i met team usa's brian siemann, a three—time paralympian who medalled in both the 400 and 800 metre sprints been wearing a unique high—tech sleeve from a start—up called nextiles. you just slide it up, make sure that it is lined up with your elbow. it is the only sleeve in the world that has the technology that wheelchair racers can currently use to actually collect real time cadence data. this first—of—a—kind data comes from biometric threads concealed in the elbow, combined with data from an accelerometer. it's measuring how quickly and how far those fabrics are actually going back and forth, and then giving you real time data so that you can actually adjust your training session. brian uses an aluminium racing chair with carbon fibre features, and his phone attached. you can sort of make adaptions in real time from what you're seeing. yes. that's really cool. well, i'm going to let you crack on. all right. wow. brian's personal best is 400m in 47.84 seconds. holy moley, he's halfway round already. wow, amazing! how easy is it to find technology like this that's tailored specifically towa