Does this sound familiar? 3 sets of 10, twice per day! Unfortunately, it is all too common to hear this out of a physiotherapist’s mouth, but why? You will never hear a personal trainer or a coach come out with these numbers. So what is the difference between injury rehab and normal training?
To explain the difference between injury rehab and normal training, I will need to start my story back at university to explain this weird disparity. So picture this, I’m in a lecture and we are all told, “so this is a strengthening exercise for your knee”.
Okay, got it. Wait, hold up! What is a strengthening exercise?
There isn’t one!
How do I know?
Certainly not from the university that’s for sure!
If you examine all the research on strength then you will find out, that what makes something a strengthening exercise are the parameters of an exercise and not the actual exercise itself. An example is to give somebody like Hafþór Júlíus Björnsson a deadlift and say, “there you go that’s a strengthening exercise and I would like you to do 3 sets of 10 of those twice per day with 10 kgs.” After he stopped laughing he would say that it wasn’t hard enough to challenge the body to build strength and muscle and he would be right. Even if we made him do 3 sets of 10 to failure twice per day with a weight to do this, then after 2 weeks he would be injured and overtrained.
So this protocol is either safe but ineffective to build strength or is effective to build strength but dangerous due to the volume of training. So either way, it is not great and it is not simply that a deadlift is a strengthening exercise because if you had him do the first weight to failure then he would be going for hours, which would be an endurance protocol. Now you could say that a deadlift is an endurance exercise.
The devil is in the details.
The reality between injury rehab and normal training is injury tolerance and exercise tolerance. Injury tolerance is how much load or stretch or volume that a given injury at a given time can tolerate without making signs or symptoms worse and exercise tolerance is how much somebody can tolerate without fatiguing them too much. This doesn’t change basic human physiology, to get a person stronger you need to work them hard enough, and by nature, if you work somebody hard then you can’t, and don’t, need to train frequently. So the aim of injury rehab is to train the person as hard as possible for the goal at hand but within their injury or exercise tolerance. So this raises several questions? What are the ideal parameters for strength, endurance, exercise tolerance and flexibility? How do you know what a persons’ injury tolerance is and where do 3 sets of 10, twice per day come from?
What are the ideal parameters for strength etc?
Generally, high loads relative to failure work best for strengthing effects due to specificity but the loading should not be the same for all people. Most people work out their training load on their 1 rep maximum or 1RM. This is the amount of weight that you can lift only once and not even twice. Heavy loads are required to induce strength gains according to Schoenfeld et al (2017) and this is not disputed for strength in the literature. It is advocated that 70% of a 1RM is the minimum to achieve the optimal strengthening effect but this is not an exact yardstick. Other ways to work out the load are based on either Reps In Reserve (RIR) or Rating of Perceived Exertion (RPE) for a given load in the rep ranges that you are planning on working. If you are experienced with this type of training then your body has built up a tolerance to the stimulus and so greater loads than a newbie would be needed. Below is a video going into more detail on this:
So this is not just about picking a random rep number, you need to be working close to failure, which means unable to lift the next rep. However absolute failure isn’t the place to take this. A study by Haun et al (2018) found that 4.4 Reps In Reserve (RIR) was the point at which the muscle-building effects started to significantly lessen. So as long as you are never stopping your set more than 5 reps off failure then this would be optimal. This would be around an RPE of 7 and above, any lower and you aren’t working hard enough.
For strengthening reps per set can even be as low as 1 rep per set but this is not advisable to do very often at all due to a poor risk versus reward of injury. The maximum rep amount per set should be around no more than 10 reps. This was highlighted by Kubo et al (2020) who compared strength between training at a 4RM versus an 8RM versus a 12RM and they found that the 12RM group didn’t get as strong as the other two groups.
An example set would be planning 8 reps in a set with an RIR of no more than 5. This would mean that you would want to be able to do no more than 13 reps if a gun was pressed to your head and using the RPE method you would be feeling 7/10 exhaustion at rep 8.
These will vary based on numbers per set. For example, say a powerlifter was performing doubles or 2 reps per set, then 3 sets of this would be insufficient as you will only have done 6 total working reps for that exercise and at the other end of the spectrum your wouldn’t want to do German volume training for strength, which is 10 sets of 10 reps as this would be 100 reps per exercise. Unlike building muscle strength doesn’t need high volumes of work per session the most important aspect is the load being heavy (Mattocks et al 2017). A more sensible approach would be having sets between 3 to 5 sets. So 2 examples could be 5 sets of 5 reps (25 total reps) or 3 sets of 8 reps (24 total reps) Both of these would be of a similar volume and neither is too low or too high in terms of total reps per exercise.
