Many runners want to run faster. Improving your speed is often viewed clear indication of progress. In order to run faster, you have to train your body to adapt to the physiological demands of faster running. These demands involve fast-twitch muscle fiber recruitment, increased cardiac output, and lactate shuttling. To elicit these adaptations, you typically want to include some speedwork, such as interval workouts or tempo runs. Yet speedwork increases the risk of injury – and a layoff from running not make you faster.
Fast running itself does not cause injury. Common training errors often associated with speedwork can quickly lead to an injury. Many runners introduce too high a volume of high-intensity running or run their speedwork too fast. With a prudent approach, you can speedwork without getting injured. These tips apply whether you are introducing speedwork for the first time, making your speedwork harder, or doing speedwork for the first time after injury or pregnancy.
Start With Strides
A quick transition from all easy pace miles to hard track workouts bears too high of a risk of injury for most runners. Instead of jumping straight into demanding interval workouts, you can reduce your injury risk by starting with strides.
As described in-depth in this article, strides are a type of speed training with minimal fatigue. Strides typically last 20 seconds and are done at about 1-mile race effort (95% max). Typically, you complete four to five strides when you are starting out. Due to the short duration and sub-maximal intensity, strides are low-risk – but high reward.
Strides provide a neuromuscular stimulus that prepares your body for faster running. You learn how to run fast with smooth, coordinated form. This is a valuable skill for speedwork, since poor form can increase injury risk.
If you are just starting out to speedwork or returning from a long hiatus, begin with four strides once or twice per week. You can do these strides on a flat surface; do not run strides downhill. If you live in a hilly area, you may choose to do uphill strides.
Introduce More Intensity with Hills and Fartleks
Hill repeats are repetitions of running hard up a hill with an easy jog back down the hill in between. Fartlek workouts focus on effort and time rather than distance and pace (read this guide to fartleks for more information). Both of these type of runs will introduce faster running into your training with lower injury risk. Many runners can achieve high power output on uphills but without the biomechanical stress of flat-ground fast running.
One important caveat: if you have a recent history of Achilles or hamstring injuries, fast hill repeats may not be recommended. These workouts place more stress on the posterior chain and could increase the risk of re-injury to those areas.
Begin with hard efforts lasting 30-60 seconds in duration and progress from there. Since these runs focus both on effort rather than pace, you won’t be as tempted to try to run at too fast for your current fitness.
Alternatively, short effort-based fartlek runs offer another safe option. Typically, effort-based fartleks will begin with small doses of time at intensity, such as 8-10 x 1 minute more effort. Depending on your experience level, you can manipulate the recovery intervals in between. For the sample workout, a low-volume runner doing speedwork for the first time could try 8 x 1 min faster/2 min jog. A more advanced runner returning from injury could do 10 x 1 min hard/1.5 min jog. Importantly, these aren’t VO2max workuots – you are picking up the pace, but not pushing super hard.
Intensity Control Matters
There is no benefit in running faster than you should for any given workout. Faster workouts are not better workouts! In fact, going too hard in your speed workouts can increase injury risk.
Just because you can gut-bust out 6 x 800m in 3:00 minutes flat, does not mean you should. Running faster than you need to do in order to obtain the physiological benefits of the workouts will actually work against you. Going too fast for your fitness increases the biomechanical and neuromuscular stress of a workout. Many runners experience deteriorating form from the fatigue also, which further increases injury risk.
You can use pace or rate of perceived exertion (RPE) to set intensity control on speedwork. Heart rate training typically does not work for interval runs, due to cardiac lag. When you run fast, it takes time for your heart rate to reach its peak. This lag makes heart rate unreliable for the start of any interval training.
You can set paces based on recent races. However, know that many calculators, such the Jack Daniels VDOT Calculator, may be too aggressive in the paces provided for newer runners. I prefer the Tinman Running Calculator. To be safe, choose “critical velocity” paces to ensure intensity control as you start speedwork.
Pace can have its drawbacks; many runners may push too hard to hit those paces. Another alternative to gauging intensity is RPE. Since RPE focuses on your perceived effort, you can adjust for any weather or terrain conditions. The drawback of RPE is that it does require calibration. Many runners do not intuitively know what an 8 out of 10 feels like. Although RPE may take trial and error, it is worth learning to judge a workout by effort.
Be sure to know the intended pace and purpose of the workout. There is a significant difference between doing 1K repeats at 10K pace and 1K repeats at your 3K-5K pace. If ever in doubt, veer on the side of caution. It’s better to run a bit too “slow” than run too fast when adding in speedwork.
How Much Speedwork Should You Do?
A variety of factors influence how much speedwork you should do, including your schedule, goals, and injury risk. However, according to recent research the most important determinant for speed work is your overall weekly training volume. No more than 20% of your overall training should be spent at a moderately hard to hard intensity – a concept called 80/20 running.
Importantly, the 80/20 framework applies to peak training. If you are building into speedwork, you will start with less time at high intensity. You may only do 5-10% of your total running at fast paces initially.
Avoid the Trap of Too Much, Too Soon
The introduction or increase of speedwork places new stress on the body. While it can be tempting to ramp up your mileage along with intensity, it simply is not prudent. Increasing mileage and intensity too rapidly at the same time often results in injury or overtraining.
When you add in speedwork, you want to maintain your mileage or slightly decrease it. Allow yourself four or six weeks to adapt to the new stimulus before changing your volume. Once you are adapted to speedwork, then you can gradually increase your weekly running mileage.
Know When to Bail on a Workout
Some days, things just aren’t clicking in a speed workout. This happens to every runner! Sometimes, if it’s just a bit of heavy legs, poor weather, or mental block, you can keep running throughout it. However, there are some runs where it’s better to quit than to push your mind and body past their limits. (Reference this article more on knowing when to quit a run.)
However, if you feel overly fatigued, uncoordinated, or overheated, call it quits on the workout. You never want to dig yourself into a hole of under-recovery or over-training. Even if you are following a well-programmed training plan, you may sometimes need more recovery than the plan accounts for. Do an easy run or simply call it a day instead.
Any increase in training load – intensity, volume, or frequency – requires an increase in recovery. When you add speedwork into your training, you need to add in more recovery. Recovery includes sleep, adequate nutrition and hydration, and rest days. Do not skimp on any of these when adding in more speedwork!
For more tips on how to run faster:
Your Guide to Interval Running Workouts