It’s now important to understand how strength works. When our muscle contracts, we develop force. The ‘harder’ a muscle contracts, the larger the force output.
Muscles are made up of muscle fibres. Muscle fibres are controlled by motor nerves. Motor nerves will innervate a group of muscle fibres. This is known as a motor unit. We have low threshold motor units and high threshold motor units, which are activated with lower and higher intensities respectively.
Strength adaptations are largely achieved via activating our high threshold motor units. The most popular way to do this is to lift heavy loads. Here, we need to activate all of our motor units to overcome the external load. However, with calisthenics, there is a point where many exercises will feel relatively easy. But, there are still ways to recruit those high threshold motor units.
One way is via lifting speed. Back to our quick physics lesson, force = mass x acceleration. If we accelerate quicker, we increase our force production through activating our high threshold motor units. Explosive exercises therefore become a highly effective method for motor unit recruitment with bodyweight training.
Another way is lifting close to failure. You will see more exercises prescribe AMRAP (as many reps as possible). Here, as the low threshold motor units fatigue, we need to still somehow maintain our force production to overcome the external load. Using this method, we recruit our high threshold motor units as we approach failure.
Simon Ata (aka Simonster) is a world leader in bodyweight training. Starting gymnastics at an early age, he became passionate about mastering control of the body and immersed himself in the world of bodyweight strength training. Attaining a Bachelor of Physiotherapy degree alongside personal training qualifications, furthered his understanding of the body from an academic side and accelerated his training methods and skill.