Lactate threshold running is the foundation of training for distances ranging from 5k to marathon. Pushing your threshold pace down gradually increases your fundamental ability to run faster over a given distance. In the middle of your race preparation, try including one threshold pace exercise day into your training week. During threshold runs, you want to feel like you are working hard but not too hard. It's important not to go too fast or too long on these workouts because this could cause injury. Stick to a goal time and keep the effort level high but not so high that you feel like you are about to collapse. If you do feel like you are about to fall over, stop immediately and walk for a few minutes before continuing with your workout or race. It's best to perform threshold runs outdoors under controlled conditions (such as a local race). This will allow you to gauge how you're doing relative to the other runners and apply what you learn during your run to future races/training sessions. Threshold runs are also useful for determining your maximum potential speed over a certain distance. For example, if you can run 15 miles at 85 percent of your maximum effort rate, then you know that you are capable of running a sub-3 hour marathon when the conditions are right. In conclusion, threshold running is vital for preparing you physically and mentally for distance events.