Predict 1RM with this submaximal strength test (VBT)

We all want to know our one repetition maximum (1RM) to measure strength, set weightlifting goals and track progress. There is one problem though: performing a 1RM test comes with several problems and risks. In this article we share how to accurately predict 1RM, without performing a risky 1RM repetition. Instead of using basic 1RM calculators – that require injury prone max efforts – we show how to calculate 1RM, using velocity based training.

By Loek Vossen

Content menu:

• What does 1RM mean
• What is 1RM used for
• Traditional 1RM testing
• 1RM testing problems
• Submaximal 1RM test
• Standard 1RM calculators
• How to easily predict 1RM, using velocity based training
• Setup GymAware 1RM prediction

Before we dive into the solution, let’s first make sure we are on the same page.

What does 1RM mean

1RM stands for “1 Repetition Maximum”, which is the maximum weight that you can lift for one repetition of a specific exercise.

For instance, if you say your 1RM squat is 100kg, you mean that the maximum weight that you can lift one time, in a squat exercise, equals 100kg.

What is 1RM used for

In practice, athletic trainers, health and fitness professionals and rehabilitation specialists use 1RM as a measure of a person’s strength or strength imbalance. 1RM also helps to set weightlifting goals or to track progress.

You now know what the point is of knowing your 1 rep max. Let’s continue by looking at a traditional 1RM test.

Traditional 1RM testing

A 1RM test is very straightforward. After a warm up, you try to lift a heavy weight that you think is your maximum weight for 1 repetition.

If you succeed, you know that your 1RM equals this weight or more. After some recovery, you try to lift a heavier weight. Repeat this process until you fail to lift the weight. The highest weight that you are able to lift equals your 1RM.

1RM testing problems

There are several potential problems associated with 1RM testing. To name a few:

1. Injury risk: the original 1RM test requires a person to lift the heaviest weight they are capable of. If you do this with bad technique, it’s easy to injure yourself.
2. Timing: 1RM testing can be very fatiguing. This doesn’t always fit into your training program, since it affects future workouts.
3. Rehabilitation: if you’re coming back from injury or if you’re an older adult, absolute beginner, someone with a certain medical condition etc. 1RM testing might simply be a bad idea (if not impossible in the first place).

The list goes on, but you get the point: you want to know what your one repetition max is, but you don’t want to test it. 

“It’s better to know what an athlete is capable of – than to actually find out.”

Travish Mash

Luckily there’s a solution, which we will talk about in a minute! But first: here’s why traditional “submaximal” 1RM tests are “suboptimal”.

Submaximal 1RM test

A traditional submaximal 1RM test tries to solve the above mentioned problems. Here’s how such a submaximal 1RM protocol looks like:

Instead of doing a 1RM, you pick a submaximal weight and perform repetitions until failure.

For example: you start squatting with a 85 kg barbell. You keep going until you can’t do another repetition. Say you were able to do 7 repetitions.

As you can imagine, the number of repetitions with a submaximal load, gives you an indication of your 1RM. We’ll talk more about the procedure on how to calculate your 1RM based on a submaximal 1RM test. 

First we need to address a problem. Because with this submaximal test you still run into the same problems we mentioned in the previous section. Simply because this “submaximal” test is not submaximal. It requires repetitions until failure.

Plus the best predictor for 1RM is the number of repetitions performed at submaximal loads close to 1RM (e.g. 95%1RM for the bench press, according to this scientific study).

Doing such efforts can increase injury risk, they don’t always fit into your training program and they are not suitable for all individuals.

That doesn’t mean they are useless for everyone, all the time. So if you do want to perform such a submaximal 1RM test, simply plug your repetitions into a standard calculator:

Standard 1RM calculators

You can find many standard 1RM calculators on the internet. As we just mentioned, they require you to do a maximum effort test. 

Simply enter your barbell weight (e.g. 85 kg) and number of repetitions (e.g. 7) into the 1RM calculator, and it could say: “your estimated 1RM is 100 kg”.

Here’s an example of an underlying 1RM formula, according to this scientific paper*. It requires you to use a weight that you can only lift 5 times.

1RM formula

1RM formula: 1RM = 1.0970 x (5RM weight [kg]) + 14.2546

*This specific 1RM formula was created for a chest press exercise. The leg press formula turned out to be different (1RM = 1.1307 x (5RM weight) + 0.6999).

Are 1RM calculators accurate?

