ESTIMATING YOUR CALORIE NEEDS

ROCKET SCIENCE: LAUNCHING A PAYLOAD TAKES MORE THAN ONE "G-FORCE"

Frederick C. Hatfield, Ph.D., F.I.S.S.A.
Frederick C. Hatfield II, MS, MSS
International Sports Sciences Association

"This ain't rocket science!" is a phrase uttered when chastising someone who, despite listening attentively, just can't understand what you said. We've all been party to such inane utterances. Well, maybe it's the WAY it was said, and not necessarily WHAT was said! So, this time, we’re going to change tactics. See, what we’re about to discuss IS rocket science in it's most elemental form. Launching a barbell (or whatever) off your chest (or from wherever).

Now, benching isn't difficult to understand or perform. Just lift the bar! Simple as that. Well...not really, if your intentions are to 1) lift a LOT of weight, or 2) make whatever amount of weight you're lifting do the MOST good in terms of improved muscle mass or strength!

Isaac Newton. Name ring a bell? Gravity? Laws of motion? Newton became quite famous for saying (among other things), "Force is equal to mass times acceleration." F=ma. That's what he said. So, let's apply this equation to real-life lifting. "Launching" a "payload" as it were. What amazes me is that it has rarely been given consideration by popular writers in the muscle mags. It is, after all, what serious, scientific lifting is all about.

Newton also said, "What goes up must come down." Well, fellow Iron Worshippers, we say different! For bench pressers and squatters, what comes DOWN must go UP! Here's how. To make a 500 pound weight go up, you must exert MORE than 500 pounds of force. If all you exert is 500 pounds of force against the bottom of the bar, the weight will remain on your chest. You’ve merely EQUALED the force of gravity. And, once you have the bar moving (it will ONLY do so once you've applied MORE than 500 pounds of force), you can now return to exerting 500 pounds of force (i.e., you must exert one "G," of force, or one times the force of gravity) to keep the bar moving at that same rate of speed. Elementary Newtonian physics from high school says we’re right.

This "one G-force" mentality is NOT the best way to lift! Let's have a look at the conventional way a 500 pound bench press is performed to illustrate Newtonian logic in lifting. Then we'll show you not one, but two better ways! Trace your finger on the wavy line in Figure 1A below as we explain what's happening in the caption. It’ll help you to visualize the way it usually happens in the gym.

1. Take the 500 pound bar off the rack and get ready to lower it to your chest
2. Unlock your elbows and then shut off a few motor units in your pecs, triceps and anterior delts to allow gravity to take over -- the bar is now going down
3. As you sequentially shut off more and more motor units, the bar descends more rapidly
4. You reach a point where just the right number of motor units are shut off, and the bar again weights 500 pounds and descends at a fixed rate of speed
5. You anticipate the bar hitting your chest so you reactivate a few motor units to slow the descent
6. The bar hits your chest
7. It is immediately unweighted because you're resting it on your chest
8. You push against the bar to press it upwards
9. You finally get enough motor units turned back on to equal 500 pounds -- the force of gravity
10. You have to turn on MORE muscle fibers than what it takes to generate merely 500 pounds of force in order to make the bar move upwards -- to get it off your chest
11. You accelerate the bar by turning on more and more motor units until it achieves a stable rate of speed as it moves upward
12. You anticipate the bar reaching lockout (usually beginning at around 1/2 of the way to lockout), so you turn off a few motor units to slow the ascent a bit so you don't "jam" the bar into the locked out position (this sort of ballistic force can cause injury)
13. You achieve lockout
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Insert Figure 1A Here...

Caption: Figure 1A represents the change in actual resistance produced by a 500 pound barbell during the negative and positive strokes in a bench press movement. The broken line shows the constant weight of the barbell without the acceleration forces included. The solid line shows the actual resistance applied to the hands of the lifter. The lifter experiences the forces of acceleration and inertia as well as the actual barbell weight.
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NO, NO, NO! This is NOT the best way to get a big bench or train for one, and it's NOT the way to make your muscles grow! Sure, you got the weight up! But, Mamma mia! Don't you want to get MORE up next time? The technique described above is cute. It works. But "cute" doesn't cut it in today's world of PERFORMANCE training! Newton, were he alive today, would have earned the title of "Mr. Olympia!" Or perhaps "Dr. Bench!" This form of ho-hum training is an unmitigated abomination of his genius! More importantly, man would never have gotten his first Titan rocket off the ground with such thinking.

So, let's adjust Newton's formula (F = ma) a bit. Let's add a third element to the formula. Time. See what happens.

Notice that in the example above, you're pushing with 550 pounds in order to make the 500 pound lift. Remember, to make the bar go up, you had to push with more than 500 pounds of force. Notice too that it took you nearly 3 seconds to get the bar off your chest to your maximum force output (Fmax) and another second or two to reach lockout.

