The arm swing mechanics of elite East Africa (Ethiopia and Kenya) female distance runners is strikingly different from many elite Non-African (American) elite female distance runners.
East African female distance runners present higher arm carriage with greater shoulder swing, torso rotation, and a more suppressed arm swing than many non-African female distance runners.
Arm Swing Mechanics Between American and Ethiopian Female Endurance Runners
Why compare arm swing style between the two groups?
East African female distance runners consistently outperform non-African female distance runners and different arm swing styles affect the rhythmic nature of running gait which may have performance, or injurious implications.
Below, shows the comparison of ‘proper’ arm swing as per Runner’s World magazine to the arm swing of the best female distance runners in the world:
I’m confused. Which arm swing style for running will improve my efficiency and help with injury prevention? Runner’s World suggests that I run, almost like a robot, and to carry and swing my arms differently than the best runners in the world.
Undoubtedly, the arm swing style of most East African female distance runners appears more relaxed and effortless than non-African female distance runners. The suppressed arm swing along with a pronounced shoulder swing and torso rotation allows for greater fluidity in the gait of East African female distance runners.
Comparatively, non-African female distance runners have restrained both torso and shoulder rotation with a back and forth arm pumping motion -robot running, as I call it, which may cause the body to move with more rigidity rather than fluidity. But who cares what I think, what do scientists have to say about the role of the arms in running? Get ready for this.
- a study by Miller et al., found that a suppressed arm swing during running decreased the peak vertical ground reaction force which is a force that is greater in heel strikers and is strongly linked with most running-related injuries
- they also found that with suppressed arm swing, peak hip and knee flexion angle was greater. Knee flexion is higher in forefoot strikers than heel strikers and is considered an impact reducing mechanics of the body
When arm swing is suppressed in running, the arms are essentially combined with the head and trunk into a single segment which represents a net dynamic of the torso. In the study, arm swing suppression increased torso rotation which surprisingly, did not alter lower extremity joint angles. We are told that torso rotation when running is bad, but not according to this study.
- the authors suggested that during running, torso rotation, rather than arm swing, plays a dominant role in counterbalancing the angular momentum of the legs
Funny, the authors ended this statement with “this suggestion should be made cautiously”. Why? Because their data contradicts and discredits, what I consider, out-dated training beliefs on biomechanics. Due to their field crushing domination, it just seems more rational to use East African elite female distance runners as a reliable guide to improve biomechanics, not Runner’s World.
One final note. Most East African runners ran barefoot until adolescence. Some even run barefoot in races in adulthood. Furthermore, less emphasis seems to be on learning biomechanics and more on running in East African runners.
Nevertheless, the arm swing style and upper body motions of East African runners is most likely attributed to running barefoot with a forefoot strike landing style, not a heel strike landing style, in earlier years. However, the effects of torso rotation and arm swing on running economy, impact reduction, and joint kinematics needs to aggressively investigated in habitual barefoot running populations.
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References:
Gerristen, KG., van den Bogert, AJ and Nigg, BM. 1995. Direct dynamics simulation of the impact phase in heel-toe running. J Biomech, 28(6):661-8.
Neptune, RR., Wright, IC., and van den Bogert, AJ. 2000. A method of numerical simulation of single limb ground contact events: application to heel-toe running. Comput Methods Biomech Biomed Engin, 3(4):321-334.
Miller et al., 2009. Ground reaction forces and lower extremity kinematics when running with suppressed arm swing. J Biomech Eng, 131:12.
Bretta Riches
BSc Neurobiology; MSc Biomechanics candidate, ultra minimalist runner & founder of RunForefoot. I was a heel striker, always injured. I was inspired by the great Tirunesh Dibaba to try forefoot running. Now, I'm injury free. This is why I launched Run Forefoot, to advocate the health & performance benefits of forefoot running and to raise awareness on the dangers of heel striking, because the world needs to know.
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