Musclechemistry Board Certified Member
Lower repetitions with heavier weights are good for gaining strength. While higher repetitions with lighter weights are good for muscle endurance. But when muscle growth is the goal, things tend to become more confusing. Swipe left on the post above for more details on muscle growth and rep ranges!
You may have heard that 8-12 repetitions per set is the best rep range for muscle growth. But if we look at the research, we see that a wide variety of rep ranges work for gaining muscle [1, 2]. For instance, 1 study compared lifting with 8-12 repetitions or 25-35 repetitions per set [3]. Both groups trained to muscle failure and it was found that muscle growth was similar. This is encouraging because it shows that even if you train at home with light weights, you can still gain muscle if you challenge yourself.
It's also worth mentioning efficiency. If you perform 20+ reps close to failure every set, your sets will take a long time and be fatiguing. Whereas if you train only with 5 or fewer reps per set, every set is demanding and places more stress on the joints. That's why I like using the general guideline of training within a 5-15 rep range. About 5-10 reps per set on compound movements and 10-15 reps per set on isolation lifts. You will have efficient working sets, but still can train in a variety of rep ranges.