Updated: Dec 7, 2022
There has always been a back-and-forth in the fitness and strength community about whether or not to train to true muscular failure.
There seems to be enough evidence at this point in the game to make an educated choice on how hard you should be training in each session to make the best long-term gains without overreaching.
After laying out some of the latest findings from years of research, I'll give you my best recommendations that take into account the evidence combined with years of experience in training myself and training lots of clients throughout my career in the industry.
First, some definitions:
Disclaimer, this is how I view training to failure across two different training styles - I think it fits pretty well.
Training to failure (local): Performing a set to voluntary muscular failure. You have done as many reps as possible with that muscle and despite your best efforts, you cannot perform even 1 rep with reasonably good technique. Here, the muscle is the limiter. This kind of training is popular in bodybuilding type programs.
Training to failure (neurological): Your muscles cannot produce enough force to accomplish a task. Take this example; you are slowly building up to a 1 rep max in the squat and eventually can not perform a squat against any more weight. You have not reached muscle fatigue and have not taxed the energy system maximally but you simply cannot produce enough force to move a given load.
Let's examine some research on training submaximally compared to training to failure.
TRAINING TO FAILURE vs. SUBMAXIMAL TRAINING for HYPERTROPHY & STRENGTH
This is something that has gone back and forth for a while. Lately, there has been an abundance of research emerging showing that there is no clear benefit to failure training.
A recent systematic review and meta-analysis from Grgic, Schoenfeld, Orazem, and Sabol (2022) evaluated 15 different studies assessing the strength and hypertrophy effects from training programs taken to failure and those to "non-failure." The results of this large study concluded that, when total training volume was equated, there was no significant difference in muscle size or strength in either program.
This has been replicated several times in other, earlier reviews and in individual studies.
My practical take-away from this: training to failure is very taxing and fatiguing and *may* increase injury risk from pushing so hard very often. If there is no clear benefit from constantly training to failure then it would be better to train very hard, but with some reserve, so you can recover and then hit the next exercise and next session.
So... How Hard Should We Train?
I don't want this article to make it seem like you can just do the easy stuff and get great results, because that certainly is not the case.
Sub-maximal, non-failure training is really hard, and you will still be pushing yourself.
For maximal strength, higher loads seem to still be king. A good, rule of thumb is to frequently train with loads >85% of 1RM for 1-5 reps (3). That being said, strength gains can be made with less load and more reps, and vice versa.
For muscular hypertrophy, you can use moderate to heavy loads (greater than 30% 1RM) but need to come close to muscular failure. This makes the rep range you use highly variable. A lighter load will allow more reps to approach failure, and a heavier load will allow fewer. This range typically can be found between 6 and 12 reps when using loads between 60 and 80% of 1RM (3). A general rule of thumb, anywhere between 0-5 reps in reserve (RIR) can produce strength gains.
Numbers and percentages aside here's a really practical way to train.
I use the perception of rep speed to gauge whether or not I am pushing hard enough. When the rep speed significantly slows down, you are approaching muscular failure. Check out these two training clips and watch the rep speed of the first and last rep.
I have no idea what %max this is of my stiff leg deadlift, I had no idea how many reps I was going to do for this set. I just went until the reps got way slower and way harder.
Same here, no idea what % max this is of my meadows row. Just slapped on some weight and went for max reps until reps slowed down and required me to use a little English to finish the rep.
Any well-designed training program will put the bulk of your training within the above parameters while occasionally approaching muscular failure to ensure you are working hard enough and taxing the muscle fibers enough to encourage growth.
NOTES on SUBMAXIMAL TRAINING for CARDIOVASCULAR FITNESS
The current physical activity guidelines recommend engaging in vigorous cardiovascular exercise at 70-85% max heart rate for a total of 70-150 minutes per week to increase cardiorespiratory fitness OR 150-300 minutes of moderate cardiovascular exercise at 50-60% of max heart rate. (4)
This is definitely sub-maximal considering some of the intense metabolic conditioning workouts some folks do.
If you want to increase your cardio capacity to perform a specific task, like running a 400m race or competing in CrossFit, then that is a different story and that may require some threshold training that really, really sucks. Anyone that has truly trained like this will tell you how much it sucks and beats you up and takes time to recover from. The problem arises when every single workout is like that.
To quote one of my favorite, long-time clients... "I used to feel like a bag of shit after every workout," she said about her CrossFit days before training with me. Now, "I don't feel like a huge bag of shit after every workout."
My practical takeaway: you can get a great workout and improve your health and fitness with less, be able to recover for your next session, and not feel like a bag of shit all the time.
If you NEVER approach failure in your training, you probably need to work harder.
If you are ALWAYS approaching failure in your training, you probably need to take a step back most of the time.
Make sure you are working hard enough for hypertrophy - coming within 0-5 reps of failure when using loads between 60-80% for 6-12 reps
Make sure you are working hard enough for strength - the majority of lifting >85% 1RM for 1-5 reps with great technique
Make sure you are working hard enough for fitness - the majority of training between 65-85% MHR
Every once in a while, when the stars align, go nuts and go to absolute failure on a safe exercise or cardio effort
For more on gauging training intensity, check this out: Technical Failure Defined
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Thank you for reading.
(1) Grgic, J., Schoenfeld, B. J., Orazem, J., & Sabol, F. (2022). Effects of resistance training performed to repetition failure or non-failure on muscular strength and hypertrophy: A systematic review and meta-analysis. Journal of sport and health science, 11(2), 202–211. https://doi.org/10.1016/j.jshs.2021.01.007
(2) Schoenfeld, B. J., Grgic, J., Van Every, D. W., & Plotkin, D. L. (2021). Loading Recommendations for Muscle Strength, Hypertrophy, and Local Endurance: A Re-Examination of the Repetition Continuum. Sports (Basel, Switzerland), 9(2), 32. https://doi.org/10.3390/sports9020032
(3) Krzysztofik, M., Wilk, M., Wojdała, G., & Gołaś, A. (2019). Maximizing Muscle Hypertrophy: A Systematic Review of Advanced Resistance Training Techniques and Methods. International journal of environmental research and public health, 16(24), 4897. https://doi.org/10.3390/ijerph16244897
(4) Franklin, B. A., Eijsvogels, T. M. H., Pandey, A., Quindry, J., & Toth, P. P. (2022). Physical activity, cardiorespiratory fitness, and cardiovascular health: A clinical practice statement of the ASPC Part I: Bioenergetics, contemporary physical activity recommendations, benefits, risks, extreme exercise regimens, potential maladaptations. American journal of preventive cardiology, 12, 100424. https://doi.org/10.1016/j.ajpc.2022.100424