Kyung-Tae Yoo

The effect of various dual task training methods with gait on the balance and gait of patients with chronic stroke.

[Purpose] This study examined the effects of various dual task gait training methods (motor dual task gait training, cognitive dual task gait training, and motor and cognitive dual task gait training) on the balance and gait abilities of chronic stroke patients. [Subjects and Methods] Thirty-three outpatients performed dual task gait training for 30 minutes per day, three times a week, for eight weeks from June to August, 2012. Balance ability was measured pre-and posttest using the stability test index, the weight distribution index, the functional reach test, the timed up and go test, and the four square step test. Gait ability was measured by the 10 m walk test and a 6 min walk test before and after the training. The paired t-test was used to compare measurements before and after training within each group, and ANOVA was used to compare measurements before and after training among the groups. [Results] Comparisons within each group indicated significant differences in all variables between before and after the training in all three groups. Comparison between the groups showed that the greatest improvements were seen in all tests, except for the timed up and go test, following motor and cognitive dual task gait training. [Conclusion] In a real walking environment, the motor and cognitive dual task gait training was more effective at improving the balance and gait abilities of chronic stroke patients than either the motor dual task gait training or the cognitive dual task gait training alone.

Effect of isotonic and isokinetic exercise on muscle activity and balance of the ankle joint

[Purpose] This study was performed to examine how the balance of lower limbs and the muscle activities of the tibialis anterior (TA), the medial gastrocnemius (GCM), and the peroneus longus (PL) are influenced by isotonic and isokinetic exercise of the ankle joint. [Subjects] The subjects of this study were healthy adults (n=20), and they were divided into two groups (isotonic=10, isokinetic=10). [Methods] Isotonic group performed 3 sets of 10 contractions at 50% of MVIC and Isokinetic group performed 3 sets of 60°/sec. Muscle activity was measured by EMG and balance was measured by one-leg standing test. [Results] For muscle activity, a main effect of group was found in the non-dominant TA, and the dominant TA, GCM and PL. For balance, a main effect of time was found in both groups for the sway area measured support was provided by the non-dominant side. [Conclusion] In terms of muscle activity, the two groups showed a significant difference, and the isokinetic group showed higher muscle activities. In terms of balance, there was a significant difference between the pre-test and the post-test. The results of this study may help in the selection of exercises for physical therapy, because they show that muscle activity and balance vary according to the type of exercise.

Effects of shoe type on lower extremity muscle activity during treadmill walking

[Purpose] The purpose of this study was to analyze the effects of different shoe types on lower extremity muscle activity in healthy young women by using electromyography. [Subjects and Methods] Fifteen healthy young women in their 20s were included in this single-group repeated measures study. The subjects were divided into three groups: Converse sneakers, rain boots, and combat boots. The subjects walked on a treadmill at 4 km/h for 30 min, during which six muscles were examined using electromyography: the rectus femoris, vastus medialis, semimembranosus, tibialis anterior, peroneus longus, and medial head of the gastrocnemius. Between switching shoe types, a 24-h rest period was instated to prevent the fatigue effect from treadmill walking. [Results] One-way analysis of variance used to compare electromyography results among the three groups showed that the main effect of group differed significantly for the vastus medialis. Vastus medialis activity was higher in the rain boots group than the Converse sneakers group, and it was higher in the combat boots group than rain boots group. [Conclusion] Shoe type affects lower extremity muscle activity. Our findings may help individuals choose the ideal shoes for daily walking.

