I received a great question the other day. A long time runner was baffled by exactly what a negative split is and how they should be done. This is a great question and there are lots of answers and ways to approach it. But let me try my best to clear up a few things about this topic.
The negative split is considered the “gold standard” technique for races of just about any distance. Generally speaking, this is when you run the second half of a race faster than the first half. It can be done in any number of ways from running the first half a few minutes slower than the second half, or by strategically running miles at a particular pace for the first half and then a planned faster pace the second half. Taken even further, with experience you can even run each mile of the second half faster than the previous one.
Any of these forms of negative splitting takes a lot of practice and experience. Obviously some require more diligence than others. Typically the first step to this approach begins with you determining a goal pace for a particular event. You can use previous race times to determine a pace you are capable of or take a goal finish time and use pacing tools to determine your base (easy) pace for training. This base pace will be used for the majority of your training runs and will allow you over time to get a feel for different paces. These tools can also help you determine a pace for your speed work and tempo runs as well as long slow distance training. Over time, you will begin to know or at least estimate the speed at which you are currently running.
Either by yourself or with a coach you can then sit down and determine a race strategy. The ability to understand pace by feel will help on race day as you will start the event running a bit slower than what you plan to finish with. This part can be very difficult as it is very easy to get excited in the moment and amongst other runners and go out a bit fast. Using your knowledge of paces from training, you can settle in at a comfortable race speed.
Keep in mind that this is a strategy that should not be used in all daily runs and should generally be saved for speed work, tempo runs, or other strategic training runs. The majority of your runs should be done at your base pace. Even the most elite runners still spend approximately 70% of their training running at their comfortable base pace. There is no need to run negative splits for every run to reap their benefits. In fact, this type of technique can strain your body and lead to injury. Easy runs are meant to be easy runs and you will gain the biggest benefits from this type of training as well. Also keep in mind that beginner runners should focus more on overall endurance training and far less on trying to negative split. While it is the ideal plan for race day, learning to run at a steady pace is a great strategy as well.
Be patient with your body and yourself. Negative splits are definitely an art form that is perfected over time!