Earticle

Purpose: This study investigated the effects of visual feedback-based eccentric pulley training (EPT) on static and dynamic balance in patients with low back pain (LBP). Methods: A total of 54 participants were randomly divided into three groups: 18 in the visual feedback-based EPT (VF-EPT) group, 18 in the EPT group, and 18 in the eccentric training (ET) group. The VF-EPT group performed pulley eccentric training with visual feedback; the EPT group received pulley eccentric training without visual feedback; and the ET group performed eccentric training only, without visual feedback or a pulley. All groups trained for 30 minutes per session, three times per week for four weeks. Static balance was assessed using the Single-Leg Standing Test (SLST), and dynamic balance was assessed using the Star Excursion Balance Test (SEBT). Results: Balance ability improved significantly only in the VF-EPT group (p < 0.05), and significant between-group differences were also observed (p < 0.05). Conclusion: These results suggest that visual feedback-based eccentric pulley training may be effective in improving both static and dynamic balance in patients with LBP.

Purpose: In this study, we investigated the effects of visual feedback-based eccentric pulley training (EPT) on motion speed and pressure pain threshold (PPT) changes in patients with low back pain (LBP). Methods: Participants were randomly categorized into the visual feedback-based EPT (VF-EPT) group, EPT group, and the eccentric training (ET) group with 18 participants in each group. All participants underwent 30 min of training per session, thrice a week for 4 weeks. For evaluation of motion speed, participants underwent assessment of the motion speed of trunk rotation, squat and trunk rotation, single-leg deadlift, and seated lat pull-down motions. The PPT was measured for pain evaluation. Results: All groups showed statistically significant changes in motion speed (p<0.05); however, we observed no significant intergroup differences. PPT was statistically significant in the VF-EPT group (p<0.05), and we observed significant intergroup differences (p<0.05). Conclusion: This study highlights that visual feedback training can effectively improve motion speed and pain control in patients with LBP.

Purpose: This study aimed to confirm the effects of visual feedback based eccentric pulley training (EPT) on muscle strength, pressure pain threshold, and chronic low back pain (CLBP). Methods: All subjects were randomly divided into 3 groups; 18 subjects in the visual feedback-based EPT (VF-EPT) group, 18 subjects in the EPT group and 18 subjects in the eccentric training (ET) group. All groups conducted 30 minutes of training per session, and the training was performed 3 times a week during 4 weeks. For muscle strength evaluation, all subjects were assessed for the muscle strength of trunk rotation, squat & trunk rotation, single-leg deadlift, seated lat pull down motion. For pain evaluation, Pressure Pain Threshold (PPT) was measured. Results: Results showed statistically significant changes in muscle strength in all groups (p<0.05), however, no significant difference was observed between groups. PPT was statistically significant in all groups (p<0.05) and differences were observed between groups (p<0.05). Conclusion: The results suggested that visual feedback training can be effective in improving muscle strength and pain control in patients with CLBP.

Objective To investigate the effects of early combined eccentric-concentric (ECC-CON) or concentric (CON) resistance training following total knee arthroplasty (TKA).Methods Patients who underwent a primary TKA were randomly assigned to an ECC-CON group (n=16) or a CON group (n=18). All patients received early, progressive resistance training with five sessions per week for 2 weeks starting 2 weeks after TKA. Isometric knee flexor and extensor strength of the surgical and non-surgical knees, instrumental gait analysis for spatiotemporal parameters, 6-Minute Walk Test (6MWT), Timed Up and Go Test (TUG), Timed Stair Climbing Test (SCT) were used to evaluate performance-based physical function. The Western Ontario McMaster Universities Osteoarthritis Index (WOMAC) and EuroQOL five dimensions (EQ-5D) questionnaire were used to evaluate self-reported physical function and self-reported quality of life. All patients underwent these evaluations before and 1 month after TKA.Results The ECC-CON group showed clinically meaningful improvements in extensor peak torque (PT) of the non-surgical knee, gait speed, and 6MWT from preoperative values. The CON group had an increase in H/Q ratio of the surgical knee and improvement in SCT-ascent postoperatively. Both groups showed significant improvements in WOMAC-Pain, function, and EQ-5D scores. Although extensor PT of the surgical knee did not reach the preoperative level in either group, the postoperative change was significantly less in the ECC-CON group than the CON group.Conclusion Early combined ECC-CON resistance training minimizes the loss in quadriceps strength of the surgical knee and improves endurance and gait speed after TKA.

