Running Mechanics, Part III
By Lauren Evans
Note: This is the final article in a series of articles addressing proper form and running mechanics.
Proper running mechanics are vital to improving speed while simultaneously reducing effort. An efficient runner can cover the same amount of distance at the same speed as a less efficient runner with extra energy to spare. The good news here is that running economy is the most trainable part of running if you take to it quickly. Contrarily, other aspects such as VO2 Max and lactate threshold will take a considerable amount of training and time. The entire body should be considered when addressing running mechanics, including the head and shoulders, arms and hands, back and core, hips, legs and foot strike. By improving running mechanics, a runner can lower heart rate, reduce perceived effort, and of utmost importance to most runners-- run faster!
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Running and walking, both fundamental skills, differ from other sports because they are continuous. The over-and-over movements: one foot in front of the other, with the arms moving back and forth at the same time. This continuousness is why injuries are so debilitating to runners. A tennis player with a knee tweak, for example, can still practice the serve and certain other strokes that don’t re-create the movement that causes pain. To practice as a runner, you have to do the exact movements that cause the injury in the first place. Runners push through ‘tweaks’, and the tweaks turn into full-blown injuries. With correct form, the risk of these kind of injuries (known as over-use injuries), can be minimized.
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Back and Core
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The foot-strike is the start of the running cycle. If it strikes underneath or minimally in front of the center of mass, the runner will reduce the braking effect and help carry linear momentum forward. In the running cycle, the foot moves through mid-support after the foot-strike, then snaps toward the buttocks to begin the follow through and the lever action, before pulling forward to initiate the next foot strike. All this is done with the arms moving synchronously. Notice that in describing the main actions of the running technique, any note of the trunk and core area is missing. This is the point – the trunk should move the least amount possible. It is a support system for the lungs and legs of the runner. As your arms swing comfortably back and forth, they don’t cross over the midpoint of the body, thus reducing the chance of trunk rotation. The key is to keep this support system still.
The trunk should have a minimal amount of forward lean in order to reduce the stress placed on the posture muscles. The trunk and head make up over half of body weight and should be kept directly over or just slightly in front of the point of ground support. The feature that most distinguishes running from walking is that in running there is a period where the runner is in mid-air. According to Matt Russ, 2011 Team USA Triathlon Coach, “Running is like flying, with minimal time spent on the ground.”
Stride Length & Frequency
Running economy goes hand in hand with stride length and stride frequency (ground contact time). The optimum stride length for most runners occurs subconsciously but can be developed with practice over time. A change in the optimum stride either by lengthening or shortening can cause energy costs to rise. (Cavanaugh & Williams, 1990) Over-striding can be energy costly due to deceleration caused by the braking effect of the foot strike. Too much swing of the arms and torso can also increase stride length above the optimal distance.
Researchers have found that the world’s best runners have a stride rate of about 180-190 strides per minute. For example, Ryan Hall averaged a stride rate of 182 steps per minute when he set the new sub-1 hour U.S. half-marathon record in Houston in 2007. (Eyestone, 2007) An analysis of NCAA championship videos and elite competition videos enhances these findings.
Application
How can you implement both proper trunk form and elite stride rate in your running? In order to correct the position of your trunk while running, focus on your core and gluteal muscles. By strengthening the part of your body that holds everything upright and in place, you will reduce the risk of injury and become more efficient. To improve your stride rate to the optimal 180-190 strides per minute, focus on the quickness of your turnover during an easy run. Make it feel comfortable, but increase the cadence. Matt Russ often uses a metronome, set at 180 bpm, and the athlete is required to strike the ground at every ‘beep’. Another way to work on stride frequency is by utilizing downhill strides. These must be implemented very carefully as the eccentric movements are very stressful the body. Once a week or once every two weeks, find a gentle downhill slope and allow gravity to ease you into a controlled acceleration as you descend a 50 – 100 meter hill. Make sure you warm up properly, and don’t do more than 4-6 strides. (Eyestone, 2007)
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The Importance of a Coach
As I have stressed in the previous articles in this series, the first step in addressing running mechanics is to be evaluated by a knowledgeable professional coach. A coach can evaluate running mechanics by observing you run and through video stride analysis. By being evaluated, any sub-optimal motion can be pinpointed, and the correction process can begin. Once you have identified what needs to be improved, be sure to focus on one correction at a time to reduce confusion. Once one is corrected, move on to the next improvement in efficiency.
Good luck, and see you on the roads!
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References:
Cavanagh, P., & Kram, R. (1990). Stride Length in Distance Running: Velocity, body dimensions, and added mass effects. In P.R. Cavanagh (Ed.), Biomechanics of Distance Running (pp. 35-63). Champaign, IL: Human Kinetics.
Dallam, G., & Romanov, N. (2001) Developing Improved Running Mechanics. In USA Triathlon Newsletter (US) Pose Tech Corp (2008) www.posetech.com.
Edington, C., Frederick, E.C., & Cavanagh, P. (1990). Rearfoot Motion in Distance Running. In P.R. Cavanagh (Ed.), Biomechanics of Distance Running (135-161). Champaign, IL: Human Kinetics.
Eyestone, E., (2007). Increase Your Stride Rate. Runner’sWorld.com. March 1, 2007: http://www.runnersworld.com/article/0,7120,s6-238-267--11604-0,00.html.
Farrell, J., (1997) Training Implications of Stride Length Analysis. Winter 1997: http://www.coachr.org/stridelength.htm.
Hughes, D. (2008). The Art of Running: A Biomechanical Look at Efficiency. In texastrack.com. Murray, P. (2008).
Slocum, D.B., & James, S.L. (1968). Biomechanics of running. Journal of the American Medical Association, 205, 721-728.
Williams, K. (1990). Relationships Between Distance Running Biomechanics and Running Economy. In P.R. Cavanagh (Ed.). Biomechanics of Distance Running (271-299). Champaign, IL: Human Kinetics.
Williams, K.R. (2007) Biomechanical factors contributing to marathon race success. Sports Medicine 37(4-5), 420-423.