Sunday, September 21, 2008

Shoes - cushioning doesn't matter?

I've previously had posts on shoes.

In previous posts about running shoes I came to the conclusion that shoes should be as simple as possible to avoid interfering with the natural "barefoot" style of walking/running, the gait which we naturally adopt when unencumbered by shoes.

Here is another study which tends to point in the same direction. If you look at magazines, you will realise that running shoe companies spend a lot of money on advertising to promote their various cushioning properties-- air, gels, plastic springs, foam or whatever etc.

This new study found that there was no difference in shoe cushioning after the shoes had been worn for 200 miles. The runners adapted their biomechanics somewhat to cope with th changes in the shoes, but these adaptations were the same in three cushioned shoe types--air, gel, and springs. Conclusion: "Runners should choose shoes for reasons other than cushioning technology." Interesting findings given all the marketing. I doubt that running magazines would promote this study given all the advertising income they get from shoe manufacturers....

Here is the absract:

Running in New and Worn Shoes - A Comparison of Three Types of Cushioning Footwear.

OBJECTIVES: To investigate the effect of shoe degradation on running biomechanics by comparing the kinetics and kinematics of running in new and worn shoes. Three types of footwear using different cushioning technologies were compared. DESIGN: Longitudinal study. SETTING: Pre- and post-tests on overground running at 4.5 m.s-1 on a 20-m laboratory runway; performance measured using a force platform and a motion capture system. PARTICIPANTS: 24 runners (14 males, 10 females). INTERVENTIONS: 200 miles of road running in the same pair of shoes. Within-group factor: shoe condition (new/worn); between-group factor: footwear types (spring/air/gel). Main Outcome Measurements: Stance time was calculated from force data. External loads were measured by maximum vertical force and loading rate. Kinematic changes were indicated by sagittal plane angles of the torso, hip, knee and ankle at critical events during the stance phase. RESULTS: Stance time increased (P = 0.035) in worn shoes. The torso displayed less maximum forward lean (P < 0.001) and less forward lean at toe-off (P < 0.001) while the ankle displayed reduced maximum dorsi-flexion (P = 0.013) and increased plantar-flexion at toe-off (P < 0.001) in worn shoes. No changes in the hip and knee angles. No between-group difference among the three footwear groups or condition by type interaction was found in any measured variables. CONCLUSIONS: As shoe cushioning capability decreases, runners modify their patterns to maintain constant external loads. The adaptation strategies to shoe degradation were unaffected by different cushioning technologies, suggesting runners should choose shoes for reasons other than cushioning technology.


Keith Norris said...

Yeah, I had originally thought that running (intervals) in Nike Frees on asphalt would be brutal. Not so.

I'm waiting for Vibram to develop a sole material that won't get fast-trashed by repeated use on asphalt.

Barefoot on grass, though, is still my go-to for sprinting.


cl2606 said...

Funny...I was just researching this same topic this morning. I did a PubMed search and there appears to be an relavent article from a New Zealand medical journal but it requires a paid membership to read it.

I did find this article though at:
regarding barefoot running and how expensive shoes lead to injuries.