Evolution Running: Letting Off the Brakes© 2005 by Ken Mierke
Intro: Most runners ignore technique, thinking that the way to improvement is to run
more and harder miles. While this generally leads to quick improvement initially, it also
causes many unnecessary injuries and premature plateaus. Our research has shownthat faster runners are more efficient than slower runners.
Most runners ignore technique, thinking that the way to improvement is to run more andharder miles. While this generally leads to quick improvement initially, it also causes
many unnecessary injuries and premature plateaus. My research has shown that fasterrunners are more efficient than slower runners. Efficiency almost always plays a bigger
role in the differences between runners than fitness does. We have found that
correcting technique improves efficiency of runners at all levels by 4.5 to 8 percent 4.5
percent of an hour is 2:42, a huge amount. Would you like to run 2:42 per hour fasterwithout doing more work? Train hard to maximize fitness, but also work on yourtechnique to maximize efficiency.
The easiest way to run faster is to stop slowing down so much on every stride. Mostrunners brake every time their foot hits the ground and then must push off powerfully justto accelerate back up to running speed. Obviously this is inefficient, but few runners
realize the degree of their braking until they learn how to let the brakes off and let their
momentum flow efficiently.
Correct Foot-strike Location
The most devastating error most runners make in their technique is reaching forwardwith the foot before foot-strike. Almost every runner swings the foot forward at thecompletion of leg recovery in an effort to extend stride length. This one simple error
leads to enormous wasted energy and increased risk for injuries for a number of different
reasons.
When the foot hits the ground out in front, the runner’s
leg is not in position to provide propulsion. He has noleverage to pull himself forward, but must wait until hisbody coasts up over the position of the foot. Only when
his body is directly over his foot, can he push off. This
wastes a tremendous amount of energy.
Notice in the diagram that the runner’s center of mass,represented by the square, moves upward as it moves
forward. The runner’s mass does not move horizontally,
but rotates on an upward arc around the position of thefoot-strike. This upward movement of the center of mass causes wasted energy andmuscular fatigue.
This foot-strike location also contributes to braking, the slowing of a runner’s speed at
the moment of foot-strike. From the time the foot first hits the ground to the moment of1

push-off, the runner’s center of mass rises without significant input from the muscles.
Raising mass against gravity requires energy. The source of this energy is a runner’smomentum. Unfortunately, the energy required to do this must be paid back. Using
momentum to raise a runner’s mass comes at a cost of
slowed forward speed. Energy must then be used toaccelerate back to running speed. This energy iswasted on acceleration instead of providing propulsion
for fast steady-speed running.
Efficient runners carry almost all the momentum fromthe previous stride forward into the next stride. The requirement for energy expenditure,then, is only to maintain running speed with almost no energy required for reacceleration
every stride.
Reaching forward with the foot places the leg almost in line with the direction of therunner’s mass, which maximizes impact stress. At the moment the foot hits the ground,a runner’s mass is moving forward and down. As shown in the illustration, an out-front
foot-strike minimizes the angle of deflection. With this small angle of displacement, theimpact of landing provides the foot and leg with a relatively direct blow. Moving the footstrike back underneath the hips provides a much greater angle of displacement,
meaning that the impact of landing is a glancing blow, with less impact delivered to thefoot and leg of the runner and more energy directed forward to maintaining momentum
and running speed.
The single most critical aspect of running technique is the location of the foot-strike,
where the runner puts his foot down. Placing the foot in the proper position relative tothe body minimizes vertical displacement, enables effective use of elastic recoil,prevents braking at impact, optimizes body balance, increases turnover, and decreases
the force required at push-off for fast running.
Many other critical aspects of correct technique build on this cornerstone. Placing thefoot-strike in the proper location is necessary before many other parts of good technique
can be accomplished. While this technique is not at allcomplicated, it may be more difficult to correct than you
would imagine. Correct foot-strike placement is natural forvery few adult runners. While this adjustment may seem
rudimentary and easy to change, almost every runnerautomatically reaches forward with the foot in an attempt
to artificially lengthen the stride. When learning to run withshoes that have a thick slab of rubber under the heel, thisincorrect technique seems natural, automatic, and relaxed.
Correcting the placement of your foot-strike will change
your body position, balance and the basic rhythm of yourrunning. These changes are improvements that will eventually help you run further,faster, and more injury free than ever before, but they will not feel natural initially. Don’t
expect to alter your technique to run quickly and efficiently right away. You have2probably run thousands to millions of steps improperly and correct technique will feel
unnatural and it will take time to adapt.
Efficient runners increase stride length by increasing the power of push-off, not byelongating range of motion. Watch a professional runner, even at four-minute pace, andnotice how narrow the angle between the legs stays. Even at very high speeds, the footnever reaches forward and his legs do not open very wide. Efficient runners legs neveropen wider than about 100 degrees, even when running very fast.
Placing the foot down directly beneath the hips maintains momentum, minimizing any
braking effect caused at foot-strike. The large black arrow in the illustration shows thedirection of the initial force transmitted by the ground at foot-strike. Clearly the out-infront foot-strike sets the runner up for significant braking forces, while the foot-strike
under the hips allows momentum to be carried cleanly
through to the next stride. Accelerating back to runningspeed after braking increases both the energy cost ofsustained fast running and local muscular fatigue in boththe quadriceps and the hamstring muscles.
The key to learning correct foot-strike placement is
simply putting your foot down earlier during leg recovery. The knee will drive forward
and then the foot will swing forward to catch up. Most runners allow the foot to swing
forward past the knee. Instead, just as the foot catches up with the knee, pull back withthe entire leg and put your foot down much earlier than you think you need to. In myresearch on efficient running technique, I have seen thousands of runners swing the foottoo far forward before foot-strike. I have never seen a single runner put the foot down
too early on a single stride.
Movement of Foot at Impact
Most runners’ feet are motionless, relative to the body, when
they strike the ground. The average runner holds his foot out
in front of his body during the flight phase, waiting for gravity topull him down into the ground. Very few runners even think
about this aspect of running technique, but this is one criticalerror which prevents efficient, injury-free running anddramatically increases braking.
When the foot is held out motionless relative to the body until
foot-strike, it is actually moving forward relative to the groundat running speed. Runners create force for propulsion against the ground, using thefoot, in a backward direction. A runner using this technique and running eight miles perhour asks his foot, which is moving forward at eight miles per hour relative to the groundto make an instantaneous sixteen miles per hour change of direction - to accelerate fromeight miles per hour in one direction to eight miles per hour in the opposite direction – allof this immediately and while the runner’s weight is on the foot. Of course, that can’t
happen. This style of running causes excessive braking as the leg muscles contract tochange the direction of force the foot applies to the ground. This slows the runner’s
momentum and requires reaccelerating every step.