목적 : 본 연구는 중심부 암점을 가진 환자에게 한글 기반의 중심외보기 훈련 소프트웨어를 적용하여 그 효 과성을 파악하고자 하였다. 연구방법 : ABA 단일대상연구(single-subject research design) 설계를 위해 중심부 암점을 가진 2명의 환자에게 훈련 전후 기초선 각 3회기, 중심외보기 훈련은 8회기를 시행하였다. 매회기 훈련 종료 후에 단 문읽기속도를 측정하였고, 훈련전과 훈련 후에 일기활동 능력을 평가하기 위하여 캐나다작업수행측정 (Canadian Occupational Performance Measure; COPM)와 운동처리기술평가(Assessment of Motor and Process Skills; AMPS)를 시행하였다. 결과 : 중심외보기 훈련 결과 대상자 모두의 읽기속도가 훈련 전보다 훈련 후에 2표준편차 이상 증가하였고, 특히 훈련 2-3회기에 큰 증가세를 나타냈다. 전반적인 일상생활활동 능력에서는 훈련 전후 변화가 없었 으나, 읽기와 관련된 활동에서는 의미있는 향상을 나타냈다. 결론 : 본 연구를 통하여 한글기반의 중심외보기 훈련 프로그램이 중심부 암점을 갖고 있는 환자의 읽기활동 수행 수준을 향상시킬 수 있음을 확인하였고, 국내 임상현장에서 적용할 근거를 마련하였다.

Objective : To examine the effects of the eccentric viewing training software on reading and Activities of Daily Living(ADL) for individuals with central scotomas in Korea. Methods : A single-subject A-B-A research design for two low-vision individuals with central scotomas was used to examine the effects. The research was conducted over 14 sessions, which included three sessions during a pre-training baseline period (A), eight sessions during an intervention period to apply eccentric viewing training software on Korean character stimulation (B), and three sessions in a post-training baseline period (A). To measure reading and ADL, participants were assessed for their reading speed, Canadian Occupational Performance Measure(COPM), and Assessment of Motor and Process Skills(AMPS). Results : An Analysis of the data showed that the participants’ reading speed increased compared to their pre-training baseline scores, showing the highest level of increase in the first two to three sessions of training. The participants improved their performance in the reading-related activities, although a comparison of their overall ADL function pre-training and post-training showed no change. Conclusion : These findings suggest that the eccentric viewing training based on specific language characters, Korean, is an effective intervention method for improvement in the reading skills of individuals with central scotomas.

본 연구는 중심부 암점 환자에게 적용하기 위한 한글기반 중심외보기 훈련 소프트웨어를 구성하고, 정안인을 대상으로 프로그램의 효과성을 파악하고자 하였다. 한글기반 중심외보기 훈련 소프트웨어는 신속순차시각제시를 이용한 한글자극으로 구성하였다. ABA 설계(ABA design) 개별실험연구설계를 위해 정안인 남자 대학생 2명에게 훈련 전후 기초선 각 3회기, 훈련은 3주간 8회기를 시행하고, 매회기 단문읽기속도를 측정하였다. 중심외보기 훈련 프로그램은 단어읽기 훈련 3단계와 문장읽기 훈련 2단계, 총 5단계로 구성하였다. 구성된 프로그램 훈련 결과, 단문읽기속도는 훈련전보다 훈련 후 2표준편차 이상 증가하였음을 나타냈다. 본 연구를 통하여 한글기반의 체계적인 중심외보기 훈련 소프트웨어를 구성하여 국내 임상현장에서 적용할 근거를 마련하였고, 사전연구를 통하여 중심외보기 훈련의 가능성을 확인할 수 있었다.

The aims of this study were to consist of the eccentric viewing training software based on Korean and to examine the effects on reading speed. The program was used the Korean stimuli by rapid serial visual presentation. Single-subject A-B-A’ research design for 2 normally-sighted young adults was used to examine the effect. The reading speed data on short-sentence of participants showed a statistically significant result, as both data from the intervention period and post-training baseline period deviated more than 2 standard deviations from the pre-training baseline period. Through this study, we suggested that eccentric viewing training software based on Korean characters stimulation would allow clinician in Korea to improve reading skills of low vision individuals with central scotomas.

The objective of this study was to determine the duration of maintained calf muscle flexibility gained in young adults with calf muscle tightness, as measured by increases in ankle active and passive dorsiflexion range of motion (DFROM) after three stretching interventions. Twenty subjects (5 men and 15 women) with calf muscle tightness received the following three stretching interventions in one leg (assigned at random): static stretching (SS), eccentric training on stable surface (ETS), and eccentric training on unstable surfaces (ETU). The subjects received all three interventions to the same leg, applied in a random order. Each intervention had a break of at least 24 h in-between, in order to minimize any carryover effect. Each intervention used two types of stretching: with the calf muscle stretched and both knees straight, and with the knee slightly bent in order to maximize the activation of the soleus muscle. All three interventions were performed for 200 seconds. We measured the duration of maintained calf muscle flexibility through active and passive ankle DFROM before intervention, immediately after intervention (time 0), and then 3, 6, 9, 15, and 30 min after intervention. We found a difference in the duration of maintained calf muscle flexibility between the three interventions. In the ETS and ETU interventions, a significant improvement in calf muscle flexibility, both ankle active and passive dorsiflexion ranges of motion (ADFROM and PDFROM), was maintained for 30 min. In the SS intervention, however, ADFROM before 9 min and PDFROM before 6 min were statistically different from the baseline. Our results suggest that ETS and ETU may be more effective than SS for maintaining calf muscle flexibility in young adults.

