Therapeutic exercise is such a foundational aspect of therapy that its complexity often gets overlooked. An examination of charts in many clinics would reveal an ever-expanding list of exercises chronicling the progression of therapy. Periodization at best presents as some variant on the principal of progressive overload applied to a routine set/rep scheme. Loads max out with the heaviest theraband or dumbbell in the clinic. Exercise selection varies widely with EMG data playing a major role for some while others take what they consider a more functional approach.

In the book The Hitchhiker’s Guide to the Galaxy, the people ask a supercomputer, “What is the meaning of life, the universe, and everything?” The computer takes a very long time before finally replying, “42.” When those asking the question complained that this was a terrible answer they were told, “The problem, to be quite honest with you, is that you’ve never actually known what the question is…once you know what the question actually is, you’ll know what the answer means.” This is a humorous example but reflects a common approach to exercise prescription. Too often, answers (exercise type and dosage) are given without a clear understanding of the question (the specific adaptations desired). Exercise programming is predicated upon knowledge of the goal and the methods necessary to achieve it. Thoughtful exercise prescription rarely begins with the specific exercise. Instead, it starts with the establishment of specific goals. Then, dosage is selected based on the established goal and the patient’s presentation. Finally, specific exercises can be selected based on equipment availability, target tissue and/or movements, and any other contributing factors that have been identified.

Just because something can be done doesn’t always mean it matters.

Unfortunately, establishing the goal may not always be straightforward. The actual significance of many objectives is surprisingly situationally dependent. For example, the benefits of adding strength isn’t as straightforward as it might appear. In situations such as chronic low back pain, changes in strength likely don’t matter.¹ Strengthening exercises for the hip and quads have been shown to help with conditions like patellofemoral pain, but actual strength changes during quad exercises may not matter as long as some form of graded exposure to load occurs², and prospectively, it doesn’t seem to matter much at all for this condition.³

Posture – another common objective – has failed to demonstrate relevance in a majority of circumstances. For example, retraining to some ideal scapular positioning is a common intervention that is not currently supported.⁴ A review of literature on the association of sagittal spine curvature and health concluded that there was no relationship between the two, and clinicians should downplay any importance.5 Even in situations where changing posture may matter, such as sitting in those with low back pain, there is no consensus on what “ideal” actual is.⁶ Finally, increased range of motion doesn’t appear to occur due to any actual change in muscle length in the majority of situations, and it also doesn’t seem to have much of a role in injury prevention.^7-9 So what does all of this mean? Just because something can be done doesn’t always mean it matters. Clinical decision making begins with choosing the adaptations that make a difference in the patient’s concordant sign and allows them to return to their desired level of participation.

Prescription of therapeutic exercise should involve clinical reasoning and be done with a clear goal in mind.

The preceding paragraph was intended to point out specific examples where the intervention wasn’t matched to the demand. In many cases, such as postoperative quad weakness, strength does play a significant role. In these situations, it’s important that the dosage is appropriate in order to elicit the adaptations needed while avoiding negative responses. This minimum effective dose was defined by Siff in Supertraining as “the condition which optimally promotes hypertrophy and strength increase [via] the production of some minimal level of force for some minimal amount of time.”¹⁰ Unless intensity (defined as a percentage of rep max) is considered, even the overly popular 3 sets of 10 is a meaningless prescription. Delorme used progressive loading in his protocol reaching a true 10 repetition maximum on the third set.¹¹ It appears that taking at least one set to failure is very important for eliciting adaptations, and this appears to hold true even with significant deviation from the commonly suggested intensity of ~65-85%.^12-14 In the rehabilitation setting, moderate load training at a lower velocity may be indicated and in these situations; taking lower loads to muscular failure seems to give most of the same benefits seen at higher loads. The paper by Wernbom et al gives an excellent review of exercise prescription that can be applied clinically.¹⁵ In many aspects, exercise prescription for increased strength and endurance is one of the most straightforward things done in the clinic. Untrained individuals respond very well to any broad range of loading parameters, and this allows for some results even with sloppy exercise prescription.

In many situations, the goal may very well not be traditional. There are many reasons to use exercise beyond the typical strength and endurance adaptations. Some examples include eccentrics for increased muscle length¹⁶, isometrics and aerobic exercise for pain modulation^17-20, loading through tissues for tissue adaptation via mechanotransduction²¹, to improve motor control, and to increase variability in the system²². Each of these approaches requires a specific, focused, and individual approach to dosage regardless of the exercise decided on.

What does all of this mean? Prescription of therapeutic exercise should involve clinical reasoning and be done with a clear goal in mind. The therapist must have a strong understanding of the principals behind eliciting the adaptations desired and these must be individualized and progressed appropriately. Every physiological and biological response is due to a stressor of some kind. The precise application of load, both mechanical and metabolic, is the key to achieving the established goals.

Originally published on Medbridge on Aug 26, 2014 – Link to original article here.

References:

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