A comparison of posture and muscle activity during tablet computer, desktop computer and paper use by young children

Computers are now widely used by children. Tablet computers are becoming widely available and promoted for use by school children. The primary objective of this study was to compare the posture and muscle activity of children using a tablet computer to the posture and muscle activity of children using a desktop computer and paper technology. Eighteen children (mean age 5.6 years) performed a colouring-in task in tablet, desktop and paper conditions. 3-D posture and muscle activity around the neck and shoulder was assessed. Tablet computer use was similar to paper use, with less neutral spinal posture, more elevated scapular posture and greater upper trapezius and cervical erector spinae activity. This was offset by greater variability of posture and muscle activity. Tablet computer use clearly results in different musculoskeletal stresses than desktop computer use. Computer use guidelines need to be appropriate to traditional and emerging technologies. Tablet computers are being promoted for use by adults and children. However, the physical impact of using this type of technology is not known. The findings of this study provide the first tablet-specific evidence to inform guidelines on wise use of tablet computers by children.     

Children's posture and muscle activity at different computer display heights and during paper information technology use

OBJECTIVE: The 3-D posture and muscle activity in the neck and upper limb were assessed in children using high-, mid-, and book-level displays, which correspond to working conditions frequently observed when children interact with computers or books and paper. BACKGROUND: The 3-D posture and muscle activity of children reading and inputting data with computers and paper had not been previously assessed. METHODS: Twenty-four children aged 10 to 12 years and of normal height performed an interactive task involving reading from a book and writing on paper or reading from a computer display and inputting data using a mouse and keyboard. RESULTS: Head and neck flexion increased as the visual target was lowered. The high display resulted in mainly upper cervical relative extension, and the book display resulted in both upper and lower cervical flexion. The book condition resulted in greater cervical erector spinae and upper trapezius activity than did the mid and high conditions. CONCLUSION: The data suggest that a mid-level display may be more appropriate for children than a high display (e.g., when the display is placed on top of the central processing unit). The mid display also results in a more upright and symmetrical posture and lower mean muscle activity than does working with books and paper flat on the desk. APPLICATION: This study provides short-term laboratory study evidence for the formulation of guidelines for workstation design and adjustment for children. Use of computers by children is increasing, yet ergonomic guidelines lag behind those for adults.     

Gravitational demand on the neck musculature during tablet computer use

Tablet computer use requires substantial head and neck flexion, which is a risk factor for neck pain. The goal of this study was to evaluate the biomechanics of the head–neck system during seated tablet computer use under a variety of conditions. A physiologically relevant variable, gravitational demand (the ratio of gravitational moment due to the weight of the head to maximal muscle moment capacity), was estimated using a musculoskeletal model incorporating subject-specific size and intervertebral postures from radiographs. Gravitational demand in postures adopted during tablet computer use was 3–5 times that of the neutral posture, with the lowest demand when the tablet was in a high propped position. Moreover, the estimated gravitational demand could be correlated to head and neck postural measures (0.48 < R ² < 0.64, p < 0.001). These findings provide quantitative data about mechanical requirements on the neck musculature during tablet computer use and are important for developing ergonomics guidelines.

Practitioner Summary: Flexed head and neck postures occur during tablet computer use and are implicated in neck pain. The mechanical demand on the neck muscles was estimated to increase 3–5 times during seated tablet computer use versus seated neutral posture, with the lowest demand in a high propped tablet position but few differences in other conditions.     

Physical exposure differences between children and adults when using standard and small computer input devices

By the age of five years, 75% of the children in the USA are using computers and at this age they are only one-half to two-thirds the size of and about one-fifth as strong as their adult counterparts. Fourteen children between five and eight years of age and their same-gender biological parents (giving a total of 28 subjects) were evaluated using both a standard and a smaller, child-proportional input device during standardised mouse and keyboard tasks. Typing and computer mouse performance were measured with tracking software, wrist posture was measured with an electrogoniometer and electromyography was used to measure finger flexor and extensor muscle activity in the right arm. With the small mouse, both children and adults performed the mouse task significantly faster and made significantly fewer errors. When using the standard-sized mouse and keyboard, children worked with significantly greater ulnar deviation and significantly less extension than their adult counterparts. When children used the smaller mouse, finger flexor muscle activity, finger extensor muscle activity and ulnar deviation significantly decreased, with little change in wrist extension compared to the standard mouse. No significant differences were observed between the standard and small keyboards for children or their parents. Compared to their adult counterparts, children had to apply twice the relative force, as a percentage of their maximum capacity, to activate the buttons and keys on the input devices. These measured differences may have application in the design of computer input devices for children.     