Purpose: The aim of this study was to determine the effects of isokinetic eccentric training (IET) on lower extremity muscle activation and walking velocity according to slow velocity and fast velocity of isokinetic eccentric training in stroke patients. Methods: Thirty subjects were randomly divided into three groups: experimental group I (n=10), group II (n=10), and control group III (n=10). Each group was provided intervention under three conditions, as follows: isokinetic eccentric training + slow velocity (group I), isokinetic eccentric training + fast velocity (group II), and sit to stand training (group III). The training program was conducted for eight weeks (five times per week; 30 minutes per day). Subjects were measured on lower extremity muscle (vastus lateralis, vastus medialis, gastrocnemius) activation and walking velocity. Analysis of covariance (ANCOVA) were performed for comparison of lower extremity muscle activation and walking velocity between different intervention methods. Results: Significant difference in lower extremity muscle activation and walking velocity was observed in experimental group I and group II compared with the control group III (p<0.01). Results of post-hoc analysis showed a significant in lower extremity muscle activation and walking velocity in group I compared with group II and group III. Conclusion: Findings of this study suggest that slow velocity and fast velocity using isokinetic eccentric training may have a beneficial effect on improvement of lower extremity muscle activation and walking velocity in stroke patients.

Purpose: The definition of eccentric viewing (EV) is using non-foveal preferred retinal loci (PRL) for viewing. The purpose of the present study was to investigate the clinical effect of EV training for low vision rehabilitation in patients with central scotomas. Methods: The direction of EV was monitored in 30 low vision patients with central scotomas by moving the patient’s view. The PRL was found by using a direct ophthalmoscope and retinal camera; the preserved visual field was identified using a kinetic visual field analyzer. The relationships between EV, PRL, and visual field were evaluated. The patients and their guardians were educated regarding EV. After 2 weeks of self-training, maintenance of EV was checked and changes in best-corrected visual acuity (BCVA), reading speed, and satisfaction questionnaire were evaluated. Results: A relationship between EV, PRL, and visual field was in accordance in half of the patients. There were no significant differences in demographics and basic visual characteristics in patients where the relationship was not in accordance. EV was maintained in two-thirds of the patients, but there were no significant differences in demographics and basic visual characteristics in patients who discontinued EV. There were no significant improvements in BCVA; however, reading speed and the satisfaction scores increased significantly with EV. Conclusions: The direction of EV was effectively detected by convenient access using an inexpensive method. Functional vision and satisfaction significantly improved following EV training. EV training can be used as an effective method for low vision rehabilitation in patients with central scotomas.

The purpose of this study is to identify the change in muscle strength and muscle tone of the lower back during four weeks of eccentric training using visual feedback to improve back muscle function. Thirty-six low back pain (LBP) patients recruited in this experiment. The subjects were randomly assigned 18 subjects each into a visual feedback based training group (VFG) and non-visual feedback based training group (NVFG). Both groups performed for 30 minutes using the same pulley device when performing the exercise once, and the training period was conducted 3 times a week for 4 weeks. For muscle function evaluation, muscle tone of both C7, L4 erector spine and hamstring were measured using myoton, and muscle strength of the same area was measured using dynamometer. Results showed statistically significant decreases only in muscle tone and elasticity at right C7 erector spine and stiffness at left L4 erector spine in VFG (p<0.05). Muscle strength improved overall in both VFG and NVFG (p<0.05).However, no significant difference between groups except the change in muscle strength of C7 erector spine. Therefore, selective application of VFG to improve in muscle function of LBP is required.

목적: 중심외주시 훈련 전후 대비감도를 검사하여 망막 주변부의 기능적 개선 여부를 알아보고자 하였다. 방법: 정상 시각을 가진 14명의 성인 남녀의 우안을 대상으로 중심와에서 $20^{\circ}$ 이측으로 떨어진 망막 주변부의 대비감도를 검사했다. 60분간 영상을 21일 동안 중심외주시 훈련 후 대비감도를 다시 검사하여 사후 검정했다. 결과: 시간적 가중에 따른 임계점 분석에서 중심외주시 훈련 전 0.7 cpd에서 임계점은 2.67(467 ms)이었으며 훈련 후 2.79(616 ms)로 증가했다 (p<0.05). 훈련 전 3.0 cpd에서 임계점 역시 2.53(341 ms)이었으며 훈련 후 3.04(1102 ms)로 증가했다(p<0.05). 결론: 중심외주시 훈련시 선명하고 작은 글씨체의 문자로 훈련하는 것을 권장하며 짧은 시간동안 자주 반복하는 것이 보다 효과적이다. 아울러, 저시력 환자에 대한 각 병변별 시재활훈련을 할 수 있는 기준에 대한 연구가 절실하다.

