Adizero Prime X 2 vs Metaspeed Sky Paris

The Adizero Prime X 2 is adidas going deliberately over the top. It is a supermaximal carbon running shoe with a stack so tall it sits above the World Athletics limit, which means it is not legal for record-eligible racing. That is the whole point. Freed from the rules, adidas piled on Lightstrike Pro foam and a set of carbon EnergyRods to build a long-run and marathon-training shoe that returns huge energy with almost no legs cost. You feel launched forward once you are up to pace. At 285g it is heavy for a carbon shoe, and the ride is more cruise missile than nimble racer. If you want a legal marathon racer, the Adios Pro 4 is the sibling to buy. If you want the most protective, most propulsive daily and long-run tool adidas makes, and you do not care about race legality, this is it.

The Metaspeed Sky Paris is ASICS at full race trim: a carbon racing shoe built for one job, chasing a personal best on the road. It is the cadence runner's racer, the half of the Metaspeed line tuned for runners who get faster by keeping their stride length and turning their legs over quicker, while the Metaspeed Edge Tokyo handles those who lengthen their stride. At 215g with a full-length carbon plate and a 5mm drop, it is light, aggressive and unmistakably a marathon shoe rather than a do-everything trainer. The bouncy, springy foam and stiff plate work together to roll you forward and reward a committed effort. Hold goal pace and it comes alive. Jog it easy and you will wonder what the fuss is about. In our view it sits right at the top of the carbon racing shoe pack alongside the Nike Vaporfly 4, and at £260 it is priced like the elite tool it is.