Posted by Nicholas DiNubile, M.D. I am often asked what I believe to be the “best” number of sets and/or reps for a given exercise-both strength training and/or stretching. The correct answer is that there is no ideal formula that works for everyone. My recommendations will often vary depending on your fitness goals, past or present injuries, and your individual “weak-links.” Different individuals respond differently. Even in the same individual, different muscle groups may even respond differently.
In terms of strength training, intensity matters most. For the far majority of us, one set (10-12 reps for upper extremity and 12-15 reps for lower extremity) done properly, to exhaustion (i.e. “momentary muscular failure” or the inability to do another rep without sacrificing form) will give you the same benefit as multiple sets. Two sets become more important if you have problem areas, or old injured areas that need a lighter first set warm-up, something I always encourage if time permits. Other exceptions in which multiple sets for one muscle group would be recommended include serious bodybuilders, who usually use multiple exercises and sets for almost every body part, and also if you are rehabilitating a weak or injured body part in which multiple sets, done daily or even several times per day, are usually utilized. When injured or weak, it is often impossible to give maximum effort to the point where one set would be enough of a stimulus for gains. This is why, for example, we might have someone who has just had knee surgery do their thigh quad exercises even 4 or 5 times per day! Not a good idea for normal weight training in which I recommend a hard workout, followed by several days of rest for that particular body part — so that gains can be made.
Stretching can be safely done every day, and most of us don’t do enough. Two to three reps (slow controlled static stretch holding 10-20 seconds) are usually adequate, unless you have problem areas from old injuries or certain tight muscle groups that need more attention. Most adults have four areas that are almost always a little (or a lot) too tight: front of the shoulder; lower back; hamstrings; and calves.
The bottom line is that you should experiment to see what works best for you, but remember, it is more about the mindfulness and quality of the work you do, than the quantity.
What works best for you? Do you change numbers of sets and/or reps to avoid staleness in your workouts?