Background: Landing from a step or stairs is a basic motor skill but high incidence of lateral ankle sprain has been reported during landing with inverted foot. Objects: This study aimed to investigate the effect of landing height and visual feedback on the kinematics of landing and supporting lower limbs before and after the touch down and the ground reaction force(GRF)s. Methods: Eighteen healthy females were voluntarily participated in landing from the lower (20 cm) and the higher (40 cm) steps with and without visual feedback. To minimize the time to plan the movement, the landing side was randomly announced as a starting signal. Effects of the step height, the visual feedback, or the interaction on the landing duration, the kinematic variables and the GRFs at each landing event point were analyzed. Results: With eyes blindfolded, the knee flexion and ankle dorsiflexion on landing side significantly decreased before and after the touch down. However, there was no significant effect of landing height on the anticipatory kinematics on the landing side. After the touch down, the landings from the higher step increased the knee flexion and ankle dorsiflexion on both landing and supporting sides. From the higher steps, the vertical GRF, anterior GRF, and lateral GRF increased. No interaction between step height and visual feedback was significant. Conclusion: Step height and visual feedback affected the landing limb kinematics independently. Visual feedback affected on the landing side while step height altered the supporting side prior to the touch down. After the touch down, the step height had greater influence on the lower limb kinematics and the GRFs than the visual feedback. Findings of this study can contribute to understanding of the injury mechanisms and preventing the lateral ankle sprain.

목적 : 본 연구는 시청각 피드백 기반 시지각 디지털 페그보드 훈련이 좌측 편마비 환자의 시각-운동 통 합 및 인지기능에 미치는 효과에 대해 알아보고자 하였다. 연구방법 : 본 연구는 좌측 편마비 환자 26명을 대상으로 시청각 피드백 기반 시지각 디지털 페그보드 훈련을 적용한 실험군 13명과 도형에 따라 페그를 꽂는 시지각 과제를 적용한 대조군 13명을 무작위로 나누어 주 3회, 30분씩, 12주간 총 36회에 따라 훈련을 적용하였다. 시각-운동 통합 평가는 Beery 시각- 운동 통합 검사 6판(Beery-Buktenica Developmental Test of Visual-Motor Integration-Sixth; Beery VMI-6), 인지기능 평가는 신경행동학적 인지상태 검사(Neurobehavioral Cognitive Status Examination; NCSE)를 사용하였으며, 각 훈련 전후에 따른 효과의 변화를 확인하였다. 결과 : 첫째, 시각-운동 통합의 변화에서는 실험군과 대조군 사이에 시각-운동 통합, 시지각, 운동 협응에서 통계학적으로 유의한 차이가 나타났다(p < .05). 둘째, 인지기능의 변화에서는 실험군과 대조군 사이에 주의집중력, 구성능력, 기억력, NCSE 전체점수에서 통계학적으로 유의한 차이가 나타났다(p < .05). 결론 : 본 연구에서는 시청각 피드백 기반 시지각 디지털 페그보드 훈련이 좌측 편마비 환자의 시각-운동 통합 및 전반적인 인지기능에 긍정적인 효과가 있음을 알 수 있었고, 이를 토대로 작업치료 임상 환경에서 뇌졸중 환자에게 해당 훈련을 적용한다면 시각-운동 통합 및 인지기능 개선에 긍정적인 효과가 있을 것이다.

Background: Flexible flat foot is that the medial longitudinal arch collapses in weight bearing and returns normal arch when weight is removed and the weight bearing shifts toward medial part of the foot, which can cause pathological problems in the alignment of the lower extremities and the entire body. Objective: To compare the foot pressure for adults with flexible flat foot. Design: Quasi-Experimental Study Methods: 24 participants with flexible flat foot were recruited and were randomly divided into Visual feedback Short Foot Exercise (VSFE) group and Short Foot Exercise (SFE) group. To compare changes of foot pressure about pre and post intervention, the contact pressure measurement was conducted. Results: In the VSFE, significant differences were observed for the foot pressure of the 1st toe, 1st, 3rd and 4-5th metatarsal, midfoot, medial and lateral heel (p<.05). The foot pressure of the 3rd and 4-5th metatarsal, midfoot showed significant differences in the SFE (p<.05). The contact pressure of the 1st toe, 3rd metatarsal showed significant differences between the groups. Conclusions: Visual feedback short foot exercise can be useful for moving the pressure from medial to lateral part, and can prevent possible pathological problems.

