The Architecture of Exercise: Form Follows Function
Efficient bodybuilding comes from knowledge, experience and proper form.
For the past two months we've been looking at the Big Picture-the general bodybuilding principles that can make anyone's training more effective. For example, we talked
about ideal exercise form being dictated (inexorably!) by basic biomechanics, not personal preference.
We also figured out the best way to do a close-grip pulldown. We separated the details of close-grip pulldown performance into a series of "this way or that way" decisions
(such as whether to lean forward or backward during the exercise), then compared the effect of each to our goal: achieving maximum tension in the target muscle with
minimum stress on associated joints. The result, when you put all the decisions together, was a transformed close-grip pulldown - a supercharged movement that ekes every
last ounce of mass-building potential out of the effort you put in.
Well, I got a bunch of letters about that column. Basically, they all said the same thing. The close-grip pulldown example was "neat" (guess my readers aren't worried about
Madonna getting hold of their letters), but just what were those wonderful, all-powerful, general principles to use in optimizing form? I'm going to take a stab at answering
that this month.
What Value, Perfection?
For starters, make no mistake: Good form does make a difference! Sure, you see some pretty big folks using some pretty lousy form in the gym. Those are usually the same folks who are convinced that a workout has to be at least three hours long to be effective and whose joints eventually decide to take an extended or permanent holiday.The truth is that almost any training, whether the form is good or bad, produces some results, but training with good form generally produces faster results, and it keeps your joints from one day deciding that a 15-pound incline-bench press is a fine upper limit, thank you very much!
Mechanically speaking, the goal of optimizing form is twofold: to maximize appropriate tension in the target muscle throughout the range of motion, and to minimize joint stress.
Line 'em Up!
Achieving both objectives starts with making sure an exercise does indeed target the muscle you want to work. Many don't. The common situp, for example, which is supposedly an abdominal exercise, is motivated primarily by the psoas muscles, not the abs. Likewise, hanging leg raises done the way most athletes do them-with the back flat and all the movement occurring at the hips-is also a psoas exercise, not an ab exercise. The list goes on and on.For an exercise to effectively target a particular muscle, the target muscle must be primarily responsible for the exercise movement-not just involved, not just stabilizing, not just responsible during part of the range of motion, but primarily responsible. If an exercise doesn't do that and can't be modified to do it, the exercise should be thrown out.
Technically, a movement effectively targets a muscle when it pits the muscle's line of pull against the weight's direction of resistance and maintains that relationship throughout the range of motion.
Take the free-weight biceps curl, for example. The biceps' line of pull aligns with the action of the elbow joint. (Good thing, otherwise bending the elbow would be darned uncomfortable!) The direction of resistance for any free-weight movement is always straight down. So the only position that places the biceps' line of pull in opposition to the direction of resistance is one in which your el-bows face straight down and you curl the weight straight up.
If there's any diagonal movement at all-that is, if your elbows drift out to the sides as you curl-you are actually trying to move the weight side-ways, not up. There are two problems with this. First, you decrease the effectiveness of the exercise; whatever energy is going into trying to move the weight sideways is totally wasted in terms of building mass. Second, any such misalignment puts a torque on associated joints-in this case, the elbows. A torque is a rotational force that acts against the way the joint bends. Martial artists know that the easiest way to injure or break a joint is to apply a torque to it. Enough said?
If you did nothing but modify every exercise you do so that force and resistance were aligned properly throughout the range of motion, chances are you would dramatically increase the effectiveness of your workout and decrease your risk of joint injury.
Keep 'em Wide!
Okay, on to the second important step in maximizing tension in a target muscle-moving against resistance through the widest arc possible for the muscle's associated joint. Now, it might at first seem impossible to do anything else, as your joints bend where they bend, and you certainly can't shorten the length of your arm, leg or whatever. Surprisingly, in effect, you can!Back to our curl example. When you do a curl, you maximize the arc of travel if your elbows stay even with your sides as you lift the weight. If your elbows move backward (a very common error), it's as if you are actually pivoting from a point halfway down your forearms.
Try it. Do a normal curl. Now do one in which you let your elbows drift back while you lift. Feel the difference? From a biomechanical perspective, when your elbows drift back, you are approximately halving the arc of travel and, consequently, decreasing the work being done by your biceps. Letting your elbows drift back severely compromises the effectiveness of the curl.
You can make the same argument against letting the elbows drift back during triceps pushdowns or against dropping your torso to the bar during bent-over rows instead of maintaining torso position and bringing the bar up to it. Again, both decrease the arc of travel against resistance, rendering the exercises less effective. Keep those arcs full!
Throw 'em a Curve!
Here's our final principle for maximizing target muscle tension. We talked before about properly aligning force and resistance. Well, it's also important to match force curve to resistance curve.The force you can bring to bear against resistance varies throughout each joint's range of motion because of the way muscles and joints interact. When flexing the elbow, for example, you are weakest when the elbow angle is 40 degrees and strongest when it's about 120 degrees.
Let's say that the maximum amount of force you could generate at that 120 degree point is enough to lift 70 pounds. If you were forced to do a curl against a fixed load of 70 pounds, you couldn't move the bar-because at any angle other than 120 degrees you wouldn't have the "strength."
"But aren't I doing a curl against a fixed load every time I lift a barbell?" you ask. "Obviously the barbell's weight isn't changing while I lift it."
Yes and no. The weight of the barbell remains the same throughout the lift, but the resistance you experience during the lift does, in fact, change. At the bottom you are pushing forward, and the weight is pulling down. You aren't working against any resistance to speak of. The same is true at the top. You are pulling the weight toward you; it's pulling down. Again, you aren't working against any resistance to speak of. Only at the 90 degree point when you are pushing straight up against the bar and it's pulling straight down, do you experience its full weight.
So just as the force a given muscle/joint system can bring to bear against resistance changes at different angles, so does the resistance imposed by the weight. The idea is to get these two to match as closely as possible.
One way to do that would be to make graphs of the force curves for each joint and then build machines with matching resistance curves.
That's what Nautilus tried to do with its eccentric cam line, and according to available research, some of its machines weren't particularly successful at this.
There's a simpler and more effective way. Force and resistance curves are most closely matched when resistance feels constant to you during a lift. You'd be surprised how often you can experiment a bit, then modify exercise form to make that goal.
Here are a couple of examples: Using a preacher bench and cable curl machine, you can put the tension peak during the curl right at 120 degrees. Stepping back from the pushdown machine so that the cable approaches you at an angle, then leaning into it during a triceps pushdown does a darn good job matching force and resistance. Getting a partner and doing forced reps does a pretty good job too. [Note: If you don't want to do the experimenting to match force and resistance curves yourself, get Jerry's book, Secrets of Advanced Bodybuilders, which shows the modifications to many common bodybuilding exercises.]
When you've modified an exercise so the force curve closely matches the resistance curve, you've gone a long way toward ensuring maximum tension in the target muscle throughout range of motion.