Physical Ability

It will be not funny if you master many technique of martial arts but you will get knockout with one punch landed on your body or face. Also it will be weird if you have strong kicking strike but you only can fight in about 1 minute.

Stamina and physical ability play important role in martial art, whether in a match or real life fighting. More stamina means you can fight in long lasting time, and good physical ability made you as strong as rock. I have seen fighter with overweight body ( 155 kg with height 200 cm), yes in a match its ok, but not in real life. 155 kg means his weights are 3/4 his height, its obesity. Although he has good muscle, but automatically his movement will be slower and will absorb to many energy.

To train stamina and physic are easier than trains technique. But you need more commitment in training, because it will be hard and makes you tired. Running, sit up, push up with great amount of quantity will get you to better stamina and physic. That are the cheapest way, you dont need to pay for gym or fitness centre.