Hill Running vs Flat running – How Much Do Hills Affect Running Times?

Unless you’re a track runner, most competitions include at least some inclines along with the routine. That means you will often expend much more energy during undulating hill running vs flat running.

But the question is – How much do hills affect running times?

Keep reading to find out how hills can affect your times during an event and how you can calculate the time lost over courses that include hills.

How Much Do Hills Affect Running Times?

When it comes to terrain, we all know a hilly course is always going to be slower than a flat course. But how much does a hill slow you down?

Research done by Jack Daniels years ago calculated that every percent of gradient incline will cost the runner 12-15 seconds per 1.6 km or mile. However, the average gain in downhill running will net you only about 8 seconds per gradient of decline.

Although these numbers aren’t 100% accurate since there are so many variables, the result can give you a good understanding of the time gained and lost over the undulating hill running vs flat running.

However, calculating the incline of a hill or course can be rather difficult for some people. So, tools like GPS watches and training software can help do this for you.

Tools like Trainingpeaks and Strava allow the user to highlight sections and show the distance and incline percentage.

However, if you don’t have access to any software, you can use a GPS running watch instead. Then by a simple calculation, you will be able to calculate the incline of a hill.

Running Gradient Calculator – Calculating Time Lost

First, take a hilly you currently know, then measure the elevation change and divide it by the distance travelled. For example, if you run up a hill that is 152.4m high and is 1524m long, it will give an elevation percentage of 10% ( 152.4/1524 = 10%).

Then to calculate the time lost, we use the Jack Daniels formula. We take the distance above (1524m rounded to 1.6km as an example) and calculate 12-15 seconds lost based on the 10% gradient (15 seconds x 10). The result will give you an estimated loss of around 2.5 minutes.

However, your strength as a hill runner will wholly depend on the time lost. But for a novice runner, it is an easy way to estimate your time over hillier courses.

Alternatively, there is a much easier method to calculate hill running vs flat running times for beginners, and this is the Kelloggs method.

Originally designed by John Kellogg of LetsRun, his calculation focuses on every 10 feet of elevation. So for every 10 feet (3 meters) of elevation gained or loss will affect your time by 1.74 seconds. This method completely removes the horizontal distance that you cover.

As you can see the Kellogg’s method doesn’t differentiate between elevation gained or lost, and for most runners, they know they won’t gain back the time lost running uphill vs downhill.

While this method isn’t as accurate as the Jack Daniels one, it is much more friendly to the novice runner to calculate.

How Often Should You Run Hills?

Knowing the effect that hill running has on your times, how often should you run hills?

First of all, hill training is important to the runner for numerous reasons. They bring variety to the runner’s training and helps to vary the intensity.

However, the importance of running hills is there to build your endurance, speed, power, and anaerobic capacity, making you a faster runner. Knowing how often you should run hills and what type of session you should do is vital to improving your running.

If you’re a new runner, it is important to wait until you have some consistency behind you. That means you should start implementing hills into your training plan once you reach around 15-20 miles (24-32km) per week mark.

Once you reach that volume, you should have attained the conditioning needed to increase the intensity. Starting any sooner puts the body at risk of breaking down, and not to mention the quality of hill intervals will be rather poor.

Start by including a hilly run each week in the beginning. Once you have at least a month of hilly runs behind you, start thinking about adding short hill repeats into your schedule.

Simple sessions like 1-minute hill sprints are a great way to get you started. Remember to build the number of repetitions each week or increase the intensity of the efforts. Then as you get fitter and more comfortable performing a hill workout, look to increase the length.

Hill Running vs Flat running

In summary the majority of your weekly mileage will be covered over flat terrain. No matter if your an elite runner or amateur, hill running will usually make up around 10-20% of your weekly volume. Of course this also depends on the level of the runner and what phase of training you are currently in.

 

Benefits of Running Downhill

As with all uphill running, you must run downhill. Unfortunately, downhill running often gets negative press. That is because of the stress it places on the joints and muscles. Luckily, there are some benefits of running downhill that can help improve your running.

Whether your training for a hilly race or a flat race, downhill running can improve your leg speed and strength. The benefits of downhill running help you improve leg speed by using gravity to teach you to relax at speed.

Running at a speed slightly above your fitness level will also help you develop better running technique. You will teach yourself to control your arm swing and stride length while controlling your center of gravity. All these are beneficial to a runner’s technique.

Downhill running also provides a way to strengthen the muscles and bones. Practicing running downhill will prepare you for a hilly race so the body is already accustomed to the stress that will be placed on it.

As you can see, there are some disadvantages to running downhill, but there are also some benefits to it as well.

Ultimately you want to be careful how much downhill running you do, because of the stress placed on the joints and muscles. So don’t overdo this, especially if you’re a novice runner.