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5K Race Pace

This is the pace that you can maintain while racing all out in a 5K. Determining this baseline pace is important because it’s the pace that’s used to determine all your four training pace zones: Easy, Long, Threshold, and Interval Paces. However, running that hard can be difficult to maintain by simply running by yourself, so another way to determine this pace is described in an article on

Run two miles at a steady, conversational pace, then pick it up for the final mile to a speed at which you can speak only in phrases. "Whatever speed you can sustain in that last mile is a good indicator of what your base pace should be," says Cane. A few days later, run three one-mile repeats at that pace (jog 800 meters between each repeat). If your third repeat is at least as fast as the first one, your baseline pace is ideal. But if each mile is progressively slower or you have to walk the recovery interval, adjust your base 5K pace by taking the average speed of the three miles.

Box Plot

A Box Plot (sometimes called a Box and Whisker Plot) is a quick way to tell visually if two data sets are the same or different. It’s a really, really great way to look at data and I could bore you with a lot of reasons why, but I’ll just give you this link instead. 

All you need to know is: if two boxes overlap a lot, the data sets aren’t statistically different. If they don’t overlap, they’re different.

GraphMyRun uses Box Plots to compare your Average Paces from several different runs on one graph on the Trends Page.


The number of steps that you take per minute is your cadence. Most coaches/training plans count the total number of steps taken by both feet (left foot and right foot).  Your GPS file is likely getting it’s information from an accelerometer either from a foot pod, your GPS watch, or your smart phone strapped to your arm so it’s using the single foot strike (or arm swing) method. GraphMyRun checks your average cadence and if it’s less than 100, it doubles it to comply with the more popular definition of cadence.

Most training plans recommend a cadence of 160+ paces/minute.

Easy Pace

The goal of the Easy Pace (also called Recovery Pace) is to promote healing. When run the day after an especially intense work-out, an Easy Pace will flush your muscles with blood to aid in recovery. The key for running a recovery run at Easy Pace is not to run too fast.  Your Easy Pace will feel too easy and won't jibe with the endurance runner’s “more pain is better” mentality. To get the most benefit from an Easy Pace run, resist the urge to run faster. (Using a HR monitor may help.) Remember, the benefits that you get from training occur while the body is healing and recovering — not while you’re actually training. If you never give your body a chance to recovery (by resting or running slowly), you will not get all the gains you deserve from your hard training runs.

Your Easy Pace is between 145 to 60 seconds slower than your 5K race pace.


Grade is a measure of the steepness of a hill. It’s always given as a percentage and is determined by the "rise over the run". (How many feet does the hill go up over a given distance?) Uphills have a positive grade; downhills have a negative one.

For comparison sake, the “grade” of a typical residential staircase is 30-35%. The grade of Heartbreak Hill in the Boston Marathon is 4.5% (A 27 meter rise over a 600 meter run).

Heart Rate Zones

Training plans, such as McMillan Running or Jack Daniel’s The Run Smart Project, set training goals for pace and time/distance to induce changes in your body to help you run better. Typically, you’ll start off increasing your mileage to build a base. Then you may work on speed to improve your running form (and thus your efficiency). There will be runs to increase your body’s ability to convert fat to glycogen (fuel for your muscles). And, of course, there will be easy runs to help your body recover and avoid injury from your training.

Knowing how fast to run is essential for training successfully. A common method is to use a GPS watch to monitor your pace directly. (See Pace Zones below.) Another popular method is to wear a heart monitor and train to a specific effort as determined by heart rate zones.

Of course, heart rate training zones will vary from person to person. They aren’t universal. And your zones will change as you become more fit (and as you age). The method this website uses to calculate heart rate zones was derived by Karkoven. It uses your maximum heart rate (MHR) and your resting heart rate (RHR). To fine tune your training, re-measure your RHR every 2-3 weeks to refine your heart rate zones.

For a complete description of the heart rate zones, read this training article from Runner’s World.

Interval Pace

The goal of the Interval Pace (also called a VO2Max Pace) is to improve running economy by increasing the body’s ability to transport blood and oxygen (your aerobic ability). Oxygen transport is important for endurance runners because glucose can only be broken down in the presence of oxygen. Interval Pace training also improves overall running speed.

