This document discusses the use of performance analysis systems and analytics in elite sports. It describes the UK Sport Innovation Partnership program from 2008-2016 that funded projects to develop technologies to improve athletic performance. Several examples are provided of technical performance analysis systems developed for specific sports like diving, boxing, taekwondo, and curling that record and analyze video and data to provide automated feedback to athletes and coaches. The key principles of performance improvement through these systems include validating data, understanding factors that influence performance, effectively communicating feedback, and changing behaviors.