The Effect of Pelvic Tilt on Muscle Activity of Cervical Erector Spinae & Upper Trapezius While Using a Smartphone

2017 ◽  
Vol 7 (4) ◽  
pp. 97-103 ◽  
Author(s):  
Seong-In Song ◽  
◽  
Jong-Ho Kang
2017 ◽  
Vol 32 (3) ◽  
pp. 125-131 ◽  
Author(s):  
VAE Baadjou ◽  
MDF van Eijsden-Besseling ◽  
JAMCF Verbunt ◽  
RA de Bie ◽  
RPJ Geers ◽  
...  

Musculoskeletal complaints are highly prevalent in clarinetists and are related to high arm load while playing. It is hypothesized that postural exercise therapy may be used to adapt muscle activity patterns while playing and thus contribute to better sound quality. The goal of the present study was to investigate the relationship between body posture, muscle activity, and sound quality in clarinetists while playing the instrument in two different postures, their habitual sitting posture (control, CO) vs an experimental sitting posture (EXP) based on Mensendieck postural exercise therapy, method Samama. Twenty healthy professional and student clarinet players, aged 18–60 years, were included in this cross-sectional study. Participants played a 60-second musical excerpt in CO, followed by instruction on the EXP body posture, and then played in the EXP condition. Two-dimensional goniometric analysis was used to calculate body posture; muscle activity was measured bilaterally using surface electromyography. In EXP, a significantly smaller low thoracic angle, smaller high thoracic angle, and larger pelvic tilt angle (all p<0.001) were found. EMG results indicated that the left and right erector spinae L3 and left and right lower trapezius were more active in EXP compared to CO, whereas left upper trapezius and right brachioradialis were less active in EXP than CO. Most participants experienced better sound quality in EXP, whereas blinded experts found no consistent pattern between body posture and sound quality. To conclude, it seems that postural exercise therapy may change muscle activity patterns. By increasing stability, a decrease in activity of the upper extremity muscles can be induced.


Author(s):  
Amanda M. Farias Zuniga ◽  
Julie N. Côté

Objective: The effects of performing a 90-minute computer task with a laptop versus a dual monitor desktop workstation were investigated in healthy young male and female adults. Background: Work-related musculoskeletal disorders are common among computer (especially female) users. Laptops have surpassed desktop computer sales, and working with multiple monitors has also become popular. However, few studies have provided objective evidence on how they affect the musculoskeletal system in both genders. Methods: Twenty-seven healthy participants (mean age = 24.6 years; 13 males) completed a 90-minute computer task while using a laptop or dual monitor (DualMon) desktop. Electromyography (EMG) from eight upper body muscles and visual strain were measured throughout the task. Neck proprioception was tested before and after the computer task using a head-repositioning test. EMG amplitude (root mean square [RMS]), variability (coefficients of variation [CV]), and normalized mutual information (NMI) were computed. Results: Visual strain ( p < .01) and right upper trapezius RMS ( p = .03) increased significantly over time regardless of workstation. Right cervical erector spinae RMS and cervical NMI were smaller, while degrees of overshoot (mean = 4.15°) and end position error (mean = 1.26°) were larger in DualMon regardless of time. Effects on muscle activity were more pronounced in males, whereas effects on proprioception were more pronounced in females. Conclusion: Results suggest that compared to laptop, DualMon work is effective in reducing cervical muscle activity, dissociating cervical connectivity, and maintaining more typical neck repositioning patterns, suggesting some health-protective effects. Application: This evidence could be considered when deciding on computer workstation designs.


Author(s):  
Yong-Ku Kong ◽  
Chae-Won Park ◽  
Min-Uk Cho ◽  
Seoung-Yeon Kim ◽  
Min-Jung Kim ◽  
...  

The aim of this study was to evaluate the muscle activities and subjective discomfort according to the heights of tasks and the lower-limb exoskeleton CEX (Chairless EXoskeleton), which is a chair-type passive exoskeleton. Twenty healthy subjects (thirteen males and seven females) participated in this experiment. The independent variables were wearing of the exoskeleton (w/ CEX, w/o CEX), working height (6 levels: 40, 60, 80, 100, 120, and 140 cm), and muscle type (8 levels: upper trapezius (UT), erector spinae (ES), middle deltoid (MD), triceps brachii (TB), biceps brachii (BB), biceps femoris (BF), rectus femoris (RF), and tibialis anterior (TA)). The dependent variables were EMG activity (% MVC) and subjective discomfort rating. When wearing the CEX, the UT, ES, RF, and TA showed lower muscle activities at low working heights (40–80 cm) than not wearing the CEX, whereas those muscles showed higher muscle activities at high working heights (100–140 cm). Use of the CEX had a positive effect on subjective discomfort rating at lower working heights. Generally, lower discomfort was reported at working heights below 100 cm when using the CEX. At working heights of 100–140 cm, the muscle activity when wearing the CEX tended to be greater than when not wearing it. Thus, considering the results of this study, the use of the lower-limb exoskeleton (CEX) at a working height of 40–100 cm might reduce the muscle activity and discomfort of whole body and decrease the risk of related disorders.


