Strong Muscles, Strong Tendons: Why Holding Counts
If you’re a client of ours, I’m willing to guess that many of you have been exposed to the new isometric exercises we’ve been programming. An isometric exercise is any exercise that requires you to hold a position under load for an amount of time. Let me start by saying that they are very important and, with the support of new evidence, will do my best to explain why.
Isometric drills are important for tendon health.
A Tendon (not to be confused with a Ligament) attaches muscle to bone. Please reference the image to better understand the difference between tendons and ligaments.
I’ve been listening to talks from Dr. Keith Baar at UC Davis recently and he has been enlightening me on this topic. He’s been preaching that tendons, like other structures in our bodies, are not homogenous. They have varying degrees of stability and strength throughout different parts of the tendon. So, if we only load a muscle quickly through a range of motion, the strongest parts of that muscle and tendon will bear the load. However, if we submit that muscle and tendon to an isometric hold, the strong parts will tire out and eventually target the weak parts, allowing them to strengthen too.
When the weak spots go unworked and overlooked, it is known as stress shielding. An external example of stress shielding is a cast or a boot. When a muscle is exposed to stress shielding long term, like with a cast, the muscle atrophies (shrinks) and becomes weaker because it is no longer exposed to load. For this same reason, physical therapists have begun to adapt their practices. Gone are the days of prolonged bed rest and immobilization following an injury or surgery. Perhaps you’ve known someone who has gotten a knee replacement, chances are the doctors had them walking that same day!
Movement is medicine.
So, what does all this mean? It means that appropriately loading muscles and tendons can be a great way to sustain their health.
I know doing these exercises, which can help to prevent injury, can be a hard sell; no one measures their life outcomes in non-events, or things that didn’t happen. However, stories seem to have an impact. I’m willing to bet that you know who Aaron Rodgers is, for those uninitiated, he plays football in the NFL. Remember when he tore his calcaneal (Achilles) tendon?
A likely explanation for why this happened is that he had weak points in that tendon. Despite boasting a 400-pound squat, the strong points of his tendon were probably shielding the weaker points. Then, when those weaker points got exposed, snap! Granted, there are some other variables to consider, they were playing on a turf field, which seems to increase the likelihood of these sorts of non-contact injuries, and we’ll never know exactly what his training routine consisted of, but my hunch is a weak spot in the tendon. Afterall, if we make a muscle strong and never stop to consider the tendon, that tendon may not be able to support the force the muscle can now produce.
In short, isometric exercises aren’t sexy, they’ll be harder to brag about, but they can save you from having a devastating injury like Aaron did.