Background: Stroke patients show abnormal walking patterns due to brain injury. In order to have the desired walking pattern, appropriate stimulation is required to activate the central pattern generator. For this reason, our study performed treadmill ambulatory training with rhythmic auditory stimulation. However we did not consider the influence of visual feedback. Objects: The purpose of this study was to compare the gait abilities in chronic stroke patients following either treadmill walking training with rhythmic auditory stimulation and visual feedback (TRASVF) or treadmill walking training with rhythmic auditory stimulation (TRAS) alone. Methods: Twenty-one stroke patients were divided into two groups: A TRASVF group (10 subjects) and a TRAS group (11 subjects). They received 30 minutes of neuro-developmental therapy (NDT) and walking training for 30 minutes, five times a week for three weeks. Temporal and spatial gait parameters were measured before and after the training period. The Biodex gait trainer treadmill system measured gait parameters. Results: After the training periods, the TRASVF group showed a significant improvement in walking speed, the step length of the affected limb, and time on each foot of the affected limb when compared to the TRAS group (p<.05). Conclusion: The results of this study showed that the treadmill walking training with rhythmic auditory stimulation and visual feedback improved individual gait ability more than the treadmill walking training with rhythmic auditory stimulation alone. Therefore, visual feedback should be considered along with rhythmic auditory stimulation training.

Background: The toe-spread-out (TSO) exercise has been introduced as a strengthening exercise for the abductor hallucis muscle in subjects with hallux valgus. Visual biofeedback using ultrasound imaging during exercise, may increase the ability to selectively contract the abductor hallucis muscle, compared with exercise alone. Objects: The aim of this study was to investigate the effects of ultrasound imaging visual feedback during the TSO exercise with respect to its influence on the angle of the first metatarsophalangeal joint (1st MPJ) and the cross-sectional area (CSA) of the abductor hallucis muscle in subjects with hallux valgus. Methods: Twenty-five healthy young subjects with a mean average age of 22.5 years, and a standard deviation of 2.3 years, were recruited for this study. Hallux valgus was defined as an angles greater than 15° angle of 1st MPJ. Goniometric measurement was used to determine the angle of 1st MPJ. In addition, an ultrasound system was used to collect the CSA of the abductor hallucis muscle in each foot. The angle of the 1st MPJ and CSA of the abductor hallucis were measured in three positions; the resting position, during TSO exercise, and during TSO exercise in conjunction with real-time ultrasound imaging feedback. All data analyzed using a repeated analysis of variance with Bonferroni correction in order to compare the dependent variables in all three positions. Statistical level of significance was set up as p<.05. Results: The angle of the 1st MPJ was noted to be significantly reduced and the CSA of the abductor hallucis to be significantly greater during TSO exercise used in conjunction with ultrasound imaging visual feedback, compared to when the values were recorded during TSO exercise alone (p<.05). Conclusion: Based on these findings, it can be concluded that the application of ultrasound imaging visual feedback during TSO exercise is more effective in contracting selectively the abductor hallucis than the use of exercise alone.

The aim of this research was to investigate how the effects of body supported treadmill training with visual feedback affect the gait factors of stroke patients. Thirty subjects (21 male, 9 female) with a diagnosis of stroke were taken to the hospital to participate in this study. The subjects received body supported treadmill training with visual feedback. The training was executed for 6 minutes, 3 times a day per week for 19 weeks after general exercise. The effects of the visual feedback in the body supported treadmill training were evaluated by measuring the average gait cycle and the average step length of the affected and unaffected. The collected data were statistically analyzed by using a paired t-test. The results of this study were a significant improvement of the average gait cycle and no statistically significant difference of the average step length. The gait cycle average had a statistically significant difference in gender, age, etiology, paretic side, and step length average. There was no statistically significant difference in infarction within etiology. Therefore, it was necessary to apply the easy and simple with the treadmill training in the rehabilitation of the stroke patients. This study will require a variety of outcome measures related to the effects of treadmill training with gait factors.

