Note: I wrote this in 2005. Reading it now, there are certainly some things that I don't agree with, but as a whole, it reflects my thoughts about running technique. The "book readers" among you will recognize some passages of a well-known running book.
The school of thought that argues that one's so-called natural style is not only best but unchangeable represents a defeatist attitude. It ignores the reality that the nervous system has great adaptive capabilities to incorporate subtle changes in data input that create an improved movement pattern. In so many sports-golf, tennis, swimming, gymnastics, and more-the guidance of coaches expert in designing corrective exercises and instructional commands can bring observable changes in style that contribute to improved performance. The same can occur in running.
With each running stride, the muscles of the landing leg store impact energy as they contract eccentrically to absorb the shock of landing. Most of the stored energy is then used during the concentric muscle contraction that propels the body forward during the next stride; that is, we use the impetus of landing to assist the muscular effort of takeoff.
Indeed, there is growing evidence to suggest that the elastic recoil provided by the tendons contributes a significant proportion (about 30%) of the energy for propulsion, at least when running on flat terrain. It is possible that the muscles of the more economical runners have a greater ability either to store or to utilize this form of impact energy.
A popular idea, implicit in the description of how muscles work is that it is the shortening of contracting muscles that propels the body forward when we run. But running is really a series of bounces in which muscles, tendons, and ligaments alternately store and release the energy absorbed as the feet hit the ground. Indeed, it is similar to the action of a pogo stick or a bouncing ball. The realization that the legs alternately store and release elastic energy during running, that this elasticity probably contributes to running ability and possibly also explains some forms of exercise exhaustion.
The most current biomechanical model of leg action during running is that all the elastic elements in the lower leg muscles act as a single linear spring. The stiffness of that spring can be varied, however, particularly in response to the softness of the surface over which the athlete runs. This is important because the stiffness of the spring determines how the body reacts with the ground during the contact phase of the running cycle.
I believe that good running technique is based on the following three aspects:
- Stride frequency – Keeping it above 88 cycles/minute
- Stance time/Support time – Keeping it as short as possible
- Point of impact – Keeping it below the center of gravity
Associated with these three aspects, which can be called primary, are secondary aspects that basically relate to balance issues:
- Upper body balance
- Head position
- Correct tracking of the lower limbs
Daniels is the author that emphasises stride frequency more. Upon studying the stride frequencies of runners in the 1984 Olympics, he found that elite runners from distances from 400m to the 10000m use stride frequencies above 90 cycles a minute.
Most average to good runners, even those with evident technical deficiencies, employ a stride frequency above 90. This variable is also a good way to find runners with a poor technique, so it is always a good point to start when working with new runners.
The stiffness of the leg spring is independent of running speed but alters with changes in stride frequency. Thus, at the same running speed, the leg spring becomes stiffer the higher the stride frequency (and the shorter the stride length). The stiffer the spring, the less energy that will be absorbed. These findings suggest that the naturally chosen stride frequency when running at the same speed by different runners (of similar mass), must reflect individual differences in the elasticity of their legs.
About this technical aspect, I’m always reminded of a quote from Chariots of Fire. When working on the track with the athlete, the coach says “Run like you’re running on a hot plate”. When trying to minimize the support time, that is the exact feel that we want to achieve.
Point of impact
Having the point of impact on the ground as below was possible to the center of gravity (CG) of the body is very simple biomechanics. The further forward the point of impact is from the body’s CG, the longer the “braking” phase of the stride, since forward aceleration can only occur after the support point passes the vertical of the CG.
Upper body balance
The shoulders and upper arms are also important in running. Though they primarily provide balance at relatively slow speeds, they increase in importance in assisting the leg muscles as running velocity increases and as a runner climbs hills. Adequate arm and shoulder interaction reduces the need for counterrotation of the trunk musculature, which is more energy wasteful. Efficient running style suggests that the arms swing fairly loosely and be held quite naturally. Neither should the shoulders be hunched or pulled back, nor the chest thrust out in front. Unnecessarily tensed muscles suggest a needless waste of energy. The shoulders should be carried above the hips.
Arm action varies with running velocity; it is much more vigorous at faster than at slower velocities. Elbows kept close in toward the body minimize the tendency for the hands and lower arms to cross the midline of the chest. Hands and arms normally should only approach the midline. At a wide range of running velocities the elbow joint is flexed at about 90° and remains that way through the range of arm swing. However, at very fast racing velocities this elbow flexion angle unlocks and varies on either side of 90° to provide more fluidity. Arm swing and leg action are inextricably interwoven. If arm swing tends to be erratic, it detracts from optimal style and is energy costly. The hands should be kept loose and relaxed at all times.
The head should be poised well above the shoulders. It is a very heavy piece of anatomy, and if it is not positioned properly, it can cause either of two problems, both bad. If it is too far backward, it places an unnecessary strain on the neck muscles. If it is too far forward, it can restrict the airways and make breathing difficult.
Correct tracking of the lower limbs
This aspect is best exemplified by watching sprinters running. Every movement they make is towards the direction of motion, especially the lower limbs. For a correct tracking of the limbs, a correct activation of the hip flexors is very important.
There is evidence to suggest that uneconomical runners expend more energy bobbing up and down when they run than do more economical runners, who tend to glide over the ground with very little vertical oscillation. Clayton has described how he thinks he became an economical runner:
“When I started training for marathon distances, my style changed naturally. Running 20 miles a day cut down on my stride length. It also eliminated the tendency to lift my knees. Gradually, my power stride evolved into one of economy. Despite the energy-draining action of my upper body, I developed a very natural leg action I call "The Clayton Shuffle. " Through miles and miles of training, I honed my leg action to such a degree that I barely lifted my leg off the ground. "The Clayton Shuffle" is probably the best thing that ever happened to my running. It was economical and easy on my body.”