This pace is about 10 to 15 seconds faster per minute than your 5K race pace according to or 6-15% faster than your 5K race pace (from the North American Academy of Fitness Professionals as cited on uses a range from 10 to 30 seconds faster than your 5K race pace.) It is approximately the fastest pace that you can maintain for about 10 minutes ( 

Intervals can be run on the track as repeats or as quick exercises in the middle of another run as fartleks. (Fartlek means ‘speed play’ in Swedish. They are bursts of speed during a run for moderate amounts of time.) The total volume of interval training should be no more than 8% of your weekly training according to

Long Run Pace

The Long Run Pace (sometimes called Steady State Pace) is meant to promote endurance. It is the staple of the endurance runners training program. By definition, your Marathon Pace will be within your Long Run Pace range. Your Long Run Pace is 60 to 30 seconds slower per mile than your 5K pace.

The Long Pace promotes capillary growth in your muscles which help increase the volume of blood and therefore the oxygen delivered to your muscles. This pace also promotes the development of mitochondria in your muscles which are needed to utilize the oxygen in your blood. Running long distances and depleting your glycogen stores teaches your body to store more of it — thus pushing the wall farther and farther out. 

In fact, sometimes a training run will have two pace segments: the Long Pace is used for the majority of a multi-hour training run to purposely consume your glycogen stores. The last few miles will be run closer to your Threshold Pace to strengthen you mentally so you know what if feels like to run through “the wall”. These are called “Fast Finish training runs and are meant to prepare you both physically and mentally for your long races.

Long Pace runs are often used early in your training program to build endurance. Later in your training plan, Long Pace runs are used to maintain your endurance and to push your cardio fitness. 


Your maximum heart rate (MHR) is the fastest your heart pumps at sustained, intense exercise. It’s measured in beats per minute. You can determine your MHR by following the instructions at this link. You can also estimate your MHR from your age using the Robergs and Langwehr formula: 205.8 - 0.685 x Your_Age. (That’s the formula that’s used on this website’s Customize page.)

If you determine your MHR and find that you exceed it during one of your runs, don’t panic. By definition, that’s your new MHR. (If it’s way off, it’s also possible your heart rate monitor is malfunctioning.) Remember, your measured MHR will always be more accurate than an estimated value.

Your MHR is determined from your genetics (and your age — it decreases as you get older). Your MHR will not change as you become more fit.

Net Calories

Even when you’re sleeping, your body burns calories to keep your heart beating and lungs working. That means that you're burning some minimum amount of calories all the time. Obviously, when we exercise we burn even more calories and those ‘extra’ calories are the ones that are reported as ‘net calories’.

Net Calories = the calories consumed due to exercise (in this case: running).

GraphMyRun uses the formula described on that fine tunes the net calorie calculation by taking into account your weight and the elevation changes on your run.

Keeping track of the net calories consumed during your training runs is a way to quantify your weekly training intensity. Other methods are to keep track of your Power or Training Intensity.

The value for net calories is proportional to your total distance.

Pace Zones

More advanced training programs employ a method called periodization. This means that you break your training schedule into descrete pieces to work on specific improvements to your running. Often you start building your base with long runs. Then you may work on your running form and speed by running intervals. Other runs are designed to improve your ability to store glycogen.

The key to all these strategies is to run at the right pace. A recovery pace that is meant to flush your muscles with blood to promote healing is much, much slower than a run at interval pace which is designed to optimize the conversion of slow twitch muscles to fast twitch muscles.

Different training plans may call these specific paces by different names. And they may also figure out each pace zone a little differently. Some training plans even have six or more different training zones and the zones may have significant overlap. GraphMyRun takes a simple approach and defines 4 basic training zones:

  • Easy Pace (sometimes called Recovery Pace)
  • Long Run Pace (sometimes called Steady State Pace)
  • Threshold Pace (sometimes called Tempo Pace)
  • Interval Pace (sometimes called VO2Max Pace)

GraphMyRun will determine these paces for you when you enter your own personal running data on the Customize Page. The key is to know your 5K race pace. (GraphMyRun can extrapolate your 5K pace from another race distance using Peter Riegel's  formula.) To generate meaningful training zones, it is important that you enter your time for an event where you were truly racing —  trying to finish in the shortest time possible.

