Running technique determines running efficiency, as well as what top speeds you can reach. Understanding your technique can also help you predict areas where you are prone to injury and where you can improve through specific strengthening.
In this article, I will look at Lauren Fleshman's stride at 5,000m pace and the main actions that occur. Included will be what makes the actions effective and, in some cases, in need of improvement. Keep in mind that the main actions that occur in the 5,000m are the same as the actions that occur in other running events. The only differences are in the amount of force generated and range of motion in the joint actions at each distance.
Focus will be on the three major force-producing actions: push-off, knee drive and pawback. You can track Lauren's stride on the above sequence through these phases. The push-off is the primary action needed to supply the force to drive you forward. The force comes from a powerful contraction of the calf muscle that is responsible for ankle joint extension, the main action involved in the push-off. The knee drive, which is coordinated with the push-off, supplies additional forward momentum. In the knee drive, the thigh is driven forward from a position behind the body to in front of the body. The height of the thigh at the end of the drive phase is determined by the force generated by the hip flexor muscles. The leg is then straightened and brought backward and downward in a "pawback" action to make contact with the ground.
The key action that occurs in the push-off is ankle joint extension. Push-off is not, as commonly believed, caused by the glutes and hamstrings being involved in hip joint extension or the quadriceps driving knee joint extension. Observe the ankle joint in frames 6-9, and you can see it goes through a substantial range of motion.
Ankle joint extension should occur when the supporting leg is behind the body. If ankle joint extension takes place early–when your body directly over the foot during the support phase–you will project the body more upward rather than forward. As a result, your run will be more up and down rather than remaining basically level and moving horizontally.
If you look closely at the sequence of Lauren you'll see that there is some up-and-down motion. This indicates that the major force action occurs when her body is nearly above the support leg rather than farther out in front of the support leg. This is typical of most long distance runners and is usually considered an indication of effective running. In this case the force of the ankle joint extension still propels her mostly forward, not upward.
During the push-off, you'll notice Lauren maintains a slight flexion in her knee joint (frames 1,8), which is efficient and helps with keeping the force horizontal instead of vertical. Near the end of the push-off (frames 3, 9) it appears there is some hip extension but this is due to the rotation of the pelvis. During the initial support phase there is no back arch and she is in a slight crouch with some spinal flexion (frames 7, 14), then the pelvis rotates forward so that there is a slight arch in the lumbar spine. The crouch actions are needed to help absorb some of the landing forces.
As the push-off takes place, the free (swing leg) knee is driven forward via hip flexion. This action is commonly known as the knee or thigh drive. It plays an important role in regard to maintaining or increasing stride length. In most 5,000m runners the thigh is driven forward so that it rises up approximately 40 to 50 degrees to the vertical. Lauren exceeds this range, which is usually indicative of a faster run (frames 2, 9). She's pushing it somewhat faster than 5,000m pace here, and the extra knee lift would cost some energy in a longer distance race.
Note that the knee is driven forward, not upward, so that you gain horizontal speed rather than vertical height. The more vertical your push-off is, the more energy you expend and the sooner you bring on fatigue. It has been estimated that if you raise your center of gravity by only 1 cm on every step in the marathon you would have expended an amount of energy equal to climbing the Empire State building.
At the end of the push-off, you'll note that Lauren raises the shin of the trailing leg so high that she almost kicks herself in the buttocks. Although many top runners exhibit this action, particularly when accelerating, it is typical of a sprint; it is not needed at 5,000m pace and wastes energy in a long event. Ideally, the shin should be carried slightly above level during the knee drive.
If Lauren would concentrate more on ankle joint extension so that the foot and leg would push more backward to propel her more forward rather than upward, in addition to driving the thigh more forward, she would be able to have a longer stride and use even less energy.
As the thigh reaches its maximum height and the push-off is completed, the runner is now airborne and prepares for touchdown. The shin of the forward thigh swings out in a leg-straightening action and is then pulled backward, in an action known as pawback, to make contact with the ground. This is needed for two important reasons: to eliminate or greatly minimize braking forces that occur if your foot lands in front of your body and to help propel your body forward so that your center of gravity is as far forward as possible prior to the push-off. Note the angle of Lauren's lower leg from full extension to ground contact in frames 4, 5, 6, 11, 12 and 13.
On Lauren, touchdown is good, as it occurs midfoot and sometimes ball-heel, so she is not braking. In addition, it appears that she bends the knee to initiate contact and absorb landing forces.
The pawback action executed by Lauren is minimal, however, as she quickly drops the thigh of the swing leg instead of holding it up as the shin swings out (frames 3, 4, 5 and 10, 11, 12). Because of this, she makes contact with the ground earlier than needed, reducing the length of her stride. The pawback can best be seen in sprinters, and is often weak in distance runners. Only the very best (such as Sammy Wanjiru) demonstrate a full shin extension and pawback during the flight phase of their stride. Pawback can be improved by strengthening the hip flexor and extensor muscles.
(click on picture for larger image)
Effective Secondary Techniques
Some high-level runners make up for deficiencies by having fairly effective secondary technique characteristics. This includes an erect or tall body position while running, relaxed arms and shoulders, elbows kept at a 90-degree angle for greatest economy in the arm swing in long-distance running, and a good counteraction between the shoulder and hip rotation.
For example, an outstanding feature of Lauren's form is the minimal amount of shoulder and hip rotation. Most seems to occur when she pulls her right arm back behind the body more than needed. She does not do this with the left arm, however. This is not unusual, as we all have minor discrepancies between what the left and right sides of the body do.
Her posture is good but may be improved by maintaining an even more erect position (perfectly vertical as opposed to the approximately 5-to 10-degree forward lean posture at push-off). It may be due to too much of a crouch position during support. This correction may enable her to run even more smoothly.
Looking at the sequence, Lauren Fleshman provided a "key words" description of what's going on in her head at each stage:
1. strong foot, drive forward
2. float, swing through, relax
3. float and land foot underneath me
4. don't let the back leg lag behind
5. heel to butt*
6. heel to butt, feel the ground, prepare to react
7. reload foot, reload swing leg, like a coiled snake
8. swing through
9. strong foot, drive forward
10. float, swing through, relax
11. float and land foot underneath me
12. heel to butt, feel the ground, prepare to react
13. reload, coiled snake
14. swing through
* She adds: "I think at the higher speeds, you have to bring your heel to your butt, and the fastest distance runners are running pretty fast the entire time. But Yessis is correct in that mine is a bit exaggerated. I was focusing on my form so much when I ran for those shots that I was most likely exaggerating slightly compared to what I would normally do. So yes, Yessis is right: During the majority of a race, before the finishing kick (1,000m out or less), my heel shouldn't go as high."
Michael Yessis, Ph.D., is professor emeritus at Cal State Fullerton and the author of Explosive Running.