I mentioned in my last article that the type of training used for an injured tendon is different than that used for muscle or cartilage or other biologic tissues. And, I proposed that to accept my argument, you have to accept the premise that 1.) tendons respond both positively and negatively to physical stress 2.) that the stress required for healing is different than that required for muscle 3.) that you can actually do it.
Well, we know tendons respond to stress because you can injure them. Too much physical stress can create injuries ranging from very mild strains to complete ruptures. But, what happens when you reduce physical stress as in the case of immobilization or inactivity?
There are a number of studies that demonstrate the negative effect of inactivity on tendon although tendon weakens more slowly than its' associated muscle. The density and size of the collagen fibers decrease as does the tensile property. In the case of inactivity, such as cessation of exercise, the weakening process goes undetected. This is one reason why people, after living a sedentary lifestyle for a number of years, injure themselves and develop tendonopathies. The tendon is weak yet not symptomatic. The mind still remembers what it was like to run five miles or play basketball or tennis. Without a gradual strengthening of the body, the tendon is at risk of injury so in the excitement of getting back to a sport or activity they love, the sudden increase in force injures the tendon.
But, tendons do respond to physical stress positively. Exercise, low load training in particular, increases the cross-linkage of collagen fibers and improves the elasticity. The question is, how do you do it?
This is where having the right tools becomes important and understanding the Load Tolerance for the involved structures. Lets take the case of a patellar tendonopathy. Let's assume the client's knee hurts climbing stairs or squatting so much that it is interfering with daily activity. And, let's assume that this person is otherwise healthy, age 44, male.
The first thing I want to know is, how much load is too much? I would perform a Single Leg Squat Load Tolerance Test using a Total Gym to find out the pain threshold for squatting. A Load Tolerance Test is a psycho-physical test; the client must relay to you how he feels. This is an inherent weakness of the test and can result in either under or overstating the Load Tolerance. But, as with many tests, the protocol you use helps reduce the chance of this occurring.
I use a Total Gym because the load is a percentage of the client's body weight and it's easy to administer. Here's how I do it:
- I explain the test and what I'm trying to find out. “Today I will be performing a single leg squat load tolerance test. This test will tell me the amount of weight you can squat without symptoms or a breakdown in form. Please tell me if your knee hurts at anytime during the test. I will ask you periodically. Please answer yes or no.”
- Place the Total Gym at Level 5 (on a 10 rung machine). It is usually safe to start the test at 25% of the client's body weight.
- Push the sliding platform up and hold it so the client can get on.
- Ask the client to lie down on the sliding board and place both feet on the platform, near the top, about shoulder width apart. The client's legs should be straight.
- The client now performs a bilateral squat to about 90 degrees of knee flexion. This is to introduce the idea of how to perform the squat and to be sure the load level will not be too great.
- The client now performs five squats. Ask, "Did your knee hurt?" The answer should be quick and clear. Pain is all or none. Like a light switch. You may have a little but you either hurt or you don't. This is the step where a lot of mistakes can be made. A client who says, "Uhhh...well...not really...no I guess not...it's not that bad...." hurts. Get a clear answer. Don't be shy about re-stating the purpose. If something hurts, lower the level of the Total Gym until the movement is pain-free (and I can talk about what to do in the case of that not happening in a later article).
- Now that the client has performed five bilateral squats without pain and with good form, proceed to testing the uninvolved side. Repeat the instructions. The purpose in this phase of the test is for the client to know, to experience, "normal".
- Next, repeat the procedure with the involved limb. Five repetitions. Watch for deviation of the limb into adduction or the pelvis hiking or rotating. If that happens, even if the client does not hurt, you have reached Load Tolerance by a failure in form. If the five repetitions is not painful, increase the angle of the Total Gym one level and repeat. Give the client at least 30 seconds of rest. If the test is painful, at any point, lower the Total Gym one level and repeat.
- At some point in this process you will find either the Load Tolerance produced by pain or form failure or both. For example, let's assume that your test ends at level 7 on the Total Gym because the client's knee hurt. This means that Level 6 is the highest degree of force tolerated. You now know exactly how much force the injured limb can withstand.
From a client's perspective, this information is very helpful. Up to this point, all the client knows is that whenever he squats down for something like the newspaper or tries to climb a flight of stairs, his knee hurts. By identifying the Load Tolerance, you have tapped into something known as the Hope Theory. The Hope Theory states that hope is created by a clear goal and a map to get there. A Load Tolerance test gives you the most important part of the map: where to start.
Now that you have the data, what do you do with it?
That's coming up next.
DK
Kvist, M. (1994). "Achilles tendon injuries in athletes." Sports Med 18(3): 173-201.
Heinemeier, K., H. Langberg, et al. (2003). "Role of TGF-beta1 in relation to exercise-induced type I collagen synthesis in human tendinous tissue." J Appl Physiol 95(6): 2390-7
Kubo, K., H. Kanehisa, et al. (2003). "Effect of low-load resistance training on the tendon properties in middle-aged and elderly women." Acta Physiol Scand 178(1): 25-32.
