Earticle

Purpose: This study examined the effects of different foot positions on gluteus maximus muscle activation, balance, and gait during fast-speed sit-to-stand training for stroke patients. Methods: Fifteen stroke patients participated in the study, and five patients each were assigned randomly to the AAU group, ABU group, or UBA group in fast-speed sit-to-stand training. The patients participated in this training five times for several weeks with three daily sets of 10 repetitions. The effects of the training were assessed by measuring the gluteus maximus muscle activation, balance ability, and gait speed. A Kruskal-Wallis one-way ANOVA and Dunn's post-hoc test were used to determine the statistical significance of the differences among the groups. Results: The ABU group showed significantly greater improvements in gluteus maximus muscle activation, balance, and gait ability after training compared to the measurements taken before training (p<0.05). Conclusion: Placing the affected foot behind the unaffected foot during sit-to-stand training may be more effective for stroke patients. This positioning should be incorporated into rehabilitation interventions to increase gluteus maximus activation, balance, and gait ability.

PURPOSE: This study was conducted to identify the effects of altering foot position on quadriceps femoris including vastus medialis obliques (VMO), vastus lateralis (VL) and rectus femoris (RF) activation during wall squat exercises. METHODS: All subjects (n = 15) were selected and randomly performed three kinds of wall squats: 1) GWS (General Wall Squat), 2) WSS1/4 (Wall Squat Short 1/4), and 3) WSS1/2 (Wall Squat Short 1/2). Each subject completed all three kinds of wall squatting exercises at three different times and recorded the muscle activity data of vastus medialis obliques, vastus lateralis and rectus femoris. RESULTS: Compared with GWS exercise, VMO and RF muscle activity significantly increased under WSS1/2 exercise (p < .05), while only RF muscle activity significantly increased under WSS1/4 exercise (p < .05). CONCLUSION: The results of the present study indicate that moving the foot toward the wall during wall squats has a positive effect on quadriceps activation. The exercise of wall squat short can not only be used as the lower limb muscle strengthening training for normal people, but also as the recovery training for patellofemoral pain syndrome patients in the rehabilitation stage. Besides, Anterior cruciate ligament patients can also try this exercise according to the advice of doctors and therapists.

Purpose: This study aimed to improve the asymmetrical weight-bearing ratio, by applying different repetitive sit-to-stand training methods to the paretic-side foot of hemiplegic patients, as well as to provide the necessary information for applying balance training with hemiplegic patients. Methods: The subjects were divided into two groups: a spontaneous foot group and an asymmetrical foot group. They all performed repetitive sit-to-stand training five times a week for a total of six weeks. The sit-to-standing movement was studied using standardized clinical tests. The Biodex Balance System, Time up and go test (TUG), 5 times sit-to-stand test (5XSST), and functional reach test (FRT) were used to measure the static and dynamic standing balance of the patients. Results: In the balance system measurement, the results for the overall index, ant-post index, med-lat index, fall risk index, 5XSST, and FRT after the training differed significantly between the comparison groups (p<0.05). In the evaluation of dynamic balance, the differences in TUG did not differ significantly between the comparison groups after the training (p>0.05). Conclusion: The study found that the asymmetrical group showed significant increases in static and dynamic balance in comparison to the spontaneous group after repetitive sit-to-stand training. Based on this result, it is clear that training in an asymmetrical position with the paretic foot back can increase the left-right stability limit and the anterior-posterior stability limit, thus improving balance control.

PURPOSE: This study was aim to the change of muscle activities of lower extremity and waist during lifting a small object on the floor according to different foot position of women in their twenties wearing a skirt. METHODS: 9 women in their twenties wearing a skirt were selected and were measured the muscle activities of medial gastrocnemius (MG), tibialis anterior (TA), vastus lateralis (VL) and iliocostalis (IC) when they lifted a small object on the floor. The two different foot position employed were "both feet posed straight side by side" (condition 1) and "both feet posed diagonally to 45 degree" (condition 2) used. The order of feet position was selected randomly and the subject took a rest for 30 min between tests to prevent muscle fatigue. We calculated the mean and standard deviation of muscle activities and used Mann-Whitney U test to compare the difference between the two foot positions with SPSS(IBM Korea) RESULTS: The muscle activity of condition 2 was greater than that of condition 1 in right side of TA, VL, and IC and left side of TA, VL, MG and IC. The right side of TA, VL and left side VL were significant difference between condition 1 and condition 2(p<.05). CONCLUSION: We suggest "both feet posed straight side by side" position is better if a woman wearing a skirt lift the small object and it will help prevent the low back and lower limb problems in the future.

