Saucony Endorphin Speed 6

The Saucony Endorphin Speed 6 is the sixth edition of the American brand's most versatile shoe for running fast: great for intervals and tempo runs, which makes it a classic lightweight trainer. Within the Endorphin family it still sits halfway between the Endorphin Azura, which has no plate and is happier at varied paces, and the Endorphin Pro 5, the racer with a full-length carbon plate for race day.

Compared with its predecessor, the Endorphin Speed 5, the real changes are underfoot, although the upper has been updated too. The mesh is light and very breathable, with a thin tongue stitched to the sides that holds the midfoot well and a tall but flexible heel that does not get in the way. The fit is a little snug, as befits a shoe built for speed, and the reinforced toe makes it feel slightly short at first (this eases after the first few kilometres). The big news is the PWRRUN PBX midsole, a beaded PEBA foam that is lighter and much bouncier than the PWRRUN PB of the Speed 5, although it feels firmer for the first few minutes and only really wakes up when the pace picks up. It is paired with a redesigned nylon plate, with slots that make it less stiff than a carbon one and side wings that stabilise the footstrike, and with the SpeedRoll geometry, now more pronounced and clearly reminiscent of the exclusive Endorphin Elite 3. With 2 mm more stack height (38 mm at the heel and 30 mm at the forefoot, 8 mm heel-to-toe drop), the forefoot rocker tips you onto your toes earlier, although that extra liveliness might suit more radical shoes better than a lightweight trainer.

The outsole has little rubber at the heel and cut-outs in the midfoot that look great, showing off the nylon plate mentioned above, but where those annoying little stones can get trapped, so durability remains to be seen and it is best kept on tarmac. Ideal for neutral runners who like the feel of a plastic plate (nylon in this case) and want a versatile shoe that works for intervals as well as tempo runs and races from 10K to the marathon.