Intensity and effort are not the same in the strength and conditioning world. People usually assume that intensity is the amount of effort put into a workout or an exercise. Or they assume intensity is how hard the workout is to complete. Nope, not in the strength training field at least.
Here's a quick breakdown of what each word means when talking about resistance training:
Intensity refers to the weight used relative to your 1RM (1 rep max) in a given exercise. For example: Your 1RM squat is 275 pounds. If the program calls for 80% intensity, it means you're doing 80% of 275 pounds. That's 220 pounds. Simple. If it called for 100% intensity you'd be using your 1RM weight of 275.
Effort is how hard any physical work feels, which is independent of load. Consider these two scenarios:
- Scenario 1: Heavy squats for sets of 3 reps at your 3RM. This will feel like a massive amount of effort, like you have to lift this weight to save your life and not get crushed under the bar.
- Scenario 2: Much lighter squats for sets of 15 reps at roughly your 15RM. This will ALSO feel like a massive amount of effort. If you've ever done a set of squats for a 15RM you'll recall lots of shaking, panting, and "just a couple more, come on, you got this" thoughts in your head.
The point being, both will feel like a lot of effort because you're going to expend a lot of energy to complete the set in either case. The difference is that the sets of 3 are high intensity (about 90% of 1RM), while the sets of 15 are lower intensity by comparison (closer to 60% 1RM).
Effort can also be quantified by using the RPE scale. This is used to determine how hard a set felt or how much effort you had to put into it.
There are a few versions of the scale but the easiest is the scale of 1-10. One being the least amount of effort and ten feeling like you're fighting for your life throughout the set.
Let's use the light weight squats at 60% 1RM as an example. If you do them to absolute failure your RPE should be at a 9/10 or 10/10.
Let's say that rep count was 15 reps to failure. If you perform 5 reps at 60% 1RM you're clearly not putting in as much effort as the set to failure, but the intensity is the same because you're using the same weight (60% of 1RM).
There are more simple scales like "easy, medium, and hard." Depending on your goal it might only be important to note when you've taken a set to failure. You've clearly hit a max effort then.