Rests between sets:
For strengthening full recovery between sets is the key, as the goal is to lift heavy every time within the rep and set amounts planned. Grgic et al (2018) found that 2 minutes between sets was enough but I think that this will depend on the RIR or RPE, the load, the type of exercise and the cardiovascular fitness of the person performing the exercise. For example, Bicep curls done with an RPE of 7 for 10 reps in a cross fit athlete would need less recovery time to perform each set well than a strongman performing a deadlift with an RPE of 10 for 4 reps. So you can’t fully generalise this to everyone and everything. I think the best approach is to listen to your own body and your actual performance. If you feel recovered and ready to go and you can do the same reps to the same RIR or RPE then you are good to go!
Once again, just as for volume this is not too much of an issue for strength as it would be for hypertrophy. In a study by Colquhoun et al (2018) they compared strength gains with one group training 3 times per week and another group training 6 times per week and found no difference when the volume was equal for the entire week. So high frequency isn’t needed nor high volume, you do need some volume per week but it is more quality (heavy) over quantity!
Range of motion:
Full range of motion of the exercise is better according to McMahon et al (2014). In this study, they compared full range of movement to partial range of movement and they even increased the load on the shortened range too. They trained 3 times per week over 8 weeks and overall they found significant differences between each group. The full range of motion group was superior to the short-range group. However, strength is functional so training into a range that you will never use or need is pointless but if you need strength in a certain range then you definitely need to train there.
The load chosen for an exercise to improve muscular endurance needs to be light to moderate and heavy training won’t be specific to the goal. For example, Anderson et al (1982) found that endurance actually decreased in the 6-8 rep 1RM trainers but improved with the low and moderate load trainers. Just like the strengthening protocols you need to work out your loads based on relative proximity to failure. Effectively, muscular endurance is attempting to build resistance to failure with adaptations such as lactate tolerance and threshold so training needs to reflect this.
The range here can be rather large because if you just think logically doing a thousand reps would require immense muscular endurance however, this may well be overkill! A more sensible approach is to work anywhere from 15 to 40 repetitions per set and this was supported in a study by Stone et al (1994) where they gained improvements in muscular endurance using this range of reps. Again remember the load needs to work with these reps to get very close to failure in each set.
As with strength, you can work 3-5 sets because although working more would need greater muscular endurance it would be very taxing on the cardiovascular system, which in itself isn’t a bad thing but this would become the limiting factor first. You would also overload the central nervous system (CNS) and vomit everywhere before you fully tax the local muscle for muscular endurance failure.
Rests between sets:
Short rests are a must but you do still need some rest otherwise you will be limited by cardio and your CNS and this would also place greater recovery demands on the body meaning either low-frequency training or overtraining. Being more specific, no more than 60 seconds rest between sets and 5 minutes between each different exercise is a good guide (Sedano et al 2013).
Now because loads are lighter then tissue damage and repair is not as much as heavy strength training but your CNS needs to recover before training again. So although the recovery element is different the recovery length should be the same provided that you are training correctly with the above parameters so like strength around 3 times per week would be giving balance and recovery time. This is backed up by Radaelli et al 2015), where they found that performance was reduced at 24 hours post endurance exercise but back to normal after 48 hours meaning 3 times a week would be about right.
Range of motion:
Just like strength, your individual muscular endurance range requirements will be individual to yourself and so training into a range that you will never use or need is pointless so only train the ranges that you will use for your sport or activity.
So exercise tolerance is how much exercise a person can manage in terms of their capacity. For example, somebody could be really strong but can’t walk very far and climb the stairs. It is a combination of cardiovascular and muscular endurance and the central nervous systems tolerance to activity and exertion. If somebody has been bed-bound then their exercise tolerance would be extremely low.
All the variables of normal training theoretically still apply but the persons’ tolerance of these variables won’t be there. This means that you need to train sub-optimally initially to build exercise tolerance first to effectively bridge the gap to optimal training variables. Basically, you need to adjust to their capacity. If their capacity is low then low load, low reps, low sets are sometimes the only place to start.
Often you will need to have easier exercise variables so that they are tolerated and you might need higher frequency bouts to compensate for this. This may be where something like twice daily or 3 times daily could be correct. The only true way to know is their response to training. If they aren’t wiped out and can gradually do more over time then you are working in their sweet spot and the aim is to build this up.
Eventually, you will move to higher intensities and with this, you should reduce training frequency (except stretching) until you are using the optimal variables for your goal, whether it be strength training or something else.
The first thing to note is that not everybody needs to, or should stretch, the only reason to stretch is that your muscles are too short for the movements that you use and need. Having shortened muscles could lead to decreased performance, abnormal movement and potentially injury. Now lots of research has been done on stretching and in itself, it doesn’t reduce injury risk but this doesn’t account for individual rationale. The take-home message is that everybody is different. It’s not a one size fits all and ideally, you need to be screened for your sport to see if have any range deficiencies to correct. This is very much something that we look at in our Physio sessions at our Stoke-on-Trent clinics. A big reason not to stretch unnecessarily is the fact that static stretching has been shown to reduce power and strength. Check out this video for more on this:
When people do stretch they commonly get it wrong, they stretch too hard and not frequently enough. Just think about this for a second, What is the stretch doing? It is stimulating growth and stretch tolerance and this is achieved by a light stretch. A hard stretch is more likely to overstretch the tissue and create microtrauma. In terms of frequency of stretching. If you think yourself about your normal day you would naturally apply a stretch to tissues of the body at various points of the day and if this amount were to lengthen and grow tissue then we would all be super flexible but we aren’t.
