scholarly journals Neck muscle activation and head kinematics when using a smartphone while walking

2019 ◽  
Vol 63 (1) ◽  
pp. 957-961 ◽  
Author(s):  
Woojin Yoon ◽  
Hyeseon Han ◽  
Seobin Choi ◽  
Gwanseob Shin
Keyword(s):  
Tilt Angle ◽  
Muscle Activation ◽  
Head Tilt ◽  
Neck Muscle ◽  
Safety Issues ◽  
Activation Level ◽  
Extensor Muscles ◽  
Muscular Load ◽  
Smartphone Use ◽  
The One

Using a smartphone while walking has been common in countries with high smartphone penetration rates. While pedestrian safety issues have been studied frequently, research regarding ergonomics issues such as neck discomfort of smartphone use while walking has been limited. An experimental study was conducted to evaluate the neck muscular load of smartphone use while walking. Twenty-one asymptomatic young smartphone owners conducted one-handed browsing and two-handed texting while walking on a treadmill. Their neck muscle activation level, head and upper back posture were quantified. Compared to when walking upright without using a smartphone, the two smartphone-use tasks demanded 33.3% to 101.8% more activation of the neck extensor muscles. Mean head tilt angles (relative to upright standing) were 28.9° and 36.9° for the one-handed browsing and two-handed texting, respectively. Between the two smartphone tasks, the head tilt angle and the muscle activation level were significantly greater for texting than for browsing. Results indicated that conducting two-handed texting while walking would pose larger muscular load to the neck extensor muscles compared to when conducting one-handed browsing while walking due to the larger head tilt angle.

Neck Muscular Load When Using a Smartphone While Sitting, Standing, and Walking

2020 ◽  
pp. 001872082090423 ◽  
Author(s):  
Woojin Yoon ◽  
Seobin Choi ◽  
Hyeseon Han ◽  
Gwanseob Shin
Keyword(s):  
Muscle Activation ◽  
Myoelectric Activity ◽  
Activation Level ◽  
Extensor Muscles ◽  
Musculoskeletal Problems ◽  
Muscular Load ◽  
Smartphone Use ◽  
Neck Musculature

Objective Myoelectric activity of neck extensor muscles and head kinematic variables, when using a smartphone for one-handed browsing and two-handed texting while sitting, standing, and walking, were evaluated to compare the neck muscular load during these tasks and across the posture conditions. Background There has been limited research on the relation between head-down postures and the muscular load on the neck of smartphone users. Methods Twenty-one asymptomatic young users were asked to perform one-handed browsing and two-handed texting tasks in each of the posture conditions, and the myoelectric activities of the neck extensor muscles, head kinematic variables, and upper back posture were quantified. Results The muscle activation level when using a phone during walking was 21.2% and 41.7% higher than that of sitting and standing on average ( p < .01). Head vertical and angular accelerations were also significantly greater ( p < .01) for walking than for sitting and standing conditions. Between the two conducted tasks, participants flexed their heads more significantly ( p < .01) with higher activation of the neck extensor muscles ( p < .01) when texting as compared to when browsing. Conclusion Results indicate that two-handed texting while walking would be the most physically demanding scenario for neck musculature, and it might be attributable to the dynamics of the head while walking with the head facing downwards. Application These findings can be used to better understand the potential relation between smartphone use and the occurrence of neck musculoskeletal problems and to inform the users of the ergonomic risks of using smartphones while walking.

Reflexive Response of Neck Muscle to Sudden Perturbation after Prolonged Smartphone Use

2021 ◽  
Vol 65 (1) ◽  
pp. 1250-1253
Author(s):  
Eunjee Kim ◽  
Donghyun Song ◽  
Dasom Park ◽  
Hyorim Kim ◽  
Gwanseob Shin
Keyword(s):  
Cervical Spine ◽  
Muscle Activation ◽  
Neck Muscle ◽  
Spinal Stability ◽  
Delayed Onset ◽  
Activation Level ◽  
Before And After ◽  
Smartphone Use ◽  
Head Stability ◽  
Passive Stretch

