Among the skeptics is self-described "proud shoe wearer" runner Spurgeon Hendrick, who regularly hits the trails outside Atlanta, Georgia, for long runs.

CNN: Running debate: Bare or in shoes?

Bangor, meanwhile, have lost striker Marc Lloyd-Williams - last season's top scorer in the League of Wales and runner-up in Europe's Golden Shoe table of goal scorers - to Nationwide Conference side Southport.

BBC: Bangor lay Uefa plans

The Nike workout app tracks a runner's course and computes the distance they've traveled using a shoe sensor.

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