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Your body wastes a ton of energy trying to regulate its temperature to avoid either freezing or a meltdown. The X-Bionic Medium Running Pant's cutting-edge technology and zone-specific weave manages your temperature for you, which means you have a lot of extra free energy to shave time off your next lap. Woven mesh inserts help circulate air where cooling is needed most, and Intercooler 3D rib technology your keeps specific muscles warmer for optimal performance. A special ExpansionKnee reinforcement insulates from the cold even when the knee is bent, and a pliable fit throughout adapts to your specific body shape without over-compressing anything.