As a triathlete and runner we want the mid section to be stable as possible in order to allow the legs and arms move freely.
Here is four reasons why you should strengthen your core.
To run taller - envisage your core as a corset - like structure that wraps around your torso holding your body erect. If your body’s core is weak your spine will collapse and curve, creating rounded shoulders and poor overall posture.
To run faster (and tackle hills) - gluteus maximus is often omitted from core training sessions, but this thick buttock muscle helps drive your body forwards. Sprinters rely on glute max more than endurance runners, but a good level of strength in your buttocks - and the entire core - will benefit all runners by allowing the legs to generate more force and speed. The extra power supplied by a strong glute max is especially useful in short sprints or when tackling hills and adds to overall resilience.
To limit unnecessary rotation - a key function of the core , especially the internal and external obliques at the side of your waist, is to minimise upper body rotation in running. This means that your body is moving in an efficient forwards - only motion or sagittal plane rather than swaying from side to side. Restraining this movement creates a more economic stride and saves precious energy for the run.
To prevent injury - a weak core can cause numerous problems in runners, and triathlon, from irrtating your pelvic muscles to stressing your knee joints or causing nagginig lower backache. This is especially the case for runners with sedentary desk jobs who may already have muscular weaknesses in the abdominals and glutes. Of course a strong core is only part of the story with injury prevention, a whole body strengthening and stretching routine is the ideal preventative solution.