Discipline, commitment, and hard work are all important pieces of hitting a goal but when was the last time you were relentless about achieving something? Being relentless may just be the factor that is missing from getting what we want.
Being relentless towards something, such as your health, means that we can't accept something getting in the way of what we want to achieve. There will always be obstacles and bumps in the road, but if you are relentless you will find a way around or through them to get to your goal.