The influence of desk and display design on posture and muscle activity variability whilst performing information technology tasks

Desk design and computer display height can affect posture and muscle activation during computer use. Amplitudes of postural variables and muscle activity during computer use do not explain the results from epidemiological studies of musculoskeletal discomfort and disorders related to computer use. The purpose of this study was to assess variability of posture and muscle activity during work with two computer display heights and book/paper, in conjunction with a curved desk designed to provide forearm support and a traditional, straight desk.18 male and 18 female participants performed 10-min tasks involving keying, mousing, reading and writing in six desk/display conditions. 3D posture and surface emg were assessed for the final 2 min of each task.The curved desk resulted in greater postural and muscle activity variation, suggesting an advantage of this supportive surface over the straight desk. There was little difference in variability associated with the two display heights. However, greater variability of posture and muscle activity was evident with the book/paper condition. Non-touch typists had greater neck flexion variation.The design of information technology tasks and workstations can influence the short term variation in posture and muscle activity. Variation is influenced independently of mean postures and muscle amplitudes and therefore needs to be considered to adequately assess the risk of musculoskeletal disorders.     

Physical exposure differences between children and adults when using standard and small computer input devices

By the age of five years, 75% of the children in the USA are using computers and at this age they are only one-half to two-thirds the size of and about one-fifth as strong as their adult counterparts. Fourteen children between five and eight years of age and their same-gender biological parents (giving a total of 28 subjects) were evaluated using both a standard and a smaller, child-proportional input device during standardised mouse and keyboard tasks. Typing and computer mouse performance were measured with tracking software, wrist posture was measured with an electrogoniometer and electromyography was used to measure finger flexor and extensor muscle activity in the right arm. With the small mouse, both children and adults performed the mouse task significantly faster and made significantly fewer errors. When using the standard-sized mouse and keyboard, children worked with significantly greater ulnar deviation and significantly less extension than their adult counterparts. When children used the smaller mouse, finger flexor muscle activity, finger extensor muscle activity and ulnar deviation significantly decreased, with little change in wrist extension compared to the standard mouse. No significant differences were observed between the standard and small keyboards for children or their parents. Compared to their adult counterparts, children had to apply twice the relative force, as a percentage of their maximum capacity, to activate the buttons and keys on the input devices. These measured differences may have application in the design of computer input devices for children.     

Muscle Activity and Comfort Perception on Neck,Shoulder, and Forearm While Using a Tablet Computer at Various Tilt Angles

Tablet computers have become ubiquitous. There is a serious risk that using tablets may lead to musculoskeletal disorders. This research aims to investigate, for tablet computer users, the musculature load and comfort perception of the engaged upper extremity for three angles of viewing and common task types performed at a computer workstation. Thirty healthy adults were recruited. A 3 × 2 repeated experimental design with tilt angle (22.5°, 45°, and 67.5° from horizontal) and task type (movie watching vs. game playing) was employed. The muscular activity of the upper extremity was assessed by electromyography measurement. Subjective comfort ratings were collected using the visual analogue scale. The results showed that when tablets were mounted at a high tilt angle (67.5°), neck muscle activity was low; however, when the tablet computer was mounted at a low tilt angle (22.5°), shoulder forward flexion activity was low, particularly during the game-playing task. This article suggests that users who feel musculoskeletal discomfort in the neck area increase the angle of their tablet computers to decrease neck stress and that users who have musculoskeletal discomfort in the shoulder area position the tablet computer at a lower tilt angle to decrease shoulder stress.     

