Biomechanical Effect of Foot Orthoses on Rearfoot Motions and Joint Moment Parameters in Patients with Flexible Flatfoot.

BACKGROUND The effect of foot orthoses in terms of kinematics and kinetics during walking could be affected on different geometrical designs. Therefore, the purpose of this study was to compare the biomechanical and clinical effects of 3 different insoles on rearfoot motion (RFM) and ankle joint moment parameters. MATERIAL AND METHODS Twenty eight university students with flexible flatfoot were recruited for this study, and each participant was asked to wear 3 different insoles: normal insole without arch support function, type A insole with only arch support function, and type B insole with both arch support and cushion pads for shock absorbing functions. Three-dimensional motion analysis was performed to compute the ranges and peak orientation angles of RFM and ankle joint moment parameters. RESULTS The type A and type B insoles exhibited significantly smaller peak everted position and evertor moment than the normal insole. Also, the type A insole showed significantly smaller range of rearfoot motion in the longitudinal axis and the length of MA (moment arm) in the mediolateral axis than the normal insole. CONCLUSIONS The use of the type A insole using arch support function was induced to promote a cautious gait pattern associated with a relatively lower potential risk compared to the normal insole. The type A and type B insoles could be important to positively reduce the possibility of injury. Also, the smaller length of MA in the type A insole might have a contribution to the decrease of ankle joint evertor moment.

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.

The effects of stretching exercise for upper trapezius on the asymmetric rate of bite force.

[Purpose] The purpose of this study was to observe the effects of stretching the upper trapezius muscle on the asymmetric rate of bite force. [Subjects] Forty-seven female university students who had all their original teeth, had no disorders in the temporomandibular joints, and had never worn braces; participated in this study. [Methods] An occlusometer was used to measure biting forces. Subsequently, stretching exercises of the upper trapezius were performed. The subjects were divided into 3 groups at the start of the testing: the asymmetric rate of the first group was less than 10%; the asymmetric rate of the second group was between 10% and 20%; and the asymmetric rate of the third group was more than 20%. The stretching exercises were done on the dominant side of the upper trapezius. [Results] After the stretching exercises of the upper trapezius, the results showed that for the first group, whose asymmetric rate of biting force was less than 10%, there was a significant increase in asymmetric rate (from 5.1% to 10.3%). For the second group, whose asymmetric rate of biting force was measured to be between 10% and 20%, the asymmetric rate decreased from 14.7% to 14.3%, but the change was not statistically significant. For the third group, whose asymmetric rate of biting force was more than 20%, there was a significant decrease in asymmetric rate (from 27.8% to 12.6%). [Conclusion] We concluded that stretching exercises of the upper trapezius muscle had a direct effect on the asymmetric rate of biting force.

Effects of combined exercise on changes of lower extremity muscle activation during walking in older women.

[Purpose] The purpose of this study was to demonstrate the effects of combined exercise for a period of 12 weeks on the changes in lower extremity muscle activation during walking in older women. [Subjects] The subjects of this study were 22 elderly women who were 65 years of age or older and living in B-City. The subjects had no nervous system or muscular system diseases that might affect walking in the previous two years. [Methods] Muscle activation was measured by using surface EMG (QEMG-8, Laxtha, Daejeon, Republic of Korea). The subjects were asked to walk on an 8 m of footpath at a natural speed. In order to minimize the noise from the cable connecting the EMG measuring instrument to the electrodes, tape was used to affix the electrodes so that they would not fall off the subjects. The EMG data were analyzed by using the RMS. [Results] Muscle activation of the rectus femoris, biceps femoris, tibialis anterior, and gastrocnemius was increased significantly after combined exercise for 12 weeks. However, no increase was observed in the left biceps femoris. [Conclusion] It was demonstrated that our exercise program, which includes aerobic walking exercises, senior-robics, and muscle strengthening exercises using elastic bands, is very effective for reorganizing the normal gait pattern in the cerebral cortex and improving muscle strength.

The effects of elbow joint angle changes on elbow flexor and extensor muscle strength and activation.

[Purpose] This research investigated the relationship between elbow joint angle and elbow flexor and extensor strength and activation, taking into consideration the length-tension tension curve of the muscle. [Subjects] There were 30 research subjects in total, 15 male and 15 female college students from Busan S University who had no functional disabilities that might affect measurement of muscle strength and muscle activation, and none had they experienced any damage in their upper extremities or hands. [Methods] The elbow joint angles were positioned at angles of 56°, 70° and 84°, and then muscle strength and activation were compared. Repeated measures ANOVA was used for statistical analysis, and the paired t-test was used to identify the difference between each angle. We used the SPSS for windows (ver. 21.0) statistical software and a significance level of α=0.05. [Results] The results showed that muscle strength and activation of the biceps was highest when the joint was placed at 56°. On the other hand, for the triceps, the result was highest when the joint angle was placed at 84°. [Conclusion] The tests confirmed that muscle strength and activation were highest at the joint angle at which the muscle was stretched to 20% more than the resting position in concentric contraction.

The effects of active scapular protraction on the muscle activation and function of the upper extremity.

[Purpose] The purpose of this study was to determine the effects of adjusting the scapula into its ideal position through active scapular protraction on the muscle activation and function of the upper extremity. [Subjects] Twenty female college students aged 19-21 without any physical or functional disability were the subjects of this study. They had no history of injury to their upper extremities or hands. [Methods] After the initial measurements the experimental group was asked to perform active scapular protraction; then, their grip strength and muscle activation were measured again. Every action was maintained for 5 seconds and repeated 3 times. The mean values of the measurements were analyzed. A resting of 1 minute was given between each action. [Results] The results revealed a significant change in the experimental group's grip strength after active scapular protraction had been performed. The surrounding muscles of the scapula, such as the serratus anterior, upper trapezius, flexor carpi ulnaris, flexor carpi radialis and palmaris longus, showed significant changes in muscle activation after active scapular protraction. The muscles of the upper extremity also showed significant changes after active scapular protraction. [Conclusion] The adjustment of scapula into its ideal position through active scapular protraction increased the activations of the muscles surrounding the shoulder joint and improved the function of the upper extremity.

The Effects of Abdominal Hollowing in Lower-limb PNF Pattern Training on the Activation of Contralateral Muscles.

[Purpose] The purpose of this study was to determine the effects of abdominal hollowing during lower-limb proprioceptive neuromuscular facilitation (PNF) training on the activation of contralateral muscles. [Subjects] Twenty male college students without symptoms or signs of muscular or nervous disease participated in this experiment after signing a consent form. [Methods] All the subjects were measured with electromyography (EMG) in a muscle activation test before and after abdominal hollowing. In the PNF program, the lower-limb pattern of PNF training, was maintained for 5 seconds, followed by a 2-minute break. This was repeated three times. The resting time between sets was 30 minutes. Surface EMG (Keypoint, Medtronic Inc., USA) was used for the measurements, and the highest value of three measurements was used in the analysis. [Result] The results revealed a significant change in the muscular activation of the opposite-side lower limbs. The muscular activations of the vastus lateralis, tibialis anterior, semitendinosus and gastrocnemius were increased significantly after the abdominal hollowing. [Conclusion] The findings suggest that abdominal hollowing in PNF pattern training can be effective at promoting muscular activation of the contralateral muscles. To promote muscular activation of the opposite side in lower-limb PNF pattern training, abdominal hollowing should be considered to improve the effect of PNF pattern training.