Real-world terrain has its ups and downs, and so should your treadmill. The NordicTrack Elite 1500 treadmill features an incline range of -3 to +15 percent to integrate incline and decline into your training schedule. Training on an incline increases heart rate response and muscle recruitment, while decline training recruits different leg muscles, helping you target and tone your lower body in a totally different way.et the best of both worlds from adjustable FlexSelect™ Cushioning. One half turn delivers for superior impact reduction, with cushioning isolators on each side of the deck, to protect your knees and ankles. Another half turn offers a firm, stable surface that feels like the road to mimic an outdoor run.