How accurate are people at predicting repetitions in reserve? | Biolayne
  1. Reps
  2. Issue 13
  3. How accurate are people at predicting repetitions in reserve?

How accurate are people at predicting repetitions in reserve?

Accuracy in Predicting Repetitions to Task Failure in Resistance Exercise: A Scoping Review and Exploratory Meta-analysis
Halperin et al (2021)
REPS: How accurate are people at predicting repetitions in reserve?

Training close to failure seems to be pretty important for muscle growth and muscular adaptations in general. Knowing whether you’re really training close to failure is therefore important for your training to be actually effective without risking leaving gains on the table. But are people accurate at predicting their proximity to failure?


What did they test? The authors reviewed the currently available literature to explore how accurate people are in predicting their proximity to failure.
What did they find? On average, people could predict their proximity to failure with relatively high accuracy, being roughly 1 repetition off from a “perfect” prediction.
What does it mean for you? Certain caveats are discussed within the article, but overall, occasionally training to failure is still a good idea to ensure that your ability to predict repetitions in reserve is accurate.

What’s the Problem?

As we’ve discussed in previous REPS issues, working in relatively close proximity to muscular failure is important for both muscle growth and strength adaptations. Allow me to note, that training relatively “far” from failure, ie, 4-6 repetitions away, can also lead to strength and hypertrophy gains 1, and such proximities to failure have their place in training too. However, regardless of your proximity to failure, it’s important to have the ability to predict how many repetitions in reserve you have accurately. Knowing whether a set is truly close to failure can not only impact your gains but may also make it difficult to track progress, as you may be working less hard than you think, leaving pounds or extra reps on the table when they are there for the taking.

I’m sure many of you remember some of the first days in the gym, where you’d think that your set is over, but then your workout partner would tell you to get 5 more reps, and you’d somehow manage. The discomfort can often mask one’s ability to gauge how close they are to failure, especially during higher repetition sets and compound lifts involving multiple muscle groups. We often see the above phenomenon even with advanced trainees, who will often manage more reps than they feel they have in the tank, just because they were either pushed to do so or because they had their mind set on a specific number of reps they want to hit. 

As a coach, I often work with individuals of all training levels who find it difficult to gauge how close to failure they are, with some either barely making alive under the bar while claiming they still had a few reps left in the tank and others completing sets that look like warm-up sets but claim they were just right before hitting failure. For both of the above extremes, having them take a set to true failure, ie: the point where they’re unable to complete another repetition despite attempting to do so, usually helps them “calibrate” their proximity-to-failure compass, often resulting in a surprised reaction as they realize that they were not as accurate at predicting as they had thought they were.

But my anecdote does not mean a whole lot by itself as my personal experience may not really represent how well people gauge their proximity to failure in general. Which brings us to this study.

2 years or so ago, our lab in collaboration with Dr. Halperin’s lab from Israel, looked at the accuracy in predicting repetitions to task failure in resistance exercises. In other words, we looked at how good people are at gauging their proximity to failure.

The results may surprise you!

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About the author

About Dr. Pak
Dr. Pak

Pak is the Chief Editor of REPS, an online coach and a researcher. Pak did his PhD at Solent University in the UK on “the minimum effective training dose for strength”. As a Researcher, Pak is a Visiting Scholar in Dr. Schoenfeld's Applied Muscle Development Lab in New York City. Pak's research focuses on all...[Continue]

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