Resistance training is a critical piece of the rehabilitation puzzle and an area that all physical therapists should consider themselves a master in. Is this really the case though? Unfortunately, many would say “no”! So the question becomes: are these individuals who question the PT's knowledge base justified in their opinions or are they way off base?
In my experience, I would say that PTs are definitely experts in exercise intervention as it relates to pathology. Physical therapists are able to objectively measure musculoskeletal impairments and use biomechanical knowledge to select the most appropriate exercise interventions to address a specific problem. However, I would also say that even though PTs are able to choose the correct exercises very effectively, we often drop the ball when it comes to program design.
Before diving into the specifics of program design, we must first review bioenergetic systems and discuss which systems are most active during resistance training. Bioenergetic systems are divided into aerobic and anaerobic types depending on whether or not they use oxygen to synthesize ATP and include the phosphagen system, glycolysis and oxidative metabolism. Resistance training primarily involves the use of anaerobic metabolism (phosphagen and glycolysis), which means that program design must consider the nature of these two systems. The following table is very helpful in seeing how each system relates to exercise:
|
% of max. power
|
Primary system stressed
|
Typical exercise time
|
Range of work-to-rest period ratios
|
|
90-100
|
Phosphagen
|
5-10 seconds
|
1:12 to 1:20
|
|
75-90
|
Fast glycolysis
|
15-30 seconds
|
1:3 to 1:5
|
|
30-75
|
Fast glycolysis & oxidative
|
1-3 minutes
|
1:3 to 1:4
|
|
20-30
|
Oxidative
|
>3 minutes
|
1:1 to 1:3
|
Essentials of Strength Training and Conditioning, 2008
Because strength training typically involves a very high percentage of maximum power, one can see from this table how the phosphagen and fast glycolytic systems are of primary concern.
Now that we have reviewed bioenergetic systems as they relate to resistance training, we can now look more closely at the specifics of program design. In my experience within the rehabilitation setting, most therapists seem to implement resistance-training programs that include 2-3 sets of 10 repetitions for most patients. This type of program works perfectly for many patients, but depending on the stage of recovery and level of function the patient is hoping to return to, this program may need to be modified in order to maximize performance. The following table shows the four types of resistance-training programs depending on the goal(s) of the program.
|
Training goal
|
Load (% 1RM)
|
Goal Repetitions
|
Sets
|
Rest period length
|
|
Strength
|
³ 85
|
£ 6
|
2-6
|
2-5 minutes
|
|
Power
*single-effort event
*multiple-effort event
|
80-90
75-85
|
1-2
3-5
|
3-5
3-5
|
2-5 minutes
|
|
Hypertrophy
|
67-85
|
6-12
|
3-6
|
30 seconds – 1.5 minutes
|
|
Muscular endurance
|
³ 67
|
³ 12
|
2-3
|
£ 30 seconds
|
Essentials of Strength Training and Conditioning, 2008
As I stated, most therapists use a program that includes 2-3 sets of 10 repetitions. Such a program may work well in the early stages of recovery, but does not really match any of the referenced programs. This is why I argue that the practitioner needs to remember that as the patient heals, the resistance-training program will need to be modified in order to optimize performance. Following these guidelines will ensure that the physical therapist is designing resistance-training programs that are based in current strength and conditioning research.