Doing less only results in more if you are exceeding your ability to recover by doing more. I feel like people have gone overboard in recent years espousing extremely low volume routines. Here are the facts to keep in mind:
- You have a limited ability to recover. If you exceed this capacity, you will not optimize results. Major factors that influence one's ability to recover include genetics, hormones, sleep, nutrition, and other stressors.
- Working out doesn't build muscle, it breaks down muscle. The stress imposed by resistance training causes tissue damage. It is during your recovery from the workouts that you repair this damage and supercompensate, or re-build beyond the previous baseline.
- If you are not pushing the limits of your ability to recover, then you can, and should, do more. Less is only more if you are exceeding your ability to recover. In fact, over time it is a good idea to try and increase work capacity. Read some stuff from Louie Simmons on this topic.
- The more intense the activity, the more difficult it is to recover from. Therefore, you can get away with doing less if the activity is more intense. You can't half ass it in the gym at very low volumes. If you do plan on performing a low volume routine, you need to be busting your ass.