Benno Nigg weighs into the carbon fibre plate discussion!

Professor Benno Nigg is arguably the most important footwear biomechanist on the planet.

If we go by publication and presence, it is a no contest.  He has also become a friend and huge mentor to me.

So, when he weights into a discussion, I listen. 

He has just co-authored a paper with his colleagues from the Human performance Laboratory at the University of Calgary.

it is entitled:

Does increased midsole bending stiffness of sport shoes redistribute lower limb joint work during running? Journal of Science and Medicine in Sport Volume 22, Issue 11, November 2019, Pages 1272-1277

Now this paper, obviously, is directed at the recent rash of shoes with carbon fibre plates, most notably the Nike 4% and NEXT%, but including the Hoka Carbon X and the New Balance 5280. Saucony are also currently cooking one up!

5280.jpgcarbon X.jpg

                                   New Balance 5280                                                                                         Hoka Carbon X

 

What were the results of the study?

Here is the abstract:

Abstract
Objectives
To investigate if lower limb joint work is redistributed when running in a shoe with increased midsole bending stiffness compared to a control shoe.
Design
Within-subject with two conditions: (1) commercially available running shoe and (2) the same shoe with carbon fibre inserts to increase midsole bending stiffness.
Methods
Thirteen male, recreational runners ran on an instrumented treadmill at 3.5 m/s in each of the two shoe conditions (Nike Free 5.0, Nike Inc., Beaverton, USA, and the same shoe with a full length carbon fibre palte) while motion capture and force platform data were collected. Positive and negative metatarsophalangeal (MTP), ankle, knee, and hip joint work were calculated and statistically compared between conditions.
Results
Running in the stiff condition (with carbon fibre inserts) resulted in significantly more positive work and less negative work at the MTP joint, and less positive work at the knee joint.
Conclusions
Increased midsole bending stiffness resulted in a redistribution of positive lower limb joint work from the knee to the MTP joint. A larger MTP joint plantarflexor moment due to increased vGRF at the instant of peak positive power and an earlier onset of MTP joint plantarflexion velocity were identified as the reasons for lower limb joint work redistribution.   

The practical imlications of this research are as follows:

  • Increased midsole bending stiffness resulted in more positive work performed at the MTP joint and less positive work performed at the knee joint.
  • Higher joint moments at the MTP joint and an earlier onset of MTP plantarflexion joint velocity in the stiff condition were related to redistribution of lower limb joint work.
  • It is speculated that higher vGRF in the stiff condition could indicate potential energy return properties of the carbon fibre plate.  

What does it all mean?

Well, in short, carbon fibre plates work in relation to positive energetic transfer from the knee to the 1st MPJ.

The possible mechanism (science speak for yeah.. this is what happens) is due to potential energy return properties of the carbon fibre plate.

in other words.. it is acting like a lever!

Simple!

Simon Bartold
Director of Bartold Clinical

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