Tough people may not be the most talented or the most skilled, but they are persistent and present an indomitable spirit at all times. Toughness is a desired trait in a soldier, so, over the centuries, the military has perfected the process of making soldiers tough.
The martial part of the martial arts
The martial arts were created as a way to help soldiers kill the enemy in war, so they use many military customs and techniques. General Choi, the disputed founder of Taekwondo, was in the military when he developed his Taekwondo techniques and he taught the techniques to Korean soldiers as a part of their warfare training.
For centuries, soldiers have marched. Nowadays, even with modern combat vehicles, when you need to move large numbers of soldiers over ground, marching is an effective means. However, marching is has more utility than just for moving troops.