Muscle Sport Magazine

The Physics of Weight Lifting, Part 1: Gravity

By Paul Becker, copyright ©  Paul Becker – This is the first of a series of articles that will look to the science of physics to help us make our training more effective. In this article we will look at the simple law of gravity and how this effects lifting weights.

Gravity is defined as – The natural force that causes objects to be pulled towards the center of the earth, it causes objects to have weight.

Because the earth is round, no matter where you are on it the center is always straight down. Thus, in order to have continuous tension on our muscles while training we must make sure the actual resistance we use travels a path that is straight up and straight down. an example of this is the military press, the weight is pushed against the force of gravity in a straight line up until the arms are locked over your head, then it is lowered slowly resisting gravity, in a straight line to about shoulder level.

In all of the big basic exercises (deadlifts, squats, bench press, military press, rows, etc.) the bar always travels straight up and straight down, this keeps the muscles being worked under a constant load. The basic exercises produce the best results because they stimulate growth in more then one muscle at a time, but we also now know that they provide continuous tension in the muscles involved – this is the secondary reason why they are so productive.

Testo 468 x 49

There are a group of exercises called isolation exercises these tend to work only one muscle or muscle group at a time, these exercises are not very efficient at producing overall body mass as the basic exercises. The reason for this is they don’t stimulate growth in many muscles at once, but also secondarily because most of them don’t provide continuous loading of the muscles.

In most isolation exercises the bar travels in arcs where only the middle of the movement approximates a pull against gravity. Take the barbell curl for example, The bar is lifted from the upper thighs in a circular path towards the chin, at the beginning of the movement the bar is traveling more horizontally then vertically, it is only when the bar is in the middle position that you are pulling it upwards against gravity, then as you move into the top position of the movement you are once again moving the bar in an almost completely horizontal direction. This is why curls tend to be easy at the beginning, hard in the middle and the easy again at the end.

Other examples of this type of exercise are, lateral raises, flys, tricep extensions, pullovers, etc.. Any exercise preformed with a barbell in which the resistance doesn’t travel straight up and down, will cause a loss of continuous load on your muscles. As a side note, preacher curls done with a barbell are even less effective because it make almost the whole movement horizontal, the only benefit is the elimination of cheating by benefit the upper arms from moving.

Ok, so how do we use this data to make our training more productive? We make sure that we have continuous tension on our working muscles by making sure that the resistance we are using is traveling straight up and down. There are many machines that use pulleys to lift a weight stack up and down against gravity even though you may be moving in a circular motion, if you workout in a gym where these are available – make use of them.

But even if you train in a home gym you can still use these principles to build more muscle. Let’s take bicep work for example, do some close grip pull-ups with the palms toward your face, this strongly works the biceps and the resistance (your own body and any extra weight you add) is moving straight up and down, it also give you the added benefit of peak contraction at the top of movement. Or instead of regular barbell curls try body drag curls, take a shoulder-width grip and start from the regular curl position drag the barbell against your body up to your throat while keeping your elbows back.

For your triceps, nothing beats dips with extra weight added by mean of a belt you can hang plates on to. For deltoids, notice that the shoulder joints do the exact same motion when doing military presses as doing lateral raises, so you don’t even need to really do the lat. raises it’s just more of the same.

You may ask “But what if i want to do some pre-exhaustion, I would have to do some lateral raises then, wouldn’t I?”. No, you don’t Try this instead – do a set of upright rows immediately followed by a set of military presses. It works this way, the upright rows fatigue the biceps and shoulders but leave the triceps fresh, now on the presses the strong triceps push the already fatigued shoulders even harder really making them grow. This is what I call the pull/push method of pre-exhaust, it can also be used for other muscles of the torso.

JCS - GBA 468x60

In conclusion, there are many ways to make gravity work for you in weight training, now that you know the theory of this article you may come up with some new and interesting exercises or exercise combinations.

About The Author: Paul Becker is a natural (steroid free for life) bodybuilder and fitness consultant. For more information on Bodybuilding and Bodybuilding Supplements visit his website at

Photo by Francesco Pillari

Leave a Reply

Your email address will not be published. Required fields are marked *