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In Conversation with James Fisher and James Steele (part 1): Do you train to TRUE muscular failure? Understanding perception of effort, discomfort and intensity

Are you training to true MMF or is your perception of effort and discomfort holding you back? Read on to find out.
This is the first in a series of blog posts inspired by and featuring recent conversations with James Fisher, Senior Lecturer Sports Conditioning and Fitness at Southampton Solent University, and James Steele, Principal Investigator at UK Active Research Institute; Associate Professor Sport and Exercise Science at Southampton Solent University.

Intensity in HIT

The “I” in HIT stands for Intensity, which practically speaking means reaching momentary failure (MF). The point at which a load can no longer be lifted, when dynamic movement becomes an isometric contraction, represents 100% intensity: the HIT Gold Standard.

We recently spent a day in Southampton with James Fisher and James Steele, discussing their research.


An Agreed Definition of Intensity?

When conversing with a wider audience there can however be a challenge, potential for miscommunication, in the interpretation of the term used. As James Fisher, James Steele and others have pointed out, there are trainers and researchers who associate the term “intensity” with the percentage of a 1 Rep Max (%1RM) being used during exercise. A 1RM is the most weight an individual can lift for one single repetition of an exercise. A percentage of this load is then often used for a given number of reps in research papers and in training routines, such as 80% 1RM x 8 reps.

Load is Not Intensity

You may see researchers and trainers referring to the “intensity” of a set being 80% of a 1RM or 65% of a 1RM and so on. However, the %1RM used in an exercise is not necessarily representative of the actual effort level required to perform a set of that exercise. For example, if a researcher notes that all subjects performed 8 reps of knee extension exercise at 80% of 1RM, it is problematic to say that all subjects trained at 80% intensity. Some subjects may get close to MF at 8 reps with this load, others may be a significant way from reaching MF. The intensity of effort required to perform 8 reps at an “intensity” of 80% of 1RM is variable between individuals- the stimulus level is therefore not equal amongst all individuals.

If instead all subjects were instructed to train through to MF with 80% of 1RM, effort will be the same between all subjects. Effort will be maximal and in HIT terms, intensity will be 100%. Therefore the actual load used in an exercise plays a secondary role to the level of effort required to lift it at the point we terminate the set.1


When HIT advocates say “high intensity” we mean “high intensity of effort” or simply maximal effort.

Effort or Intensity

Perhaps the term “effort” serves us better than “intensity” to help avoid misunderstandings between various camps in the strength training community. When HIT advocates say “high intensity” we mean “high intensity of effort” or simply maximal effort. James Fisher defines effort as “the amount of physical or mental energy being given to a task” and more specifically in the context of resistance training, going to MF means “maximal effort being given to lifting a load… but unable to complete the task.”

MF is of course the classic endpoint goal of a HIT set, but there are other points in a set that can and have been used as endpoints in various approaches to strength training. Let’s take a look at them.


Possible Endpoints to A Set of Exercise

  • Nonrepetition Maximum (nRM)– you stop the exercise after a predetermined number of repetitions, despite having the ability to perform more reps.
  • Self-determined Repetition Maximum (sdRM)– exercise is stopped when you think you have performed the last full-repetition possible (i.e. you believe you would reach MF on the next rep)
  • Momentary Failure (MF)– you cannot complete the current repetition with correct technique
  • Momentary Failure Plus Advanced Techniques (MF+)– after MF has been reached the exercise is extended with additional advanced techniques (such as drop sets, forced reps etc.)

According to Steele, Fisher and other researchers, “MF represents the point of maximal effort as it is the point where, despite the greatest effort, a person is unable to meet and overcome the demands of the exercise”. 1 Achieving MF in a set will always represent 100% of possible effort, or put another way maximal effort is achieved by reaching MF in an exercise.2 Which brings to question what level of effort is required to best stimulate hypertrophy and strength increases?


The Best Endpoint?

