The MISSING rehab exercise variable…..DOSAGE! (Ps…its not 3×10!)

DOSAGE! It is a subject that is not often discussed but may make a HUGE difference in the success of using movement and exercise during rehab. Perhaps MORE than the exercise itself!

Article at a glance


  • Dosage is a big deal
  • Intensity, volume and frequency all affect dosage.
  • Both over and under dosing are issues.
  • Try to find minimal effective dose. It can always be progressed.
  • Shared decision making helps find tolerable/effective dose.
  • Define what the right dosage should feel like.
  • Give a regression and progression.
  • Offer support to manage dosage.


Doctor holding heap of drugs in a hand

What is dosage?


Simply put, it is intensity, volume and frequency!

Intensity will be affected by the amount of weight we used or how fast we move the weight; both will affect the amount of force applied to a tissue and this is simply expressed as F = MA. The individual measure of intensity will be moderated by someone’s current tolerance.

The amount of repetitions and sets defines the volume. This can be manipulated and will have an affect on the overall overload.

Frequency is another aspect. You could have the most applicable exercise but if we do it 10 times a day (you have all had THAT person) that could be TOO MUCH of a good thing. So an exercise focused on changes in movement skill or quality (whatever that is!) could be done MORE frequently potentially than an exercise focusing on tissue load where you need time for POSITIVE adaptation to occur at a cellular level.

We can manipulate all three to achieve the desired response. Much more than 3 sets of 10 I am sure you will agree! The reasoning process behind movement/exercise is as important as any other aspect of rehab but not always considered.

This could be increasing intensity and decreasing volume, or increasing volume while decreasing intensity, or leaving those the same and changing frequency. There are a whole bunch of ways that dosage can be manipulated for large or smaller changes in overload.

Smaller changes can be REALLY important to get positive affects as large changes in dosage could have the opposite negative outcome. I have ballsed up a few times by changing the intensity in terms of load and not decreasing volume and have had negative outcomes.

Under dosing


If we under dose then potentially we will get no real adaptation. If you are looking for a change in whatever targeted aspect you are aiming for, lets say strength or load tolerance, if your manipulation of the variables is not on point then you won’t get much adaptation.

The caveat here is maybe there is no need to change the targeted aspect. Many studies have shown NO change in kinematics, posture, ROM or strength but a change in pain.

The caveat to the caveat might be that we don’t often measure the long term trajectory of injuries meaning that although we have a short term successful outcome in changes in pain that show up in studies many people often still suffer longer term with reoccurrence of an injury. This is different to chronicity because it may not be continuous and hence why it is often hard to simply define painful problems as acute or chronic. Perhaps we need some adaptation to affect these things longer term, but I am just thinking out loud.

Perhaps we are altering things we don’t or cannot measure such as local physiology, cellular adaptations, neurophysiology (nociceptive apparatus) or central changes such as can happen in the cortex with sensory and motor representations.

Under dosing could be frustrating as it is less likely to have an effect on the problem and not speed up (if we ever do!) the process of feeling better. This is potentially why we have seen a rise in the use of strength training as with a greater load we are less likely to under dose.

Over dosing


The opposite end of spectrum is giving too great a dose. To a sensitized system this could most definitely be an issue and cause an adverse response and could be why many therapeutic exercises are quite low in the overload stakes using minimal body weight or therabands.

Making someone’s pain worse can have a real effect on how they perceive the care you are giving, your competence and therefore the therapeutic relationship and trust bond. It is also really quite frustrating for them, people want to be able to get back to the activities they enjoy, they want hope and this is often fostered by progression.

Unfortunately it is very difficult to gauge what someone’s response maybe. Much like pain itself this will be dependent on many factors occurring in someone’s life at the this precise moment in time from stress to sleep to their emotional state.

Everybody has managed to make someone worse with a really minimal dose and also thought they have may have crossed the line with too great a dosage to find out that the person handled it just fine.

In reality we never really know where that line is!

Minimal effective dose


A minimal effective dose simply is trying to find a dosage that you think will cause an overload on whatever you are trying to effect but minimizes any potential for side effects. Remember you can always incrementally increase or decrease dosage later.

20 ibuprofen would get rid of your headache but would also expose us to other potential complications. So 2 tablets, or 200mg, is deemed a dosage that is effective but reduces complications.

Unfortunately the biochemistry of medication seems to be more generalizable across the population OR has been more widely studied with large clinical trials. Exercise dosage is still something that needs to be better quantified in the research base.

We could do this through looking at the person’s previous history such as chronicity or frequency of the same injury, the amount of a stimulus that may aggravate their problem such as time or load and then how long it takes to settle down after it rears its ugly head. If you flair your back up when picking up a biro and it takes 3 days to calm down then the dosage should reflect this, especially initially.

We can then adapt the intensity it terms of weight, speed or reps or the frequency of how often they do the exercise(s).

How can we make our dosing more effective?


Firstly we should think about shared decision making and discussing the potential outcomes of the variables being manipulated.

This helps people be better informed, and able to rationalize, what is happening to them especially if we explain WHY they may be feeling what they are feeling and what this ACTUALLY means for them. This hopefully avoids any uncertainty to be filled in by misinformation or investigation on the internet.

Explain that rehab is not a linear process and we don’t always know what the correct dosage should always be, hence why they need to be an active participant in the process.

All of this hopefully adds up to a greater internal locus of control.

Actually perform the dosage, or new dosage, with them and find out how it feels and how comfortable they are with it. If we are adapting a dosage then ask if they feel more comfortable increasing intensity, volume or frequency. Sometimes they maybe more willing to add more load than more reps or sets and sometimes the other way around, maybe they are happy now to do them daily rather than every other day.

Secondly the ability to independently manipulate dosage can be a really big deal. Often there are weeks between contacts so a dosage that is ineffective or aggravating could go unchecked for quite a while.

Here are my 5A's of self management.


Even in the face of increasing pain many folk STILL keep going with their exercises. They blindly believe that it will still make them better, hence if we arm people with some knowledge about what they should be feeling they could limit or adapt what they are doing and minimizing adverse effects.

Part of any exercise prescription (I hate THAT word BTW in relation to exercise) should be the ability to regress or progress based on an agreed level of discomfort, e.g. exercise soreness or actual pain. This could be based on a VAS score or some other personal measure.

If an exercise really hurts, both immediately or 24hr response, could you regress to an isometric? Or if already an isometric could you regress to a lower level of effort or frequency?

If it is not having much of an overload, perhaps gauged by muscle soreness, then could you add in more weight or reps and sets or how often it is performed? Again this offers people a greater internal locus of control.

Offering people support BETWEEN appointments could also be another way to better manage dosage and done via phone or email.



  • Dosage is a big deal
  • Intensity, volume and frequency all affect dosage.
  • Both over and under dosing are issues.
  • Try to find minimal effective dose. It can always be progressed.
  • Shared decision making helps find tolerable/effective dose.
  • Define what the right dosage should feel like.
  • Give a regression and progression.
  • Offer support to manage dosage.







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