• PNF and Movement
• /
• v.15 no.3
• /
• pp.311-316
• /
• 2017

Purpose: Flatfeet are one of the risk factors of foot dysfunction and postural imbalance. The purpose of this study was to compare the limitation of stability (LOS) for the center of gravity (COG) between flatfeet and neutral feet on stable and unstable support surfaces. Methods: The study included 26 healthy, adult male participants: 14 with normal feet and 12 with flatfeet. The subjects were asked to incline the trunk maximumly to the left, right, anterior, and posterior directions and were asked to keep their feet on the floor with the knee extension. The subjects had 30 seconds of rest time between the tasks. The LOS (anterior, posterior, left, right) of COG was measured by Balance Trainer (BT4, Hur-labs, Tampere, Finland). An independent t- test was used to compare the LOS of COG between flatfeet and normal feet on stable and unstable support surfaces, respectively. Results: The LOS of the flatfeet group was generally decreased on stable support surfaces as compared to that of neutral feet, but it was not significantly different (p>0.05), while the LOS of the flatfeet group was significantly decreased compared to that of neutral feet on unstable support surfaces (p<0.05). Conclusion: This study suggested that the LOS of individuals with flatfeet may be decreased on unstable support surfaces and the postural balance of the flatfeet group may easily be disturbed on an unstable support surface.

• PNF and Movement
• /
• v.16 no.2
• /
• pp.249-257
• /
• 2018

Purpose: This study aimed to explore the effects of additional trunk exercises on an unstable surface on the balance and walking ability of individuals with chronic stroke. Methods: Sixteen patients with chronic stroke participated in this study. The participants were randomly assigned to two groups: experimental group (n=8) and control group (n=8). All the participants underwent a typical physical therapy program for 30 min a day. Moreover, the experimental group participated in a 30 min trunk exercise program on an unstable surface, whereas the control group participated in a 30 min trunk exercise program on a stable surface. Both groups performed the exercises five times a week for three weeks. The Berg Balance Scale (BBS) was used to measure changes in balance. The gait variables were measured using the GAITRite system (CIR System Inc., Clifton, NJ, USA) to examine changes in walking ability. Results: Both groups showed a significant intragroup improvement in balance, gait speed, cadence, stride length, and double support period (p<0.05). In the intergroup comparisons after the intervention, the experimental group showed significant improvements over the control group in balance, gait speed, cadence, stride length, and double support period (p<0.05). Conclusion: This study applied additional trunk exercises on an unstable surface to chronic stroke patients, and the results showed a significant improvement in the patients' balance and walking abilities. Therefore, trunk exercise on an unstable surface may be applicable as an intervention method to improve the balance and walking ability of chronic stroke patients.

• Physical Therapy Korea
• /
• v.19 no.1
• /
• pp.28-36
• /
• 2012

This study used an unstable platform to change the support surface type and position of both lower limbs in order to determine changes in weight distribution and muscle including the vastus medialis, tibialis anterior, lateral hamstring, and lateral gastrocnemius of both lower limbs were evaluated during knee joint flexing and extending in a semi-squat movement in 32 hemiplegic patients. The support surface conditions applied to the lower limbs were divided into four categories: condition 1 had a stable platform for both lower limbs; condition 2 had an unstable platform for the non-hemiplegic side and a stable platform for the hemiplegic side; condition 3 had a stable platform for the non-hemiplegic side and an unstable platform for the hemiplegic side; and condition 4 had an unstable platform for both sides. The normalized EMG activity levels of muscles and weight bearing ratio of both sides in the four surface conditions were compared using repeated measures ANOVA. A significant increase was found in the weight support distribution for the hemiplegic side in flexing and extending sessions in condition 2 compared to the other conditions (p<.05). A statistically significant decrease in significant decrease in asymmetrical weight bearing in flexing and extending sessions was observed for condition 2 compared to the other conditions (p<.05). A similar significant decrease was found in differences in muscular activity for both lower limbs in condition 2 (p<.05). The muscular activity of the hemiplegic side, based on the support surface for each muscle showed a significantly greater increase in condition 2 (p<.05). An unstable platform for the non-hemiplegic side and a stable platform for the hemiplegic side therefore increased symmetry in terms of the weight support distribution rate and muscle activity of lower limbs in hemiplegic patients. The problem of postural control due to asymmetry in hemiplegic patients should be further studied with the aim of developing continuous effects of functional training based on the type and position of the support surfaces and functional improvement.