The effects of stabilization exercises using a sling and stretching on the range of motion and cervical alignment of straight neck patients

[Purpose] The purpose of this study was to assess how stretching exercise training and sling exercise training for stabilization influences the cervical spine angles and cervical range of motion of straight neck patients. [Subjects and Methods] Twenty straight neck patients were selected as subjects and they were randomly divided into two groups, the stretching and sling stabilization exercise groups which 60 minutes of exercise three times a week for 6weeks. All the subjects in each of the two respective study groups received an X-ray and had their cervical range of motion measured, both before and after the exercise. [Results] When differences in the cervical spine angle between the pre- and the post-test were checked, it was found that only the stretching exercise group showed statistically significant decreases in the craniovertebral angle and the cranial rotation angle. When differences in the range of motion between pre- and post-test were checked, the sling stabilization exercise group showed a significant change in flexion, right rotation, left lateral bending, right lateral bending, and the stretching exercise group showed a significant change in left rotation, left lateral bending, and right lateral bending. [Conclusion] These results indicate that both types of exercises are effective at improving the cervical range of motion of straight neck patients, and that the stretching exercise was more effective than the sling stabilization exercise at improving cervical spine angles.

Effects of different types of exercise on muscle activity and balance control.

[Purpose] This study analyzed the effects of isotonic, isokinetic, and isometric exercises of ankle joint muscles on lower extremity muscle activity and balance control. [Subjects and Methods] The subjects were 30 healthy adults (15 males) in their 20s who were randomly assigned to three different exercise method groups of 10 people each. The isokinetic exercise group performed three sets at an angular velocity of 60°/sec, including a single rest period after every set of 10 repetitions. The isometric exercise group performed three sets consisting of three 15 repetitions of a 15-second exercise followed by a 5-second rest. [Results] Multivariate analysis of variance revealed that depending on the exercise method, the non-dominant tibialis anterior, gastrocnemius muscle, and peroneus longus showed significant differences in muscle activity for weight-bearing non-dominant sides; when the dominant side was weight-bearing, the dominant gastrocnemius and peroneus longus showed significant differences in muscle activity; and the non-dominant and dominant sides showed significant differences in balance control depending on the duration of support in the area. [Conclusion] Muscle fatigue from the three exercise methods produced a decline in muscle activity and balance control; due to the fatigue before exercise, the side that did not perform the exercises was affected.

An analysis of the activity and muscle fatigue of the muscles around the neck under the three most frequent postures while using a smartphone

[Purpose] The purpose of this study was to identify changes in the activity and fatigue of the splenius capitis and upper trapezius muscles, which are agonists to the muscles supporting the head, under the three postures most frequently adopted while using a smartphone. [Subjects and Methods] The subjects were 15 college students in their 20s. They formed a single group and had to adopt three different postures (maximum bending, middle bending, and neutral). While the 15 subjects maintained the postures, muscle activity and fatigue were measured using surface electromyography. [Results] Comparison of the muscle fatigue caused by each posture showed statistically significant differences for the right splenius capitis, left splenius capitis, and left upper trapezius muscles. In addition, maintaining the maximum bending posture while using a smartphone resulted in higher levels of fatigue in the right splenius capitis, left splenius capitis, and left upper trapezius muscles compared with those for the middle bending posture. [Conclusion] Therefore, this study suggests that individuals should bend their neck slightly when using a smartphone, rather than bending it too much, or keep their neck straight to reduce fatigue of the cervical erector muscles.

Effects of Mannose on Pathogenesis of Acanthamoeba castellanii

Acanthamoeba spp. are single-celled protozoan organisms that are widely distributed in the environment. In this study, to understand functional roles of a mannose-binding protein (MBP), Acanthamoeba castellanii was treated with methyl-alpha-D-mannopyranoside (mannose), and adhesion and cytotoxicity of the amoeba were analyzed. In addition, to understand the association of MBP for amoeba phagocytosis, phagocytosis assay was analyzed using non-pathogenic bacterium, Escherichia coli K12. Amoebae treated with mannose for 20 cycles exhibited larger vacuoles occupying the most area of the amoebic cytoplasm in comparison with the control group amoebae and glucose-treated amoebae. Mannose-selected amoebae exhibited lower levels of binding to Chinese hamster ovary (CHO) cells. Exogenous mannose inhibited >50% inhibition of amoebae (control group) binding to CHO cells. Moreover, exogenous mannose inhibited amoebae (i.e., man-treated) binding to CHO cells by <15%. Mannose-selected amoebae exhibited significantly decreased cytotoxicity to CHO cells compared with the control group amoebae, 25.1% vs 92.1%. In phagocytic assay, mannose-selected amoebae exhibited significant decreases in bacterial uptake in comparison with the control group, 0.019% vs 0.03% (P<0.05). Taken together, it is suggested that mannose-selected A. castellanii trophozoites should be severely damaged and do not well interact with a target cell via a lectin of MBP.