The purpose of this study was to investigate the effect of visual feedback on the postural control of stroke patients, by systematically varying conditions of visual feedback [eye-open condition (EO) vs. eye-closed condition (EC)], and base-support (both-side support, affected-side support, and unaffected-side support). In this study, we allocated 41 stroke patients with no damage in the cerebellum and visual cortex who can walk at least 10 meters independently, and 35 normal adults who have no experience of stroke to the control group. Both groups were asked to perform a "sit-to-stand" task three to five times, and their postural control ability was measured and compared in terms of asymmetric dependence (AD) instead of the traditional symmetric index (SI) in the literature. The results showed that although both subject groups maintained better postural control in the EO condition than in the EC condition, the patient group appeared to be more stable in EC than in EO when they were required to perform the task of the support condition given on the affected side. These results implied that visual feedback can impair stroke patients' postural control when it is combined with a specific support condition.

목적 : 본 연구의 목적은 시각되먹임 제공 및 차단으로 시행된 자세수직훈련의 효과를 비교함으로써, 시각되먹임을 차단한 자세수직훈련이 뇌졸중 밀기증후군 환자의 기능회복 및 일상생활동작에 어떠한 영향을 미치는지 알아보고 자 하였다. 연구방법 : 본 연구는 개별사례 교차중재 연구설계 중 대상자간 다중기초선을 이용하였으며, 밀기증후군 환자 3명 을 대상으로 하였다. 기초선 측정은 대상자 1이 4회, 대상자 2가 7회 그리고 대상자 3이 10회였으며, 치료회기는 대상자 1이 14회, 대상자 2가 11회 그리고 대상자 3이 8회였다. 치료중재는 대상자 1이 14회, 대상자 2가 11회 그 리고 대상자 3이 8회였다. 밀기증상의 기능회복 평가는 밀기 증후 척도, 일상생활동작을 평가하기 위하여 바델지 수 및 실험 전∙후 대칭적인 서기자세를 평가하기 위하여 근전도기로 양측 중둔근에서 근활성도를 측정하였다. 결과 : 시각되먹임을 차단한 자세수직훈련이 적용되었을 때 대상자 1, 2, 3의 밀기 증후 척도는 각각 기초선과 비교 하여 52.4%(5.3점에서 2.8점), 36.4%(4.4점에서 1.6점) 및 23.6%(3.6점에서 0.9점) 향상되었다. 시각되먹임을 제공한 자세수직훈련은 42.9%(5.3점에서 2.3점), 26.1%(4.4점에서 1.2점) 및 13.2%(3.6점에서 0.5점) 향상되었다. 대상자 1, 2, 3의 바델지수는 각각 기초선과 비교하여 22.4%(44.3점에서 54.1점), 15.5%(44.7점에서 51.6 점) 및 15.8%(51.5점에서 59.6점) 향상되었다. 시각되먹임을 제공한 자세수직훈련은 17.0%(44.3점에서 51.8점), 11.4%(44.7점에서 49.8점) 및 14.8%(51.5점에서 59.1점) 향상되었다. 또한 실험 전과 비교하여 실험 후 환측의 중둔근 근활성도가 더 크게 향상되었다. 결론 : 교대로 적용된 치료중재 결과를 통하여 시각되먹임을 차단한 자세수직훈련이 시각되먹임을 제공한 자세수직훈련보다 밀기증후군 환자의 기능회복 및 일상생활동작능력에 더 효과적인 것으로 나타났다. 향후에는 많은 대상자를 포함시키고 오랜 기간 동안 적용한 연구들이 계속 이어져야 할 것이다.

The purpose of this study was to examine whether there were any changes in motor skills, motor knowledge, and participation level in two different groups that were given feedback based on the results of descriptive visual evaluation and through the verbal

