Hi all,I've got my first half marathon in March and have been wondering if it's possible to change your style,front foot or heal strike,when running tired it seems i plant my heal alot but then later have heavy legs/sore hips.Is this just because I'm not that good a runner or can you train to have a better more efficent style.Hoping to continue running this year,got fed up swimming with arms and legs in my face in Tri's.