and dorsiflexions, as forcefully and quickly as possible, in response to auditory stimulus. Surface electromyogram at the dorsiflexor and plantarflexor were recorded, together with foot plantar force. Premotor time, motor time and total reaction time derived from the experimental data were compared between age groups and genders by two-way anova. Results Both dorsiflexor and plantarflexor showed similar reaction performance. Premotor time increased with age with no gender difference. Motor time increased with age in women and not in men, resulting in longer motor time in elderly women than in elderly men. Total reaction time was dominated by premotor time, so that it was longer in the elderly with no gender difference. Conclusion Although age-related elongation of motor time was greater in women, total reaction time was not different between the genders. This may be related to no gender difference in anterioposterior balance performance. Geriatr Gerontol Int 2014; 14: 94–99.

A number of strength parameters were investigated in a group of subjects with chronic anterior cruciate ligament deficiency; The response of subjects' hamstring muscles to a perturbation on an isokinetic dynamometer was fractionated into the premotor and motor times. Rate of force development in the 75 ms following the perturbation was also measured. The functional ability of the subjects was examined using the Noyes knee rating system. The results showed that the motor time was significantly correlated with the rate of force development and functional ability of the subjects. The ratio of hamstring to quadriceps torque recorded at peak and 30° flexion during isokinetic muscle work at 180°/s was also investigated. No significant relationship was observed between these ratios and functional ability. These findings indicate that factors other than peak hamstring muscle torque may be important to the level of functional ability attained by people with chronic anterior cruciate ligament deficiency.

[Purpose] The aim of this study was to investigate the change in electromechanical reaction times (EMG-RT) of hip flexion of younger persons after neuromuscular joint facilitation (NJF) treatment. [Subjects] The subjects were 39 healthy young people, who were divided into two groups: a NJF group and a proprioceptive neuromuscular facilitation (PNF) group. The NJF group consisted of 16 subjects (7 males, 9 females), and the PNF group consisted of 23 subjects (10 males, 13 females). [Methods] Participants in the NJF group received NJF treatment. We measured the EMG-RT, the premotor time (PMT) and the motor time (MT) during hip flexion movement before and after the intervention in both groups. [Results] There were no significant differences among the results of the PNF group. For the NJF group, there were significant differences in PMT and EMG-RT after NJF treatment. [Conclusion] These results suggest that there is an immediate effect of NJF intervention on electromechanical reaction times of hip flexion.

An experiment was conducted to examine the effects of time uncertainty and instructed muscle tension on the reaction time of elbow flexion. Twenty-two right-handed subjects were asked to respond to an audio stimulus by flexing their right elbow under four conditions (2 time uncertainty × 2 instructed muscle tension). Electromyograms (EMGs) were recorded from the biceps and triceps on the subject's right side. Reaction time was divided into premotor time and motor time, based on the difference between the EMG and elbow flexion response. Analysis of reaction time showed that the effects of time uncertainty and instructed muscle tension were additive. Time uncertainty affected premotor time only, and instructed muscle tension affected motor time only. These results are discussed in terms of the assumption that premotor time is a reflection of the central nervous system and motor time is a reflection to the peripheral muscle system.

Single oral doses of lofepramine (140 mg), maprotiline (100 mg), and placebo were administered in a randomized three-way crossover design with 1 week wash-out between administrations to 12 healthy male volunteers. Before, and 1, and 3 h post-administration a battery of performance tests was administered which included a digit-matching paradigm and a reaction test separating recognition and motor time. In contrast to maprotiline, lofepramine did not impair speed and accuracy of cognitive performance.