Q: What is eccentric contraction and why is it important to include in your training?
A: There are actually three types of muscle actions: isometric, isotonic and isokinetic. Most people in the fitness industry are familiar with isometric and isotonic actions.
An isometric action occurs when the muscle generates force but the length of the muscle doesn’t change, and there is no change in the joint angle.
During an isotonic action, the length of the muscle changes and can be further broken down into concentric and eccentric actions.
- A concentric action occurs when the muscle generates force to create a movement, causing it to shorten and decrease the joint angle
- An eccentric action occurs when the muscle generates force to control a movement causing it to lengthen and the joint angle to increase
Most people are very good at creating a concentric contraction, but have a more difficult time with eccentric phase. This phase requires a greater degree of muscular control. If we use the example of a bicep curl, it’s easy for people to connect the anterior arm muscles to flex the elbow, but they often lack control when returning to elbow extension.
Q: Why is it so important to maintain control in the eccentric phase of a movement?
A: Simply put, eccentric training is important to ensure greater all-around muscle strength, to enjoy prolonged activity and to avoid injury! Some great strengthening tools to use would be our Resistance Loop, Flex-Band Loops or Flex-Band. You can also work on eccentric control using spring tension found on some of our larger equipment.
The smaller fitness accessories are often used in Merrithew® Matwork programming as each one is flexible and offers the stretch and recoil function. This is key to providing feedback to the muscle, especially on the eccentric phase, to say, ‘Hey muscle, you need to still work to control the recoil back to the starting length’. Handweights or Toning Balls may not have the same effect except when paired with proper cueing, technique and control.
As an instructor, I am constantly making sure my clients are controlling their movements as this is often the phase where injuries occur. This is also the phase where optimal muscle strength is achieved and my clients are most challenged both mentally and physically. I’ve seen the biggest changes in a client’s strength and stability when focus is placed on both types of muscle actions.