Extra Cusion = MORE Impact?

By Dr. Cathlin Fitzgerald

As the trend in running shoes moves away from minimalism, many shoe companies have claimed that extra cushioning will reduce impact forces on the body, especially with downhill running. Intuitively, would seem to be true.

Researchers questioned this claim in a study comparing “maximalist” shoes to traditional running shoes. Twenty-seven runners participated and completed four 5-minute runs: level -ground running in traditional shoes, level-ground running in maximalist shoes, downhill running (10% grade on a treadmill) in traditional shoes, and downhill running in maximalist shoes.

The researchers collected data in the final minute of each run, assessing the stride length, footstrike, and loading rates of each runner. Footstrike stayed consistent across shoe use, and stride length was not significantly different. The instantaneous loading rates (the forces loaded into your body), however, increased in the maximalist shoes, doing the exact opposite of what the shoe was intended for!

The maximalist shoes had large amounts of cushion and included an oversized midsole, indicating that this extra material was causing greater impact forces to the body. This is most likely due to a combination of the amount of material and the type of material. Forces can actually increase with too much cushion.

The key takeaway is beyer beware! Heavily cushioned shoes do NOT necessarily reduce impact forces!

Chan ZYS Lau FOY Ching ECK et al. “Does maximalist footwear lower impact loading during level ground and downhill running?”. Eur J Sport Sci. 2018; 18(8): 1083-1089.