Neural control

Question 1

In healthy adults, activation of the local muscles, or inner unit, occurs as a what, and why?

Answer 1

co-contraction some 30–110 milliseconds prior to outer unit muscles

due to a pre-programmed response, which ensures that these muscles are activated automatically and independently of other muscles to ensure stability of the spine.

Question 2

If the inner unit is not activated prior to the outer unit, the spine will not be what? resulting in what?

Answer 2

sufficiently stabilised

increased forces on the spine and its related structures, such as the discs.

Question 3

In back pain patients, this stabilisation mechanism often does not ___________

Answer 3

activate prior to the muscles of the outer unit.

Question 4

Sometimes the nervous system will activate muscles either side of the trunk to stiffen the spine. For example:

Answer 4

when performing a heavy squat or deadlift, your abdominal muscles will be co-activated with the back erectors to ensure stability.

Question 5

If the superficial mobilising muscles are overtrained, what can this cause? (2)

Answer 5

1. they may become over active inhibiting the stabilising muscles
2. they may shorten, causing them to become fibrous and unable to not stretch to their full length - this may cause inhibition of opposing muscle groups and changes in biomechanics and posture

Question 6

Give an example of a superficial muscle becoming overtrained, and what this may cause

Answer 6

if the muscles of the spine become short - the abs and glutes can not contract fully, meaning the hamstrings have to contract to compensate, resulting is inefficiency and risk of injury

Question 7

If an individual’s mobilisers are strong and their stabilisers are weak what can this cause?

Answer 7

the kinetic chain will sense imbalance and forces will not be transferred or used correctly

Question 8

Give an example of an individual with weak stabilisers and strong mobilisers.. what can this cause?

Answer 8

many people have strong abdominals and weak back extensors for example, this can result in unwanted spinal movement of the individual spinal segments, resulting in greater force through the spine and risk of injury

Question 9

Give an exercise example without sufficient stabilisation and what this can cause

Answer 9

performing the back extension without sufficient stabilisation can increase disk pressure and cause damage to the spinal segments