How Much Weight Should I Lift?
Are you working hard enough? Maybe you’re working too hard? Here I will provide you with a simple framework to help you select the right weight for strengthening exercises. I will also discuss how to progress your strength – this doesn’t mean just adding more weight again and again.
Why is this important?
Intensity is an important factor in dictating the amount of strength/muscle building stimulus an exercise will provide. You can increase or decrease the intensity of most strength training exercises by increasing or decreasing the weight. The other key factor in strength/muscle building is called volume – the total number of repetitions and sets of the exercise you perform. A common volume used with physiotherapy exercises is 3 sets of 10 repetitions. This volume has been show by numerous research studies to be effective at building muscle size and strength. Obviously, this is not the only volume that is effective, but I will save discussion on that topic for another time!
Now if you select a weight that’s too heavy, you won’t be able to do enough volume to elicit change in your muscle. If the load is too light, there is not enough demand placed on the muscle to stimulate it.
Rating of Perceived Exertion
The rating of perceived exertion (RPE) is a tool we can use to decide if an exercise is too hard or too easy. For this to work, you’ll need to pay attention to how tired the muscle you are working is feeling (or how much it’s burning!). RPE can be measured on a 0 to 10 scale, with 0 being no effort at all and 10 being maximum effort (you could not perform another repetition in that moment). You will measure your RPE once you’ve completed the last repetition of the last set you performed. If you performed 3 sets of 10 repetitions, then you want to decide what your RPE was on the 10th repetition of that 3rd set.
What is an Appropriate RPE?
It is not necessary to always push to failure (10/10 effort) in order to stimulate muscle and strength growth. The training zone for the RPE you chose is dependent on a couple of factors:
- Are you recovering from and injury or surgery?
- Have you done strengthening exercises before?
If you’re recovering from an injury or surgery and/or have not done strengthening exercises before, it’s a good idea to start at a lower intensity. In these situations an RPE of 6-7/10 is appropriate.
If you are pain free and have no recent injuries and/or have been strength training for a while, then you can work at an increased intensity with a RPE of 8-9/10.
How to Progress Strength Exercises
As you work on a strengthening exercise, your muscle will gradually adapt to the workload you apply to it – it gets stronger! Continuing to work at the same volume and intensity will lead to a plateau in your strength gain. If you want that muscle to continue to grow stronger, then you’ll need to change either the volume or intensity. It is generally not a good idea to increase both variables at once. With my patients, I generally like to increase the volume (while keeping the intensity the same) first. Once that level is no longer challenging, I will have them decrease the volume, but increase the intensity. Here is the framework:
3 sets x 10 repetitions —> 3 Sets x 12 repetitions —> 3 sets x 15 repetitions
Example:
For this example we will use the biceps curl exercise. We will also use and RPE range of 6-7/10. First, you will need to pick a weight that elicits an RPE of 6-7/10 by the time you’ve finished the 10th repetition of the 3rd set. This will often require some trial and error over the course of a workout or two. Let’s say you’ve discovered that 10 lbs is what works. Great! You’ll want to continue with this volume and intensity for a week or two (or however long it takes for your muscle to adapt):
| Biceps Curl | Weight (lbs) | Sets | Repetitions | RPE |
| Week 1 | 10 | 3 | 10 | 7 |
| Week 2 | 10 | 3 | 10 | 6 |
| Week 3 | 10 | 3 | 10 | 5 |
You can see in this example, by week 3, the RPE has dropped below our training zone and you’ll need to change something. Rather than increasing the weight, you’ll increase the repetitions first. By doing more repetitions (12), you’ll produce more fatigue in the muscle, and push your RPE back into your training zone
| Biceps Curl | Weight (lbs) | Sets | Repetitions | RPE |
| Week 1 | 10 | 3 | 12 | 7 |
| Week 2 | 10 | 3 | 12 | 6 |
| Week 3 | 10 | 3 | 12 | 5 |
Again, as you work at the same intensity and volume, your body adapts and the exercise feels easier (decreasing RPE). When the RPE drops below your training zone, it’s time to increase the number of repetitions once more – this time up to 15.
| Biceps Curl | Weight (lbs) | Sets | Repetitions | RPE |
| Week 1 | 10 | 3 | 15 | 7 |
| Week 2 | 10 | 3 | 15 | 6 |
| Week 3 | 10 | 3 | 15 | 5 |
At this point you have maxed out the amount of repetitions in the framework I have provided, so now it’s time to decrease the volume back to 10 repetitions per set, but increase the intensity by a couple of pounds
| Biceps Curl | Weight (lbs) | Sets | Repetitions | RPE |
| Week 1 | 12 | 3 | 10 | 7 |
| Week 2 | 12 | 3 | 10 | 6 |
| Week 3 | 12 | 3 | 10 | 5 |
There you have it! You can apply this framework to any strengthening exercise, whether the purpose is to rehabilitate an injury or to build general strength. If your physiotherapist has given you several strength exercises, it’s important to note that you don’t have to progress all the exercises at the same rate. This means you can do more repetitions of an exercise that’s feeling easy but continue doing fewer repetitions of an exercise that is more difficult.