Commander's Fit Tip: Newton Rocks AEDC

  • Published
  • By Col. Michael Panarisi
In last week's "Need for Speed" we uncovered the secrets of interval training, specifically how you need short recovery periods between intense bursts to let the batteries recharge for the next blast. The science behind this technique is very solid, but increased aerobic efficiency and improved tuning of your "fast twitch" muscle fibers will only take you so far.

If we're serious about going faster, we have to look at the fundamental mechanics of motion, and for that, Newton is our guy. Most of us remember "Newt" for his dealings with apples and explanation of gravity, but from that simple observation we have three foundational aspects of motion that directly correspond to our exercise regimens. Although Newton never claimed to be an exercise physiologist, his "laws of motion" offer us a useful guide for planning our workouts. And since running is all about motion, these three laws are particularly useful.

You don't need to be a real engineer (spelled m-e-c-h-a-n-i-c-a-l engineer!) to understand these principles, but just so we can get the EEs and AEs all on the same page let's review...

1. Objects in motion will to stay in motion unless acted upon by an external force

2. Acceleration is proportional to mass and the force applied (the infamous F=ma)

3. For every action there is an equal and opposite reaction

Ignoring these principles will leave our workouts incomplete. Let's look at each one and what they contribute to solving the running problem.

Objects in motion...

It strikes me that Newton wasn't watching a track and field event when he came up with this one. If he was, he would have observed that "Runners in motion tend to cease motion and collapse for no apparent reason." So did Newton get this wrong? Not really. It's the second part of the law that's in control here, namely the "external force." This is easier to understand if you're running against a headwind. That annoyance in your face is the external force, so while you are running, you're constantly overcoming this and other external forces.

But there's one element of this law that's easily overlooked. All this talk about forces and motion needs a unifying element, and that element is the direction that the forces are applied. If we really want to sound sophisticated, we can recall that forces and motion are best represented by vectors, and vectors have both magnitude and direction. It's the directional component that makes the analysis interesting. Running is essentially a two dimensional event, so we can simplify the forces and motions into two groups--up/down, forward/back.

Since we're really only concerned about moving forward while we are running, we need to maximize the forces acting for us in the forward direction, and at the same time, minimize the amount of time we spend (waste!) moving up and down. If you completed a vector diagram of yourself running, you'd notice that gravity really isn't the culprit, it's actually drag along your forward line of motion. You see, gravity is always working against us, but its force is in the vertical direction. Every inch we move up and down represents a force we have to generate to combat gravity, and none of that force is actually moving us forward any faster.

Just like Newton, this phenomenon is easy for us to observe. Just watch any track and field event, and you'll notice the pro's heads are not yo-yoing up and down as they go around the track. If yours does, correcting that will take a focused effort to fix your mechanics, and for that we'll need a trained professional. I'm working on it! More to follow on that.


The second law is the real money maker. It's well understood by physiologists that running is not a strength building event. It's great to increase or endurance and aerobic capacity, and of course running is a great way to improve your running, but ignoring Newton's second wall will put us in a "plateau" relatively quickly. Our natural response would be to just do more running, but if we're plateaued, we need to do just the opposite. F=ma explains why.

Let's assume that while we are running, our mass remains constant. From Newton's first law, we understand the forces and acceleration are directional, so let's focus on the forward direction. Since we don't have wheels at the end of our legs, every step generates an acceleration and deceleration in the forward direction. So, according to Newton, the only way we can go faster is to have a bigger "F" in the forward direction. That "F" is a result of our leg strength, making leg strengthening a crucial component of our workout, and for runners, probably the most overlooked.

OK, so you're convinced, and headed to the gym right? Great, but the leg workout you need may not be what you think. We tend to focus on our biggest muscles in the gym, and the easiest to work on are the quadriceps (those big ones in the front of your thighs). Squats, leg presses, leg extensions...all WRONG!!

While necessary for running, few runners have a quad deficit. Why? Try this. Stand with your feet shoulder width apart, and bend at the knees to move up and down vertically. You feel this in your quads, right? So your quads are for moving up and down. If you did this trick 100 times, how far forward would you move? That's right, nada. Gotta have quads to stay vertical, but to move forward, they don't get into the fight.

Next trick. Put a quarter on the ground about 12 inches in front of your foot (Newton doesn't care which one). Step on the coin with the ball of your foot, and drag it back behind you. What muscles did the work? If you felt calves, glutes and hamstrings, you're getting the picture.

Now it's just about impossible to work glutes without working quads too, but focus on the glutes for this effort. Lunges, toe raises, "ball on the wall" and hamstring curls are ticket. Almost no need to do quad specific moves, as they'll get enough along the way.

While you were dragging the coin with your foot, did you notice anything else? Did you feel like you were falling forward a bit? If so, (and you should have!) you discovered the link to the third law.

For every action...

The third law reminds us that we'll only accelerate in the forward direction when we apply a force in the opposite direction, and if we do, the "reaction" will be moving forward. But here's the catch...if your foot impacts the ground too far out in front of you, the resulting "reaction" will be a deceleration until you engage your (c'mon...) that's right, hams and glutes, to pull your foot backwards. Ideally, your foot would impact the ground with a slight rearward motion already underway. Again, making this happens takes a focused approach, but suffice to say, if you concentrate on "pulling" your foot back just before impact, you've got the idea.

I know this is a ton to take on, so don't despair. The intent here is to explain that running is a complex, dynamic event held hostage by Newton and his laws, and unlike weight lifting, just doing more of it won't necessarily produce the results we want. But since we know these laws, we can get the most out of every step. Until we get the pros out here to fix our mechanics, trade some running time for some leg strengthening, and you'll be ready.