Sprint Vs. Endurance Muscles
I explain this to almost every new patient I see as it is a really easy concept to get your head around to help you understand a little bit more about your body and why good posture is important.
These are the big bulky strong muscles that are often referred to as the mirror muscles and that we like working on in the gym. These are the powerhouses of the body, they use plenty of energy, and are responsible for big body movements. Some examples are the Trapezius, Gluteals, Biceps, Quadriceps.
These are the fine delicate muscles, which are not very powerful but they have incredible endurance capacity and use minimal energy. These provide the joints and bones with low grade muscular support during static behaviours like sitting or standing. Some examples are your Core and Rotator Cuff muscles.
But Why Is Posture Important?
When you are sitting or standing correctly, all your joints should be perfectly stacked and the body weight travels straight down through the centre of each joint. In this position your endurance muscles are active, providing the joints with a little extra support to aid the upright posture.
What happens when we shift from ‘good’ to ‘poor’ posture is that our centre of gravity changes. The further our body parts shift from centre the heavier they become.
When we slouch for instance, all of a sudden your body weight moves forward and the load through the joints also shifts forward creating instability. Suddenly the Endurance Muscles are not strong enough to support this movement and so they tap out, and recruit your Sprint Muscles to help. This is great as it stops your from collapsing into a heap on the floor, however it is bad as these muscles are sprinters so only should be used from short periods of time. Unfortunately, with ongoing poor posture, you end up recruiting your sprint muscles for an ultra-marathon and they get fatigued, tight and sore.
If you suffer from pain that builds over the course of the day it is more than likely that you are sitting/standing poorly, recruiting your Sprint Muscles, which are fatiguing. Maintaining good posture is so important as it’s the most efficient way your body can work.