6th May, 2022


This post expands on the Progression section of the chapter named Exercise Prescription, at page number 376 of the book Conditioning for Strength and Human Performance. Autoregulation is a concept that is not described by any of the books in my reference library.

Defining failure

In the context of resistance training, failure can mean different things. In the textbook which this post expands, and even in the scientific literature, failure is often not defined and what it means is unclear. I propose the following two definitions:

Muscular failure is when the lifter accumulates enough acute fatigue to be unable to complete another repetition of a given exercise. It is the point where, despite the greatest effort, the athlete is unable to meet and overcome the demands of the exercise, causing an involuntary set endpoint (Steele, Fisher, et al., 2017). This means that the lifter would be unable to complete any more repetitions even if he tried, because the physiological exhaustion of biochemical resources in the neuromuscular system makes concentric contraction impossible.

Technical failure is when the athlete accumulates enough acute fatigue to be unable to complete another repetition of a given exercise without compromising technique. This kind of failure is the reference landmark that I utilize when prescribing intensity. In this context, technical 1-RM is defined as the heaviest weight the lifter can lift for one repetition for a given exercise with perfect technique.

Technical failure is the kind of failure I use as reference point for my training. Training within technical failure boundaries allows me to make sure that all the repetitions performed utilize the same technique, without compensatory movements involving muscles that are not intentionally targeted. When I look at my logs I can be certain that every repetition in my previous workouts was a good repetition, and that my ability to track progress is reliable.

Proximity to failure

Chronic fatigue happens when the athlete is unable to recover from the training stimulus and results in, among other symptoms, a decrease in performance (Bompa & Haff, 2009). Reaching failure causes unsustainable amounts of fatigue (Ramos-Campo et al. 2021), training to failure repeatedly and consistently should be avoided, while rarely and carefully training to failure is acceptable. If the trainee is a strength athlete, carefully planning training to failure is necessary.

While strength adaptations (hypertrophy, maximal strength, rate of force development) can be maximized by reaching failure (Fisher et al., 2011), training in its close proximity confers a similar degree of adaptations without the large amount of fatigue (Grgic et al., 2022). Training in close proximity to failure allows the athlete to keep acute fatigue from becoming chronic, and to train more frequently, accumulating more training volume in the mesocycle.

Prescribing intensity and proximity to failure

Proximity to failure can be expressed as percentage of 1-RM. Methods of prescribing intensity based on percentages of 1-RM are inaccurate because they assume the athlete’s performance is stable and that the athlete can perform equally as good at any time. Anyone who has trained in any sport must have experienced their performance being inexplicably better or worse than expected. This is because there is a large amount of day-to-day and intra-day variation, that goes beyond the training session and program.

Particularly in novice athletes, 1-RM performance is not stable as it improves very quickly even by just being exposed to the 1-RM testing protocol itself. The 1-RM measured can cause the subsequent prescription to be underestimating the optimal training load.

Proximity to failure can also be expressed utilizing subjective measures. One such subjective measures is the RPE scale, discussed in another book in my collection (Heyward & Gibson, 2014), traditionally been used for aerobic exercise but recently has also been used for resistance training. More recently, the analogous Repetitions in Reserve scale (Zourdos et al., 2016) has been shown to be more accurate than RPE for resistance training purposes (Helms et al., 2016). I call it Repetition Before Failure scale, or RBF scale, because it is easier for trainees to understand this name, in my experience.

The RBF scale is an intuitive method of expressing intensity for resistance training. Each RBF value represents the number of repetitions that would have been able to be performed by the athlete, were he to keep going instead of stopping the set: stopping the set at RBF 2 means that, were the athlete to keep going, he would have been able to perform 2 more repetitions before reaching failure.

The RBF scale has some limitations: novice lifters can wrongly estimate the proximity to failure by large degrees (Steele et al. 2017) and even experienced athletes can wrongly estimate the proximity to failure when the intensity required is relatively low (Hackett et al., 2012). Novice lifters can learn to better estimate proximity to failure but, taking into account the second limitation, it is best to avoid utilizing the scale whenever the target RBF value would be above 5.


Autoregulation is altering training variables based on the athlete’s feedback rather than inflexible predetermined changes. It is a method that helps the coach and the athlete to adjust intensity to the athlete’s own individual adaptations, physical and psychological condition (Mann et al., 2010).

The RBF scale is the tool that allows autoregulation: it allows the coach to prescribe the desired training instensity with more accuracy compared to relying on inaccurate and inflexible percentages of 1-RM, and it also allows the athlete to manage the number of repetitions and load to achieve the prescribed training intensity. Autoregulation based on the RBF scale takes into account the fact that there is variation in human performance caused by various factors such as psycholgical, nutritional, individual, etc.

Autoregulated double progression

It is a progression strategy that utilizes the RBF scale to achieve autoregulation. This strategy can be implemented for both maximal strength and hypertrophy training.

  1. The coach establishes the RBF range target and repetition range target, the athlete selects the appropriate load to fit those targets. A log is kept to record the RBF value, repetitions performed and load utilized for each set.
  2. With time, logged RBF values are expected to become higher, indicating that the athlete is in fact getting stronger. Repetitions are added to each set that requires it in order to stay within the RBF range target.
  3. When the number of repetitions to perform in any one set is too high to fit within the repetition range target, load is increased for that set.

Point 1 is what I call the setup, while point 2 and 3 are the two progression methods.