Prolonged smartphone use induces passive stretch of neck tissues and muscle fatigue, affecting spinal stability and pain. It is necessary to evaluate the effect of smartphone use on the reflexive response to detect the changes in neck tissues and head stability. A laboratory experiment (n=10) was conducted to investigate the reflexive response of neck muscle to perturbation after 30 minutes of smartphone use. Neck extensor muscle activation and its activation timing to perturbation were investigated before and after smartphone use. Head angle and muscle activation level were collected during smartphone use. During smartphone use, muscle activation gradually increased. After smartphone use, neck muscles showed a higher activation level and significantly delayed onset to perturbation. Smartphone use changed the reflexive response of the neck muscle. Further study is needed to investigate the association between smartphone use and neuromuscular changes to the tissues of the cervical spine.

scholarly journals COMPARISON OF NECK MUSCLE ELECTROMYOGRAPHY ACTIVITY IN RESPONSE TO EXTERNAL FORCE BETWEEN STATIC AND DYNAMIC LOADING

2019 ◽  
Vol 19 (04) ◽  
pp. 1850034
Author(s):  
D. W. KAK ◽  
A. R. ANITA ◽  
N. M. NIZLAN ◽  
I. NORMALA ◽  
N. A. ABDUL JALIL ◽  
...  
Keyword(s):  
Dynamic Loading ◽  
Static Loading ◽  
Muscle Activation ◽  
Motor Vehicle ◽  
Neck Muscles ◽  
Motor Vehicle Crash ◽  
Neck Muscle ◽  
Activation Level ◽  
Static And Dynamic Loading ◽  
Head Neck

Understanding the behavior of neck muscles is essential to accurately simulate the human head-neck segment movement especially for low-speed motor vehicle crash situation. Some head-neck mathematical models were designed using neck muscle activation behavior in isometric contraction (static loading) as the properties of neck muscle activation. However, neck muscle activation pattern and strength capability may vary between static and dynamic loading. This study aimed to determine the differences between neck muscle activation level under static and dynamic loading. A neck strength test involving 22 human volunteers was conducted with two different tasks in extension and flexion direction with three different loads. The neck muscle activation level is determined through measuring the electromyography (EMG) responses of selected flexor and extensor muscles using surface bilateral electrode and recorded. The findings showed that neck muscle activation level was significantly greater in dynamic loading than static loading ([Formula: see text]). These implied that more efforts from neck muscles were required to resist against dynamic loading than static loading. Nonetheless, the differences in EMG activities between these two loading conditions progressively decreased when more loads were applied. This study has established an empirical model to describe the relationship between neck muscle activation level and force output for both loading condition in flexion and extension.

Low back muscle activity when using a smartphone while walking

2019 ◽  
Vol 63 (1) ◽  
pp. 1099-1102 ◽  
Author(s):  
Seobin Choi ◽  
Misol Kim ◽  
Eunjee Kim ◽  
Gwanseob Shin
Keyword(s):  
Muscle Activation ◽  
Erector Spinae ◽  
Myoelectric Activity ◽  
Low Back ◽  
Back Muscle ◽  
Muscle Activation Patterns ◽  
Concurrent Use ◽  
Extensor Muscles ◽  
Smartphone Use ◽  
Back Extensor

Concurrent use of a smartphone while walking may influence low back muscle activation patterns due to restricted arm motions, limited trunk rotation and walking with the head in a flexed position. The objective of this study was to quantitatively determine the effects of smartphone use while walking on the level of myoelectric activity of the low back extensor muscles. Fifteen asymptomatic young smartphone users who were familiar with smartphone use while walking participated in this experiment. The electromyography (EMG) of the lumbar erector spinae muscles were collected bilaterally when they were conducting three walking tasks on a treadmill: 1) walking without smartphone use (upright walking); 2) web-browsing while walking; and, 3) texting while walking. Results found that the normalized EMG of the lumbar erector spinae muscles were significantly (p<0.05) greater when using a smartphone while walking as compared to when walking without using the phone. It indicates that using a smartphone while walking could pose larger muscular load to the low back extensor muscles than that of walking without using a phone.