GraphMyRun uses a blend of the recommendations for these four training zones (or their equivalents) from Pete Pfitzinger, Runners World, RunningForFitness, and Garmin. By utilizing the correlations between your 5K race pace and your Maximum Heart Rate (found here and here), the following paces zones are calculated from your 5K race pace:

  • Easy Pace = 145 to 60 sec slower than your 5K race pace
  • Long Run Pace = 60 to 30 sec slower than your 5K race pace
  • Threshold Pace = 30 to 2 sec slower than your 5K race pace
  • Interval Pace = 10 to 30 sec faster than your 5K race pace

These paces are similar (but not exactly the same) as those calculated by Jack Daniels at The Smart Run Project, Greg McMillan at McMillan Running, and the pace zones calculated at Runner’s World. If you prefer to follow those plans exactly, you can enter those paces manually on the Customize Page.

Once you know your pace zones, the Zones Page will show you how long you spent in each zone during your run. All runs should include a warm-up and a cool-down so even if your training plan called for a 3 mile tempo run, you won’t spend all your time at Threshold Pace. But the Zones Page will show you what percentage of your run was spent at your target pace and which splits were spent on pace.

The graph will also show you what percentage of time is being spent between zones. These paces aren’t associated with any specific zone. You should especially be aware of too much time spent between your Easy Pace and your Long Run Pace. These are your “junk miles”. At this pace you’re not running slow enough to maximize your recovery nor are you running fast enough to maximize your endurance.


In physics, work is defined as the force applied to an object times the distance the object was moved. The amount of work done is completely independent of how fast the object was moved. That means the work you do to sprint a mile is the same as the work that you would do to stroll the same distance. Clearly sprinting is harder than walking, so it turns out that work just isn’t a good way to measure how much effort we put into our runs.

Power, on the other hand, is the measure of how fast work is done. Power is exactly the right way to quantify our running effort.

Power can measured in horsepower, BTUs (which stands for British Thermal Units for the curious), joules/sec, etc. A “joule per second” is also known as a “watt” which was named after James Watt, the inventor of the steam engine. These are the same watts we use to describe how bright a lightbulb is. That serves as a convenient reference point so GraphMyRun reports the power exerted for each of your runs in watts.

Power is proportional to the average speed of your run.

Race Time

See 5K Race Time. 

Recovery Pace

See Easy Pace. 


Your resting heart rate (RHR) is the speed your heart pumps when you are at complete rest. The best time to measure your RHR is when you wake up, before you get out of bed. Your true RHR will be even lower than your heart rate when you are sitting still and simply reading a book.

Measure your resting heart rate on several different days to get an accurate value. You can use the same heart rate monitor you use for running (just keep it handy). There is also an app (of course) that’s very simple to use.

Unlike your MHR, your RHR changes as you get more fit; it gets lower. (Because your heart becomes more efficient at pumping your blood when you’re fit, it needs to beat less often to move the same volume of blood when you are at rest.)


GPS units triangulate their position by precisely measuring the time of travel of radio signals to several different satellites in geosynchronous orbits above the Earth. Commercial GPS units have an accuracy of about 3 - 10 meters and ‘ping’ the satellites every couple of seconds. They record the unit's latitude and longitude and the time of the reading in a file (typically a .gpx file). Websites like GraphMyRun decode those files and use that data to figure out your running metrics (like pace and elevation change).

Over the course of a several mile run all those random errors tend to average out.  However, from one reading to the next, a difference of 10 meters is pretty big. And if the last reading put your position a bit ahead of your real location and the current reading errs by placing you farther back than you really are, the distance error will be doubled — which will severely throw off the measurement of your instantaneous pace. (That’s why the ‘current pace’ reading on your GPS unit varies so much while you run.)

GraphMyRun uses two algorithms to reduce this inherent error. 

First, GraphMyRun looks through your datafile to find spikes in the pace calculations. It’s very unlikely that if you’ve been averaging a 9 minute pace for the last minute that you’ll suddenly accelerate and run a 4.5 minute pace for 5 seconds and then settle back into a 9 minute pace again. While you it’s possible that you were running a 4 second fartlek, it’s more likely that there was a statistical fluke in the error of your GPS location.

