FALSE!!! You don’t have to be sore to get results. In fact, constantly increasing the volume of your training to continually make yourself sore can lead to overtraining, injury and a reduction of performance.
In two studies comparing the rate of perceived exertion and load, lower weights and higher reps were perceived as easier than a training that involved the use of heavier weights with lower rep range. Lighter loads are effective for creating gains in strength and muscle mass in beginners. Why not start your training with lighter loads and higher reps and slowly increase your weight as you become accustomed to resistance training?*
A slow progression also ensures consistency. If you constantly train so hard that you are in pain for a couple days, you miss workout sessions and lose motivation over time. A good exercise program is supposed to make your body strong and functional for everyday life …because if you move better you feel better.
* from “Fitness or Fiction” by Brent Brookbush