This tells a lot. First, you're stronger than 500 pounds because you exerted 550 pounds of force. Second, since you have far less than two seconds worth of ATP, you were ill-advisedly operating in the CP pathway of muscle energetics in the process of achieving your lift. That means one thing. You have a few pounds left in you if you can reduce the time element. Whether you like it or not, fatigue had already started to set in after roughly 1.26 seconds into the lift.

To lift more than 500 pounds, then, you'll have to do it in less than 1.26 seconds To do that, you will have to generate far greater acceleration. If you do that, your force output will rise substantially. Watch. Trace your finger along the curve again (see Figure 2) as we take you through this in the numbered steps below:

1. Take the 520 pound bar off the rack and get ready to lower it to your chest
2. Unlock your elbows and then shut off a slightly greater number of motor units in your pecs, triceps and anterior delts to allow gravity to take over -- the bar is now going down slightly faster than in the first example
3. You anticipate the bar hitting your chest much later in the decent than in the first example, and you reactivate a large number of motor units to slow the descent more quickly
4. The bar hits your chest, and is immediately unweighted because you're resting it on your chest (as in the first example), but this time you virtually explode it off your chest by recruiting as many motor units as possible instantaneously. Stretch reflex and viscoelasticity of tissues aid greatly in this maneuver
5. Since you've recruited far more motor units than needed to move 520 pounds, you r acceleration rate is far greater, and you reach Fmax far sooner -- well within the 1.26 second window prior to fatigue setting in.
6. You anticipate the bar reaching lockout at around 2/3 of the way to lockout (instead of 1/2 the way as in the first example, thereby allowing a greater amount of time over which to accelerate the bar), so you turn off
7. many motor units to slow the ascent quickly so you don't "jam" the bar into the locked out position (this sort of ballistic force can cause injury, so before using this technique, you must prepare connective tissue through specialized training to handle such stress)
8. The bar reaches lockout
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Insert Figure 2 here........

Caption: Figure 2 represents the change in actual resistance produced by a 500 pound barbell during the negative and positive strokes in a bench press movement. The broken line shows the constant weight of the barbell without the acceleration forces included. The solid line shows the actual resistance applied to the hands of the lifter. The lifter experiences the forces of acceleration and inertia as well as the actual barbell weight. But the difference between this technique and that illustrated in Figure 1 is clearly that 1) the time element as well as the forces of inertia and acceleration are all much more acute.
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Now, over the past 15 years or so, this system of training has been called "compensatory acceleration training," because you are compensating for improving leverages throughout the lift by accelerating the bar. Why do this? Because you CAN! As leverage improves, you are able to move a given weight with greater ease. Simple. So DO it! The math is sound, and the training works.

There's one slight flaw in compensatory acceleration training, though. What to do about the blasted INERTIA! Overcoming it contributes to both fatigue during the lift as well as increasing the potential for injury (usually only among those who imprudently forget to PREPARE for the ballistic stress). There are a few ways in which you can get rid of the potentially damaging inertia. To mention a few:

1. Using a block and tackle device to lift the weight, you reduce the distance over which the resistance travels by one half, but maintain normal range of motion with your muscles. This reduces the inertia by half.
2. Make the resistance great enough such that you prevent any ballistic episodes taking place.
3. Use a flywheel, fluid cylinders or clutch plates to control the speed of movement.
4. Purposely go slow with the weight.
5. Use compressed air cylinders to functionally eliminate inertia (air doesn’t weight much).

There is only one way ever devised that can functionally eliminate inertia for you. Air pressure. Yes, air! Because of its relative weightlessness, compressed air effectively eliminates ALL of the dangerous inertial forces. Sometimes, this can be very important. Let’s discuss what happens if you "dampen" your movements with air pressure.

What does science have to say about this? As we know, the scientists -- the intrepid sleuths who prowl the ivory towers of academia -- are quick to question any theory, often looking to disprove it! Nothing wrong with that! They are only looking for truth.

Many sports scientists believe that pure limit strength is not the only important factor in developing muscle. Acceleration, velocity and speed of movement are also important factors in muscular strength training. In the world of athletics, a vast majority of movement is performed at high speed or with great acceleration. As Stone and Kroll (1978) stated:

"In most athletic activities high speed is a very important factor. The strength training for athletics should therefore be performed at high speed if the skill is performed at high speed. The slow speed strength developed by resistance training is primarily transferable to athletic movement only at the slower speed at which it was developed."

Now, not everyone desires to be an athlete competing at high levels of competition! Perhaps you simply want a bigger chest. Maybe you just want to bench press more. Or maybe, you simply want to get into shape! So your question may be, "Will this compensatory acceleration help me achieve my goals?" In a word, yes.

