A: Because your technique in weight lifting often creates the definition or size of your muscles, you may still see an increase in size even when lifting less weight. For example, your routine may require sixteen repetitions with light weights but some muscles may be exhausted after twelve repetitions. Those last four repetitions may cause an increase in muscle size.

Also, genetics plays a large role in muscle size. In the end, understanding how your body is designed may help you become more comfortable with how you look.