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Are You Using Your Muscles Or Momentum When You Work Out?

What is momentum?

Newton’s Law of Acceleration explains the concept of momentum:

The acceleration of an object is directly proportional to the strength of the force, in the same direction as the net force, and inversely proportional to the mass of the object.

In layman’s terms, momentum gains strength with each repetition. Using momentum to get the weight moving means the muscles do not need to be fully activated to continue moving the weight through the full range of motion of the exercise. It’s basically cheating. By allowing momentum to take over you are no longer in control of the weight, which also places stress on the joints and spine.

How to recognise momentum during exercise

Have you ever seen someone do the following?

  • Pumping quickly through a set of exercises?
  • Swaying their back as they lift the weight for a bicep curl?
  • Swinging their arms through a movement?

If their movements were fast, resembled a swinging motion, and did not have a distinct beginning, middle and end, then they were using momentum. And while they might have finished their reps faster than the person next to them, their workout wasn’t as effective… so they were only cheating themselves.

Learning how to recognise and prevent momentum will ensure you exercise safely and efficiently, helping you reach your fitness goals faster.

Tips for preventing momentum:

Proper alignment - Make sure your spine and joints are positioned correctly before you start each exercise.

Distinct movements - Make sure your movements have a start, middle and end. If you feel you are swinging or bouncing stop and start the move again.

Stop at peak contraction - Stop at the mid-point of your repetition (eg. the lowest point of a lunge) to force yourself to recruit muscles to complete the move.

Slow, controlled movements - Moving slowly keeps constant tension on the muscles, removing momentum and recruiting more muscle fibres. The muscle fibres that are activated by slow movement are called “slow twitch”, and they are the fat burning muscle fibres which give that lean, sculpted look most women are after.

Take the time to think about what you are doing, and which muscles are working, and you’ll make the most of every single second you spend working out.