Work ◽  
2021 ◽  
pp. 1-13
Author(s):  
Minghao Tang ◽  
Carolyn M. Sommerich ◽  
Steven A. Lavender

BACKGROUND: Neck discomfort and pronounced neck flexion have been associated with smartphone use. OBJECTIVE: Eye glasses with a 90 deg prism in each lens were investigated as a potential intervention to reduce awkward head and neck postures during activities involving viewing the device. METHODS: Sixteen smartphone users with neck pain and 9 asymptomatic users performed a texting task on a smartphone with and without the prism glasses, in sitting and standing postures in a laboratory setting. RESULTS: Cervical erector spinae and upper trapezius muscle activity, head posture and motion, performance, discomfort and other subjective perceptions were assessed. Prism glasses reduced neck extensor muscle activity, neck flexion, and head tilt compared to the direct view. In the symptomatic group, the intervention produced less neck and shoulder discomfort compared to the direct view. CONCLUSIONS: This intervention could offer an alternative way of interacting with a smartphone while texting in stationary postures, by reducing exposure to pronounced flexed neck and head posture commonly seen in users, and thereby could reduce neck discomfort associated with smartphone use.


Author(s):  
Sun-Hee Ahn ◽  
Sung-Hoon Jung ◽  
Hyun-A Kim ◽  
Jun-Hee Kim ◽  
Young-Soo Weon ◽  
...  

BACKGROUND: Due to the extended use of smartphones, people spend a lot of time on these devices while lying down. OBJECTIVE: The purpose of the present study was to compare the differences in neck muscle activity of participants while they watched videos on a smartphone in four different lying positions (supine (SUP), prone on elbows (PE), side lying (SIDE), and 45∘ head turn while side lying (45-SIDE)). METHODS: Twenty-three healthy volunteers (22.4 ± 1.7 years) were enrolled in this study. We assessed the activities of their right and left sternocleidomastoid (SCM), anterior scalene, cervical erector spinae (CES), and upper trapezius (UT) muscles while they watched videos on a smartphone in four different lying positions. RESULTS: The right and left SCM and CES had significantly different muscle activities depending on the lying positions. The SCM activity had a significantly greater asymmetry in the 45-SIDE position, while the CES activity had a significantly greater asymmetry in the SIDE and 45-SIDE positions. Moreover, the UT activity had a significantly greater asymmetry in the SUP, PE, and SIDE positions. CONCLUSIONS: Neck muscle activity and asymmetry were the lowest in the SUP position relative to the other positions. Therefore, lying down in the SUP position may minimize neck muscle activation while using a smartphone.


2002 ◽  
Vol 16 (2) ◽  
pp. 92-96
Author(s):  
Tiina Ritvanen ◽  
Reijo Koskelo ◽  
Osmo H„nninen

Abstract This study follows muscle activity in three different learning sessions (computer, language laboratory, and normal classroom) while students were studying foreign languages. Myoelectric activity was measured in 21 high school students (10 girls, 11 boys, age range 17-20 years) by surface electromyography (sEMG) from the upper trapezius and frontalis muscles during three 45-min sessions. Root mean square (RMS) average from both investigated muscles was calculated. The EMG activity was highest in both muscle groups in the computer-aided session and lowest in the language laboratory. The girls had higher EMG activity in both investigated muscle groups in all three learning situations. The measured blood pressure was highest at the beginning of the sessions, decreased within 10 min, but increased again toward the end of the sessions. Our results indicate that the use of a computer as a teaching-aid evokes more constant muscle activity than the traditional learning situations. Since muscle tension can have adverse health consequences, more research is needed to determine optimal classroom conditions, especially when technical aids are used in teaching.


Author(s):  
Sang-Yeol Lee ◽  
Se-Yeon Park

BACKGROUND: Recent clinical studies have revealed the advantages of using suspension devices. Although the supine, lateral, and forward leaning bridge exercises are low-intensity exercises with suspension devices, there is a lack of studies directly comparing exercise progression by measuring muscular activity and subjective difficulty. OBJECTIVE: To identify how the variations in the bridge exercise affects trunk muscle activity, the present study investigated changes in neuromuscular activation during low-intensity bridge exercises. We furthermore explored whether the height of the suspension point affects muscle activation and subjective difficulty. METHODS: Nineteen asymptomatic male participants were included. Three bridge exercise positions, supine bridge (SB), lateral bridge (LB), forward leaning (FL), and two exercise angles (15 and 30 degrees) were administered, thereby comparing six bridge exercise conditions with suspension devices. Surface electromyography and subjective difficulty data were collected. RESULTS: The rectus abdominis activity was significantly higher with the LB and FL exercises compared with the SB exercise (p< 0.05). The erector spinae muscle activity was significantly higher with the SB and LB exercises, compared with the FL exercise (p< 0.05). The LB exercise significantly increased the internal oblique muscle activity, compared with other exercise variations (p< 0.05). The inclination angle of the exercise only affected the internal oblique muscle and subjective difficulty, which were significantly higher at 30 degrees compared with 15 degrees (p< 0.05). CONCLUSIONS: Relatively higher inclination angle was not effective in overall activation of the trunk muscles; however, different bridge-type exercises could selectively activate the trunk muscles. The LB and SB exercises could be good options for stimulating the internal oblique abdominis, and the erector spinae muscle, while the FL exercise could minimize the erector spinae activity and activate the abdominal muscles.


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