Principles for the wise use of computers by children

Computer use by children at home and school is now common in many countries. Child computer exposure varies with the type of computer technology available and the child's age, gender and social group. This paper reviews the current exposure data and the evidence for positive and negative effects of computer use by children. Potential positive effects of computer use by children include enhanced cognitive development and school achievement, reduced barriers to social interaction, enhanced fine motor skills and visual processing and effective rehabilitation. Potential negative effects include threats to child safety, inappropriate content, exposure to violence, bullying, Internet ‘addiction’, displacement of moderate/vigorous physical activity, exposure to junk food advertising, sleep displacement, vision problems and musculoskeletal problems. The case for child specific evidence-based guidelines for wise use of computers is presented based on children using computers differently to adults, being physically, cognitively and socially different to adults, being in a state of change and development and the potential to impact on later adult risk. Progress towards child-specific guidelines is reported. Finally, a set of guideline principles is presented as the basis for more detailed guidelines on the physical, cognitive and social impact of computer use by children. The principles cover computer literacy, technology safety, child safety and privacy and appropriate social, cognitive and physical development. The majority of children in affluent communities now have substantial exposure to computers. This is likely to have significant effects on child physical, cognitive and social development. Ergonomics can provide and promote guidelines for wise use of computers by children and by doing so promote the positive effects and reduce the negative effects of computer–child, and subsequent computer–adult, interaction.     

Upper quadrant postural changes of school children in response to interaction with different information technologies

The objective of this study was to quantitatively analyse the sitting posture of school children interacting with both old (book) and new (laptop and desktop computers) information technologies to test the hypothesis that posture is effected by the type of information technology (IT) used. A mixed model design was used to test the effect of IT type (within subjects) and age and gender (between subjects). The sitting posture of 32 children aged 4-17 years was measured whilst they read from a book, laptop, and desktop computer at a standard school chair and desk. Video images were captured and then digitized to calculate mean angles for head tilt, neck flexion, trunk flexion, and gaze angle. Posture was found to be influenced by IT type (p < 0.001), age (p < 0.001) and gender (p = 0.024) and significantly correlated to the stature of the participants. Measurement of resting posture and the maximal range of motion of the upper and lower cervical spines in the sagittal plane was also undertaken. The biophysical impact and the suitability of the three different information technologies are discussed.     

An investigation of children's posture and discomfort during computer use

This study investigated schoolchildren's posture and discomfort while working at computers. Sixty-eight children (mean age 9.5 years) were observed at school during normal computer sessions lasting 15-25 min. Rapid upper limb assessment (RULA) was used to evaluate posture, and a body discomfort chart (BDC) and a modified visual analogue scale (VAS) were used to record site and intensity of discomfort. Computer tasks were noted and in accordance with RULA, postures were classified as Action Level (AL) 1 (acceptable) to 4 (needs immediate change). Most children adopted postures at an unacceptable level while working at computers. None of the postures were in AL 1; 60% were in AL 2; 38% were in AL 3; and 2% were in AL 4. Posture became worse over time. Poor posture was associated with discomfort, but it is not clear if it was related to the sitting posture or to the computer use. Children who reported discomfort had a higher mean RULA grand score (5.0) than those who did not report discomfort (4.4). The type of computer task influenced the children's posture. RULA proved generally to be a suitable method for evaluating children's posture.     

User discomfort, work posture and muscle activity while using a touchscreen in a desktop PC setting

An experimental study was conducted to evaluate physical risk factors associated with the use of touchscreen in a desktop personal computer (PC) setting. Subjective rating of visual/body discomfort, shoulder and neck muscle activity, elbow movement and user-preferred positions of the workstation were quantified from 24 participants during a standardised computer use task with a standard keyboard and a mouse (traditional setting), with a touchscreen and the standard keyboard (mixed-use condition) and with the touchscreen only. The use of a touchscreen was associated with a significant increase of subjective discomfort on the shoulder, neck and fingers, myoelectric activity of shoulder and neck muscles and percentage of task duration that arms were in the air. Participants placed the touchscreen closer and lower when using touch interfaces compared with the traditional setting. Results suggest that users would need more frequent breaks and proper armrests to reduce physical risks associated with the use of a touchscreen in desktop PC settings. Statement of Relevance: In this study, subjective discomfort, work posture and muscle activity of touchscreen desktop PC users were quantitatively evaluated. The findings of this study can be used to understand potential risks from the use of a touchscreen desktop PC and to suggest design recommendations for computer workstations with the touchscreen.     

