There are many ways to define failure in training.
Most commonly, this is the point in an exercise when you physically cannot complete a single further rep. This is Volitional failure, when you cannot - no matter how hard you try - perform a another repetition - you literally can't lift the weight back up without the assistance of a spotter or you crash into the safeties. Technical failure is the point where a lifters form **breaks beyond an allowable threshold, a set to technical failure is often audibly called by a coach watching on, this point is slightly below the volitional failure point.
The third failure point is psychological failure, the point at which we mentally give up on a set. The gap between psychological failure and true technical failure is highly variable, many general population trainers (known in the fitness industry as civilians) often have very low psychological limits, they struggle to accurately gauge how far away from the edge they are in any given exercise and have limited success using subjective RPE systems . This is not a criticism (I am a civilian in training terms, more on that later) but it comes from a lack of experience pushing their capacity both physically and mentally. Expressing strength is very much a skill and we like any skill it is improved with deliberate practice.
Many civilian trainers could actually be well served by training closer to their physical limits and pushing their comfort zones, something velocity tracking can also help with. You can see this in action with general gym goers
It takes a lot of mental toughness to truly perform a set that is indeed "maximal" and not just our psychological ceiling.
Using failure as a training variable
For the purposes of this article let's focus on technical failure for intemediate lifters and above, the kind of lifter who could probably guess their 1RM on most exercises with 5% on any given day.
For the experienced strength trainer; powerlifters, athletes, cross fitters and the like, proximity to failure is another variable to be manipulated. Some times you will want to work close to this point, expanding your physical capabilities and testing your mental limits. Then at other times, working too close to failure is actively avoided, deliberately ending sets a comfortable distance short of failure, working on the skill elements of lifting, tapering for competition, or enabling more recovery dependant on our training goals and time of season.
Proximity to failure is also commonly known as exertion, the level to which we exert ourselves on any exercise or activity. Taking the dog for a walk has low exertion, while a 2km time-trial is pretty close to maximum exertion. This exertion is independent of the intensity of a stimulus or the volume of an activity (although they do play an inadvertent role). A 100m sprint would be high intensity and maximal exertion. Walking 100km in a day would be high volume but also probably a pretty high exertion rating.
I like to think of failure as being the final point on the continuum of exertion. Absolute volitional failure is at 100% and the first warm-up of the day is at 0%. Between these two extremes there is plenty of grey area for how much exertion a set takes to complete. So before we continue, it's important to note that training to failure isn't isolated to exclusively complete failure, it could just be a high volume of training done very close to the point of failure working above 92.5% or above on our sliding scale of proximity to failure. This will be important when we talk about the negative effects of hard training like this.
How we measure failure
Failure on a single set is a product of intensity - how close we are to our 1RM, and volume - the number of reps we do for that set.
One rep at 100% of 1RM is a set to failure and
10 reps at our 10RM is also training to failure
The most common method for measuring proximity to failure is with an RPE or RIR system.
RPE - Rating of perceived exertion and RIR - Reps in reserve are different ways of subjectively measuring how close a set got to failure. RPE uses a 10 point scale with 10 being a maximal effort, anything below a 5.5 is considered a warm up. In RIR systems the scoring is flipped with zero (0) being a maximal effort, meaning no more reps to be given.
These subjective systems are incredibly effective and easy to implement for trained individuals with experience lifting weights close to their maximum (powerlifters for example), however it has limitations for less experienced general population trainers and in power training when loads are submaximal and sets stay far from failure.
An alternative system is to use velocity loss, or percentage fatigue across a set as a way of establishing proximity to failure.
Velocity loss describes the decline in velocity output across a strength set completed with high intent to move. It takes the change in velocity from the best rep (usually the first or second rep) down to the last rep of a set as a percentage decline. The greater the percentage decline in output the closer a lifter has come to failure. it is suggested that for strength exercises with loads above ~70% of 1RM a fatigue value of 40% correlates with the point of technical failure.
The effects of training to failure
Training needs to include some proximity to failure. Hard work is rewarded in the world of training, so be wary of reading the next sections and thinking you can get away with only ever doing warm up sets and hoping to become properly strong.
