Jintae Han

Effects of forward head posture on forced vital capacity and respiratory muscles activity

[Purpose] This study investigated the effects of forward head posture on forced vital capacity and deep breathing. [Subjects] Twenty-six subjects, divided into the two groups (normal and forward head posture groups), participated in this study. [Methods] Forced vital capacity and forced expiratory volume in 1 second were measured using respiratory function instrumentation that met the American Thoracic Society’s recommendation for diagnostic spirometry. Accessory respiratory muscle activity during deep breathing was measured by electromyography. A Mann-Whitney test was used to compare the measure variables between the normal and forward head posture group. [Results] Forced vital capacity and forced expiratory volume in 1 second were significantly lower in the forward head posture group than in the normal group. Accessory respiratory muscle activity was also lower in the forward head posture group than in the normal group. In particular, the sternocleidomastoid and pectoralis major activity of the forward head posture group was significantly lower than that of normal group. Activities of the other muscles were generally decreased with forward head posture, but were not significantly different between the two groups. [Conclusion] These results indicate that forward head posture could reduce vital capacity, possibly because of weakness or disharmony of the accessory respiratory muscles.

Effect of Muscle Vibration on Postural Balance of Parkinson's Diseases Patients in Bipedal Quiet Standing

[Purpose] The purpose of this study was to investigate the effect of muscle vibration applied to the lower extremities on static postural balance of patients with Parkinson’s disease (PD). [Subjects] Seven subjects with Parkinson’s disease participated in this study. [Methods] The oscillators of vibration were attached to the muscle bellies of the tibialis anterior, gastrocnemius, biceps femoris, and rectus femoris on both sides of the lower extremities with adhesive tape. A vibration frequency of 60 Hz was used to induce static postural reactions. Subjects’ center of pressure (COP) sway and peak ground reaction force (GRF) were measured with their eyes open with and without vibration. COP sway and peak GRF (Fx, Fy, Fz) were measured using a force plate (AMTI, Newton, USA), which provides x, y and z coordinates of body movement. [Results] The area of COP sway with vibration was significantly smaller than that with no vibration, but the length of COP sway showed no difference between two conditions. Peak medial-lateral maximum force (Fy) with vibration was significantly higher than that with no vibration, but peak anterior-posterior force (Fx) and peak vertical force (Fz) showed no differences. [Conclusion] These results suggest that vibration applied to the lower extremities can help PD patients control postural balance during quiet standing.

Comparisons of changes in the two-point discrimination test following muscle fatigue in healthy adults.

[Purpose] This study aimed to examine the effects of muscle fatigue on skin sensation by looking at changes in two-point discrimination (2PD) after inducing muscle fatigue. [Subjects] Thirty-four young and healthy adults with no pathological symptoms (17 males; 17 females) participated in this study. [Methods] Continuous isometric contraction was applied to the upper and lower extremities with an intensity of 50% of the maximal muscle strength to trigger muscle fatigue, and then the 2PD test was conducted on the 3 cm medial area of the elbow and 5 cm area of the knee bone. [Results] After muscle fatigue was induced, the 2PD distance significantly increased in the upper and lower extremities of both males and females. Before triggering muscle fatigue, the 2PD distance was longer in males than females, but after causing muscle fatigue, there was no difference between males and females. The increase in 2PD distance after the experiment was more significant in females than males. [Conclusion] Muscle fatigue has an effect of reducing the skin’s sensory faculty by increasing the 2PD distance in the skin. There is a difference in the response of the skin according to body area and gender; therefore, caution is needed to avoid triggering fatigue during exercise.

Kinematic Analysis of Lower Extremities during Stairs and Ramp Climbing with Older Adults

The purpose of this study was to investigate the kinemaitc gait parameter of lower extremities with different gait conditions(level walking, stairs, ramp) in old adults. Fourteen healthy older adults participated in this study and kinematic data were measured using 3D motion analysis system(Vicon, Oxford Metrics, England). Statistical analysis was used one-way ANOVA to know the difference of lower extremities angle at each gait phase with a different gait conditions. In sagittal plane, pelvic anterior tilt increased in stairs and ramp climbing and hip and knee flexion increased in stairs climbing but ankle dorsiflexion increased in ramp climbing. In frontal plane, pelvic was up in stairs and hip abduction and adduction more changed in stairs climbing than level walking. Knee varus and ankle inversion increased in stair climbing. In horizontal plane, pelvic internal rotation increased in stairs and ramp climbing and knee internal rotation increased in stairs climbing but ankle external rotation increased in stairs climbing. This results was shown that the stairs and ramp climbing changed the kinematic gait parameters of lower extremities in healthy old adults.