The effects of open and closed kinetic chain exercises on the static and dynamic balance of the ankle joints in young healthy women

[Purpose] The purpose of the present study was to analyze the effects of open kinetic chain and closed kinetic chain exercises on the static and dynamic balance of ankle joints in young healthy women. [Subjects and Methods] Twenty women in their 20s were randomly assigned to two groups of ten women each: an open kinetic chain exercise group and a closed kinetic chain exercise group. Each group performed five sets of exercises three times per week for four weeks. Exercise intensity was increased once after two weeks. The subjects’ Romberg’s test results and their limits of stability were measured to evaluate their static and dynamic balance. The data were analyzed using a two-way repeated measures analysis of variance test. [Results] In the results of Romberg’s test, the main effect of the time showed a significant difference in the trace length with eyes closed (Effect size: d=0.97). In the result of limits of stability, the interaction effect showed a significant difference in the backward, and the main effect of the group showed a significant difference in the forward. [Conclusion] The open kinetic chain and closed kinetic chain exercises both improved the balance of the subjects. The closed kinetic chain exercise was more effective at improving the dynamic balance of young healthy women than the open kinetic chain exercise.

The effects of the length of rain boots on balance during treadmill walking

[Purpose] Effects of muscle fatigue on lower-extremity balance were evaluated in 12 healthy young women in their 20s while they walked on a treadmill wearing rain boots of different lengths. [Methods] The rain boots were divided into three groups based on the shaft length (Long, Middle, Short). Romberg’s test was applied and limits of stability were measured before and after treadmill walking. [Results] Romberg’s test showed a significant main effect for time. There were significant differences between the center of gravity area, length, and velocity when the eyes were open and the center of gravity length, velocity, and length/cm2 when the eyes were closed. Changes in the limits of stability also showed a significant main effect of time. There were significant differences in pre-test and post-test values in the left, right, forward, and total directions. [Conclusion] It was found that muscle fatigue in the lower extremities generated by walking in rain boots affected the joints and the adjuster muscles, depending on shaft lengths. Compensation due to visual feedback and the length of the boot shaft affected movement of the distal joints, resulting in a reduced ability to balance.

The effects of shoulder stabilization exercises and pectoralis minor stretching on balance and maximal shoulder muscle strength of healthy young adults with round shoulder posture

[Purpose] The purpose of this study was to analyze the effects of pectoralis minor stretching and shoulder strengthening with an elastic band on balance and maximal shoulder muscle strength in young adults with rounded shoulder posture. [Subjects and Methods] Nineteen subjects with rounded shoulder posture were randomly divided into 2 groups: a shoulder stabilization exercise group and a stretching exercise group. The groups performed each exercise for 40 minutes, 3 times a week, for 4 weeks. Static balance (eyes open and closed), dynamic balance (the limits of stability in 4 directions) and shoulder muscle strength in 5 directions were measure before and after the exercises. [Results] The stretching exercise demonstrated a significant difference between the pre- and post-exercise in the static balance with eyes closed and extension and horizontal abduction strength while the stabilization exercise demonstrated significant difference in the left and right directions between the pre- and post-exercise of the dynamic balance and flexion strength. The stabilization exercise demonstrated significant differences shown in the flexion between the pre- and post-test. [Conclusion] The shoulder stabilization and stretching exercises improved the static balance, dynamic balance, and muscle strength.