Exercising to nRM may not provide a strong enough stimulus for the adaptations we seek. Whereas working to sdRM may be, but MF may stimulate better results overall than sdRM, at least within a single-set model. 1 James Fisher notes that it appears advanced trainees do get a greater adaptation in going through a set all the way to MF. He also points out that “True MF may be important because it is difficult to know where else to stop.” It is also worth noting, that MF+ does not appear to stimulate any better physiological results than MF.

James Steele adds that there may be a threshold for optimal results just before MF or just before maximal effort is reached, but research cannot currently define this point if it even exists: his advice is to “Push towards MF… and get there if you can.”


Actual Effort vs. Perception

There is another important issue related to stopping a set before MF has been reached, that of perception. In exercise, there is actual physical effort and then there is your perception of effort and other related feedback, such as perception of load and perception of discomfort. All of which are factors that can impact your performance of an exercise and the actual physical effort level you reach in a set.

James Steele points out that actual effort is “centrally generated by the brain and doesn’t rely on sensation or feedback coming from the muscles.” He elaborates that actual effort relates to a signal from the brain that recruits muscle, whereas “perception is something different and doesn’t necessarily match up with effort.”


In exercise, there is actual physical effort and then there is your perception of effort, perception of load and perception of discomfort, all of which are subjective.


This can be problematic in exercise that is stopped at any point prior to MF because we tend not to be very good at matching our perceived effort with actual effort. We may stop a set far further from MF than we believe we have, due for example, to the perception of discomfort. Remember, discomfort is not effort. This brings in to question the validity and value of ratings of perceived exertion (RPE) scales, where an individual is instructed to exercise to a certain level of perceived exertion. 3


Can you predict when you will reach MF?

As trainee’s who have performed HIT for a significant amount of time, you may be better than many at predicting how close you are to failure. However, I’m sure you have had the experience of grinding out more reps than you thought possible, surprising yourself with a couple of extra full reps after thinking the set was done. At the other end of the spectrum too, you may have had the experience of seemingly cruising through a set, surprised when out of the blue you suddenly hit MF prior to your expectation. As seasoned HITers if we can’t accurately predict when MF will occur, what chance does a novice or someone with less experience have?

Velocity Loss as a Marker of Effort

Are there any reliable markers that can tell us we are close to MF prior to it happening? Research led by Paulo Gentil, in which both James Steele and James Fisher were involved, suggests there is: movement velocity loss. This research (3) revealed that when exercising with a 2/2 rep tempo and 75% of 1RM load, velocity loss happens at a specific point in the set- the second from last full repetition.

Penultimate Full Rep- the first rep in which velocity reduces

Ultimate Full Rep- velocity reduces significantly more than in the previous rep

Momentary Failure Rep- movement slows to a halt during the concentric

The researchers point out that the velocity loss observed of ~20% that precedes failure is easily perceptible and that “This kind of velocity loss represents a significant degree of fatigue.” So, under these conditions when the rep perceptibly slows we can know that we are within a rep or two of MF.

A further interesting point to come out of this velocity loss paper is that despite the slowing that was observed in the 75% of 1RM group, there was another group who did not display velocity loss prior to the MF rep. This other group used 50% of a 1RM, it appears that lighter loads may not cause any significant slowing in exercise performance prior to the MF rep itself, which may make going to true MF all-the-more important when using lighter loads.


The Essence of Effort

Maximal effort occurs in strength training when we intend to continue to lift a load at the end of a set but are unable to complete the task with correct technique.

The “High Intensity” in High Intensity Training is equivalent to Maximal Effort and is achieved in continuing an exercise to the point of Momentary Failure.

Simply stating a certain % of a 1RM is used in an exercise is not meaningfully representative of intensity of effort, as load used is not directly indicative of the effort level reached in a set.

Rate of Perceived Exertion scales can be misleading because perception of effort, perception of load and discomfort are not the same as actual effort.

With loads above a certain threshold, notable velocity loss can tell us when we are within a rep or two of Momentary Failure. However Momentary Failure remains the gold standard endpoint of a set and reaching maximal effort may be required for stimulating best results particularly within a single-set approach to exercise and for advanced trainees.


