Students can spend long hours sitting while reading, studying or working on assignments, often in awkward positions. Poor posture can happen easily, particularly as we get caught up concentrating on the task at hand.
Sitting in less than optimal positions for prolonged periods of time can interfere with many of the body’s normal postural mechanisms, including “slow twitch” and “fast twitch” muscle fibres, muscle strength and length, and nervous system feedback on the body’s position in space. Poor posture can cause muscles and other soft tissues to become abnormally stretched or shortened. This can lead to pain presenting as headaches, neck and low back pain, or pain in the shoulders, elbows, wrists and hands, as well as eye-strain, general fatigue and repetitive strain injuries, such as tendinopathies or carpal tunnel.
Before we talk more about poor posture and what to do about it, let’s learn a little more about the body’s normal postural mechanisms…
Muscle Fibre Types
Skeletal muscle is made up of two different types of muscle fibres – static (often called “slow twitch”) and phasic (often called “fast twitch”). Static muscle fibres are most often found in deeper muscle layers and help to maintain posture. Phasic muscle fibres are used for movement and activity. Static muscle fibres burn energy slowly and can therefore work for long periods of time without becoming fatigued. In contrast, phasic muscle fibres tire quickly. Good posture allows these muscles to work in the way they were designed and therefore feels effortless. Poor posture, however, forces phasic muscles to work to maintain the body’s position instead of the static muscle fibres, causing muscle fatigue.
Muscle Strength and Length
Muscles are designed to function in an optimal position in which they do not require excessive amounts of energy to perform a contraction. As mentioned above, muscles are also created with different fibre types depending on their intended function. Over time, poor posture that requires phasic muscles to work and take over the role of the deeper supporting muscles results in the static muscle fibre types wasting away from lack of use. Weak, unused muscles tend to tighten up and eventually shorten, further worsening posture by compacting the bones of the spine. As posture changes, it then becomes a vicious cycle of poor posture, leading to muscle weakness, leading to muscle shortening, leading to worsening posture…you see where I’m going with this!
Nervous System Feedback
We spoke a little above about the muscle fibre types and how they work. Another role of the deeper (static) muscles is to provide information to the brain about the body’s position in space. If the wrong muscle type (in this case the phasic muscle fibres) are taking over the role, the brain receives inaccurate information and thinks that the supporting muscles are not doing their job. The brain then assumes that the body needs to be propped up and triggers further muscle contraction, resulting in increased muscle activity and increased fatigue in the body.
With many different systems all working together to support our posture, it’s no wonder that poor posture can have so many effects!
Now, back to those students!
If we were to look around a classroom or a library, we would see many people sitting in a slouched position, often in poorly designed seats and at awkward desk arrangements. Instead of the lower back maintaining its natural arch, it rounds out. The upper body and head then drop forward, causing the upper part of the neck to over extend so that the head can keep looking up. Instead of the bony structure of the spine bearing most of the weight, the upper body weight is transferred to the muscles, ligaments and intervertebral discs.
Sometimes, such as in the classroom, it can be difficult to have control over the type of furniture provided or the way a desk is set up, however we can work with what we’ve got, then set up a great study environment for home.
So…how do we support good posture?
The following tips will help to reduce stress on the body:
1. The desk
- should have enough desk top space so that the computer monitor can be approximately one arm’s length away
- should be at a height that allows the wrists to remain in a neutral position when using a computer and the shoulders to remain relaxed
2. The chair
- should be adjustable and comfortably padded
- should be adjusted so that your arms are slightly above the desk with shoulders relaxed and elbows bent to 90o, knees bent at right angles and in line with your hips with thighs parallel to the floor and feet flat on the ground (a foot rest may also be required to help maintain this position)
- should maintain the spine in a vertical or slightly reclined position
- should provide adequate low back support (to maintain the natural curve of the lumbar spine) – a lumbar roll or rolled up towel may be required to provide extra support
- sit all the way into the seat – push your hips as far back into the chair as possible as this allows you to use the back rest for support to sit straight giving your muscles a break
3. The monitor
- should be positioned directly in front of you so that your body and head are not rotated
- should be positioned so that the top is at or just below eye level – you should only need to move your eyes (and not your whole body) to see the screen
- you may need to prop your monitor on some books to ensure that it is correctly aligned – if it is too low, too high or not centred, you will find yourself tilting or turning your head to see the monitor, causing neck and shoulder pain
- should be approximately an arm’s length away from you – sitting too close or too far away can strain the eyes
4. Keyboard and mouse
- place your keyboard directly in front of your body – it should be positioned with the letter “b” in line with the middle of your stomach to avoid your wrists from deviating to one side too much
- you keyboard should be a comfortable reaching distance (elbows should be at a 90o angle and kept close to your body) – ensure you can rest your arms on the desk to minimise strain on your neck, shoulders and shoulder blade muscles
- the keyboard should be elevated to a height so that the wrists are in a neutral position
- try to avoid glare on the computer screen (this can cause eye discomfort and headaches) – close window blinds, change brightness and contrast settings on your computer or reposition internal sources of light such as lamps
- avoid having the computer up against a window or bright light – this can make the screen difficult to see and cause you to lean forward, straining the neck
- study in well-lit areas to avoid straining your eyes and to avoid bending to see the reading material
Now that your study area is set up appropriately, here are a few other tips to help prevent pain due to poor posture:
- a document holder just off to the side of the computer monitor may be helpful to prevent excessive rotation of the neck and body
- avoid sitting with your legs crossed or sitting on one leg for extended periods of time – this can lead to poor circulation as well as placing pressure on the hips and spine
- try to avoid resting your wrists on the sharp edge of the desk while typing
- take intermittent eye breaks to avoid eye fatigue – refocus your gaze from your computer screen to objects in the distance
- take regular study breaks (every 30-60 minutes) – spend a few minutes stretching or walking around to stimulate blood flow and to move the areas which have been in a shortened or lengthened position for a long period of time
- schedule in at least 30 minutes of physical activity per day to keep muscles healthy, strong and better able to endure stress
Unfortunately for our students, study is unavoidable. However, with these guidelines, we can hopefully make the study environment much more comfortable and avoid unnecessary stress on the body. Remember that if you require any further information, or if pain is persisting, seek the advice of your physiotherapist, GP or other health care provider.