Adizero Adios Pro 4 vs Adizero Adios Pro 5

The Adizero Adios Pro 4 is adidas at its most focused: a carbon marathon racer built to chase a personal best and little else. At 188g it is light for a shoe with this much stack, and the EnergyRods give it a firm, forward-tipping snap that wants you up on your toes and moving. Pair that with a high, responsive midsole and you get a ride that protects your legs deep into a race while still feeling fast. It is happiest on smooth tarmac at marathon and half pace, where a quick, efficient cadence unlocks the best of it. This is not a do-everything trainer, and it does not pretend to be. If you want one shoe for easy miles and race day, look elsewhere. But if you are after a sharp, single-minded racer for the days that count, the Adios Pro 4 is one of the best around.

If you want a lighter, softer ride for the same job, the Nike Vaporfly 4 is the obvious rival.

£220 is a lot for a pair of running shoes, but it's £30 under the Adios Pro 4's £249.99 RRP, and on paper you get more for it. adidas has swapped the old EnergyRods for an ENERGYRIM carbon ring taken from the Adios Pro Evo 3, packed more Lightstrike Pro foam directly under your foot, and brought the listed weight down to 177g. The early reviews are strong. Doctors of Running and RTINGS both rate it best for half and full marathon racing, with a softer, bouncier ride than the Pro 4 and a heel that no longer slips. It's less convincing at 10k pace, where some testers found the soft forefoot a touch less snappy, and it was never meant for easy miles. If you race 13.1 or 26.2 and can hold your form late on, this is one of the first carbon racing shoes we'd shortlist, next to the Vaporfly 4.