This is a highly common question I receive from people who are new to resistance training. The repetition range is one of the most important parameters in creating a successful training programme, but most beginners end up trying to copy what they see highly advanced athletes doing, leading to poor training results.
Before I delve into why this is a mistake, a little bit of detail on why exactly we might care about how many reps we are performing.
Why do the number of reps matter?
The rep range you are performing an exercise in is a reflection of how heavy the weight is. Interestingly, training with different percentages of your maximum strength results in your body making different training adaptations.
For example, when we lift a heavy weight that only allow us to perform 1 - 6 reps, the adaptation we get is primarily an increase in muscular strength. On the flip-side, if we utilise a weight that is relatively light such that we can perform 20 reps or more, the adaptation is primarily an increase in our muscular endurance.
In a race, marathoners (left) perform thousands of sub-maximal reps. The sprinter (right) performs far fewer reps and with much higher force. This is one potential factor in the large difference between the two athlete's body shapes.
For people training for muscle size, a medium weight that allows reps of approximately 6 - 12 appears to particularly useful, as the weight is heavy enough to allow large mechanical tension, but light enough to perform a high volume of work.
Bear in mind that these rep ranges assume that each set is performed with a proximity of at least 3 - 4 reps away from failure. Lifting a light weight for 6 reps doesn’t mean it’s strength training!
So low reps for strength and higher reps for muscle gain?
Nope, it’s not quite that simple. If you are unaware of how many reps you should be doing, chances are that you’re a novice in training. This means that you should not be putting yourself anywhere near heavy weights just yet. The reason why is because beginners do not possess the technical competency to lift heavy weights. If you try this, form will break down and injury may occur.
For beginners, the focus needs to be on using a resistance that is light enough to allow you to practice good technique, while also using enough weight to stimulate strength and muscle gain response. From personal experience I’ve found that sets of 15 - 20 are most suitable for this. Once your technique begins to become consistent, the reps can be lowered.
Remember that if you are just starting off in training, you must not rush the learning stage. The reality is that if you take the time to learn efficient technique on key exercises, you will get much better results down the line. Good technique is considered good because it allows you to lift larger loads. So don’t shortcut the learning process if you want to get strong and fit.
Lastly, nothing can replace spending some time with a good coach who can teach you how to move your body in a safe and effective manner. I will be running free workshops in the future for those who wish to learn the basic movements, so keep an eye out.