Most runners will be familiar with the concept of a long run.
It is considered a staple of the weekly training plan and is precisely how it sounds – a run that lasts longer than the rest of your weekly runs and is generally performed at a steady, easy pace.
However, the long run can vary depending on your experience level and running goals, and one of my favorites to prescribe to my athletes is the fast-finish long run.
Unlike the traditional steady, easy long run, fast-finish long runs involve the runner starting at their normal easy pace and then increasing to their target marathon pace or faster for the final segment of the run.
In this guide, I will show you how to upgrade your long runs with a fast-finish twist and how this powerful workout boosts endurance, simulates race conditions, and takes your training to the next level.
Why Fast-Finish Long Runs Make You a Better Runner
Fast-finish long runs are one of the most powerful tools you can include in your training because they target two essential adaptations that every runner needs.
First, they help your body improve its ability to use fat as a primary fuel source while conserving muscle glycogen.
This is crucial late in a race, especially a marathon, when glycogen levels naturally drop and the risk of hitting the wall increases. These runs also build significant leg strength and resistance to fatigue, teaching your muscles to keep working efficiently even when they’re tired.
Second, fast-finish long runs improve your running economy at race pace. By asking your body to shift from an easier pace into your goal race pace at the end of a long effort (or faster), you train yourself to burn less fuel and stay more relaxed at the speed you want to race.
When combined with traditional long, steady, easy runs, fast-finish long runs round out your training by giving you a mix of endurance, efficiency, and mental toughness. Understanding the purpose of each type of long run helps you get the most out of your training plan.
Perhaps the greatest benefit of these runs is how closely they simulate the final stages of a race. You practice running on tired legs, managing discomfort, staying calm, and maintaining form when fatigue sets in.
Repeating this scenario in training builds confidence and teaches you the mindset and physical control you’ll need to stay strong through the toughest part of the race. By consistently practicing these fast finishes, you become more resilient, efficient, and far better prepared for the demands of race day.
How To Fuel For Progressive Long Runs
When running, your body relies on a combination of fats and carbohydrates for energy. The proportion of each fuel source depends primarily on the intensity of your run.
When running at a slower, aerobic pace, your body can rely more heavily on fat for fuel. This is because aerobic metabolism is efficient at breaking down fat for energy, making it the primary source of low-intensity exercise.
However, when you run faster, your body relies more on carbohydrates for fuel. Carbohydrates provide quick energy because they are metabolized faster than fats, which is crucial for sustaining higher intensities.
For long, easy, steady runs, maintaining an easy pace is critical. At this effort level, your body taps into its fat stores, helping improve your fat-burning capacity—a key adaptation for endurance athletes.
Fast-finish long runs, however, place a higher demand on carbohydrates, especially in the final 30 to 60 minutes, depending on how much time you will dedicate to race pace or faster at the end of your run. This “fast” final block should be no more than 30% of your total run distance or duration.
The focus here is on pushing your body to perform at race-like intensities when it is already fatigued, training it to utilize carbohydrate stores during those critical late-race moments effectively.
Studies suggest1Murray, B., & Rosenbloom, C. (2018). Fundamentals of glycogen metabolism for coaches and athletes. Nutrition Reviews, 76(4), 243–259. https://doi.org/10.1093/nutrit/nuy001 that your body is totally depleted of glycogen stores after 90 minutes of running.
Therefore, you need to consume carbohydrates both before and during to perform well in the “fast” block of the training run. You should try to simulate what you will do on marathon race day when considering fueling.
Related: How Long Should Your Longest Long Run Be?
When Should You Include Fast Finish Long Runs In Your Training?
Make no mistake about it: these types of runs are challenging and mentally demanding.
Alternate fast finish runs with your traditional long, steady long run, and ensure you are not going into them fatigued.
For instance, if you normally do your long run on a Sunday, try to back off a bit on your Saturday training session to ensure you go in mentally and physically fresh.
As these runs can be mentally and physically draining, it is advisable to wait until 8-10 weeks before your actual race before incorporating them into your marathon training plan.
If you start doing them too early, you may peak too soon and reach the start line burned out.
So, the best thing to do is to run long steady runs until 10 weeks out from the marathon date, and then alternate one fast finish long run with a slow steady long run every weekend until you taper.
It’s important to note that only having fast finish long runs in your marathon schedule will not be enough. You need to go through the adaptation process that the slow, steady, long runs provide in terms of improving your ability to burn fat, store glycogen reserves, and handle low blood glucose levels.
How To Structure The Workout
Start by running the last 3 to 5 miles fast on your first fast finish long run, and then increase that distance in the subsequent runs so that you end up running a 20-22 miler with the last 8-11 miles at a faster pace.
Moreover, ensure that this final fast finish long run is 3-4 weeks out from the marathon, as you’ll need time to taper.
Let’s look at a typical schedule for an experienced runner.
Paul has a marathon personal best of 3 hours 09 minutes. This season, he has set himself the goal of running under 3 hours. So, his target marathon pace is 6:50 per mile or 4:15 per kilometer.
A typical fast finish long run for Paul would look like this:
- 10 miles 7:30/8:00 per mile
- 6 miles at goal marathon pace, 6:50/mile
- 2 miles at faster than goal marathon pace, 6:30/mile
- Last 400 meters, give what’s left in the tank
You can adjust the paces to suit you based on your own specific target marathon time.
These long runs are a great addition to a varied run schedule. Take a look at this next guide to switch up your long runs even more:
Def worth incorporating these into the program!
You’ve contradicted yourself a little though on the proportions: if aiming for 30% maximum of run distance then the last 6 of a 16 mile run is quite a bit higher than that? That sounds like it would be challenging… I think I’ll be aiming for fast finish of last 3-4 of my 16 milers – but then I’m an old git!