Abstract. [Purpose] This study investigated the effect of physical training with visual feedback and mental training with motor imagery on balance control ability.[Subjects] Twenty-one healthy adults (male/ female: 7/14, mean age: 19.8 ± 0.1 years) with no history of neurological or orthopedic problems were enrolled in this study. The subjects were randomly divided into a physical training group (PTG), a mental training group (MTG), and a control group (CG).[Methods] PTG and MTG performed a dynamic balance task with physical and mental training, respectively, in a 30-minute training session, 5 days a week for 3 weeks. The CG did not receive any training. The outcomes of postural balance were evaluated in terms of the performance time and sway length measured by a force platform. [Results] In the baseline test, the three groups showed similar demographic data, performance time, and sway length. The PTG and MTG showed a significant decrease in performance time, but neither group showed any significant change in sway length. There was no significant difference in the CG.[Conclusion] Our findings indicate that physical balance training with visual feedback as well as mental balance training with motor imagery is effective. Therefore, mental training could contribute to improving dynamic balance ability in a cost-effective home-based training program.

We demonstrated the exact location of the somatotopic area of the corticospinal tract in the internal capsule. Ten healthy subjects participated in this study. We used the imaging technique that combines functional magnetic resonance imaging and diffusion tensor tractography. In order to reduce erroneous elements while image processing, we used the probabilistic tracking algorithm and brain normalization method. Our results showed that hand fibers were located anteromedial to foot fibers, and the separation angle between them was 45.00–78.69°. In conclusion, we confirmed the relative location of hand and foot fibers and the separation angle in the internal capsule. These data are useful information for neuroscience researchers.

Abstract. [Purpose] This study examined whether motor imagery leads to a decrease in the temporal process in terms of the onset of muscle activation and reaction time according to acquisition of motor skills in a serial reaction time (SRT) task.[Subjects] Forty one healthy, right-handed subjects with no history of neurological, orthopedic, or psychiatric disorders were enrolled in this study. The subjects were assigned randomly to the motor training group (n=13), motor imagery group (n=14), and control group (n=11).[Methods] After six visual stimuli, the subjects were instructed to move or press a moveable arm/button according to the corresponding stimuli. However, the motor imagery group performed the task without actual movement in the same task paradigm. The kinetic parameters (i.e. muscle activation and movement initiation) were analyzed before and after the training/controlled session over three consecutive days with two repetitions per day for each group.[Results] After motor skill acquisition, the motor training group and motor imagery group showed a significant decrease in processing times between the visual stimuli and two predetermined onsets, which consisted of the onset of muscular activation and reaction time. However, there were no significant changes in the control group.[Conclusion] The decrease in processing time through motor imagery can be attributed to the rapid onset of muscle activation and movement initiation, which might be induced by neuromuscular adaptation in the motor performance phase. Furthermore, we assumed that imagining the performance of a motor task could contributes to improving the motor performance in motor sequential learning.

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Purpose: This study sought to identify the effects of an insole applied for the flexible flat-foot condition on dynamic balance and ankle muscle activities during the Y-balance test (YBT). Methods: Thirteen flexible flat-footed adults and an equal number of normal-footed adults were enrolled. The dynamic balance of the subjects was measured using the YBT, which is a reach test. While they were reaching forward with their foot, the percentage maximum voluntary isometric contraction (MVIC) of the tibialis anterior, peroneus longus and medial and lateral gastrocnemius were measured and analyzed. The flat-footed group then applied the ready-made insoles and underwent the YBT again. A comparison of the distance and muscle activity was conducted using YBT, not only between the flat-footed and control group, but also between the flat-footed group before and after the application of the insole. Results: Between the groups, the anterior reach distance in the flat-footed group was significantly lower, but there were no significant differences observed in the posteromedial and posterolateral directions. With the insole, the reach distance of the flat-footed group was significantly increased in the anterior and posterolateral direction compared to the control group. With the insole, the lateral gastrocnemius activity significantly decreased compared to trials without the insole in the flat-footed group, but there were no significant differences in the other muscles. Conclusion:The insole for flat-footed subjects can maintain the medial arch of the foot, and it may help enhance functional and mechanical dynamic balance in people with flat feet.