Newton Sir Isaac
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A guidance trainer with a racing flat feel and one that encourages better running form sounds like too much to ask from a shoe but, depending on foot shape and biomechanics, the Sir Isaac delivers it all. It tested light and snug and required a break-in period to get used to hitting a bouncy spot. Forefoot strikers were pushed toward their toes while midfoot runners felt they were running more toward the heel.
Heel fit: Super snug
Midfoot fit: Super close-fitting
Forefoot fit: Narrow
Flexibility: Stiff
Perceived Weight: Light
Barefoot factor: Structured
Cushioning: Somewhat firm
Stability: Very stable
Responsiveness: Bouncy
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