Muscle Training - Isotonic, Isometric, Isokinetic

All muscle training falls into either:

1. Isotonic training
2. Isometric training
3. Isokinetic training

Isotonic training

Here the muscle contracts and shortens to give movement. Nearly all training you will do will be isotonic.

Advantages of isotonic

• You can tailor isotonic training to suit your particular sport
• Strengthens a muscle throughout its whole range of movement

Disadvantages of isotonic

• The gains aren't spread out as the muscle strengthens at its weakest point of action not throughout.
• It can lead to soreness due to the stress while lengthening

Isometric

Here the muscle contracts but doesn't shorten so there is no movement.

Advantages of isometric

• You can pretty much perform these anywhere
• They need no expensive equipment
• They are quick and generally don't hurt
• These develop static strength which you need to push and pull heavy objects

Disadvantages of isometric

• During exercise, the blood flow to the muscle stops and blood pressure rises as less blood flows back to the heart - this is dangerous.
• The muscle gains are purely at the angle you use in the movement

Isokinetic training

Here the muscle contracts and shortens at constant speeds. An isotonic contraction is different to isokinetic contractions because it is slowest at the start. This type of training needs special equipment to detect when a muscle is speeding up so it increases the load, slowing it down.

Advantages of isokinetic

• The gains are spread evenly over the whole range of movement
• It is the fastest way to increase muscle strength

Disadvantage of isokinetic

• The equipment can be very expensive thus not available to all
• The difference between concentric and eccentric contractions

Concentric contractions occur when a muscle shortens in length to develop tension. Eccentric contractions include the development of tension while a muscle is being lengthened.

Concentric contractions have been shown to activate more muscle fibres in general however in the eccentric phase more fast twitch fibres are recruited not slow twitch. These findings are very useful to power athletes who want to train fast twitch fibres more so they would be more favourable to eccentric moves.

One way of training this eccentric way would be using plyometrics. These exercises like high powered jumps and hops would then train fast twitch fibres specifically.

Interestingly, DOMS - delayed onset muscle soreness - which occurs 24-48 hours after exercises usually results from eccentric not concentric contractions. This is due to the intracellular pressure irritating nerve endings and causing swelling and pain. However, an appropriate warm up and cool down will alleviate DOMS.

Article by:

Gemma Carter who is a fully trained fitness and life coach. Visit her website at http://www.cartercoaching.co.uk or email her at: gemma@cartercoaching.co.uk