Here are two common questions: “Those guys are twice the size of us, but they struggle with weights that I can do. What is that?” And the other would be, “How come you don’t have me do that machine” or “How come you don’t have me do that exercise?” I’ll address the latter questions as they pertain to why we don’t do isolation exercises.
Unless you are into bodybuilding or undergoing physical rehabilitation, performing isolation exercises should have no role in your training regimen.
The first thing I try to teach my clients is that the body does not work well in muscle isolation. Instead, it works better in movements along a kinetic chain; meaning, completing complex movements using a greater number of muscle groups. (e.g., pull-ups, dead lifts and bench press). In fact, there really is no such thing as true muscle isolation. There is almost always a nearby muscle group that will assist in some way with whatever movement you are doing. Moreover, many muscles groups actually cover two joints not just one.
When you attempt to ‘isolate’ muscles, you are actually creating a body that is non-functional and more prone to injury. Essentially, you are creating a body that is a sum of body parts, instead of a powerful, functional body that works together. The term synergy comes to mind.
It’s a cruel trick; isolate body parts to achieve the aesthetic qualities seen in magazines, yet sacrifice quality of life by suffering with joint problems, tendonitis, and possibly bulking up. Conversely, if you would rather have a lean, muscular, injury-free, functional body that works in synergy to perform complex movements (in athletics or even everyday tasks), then by all means stay away from muscle isolation exercises. Believe me, focusing on how well your body functions will give you the body that looks even better than it would have if you focused on muscle isolation.
In college, I used to do a lot of biceps curls (for the girls). I also suffered with intermittent tendonitis that would run from my biceps tendon in the front of the shoulder to my elbows, all along my forearms and even my wrists. The only remedy was to stop doing curls. When I started working in Cormax only gyms, I stopped doing isolation exercises all together. I started to train using more complex movements and noticed that my biceps were getting a better workout simply by doing cleans (well, version is more like a high pull), rows and pull-ups. And the tendonitis issues were non-existent, while my overall strength catapulted.
Another benefit to moving away from the ‘muscle isolation’ mindset to a more ‘complex movement’ mindset is that you will find it much easier to lose body fat. The reason is that by focusing more on multi-joint complex movements as opposed to single-joint muscle isolation, you not only burn a lot more calories during each workout, but you also increase your metabolic rate, and stimulate production of more fat burning and muscle building hormones.
Let’s do one more example. The leg extension machine is a single joint exercise that works mainly the quadriceps, and is commonly used by Physical Therapists to wake up the quads and stimulate them to fire (contract). Because of physics and bio mechanics involved, they never allow the resistance to go above 60 pounds. The shearing force on the knee joint becomes more harmful than helpful when heavier weights are used. So once the quads can contract smoothly, the PT moves onto closed-chain (foot on the ground) exercises. For this reason, we just walk past the leg extension machine hoping we’ll never need to use it.
Exercises like squats, jumps, lunges, and dead lifts are all multi-joint complex movements that work numerous muscles in the body (in addition to the quads). Training the body as a functional unit, creates more coordination, stability and greater strength in the long run (when done properly), and also burns far more calories, in less time, compared to the isolation exercises.