Any bodybuilder wannabe worth his/her salt would have at one time or another referred to “isolating a muscle for peak gains”. What I want to discuss is how this notion of muscular isolation is a little silly. You see, no matter how hard you try you can’t truly isolate a muscle. Even if you try to remove all other joint activity (i.e. a preacher bench curl) you’ll never get just one muscle to work independent of all others, the body simply doesn’t work that way.
Imagine your muscles working as a highly trained philharmonic orchestra playing a symphony. There might be times in the performance were the conductor (you) want to bias or bring up certain instruments in volume (muscular focus) and make others take a back seat by reducing their loudness. This dynamic contrast is kind of how your body works. While you can bias and get a particular muscle group to work a little harder by mechanically increasing the load on a particular joint that same muscle group doesn’t actually work strictly on its own. All the other muscles in the area (and some no where near it!) work to provide a platform from which your target muscle group can contract against (like an instrumental solo in an orchestral piece). Further as the position of the joint in question (remember muscles function to move joints and their associated bones) changes so does the neural hand-off of the muscular bias from one to another. In other words, one muscle changes roles and passes off the bulk of the activation stimulus towards force opposition for a slightly different role (i.e. joint management or plane maintenance) and so on down the line as the movement is completed and repeated.
Sufficed to say, aside from the complexities of the above explanation, muscular isolation while nice in thought is more myth than reality (kinda like the male ‘G’ spot!). Our muscles all work in a highly orchestrated and organized manner to make any and all movement possible.
Still need more proof? Ok, try doing a standing barbell curl while I come over and take a scalpel to your Achilles tendon. Assuming you get past the shock and initial pain you’ll be hard pressed to generate enough tension in your body for your elbow flexors (the muscles that bend your elbow) to contract against! See, no isolation!
Ok, so what does this mean? It means you need to be very aware of what’s going on inside your body at all times. Just because you’re moving a weight doesn’t mean you’re accomplishing what you think you might be or what the ‘program’ says. Again, I encourage you to be aware of your body, really feel what is going on and think about the movements you are performing. I’ve said it before and I’ll say it again, weight training is so much more than just moving weights around. It’s about proper and effective activation of muscles through the appreciation of structural anatomy. Sure, many people get some benefit from throwing weights around in the gym with little if any regard for the things I’ve been discussing in the last couple of articles, but man, just think how much more you can accomplish when you consider all the factors! Imagine how many years of safe, injury-free lifting you can benefit from when you respect the structure of the body and the way physical forces affect it. It brings a tear to my eye I tell ya!
So I encourage you again, think, use your head, READ and ask lots and lots of questions. Train smart, train hard, and train safe.