Good Function

The Deep stabilising muscles of the trunk form a muscular cylinder surrounding the lumbar spine and pelvis. The deep stabilisers help control the position and movement of the trunk. The mover muscles are more superficial, they are the muscles you use to move your body.

The Deep Stabiliser muscles:

• Work at low intensity for long periods of time
• Generate tension to support and stabilise rather than move the body
• Contract before you move to support the body’s position
• Turn on in a similar way no matter what way you are moving
• Keep the spine and pelvis optimally aligned to maintain a neutral spine or ‘good posture’ position

The Mover muscles:

• Work at high intensity for short periods of time
• Generate force to move the body and change its position
• Contract at the time of movement to cause the movement
• Move the trunk and limbs
• Work differently depending on what movement you are doing

The deep stabiliser muscles only work at about 5% of their maximal contraction, but stay on for long periods of time. As they contract, the stabilisers don’t move your body much, if at all. They tend to apply tension and support structures rather than move your body.

When you think of moving, the deep stabilisers contract before any of the muscles that actually cause the movement. This pre-contraction prepares your body for the movement by supporting and stabilising the trunk to provide a stable base for movement.

A stable base makes for mechanically efficient movement or static postures. Imagine a crane being positioned on a solid concrete slab versus a sandy beach. The crane on the concrete slab is much more easily controlled by the driver who can be more accurate as the crane picks up and sets down objects. The crane on the beach will be much less accurate and take more effort getting the objects placed exactly where it wants them. The deep stabilising muscles of the body provide the stable base for the mover muscles to move the trunk and limbs.

The mover muscles are the ones which move your body. The mover muscles generate a lot of force and fatigue quickly. They turn on and off rather than staying on like the stabiliser muscles. You can easily work your mover muscles by moving your body against resistance such as the quads, hamstrings or biceps. In the trunk the mover muscles include the rectus abdominis (the six pack) and the obliques. These are the muscles you work with exercises such as sit ups or crunches.

Poor Function

The Deep Stabiliser muscles:

• Begin to turn off and on rather than staying on
• Contract after you move and so can’t support the body’s position as effectively
• Are less able to keep the spine and pelvis optimally aligned to maintain a neutral spine or ‘good posture’ position

The Mover muscles:

• Work at high intensity for longer periods of time to compensate for poor deep stabiliser muscles

The deep stabilisers change the way they work when pain is present. They no longer contract before you move to prepare or stabilise the trunk, they react to the movement. This can lead to injury. The movement muscles try and compensate. As mover muscles, they contract strongly and start to move the body, other muscles then pull on to counteract this movement. The body is working much harder to stabilise and using much more muscle activity than it needs to. This results in tight areas of the body which feel great when massaged out, but the tightness returns again. If your back pain behaves this way chances are you have trouble controlling your deep stabilisers and the pain arises from the compensatory strategies of the mover muscles.

Screening

A number of screening tests can indicate poor control of the core. There are a couple of quick tests you can do at home. If any of these tests give you pain, do not continue any further testing and see an appropriate health professional.

The active straight leg raise

Lie on your back and lift one heel about 10cm off the ground with your knee straight. Compare how difficult this feels compared with the other side. If one side is harder than the other, or both sides are difficult, you could have some issues with control of your core.

Source High Performance Golf