User discomfort,work posture and muscle activity while using a touchscreen in a desktop PC setting

An experimental study was conducted to evaluate physical risk factors associated with the use of touchscreen in a desktop personal computer (PC) setting. Subjective rating of visual/body discomfort, shoulder and neck muscle activity, elbow movement and user-preferred positions of the workstation were quantified from 24 participants during a standardised computer use task with a standard keyboard and a mouse (traditional setting), with a touchscreen and the standard keyboard (mixed-use condition) and with the touchscreen only. The use of a touchscreen was associated with a significant increase of subjective discomfort on the shoulder, neck and fingers, myoelectric activity of shoulder and neck muscles and percentage of task duration that arms were in the air. Participants placed the touchscreen closer and lower when using touch interfaces compared with the traditional setting. Results suggest that users would need more frequent breaks and proper armrests to reduce physical risks associated with the use of a touchscreen in desktop PC settings.

Statement of Relevance: In this study, subjective discomfort, work posture and muscle activity of touchscreendesktop PC users were quantitatively evaluated. The findings of this study can be used to understand potential risksfrom the use of a touchscreen desktop PC and to suggest design recommendations for computer workstations with the touchscreen.     

The concept and correlates of computer anxiety

The introduction of computers into the lives and workplaces of many individuals represents a dramatic change. Zuboff has used the term 'computer-mediated' work to describe how the increasingly intellectual nature of work and the availability of computers is creating a revolution in the workplace. There is a real concern about how individuals react both cognitively and emotionally to the introduction of computer technology. The growth of the end-user computing phenomenon has made this concern more acute. Although many individuals have little difficulty using computers, there remains a far larger population of users who experience considerable difficulty learning how to use computer systems. Computer anxiety is a widely occurring phenomenon for this group of users, whose job performance and success may depend on their interaction with computers. Reviewing the literature, this paper describes the nature and correlates of computer anxiety and assesses training as a mechanism for reducing the impact of this anxiety. Limitations in current knowledge are noted and suggestions for further research are described.     

Upper quadrant postural changes of school children in response to interaction with different information technologies

The objective of this study was to quantitatively analyse the sitting posture of school children interacting with both old (book) and new (laptop and desktop computers) information technologies to test the hypothesis that posture is effected by the type of information technology (IT) used. A mixed model design was used to test the effect of IT type (within subjects) and age and gender (between subjects). The sitting posture of 32 children aged 4?–?17 years was measured whilst they read from a book, laptop, and desktop computer at a standard school chair and desk. Video images were captured and then digitized to calculate mean angles for head tilt, neck flexion, trunk flexion, and gaze angle. Posture was found to be influenced by IT type (p?<?0.001), age (p?<?0.001) and gender (p?=?0.024) and significantly correlated to the stature of the participants. Measurement of resting posture and the maximal range of motion of the upper and lower cervical spines in the sagittal plane was also undertaken. The biophysical impact and the suitability of the three different information technologies are discussed.     

Preparing Malaysian vocational and technology teachers to integrate computer technology in teaching vocational and technology subjects

A study was conducted in three selected states in Malaysia to determine the preparedness of vocational and technology teachers to integrate computer technology in their classrooms. The study showed that teachers did not have a high level of general knowledge about computers (mean=6.3, sd.=2.97). They were not very knowledgeable in some computer software. They thought that they were not skillful in using computer software such as electronic spreadsheet (57.1%), word-processing and desktop publishing (50.8%), and database management (67.9%). Almost two-thirds of the respondents cannot do programming. Realizing that they did not have the necessary knowledge and skills, the majority of the teachers would like to attend training in using computers for instruction.     

