Vertical Oscilations, Danny Abshire and Running & Walking

https://www.facebook.com/photo.php?v=575995729092248&set=vb.111772995514526&type=2&theater

We saw this short 1 minute video by Danny Abshire on vertical movements in running (link is above). Here was the caption placed (by Runner’s Soul) with the video.

• “Danny Abshire, running guru and CTO of Newton Running, explains how vertical oscillation can impede any runner’s performance - did you know that lifting 6 inches with every foot strike can add almost 2.5 miles onto a marathon?”

We are currently trying to find the reference material he used (anyone please forward it to us at thegaitguys@gmail.com).  In theory it makes sense.  Here is an article that shows something a little different. This research article shows shows that minimizing the center of mass vertical movement increases metabolic cost because of the loss of passive mechanical energy from pendulum mechanics. Now, to be fair, apparently Danny was talking about increased distance and not metabolic cost. But what if distance was trumped by energy and time ?  Now there is a neat thought ! We doubt any marathoner would be upset if they ran further than the actual marathon distance but PR’d in the attempt.  One could easily postulate that the term “increased metabolic cost” would mean a slower run time because of the activity being inefficient.

• This study’s findings findings clearly demonstrate that human walkers consume substantially more metabolic energy when they minimize vertical motion.

In this study’s case, it refers to walking, however could it postulate to running as well?  Just something to think about.  As our reading on this topic continues, and as we find supportive and conflicting journal information we will post attachments here amongst our other articles to make sure our readership can see both sides of the peer reviewed research. In Danny’s, and everyone defense, we often find conflicting research in peer reviewed articles, it almost seems at though one can take a stance on any side of a medical topic and find an article to prove the theory, sadly often leaving us nowhere but spinning in place.

Anyhow, the summary of this peer reviewed article by Ortega concluded that :

“in flat-trajectory walking, subjects reduced center of mass vertical displacement by an average of 69% but consumed approximately twice as much metabolic energy over a range of speeds . In flat-trajectory walking, passive pendulum-like mechanical energy exchange provided only a small portion of the energy required to accelerate the center of mass because gravitational potential energy fluctuated minimally. Thus, despite the smaller vertical movements in flat-trajectory walking, the net external mechanical work needed to move the center of mass was similar in both types of walking. Subjects walked with more flexed stance limbs in flat-trajectory walking, and the resultant increase in stance limb force generation likely helped cause the doubling in metabolic cost compared with normal walking. Regardless of the cause, these findings clearly demonstrate that human walkers consume substantially more metabolic energy when they minimize vertical motion.”

In our summarizing of the article it indicated that more vertical motion seems to engage some of the energy conserving pendulum effects of the limbs. We know this happens in the spine. Serge Gracovetsky (“the Spinal Engine”) and many other researchers have discussed this energy conservation by the repetitive coiling and uncoiling of the spinal curves and loading/unloading of the spinal discs.   Here is the journal and abstract below.

Shawn and Ivo, The Gait Guys

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J Appl Physiol. 2005 Dec;99(6):2099-107. Epub 2005 Jul 28. Minimizing center of mass vertical movement increases metabolic cost in walking. Ortega JD, Farley CT. Source

Locomotion Laboratory, Dept. of Integrative Physiology, University of Colorado, Boulder, CO 80309-0354, USA. ortegajd@colorado.edu

Abstract

A human walker vaults up and over each stance limb like an inverted pendulum. This similarity suggests that the vertical motion of a walker’s center of mass reduces metabolic cost by providing a mechanism for pendulum-like mechanical energy exchange. Alternatively, some researchers have hypothesized that minimizing vertical movements of the center of mass during walking minimizes the metabolic cost, and this view remains prevalent in clinical gait analysis. We examined the relationship between vertical movement and metabolic cost by having human subjects walk normally and with minimal center of mass vertical movement (“flat-trajectory walking”). In flat-trajectory walking, subjects reduced center of mass vertical displacement by an average of 69% (P = 0.0001) but consumed approximately twice as much metabolic energy over a range of speeds (0.7-1.8 m/s) (P = 0.0001). In flat-trajectory walking, passive pendulum-like mechanical energy exchange provided only a small portion of the energy required to accelerate the center of mass because gravitational potential energy fluctuated minimally. Thus, despite the smaller vertical movements in flat-trajectory walking, the net external mechanical work needed to move the center of mass was similar in both types of walking (P = 0.73). Subjects walked with more flexed stance limbs in flat-trajectory walking (P < 0.001), and the resultant increase in stance limb force generation likely helped cause the doubling in metabolic cost compared with normal walking. Regardless of the cause, these findings clearly demonstrate that human walkers consume substantially more metabolic energy when they minimize vertical motion.