Strengthening Handbook

Overload principle

Neuromuscular adaptation occurs when the exercise volume exceeds its typical demands - without this strengthening does not occur

Work to fatigue

Reversible decline in the output of muscle due to an accumulation of metabolic by-products - marker that overload has occurred
Signs include; shaking, tremor, loss of quality and control of movement and inability to work the muscle through full range

Specificity

Improvements in muscle performance will correspond with the training regime
Type of training, the range trained, type of muscle contraction and speed and tempo of regime should replicate how the muscle needs to be used functionally

Progression and diminishing returns

Strengthening regimes need to be progressed regularly
As the muscle adapts to meet the demands of an exercise programme, the same regime becomes less challenging over time and therefore strength gains will reduce - law of diminishing returns

Reversibility

If a strengthening programme is not maintained, any gains in muscle strength will be lost

Exercise prescription

Should consider the frequency, intensity,, type and time of the exercise
Correct intensity is most important and difficult to achieve
Should work around patients 10-12 rep max

FITT - average for patient population

F = 3x weekly for MRC grades 4-5, daily for grades below 4
I = 60-80% 1RM or 10 rep max (70% of 1RM)
Ty = consider if muscle function is power or endurance - start with power then build endurance if very weak (include specificity principles)
Ti = 3 sets of 8-12 repetitions with one minute of rest between sets to reduce cumulative fatigue
From ACSM guidelines

Ways to make exercise more difficult

Stops and starts - Newton’s first law - increase muscle work required to re-start movement
Reduce momentum (slow or vary speed) - Newton’s 2nd law - by slowing or varying speed, greater muscle force required to elicit a change
Resisted movement - increases muscle force required to move the limb
Increase friction - Newton’s 3rd law - increases muscle work required to start or sustain the movement

Efficacy and progression

To progress;
Use different types of muscle contraction, strengthen the whole muscle range, lengthen the lever, add functional exercises, vary speed, increase resistance

Therapeutic principles

Use of targets
Motivation and correction if required
Competition with self or others
Variety of exercises and individual approach - consider patient age and interests
Instruction and demonstration
Explanation of potential benefits

MRC grade 0

No contraction of muscle - despite patient cooperating, no visible or palpable muscle contraction

MRC grade 1

Flicker of contraction - some contraction seen but patient unable to move through full range, even with gravity counterbalanced

MRC grade 2

Can move through full available range with gravity counterbalanced - PROM should be equal to ARIM with gravity counterbalanced

MRC grade 3

Can move through the full available range against gravity and with hold - PROM should be equal to AROM against gravity

MRC grade 4

Can move through full available range against minimal resistance - using measured resistance, can quantify this more reliably

MRC grade 5

Can move through full available range against maximal resistance - heavy or therapist or patient bodyweight - can be defined as normal function