Micro-BULKING and Micro-CUTTING. Making gains without the added fat.
The typical bodybuilder or weightlifter exercises for cosmetic purposes. The only way to increase muscle size is by having an overload stimulus on the muscle (lifting weights) and by eating in a calorie surplus. A calorie surplus is when the person is eating more calories than they are burning. This leads to increases muscle growth due to the fact that there is excess nutrients and calories in the body that can be converted to new tissue. The problem with this is that after a couple months, the muscle gains start to slow and body fat starts to increase. This is the thing people are constantly concerned about. The ability to make gains while still staying lean. It is a VERY tricky thing to master, but there is a way to help the process.
The possible answer is micro-cutting and micro-bulking. On a traditional bulk, the person enters into a calorie surplus for typically 4-9 months. The added muscle gain is noticeable, but the added fat is usually trouble for many to get rid of. The person typically will enter into a cut phase after the bulk and restrict calories (calorie deficit) (eating less than the body is burning) to lose fat. By the time they are done cutting, the person typically loses a couple LBS of the lean body mass (new muscle) that they worked so hard for during the bulk. The process in then rinsed and repeated and it is hard to get good results.
With micro-bulking or micro-cutting, the length of time is not so extreme. The person may enter into a bulk (calorie surplus) for around 1-3 weeks, followed by a cut phase (calorie deficit) for another 1-3 weeks. This is a much better method because the added fat is kept to a minimum. Keep in mind, this is not the most efficient way to put on as much muscle as possible. However, if your goal is to stay lean and minimize fat year round, this strategy can be your best friend.
Workouts should never change. The major factor that determines body composition is the calorie intake.