This means a higher frequency is better. An example of this is in pregnancy, where no women ever had their abdomen explode from the growth of the baby, did they? No the skin, muscles, fascia and internal organs all grew to a longer length to accommodate the growth of the baby and this stretch is light but perpetual. The closer to this you apply stretching the more likely you will be successful in your improved flexibility. I often advise patients to perform their stretches light and often and if I give them specific numbers then they are between 4 to 6 times per day but this is not always possible, so I tell people to do them as close to this as possible as best they can.
It is generally considered that a short hold time won’t improve flexibility but may maintain it and so if you are performing static stretches to improve your flexibility then 30 seconds hold times are effective and this was shown to be the common time held in a study of premier league clubs (Dadebo et al 2004).
How do you know what a persons’ injury tolerance is?
Injury tolerance is similar to exercise tolerance but instead of their capacity to manage activity or exertion, it is how much their injury can tolerate without worsening signs or symptoms. So a person could be strong enough to lift 50kg but their injury will be stirred up by this so they need to work at their injury tolerance level, which would be lighter. However, the aim is to build their tolerance to their load capacity gradually over time to then optimally train for their actual goals.
Now there are generally 3 protocols for injury rehab tolerance building:
Sign and symptom-free exercise while performing the exercise, after it and by the next day.
Signs and symptoms increase mildly or moderately while performing the exercise, but it settles back to pre-exercise state after finishing and is also fine the next day.
Signs and symptoms increase mildly or moderately while performing the exercise, this lasts for up to 24 hours but then settles back to pre-exercise state after this.
Below is a video discussing Hamstring rehabilitation, where Hickey et al (2019) compared pain-free and painful protocols to see what worked best:
Now, these are guideline ideas and how you approach this will be variable based on the person, the injury and the injury state. For example, an acute injury may want to be trained without pain increase due to structural fragility and somebody with chronic pain and hypersensitivity may want to train with the first pain-free approach as to not reinforce pain pathways etc. On the other side of the coin a tendon problem, which has low nerve supply could theoretically be trained painfully. The key to this type of approach is to see that the body adapts to the stimulus. As an example, if you train and get pain that increases to 4 /10 for 20 hours then it goes away this could be fine but you need to repeat this training next time and monitor the pain intensity and length. If the pain is higher or lasts longer then you are training above your injury tolerance and will have to drop back on some variables. If your pain decreases and lasts for less time then you are in the sweet spot and improving injury tolerance.
As you build your injury and exercise tolerance level up you will slowly be working into more like ‘normal training’, so you will be limited by difficulty rather than signs or symptoms. So as you work towards higher intensities you should just the frequency and rest periods accordingly.
Where do 3 sets of 10, twice per day come from?
The Physio Tools software is most likely the culprit because physios will just print what is already entered in the computer and this is 3 sets of 10, twice per day. Also, the fact that rehab is much more of a grey area compared to normal training makes it hard to teach to students. Black and white definite information is easier to teach and remember but is too generalised to apply to each individual person and their problem. The final reason that I propose is that much of NHS workload is of people with poor exercise or injury tolerance and this can be more appropriate in these instances. The problem is that there is often no progress towards the optimal variables as they improve tolerance. I have seen people in the past that have visited our Physiotherapy clinics in Stoke-on-Trent and they tell me that they improved initially and then plateaued. The reason is they never moved their exercise on to the next level for their goals. This especially true in sports and this is why this thinking is very important to define the difference between just a physiotherapist and a sports injury physio. If you ask me though they are the same thing or should be interchangeable at least.
So in summary, what is the difference between injury rehab and normal training?
Theoretically nothing (sort of) because if you want to get somebody stronger whether they are injured or not or you need to get somebody improved flexibility, injured or not, then the human body still responds optimally to the variables researched and tried and tested on athletes.
If a person is injured or has low exercise tolerance then you have to work to these restrictions first and these cannot be ignored. As you build up injury or exercise tolerance levels then you should gradually move towards the more optimal variables, which means progress should accelerate. So really there is no reason that physiotherapists should ever be giving precise pre-conceived ideas on what their patient should do, ultimately it is the body that you should listen to and progress based on this and this alone. Also giving a patient an exercise and saying this is to strengthen may technically be incorrect and in fact, it is probably more accurate to say that this exercise is going to improve your injury or exercise tolerance so that we can progress you to strengthening when ready.
Anyway, hopefully, this clears up the question, “what is the difference between injury rehab and normal training?”
The content in this blog article is provided for general information purposes only and is not meant to replace a physiotherapy or medical consultation.