No, it's not my work, but I've found it very informative and thought I would post it here(and also translate it for my Hungarian blog) hoping that it will reach those beginner and not-so-beginner runners who try running for miles like Usain Bolt and are surprised they can't, those who cause earthquakes with their heel-striking, and those who run as if they were about to fall forward or just the opposite, as if they had a spinal fusion. Of course, my intention is not to make fun of anyone, but to help so here we go. Many thanks to David who compiled this and many other highly informative articles.
Why should you care about running form? Well, aside from reducing the potential to injure yourself, running is a series of thousands of steps, and with each step you take you expend a corresponding amount of energy. Over those thousands of steps you can overtake and run faster than a runner of equal ability, with less effort, if you pay more attention to form. This is also known as running economy. It's easy to work on, and is very rewarding to master. You will look and feel like an experienced runner, and in essence will become one much more quickly. You will also enjoy running a great deal more. We've all seen the average weightlifting-type that gets on the treadmill at the gym and pounds away at too fast a speed for five or ten minutes, making an awful racket, then gets off, huffing and puffing as he believes he has finished his "cardio" for the day. This picture I am describing is not intended to make fun of someone who is rightfully just trying to do what seems best. Many good runners don't have a clue of how to follow a proper weightlifting regime.
Running "form", or style, is in many ways a highly individual thing. There are certain components of running form that cannot necessarily be called "wrong", and are based more on opinion, and perhaps personal experience as well. A good example of the grey area of running form in which many esteemed coaches and runners alike differ in opinion is the positioning of the runner's arms - more specifically, the degree of arm bend and therefore, the height at which the hands end up. I am in the camp that believes in a higher, more compact arm position, particularly for long distance runners. Athletes that specialize in middle-distance events tend to use their arms more, and have them in a lower position - think of a sprinter, and you'll understand this difference. However, for most runners who will read this - those who enter 5km races and up to the marathon - my experience tells me that it seems to take a little less energy (and is maybe slightly more aerodynamic) to hold the arms at an angle that is a little tighter than 90 degrees at the top of the arm swing, with the hands near the chest, rather than a lower hand position that finds them along the sides of your shorts. I also believe that it takes a little less energy to hold the weight of the arms when they are higher up. Hold a weighted bar horizontally, then slowly bring it up towards a more vertical position. Notice that there's less energy needed to hold the bar as you get closer and closer to vertical. In fact, if the arms weren't instrumental with balance and driving back to help maintain forward momentum, we would all have them completely bent to vertical and stuck to the front of our shoulders. The degree in which the arms are bent should be at their tightest when the hand is at it's highest point, just before the arm drives back. As the arm moves back and the front of the arm lowers, the angle should relax a little, but no greater than 90 degrees.
A helpful way of looking at proper hand and arm position is to imagine that there are little elastic bands attached to your thumbs, with the other end attached to your corresponding nipple. Your hands should not move towards or away (on the horizontal plane) from the nipple it is "connected to" much more than a couple inches. Runners should certainly have a "driving backwards" motion with their arms, but it needs to be smooth, not wasteful. This is important - many runners have a "pulling" motion, in which they lunge each arm forward, and then back, as if they are grabbing some imaginary object that is helping propel them forward. This incorrect motion is often echoed in the legs - more on that later.
Once you have your hands and arms in the correct position, remember that there is only a driving back motion - the arm starts at the neutral point and then goes backwards, fairly sharply if the runner is moving quickly. There is no real forward segment - only a return to the start position. Think of it as driving the arm back, and then a return to neutral. As you perform the drive back, each elbow should move upwards as it moves back, not outwards (to the left and right). Remember, we are trying to be as aerodynamic as possible, and if your elbows are splayed out, this creates more wind resistance, not to mention forcing the shoulders to unnaturally move inward towards the neck over and over again, as well as likely forcing each hand to cross over to the other side of your chest - another common error in running form. The arm swing is a smooth swivelling motion. Remember the rubber bands? If you are moving your arms correctly, there should be very little horizontal, or forward difference in the length between your nipple and thumb throughout the entire arm swing. If you move your arms too far forward, this length increases dramatically. If you splay the elbows out on the drive back, your thumbs will gravitate towards your outer rib cage. Visualize a smooth, parallel swivel that starts with your hands right in front of your chest, and not going forwards much at all, but simply swivelling your elbows backwards and up in a parallel motion, then returning to the start, remembering once again to not lunge forward. Don't push your chest out while doing this. All breathing in running comes from the belly area, or diaphragm, like a trained singer. If you are female and have taken Lamaze breathing classes in preparation for giving birth, think back to what you were taught in these classes, as proper breathing techniques while running are similar. The upper chest should not visibly be seen to expand! It all happens below this area. Breathing from the chest only allows more waste air to remain in the lungs, as they don't discharge this used air properly. Practice proper "belly" breathing, and you will run faster with less effort, since you will be getting more fuel (oxygen) in with each breath taken.
Your hands will, and should, move up and down, or vertically, as the arm swing occurs. At the top of the arm swing, the hand should be no higher than the shoulder. At the moment in which the elbow is behind the runner at it's highest point, the corresponding hand should be no lower than the bottom of the rib cage. This entire range of vertical hand motion is not much, and should not be exaggerated. Remember to relax the hands, keeping them in a very loose shape that is halfway to becoming a fist. Your thumbs should be relaxed, but pointing up. This helps maintain the correct parallel nature of the arm swing. The hands should be loose and flopping up and down a little with the momentum of the arm swing. Relax your shoulders, and periodically drop your arms to shake out any tension that has built up. This shake-out is best done on downhill sections in a race, if possible, but can be done at any time. Remember, it is almost impossible for the arms to hold tension if the shoulders are relaxed. Arm tension starts in the shoulders, and works it's way down. It is very wasteful on total energy output.
Once you have it all down, you'll feel efficient, and won't be wasting energy with unnecessary hand / arm motions in front of you, as so many runners do. Remember, everything that involves moving yourself forward in running starts at the spot directly under your centre of gravity, and behind you. There is nothing in front of your body that will help you go faster, or in fact move forward at all. This is very important.