TABLETS AND SMART PHONES

HOW TO MANAGE THEM ERGONOMICALLY AND

PREVENT REPETITIVE STRESS INJURIES.

Death of the Typewriter

Rise of the Computer

• Increase in computer use

• Various aches and pains we now know as WMSDs

• The computer-now slowly got hand held

• Metamorphosed into a tablet, a smart phone

Hand Held Devices

• Significant rise in use compared to PC

• Combined use PC+ Handheld device.

• Increased risk of WMSDs

Objective

• We look at various tablets and smart phone dimensions and its use.

• We explore the postures users assume while using these devices.

• We evaluate the possibilities of WMSDs arising from prolonged use of such postures

• Aim to provide certain guidelines for risk management.

The Tablet

• Tablet sizes across the world vary from 5inch to 11inches (case size)

Operating a Tablet

• Tablets are used by people mainly to watch movies, play games.

• Recently they are increasingly being used for more and more times for long meetings etc.

Tablet Research

• In an article published in Work: A Journal of Prevention, Assessment, and Rehabilitation, on January 15, 2012, Harvard School of Public Health researchers have begun quantifying the ways in which a person’s posture, and also the design of the tablet and its case, affects comfort.

• Fifteen experienced tablet users were in a lab to complete a set of simulated tasks on an Apple iPad2 and a Motorola Xoom.

• All of the volunteers were adults under 40.• Each tablet had a proprietary case that could be adjusted

to prop up the tablet at an angle.

The Experiment

• Users were situated in four postures: – Lap-Hand (tablet held on lap)– Lap-Case (tablet placed on lap in case at its lower

angle setting—15 degrees for the iPad and 45 degrees for the Xoom)

– Table-Case (tablet placed on table with its case at its lower angle setting)

– Table-Movie (tablet placed on table in case at its higher angle setting—73 degrees for the iPad and 63 degrees for the Xoom).

Observations

• While users browsed the Internet, responded to email, played games, and watched a movie, their head and neck posture and gaze angle were measured using an infrared three-dimensional motion analysis system.

• The researchers found that study participants’ heads and necks were in more flexed positions while using the tablets than those typical of desktop or notebook computer users.

• Working for long periods of time with the head slumped forward and the neck flexed can result in neck pain.

• Users held their heads in the most neutral positions when sitting in the Table-Movie configuration.

Operational Analysis

• Tablets are used as a portable device and hence lack a proper operating environment.

• It is subject to awkward postures, awkward viewing angles and improper lighting conditions.

• Different people use tablets of different dimensions and weights.

• These factors promote improper ergonomic postures and over time these could lead to various repetitive stress injuries.

WMSD risk areas-Tablet

• Neck-Cervical radiculopathy• Shoulder-iPad shoulder• Wrist and hands-iPad hands/carpal tunnel

syndrome.• Hands- de Quervain syndrome, a painful affliction

that involves the tendons that move the thumb.• Lower back-pain due to improper posture and

prolapse disc • Hogwarts headache

Prevention

• Use an external keyboard and mouse, that makes the setup look more like a desktop.

• Users should “move more; vary positions as much as possible.

• Use cases that let them keep the device propped on a table at about a 60- to 70- degree angle to prevent neck strain.

• Set the font size larger so that one can read material in the appropriate neutral posture with back and neck in a straight vertical line.

Office use

• Ensure that chairs are adjustable, so users can use tablets with their backs and arms supported.

• Ensure adjustable window blinds and overhead lights with glare preventing baffles are installed in meeting rooms and breakout areas where people are likely to use tablets.

• Equip meeting rooms with accessories (e.g. external keyboards) that can be used by anyone.

• Provide covers to all users to support typing.• Provide any other external aids (stands, docking stations,

external keyboards, etc.) when required or requested for users who use tablets at their desks.

The Smart Phone

Evolution of the mobile phone

• Initial mobile phone in the 70s.

• It evolved rapidly in the last decade.

• From black and white to HD colour devices

• Mini Computer

Multitasking with Smart Phone

• Smart phones are increasingly being used for texting, emailing and browsing the web, with less time spent on “the phone”.

• The posture that is assumed while performing these activities, i.e. using thumbs to type while hunched over a tiny keyboard, is very stressful.

• If performed repeatedly over extended periods of time, it increases the risk of musculoskeletal injury.

