Also making sure the calf muscle can take any load and endurance of the activity with full mobility and tonicity of the muscle group when required will both help treat but also stop insertional Achilles Tendonitis from occurring. (sportsinjuryclinic.net)
We as modern humans have the tendency to sit a lot, which inevitably leads to a decline of tonicity in the muscles that give you an upright posture (mostly upper back musculature) and stiffens the muscles that give you a hunched - over posture (most promintently the pectorals / chest). (neatstrength.com)
More tonicity (meaning, more baseline tension from greater muscle mass) in the upper back pulls your shoulders back and makes your chest look broader. (neatstrength.com)