TRAIT ANALYSIS As well as sending 10 pairs of each shoe to runners for trial, we analysed the following data from our US lab

DEEP IMPACT

To measure cushioning, a machine drops an 8.5kg weight onto the heel and forefoot of each pair to gauge how the midsole compresses.

SIZE MATTERS

We weighed men’s size eight models and cut away the upper to find heel and forefoot thickness. This gives us the ‘heel drop’.

FLEX APPEAL

The forefoot is bent to 45 degrees 60 times in 20sec. The force needed tells us how smoothly a shoe moves from heel strike to toe- off.