I often wonder how personal trainers, coaches, or people who run or work out on their own come up with the number of reps for their workouts. There’s no magic in doing 5 or 6 or 7 reps. And when training in a group, there’s little reason why everyone should do the same number of reps. The number of reps is arbitrary. Watch the video to see how you should decide on the number of reps you do.