Let's kick off this blog with a quick anatomy lesson.
When you lift weights, you essentially damage your muscle fibres. After a workout, your body repairs and replaces damaged fibres to fuse them back together to form new muscle protein strands (myofibrils). This increases the thickness and number of myofibrils to create muscle growth.
Muscle is a metabolically active tissue, which means it requires calories even when at rest. People often refer to this as "Basal Metabolic Rate (BMR)" or "Resting Metabolic Rate", but it all means the same thing, it's the amount of energy your body needs to run itself.
Your BMR is primarily determined by your total lean muscle mass; the more muscle you gain, the more passive calories you burn.
Lifting a heavy weight between 70–95% of your 1-rep max activates your fast-twitch (type 2) muscle fibres and promotes strength development and muscle hypertrophy (growth). Is it the only way to gain muscle and burn calories? No. Is it the way I train and what I recommend to people that ask me? Yes.
Most people lift too light
But the truth is that most people following a hypertrophy training program don't lift heavy enough. At best, they aren't aware that they aren't putting in enough effort, at worst, they aren't trying at all (we've all seen people on their phones while on the leg press).
I know most of you are reading this thinking that you already push hard enough at the gym, but do you really?
While I cannot equip you with the mental and physical discipline required to consistently lift heavy at the gym, I can make you aware of a tool that I use to help assess how much effort I put into each lift and that's the Borg Rating of Perceived Exertion (RPE).
The Borg Rating of Perceived Exertion (RPE)
RPE is a way of measuring the intensity (effort) of your physical activity; perceived exertion is how hard you feel like your body is working.
The rating system goes from 1 (hardly any effort) to 10 (almost impossible). In practice, this could be the difference between lifting barely a weight at all (1) and lifting a weight that you can barely move (10), or walking at a snail's pace (1) and sprinting as fast as you possibly can for a short period (10).
Here's a graphic I created to show the different levels of exertion:
Without a target RPE for each lift, you will not be able to objectively assess your effort across consecutive weeks. I know from my own experiences when working out with others that they rarely put in enough effort until I explain what RPE is and hold them accountable for the duration of a full workout.
RPE in practice
If you plan to lift heavy, I recommend primarily training between RPE7 and RPE9.5. Remember that RPE is relative and the effort or "how hard you feel like your body is working" will differ from one week to the next or between sets.
For example, I program 3 sets of 10 reps on the barbell bench press at RPE8. After 2–3 warm-up sets, I add 60kg to the bar for my first set and complete it with enough energy to do 2 more reps (that's a perfect RPE8). However, I feel that if I had to do that for 2 more sets, it would require too much exertion and would push me into an RPE9 lift. So, I reduce the weight on the bar to 55kg for my second and third sets which allows me to maintain an RPE8.
After some time on a hypertrophy (growth) training program (and taking care of your nutrition), you will see your strength increase and muscles grow — and let's not forget that passive calorie burn. This is primarily because you are maintaining a high effort in your workouts.
How RPE feels and looks
Here is a way you can self-assess accurate RPEs:
RPE 7 - you felt like the weight moved quickly (like a heavy warm-up)
RPE 7.5 - you felt like you could maybe do 3 more reps
RPE 8 - you felt like you could do 2 more reps
RPE 8.5 - you felt like you could maybe do 2 more reps
RPE 9 - you felt like you could do 1 more rep
RPE 9.5 - you felt like you could maybe do 1 more rep
RPE 10 - you felt like you couldn't do any more
If, like me, you're a visual learner, then seeing what RPEs look like will be the best way for you to learn. Here are examples from my gym sessions (excuse my "gym faces") for RPE9.5 and RPE10.
RPE10 (the last 2 reps were intentional cheat curls)
A free 6-week training program
If you are looking for a hypertrophy training program that doesn't include too-technical lifts and includes low-intensity steady-state cardio (LISS) — my recommended form of cardio — I've created a free 6-week training program. This program is a push/pull/leg split, which includes target RPEs for all exercises and some helpful tips.
Before starting any program, I recommend that you:
Search YouTube for any exercises you don't know to ensure the correct form.
Do a "primer" week before you start if you're a beginner. This is a week where you follow the program but lift light weights to ensure you know what you're doing and to help avoid injury.
Ascertain your RPE weight for each exercise, which can be done by "feel" (see above) or by using a free online tool, such as Lift Vault's RPE Calculator.
If you are anxious about starting a heavy lifting program, I suggest you seek guidance from a reputable personal trainer.
If you'd like to keep up to date on the workouts I do and the meals I receive, you can follow me on Instagram.