However - and this is a big however - training very close-to-failure (say RPE9.5, or 35% velocity loss) as a prolonged and consistent element of your program can be counterproductive to both short term fatigue accumulation and long term strength gains. Performing large volumes of this high exertion training leads to an accumulation of both nervous system and muscular fatigue. Small volumes of this stimulus is unlikely to have a negative impact on performance, say a single set or even a single session is easy enough to bounce back from, but we need to consider that each training session as a single brick on the path to improved strength and power. If too many of these individual training sessions are overly taxing, the negatives start to outway the benefits
In training, everything is a tradeoff. We must balance volume with intensity and choose to focus on only a certain number of physical qualities at once, or we will end up developing none. Going all out and training to failure on Monday might not have any consequences for that session but it will have trickle on effects later in the training week.
The above illustration highlights how this works over a theoretical training week. An athlete goes hard on Monday, working much closer to their point of failure. As a result the time it takes their body (in particular the nervous system) is much longer to fully recover and supercompensate from the workout than the athlete who trains at a lower level of exertion. Both athletes train at the same intensities (in terms of % or 1RM) but it is the athlete who works at lower exertions, with a lower RPE value for each set and less velocity loss in each set that is able to recover faster. This better recovered athlete is then able to train better on Wednesday and also Friday of that training week, accumulating more high quality training sessions and compounding their gains compared to the athlete who went to failure who spends most of their week in a hole.
Training to failure and short term fatigue
For field sport athletes, they often have competition every single week, and need to be fully recovered, or at least close to it. For these athletes, accumulating too much fatigue in the weight room can have very real performance effects come game time.
Here is a clear example of how training to failure might be doing you wrong, especially in the short term:
Gonzalez-Badillo, 2016 (1) looked at the effects of a single training session on jump performance in the immediate days following the session.
Two groups did a workout of either 3x8 or 3x4 and the researchers then monitored their jump height pre and post the session to see how their lower body power responded to the two different training stressors.
This graph is just a snippet from the paper, but when we compare both groups to their baseline performance (100%) its really interesting what happens next.
Immediately post workout:
Immediately after the training sessions, both groups dig a massive hole in their power. The 3x4 group loses about 20% of their jump height, while the 3x8 group loses in excess of 30% on their jump height. That could be as much as a 20cm drop for a 60cm jumper in the 3x8 training group.
48hrs post workout:
Two days after the session the group that did the smaller training session (3x4) has now actually supercompensated and has a higher vertical jump than they did in the baseline test. Mission accomplished, the training was effective!
Meanwhile, the 3x8 group is STILL showing signs of fatigue, with their jumps still about 5% off their baseline performance. For our theoretical 60cm jumper, they are now only jumping 57cm, so even two days after the training session they are still in the hole, with 3cm wiped off their jump potential!
If your goal is to increase performance or simply not to have your athletes be worse in the days after they train, do less reps, dig smaller holes and prioritise recovery.
Training to failure and long term progress
But if we always train that far from the point of failure, sure we might be well recovered come the weekend, but won't we gradually lose strength and power? The effects of long term prolonged training to failure are most relevant to athletes who compete on a less frequent occurrence, maybe track and field, powerlifting, CrossFit, fighting sports etc where athletes spend periods of time away from competition and go through multiple training phases before peaking for competition.
How do these athletes fair when training with lower exertions?
Izquierdo-Gabarren, 2010 (2) looked to answer this question with three groups of Kayakers following three different training plans for a block of upper body strength and power:
- 2x sets not to failure*
- 4x sets not to failure (20%)
- 4x sets to failure (40%)
The group that trained to failure completed almost TWICE the amount of reps as the submaximal groups, yet they saw 80% LESS progress in their upper body power than the easier training group. Showing that more training isn't always optimal.
Another study (3) on training to failure showed similar results
This one is another use of the classic 20% vs 40% velocity loss, and again it's a pretty clear cut advantage for the 20% group. The 20% group showed a better training result for all physical qualities compared to the 40% group, even when it came to type IIA muscle fibre profile.
Leaving a few reps in the tank is the smarter way to go about it.
Training to failure: A case study
It wouldn't be right for me to go talking about training to failure without showing what that looks like right?