Background: The MLA is supported by both the abductor hallucis (ABH) and the extrinsic muscles. Insufficient muscular support may lower the MLA when the body's weight is applied to the foot. The short foot exercise (SFE) is effective in increasing the height of the MLA for people with flat feet. Most of the research related to the SFE has simply evaluated the efficiency of the exercise using enhanced ABH electromyography (EMG) activation. Since the tibialis anterior (TA), peroneus longus (PER), and ABH are all involved in supporting the MLA, a new experiment design examining the EMG of the selected muscles during SFE should be applied to clarify its effect. Objects: Therefore, this study aimed to clarify the effect of the SFE in different ankle position on the MLA angle and the activation of both the intrinsic and extrinsic muscles and to determine the optimal position. Methods: 20 healthy subjects and 12 subjects with flat feet were recruited from Yonsei University. The surface EMG and camera were used to collect muscle activation amplitude of TA, PER, and ABH and to capture the image of MLA angle during SFE. The subjects performed the SFE while sitting in three different ankle positions-neutral (N), dorsiflexion (DF) at 30 degrees, and plantar flexion (PF) at 30 degrees. Results: ABH EMG amplitudes were significantly greater in N and DF than in PF (p<.05). Muscle activation ratio of TA to ABH was the lowest in PF (p<.05). MLA angle in both groups significantly decreased in PF (p<.01). The TA and ABH was activated at the highest level in DF. However, in PF, subjects significantly activated the ABH and PER with relatively low activation of TA. Conclusion: Therefore, researchers need to discuss which SFE condition most effectively use the arch support muscle for flat foot.

Background Obesity has been suggested as a social issue, but problems in the foot and ankle have not been clearly identified in people with obesity. Purpose To compare foot posture, joint position sense, dynamic balance ability, and plantar pressure in obesity group (OG) and normal weight group (NWG) Study design Cross-sectional study Methods This study included 52 adults (26 for OG and 26 for NWG). All subjects had their foot posture index-6 and joint position sense (20° of inversion, 20° of plantar flexion, 10° of eversion, and 10° of dorsiflexion) measured, as well as their dynamic balance ability using a dynamic balance test and plantar pressure of the medial forefoot during the dynamic balance test. These variables were compared between OG and NWG. Results OG showed significantly larger joint position sense error for eversion and increased plantar pressure of the medial forefoot during the dynamic balance test in the posteromedial direction. Significant differences were unobserved in other variables between the two groups. Conclusions Adults with obesity have deficits in joint position sense and increased plantar pressure of the medial forefoot.

Objective: Eversion of the foot is created with internal rotation of the shank, and inversion of the foot is created with external rotation of the shank. The purpose of the study was to investigate the effect of continuous changes in the angle of the subtalar joint on lower extremity alignments. Design: Cross-sectional study. Methods: Seventeen healthy young adult subjects recruited. The subjects were asked to stand up in a natural standing position on a footplate with eye open and equal weight on each foot for 10s in two different conditions: The right subtalar joint was everted continuously $0^{\circ}-20^{\circ}$ and in separate segments of $0^{\circ}$, $5^{\circ}$, $10^{\circ}$, $15^{\circ}$, $20^{\circ}$. The averages of three trials were used. The observation of the changes in the lower extremity was performed with the use of 3-dimensional motion analysis. For data analysis, the SPSS 18.0 software using paired t-test and repeated measures analysis of variance (ANOVA) was applied. Results: The angle was significantly increased at the horizontal rotation angle of the shank, thigh, and ankle without anterior rotation of the pelvis (p<0.05). The maximum horizontal rotation angle at the thigh on $20^{\circ}$ was $-4.52^{\circ}$ in static, and $-3.10^{\circ}$ in the dynamic conditions compared to $0^{\circ}$. Conclusions: Increased unilateral foot pronation, thigh, shank, ankle horizontal rotation variance was significantly effective. The observation of the changes in foot abduction with the use of a 3-dimensional motion analysis augmented in predicting the angle values of each segment of the lower extremity. In further studies, a comparison of the right and left subtalar joints need to be investigated.

