Three Ways to Measure Your Strength Training Intensity
When it comes to effective strength training, intensity is everything. Understanding how hard you’re working during each set can help you hit your goals faster, avoid injury, and make consistent progress. But with multiple ways to gauge intensity, it can be tricky to know which method is best for you.
In this blog, we’ll explore three common ways to measure your training intensity: RPE (Rate of Perceived Exertion), RIR (Reps in Reserve), and percentage-based training. Each method has its own strengths and ideal applications, so let’s dive into how they work and how you can incorporate them into your workouts.
1. RPE (Rate of Perceived Exertion)
What It Is: The Rate of Perceived Exertion (RPE) is a self-assessed measurement that rates the difficulty of an exercise on a scale from 1 to 10, with 1 being extremely light activity and 10 being maximum effort where you couldn’t perform another rep. The RPE scale was initially developed for endurance activities, but it’s now widely used in strength training to help lifters gauge intensity without relying solely on weight or rep counts.
How to Use It: In an RPE-based workout, you’ll assign a rating to each set based on how hard it feels. For example:
RPE 1-3: Very light. Could continue almost indefinitely.
RPE 4-6: Moderate effort. Could do several more reps.
RPE 7-8: Challenging, but not maximal. Could do 2-3 more reps.
RPE 9: Near max effort. Could do 1 more rep.
RPE 10: Maximum effort. No additional reps possible.
An RPE rating can be given at the end of a set, or you can choose to target a specific RPE before starting. If you’re aiming for an RPE 8, you should finish your set feeling like you could still do 2-3 more reps.
Why It Works: The RPE scale is a flexible tool that adjusts to your energy levels on any given day. If you’re not at your strongest due to poor sleep, stress, or muscle fatigue, your RPE will reflect that, allowing you to lift at an appropriate level without overdoing it. This approach can help prevent burnout and injury while keeping you on track.
Best For: RPE is excellent for those with some experience in strength training who can accurately gauge their exertion level. It’s especially helpful in periods of high-stress or fatigue, as it allows you to adapt to your daily capacity.
Example in Practice: Say you’re performing bench presses and aiming for an RPE of 8. If you finish your set of 8 reps and feel like you could only do 2 more, you’re right where you should be. If you could do 4 or more reps, it’s time to increase the weight or reps to meet your RPE target.
2. RIR (Reps in Reserve)
What It Is: Reps in Reserve (RIR) is a measure of how many reps you have “left in the tank” at the end of a set before you’d reach failure. For example, if you finish a set and feel like you could perform two additional reps, you’re training at an RIR of 2. Like RPE, RIR is a self-assessment tool, but instead of rating the overall difficulty, you focus on how close you are to muscular failure.
How to Use It: Incorporating RIR into your workout involves ending each set with a specific number of reps left before failure. Here’s what common RIR values look like:
RIR 4+: Very low intensity. Plenty of reps left in reserve.
RIR 3: Moderate intensity. Could do 3 more reps.
RIR 2: Challenging. Could do 2 more reps.
RIR 1: Near maximal effort. Could do 1 more rep.
RIR 0: Maximum effort. No reps left in the tank.
Setting a target RIR helps you decide when to increase or decrease the weight for optimal progress. For example, if your goal is an RIR of 2 but you feel like you could do 5 more reps, it’s a sign that the weight is too light.
Why It Works: RIR allows you to regulate intensity with a clear focus on muscle failure. Tracking your reps in reserve provides a gauge for gradually increasing intensity as you get stronger. It’s particularly helpful for building muscle and strength safely, as it helps you avoid training to failure too often, which can lead to injury and burnout.
Best For: RIR is ideal for lifters focused on progressive overload and strength gains who want precise control over their training intensity. It’s also useful for avoiding overtraining, as it sets clear boundaries for how hard you’re pushing yourself.
Example in Practice: Imagine you’re doing squats with a goal of RIR 2. If you finish a set of 5 reps and feel like you could do 2 more, you’re on track. If you feel you could do more, it’s time to increase the weight or reps next time.
3. Percentage-Based Training
What It Is: Percentage-based training involves using a set percentage of your one-rep max (1RM) to determine how much weight to lift. Your 1RM is the maximum amount of weight you can lift for a single rep on a given exercise. In percentage-based training, you select weights based on a percentage of your 1RM to control the intensity for each set.
How to Use It: To implement this method, you’ll first need to know your 1RM for key lifts (or at least have an estimated 1RM). From there, your workout intensity can be set using percentages like these:
50-60% 1RM: Light intensity. Used for warm-ups or endurance-focused sets.
65-75% 1RM: Moderate intensity. Ideal for hypertrophy (muscle growth).
80-90% 1RM: High intensity. Effective for building strength.
90-100% 1RM: Near-maximal to maximal effort. Reserved for peak strength testing.
If your 1RM on the bench press is 200 pounds, lifting at 75% intensity means you’ll use 150 pounds for that workout.
Why It Works: Percentage-based training gives you a structured, quantitative approach to intensity that’s easy to track and adjust. It’s especially useful when following a specific program geared toward strength gains, as it allows you to monitor progress objectively. The progression over time (such as increasing from 70% to 80% of your 1RM) helps ensure that you’re challenging yourself at the right level for growth and strength adaptation.
Best For: Percentage-based training is great for advanced lifters who know their 1RM and want a structured approach. It’s commonly used by powerlifters, Olympic lifters, and athletes focused on strength gains. This method can be rigid, so it’s best for lifters who can regularly test or estimate their 1RM.
Example in Practice: If you have a 1RM of 300 pounds on the deadlift and you’re following a program that requires you to lift at 70% intensity, you’ll load the bar with 210 pounds for that session. If you then aim to increase your 1RM over time, you can see improvements clearly in your percentage-based weights.
Choosing the Right Method for You
Each of these three intensity-measurement methods has unique strengths, so the best one for you depends on your goals, experience level, and training style. Here are a few scenarios to help you decide:
For Flexible Intensity Management: RPE works well if you want to adjust your intensity based on how you feel each day, providing flexibility that adapts to fluctuations in energy and strength.
For Precision in Progressive Overload: RIR is a great option if you prefer a structured approach to avoid burnout while ensuring you’re working close to failure in a controlled way.
For Quantitative Tracking: Percentage-based training is ideal for those who want a numbers-driven approach to intensity, particularly if you’re training with specific strength goals in mind.
Remember, you can also combine these methods. Many lifters use RPE or RIR for accessory exercises while reserving percentage-based intensities for their primary lifts.
Final Thoughts
Understanding how to measure intensity is essential for getting the most out of your training. Whether you prefer the flexibility of RPE, the precision of RIR, or the structure of percentage-based training, each method offers unique benefits that can help you progress safely and effectively.
