Effect of Cellular Phone Weight on the Muscle Recruitment in Neck and Upper Extremity

Jangwhon Yoon,Heonseock Cynn,Kisong Kim 대한인간공학회 2013 대한인간공학회 학술대회논문집 Vol.2013 No.5

Objective: The aim of this study was to understand the effects of phone weight on the muscle recruitment in the neck and upper extremity while texting a message with one hand. Background: Too much use of a cellular phone can lead the musculoskeletal disorders in the neck and upper extremity. Phone makers tend to make their new models bigger, lighter, faster and smarter. Method: Fourteen healthy volunteers without any history of neuromuscular disorders or ongoing pain who used their smart phone more than one year were recruited. A 112g phone (iphone5) and a 142g phone (iphone4) were used for texting the lyric of the Korean national anthem with their dominant hand. Muscle recruitment of neck (middle trapezius and levator scapula), shoulder (infraspinatus and mid deltoid), elbow (biceps brachii and brachioradialis), thumb (extensor and abductor policis brevis) was collected using surface electromyography. Typing error was counted and typing speed was calculated in characters per min. The data were analyzed using the repeated measures ANOVA for the effects of phone weight on the posture, muscle recruitment and typing error and speed. Results: The result is under analysis for further detail. Conclusion: Typing text message with iPhone5 took longer but had less muscle recruitment in brachioradialis, and extensor and abductor policis brevis muscles. Application: Findings of this study can be valuable information for phone designers to develop more productive device and for smart phone users to prevent the musculoskeletal disorders in the upper extremities.

Combined Effects of Gastrocnemius Stretch and Tibialis Anterior Resistance Exercise in Subjects with Limited Ankle Dorsiflexion

Jihyun Lee,Heonseock Cynn,Areum Shin,Bobeen Kim 물리치료재활과학회 2021 Physical therapy rehabilitation science Vol.10 No.1

Objective: Limited ankle dorsiflexion is related to ankle injuries. There are various exercises to increase the flexibility of the gastrocnemius for improving the passive range of motion in ankle dorsiflexion. However, to performances in daily activities and athletic sports and higher efficiency of walking and running, both ankle dorsiflexion passive and active range of motion are needed. To investigate the effects of combined gastrocnemius stretching and tibialis anterior resistance exercise on ankle kinematics (passive and active range of motion of ankle dorsiflexion) and tibialis anterior muscle activity in subjects with limited ankle dorsiflexion. Design: Cross-sectional single-group repeated measures design. Methods: Fourteen subjects with limited ankle dorsiflexion were recruited (in the right ankle in 7 and the left ankle in 7). All subjects performed gastrocnemius stretching alone and tibialis anterior resistance exercise after gastrocnemius stretching. The passive and active range of motion of ankle dorsiflexion were measured after interventions immediately. The tibialis anterior activity was measured during active range of motion of ankle dorsiflexion measurement. Results: There was no significant difference of ankle dorsiflexion passive range of motion between gastrocnemius stretching alone and the tibialis anterior resistance exercise after gastrocnemius stretching. The tibialis anterior resistance exercise after gastrocnemius stretching significantly increased active range of motion of ankle dorsiflexion compared to gastrocnemius stretching alone (p<0.05). The tibialis anterior resistance exercise after gastrocnemius stretching significantly increased tibialis anterior activity better than did gastrocnemius stretching alone. Conclusions: Thus, subjects with limited ankle dorsiflexion should be encouraged to perform tibialis anterior resistance exercises.

Effect of Smartphone Typing on the Muscle Recruitment in Neck and Upper Extremity

Jangwhon Yoon,Taelim Yoon,Heonseock Cynn,Kisong Kim 대한인간공학회 2013 대한인간공학회 학술대회논문집 Vol.2013 No.10

Background: Too much use of a smartphone can lead the musculoskeletal disorders in the neck and upper extremity. People spend more time in typing on it than using it as a phone. Objective: The aims of this study were to test which way we can type faster and better, and to understand the muscle recruitment in the neck and upper extremity while texting identical messages with one hand and two hands, and put the phone vertically and horizontally. Method: Fourteen healthy college students without any history of neuromuscular disorders or ongoing pain who used the smart phone more than one year were recruited. An iphone4 were used for texting the lyric of the Korean national anthem(79 characters with space) with one hand (dominant side) and two hands and put the phone vertically and horizontally. Muscle recruitment of neck (levator scapuare and middle trapezius), shoulder (infraspinatus and mid deltoid), elbow(biceps, brachioradialis), wrist (flexor and extensor carpi radialis), thumb (extensor and abductor policis, dorsal interossei) was collected with an electromyography system. The data were analyzed using the repeated measures ANOVA. Results: Typing with one hand took longer but not twice longer. After typing with one hand, more fatigue was reported. Placing the phone vertically or horizontally did not affect the typing speed. Typing error were less with two hand and with horizontally placed phone but not statistically significant. Less muscle activities were found in elbow and thumb with one hand use and in the neck with horizontally located phone. Application: Findings of this study can be valuable information for smartphone users to prevent the musculoskeletal disorders in the upper extremities.

Effects of Aquatic Exercise on Upper Extremity Function and Postural Control During Reaching in Children With Cerebral Palsy

Jeon Yongjin,Jeon Hye-Seon,Yi Chung-hwi,Kwon Oh-yun,Cynn Heonseock,Oh Duckwon 한국전문물리치료학회 2023 한국전문물리치료학회지 Vol.30 No.2

Background: Despite the fact that aquatic exercise is one of the most popular alternative treatment methods for children with cerebral palsy (CP), there are few research regarding its effectiveness. Objects: The purpose of this study was to examine the effects of aquatic exercise on upper extremity function and postural control during reaching in children with CP. Methods: Ten participants (eight males and two females; 4–10 years; Gross Motor Function Classification System levels II–IV) with spastic diplegia were recruited to this study. The aquatic exercise program consisted of four modified movements that were selected from the Halliwick 10-point program to enhance upper extremity and trunk movements. The participants attended treatment two times a week for 6 weeks, averaging 35 minutes each session. The Box and Block Test (BBT), transferring pennies in the Bruininks-Oseretsky Test (BOT), and pediatric reaching test (PRT) scores were used as clinical measures. Three-dimensional motion analysis system was used to collect and analyze kinematic data. Differences in BBT and BOT values among pre-treatment, post-treatment, and retention (after 3 weeks) were analyzed using a Friedman test. In addition, the PRT scores and variables (movement time, hand velocity, straightness ratio, and number of movement units) from the three-dimensional motion analysis were tested using a Wilcoxon signed-rank test. The significance level was established at p < 0.05. When the results appeared to be statistically significant, a post-hoc test for multiple comparisons was performed with the Wilcoxon signed-rank test. Results: All clinical measures, which included BBT, transferring pennies of BOT, and PRT, were significantly increased between pre-intervention and post-intervention scores and between pre-intervention and retention scores after treatment (p = 0.001). Three-dimensional motion analysis mostly were significantly improved after treatment (p = 0.001). Conclusion: Aquatic exercise may help to improve body function, activity, and participation in children with varying types of physical disabilities.