Purpose: This study aimed to identify the exercise posture that most efficiently activates the scapular upward rotators among three positions. Methods: Participants were divided into three groups based on foot placement: the 100%, 150%, and 200% groups, with each group randomly assigned 30 participants. The 100% position involved placing the feet to support the wall with the forearm in the wall slide position, transitioning from a standing position. As for the exercise method, a wall slide exercise was performed up to 150˚ shoulder joint flexion, and scapular upward rotator muscle activity was measured during the 5 seconds of concentric contraction. Results: Serratus anterior muscle activity was measured at 46.91±5.96 in the 100% group, 66.97±6.40 in the 150% group, and 45.92±6.77 in the 200% group. A statistically significant difference was found between the 150% and 100% groups, as well as between the 150% and 200% groups (p<.05). No significant difference was observed between the 100% and 200% groups (p>.05). Additionally, no significant differences were found in upper or lower trapezius muscle activity across the three positions (p>.05). Conclusion: The highest serratus anterior muscle activity was observed in the 150% group, where the feet were positioned at the middle distance. Thus, performing the wall slide exercise at the 150% position is considered optimal for activating the serratus anterior muscle.

Purpose: The purpose of this study was to evaluate the electromyographic (EMG) activity of vastus medialis oblique (VMO) and vastus lateralis (VL) muscles on foot position and knee angle for hemiplegia patients. Methods: Ten stroke subjects (10 males) participated in the study. Subjects were all right-hemiplegic patients. All subjects did $0^{\circ},\;20^{\circ}$ and $40^{\circ}$ knee flexion while maintaining the foot in a neutral position, or at $30^{\circ}$ adduction or at $30^{\circ}$ abduction. Surface EMG data were collected for VMO and VL muscles on the non-hemiplegic side and hemiplegic side. Collected data were analyzed using two-way ANOVA. Results: VMO and VL activities for the non-hemiplegic and the hemiplegic sides were highest for $40^{\circ}$ knee flexion while maintaining the three foot positions. There were no significant differences in EMG activity of the VMO and VL muscles with different foot positions. There were significant differences between VMO and VL activity for knee flexion angle while maintaining the foot in neutral (p<0.05), at $30^{\circ}$ adduction (p<0.05), or at $30^{\circ}$ abduction (p<0.05). Conclusion: Foot position does not influence VMO and VL activities. But, knee flexion exercise in a closed chain can increase VMO and VL muscle activity for hemiplegic patients. In particular, VMO and VL activities for both the non-hemi side and the hemi side were highest for $40^{\circ}$ knee flexion.

An excessive Q-angle has been implicated in the development of knee injuries by altering the lower-extremity locomotion kinematics. The purpose of this study was performed to examine the correlation between the Q-angle and the CTA during pronation and supination of the foot in the standing status. The participants of this examination were 60 adult(30 men and 30 women) who had no orthopaedic and neurological impairment, aged between 20 and 40years. The foot tilt(FT1)is made of acrylic plate and the slope of the surface is altered as $0^{\circ}$ pronation$(10^{\circ},\;20^{\circ},\;30^{\circ})$ and supination $(10^{\circ},\;20^{\circ},\;30^{\circ})$. The results were as follows : 1. The result about the Q-angle and the CTA by comparing pronation and supination of the foot There was statistical significance difference in the left /right Q-angle and the left/right CTA with pronation and supination of the foot(P<0.05). 2. The result about correlation in the left /right lower-extremity There were positive correlation between the right Q-angle and the right CTA and negative correlation except the supination$(30^{\circ})$ between the left Q-angle and the left CTA.

