This is a tricky question to answer, as it depends on a number of factors.
Usually when we visit a professional who deals with soft tissue and bone injuries and their treatment and rehab, we are given exercises to perform to aid our recovery. These exercises are so vital as they help tissues to repair and build strength, our joints to maintain or increase mobility and lubrication, our movement patterns to develop or reprogram and our nervous system to calm, regenerate and fine tune.
So how often and how many of the exercises on that sheet of paper should we be doing? First, lets start with frequency:
Frequency
This is how often you should be doing your exercises. This depends on the purpose and intensity of the exercise.
Exercises with a low load or intensity (i.e. exercises which are not about working to your full capacity) can be carried out every day. Sometimes even twice a day. Exercises such as mobility exercises and stretches may fit into this category.
However, exercises with a higher load, where the tissues are taken to their maximum capacity, should be performed less often. When working a muscle, or other soft tissues to their max, they need time to recover. This is actually where the magic of progress occurs. It is when we are resting that our muscles grow and strength develops. Push too hard, too often and you won’t get the same benefits. Weight training exercises to build muscular strength should be performed no more than 3 times per week. More explosive, or dynamic exercises, may only require 1-2 times per week, to allow sufficient rest periods.
Intensity
How hard you push yourself also depends on the reason for doing the exercise. If your aim is to build strength in a muscle, or muscle group, this will only happen if you work to failure. i.e. keep doing reps until you can’t do any more (with good technique of course!).
Exercises for mobility are not as clear cut. There is usually not a point of failure as contracting the muscles intensely is not the aim of the drill. The aim is taking a joint through it’s full range of motion and encouraging an increase in this range. So guidance here would be more based around your perceptions of increased mobility – i.e. when you feel a change has occurred. The same can be said for exercises such as nerve flossing and motion retraining.
Sports specific and proprioceptive drills are also not usually performed to failure and so a set number or timescale to work to will often be given. There should be a starting point and a target to help quantify improvement.
Reps
When it comes to strengthening, most of us will have heard the terms sets and reps. Reps is repetitions – i.e. the number of times you do an exercise. This is then repeated in a number of sets i.e. 3 sets of 15 reps – meaning you would do 15 repetitions, take a short rest 1-2 minutes; another 15, then a short rest again, followed by a final 15.
Presuming this is a strengthening exercise, the final set of 15 should be very hard work and if the exercise level is right for you, you should fail on or just short of the full 15 reps.
The number of sets and reps prescribed for you really depends on the intensions. A high number of reps tends to be aimed at improving strength endurance, for example 3 sets of 15-20 reps, which might be seen for an endurance athlete like a runner or cyclist. A lower number of reps with a higher number of sets (i.e. 5 sets of 8) is more typically used for building pure strength and muscle mass and therefore is less frequently seen in rehab plans. Rehab strengthening programs tend to be around the 2-3 sets of 15-20 range, with some exceptions.
Any good therapist will instruct you on how many and how often an exercise should be performed, as well as how hard you should be working and how to progress.