Podcast #27: Futuristic Gait & Vertical Oscillations

 Pod #27

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other web based Gait Guys lectures:

www.onlinece.com   type in Dr. Waerlop or Dr. Allen  Biomechanics

Today’s show notes:

1. Neuroscience Piece:


Six months after doctors told him he would likely never walk again after a random accident at home, 49-year-old Chris Tagatac was back on his feet and taking steps, a feat that elated not only him, but also his family.

Tagatac didn’t accomplish this feat on his own, however. He was walking with the help of Ekso, a wearable robot from a company called Ekso Bionics that consists of braces, sensors, and motors that anticipate people’s movements and take steps for them.

2- NEURO 2

For the first time scientists have printed human embryonic stem cells using a 3D printer

The Heriot-Watt University team’s research could eventually lead to human organs being printed on demand and an end to animal drug testing. Jim Drury reports.


3. Vertical Oscilations, Danny Abshire and Running & Walking


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

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.”

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

J Sports Sci. 2005 Jul;23(7):757-64.

Effect of a global alteration of running technique on kinematics and economy.

J Biomech. 2011 Apr 7;44(6):1104-7. doi: 10.1016/j.jbiomech.2011.01.
028. Epub 2011 Feb 20.

Changes in running mechanics and spring-mass behavior induced by a mountain ultra-marathon race.


Revealing the secrets of human gait

A simple measure of the forces involved in walking may help diagnose and treat injuries and arthritis

So the work of Yifang Fan and pals at Jinan University in China is a refreshing step forward (so to speak). Fan and co say they have discovered an independent measure of gait which they call the vertical gait reaction force. This is a measure of the amount by which a person’s centre of gravity raises during two complete steps (with the left and then the right foot).

In healthy adults, and Fan and co have tested 173, this force is symmetrical with regard to left and right foot, a finding they call the principle of least action (in other words, the body does no more than it has to move you around). That’s useful, they say, because no other measure gives this kind of symmetric signal for all healthy people.

In adults carrying an ankle injury or with arthritis, the pattern of force is not symmetrical. That allows a quick diagnosis simply by measuring this force and may in future point to the type of rehabilitation that may treat the condition.

4. Shoe: NB minimus (the new one) and the HI-REZ


 Shawn and Ivo, The Gait Guys