본 연구의 목적은 세 종류의 양발 위치에 따른 주요 복부근육인 복직근, 외복사근, 대퇴직근의 근육 활동을 측정 함으로서 복부 근력 강화에 가장 효율적인 윗몸일으키기의 양발 위치를 파악하는데 있다. 이를 위해서 체육학과 남자 신입생 20명을 대상으로 세 종류(싯업 보드에 다리를 가까이 붙여 양발 거리가 0cm;Type A, 양발 거리가 20cm;Type B, 양발 거리가 30cm;Type C)의 양발 위치에 따른 윗몸일으키기 시 상복직부, 하복직부, 외복사근, 대퇴직근의 활동 차이를 EMG를 사용하여 살펴보았다. 또한 윗몸일으키기 시 세 종류의 양발 위치에 따른 근전도 값의 통계적인 유의차 에 대한 검증은 SPSS의 반복측정을 통한 일원분산분석을 유의수준 p<.05 수준에서 살펴보았다. 그 결과, Type B에서 상복직부, 하복직부, 외복사근, 대퇴직근의 최대 근부하율과 굴곡 시 평균 근부하율이 유의하게 높게 나타났으나 신전 시에는 상복직부, 외복사근에서 유의하게 높은 근육활동을 보였다. 평균 및 최대 근부하율이 높다는 것은 근육활동이 활발하다는 것을 의미하므로 본 연구에서 가장 높은 근육활동을 보인 양 발 위치가 20cm인 Type B로 양발을 고정시켜 윗몸일으키기를 실시했을 때 효율적인 복근강화를 가져올 수 있을 것으로 사료된다.

This purpose of this study was to investigate the effects of three different types of foot position on upper and lower rectus abdominals, external oblique, and rectus femoris muscle activities during sit-up exercise, and to find out the effective foot position of sit-up exercise for strengthening the abdominal muscles. Twenty male students who are attending the university majoring in the physical education were selected for subjects. To assess the myoelectrical activities of selected muscles, wireless electromyographic devices were used. Average and peak nEMG levels in three different type of foot position(two foot together;type A, two foot 20cm apart:Type B and two foot 30cm apart:Type C) during sit-up exercise were determined for each participant. And each variables were evaluated using a repeated one way ANOVA with significant level of p<.05. From that experiments, type B showed the significantly higher average and peak nEMG of upper and lower rectus abdominals, external oblique and rectus femoris muscle in flexed phase. But in extension phase it showed the significantly higher average nEMG of upper rectus abdominals and external oblique. The higher average and peak nEMG means the vigorous muscle activity during exercise. Therefore it is considered that sit-up exercise with Type B is suitable for strengthening the abdominal muscles.

Objective: To evaluate the effect of custom molded foot orthosis without heel lift in scoliosis patients who had different pelvic height caused by inequality of RCSPA (resting calcaneal stance position angle). Method: We retrospectively reviewed the medical data of all patients who had been prescribed custom molded foot orthosis without heel lift in our institution from 2005 to 2009 and chose 38 scoliosis patients with Cobb's angle (≥10o) and different pelvic height (≥5 mm) caused by inequality of RCSPA (≥2o). Radiologic findings of whole spine AP and RCSPA were measured pre and post treatment and compared. Results: Twenty two females and sixteen males were included in this study. Their mean age was 7.76±3.72 years. Their mean period of wearing orthosis was 14.11±3.25 months. Initial average Cobb's angle of 13.18±3.16o were reduced to 7.42±3.45o (p＜0.001). Initial difference of height between right and left iliac crest of 0.87±0.26 cm reduced to 0.55±0.28 cm (p＜0.01) and angle of pelvic inequality of 3.98±1.55o reduced to 2.54±1.27o (p＜0.05). Initial difference of RCSPA between right and left of 3.69±1.54o decreased to 1.69±1.54o (p＜0.01). Each parameter has significantly reduced 12 months after the wearing of the custom molded foot orthosis in scoliosis patients whose age was 9 or below, whose Cobb's angle at 15o or lower. Conclusion: The custom molded foot orthosis without heel lift was effective for scoliosis patients, who had different pelvic height caused by inequality of RCSPA. (J Korean Acad Rehab Med 2010; 34: 66-73)