목적 : 척수손상 환자를 대상으로 시각피이드백을 이용한 휠체어 추진이 척수손상 환자의 균형 특성에 미치는 영향을 알아보고자 하였다. 연구방법 : 척수 완전 손상 환자 38명을 대상으로 휠체어 추진 시뮬레이션 장치와 휠체어를 추진하지 않는 경우와 추진하는 경우 시각피이드백 이용유무에 따른 둔부와 대퇴부의 압력분포와 압력중심이동 변화를 측정하기 위해 좌석시트 압력분포 측정도구인 FSA를 사용하였다. 이들 실험도구들을 이용하여 얻은 결과는 다음과 같다. 결과 : 1) 시각피이드백 이용 없이 휠체어를 추진하지 않는 경우와 추진하는 경우에 압력중심의 흔들림이 유의한 차이가 있었다(p<.05). 2) 휠체어 추진 시 시각피이드백을 이용하지 않은 경우보다 시각피이드백을 이용한 경우에 척수손상 레벨에 상관없이 압력중심의 흔들림이 모두 감소되었다. 시각피이드백 이용 유무에 따라 흉수상부 손상, 흉수하부 손상, 요수 손상 환자에 있어서는 유의한 차이를 보였다(p<.05). 3) 경수 손상 환자의 부위별 좌석시트 압력분포 평균을 보았을 때, 휠체어 추진 시 둔부전방 > 둔부후방 > 대퇴부 후방 > 대퇴부 전방 순으로 압력이 분포되었으며, 휠체어를 추진하면서 시각피이드백을 이용한 경우의 부위별 압력 증가비율을 계산한 결과, 둔부전방과 대퇴부 부위로 더 많은 압력증가가 생겼다. 4) 흉수상부 손상 환자의 부위별 좌석시트 압력분포 평균을 보았을 때 휠체어 추진 시 둔부전방 > 대퇴부 후방 > 둔부후방 > 대퇴부 전방 순으로 압력이 분포되었으며, 휠체어를 추진하면서 시각피이드백을 이용한 경우의 부위별 압력 증가비율을 계산한 결과 둔부전방과 대퇴부 부위로 더 많은 압력증가가 생겼다. 5) 흉수하부 손상 환자의 부위별 좌석시트 압력분포 평균을 보았을 때 휠체어 추진 시 둔부전방 > 대퇴부 후방 > 둔부후방 > 대퇴부 전방 순으로 압력이 분포되었으며, 휠체어를 추진하면서 시각피이드백을 이용한 경우의 부위별 압력 증가비율을 계산한 결과 대퇴부 부위로 더 많은 압력증가가 생겼다. 6) 요수 손상 환자의 부위별 좌석시트 압력분포 평균을 보았을 때 휠체어 추진 시 둔부전방 > 둔부 후방 > 대퇴부 후방 > 대퇴부 전방 순으로 압력이 분포되었으며, 휠체어를 추진하면서 시각피이드백을 이용한 경우의 부위별 압력 증가비율을 계산한 결과 둔부후방으로의 압력 증가비율이 가장 많이 증가하고, 다음으로 대퇴부 전방, 그리고 대퇴부 후방 순이었다. 결론 : 시각피이드백을 이용한 휠체어 추진 시 척수손상 레벨에 상관없이 압력중심의 흔들림이 모두 감소하였다. 또한, 전방 또는 전후방으로의 압력분포 변화를 통해 균형의 향상을 가져올 수 있는 움직임이 더 증가하는 경향이 있었다. 이를 통해 시각피이드백을 이용한 휠체어 추진이 척수손상 환자의 균형능력 향상에 도움을 줄 수 있음을 보여주었다.

Theoretical framework of motor learning is used to enhance perceptual motor skill in physical therapy intervention, which can be subdivided into two main types-explicit and implicit. The purpose of this study was to examine whether stroke patients with unilateral brain damage learn implicitly a motor skill using the arm ipsilateral to the damaged hemisphere. Speculation then followed as to the formation of therapeutic plans and instructions provided to patients with stroke. 20 patients with stroke and 20 normal participants were recruited. All the subjects practiced serial reaction time tasks for 30 minutes a day and retention tests on the following day. The tasks and tests involved pressing the corresponding buttons to 4 colored circles presented on a computer screen as quickly and accurately as possible. Patients with stroke responded more slowly than controls. However, both groups showed decreased reaction time in the experimental and retention periods. Also, there was no significant difference between both groups regarding explicit knowledge of consecutive order. Therefore, patients with stoke had the ability to learn implicitly a perceptual motor skill. Prescriptive instruction using implicit and explicit feedback may be beneficial for motor skill learning in physical therapy intervention for patients with brain damage.

Physical therapists have been using biofeedback training to induce improvements in various circumstances. The purpose of this study was to compare the effects of visual and tactile feedback using electrical stimulation on quadriceps strength. Nineteen women without known impairment of the neuromusculoskeletal system volunteered for this study. Subjects were randomly allocated into three groups: visual feedback, tactile feedback, and control group. The torque of isometric knee extension force was measured. Subjects were asked to exert the maximal isometric contraction force of quadriceps over a 30 second period. The resting period of 10 minutes was given after the maximal isometric contraction to avoid the muscle fatigue. In between groups comparison, significant differences of the peak torque and the torque area were found on the performance of the maximal isometric contraction of quadriceps (p<.05). The values peak of torque and torque area were significantly higher during visual feedback than tactile feedback. The results of this study suggest that visual feedback is more powerful than tactile feedback (p<.01).