scholarly journals Comparative analysis of methods to identify road sections with high accidents risk: a case study of E67 Estonia–Latvia–Lithuania corridor

2021 ◽  
Vol 334 ◽  
pp. 02001
Author(s):  
Maria Pashkevich ◽  
Anton Pashkevich
Keyword(s):  
Safety Management ◽  
Black Spot ◽  
Core Network ◽  
Baltic States ◽  
Safety Issues ◽  
Baltic Countries ◽  
Efficient Management ◽  
North Eastern ◽  
The One ◽  
The Baltic

E67 road is a strategically important part of a North Sea – Baltic Core Network Corridor, connecting the three Baltic States with Finland, on the one hand, and with North Eastern Poland, on the other. So-called Via Baltica corridor services more than 30 000 vehicles per day being one of the major arteries for transit and heavy good vehicles transport in the region. Annually around 8 000 road accidents with casualties occur in the three Baltic States with more than 500 fatalities a year. Relatively high road safety risk exposure requires more efficient management of infrastructure safety issues. The three Baltic States use either black spot management (BSM) or network safety management (NSM) or a combination of these two approaches to treat dangerous road sections of the network. In this article three methodologies used in the Baltic countries for dangerous road sections and spots identification were described. Quantitative analysis of dangerous sections/spots identified by the three methodologies was performed for the whole Via Baltica corridor to reveal the differences between the methods used.

Changing shape according to strength: Evidence from root allomorphy in Greek

2019 ◽  
Vol 36 (3) ◽  
pp. 553-574 ◽  
Author(s):  
Anthi Revithiadou ◽  
Giorgos Markopoulos ◽  
Vassilios Spyropoulos
Keyword(s):  
The Other ◽  
Activation Level ◽  
Vocabulary Item ◽  
Non Linear ◽  
The One ◽  
Surface Realization

Abstract In this article we examine patterns of root allomorphy in Greek that involve vowel alternations and propose a Generalized Non-linear Affixation (Bermúdez-Otero 2012) analysis according to which these alternations result from the competition between segments that belong, on the one hand, to the vocabulary items of roots and, on the other, to the exponents of functional heads (Voice/Aspect, n). More specifically, we claim that phonological entities have a gradient degree of presence in a structure, that is, are specified with a certain activation strength value underlyingly (Smolensky and Goldrick 2016). As a result, the surface realization of roots is determined by the relevant activation level of the exponents of functional heads they are eventually combined with. From all available exponents, the one that optimally complements the strength value of the vocabulary item of a given root will eventually surface. Our analysis is shown to be theoretically advantageous because it develops a strictly phonological account of allomorphy and, moreover, it captures the attested generalizations without resorting to extensive stem/span listing or to the application of phonologically unrestricted readjustment rules.

scholarly journals Auditory Warnings Invoking Startle Response Cause Faster and More Intense Neck Muscle Contractions Prior to Head Impacts

2019 ◽  
Vol 63 (1) ◽  
pp. 802-806
Author(s):  
Mohammad Homayounpour ◽  
Jonathan D Mortensen ◽  
Andrew S Merryweather
Keyword(s):  
Startle Response ◽  
Muscle Activation ◽  
Startle Stimulus ◽  
Pressure Level ◽  
Neck Muscle ◽  
Head Impacts ◽  
Voluntary Response ◽  
Time Period ◽  
Muscle Activations ◽  
High Pressure Level

High-pressure level and sudden sound, especially during an elevated state of alertness can elicit a startle response. Startle response can induce sudden, intense muscle activations. Some studies have shown that increasing neck muscle activation during impact situations can reduce the risk of concussion and neck injury. This research aimed to study muscle coactivation patterns, contraction latency and the level of muscle activation in startle response compared to the voluntary response. To achieve this goal, a testbed capable of applying impacts to the head in four directions was created. Auditory (115 dB) startle stimulus was delivered and muscle activation measured using sEMG on neck muscles during startle and voluntary responses. We investigated a 1000 ms time period starting at the time that the sound is played to the time at impact. Results indicate that the first muscle activation in startle response is 2.1 times higher, 5.9 times faster and involved more muscles than in a voluntary response.

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