This is a key cycling workout to build your threshold and learn how to maintain your threshold for longer. This was a staple workout example during my training and helped me have solid bike training and race results in ironman and ironman 70.3. This speed workout will build that sustained speed that will allow you to race faster at a top end for longer and build that strength so you don't blow up. Find that pace that will improve your cycling for those bike races and especially for Ironman and 70.3 events.