Yes 1RM calculators can be accurate, but as we’ve seen, science shows that the 1RM formula differs per exercise. Most 1RM calculators don’t take this into account.

Another aspect is that the 1RM prediction from a calculator is likely to be more accurate when you use higher loads. According to this scientific paper: “no more than 10 repetitions should be used in linear equations to estimate 1RM”. Which makes sense, right?

Summarised

Both traditional 1RM testing and submaximal 1RM testing requires you to do a maximal effort. Although it can be an accurate way to measure or predict 1RM, it also has some practical downsides. Let’s look at a third method to predict 1RM, that solves some of these problems.

How to easily predict 1RM, using velocity based training

Here’s something you can probably relate to. The more weight you’re trying to lift, the slower you move. This is the foundation of velocity based training.

Take for instance a bench press. When you use an unloaded barbell, you can move it very fast. When you’re close to your 1RM weight, the barbell speed is very low.

We can use this force-velocity (or: load-velocity) relationship to determine your 1RM. The best part: you don’t need to do any maximal effort. You only need to rely on the velocity based training principles.

Here’s how to calculate your 1RM, using velocity based training. According to this scientific paper, all you need to do is:

1. Measure your maximal (bar) velocity when lifting a light load (e.g. ~50% expected 1RM)
2. Measure your maximal (bar) velocity when lifting a heavy load (e.g. ~80% expected 1RM)
3. Draw a linear line between these 2 data points, similar to the image below
4. Determine your 1RM

Now before you do this, know that GymAware and FLEX have a built-in protocol in the app that estimates your 1RM. No need to do any calculations or estimations yourself. Learn more about this setup and protocol over here.

For now, let’s assume you want to calculate your 1RM, using the above mentioned 4 steps.

After finishing step 1 and 2, you have two points with both a load (x-axis) and a velocity (y-axis). You can now draw the linear line. Simply use a graph/grid paper and a pencil and start drawing. Or use a software tool like Excel. Here’s an example of how physical preparation coach Mladen Jovanovic used Excel to determine 1RM, using a force-velocity curve.

Make sure to make the linear line long enough. It should cross the horizontal x-axis. However, this is not where you determine your 1RM!

To succeed a maximal repetition, you need a minimum velocity. For the bench press, this minimum velocity threshold is 0.16 m/s, according to this scientific paper. As a result, your 1RM bench press is where your linear line crosses the 0.16 m/s velocity. In figure 1, this equals a load of 90 kg.

Get to know all minimum velocity thresholds via this article. Learn more about the underlying force-velocity (or load-velocity) relationship. Check out our velocity based training device, buyers guide.

Setup GymAware 1RM prediction

Using GymAware, maximum strength can be predicted for a given exercise without the need to go to failure. GymAware Cloud users can estimate 1RM very simply by collecting results over a range of lift weights and then selecting the 1RM report.

Here’s how to perform a 1RM prediction in the GymAware Cloud:

For the basis of this guide we will look at a bench press. In order to generate the ‘power & force/velocity profile’ it is recommended that at least 4 sets of 1-2 reps are completed each with a progressive load. As the load increases the bar speed decreases. As this is a sub maximal assessment, it is recommended that once bar speed drops below 0.5m/s you end the test and use the report to predict your maximum. 

To generate the report go to ‘finder’ > ’reporter’ then select ‘GymAware’, ‘athlete name’, ‘bench press’, and ‘test date’ from the four lists. Press ‘Generate report’ and in the report window select ‘1RM’ profile. Press ‘Generate report’ to view your graph and corresponding data.

4 tips to get the best 1RM prediction

Let’s finish with 4 tips to get the best 1RM prediction when applying velocity based training:

1. Complete a warm up before you start the protocol.
2. Always lift as fast as possible. Also when the load is below 70% of 1RM. Lifting with less than maximal intent at lighter weights will skew the results upwards, sometimes significantly. 
3. Execute all lifts at all loads with similar form. E.g. do not ‘shorten up’ your squats, as the weight gets heavier.
4. Adjust the Minimum Velocity Threshold for the exercise. Even better: adjust the Minimum Velocity Threshold for the individual as well.

What to do next

Calculating your 1RM without maximal efforts is just one way of implementing velocity based training. Learn more about velocity based training by downloading our whitepaper: How to get started with velocity based training [use case]. Get it for free:

Loek Vossen

Human Movement Scientist | Content Marketing and Education