Operating a Smart Phone

• Use varies from low of 30mins-high of 500mins /day

• Daily average-10mins-200mins/day• Used mainly as a communication tools (e.g. email,

text messages, instant messaging) this accounted for 44% and 49%

• Although phones are mainly operated by holding in one hand with the thumbs, it does require stability via muscles at the wrist, elbow, shoulder and neck

Operation Analysis of Smart Phone

• A study investigated the relationship between the thumb muscle activity and thumb operating tasks in smartphone. Touch screen with one hand posture.

• The study revealed that demand on first dorsal interosseous (FDI) muscle increases when the thumb taps small buttons and in flexion –extension orientation.

• But the demand on abductor pollicis longus increases in adduction and abduction orientation.

• The study reveals that muscle effort among thumb muscles on a touch screen smartphone varies according to the task, and suggests that the use of small touch buttons should be minimised for better thumb performance.

WMSD risk areas-Smart Phone

• With smart phones, the thumb is the main part used for most operations.

• Dequervains syndrome is a common diagnosis or the now outdated blackberry thumb

• CMC joint arthritis.• Some other WMSDs may also include, Text Neck, shooting

pains down your neck and arm, as well as numbness or tingling in your fingers and hand.

• Carpal tunnel syndrome. CTS (although there isn’t much evidence to suggest smart phone use can cause CTS, it can surely aggravate any existing condition.

Prevention

• Draft briefer messages.• Use word recognition to reduce keystrokes• Keep the wrist in a neutral (straight) posture.• Hold the phone in a position that allows for a more upright neck

and upper back posture.• Keep moving, change your position often and take frequent

stretch breaks.• Do more on your computer. • Texting with two thumbs, with the back and forearms

supported, were less likely to be “symptomatic” than those who texted with one thumb, or sat with the neck and back bent forward.

Sizing up your smart phone

Smaller than 4.5 inches Medium 4.5-5.5 inches Larger than 5.5

Summary• Tablets are portable devices. The risk of rsi (repetitive stress injury)

with extended use is very real and clinics around the world are already diagnosing and treating such cases.

• Practically speaking-It is very difficult to adapt an ergonomically correct position, whenever someone uses and tablet or a mobile phone.

• There will however be certain scenarios when a correct ergonomical position or a near correct ergonomical position can be achieved.

• Users must therefore be trained in correct ergonomic use of such devices to enable then to correctly use them whenever possible.

• In situation which do demand certain deviations from the ‘ergonomic positions’ users should be educated in concepts of ‘rest breaks’, ‘stretches’ etc.

• Surely, ergonomists somewhere must be toiling away to ensure that the next generation of smartphones is likely to address these issues, and we are anxious to see how the user will view the screen with the head balanced over the shoulders, and enter text with the hands and wrists in a neutral position.

• Already, some devices provide options to allow a variety of postures to be used to control the devices (i.e. keyboard AND touch screen)

• In the next smartphones… how will the interface with the hand become more “neutral”?

• How will the devices project a display into a space where it can be seen with neutral neck and shoulders?

• Maybe people will learn a new syntax to reduce how much they have to type?• Will language recognition progress to allow us to enter sentences without

typing out full words? Is a stylus better than a keyboard??

The Future

References• REFERENCES• • http://en.wikipedia.org/wiki/Mobile_phone• An Ergonomic evaluation of the potential impact of touch screen tablets on office

workers. Katarzyna Marta Stawarz .Faculty of Brain Sciences, University College London,2012

• http://www.hsph.harvard.edu/news/features/ipad-ergonomics-dennerlein/• http://mentalfloss.com/article/29871/text-neck-hogwarts-headache-6-injuries-

modern-erahttp://graphicsweb.wsj.com/documents/smartphone-ergonomics/• An ergonomics study of thumb movements on smartphone touch screen Jinghong

Xiong, Satoshi Muraki Ergonomics Vol. 57, Iss. 6, 2014• http://m.ehstoday.com/health/text-neck-link-between-texting-and-

musculoskeletal-injuries• http://graphicsweb.wsj.com/documents/smartphone-ergonomics• http://www.taylordergo.com/texting-thumbs-shoulders-neck/

THANK YOU

Dr.Amol Sangekar-INDIAergowww.indiaergo.com