Written by Philip Van Dyke, PT, DPT, CSCS

As physical therapists, our “thing” is that we are experts in human movement. Therapeutic exercise is a major component of our plans of care with all patients. We are educated to cater that exercise to address the specific impairments, activity limitations, and participation restrictions - I think most physical therapists are pretty good at this. But, where it seems many physical therapists and physical therapy schools may fall short is in determining appropriate exercise dosage for each patient. Coincidentally, this is a strength (no pun intended) of the Certified Strength and Conditioning Specialist certification through the National Strength and Conditioning (NSCA).

Resistance training parameters are extensively researched in the healthy population as it relates to strength and conditioning and performance. They are much less frequently studied in the rehabilitation realm. In the healthy population, there are clear parameters for load and volume established for resistance training based on the goal of the individual (power, strength, hypertrophy, or muscular endurance). The American College of Sports Medicine’s (ACSM) 2009 position stand on Progression Models in Resistance Training in Healthy Adults synthesizes a multitude of evidence to provide recommendations for both novice and trained healthy adults. There are also many other variables to consider in program construction, such as rest time, mode, frequency, and specificity, which are also well established and can be found in the ACSM's position stand paper. For physical therapy patients, these same variables come into play with the added complexity of their respective pathologies or injuries.

Goal of training	American College of Sports Medicine	National Strength and Conditioning Association
Power	1-3 sets of 3-6 reps (30-60% of 1RM for upper body, 0-60% of 1RM for lower body); Progressed to 3-6 sets of 1-6 sets of 1-6 reps with incorporation of 85-100% of 1RM for increased force production	1-2 reps at 80-90% of 1RM when goal is single effort; 3-5 reps at 75-85% or 1RM
Strength	1-3 sets of 8-12 reps (60-70% of 1RM) for novices; Progressed to 80-100% of 1 RM for more experienced lifters	6 or fewer reps at 85% or greater of 1RM
Hypertrophy	1-3 sets of 8-12 reps (70-85% of 1RM) for novice to intermediate lifters; 3-6 sets of 1-12 reps with majority of training at 6-12 reps (70-100% of 1RM)	6-12 reps at 67-85% of 1RM
Muscular Endurance	10-15 reps at "relatively light loads" for novice lifters; 10-25 reps at various loads for more experience lifters	12+ reps at 67% or less of 1RM
		*NSCA states that 1 set of each exercise may be sufficient for novice lifters but should be progressed to multiple sets per exercise

Periodization of resistance training programs is also more commonly studied in the healthy population than in those who are currently rehabilitating. With that being said, there is still no clear conclusion as to the optimal type of periodization. However, current evidence does seem to demonstrate that resistance training with some form of periodization is more effective than resistance training with no periodization. The use of periodization was initially in response to Seyle’s General Adaptation Syndrome theory, which is the idea that the body will respond to stressors by adapting to accommodate them. This occurs in three stages: alarm reaction, resistance, and exhaustion. The goal of periodization is to maximize improvements and compensation to the stressors while avoiding exhaustion. The two primary types of periodization are linear and nonlinear/undulating.

In linear periodization, load and volume are consistent throughout a longer period (weeks to months) before transitioning to different training parameters

In nonlinear periodization, load and volume are varied daily to weekly

In the rehabilitation setting, the four phases of rehabilitation that we learn about in school are somewhat similar to the mesocyles that make up a linear periodization program. However, with the limited amount of visits allotted for physical therapy, nonlinear periodization may be better suited for our setting. Regardless of the way that you choose to structure your program, exercises can still be intentionally planned with parameters that match your goals for that particular patient.

Unfortunately, there are little to no research articles that translates strength and conditioning programming to rehabilitation, and there are many other factors to consider for a patient than in a healthy, non-injured individual, such as time needed for tissue healing to take place and decreases in active range of motion. But, we can still have a goal in mind and a specific reason for selecting the training parameters that we choose to employ. So, I encourage you to think twice before automatically resorting to three sets of ten for every exercise that you prescribe to your patients. Maybe three sets of ten is the appropriate dosage, but at least have a reason for choosing the volume and make sure the patient is working with the corresponding intensity. There is also something to be said for the fact that we’re getting patients moving at all, and improvements can be made in many patients regardless of how many reps or sets you assign. If we are, however, going to claim to be experts in human movement, let’s try to make sure we bring about the greatest improvements possible in the shortest amount of time.

References:

Integrating Strength and Conditioning Principles in Physical Therapy