Background: Short foot exercise (SFex) is often prescribed and performed in the sport and rehabilitation fields to strengthen intrinsic foot muscles. However, SFex is difficult to perform because of lack of feedback methods. Objects: The aim of this study was to compare the effects of SFex with and without electromyography (EMG) biofeedback on the medial longitudinal arch (MLA) of healthy individuals who maintained a static standing position. Methods: All participants (14 males and 12 females) were randomly divided into two groups (biofeedback and non-biofeedback groups). The EMG activity of the abductor hallucis (AbdH) and tibialis anterior (TA) and the MLA angle on the dominant leg side were measured with the participant in the standing position in the pre- and post-intervention conditions. The intervention session consisted of 15 minutes of SFex with (biofeedback group) or without (non-biofeedback group) EMG biofeedback. The groups were compared using two-way repeated measures analysis of variance. Results: The post-intervention activities of the AbdH muscle (p<.05) and the AbdH/TA ratio (p<.05) were significantly greater in the biofeedback group than in the non-biofeedback group. The activity of the TA (p<.05) and the MLA angle (p<.05) in the biofeedback group were significantly lower in the post-intervention condition than in the pre-intervention condition. Conclusion: The present findings demonstrate that the combination of SFex and EMG biofeedback can effectively facilitate the muscle activity of the AbdH and strengthen the medial longitudinal arch.

An excessive Q-angle has been implicated in the development of knee injuries by altering the lower-extremity locomotion kinematics. The purpose of this study was measured the Q-angle and the CTA when the foot moves pronation and supination of the foot in the standing status. The participants of this examination were 60 adult(30 men and 30 women) who had no orthopaedic and neurological impairment, aged between 20 and 40years. The foot tilt(FT 1)is made of acrylic plate and the slope of the suface is altered as $0^{\circ}$, pronation ($10^{\circ},20^{\circ},30^{\circ}$)and supination($10^{\circ},20^{\circ},30^{\circ}$). The results were as follows : 1. The result about the left/right Q-angle and the left/right CAT There was no statistical significant difference between the left and the right side of the Q-angle with different position of the foot(P > 0.05). While significant difference in the left CTA at the $0^{\circ}$, pronation($10^{\circ},20^{\circ},30^{\circ}$) and supination($10^{\circ},20^{\circ}$) has been observed(P < 0.05). 2. The result about the Q-angle and the CTA between male and female There was significant difference in the Q-angle between male and female with different position of the foot(P < 0.05). while significant different in the right CTA at the $0^{\circ}$ pronation ($20^{\circ}$)(P < 0.05), no significant difference in the left CTA have been observed(P > 0.05). 3. The result about correlation between the left/right Q-angle and the left/right CAT There was statistical significant positive correlation between the left/right Q-angle and the left/right CAT with the different position of the foot(P < 0.01).

The purpose of this study was to compare the balance ability at different foot positions using K A T 2000 (Berg, Inc, vista, CA.1994). Thirty (male 15, female 15) normal subjects participated in this study. All subjects were tested at a one leg position or a two leg position that were toe-in 25˚, toe-out 25˚, and 45˚. The starting position was where the subject crossed their arms across the chest and flexed knees slightily. The results of each test were displayed on a screen in a score format, which indicated balance index. These collected data were analyzed by using one way ANOVA, and t-test. The results of this study were as follows: When changing the angle of the foot in the one-foot and two-foot standing positions, there was no statistically significant difference, but the balance performance with the foot rotated by 25˚ was better than that with the foot rotated by 45˚. When changing the direction of the foot in the one-foot and two-foot standing positions, there was no statistically significant difference, but the balance performance with the foot rotated laterally was better - except for the case when the foot was medially rotated by 25˚ in the right-foot static standing position. When the feet were medially rotated by 25˚ in the two-foot static standing position, and were medially rotated by 25˚ and 45˚ in the one-foot static standing position, the balance performance of females was better than that of males. In this study, it was found that the balance performance of the subjects changed when the position of the foot was shifted on an unstable base of support. However, there was little correlation between balance performance and the height, weight and foot length of the subjects. It is necessary to conduct a follow-up study targeting various age groups and those with various diseases using an unstable platform or applying different physical or visual conditions, such as the length of the legs. Physical therapists need to consider the position of the foot in clinical settings for a better balance training or assessment.

The purpose of this study was to investigate the muscle activity of the lower extremity during driver swing in three-foot positions (Feet Open Stance, Feet Straight Stance, Lead Foot Open Stance). The electromyograms of gastrocnemius, tibialis anterior, and vastus lateralis during swing were measured and analyzed in three sections (take away - back swing, back swing - down swing, and down swing - follow swing). There was no significant difference in muscle activity according to foot position. Muscle activity according to phase was significantly higher in right gastrocnemius and tibialis anterior, and the left and right vastus lateralis in down swing - follow swing. In conclusion, the difference in muscle activity according to foot position is insignificant, and it is considered that the muscle activity to maintain the balance of the body increases toward the end of swing.