• The Journal of Korean Physical Therapy
• /
• v.24 no.5
• /
• pp.300-305
• /
• 2012

Purpose: This study examined the muscle activity of the trunk muscles during weight shifting exercises on a stable and unstable surface. Methods: Ten healthy young subjects (4 males, 6 females) with no medical history of lower-extremity or lumbar spine disease were enrolled in this study. The muscle activity was recorded using surface electromyography (EMG) electrodes from the both sides of the external obliques and erector spinae muscles. Results: The EMG activities of the both rectus abdominalis, both external obliques and erector spinae muscles were significantly higher when the weight shifting exercise was performed on a firm surface than when a balance pad with a balance ball was used. In weight shifting exercises, the EMG activity of the contralateral external obliques and erector spinae muscles was significantly higher than that of the ipsilateral external obliques and erector spinae muscles under all three support surface conditions. Conclusion: Performing weight shifting exercise using an unstable surface is a useful method for facilitating the trunk-muscle strength and trunk stability.

• Journal of The Korean Society of Integrative Medicine
• /
• v.9 no.1
• /
• pp.1-11
• /
• 2021

Purpose : The purpose of this study was to investigate the effect of single limb stance exercise according to the support surface on dynamic balance ability and abdominal muscle thickness. Methods : We recruited 28 healthy subjects in this study. Subjects were assigned to 2 groups by matching method. The control group was 5 males and 9 females, and single limb stance exercise was performed on the stable support surface. The experimental group consisted of 6 males and 8 females, and trained to stand on the unstable support. During the single limb stance exercise, the dominant foot was set as the foot that appeared numerically through the exercise of the dynamic balance meter (Biorescue). Single limb stance exercise along the supporting surface was maintained for 15 seconds and then rested for 15 seconds. It was repeated 5 times. Particularly, the balance exercise on the unstable support surface was sufficiently practiced. Independent t test was performed for comparison between groups. Paired t test was performed to compare before and after each group. Results : There was no difference between the control group and the experimental group in the comparison of dynamic balance ability (p>.05). However, there were significant differences before and after exercise in both the control and experimental groups (p<.05). Similarly, in the comparison of abdominal muscle thickness, there was a significant difference within each group, especially internal oblique and transverse abdominis (p<.05), and no difference between groups (p>.05). Conclusion : Based on these results, although there was no difference between the groups, in the experimental group, numerical increase in dynamic balance ability and abdominal muscle thickness was confirmed. Therefore, single limb stance exercise on the unstable support surfaces activates core muscles and has a positive effect on dynamic balancing ability.

• Journal of Korean Physical Therapy Science
• /
• v.25 no.3
• /
• pp.25-31
• /
• 2018

Background: The purpose of this study was to find out how changes in knee angles in stable and unstable support surfaces affect the muscle thickness of core muscles. Methods: The subjects of this study were 25 male adult. Each knee angle of 120, 90 and 60 degrees, they were performed bridge exercise on the stabilized surface and on the unstable support surface using TOGU, and measured the muscle thickness of the external and internal oblique muscle and the abdominal muscles through ultrasound images. Results: There was no significant difference between the thickness of the rectus abdominis and the internal oblique muscle depending on the support surface and the knee joint bending angles. However, there was a significant difference between the external oblique muscle and the transverse abdominis muscle by knee joint flexion angle. Conclusion: While the muscle thickness of the core muscle was not significantly affected by each support surface during the bridge exercise, there were significant changes in the core muscle as a result of changes in knee angle.

