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Even Marathon Runners Need To Sprint

You’re an endurance runner, surely you don’t need to sprint?

You’re an endurance runner, you don’t need to sprint? New science, however, is making the case that you need some “speed reserve”.


As you adjust your training to race postponements, and/or cancellations, now more than ever is a good time to focus on your areas of weakness. Top speed is probably one that you weren’t thinking about.


We often don’t care to think about top-end speed with the demands of our sport making it a race for the tortoise, not the fare, with the runner who can sustain the best average pace coming home first. Top speed, however, can sometimes emerge as a limiting factor for long-distance running performance according to the works of Gareth Sanford [1] a British research currently working at the University of British Columbia on “speed reserve”. Although Sanford work on “speed reserve”, primarily focusses on 800m runners, a sport with physiological demands that sit at the intersection of speed and endurance, I believe it’s importance to you as a distance runner is often overlooked.


What is anaerobic speed reserve?


Your anaerobic speed is defined as the difference between maximal sprinting speed and the pace that you can sustain at your VO2max (your maximal oxygen update) and is thus a broad reflection of both your maximal aerobic and anaerobic capacity.


Why should you care about your aerobic speed reserve?


Improving your “speed reserve” has obvious direct implications when it comes to flat out running when your competitor kicks at your local park run or marathon, but it can have some indirect benefits too.


While maximum aerobic speed is a reflection of your cardiorespiratory fitness, maximum sprint speed is a function of how you can apply force to the ground. To apply greater force to the ground, you’ll need stiffer tendons, and better neuromuscular signaling, both of which are associated with more efficient running at slower speeds [2,3]. In order words your running economy, how much oxygen it costs you to do what you’re trying to do. You can develop your speed reserve through including all-out short sprints (speed reserve session), plyometrics, and heavy resistance training into your routine.


What are the pillars of an effective “speed reserve” session?


For a “speed reserve” session to be effective, you’re going to need to flip the structure of a long VO2 max high-intensity interval training (HIIT) session on its head. So instead of doing 6,7, 8-minute intervals with 2 minutes recovery, you’re instead going to do intervals as short as 20/25 seconds with a cap on 50 seconds duration. Anything longer and you’re going to start getting a lot of acidification or lactate build up [4].

Speed Reserve Intervals.png

Where do most runners go wrong with these types of sessions?


As endurance runners we tend to struggle with the idea of taking rest between intervals, often caught up on the idea that every session must be specific to the demands of our race. With no rest periods during your race, why should you take rest during a run?


Without adequate rest between these intervals, you’re not going to be able to repeat the same running pace during the next interval owing to fatigue brought on by the accumulation of waste products. Specifically, a decrease in pH levels and an increase of lactate in your blood. Your goal is not to turn this “speed reserve” session into some kind of epic interval session where you leave the session exhausted. This should not be the goal of your “speed reserve” session. Instead, you’re going to want to take rest intervals lasting 90 seconds, between short work intervals lasting 20-25 seconds. This can take the form of an easy jog back to the start line, with time to catch your breath.


Should you use heart rate for “speed reserve” intervals?

Unlike your typical VO2 max HIIT session, heart rate analysis is of little value here. The only real time, when it may be appropriate to consider heart rate during a “speed reserve” interval session is during your recovery periods. In this instance, all you want to do is ensure that your heart rate is coming back down again to a low enough level that you’re getting sufficient rest between your reps, allowing you to repeat that maximal effort again.

Recovery time after this session?


Although you might feel ok immediately post this session, having applied these principles and not turned this into some kind of epic interval session where you’ve left nothing in the tank. You might not even truly experience delayed onset muscle soreness (DOMS), in the immediate 24 hours post. It will, however, begin to kick in after 48 hours. As a result, you’re going to need to respect that you will need recovery time after completing this type of session, and this should be planned for within your training diary.  


(1) Sandford GN, Allen S V., Kilding AE, et al. Anaerobic Speed Reserve: A Key Component of Elite Male 800-m Running. Int J Sports Physiol Perform 2019;14:501–8. 

(2) Saunders PU, Pyne DB, Telford RD, et al. Factors Affecting Running Economy in Trained Distance Runners. Sport Med 2004;34:465–85. 

(3) Jones AM. Running economy is negatively related to sit-and-reach test performance in international-standard distance runners. Int J Sports Med 2002;23:40–3. 

(4) Tschakert G, Hofmann P. High-intensity intermittent exercise: methodological and physiological aspects. Int J Sports Physiol Perform 2013;8:600–10.


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