A runner’s typical week of training involve workouts at a variety of paces, ranging from slow, easy runs for recovery and basic aerobic endurance to threshold efforts and race-pace intervals to build fitness for a specific race distance. But perhaps the least-used pace in the average runner’s training is the fastest one—sprint training.
While some runners include a couple of strides once a week to keep in touch with their speed, doing true sprint workouts on a regular basis is not very popular. While this might make sense, as only the last hundred meters or so of a distance race involve actually sprinting, the usefulness of training all-out speed nevertheless merits some scientific investigation.
Can sprint training substitute hard work?
Sprint training gets something of a bad rap as a shortcut for quick results. This is somewhat deserved, given the amount of people touting it as a total replacement for old-fashioned hard work.
Given what we already know from the collective wisdom of thousands of runners putting in traditional training over many years, sprint training will never be a true replacement for easy running, aerobic workouts, and race-specific work, but could prove to be a useful addition to our training regimen, depending on what the science says.
While there have been plenty of studies on the use of sprint training (narrowly defined here as short, high-intensity intervals at speeds well over that of your usual race distance) in untrained people, which usually show that these “high-intensity interval training” or HIIT sessions are quite effective at getting short-term results, we’re only interested in the effects of sprint training in well-trained runners or endurance athletes.
Instead of focusing on whether sprint training is superior to any other kind, we should instead take note of what effect it has on fitness so we can predict when and how to integrate it into training.
Sprint training and fitness
One study which can help us do just that was published in 2005 by Kirsten Burgomaster and coworkers at McMaster University in Canada. Their study investigated the muscular adaptations that occurred in response to six sessions of sprint training (4-7 x 30 seconds all-out with four minutes recovery) spread out over two weeks.
Using eight reasonably fit cyclists, Burgomaster et al. measured a variety of muscular parameters before and after the six interval training sessions, comparing them to changes in a control group which did not do any sprint training.
- After the two-week training intervention, the cyclists showed a significant increase in muscular markers for storing and processing fuel during exercise.
- However, they had no change in their VO2 max, the amount of oxygen they used during exercise.
- The performance of the cyclists in a ride-to-exhaustion improved dramatically as well, moving from 26 minutes until exhaustion to 51 minutes.
The lack of improvement in VO2 max implies that most or all of the improvements in the riders’ fitness came from improvements in muscular efficiency and energy production, instead of the cardiovascular improvements observed when an athlete does traditional endurance training.
Sprint training and performance
The specifics of how sprint training elicits improvements in the muscles was examined in more detail by Dale Bickham and others at Deakin University in Australia. Before and after seven trained runners underwent a six-week training program of workouts with 5-15 second sprints, Bickham et al. measured the levels of biological markers of fast, anaerobic athletic performance in the athletes’ muscles.
Like with Kirsten Burgomaster’s study, the athletes showed a significant improvement in time and distance covered over a run to exhaustion. Bickham et al. linked these improvements to increased levels of a specific type of protein in the muscles called the monocarboxylate transporter 1, or MCT1. This protein functions as a “shuttle” to move lactate in and out of your muscles during exercise, transporting it from your legs to less-stressed areas where it can be reused as fuel.
This could explain why short programs of sprint training appear to have a positive impact on endurance performance, even without any improvements in aerobic fitness: by quickly removing metabolic byproducts from your muscles, you are able to sustain a higher level of energy production over a long period of time.
Biological effects
Increasing levels of one protein, however, is probably not the only important effect of sprint training. In a 2002 review study, Zuko Kubukeli, Timothy Noakes, and Steven Dennis at the University of Cape Town in South Africa extensively examined the biological effects of high-intensity sprint training.
A range of studies demonstrated increases in performance, accompanied by higher levels of biological markers for anaerobic fitness, fatigue resistance, and power production, but many of these studies used untrained individuals. Among the studies of well-trained athletes, sprint training still elicited significant improvements in fitness, but most of the benefits were gained in the first six sessions of sprint training.
Further bouts of sprint-style interval workouts resulted in smaller marginal benefits than the initial six or so, typically spread out over two or three weeks. Kubekeli, Noakes, and Dennis speculate that highly trained athletes respond more selectively to sprint training than sedentary people: because their fitness is already well-developed, their adaptations to sprint training are mostly in the form of better energy production in the muscles and more efficient processing of metabolic byproducts like lactate.
Sprint-style workouts, like 7×30 seconds at near-maximum effort with plenty of recovery are quite different from standard workouts for endurance in distance runners. While these workouts might seem like an attractive shortcut to fitness based on studies of untrained individuals, a well-trained distance runner responds much more selectively.
How to incorporate sprint training into your schedule
Though sprint training can offer distance runners benefits in the form of better management of rising lactate levels and higher energy production in the muscles, it’s not a replacement for the standard workouts that make up the bulk of your training.
To date, scientific research indicates that doing around six sessions of high-intensity sprint training spread out over a few weeks will net you the biggest benefits associated with this type of training.
As with everything else in training, if you’d like to integrate sprint workouts into your routine:
- You should do it gradually—start with only a couple 15-30 second repeats, taking ample time to recover between each. Over the course of several weeks, you could work your way up to more repeats.
- Doing workouts based solely on the testimony of a scientific paper can be a risky endeavor because physiology research is an inherently myopic field of study—benefits at four or six weeks are typically the focus, while long-term results and risks are given relatively less attention. Meaning, don’t focus your training schedule on sprint training for a long period of time. A quick 3-5 week segment, especially after a marathon, and a sprint session every few weeks can get you the benefits you need
- Don’t forget that sprint training will put a lot of stress on your body, given the extremely high speeds associated with it, and could lead to overuse injuries if you don’t ease into it.
Hopefully, this article provided insight into why sprint training is important and how it will eventually help your training in the long-term, even if you’re a marathoner. Remember, developing top end speed takes time, especially if you’ve never done it before. Be patient!
