The Effects of Visual Field Conditions on Electromyography of the Lower Extremities during Reaching Tasks in Healthy Adults

The effect of visual field condition on kinetic in upper extremities and e.m.g in lower extremities while performing reaching in normal adults

[Purpose] The aims of this study was to investigate mean velocity and angle of shoulder joint, activation of tibialis anterior and gastrocnemius according to both eyes, dominant eye and non-dominant eye condition during reaching task in normal adults. [Subjects and Methods] Our research recruited 24 participants (male 11, female 13) in Silla University. Participants were performed reaching out movement by conditions of both eye, dominants eye, non-dominants eye. The target was placed at 45 degree diagonal direction and distance far away 130% of their arm length. Kinetic analysis of the upper extremities was investigated by QUALISYS 3-dimensional motion analysis system. Muscle activation were measured by EMG during reaching tasks. The collected data were statistically processed using the SPSS for win version 20.0. [Results] There was a significant difference of shoulder joint velocity of flexion, abduction and internal rotation according to visual field condition during reaching tasks. There was no significant difference of shoulder joint angle and muscle activation according to visual field conditions during reaching tasks. [Conclusion] In conclusion, visual field has an influence on shoulder joint velocity. Therefore, the visual field may be to play an important role in reach performance.

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.