Purpose: This study was to investigate the functional improvement in peripheral vision following eccentric viewing training. Methods: 14 subjects with normal vision took a part with their right eye, peripheral retinal which is $20^{\circ}$ lateral area from the fovea was examined for contrast sensitivity(CS). Eccentric viewing training was performed for 21days with an hour image viewing and examination was repeated. Results: The critical durations for 0.7 cpd were increased 2.67(467 ms) for pre-eccentric viewing training to 2.79(616 ms) for post-eccentric viewing training (p>0.05). The critical durations for 3.0 cpd were also increased 2.53(341 ms) for pre-eccentric viewing training to 3.04(1102 ms) for post-eccentric viewing training (p>0.05). Conclusions: It is recommended to use higher spatial frequency with higher CS for eccentric viewing training and to train more frequently for a short time. Moreover, the study on Korean standardizing of the visual rehabilitation for low vision based on the etiology is sorely required.

목적: 황반변성을 가진 저시력 환자의 중심외주시 훈련에 사용되는 망막 주변부의 특성을 조사하여 재활치료용 주변시 연구에 도움이 되고자 한다. 방법: 정상 시각을 가진 30명의 성인 남녀의 우안을 대상으로 중심와에서 $20^{\circ}$ 이측으로 떨어진 망막 주변부의 생리적 가중을 측정하였다. 표적은 원형의 수직형 정현파였으며 공간주파수 0.7 cpd와 3.0 cpd를 사용하여 공간적 가중과 시간적 가중의 임계값을 비교하였다. 결과: 0.7 cpd에서 시간적 가중의 임계점은 540 ms, 대비감도는 1.1이었으며 3.0 cpd에서는 315 ms, 대비감도는 0.98이었다. 0.7 cpd에서 공간적 가중의 임계점은 $11.3^{\circ}$, 대비감도는 2.8이었으며, 3.0 cpd에서 임계점은 $5^{\circ}$, 대비감도는 2.63이었다. 결론: 주변시는 중심시보다 더 빨리 임계점에 도달한다. 중심외훈련시에는 저주파대역을 대상으로 긴 시간동안 훈련하기 보다 짧은 시간동안 자주 훈련하기를 권장한다.

Purpose: This study was to investigate peripheral vision and provide people with macular degeneration with a guideline for eccentric viewing training. Methods: 30 adult subjects with normal vision took part in this study. The lateral area of $20^{\circ}$ eccentricity from the fovea of right eye was only used to measure the physiological summation. The target was sinusoidal vertical gratings within a circular aperture. The critical points in spatial and temporal summation was found to compare each other for 0.7 cpd and 3.0 cpd, respectively. Results: Critical duration and contrast sensitivity for 0.7 cpd were 540 ms and 1.1, and 315 ms and 0.98 for 3.0 cpd respectively. The critical degrees and contrast sensitivity for 0.7 cpd were $11.3^{\circ}$ and 2.8, and $5^{\circ}$ and 2.63 for 3.0 cpd respectively. Conclusions: The critical point in peripheral vision reaches relatively faster than the one in central vision. It is recommended to train the peripheral retina under the lower spatial frequency more frequently for a short time than constantly for a long time.

목적: 단기간의 중심외주시 훈련 후 발생하는 신경의 재조직화의 특성과 호발 위치를 알아보고자 했다. 방법: 정상시력을 가진 성인 14명을 대상으로 21일 간 중심외주시 훈련을 하고 훈련 전후 광지각도와 다국소망막전위도를 측정하여 사후 분석했다. 결과: 중심외주시 훈련 전후 값을 비교한 광지각도 검사(p<0.047)에서 뿐만 아니라 다국소망막전위도 검사에서도 유의한 개선을 보였다(p<0.028). 결론: 시각 말초신경계는 재생이 불가능하지만 단기간의 중심외주시 훈련은 말초신경계에서 신경 재조직화를 발생시킨다.

Purpose: This study was to investigate the properties and the location of neural reorganization following eccentric viewing training. Methods: 14 subjects with normal vision took part in eccentric viewing training. The measurements of the light sensitivity and multifocal electroretinogram were performed before and after the training. Results: The measurements of the light sensitivity and multifocal electroretinogram for pre-eccentric viewing training and post-eccentric viewing training showed the significant difference (p<0.047 and p<0.028, respectively). Conclusions: The retinal outer plexiform layer is unable to regenerate. However, the neural reorganization in the retinal outer plexiform layer is able to take place following eccentric viewing training.