Many runners and coaches seem to be fond of training at 5K or 10K race pace, designing workouts at those paces. There is not much value to doing that other than to practice specific race pace. While it may seem logical to run at 5K (or 10K) race pace as often as possible to get faster for a 5K (or 10K), it’s not the best (or even a good) way to improve 5K time. It’s better to target the specific physiological factors that influence race performance.
5K race pace is too fast to train lactate threshold and too slow to train VO₂max, and so is not the best use of your training time. Instead, run at lactate threshold pace to train lactate threshold and run at VO₂max pace to train VO₂max. However, if you feel you need to practice specific race pace for the confidence it gives you, then train at that pace to meet the psychological purpose.
When you get REVO₂LUTION RUNNING™ certified, you’ll learn all about how to do workouts correctly.