1. Steele, J., Raubold, K., Kemmler, W., Fisher, J., Gentil, P., & Giessing, J. (2017). The Effects of 6 Months of Progressive High Effort Resistance Training Methods upon Strength, Body Composition, Function, and Wellbeing of Elderly Adults. BioMed Research International, 2017, 1–14. doi:10.1155/2017/2541090
2. Steele, J., Fisher, J., Giessing, J., & Gentil, P. (2017). Clarity in reporting terminology and definitions of set endpoints in resistance training. Muscle & Nerve, 56(3), 368–374. doi:10.1002/mus.25557
3. Gentil, P., Marques, V. A., Neto, J. P. P., Santos, A. C. G., Steele, J., Fisher, J., … Bottaro, M. (2018). Using velocity loss for monitoring resistance training effort in a real-world setting. Applied Physiology, Nutrition, and Metabolism, 43(8), 833–837. doi:10.1139/apnm-2018-0011

8 responses

  1. By the way, the links in the follow up email that comes to confirm my wanting to be notified of additional comments don’t work for me, for some reason

  2. Another factor could be limitations in equipment. You may fail at a sticking point where strength curve tends to have significant sticking point whereas a better strength curve or a little assistance to get over that point may well permit several additional reps. Also load may be a factor in that if too heavy, MF could come too soon. If I used my actual 1rm + 1% (bit of an extreme example to make a point), I could reach MF part way through first rep but doubtful that this would be effective stimulus, not to mention inherent safety issues. Great blog post.

    • Interesting comments. Research around strength curves has shown it makes no difference (an old study changed out a cam for a circle on a knee extension machine which meant failure occurred at a different point in the ROM because the load didn’t drop off). I’d bet there were perceptual/subjective differences but nothing from a strength point of view. The same with very heavy loads. The reality seems to be that reaching failure is failure no matter how or when it happens. For example, even maximal static isometric contractions, or co-contractions of elbow flexors and extensors seem sufficient and likely as good as anything else. I know this flies in the face of HIT love of Nautilus, MedX, etc. But I would say that they are experimentally more beneficial rather than necessary for optimal adaptations. Added to which we cannot know the strength curve of each individual and adapt a machine to suit it… based on internal biomechanics there will be (even very slight) heterogentiy in strength curves.

    • Hi Richard,

      You make a great point regarding load.

      Despite requiring maximum effort, performance of a single 1RM is not a good stimulus for hypertrophy. In a further part of the interview James Fisher notes that within a single-set approach you probably need the set to last at least ~30 seconds.

    • If I’m understanding, Simon and James, then a static isometric contraction as long as it lasts at least 30 seconds, would be as beneficial from a hypertrophy standpoint as a sophisticated machine? (except, of course for limitations in the ability to measure progress). thanks for comments

      • Isometric contractions do stimulate hypertrophy, whether they can to the same extent as dynamic exercise (and provide all the other benefits of dynamic exercise), over the long-term is unknown at this time.

        I typically only use isometrics when/if there is something stopping me from using a dynamic exercise for a particular muscle group. When doing an isometric I will perform it in the mid-range as this improves strength through more of the range of motion than at shorter muscle length positions.

        • Hi, guys. I’m a little late to this, but it concerns what I consider to be an interesting topic: isometric exercise. Several months ago I started doing a bicep curl timed static contraction. I have never felt quite right doing a curl on a barbell, dumbbell, or any machine. A timed static contraction where my forearms are just slightly above parallel to the floor just felt like the biceps were really firing. There is no question this has yielded the best results for my biceps. The only drawback I see is the lack of a way to track progress. I’ve increased the time of full effort, but it’s still not the same as dynamic exercise with weight and reps you can track. My anecdote says that isometrics do stimulate hypertrophy. My biceps have definitely improved since starting this.

          • Lack of tangible external feedback is probably the only real downside here as you mention. You can only simply make sure that over the course of the set you have meaningfully challenged the muscles resulting in full motor unit recruitment for an adequate time by the time you end the set. Without external feedback this mostly comes down to mindset, focus and genuine effort. Picking a mid-range position as you have with the biceps helps get the most out of isometrics in terms of strength gains through the widest range of ROM and stimulus for hypertrophy.

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