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When an efficient runner’s foot strikes the ground, it is already moving backward relative
to the runner’s body, by a magnitude at least equal to running speed. In order to havethe foot drop straight down to the ground, a runner moving 8 mph must have the footmoving backward at 8 mph relative to his body at foot-strike.
Efficient runners swing their legs only slightly in front of the hips and then forcefully pull
the leg backward into the ground before the weight comes down on the foot. Thisprevents braking, conserves a runner’s momentum, and eliminates the need toreaccelerate every stride.
The most effective way I have found to learn to land with the foot underneath the hips
begins with running in place and then very, very gradually accelerates to walking speed
and then to running speed. Moving at extremely slow speeds, a runner has nomomentum to waste, so he has to keep his feet underneath him. Over a period ofseveral minutes, gradually speed up. I often have athletes, even very fast ones, begin
running on a treadmill at 1 mph (60 min/mile), increasing speed by 1 mph each minute.
This may seem silly, but it is very effective.
Another way to work on this aspect of technique takes advantage of the plastic shield ona treadmill. Most treadmills have a plastic shield covering the motor at the front of thetreadmill and a bar about hip height just slightly behind the shield. Running with the hips
almost touching the bar uses the position of the plastic shield to prevent the out-in-front
foot-strike placement.
Learning to pull the foot backward before foot-strike presents a different challenge. Thisis difficult to learn at slow speeds, so practice this aspect of technique at moderately fastspeeds at first. The key is tuning in to the degree of braking so that you can feel thedifference when you get it right and when you don’t. Then the ground becomes yourteacher and will automatically focus your concentration when required.
Video analysis is an amazing tool for improving running technique. Few runners haveever thought about the techniques they use, and many are surprised when they first see
how they actually run.
Improving this aspect of your running technique will improve your speed and efficiency.
It also reduces impact stress, minimizing the risk of injury and post-workout soreness.
The next time you head out on a run, work on letting off the brakes and see how you canrun faster without expending more energy.
Ken Mierke is head coach of Fitness Concepts (www.Fitness-Concepts.com), developer of Evolution
Running (www.EvolutionRunning.com ), and author of the Triathletes’ Guide to Run Training and has
produced a DVD called Evolution Running: Run Faster with Fewer Injuries. Ken is a two-time world
champion triathlete and has coached 6 world champions. Evolution Running clinics are held regularly in
Fairfav, Virginia, Annapolis, Maryland, and across the country.

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