• The Journal of Korean Physical Therapy
• /
• v.33 no.6
• /
• pp.265-271
• /
• 2021

Purpose: We aimed to analyze the reliability of the test for choice stepping reaction time (CSRT) under an unstable surface and determine whether there were differences in CSRT between support surface conditions (stable vs. unstable conditions) and between age groups (young adults vs. community-dwelling older adults). Methods: Twenty healthy community-dwelling older adults and twenty young adults performed the stepping task under an unstable condition over two visits. The mean of the two trials measured for each visit was used for the analysis. The test-retest reliability was analyzed using intra-class correlation coefficient (ICC) with a 95% confidence interval, standard error of measurement (SEM), and minimal detectable change (MDC). Differences in CSRT between support surface conditions and age groups were analyzed using the independent t-test with Bonferroni correction. Results: Excellent consistency was observed for ICC >0.90 in both groups. Moreover, the SEM and MDC values of the CSRT in older and young adults were 0.03 and 0.09 and 0.01 and 0.04, respectively. There was a significant difference in the CSRT between the age groups under stable (p<0.001) and unstable conditions (p<0.001). Conclusion: The findings demonstrated that the test for CSRT under an unstable condition had reliable results in both groups. Although older adults demonstrated longer reaction times than younger adults in all surface conditions, increasing the balance control demand by implementing a choice stepping task concomitant with a balance task had no influence on the reaction time in both age groups.

• The Journal of Korean Physical Therapy
• /
• v.23 no.2
• /
• pp.7-15
• /
• 2011

Purpose: We investigated the relationship between the muscle activity and kinematic variables of the upper extremity during a push-up task on stable and unstable surfaces. Methods: We recruited 15 healthy subjects. Subjects completed the push-up task on stable and unstable surfaces. Surface electromyograms were recorded from the serratus anterior, upper trapezius, latissimus dorsi, infraspinatus to monitor changes in muscle activity. Markers for kinematic changes of elbow flexion, shoulder extension, shoulder retraction and scapular adduction were attached at C7, the T7 spinous process, both acromions, the scapula superior and inferior angle, the humerus lateral epicondyle, and the ulnar styloid process. Correlation coefficients between muscle activity and kinematic variables were analyzed by SPSS for Windows, version 15.0. Results: On the unstable surface, elbow flexion and shoulder extension increased with increasing muscle activity of serratus anterior, upper trapezius and infraspinatus. On the stable surface, shoulder retraction decreased with increasing muscle activity of serratus anterior and infraspinatus. Scapular adduction decreased with all types of increasing muscle activity, regardless of the support surface. Conclusion: Correlations between muscle activity and kinematic variables were observed on stable and unstable surfaces during a push-up task, while correlations between right and left variables were not clear. These finding suggest that it may be used to develop a rehabilitation program which could be effective in improving shoulder function in patients with shoulder problems.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
• /
• v.29 no.3
• /
• pp.1-11
• /
• 2023

Background: The aim of this study was to compare the effects of squat training on an unstable support surface with different knee flexion angles on the balance ability of normal adults balance ability. Methods: 41 university students in their 20s attending N University in Cheonan, Chungcheongnam-do were divided into a 45-degree knee-bending squat training group and a 90-degree knee-bending squat training group. The groups trained on an unstable support surface 20 minutes per day, 3 times a week, for a total of 4 weeks. Results: Changes in static balance ability were not significant within and between the groups for both the sway distance and sway area in the eyes open and eyes closed states (p<.05). The changes in dynamic balance ability were significant in the forward, leftward, and rightward angles in both groups at the limit of stability (p<.05), but not significant in the backward angle (p>.05), and the comparison between groups was not significant (p>.05). Conclusion: No significant difference between static balance-related variables within and between the groups was found. Significant changes in dynamic balance-related variables within the groups were found but not between the groups. Therefore, in future studies, it is considered necessary to study various ages and differentiated intervention periods, such as young adults and the population of elderly people, with sufficient intervention periods to affect balance ability.

• PNF and Movement
• /
• v.20 no.1
• /
• pp.67-72
• /
• 2022

Purpose: The aim of this study was to compare trunk and lower extremity muscle activity during deadlift on stable - and unstable surfaces. Methods: Twenty healthy men participated in this study. The participants performed deadlift exercise on both a stable surface and an unstable surface. During the deadlift, the activities of the trunk and lower extremity muscle were collected by using electromyography. Results: The results showed that the electromyographic activity of the gluteus maximus significantly increased during deadlift on an unstable surface compared to on a stable surface (p <0.05). However, in the electromyographic activities of the rectus femoris, biceps femoris, and erector spinae, there were no significant differences (p >0.05). Conclusion: The finding that the electromyographic activity of the gluteus maximus increases significantly during deadlift on an unstable surface compared to stable one could be used to develop an efficient exercise program.