The purpose of this study was to find a more effective balance training method. The subjects of this study were 14 children with cerebral palsy (7 males, 7 females) being treated at Seran Pediatric Developmental Research Center in Taegu. Two groups of children with cerebral palsy (everyday trained group, every-other-day trained group) were evaluated with visual & auditory feedback. Evaluation and training device was Balance Performance Monitor (BPM) Dataprint Software Version 5.3. There was statistically significant difference of the balance score between the pre-and the post-training in both group (p<.05), but there was no difference of the balance score between two groups (p<.05). In conclusion, it is likely that the visual and auditory feedback in children with cerebral palsy was effective in improving standing balance, but there was no difference between everyday trained group and every-other-day trained group.

Patients with hemiplegia usually show different body weight distribution as compared with normal subjects. Asymmetrical posture during static stance has been identified as a common problem in patients with hemiplegia. The purpose of this study was to identify the effects of vision and visual feedback on body weight distribution while standing under three conditions: eyes-closed, eyes-open and visual feedback condition. Fourteen patients with hemiplegia participated in the study. Their body weight distribution during standing for 20 seconds was measured by Limloader. The data were analysed by repeated measure of one-way ANOVA. The weight bearing on the paretic limb in the eyes-open condition was significantly higher than that of the eyes-closed condition. The weight bearing on the parietic limb in the visual feedback condition was significantly higher than that of the eyes-open condition. These results suggest that patients with hemiplegia can improve their symmetrical stance ability using visual feedback.

To improve the effect of balance training, visual feedback is usually used. During the training process there are some factors which decrease the effect. Neurophysiologically, the main negative factor is thought to be synaptic fatigue which decreases the sensitivity of synapses. The purpose of this study was to find a more effective balance training method. In this study, a total of 60 normal subjects-19~30 years old young males and females(M=30, F=30)-participated, and they were randomized as A, B, and C group, each group containing 20 subjects. First, all groups had a pre-test of sway balance. One minute later, A group was trained in sway balance by continuous visual feedback for 2 minutes, B group by intermittent visual feedback which had 4 sessions of 30 seconds each and a one minute rest break. C group was not trained at all. All groups had a post-test. Only B group had improved balance compared with C group by ANOVA. On the other hand, intermittent visual feedback was more effective than continuous visual feedback in sway balance training with normal subjects.ㅂ

The objective of this study was to identify the effects of weight-transfer training on the weight bearing distribution and gait patterns of hemiplegic patients through visual and auditory feedback using a limb load monitor. The subjects of this study were 18 hemiplegic patients who had been hospitalized or were visited out-patient department of the Rehabilitation Hospital, College of Medicine, Yonsei University, from January 5, 1995 through March 15, 1995. Pre-and post-training changes in gait patterns were measured using ink foot prints as well as by recording weight bearing distribution using a limb load monitor. The data were analyzed by the repeated measure one-way ANOVA and paired t-test. The finding were as follows: 1. Prior to the training, 18 subjects bore more weight on the sound leg(61.6 %) than on the affected leg(38.4 %). 2. Posterior to the training, the average percentage of weight bearing on the affected leg increased significantly from 38.4 % prior to training; to 46.0 % immediately after training; 45.7 % after a 30 second delay; and 45.3 % after a 60 second 3. The difference in gait patterns between pre- and post- training was statistically significant, with an increase in gait velocity to 3.65 cm/sec post-training; an increase in stride length to 5.37 cm on the affected side; 4.77 cm on the sound side; and a narrowing of the base of support to 1.19 cm. In conclusion, hemiplegic weight-transfer training using visual and auditory feedback with a limb load monitor was found to be enhancing symmetrical standing posture, and simultaneously improve gait patterns.

Biofeedback devices have been used successfully to improve head control and symmetrical walking in cerebral palsied children. Biofeedback of postural sway was investigated as a therapeutic technique to reduce postural abnormality in 24 selected children with cerebral palsy. Subjects were evaluated their weight distribution of both sides during their standing before and after the visual and auditory feedback training. The effectiveness of biofeedback was compared to conventional physical therapy practices in reestabilishing symmetrical standing in cerebral palsied children. Our study found biofeedback was effective in training symmetrical standing posture.

