Can you learn to play the guitar without a guitar? Nevertheless, many of the conditioning exercises and mobility drills can be done solo. To learn to fight a human being though, you need to train with a real human being, and nothing can fully replace that.
That depends on how much thought, time, and effort you put into it. Ideally, you should be training at least two hours a week. Though training never ends, after three months of serious work, you will be a different person physically, psychologically, and emotionally.
I think that most of the fitness programs out there today are really great. The goals of our fitness program are a bit different than those of most other programs out there. People today are busy chasing good looks. All they are really concerned with is to have a good body. Having a good body, however, does not necessarily mean you have a healthy body that will stay with you many years down the road. If I have a six pack, and big biceps but walk around with 20 percent muscle tension, I may look good but my body is not healthy. All that tension drains my body from precious energy and makes me emotionally tense as well. From a combative perspective, subconscious tension will limit your freedom of movement, which can cost you dearly.

So in Direct Combatives, we try to learn from Russian Systema. Working on strengthening tendons (which protect your joints), while relaxing your muscles. A strong emphasis on proper posture and breathing helps make sure that you are not damaging yourself while working out. Our philosophy is to not idolize and worship the body. We understand that the body is our tool to do good deeds and to make the world a better place. To accomplish this to the best of my ability, I need to keep my body healthy.

About 75% of the exercises from the solo workouts in the Fitness program will be covered throughout the Martial arts class. They will be very spread out though, according to the topics they are relevant to. The other workouts will not be covered anywhere in the Self-defense program.