So I performed a little self-experiment. a case study of n=1, taking a few sets of safety bar squats to failure and analysing the results from a velocity based training perspective.
In these two videos I took 90kg (1xBW) & 67.5kg (75% xBW) for a spin to technical failure. All in the name of science!
I ended up at 6 on the 90kg and 20 on the 67.5kg, probably the first time I have done more than 10 reps of any movement in possibly 4 years!
On both sets I reached only managed to reach 32-33% velocity loss, A little short of the typical 40% yardstick for failure.
There are a few possible reasons I was not able to reach 40% velocity loss:
- Maybe I'm not very neuromechanically efficient and therefore not as good at grinding it out?
- Or possibly squatting above parallel changes the fatigue relationship compared with the full range of motion squats used in research?
- It's also possible that for a set of 20 reps the % fatigue relationship changes, with energy systems becomes more of a variable than strength and efficiency factors.
I then did two sets of bench press to failure and got 50%+ fatigue on both sets.It is possible that upper and lower body exercises have different velocity loss characteristics
For the safety bar squats, on both sets there seemed to be an inflection point after passing 20% fatigue where the velocity drops at an accelerated rate. Some kind of fatigue cliff brought on by my training history of mainly low rep low RPE training?
The two sets also had quite different final velocities, probably because the set of 20 was becoming more of an energy systems issue than strength. The 90kg set ended at 0.32m/s, in good alignment with an actual 1RM test from December last year of 0.36m/s.
I wonder if a set of 10-12 would be closer to the 0.35 velocity in alignment with my 1RM velocity?
Avoiding failure in your training
So now armed with the knowledge that training to failure is probably slowing down your progress, you are avoiding regular max out sets. Instead focus on doing the bulk of your working sets around the zone of RPE8 with only 15-25% velocity loss.
But it doesn't feel like you are doing enough work right? How can we train hard but still avoid the trap of training to failure? Here are some new ways to approach your training for greater gains while avoiding the potential negative side effects of prolonged training into failure.
Do more work sets
A meta-analysis from 2005 (4) combined the results from 25 different studies exploring training to failure and found two key insights. Overall, athletes who performed more sets saw greater gains in strength for both submaximal and maximal training plans, but - and its a big but - submaximal training was an astronomically more effective strategy across all set numbers.
So whether you are a time efficient lifter squeezing in two quick working sets before work, or you bring a cut lunch to the gym for a six set squat super session, leaving a few reps in the tank for each set is going to lead to greater strength improvements.
Cluster set training
Another great approach to minimise fatigue accumulation in your training without compromising workout density is to use cluster sets (5).
Clusters are a reimagining of traditional strength training. It simply introduces more frequent short blocks of rest into the exercise, enabling you to maintain higher training velocities across the session. Learn more about cluster sets and VBT here.
The best part about clusters is that when they are planned correctly they can actually be a more efficient way to train, allowing you to:
- Lift the same weight
- Perform the same number of reps
- With the same total rest
All while achieving a higher average velocity across the session!
Who says you can't have your cake and eat it too?
This table contains a few example cluster arrangement that all workout to approximately the same 5-6 minutes of total rest.
These are just two examples of ways to increase the quality of your training while avoiding the accumulation of fatigue that can come from repeated exposure to failure. It is still important to challenge yourself in your training, spending too much time inside your comfort zone will slow progress just as readily as spending too much time outside of it. Finding this balance is part of the challenge that makes strength training so appealing to so many people.
References and resources
Gonzalez-Badillo, 2016. Short-term Recovery Following Resistance Exercise Leading or not to Failure.
Izquierdo-Gabarren et al. 2010, Concurrent endurance and strength training not to failure optimizes performance gains.
F. Pareja-Blanco et al, 2016, Effects of velocity loss during resistance training on athletic performance, strength gains, and muscle adaptations
Peterson, 2005. Applications of the Dose-Response for Muscular Strength Development: A Review of Meta-Analytic Efficacy and Reliability for Designing Training Prescription
Tufano, JJ, et al. 2016, Maintenance of Velocity and Power With Cluster Sets During High-Volume Back Squats