최근 BCI(Brain Computer Interface) 기술의 발전과 함께 보급형 BCI 장치를 활용한 게임 연구가 활발히 진행되고 있다. BCI 게임은 대부분 연구를 위한 실험적인 체험용 콘텐츠 형태로 개발되어 왔으며, 명령 패러다임에 있어서 BCI 게임 명령에 적합한 뇌파를 유도하는 방법에 대한 연구는 미흡하다. 본 연구에서는 음악의 리듬을 시청각적으로 표현하는 새로운 플레이 요소를 제공하는 BCI 리듬게임과 음악의 템포와 뇌파를 동기화 시켜 다양한 형태의 시청각 피드백을 생성하는 방법을 제안한다. 제안방법은 실험을 통해 게임조작에 필요로 하는 뇌파를 유도하여 게임점수를 향상시킬 수 있음을 확인하였다.

본 연구는 시각 피드백이 조준 운동의 제어에 미치는 영향을 알아보기 위하여 시각 피드백 처리시간을 과대 평가할 가능성이 있는 요인들을 통제한 상황에서 시각 피드백과 시각 피드백 관련 변인들을 체계적으로 다양하게 통제하여 유사한 네 개의 실험을 수행하였다. 실험1은 다양한 속도로 수행되는 운동하에서 시각 피드백을 다양한 시점에서 철회하여 시각 피드백이 동작실행의 정확성에 미치는 영향을 관찰함으로써 시각 피드백 처리시간을 알아 보려는 의도로 수행하였다. 이와 동시에 시각정보가 일정시간(최소한 250㎳)동안 감각기억(sensory memeoy)의 형태로 표상화되어 기억됨으로써 감각기억에 기초를 둔 동작 제어의 가능성을 검증하기 위함이었다. 실험은 3×5의 2요인 피험자내 설계를 이용하여 시각 피드백과 동작시간 요인을 통제한 가운데 단일 표적조준과제를 이용하여수행하였다. 실험2는 빠른 속도(160㎳)로 수행되는 운동하에서 시각의 철회를, 동작개시를 시점으로 다양하게 지연시켜 시각조건과 비교함으로서 동작 수행 중 시각정보가 어떠한 시점에 영향을 미치는지를 알아보려는 목적으로 수행하였다. 실험은 단일요인 피험자내 설계를 이용하였으며, 실험조건은 시각 피드백을 통제하는 다섯 가지 조건으로 구성하였다. 실험3은 예비신호와 동시에 철회하였던 시각 피드백을 반응신호, 동작개시와 동시에 그리고 동작개시 60㎳후에 부여하여 시각이 조준 동작을 사전에 정하는 데 사용되는 것을 방지한 상황에서 동작실행의 정확성을 관찰함으로써 시각 피드백이 동작실행의 정확성에 미치는 영향을 관찰하고자 하였다. 실험은 단일 요인 피험자내 설계를 이용하였으며, 실험조건은 시각 피드백을 통제하는 네 가지 조건으로 구성하였다. 실험4는 동작거리와 동작시간 그리고 시각 피드백을 통제하는 가운데 동작실행의 정확성을 관찰하여 시각 피드백이 조준운동의 제어에 미치는 영향을 규명하고자 하였다. 실험은 2×2×3의 3요인 피험자내 설계가 이용하여 동작거리와 동작시간 그리고 시각 피드백이 통제되는 가운데 실험을 수행하였다. 수집한 자료를 일차적으로 반응시간과 동작시간에 의하여 자료로서의 채택 여부를 검토한 뒤에 동작실행의 정확성(동작오차)을 분석한 결과, 다음과 같은 결론을 얻었다. 첫째, 시각 피드백은 200㎳ 이내에 빠른 시간에 처리될 수 있다. 둘째, 거리오차의 경우 시각 피드백은 동작의 후기 단계에서 중요하며, 방향오차의 경우에는 시각 피드백이 동작의 초기 단계에서 중요하다. 셋째, 시각조건과 비시각조건 간에서 동작오차의 차이는 150-300㎳의 동작시간에서는 일정하였으나 450㎳의 동작시간에서는 증가하였다. 그리고 이러한 경향은 동작거리가 길수록 강하게 나타났다.