Is it OK to work out one day and play sports the next day. Does it affect your muscle building progress or do you need to take complete rest the next day after a workout session?

The answer depends on the nature of your workouts and your sports. If your sport is intense on a particular muscle group, such as soccer, then you should rest that muscle group, such as your legs, the day before. If you work your arms, hips and chest heavily the day before the big Golf tournament, you probably won't hurt yourself, but your game might suffer.

Muscular strength, size, and definition are achieved by basically telling your muscles, through artificial example, that you need this size, strength, and definition to accomplish the tasks in your daily life. From the perspective of our muscles, their job is to make sure that we can move and lift what we need to (that's why if you don't use your muscles much, they can get smaller).

Muscles can be overworked by exhausting them, injuring them (that moderate sore feeling you get later), and pushing them beyond their limits. Once they get to that point, they need to rest. The more they've been pushed, the more badly they need the rest in order to heal and recover. Playing an athletic or intense sport the day after an intense workout might not be a good idea in many cases, but might be okay if different muscle groups are involved.