Need a lightweight, responsive running shoe? The Energy NR will keep you ahead of the pack! ; Adjusting to Newton running shoes will depend upon several factors including: your current running shoes, your running form, gait efficiency, as well as your speed and flexibility. Those new to natural running form, or those transitioning from a shoe with traditional cushioning will benefit from spending adequate time adjusting. Your body will need time to lengthen the muscles and tendons on the back of the leg and under the foot. Newton recommends first-timers walk in their shoes for several days to become accustomed to the level platform. Walking barefoot on safe and comfortable surfaces can also be helpful. Once ready, begin by introducing short runs of no longer than 15 minutes every other day. Gradually add 10-15 minutes as your feet and leg muscles begin to strengthen. If soreness persists for more than two days, reduce time in shoes immediately. Rest and ice until soreness subsides, then slowly begin introducing time in shoes again. Highly breathable, fast-drying, open mesh upper with Metatarsal stretch panels offers a glove-like fit. Met-flex for enhanced forefoot flexibility. Minimal anatomical support strapping. ETC antifriction and antimicrobial sockliner. Action/Reaction Technology: Highly responsive, trampoline-like and engaging midsole cushioning. High-rebound EVA. Biomechanical metatarsal sensore plate promotes a lighter, more efficient stride. Soft fabric lining. High-density rubber outsole. Carbon rubber heel for extended durability. Imported. Measurements: ; Weight: 8 oz ; Product measurements were taken using size 9, width B - Medium. Please note that measurements may vary by size.