Nike Shox sprung on to the scene in 2001. The unique Shox technology was inspired by the remarkably springy indoor running track at Harvard. Small hollow columns make up the midsole and are mostly made of rubber. And, Nike states that these columns not only absorb impact from heel strike during athletic activities, but they also "spring back" and add more power to your stride. A wide array of Nike sneaker models use Shox technology today, but the original models were the R4 runner, BB4 court sneaker, and the XT4 cross-trainer.