Fit

The fit was this shoe’s strong point. The toe box was generous and the midfoot and heel fit my foot to a tee.  One tester noted that “this is the best fitting ASICS shoe that I have worn in recent memory.” The shoe uses Flytefoam cushioning which was just right for efficient runners. It required minimal effort to put the shoe on and take it off which as always an added bonus. The Cumulus 21 fit comfortably with any type of sock blend and/or thickness. The (PHF) technology in the heel also fit so well and kept strides fluid. The additional cushioning around the ankle also allowed for a sock-like fit and prevented heel slip.

Comfort

It was immediately clear during the first run that the Cumulus 21 was a very comfortable shoe and had a great fit for a neutral runner. The more accommodating forefoot fit was just what this shoe needed. The added height in the toe box felt incredible and absorbed impacts well. It seemed that ASICS made the Cumulus 21 less pointy and the result was a toe box that caused no cramping and allowed for great toe splay. This was a shoe that was built for higher mileage and a long life span for training.

Responsiveness

The Cumulus 21 had great responsiveness. The blown Asics High Abrasion Rubber was outstanding. It was pretty flexible and high quality. One runner commented that they had an issue with the forefoot prior to toe-off, noting that it felt a little stiff in the rear part of the midfoot. The toe spring was nice, so the finish in the stride was very good.

Speed

These shoes were decent at turning over the legs. Since they were a little on the heavier side there was a little bit of lag when it came to trying to faster turnover. Not bad by any means, but also nothing like the DynaFlyte. The Cumulus 21 may have been best for some progression runs to gain speed, but I avoided some shorter, interval workouts in these.

Ride Quality

After breaking in the Asics Cumulus 21 I absolutely loved the overall ride quality and comfort of the shoes. There was a lot of cushion in the heel which made this shoe even more appealing for a heel-striker. Due to the different types of cushioning throughout this shoe, the overall ride of the Cumulus 21 was softer than in previous models.