An experiment comparing gains of seventeen bodybuilders who performed conventional bench presses with a second group of seventeen bodybuilders who performed what the scientists called a "bench throw" movement. The bench throw is interesting. The scientists rigged a bench press rack so that the bar could be thrown upward -- out of their hands -- and caught by a safety mechanism so it wouldn’t come crashing down on them. Using all the special equipment scientists have in their labs, the scientists measure several factors, including average and peak concentric velocity (the speed at which the bar traveled), peak power, and average concentric force and power. Here’s what they found:

Average concentric velocity -- the throw movement was 27% higher in average concentric velocity than the conventional bench. In other words, the thrown bar reached a higher average speed.

Peak concentric velocity -- the throw movement was 36% higher in overall speed of the movement than the conventional bench. In other words, the peak speed of the bar was faster.

Average concentric force -- the throw movement was 35% higher than the conventional bench for overall force. Since force equals mass times acceleration, and mass stayed the same but accelerated at a much greater velocity, the force moving it must have been greater.

Average power output -- the throw movement provided an amazing 70% more power than the conventional bench. The peak power for the throw movement was 67% higher! Remember, Power equals force times distance per unit of time (P = fd / t).

So, in order to achieve this speed, the muscle fibers must be turned on and LEFT on for a longer period of time. The scientists provided EMG readings (which monitor muscle activity), and the muscles were indeed active for longer periods of time. When each lifter was about 3/4 finished with the conventional bench press, muscle activity dropped considerably (due to the involuntary anticipatory response of reaching the terminal position of lockout), whereas in the throw movement, muscle activity remained almost at a constant rate through the entire movement.

Ask yourself, "Do I want to have total muscle involvement through three quarters of the lift, or do I want total muscle involvement through the ENTIRE movement?" An easy question, if you really want to get the most out of your workout!

Even though the scientists of this study didn’t use pressurized air, they did the next best thing: they eliminated the inertia! They allowed their subjects to forget about having to stop the mass (the barbell) at lockout! Does this happen when using pressurize air? Of course it does, because their is very little inertia to begin with!

Is air training safe? Well, can you move a barbell with as much force as possible and still avoid injuries? Most sports scientists would say, "No you can’t!" But the blame is often put on the resistance instead of the speed with which the resistance is moved. in his original research report in the NSCA Journal (198......), after launching his line of pressurized air training equipment, Dennis Keiser stated:

"...everyone read that fast speed of movement during an exercise jerked the muscles violently and produced nothing but injuries. This statement is true in that injuries were produced, but the blame was put on the wrong element. Speed appeared to be the cause only because the proper equipment had not been developed...."

Keiser is referring to the notion that equipment using mass and inertia had been used. With pressurized air is used as resistance, the resistance, of course, remains. However, mass and inertia are functionally eliminated. Voila! No injuries!

Trace your finger along the curve again (see Figure 3) as we take you through this in the numbered steps below.

1. With the handles in your hands, load air into the cylinder until it reaches the desired level of resistance.
2. Lower the handles toward your chest
3. Make the transition from down to upward movement
4. Push as hard as you can every inch of the way up
5. You achieve lockout
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Insert Figure 3 Here.....

Caption: The broken line represents the desired strength curve. The solid line represents the resistance output of the low inertia variable resistance machine. The slight deviations from the desired curve at the beginning and end of the positive and negative strokes will occur only at very high speeds due to the slight inertia produced by the small weight of the handles in the lifter’s hands. There is a major difference between what’s happening here as opposed to what happens using a barbell as illustrated in Figures 1 and 2. Here, the resistance is maximized throughout both the negative and positive strokes, accomodating for variances in your leverage. There is almost no acclerative or inertial forces to contend with, but more beneficial resistance throughout.
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Now, the bench press machine used in the study mentioned earlier is not exactly common in the gym. In fact, none exist outside the laboratory! Furthermore, this is just one piece of equipment! What about leg training? Upper back training as well as training your arms? If you are going to use compensatory acceleration in your lifting, you might as well do it for all the muscles you want to train, no? Certainly for all of the movements involving relatively long ranges of movement. And the simple answer is to use pressurized air because the technology already exists!

In doing so, you will not be concerned with mass, acceleration or inertia. Injuries are not a factor. You will be able to work your muscles maximally through the entire range of motion, thereby increasing the effective overload and (as a result) the muscles’ growth in strength and size. Psychologically speaking, if you know that danger no longer exists while moving as fast and as explosively as possible, you’ll put forth more voluntary effort! The bottom line is that you will safely get more out of each rep, each set, each exercise and each workout, with an attendant boost in sports performance ability!