Effect of Muscle Vibration on Spatiotemporal Gait Parameters in Patients with Parkinson’s Disease

[Purpose] The purpose of this study was to investigate the effect of muscle vibration in the lower extremities in patients with Parkinson’s disease (PD) during walking. [Subjects] Nine patients with PD participated in this study and were tested with and without vibration (vibration at 60 Hz). [Methods] Eight oscillators of vibration were attached to the muscle bellies (tibialis anterior, gastrocnemius, biceps femoris, and rectus femoris) on both sides of the lower extremities with adhesive tape in this study. Spatiotemporal gait parameters were measured using a motion analysis system. [Results] Stride length and walking speed with vibration were significantly increased compared with those without vibration in PD patients. [Conclusion] These results suggest that the application of vibration to lower extremity muscles in patients with PD may improve the parkinsonian gait pattern.

Effects of foot position of the nonparetic side during sit-to-stand training on postural balance in patients with stroke

[Purpose] We aimed to investigate postural balance after sit-to-stand (STS) training with different nonparetic foot positions in stroke patients. [Subjects] Thirty-six subjects who experienced a stroke (21 males, 15 females) participated and were divided into the symmetric foot position (SYMM), asymmetric foot position (ASYM), and step foot (STEP) groups. [Methods] Each group performed repetitive sit-to-stand training 5 times a week for 6 weeks. The timed up-and-go test (TUG), functional reach test (FRT), and F-mat system correcting the anterior/posterior (A-P) and medial/lateral (M-L) distance of the center of pressure (COP) were used to measure the static and dynamic postural balance pre- and postintervention. ANCOVA was used to analyze differences among groups, and preintervention variables were used as covariates. [Results] The TUG, FRT, and A-P and M-L distance of the COP in the ASYM and STEP groups were significantly decreased after intervention compared with the SYMM group. All parameters in the STEP group were lower than those in the ASYM group, without a significant difference. [Conclusion] The asymmetric foot position during STS is a good intervention to improve the static and dynamic postural balance in stroke patients. Especially, using a step to change the foot position is effective in improving STS performance.

Effects of wearing ankle weight on knee joint repositioning sense in the elderly

[Purpose] To investigate the effects of different ankle weights on knee joint repositioning sense in elderly individuals. [Subjects and Methods] Twenty-one subjects were divided for assessment as follows: young (20–30 years, n=10) and elderly (60–70 years, n=11). Knee joint repositioning error was measured by asking the subjects to reposition the target angle of their knee joints while wearing different ankle weights (0%, 0.5%, 1%, and 1.5%) in an open kinetic chain. The Hawk Digital System (60 Hz; Motion Analysis, Santa Rosa, CA, USA) was used to measure knee joint repositioning error. Differences in knee joint repositioning error between the young and elderly groups according to ankle weight load were examined by using two-way mixed repeated-measures analysis of variance. [Results] The knee joint repositioning error was lower with than without ankle weights in both groups. The error value was lowest with the 1.0% weight, though not significantly. Knee joint repositioning error was significantly higher in the elderly under all the ankle weight conditions. [Conclusion] Knee joint repositioning sense can be improved in elderly individuals by wearing proper ankle weights. However, weights that are too heavy might disturb knee joint positioning sense.

The Effect of Motor Learning of Serial Reaction Time Task (SRTT) Through Action Observation on Mu Rhythm and Improvement of Behavior Abilities

Background The aim of this study was investigate whether an action observation would have an effect on the action that requires task understanding in humans. Methods Participants who met the criteria for this study (n = 36). To evaluate the performance, reaction time and performance accuracy, the stimulus scheduling software was employed. For the electroencephalogram, the equipment QEEG-8 was used. Results Concerning the reaction time of the groups of different learning methods a significant difference was found after the learning among the three groups. Regarding the accuracy among the groups of different learning methods, significant difference was found in the action performance accuracy among the three groups. The relative mu power during the SRTT implementation was compared in the CZ, C3 and C4 regions before, during, and after the learning for each group. In the CZ and C4 region, a significant difference was found in the action observation group. In the C3 and C4 region a significant difference was found in the actual practice group. Conclusions The result suggests that imitation and learning are involved even in the action that requires task understanding in humans. Keywords Accuracy; Mirror neuron system; Mu Rhythm; Reaction time; SRTT