운동학 학술지, 2012, 14(2): 137-146. 뇌졸중 환자의 유병기간 및 발 위치에 따른 일어서기 동작의 특성. [서론] 이 연구의 목적 뇌졸중 환자의 유병기간과 발의 위치에 따른 일어서기 동작의 특성을 분석하는 것이다. 뇌졸중 환자의 움직임과 관련된 선행연구들은 환자들의 유병기간을 고려하지 않은 채 그 결과를 일반적인 뇌졸중 환자의 움직임 특성으로 정의한다. 발 위치의 변화는 유병기간이 상이한 뇌졸중 환자들의 일어서기 동작에 어떤 영향을 줄 것인가 하는 의문에서 본 연구가 시작되었다. [방법] 압력측정 장비와 근전도 장비를 이용하여 일어서기 동작 수행 시 양 하지의 피크 압력, 힘, 대퇴직근, 대퇴이두근, 전경골근, 가자미근의 활동이 분석되었다. 대상자들은 세 가지 조건의 발 위치에서 일어서기 동작을 수행하였다. 조건1) 양발 나란히 놓고 일어서기, 조건2) 환측발을 건측발 뒤에 두고 일어서기, 조건3) 건측발을 환측발 뒤에 두고 일어서기 등이다. [결과] 뇌졸중 유병기간이 12개월 미만인 대상자들은 환측발을 건측발 뒤에 두고 일어서기 수행 시 양발의 최대 피크 압력이 크게 나타났고, 환측과 건측의 수직력 차이가 가장 작게 나타났다. 환측발을 건측발 뒤에 두고 일어서기 수행 시 환측 대퇴사두근의 활동이 감소하였다. [결론] 환측발을 건측발 뒤에 두고 일어서기 동작을 수행하는 것이 뇌졸중 유병기간이 짧은 대상자들에게 도움이 되는 전략으로 사료된다. 또한 유병기간 3년 전·후의 뇌졸중 환자들의 일어서기 동작 시 근육의 건측과 환측의 활동패턴이 다르게 나타났다. 따라서 뇌졸중 환자의 움직임 연구 수행 시 유병기간이 고려되어야 할 것이다.

[INTRODUCTION] The purpose of this study was to investigate the characteristics of Sit-To-Stand(STS) movement in stroke patients according to the stroke onset time and foot positions, analyzing force, foot pressure, and muscle activities. Many studies which investigated the characteristics of movements have not considered stroke onset time in subjects. The foot positions may influence the STS in subjects who had different stroke onset time. [METHOD] Foot pressure, force, and the activities of four muscles(Rectus Femoris, Bicpes Femoris, Tibialis Anterior, & Soleus) were measured, using Novel emed-x systems and DELSYS Trigno Wireless system. Subjects performed STS movements in three foot conditions(con1: two foots are parallel, con2: paretic limb is placed posterior to non-paretic limb, & con3: non-pareitc limb is placed posterior to paretic limb). [RESULT] Subjects who suffered from stroke within 12 months showed the maximum value of peak pressure, the minimum value of difference in vertical force between paretic and non-pareatic limb, and decrease of Rectus Femoris at paretic limb in con2. [CONCLUSION] The strategy which is the paretic limb was placed posterior to the non-paretic limb might be a helpful method for acute stroke patients. Stroke onset time within/after three years had an effect on activities of muscles. Therefore, stroke onset time might be considered in the movement study.

In this paper, a dual foot (DF)-PDR system is proposed for the fusion of integration (IA)-based PDR systems independently applied on both shoes. The horizontal positions of the two shoes estimated from each PDR system are fused based on a particle filter. The proposed method bounds the position error even if the walking time increases without an additional sensor. The distribution of particles is a non-Gaussian distribution to express the lateral error due to systematic drift. Assuming that the shoe position is the pedestrian position, the multi-modal position distribution can be fused into one using the Gaussian sum. The fused pedestrian position is used as a measurement of each particle filter so that the position error is corrected. As a result, experimental results show that position of pedestrians can be effectively estimated by using only the inertial sensors attached to both shoes.