Neck/shoulder pain,habitual spinal posture and computer use in adolescents: the importance of gender

Neck/shoulder pain is a common complaint, with evidence suggesting rates in adolescence have increased in line with increased computer use. The study aimed to examine the influence of gender on relationships between computer use, habitual posture and neck/shoulder pain. Adolescents (n = 1483) participating in the 14 year follow-up of the Raine Study cohort were surveyed for computer use, habitual sitting posture and neck/shoulder pain. Females used computers less than males (52% vs. 45% used for up to 7 h per week). Females sat much more upright than males with greater anterior pelvic tilt (9.4° vs. 0.4°). Females reported a higher 1 month prevalence of neck/shoulder pain (34.7%) than males (23.1%). A multivariate model showed neck/shoulder pain risk was increased in females (OR 2.61, 95% CI 1.70–4.00) and with computer use (OR 1.19, CI 1.01–1.40). Computer use is related to neck/shoulder pain and posture in adolescents but this relationship is different in boys and girls.

Statement of Relevance: This study showed the confounding effect of gender on the relationships among computer use, posture and neck/shoulder pain and thus the need to consider genders separately in research and practice aiming to optimise young people's use of computers.     

Gender,Internet and computer attitudes and experiences

It is widely assumed that participation by females on the Internet is hampered by their attitudes towards computers, which in turn is reflective of their attitudes towards new technology. Research generally supports that females have less overall experience with computers and are more likely than males to have negative attitudes towards computers. Although limited, research on Internet experiences and attitudes has found parallel gender differences, with females reporting lower levels of experience and more negative attitudes. This paper explores whether Internet and computer experiences, skills and attitudes are related, using evidence from two studies of incoming college students, in 1989/90 and 1997. There were significant gender differences in many computer experiences and attitudes of incoming students in 1989/90. Males were more experienced with computers, more likely to have taken high school courses requiring computer use, and reported higher skill levels in applications such as programming, games and graphics than females. By 1997, incoming students were more experienced with using a computer than the earlier students. However, gender differences in computer experience and skill levels had diminished in some areas. The 1997 survey also assessed Internet experiences, skills, competence and comfort. Students had more exposure to computers than to the Internet. Males were more experienced and reported higher skill levels with the Internet than females, with the exception of e-mail. The overall competency and comfort level for students in 1997 was significantly higher for computers than for the Internet; 19% of the students did not feel competent and/or comfortable with the computer compared to 36% with the Internet, with females reporting higher levels of incompetence and discomfort for both. Competence and comfort levels with the Internet and computers were highly intercorrelated, and both predicted Internet skills and experiences.     

Evidence-based guidelines for the wise use of computers by children: Physical development guidelines

Computer use by children is common and there is concern over the potential impact of this exposure on child physical development. Recently principles for child-specific evidence-based guidelines for wise use of computers have been published and these included one concerning the facilitation of appropriate physical development. This paper reviews the evidence and presents detailed guidelines for this principle. The guidelines include encouraging a mix of sedentary and whole body movement tasks, encouraging reasonable postures during computing tasks through workstation, chair, desk, display and input device selection and adjustment and special issues regarding notebook computer use and carriage, computing skills and responding to discomfort. The evidence limitations highlight opportunities for future research. The guidelines themselves can inform parents and teachers, equipment designers and suppliers and form the basis of content for teaching children the wise use of computers.

Statement of Relevance: Many children use computers and computer-use habits formed in childhood may track into adulthood. Therefore child–computer interaction needs to be carefully managed. These guidelines inform those responsible for children to assist in the wise use of computers.     

Young children’s access and use of computers in family child care and child care centers

Forty eight family child care providers and 37 center-based providers completed surveys about the availability and use of computers for children in their care. In addition, the providers were asked about their attitudes towards technology and their own computer skills. The impact of setting type on computer placement and rules about their use did not differ very much by setting type. Several factors were associated with the amount of time children were reported to use the computers. Overall, it appears that child care providers had developmentally sensitive guidelines for fostering computer use in both child care settings.