The Cascade of Failure
Gotta fail to succeed?
In this article we’re going to shed some light on something every personal trainer has to deal with in the gym – training to ‘failure’. When I came through my first PT course this topic was only lightly touched on at best. I always felt like there was something missing with the ol ‘spot em through a few more reps once they come to a grinding halt’ approach.
So when I discovered that there’s not only one type of failure, but three, the missing pieces fell in to place and my spotting improved (bigtime!) along with my clients results.
Before we move on to the three types of failure let’s quickly recap the main points from last time:
Around 7 out of 10 ‘typical’ personal training clients are unable to move well in the ‘big bang’ compound exercises due to musculoskeletal or ‘hardware’ limitations.- It takes time for your clients to develop the proprioception and reactions needed to perform new exercises in the gym well (remember the shaky, wobbly bench press?)
- Your clients need to practice so the nervous system can ‘learn’ the exercise, only then can you safely and gradually add load and/or speed to that exercise
- Fatigue and loss of concentration can cause an initially good movement pattern to get a bit ‘ugly’
- The brain is very task focused and will put us in to unsafe postures and positions during a tough set in order to carry out the initial instruction it was given – it doesn’t know what ‘good’ or ‘bad’ technique is
- You don’t need to train someone to failure to stimulate change, you simply need to introduce enough overload to stimulate some change and then keep that going over time
Ok, let’s move on to the three types of failure you’ll encounter with your clients in the gym:
What is the ‘cascade’ of failure during an exercise?
When someone is lifting their muscles don’t just give up, what happens first is a battle between their brain and the discomfort they are feeling.
Failure comes in different forms and really occurs as a cascade of events as follows.
- Tempo failure – the speed of different parts of the exercise change
- Technique failure – the alignment of the body parts change
- Supported muscular failure – two causes; energy system and/or neuromuscular / voluntary cessation (stopping) by the client
Tempo failure
Tempo failure is something you’ll see when a person does not lift at the same speed/timing as they did before, because they are becoming tired.
The brain does this quite naturally as it detects things are getting hard and makes them easier by accelerating through the easy parts of a movement, using the momentum gained to get through the harder parts of the movement. The brain essentially modifies tempo to achieve the easiest force profile required to get the bar from point A to point B as per the aim of the exercise. This change in tempo can be seen as bouncing, slinging, or any other ‘segmenting’ of the tempo across the movement. Basically, if the tempo the client is following isn’t the one prescribed by you, and the one achieved within the first repetitions of the set, tempo failure has occurred.
It’s important to start spotting (if you’re going to push the client to energy system or neuromuscular failure) at this point. It allows you to maintain the correct tempo, work muscles through tough parts of the exercise properly and be right there if your client’s brain decides to change technique or give up completely.
Technique failure
Technique failure is something you’ll see all the time. It’s where the brain has said “this is hard, these muscles are tired, but these ones over here can help”. The brain then rearranges the body to involve the fresh muscle mass and give the tired muscles a break.
The problem with technique failure is that the brain has no understanding of the risks its running until it’s too late. An example is when a person completing the standing shoulder press leans back to open the chest to the exercise so that the pectorals can add force and the deltoids can get some rest.
In order to do this the lumbar spine has to be put too far into extension jamming facet joints together and compressing intervertebral discs. If the person has a ‘kyphotic’ or rounded upper back posture and poor abdominal control this further raises the risk of injury. In fact, in order to adopt this posture the abdominals need to be released so the spine can extend, therefore by default you now end up with a weight up to a metre or more away from the joint around which it’s pivoting, usually the L3/L4 vertebra in the lumbar spine. Technique failure should not be allowed amongst your clients as injury risk exponentially increases, and the benefit to the muscles targeted decreases, whenever it occurs. Furthermore, what the brain begins to record is that under duress, when these muscles are failing, this is the posture to adopt to help out.
Nothing could be further from the truth. What you really want is the brain to be saying is; 'if I can’t lift if in this position, I won’t lift it at all'. You want your body to learn that in all circumstances for safe lifting this is the posture I should adopt.
As suggested above the fatigue being experienced in most agonist muscle groups involved in an exercise will cause the brain to look for options. Most of those options involve a change in limb and trunk position of some kind. That means the brain must relinquish control of some of the joint positions it has originally adopted, essentially meaning the synergists and fixators of the movement will modify their actions, allowing movement in planes and around joints that are unplanned. This is not what we want. We don’t want the stabilizers of a joint taking a little holiday when the going gets tough.
Fundamentally technical failure requires a relinquishing of joint stability and soon afterward the adoption of a higher risk position. If your client is changing their technique during a push up it’s likely their abdominal group has let go of their trunk, their lumbar is in extension, their upper back is rounded and they are trying to add deltoids into the exercise or shorten the path of the exercise by shooting the head forward toward the ground.
Good trainers know what changes will occur during technical failure and will already be spotting (as tempo failure becomes evident) and will add to that clever cues to remind the client to hold their technique even before their technique starts to waiver.
Supported muscular failure
This is where either the energy systems can’t provide enough ATP or the nervous system can’t continue to stimulate a contraction (either due to fatigue or reflex inhibition).
Supported muscular failure refers to a situation where the client is receiving spotting support and is maintaining technique. The spotting will be helping maintain tempo while the client is being cued on technique.
This allows the muscles to be worked beyond where they could be by the client independently. It allows this to be achieved with no relinquishing of technique or tempo. Typically this involves only one to three more repetitions in a given set beyond the start of tempo failure.
Remember that when tempo failure occurs the trainer may start spotting / assisting. Then the technique cues start – most exercises have only one or two areas where stability will be lost first, so it’s a matter of concentrating on those areas. Then the encouragement of the client to finish the last rep or two begins. Usually you’ll get one or two good reps after tempo failure and one or two good reps after technique is starting to become a real challenge.
The nice thing about supporting someone to lift properly and extending their lifting is that they learn to maintain technique under duress, and they quite quickly develop strength in the difficult parts of an exercise.
Every exercise has a point at which it is hardest. This is because of the biomechanics in play. This point is sometimes called the ‘sticking point’ of an exercise. Many exercisers ‘cheat’ at the sticking point either by modifying tempo and/or technique. They essentially train their bodies to avoid the hard part and as a result never develop strength in that range. It becomes a self-perpetuating cycle. It’s hard here so I cheat here so I don’t get strong here but I do everywhere else, so next time I do this exercise it’s even harder here by comparison.
To get the best results for clients you don’t need to jeopardize their safety, just guide them through tempo failure, get one more rep with good technique when they would prefer not to, and hey presto, your clients strength will progress nicely.