We have been running track sessions every Wednesday night throughout the summer in Calgary, as we did last summer. These sessions piggy backed off the track sessions that were started by Morgan Alexander, previous Bobsleigh Olympian, and my former employer and mentor. Although Morgan drew out a lot of sliding athletes because of his history as a sprinter and slider himself, many other athletes joined the open track sessions to "Learn How to Run".
This summer, under the umbrella of my little gem, Vital Strength and Physiology, I've tried to continue the tradition of teaching various athletes and general population clients interested in the concept, how to sprint or run. Usually, when we think of running, we think immediately:
- Available to anyone; cheap/free
- Universal; can be done almost anywhere
- Minimal equipment needed
- Everyone knows how to
- Cardi-ohhh boy
Even the cardio-haters have been coming to track this summer, when they realize that there is a lot more to running than just the cardio, or the myth that heel striking is 'bad' for you, or that running will make you skinny. While I'm not going to get into the debate on this blog of whether or not to heel strike, or whether or not running is an effective strategy for body composition goals, I did want to write some notes, thoughts, mechanics, and physiology related to specific sprinting and running mechanics, so that if you hang on long enough and get to the end of this post, you might realize that you too need some training in your running gait, or in the VERY least, to realize that training for running is a complex sport that should be respected as such!
Integration of the hip, back and pelvis in running
The interplay of the hip with the back and pelvis during the running and sprinting gait is essential for proper mechanics, and for utilizing the musculature surrounding these joints efficiently for power and force production. Essentially, the hip is a ball and socket joint with six degrees of freedom of movement:
- Forward flexion (maximum 120 degrees)
- Backward flexion a.k.a. extension (maximum 13 degrees)
- Adduction (maximum 20 degrees) - Abduction (maximum 40-60 degrees)
- Medial/internal rotation (maximum 13-40 degrees)
- Lateral/external rotation (maximum 36-60 degrees)
Hip and knee positions in sprinting
During the first strides of a sprint start (with or without blocks), the forward flexed hip is about 90 degrees when that foot touches the ground. The rear leg should show a neutral ankle, a mostly extended hip (around 0 degrees extension), and a mostly extended knee. Due to strong ligaments attached to the front of the hip and down to the femur, the hip is limited in the extended position. If you drew a straight line over the picture below, the line should start at the back ankle, come up through the knee, the centre of the hip, the back, and through the axis of the shoulders.
Because of the limited extended pelvic position, another phenomenon that should occur is that the sprinter's pelvis should slightly tilt forward when the stance leg is pushing off, in the extended position. Because of this tilting of the pelvis that occurs with each stance phase, the contralateral hip will adjust to accommodate that movement, and the free hip will undulate upwards.
With this in mind, though, if the stance phase when the runner pushes off the ground takes too long, the the pelvis will rotate too far forward, taking too much time to return back to the ready position for the next ground contact.
As the sprinter takes more steps out of the start line, the knee will be less flexed (more extended) when the foot touches the ground on the striking leg, the projection of the torso will progressively rise, the hips will progressively move forward, and the ground contact times will decrease as the sprinter picks up speed.
Ankle positions in sprinting
In terms of the ankle positions during this same sprint start, the sprinter will start with their foot inverted during the swing phase where the ankle gets ready to strike the ground, and then the sprinter will evert their foot as they place it on the ground, creating large amounts of medial rotation in the hip by the end of the support phase of this foot contact.
The arches of the foot are able to change form, depressing to store elastic energy when they contact the ground, and releasing the elastic energy to project away from the ground after foot contact with the track. When the arch is being depressed, it is called pronation, whereas when the arch is lifting or becoming hollow, this is called supination.
When sprinting, we want the athlete co-contracted in their lower limb, to help with stiffness at the ankle joint. Because sprinting occurs at such high speeds, the ground reaction forces change so quickly that the athlete does not have time to adjust to them. Being co-contracted (contracting both the muscles at the front of the shin - tibialis anterior, EDL, EHL, EHB, EDB, and the muscles located at the back of the shin - mainly soleus and gastrocnemius) helps the athlete adjust to any errors in force production that they create with the ground, by optimizing the length of both flexors and extensors, and creating a more optimal muscle length to produce or absorb force. It is for the same reason that throwers abduct their arm to around 90 degrees when throwing a ball, because the co-contractions in adductor and abductor muscle groups balance each other to create optimal force-length, force-velocity, and elastic properties for the throw.
Attractors and Fluctuators
While all the above information is very relevant to having proper form while running, the concept of attractors and fluctuators is a good way to think about the relevant information when coaching or learning proper running. Essentially, the attractors are the key performance indicators, or the components of the running mechanics that should not change from rep to rep, or from person to person (as long as these persons are at a high level of performance). They are marked, as in the image below, by deep well, while the fluctuators are marked by the shallow areas, or hills between the attractors. If you put a marble on one of the fluctuators, it would potentially fall right or left, or stay in it's place. If you put a marble directly into one of the attractors, it would not be able to move at all. This concept is a was of understanding which parts of the performance indicators we want to examine are important. In the case of a sprinter, the shin and ankle angle and it's progression over the course of a sprint start might be an attractor, as it is very key to performance, and does not vary much across sprinters at the highest level. Similarly, high level high jumpers consistently show a hip lock pattern on the hip closest to the mat just before they take off into their final jump. A fluctuator (or less important performance indicator) in sprinting, might be how much the ankle pronates at various stages of the acceleration; similarly the amount that a high jumper pronates or supinates the ankle on the last take off before the high jump is variable between jumpers and between jumps. Keep this in mind as a coach, or as an athlete bogged down by too many performance cues. Train the attractors to form deep wells, and strong motor patterns, while the fluctuators will vary with the environment. Because sport takes place at high speeds, the body has systems that automatically adjust to the changing environment (this example is best pictured as a trail runner running on variable terrain). Think of the fluctuators as the joints that will adjust to the environment, while the attractor states are the constants.
So, do you think you can run?
Or do you think, after reading that quick and relatively basic description of running, that you might benefit from some coaching? Stay tuned for a blog coming out in the near future, explaining the differences in running positions in upright running mechanics (longer distance running or max upright position in shorter sprint), using Kinograms to show graphically what to look for and what to change.
Bosch, F. (2015). Strength Training and Coordination: An Integrative Approach. 2010Publishers.
Bosch, F., & Klomp, R. (2001). Running: Biomechanics and Exercise Physiology Applied in Practice. Philadephia, USA: Elsevier Health, Churchill Livinstone.
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