When GraphMyRun finds a sizable spike (compared to the local average of the data) it assumes that that data point is in error and will replace it the average of the two neighboring points. GraphMyRun filters your data and eliminates outliers behind the scenes.

Even after all those outlying data points have been removed, there will still be a lot of scatter in your graphs. GraphMyRun uses a smoothing algorithm to reduce that scatter that utilizes a weighted running average. You can adjust the amount of smoothing on the Graph page by selecting your preferred smoothing value from the Smoothing drop down button.  A larger smoothing value averages more data at a time and reduces the weight on nearby data points resulting in a smoother graph (at the cost of losing some granularity).

Steady State Pace

See Long Pace. 

Stride Length

A stride is the combination of a step with your right foot and a step with your left foot. (That means your stride count is exactly 1/2 of your cadence which counts each foot strike.) Your stride length can provide useful information about your running form — in particular if you are over-striding. (Extending your leg far out in front of your center of mass and landing on your heel.)

Tempo Pace

See Threshold Pace.

Threshold Pace

The Threshold Pace (sometimes called the Tempo Pace) is the pace at which your body is balanced between producing lactate (a byproduct of burning glycogen in your muscles) and it’s ability to flush lactate from your muscles. Your Threshold Pace is about 8% slower per mile than your 5K race pace according to (GraphMyRun uses a range 30 to 2 seconds slower than your 5K race pace.) It’s about the pace you could run comfortably hard for an hour. At this pace, “conversations" are short, one word answers. 

Threshold Runs increase your overall performance. About 10% of your weekly training volume should be run at your Threshold Pace according to

Training Intensity

In his book, Daniels’ Running Formula, Coach Daniels develops a numerical system to quantify the training intensity of a workout. He argues that running long at a slower pace is the equivalent (in terms of training intensity) as running faster but for a short time. Coach Daniels’ training plans include a targeted weekly Training Intensity value with a mix of slow, long and fast, short runs to achieve a specific overall Training Intensity goal.

Coach Daniels' Training Intensity value is calculated by multiplying the number of minutes run at the appropriate intensity factor and summing the result for your entire training run. There is a table in his book that gives the intensity factors for different workout efforts (as measured by heart rate or vO2Max).

For example, let’s say that from Daniels’ book the intensity factor of your Threshold Pace is .6 and the intensity factor of your Easy Pace is 0.25. According to Daniels, the Training Intensity for a 30 minute tempo run where the first 10 minutes is warm-up (Easy Pace), the middle 10 minutes is run at Threshold Pace, and the final 10 minutes is cool-down (Easy Pace) would be:

Training Intensity = (0.25 x 10 min) + (0.6 x 10 min) + (0.25 x 10 min) = 11

GraphMyRun will calculate the Daniels’ Training Intensity value of your run by using either your heart rate data (which is preferred) or your pace zones. (To be consistent, you should go to Daniels’ running site to determine your pace zones using his system and enter them on this site's Customize page.) 

GraphMyRun will do the math for you and make it simple to keep track of your total Training Intensity if you are following one of Coach Daniels’ training plans.

Training Intensity is proportional to your total distance divided by your average pace.

VO2 Max

VO2 Max is the maximum volume of oxygen that your body can utilize during exercise. Ultimately, your maximal VO2 Max value is capped by your genetics (blame your parents), but you can improve a sub-optimal VO2 Max up to that point by exercise.

VO2 Max Pace

See Interval Pace. 

Z1 (Warm Up)

Zone 1 is the slowest heart rate training zone and is ideal for warm up and cool downs. This zone lies between 50 and 60% of your maximum heart rate (MHR). According to Understanding Heart Rates the body gets its energy from ~10% glycogen, ~5% protein, and ~85% body fat when working out in this zone.

Z2 (Fat Burning)

Like Zone 1, ~85% of your energy comes from body fat stores in this zone. The level of exertion in Zone 2 is fairly light; you should be able to talk comfortably in this zone and maintain activity for a long time between 60 to 70% of your MHR.

Z3 (Endurance)

Zone 3 is also known as the Aerobic Zone and occurs between 70 and 80% of your MHR. Running in this zone will increase the number and size of capillaries. Zone 3 also increases your heart’s size and strength (which will lower your resting heart rate) as well as your lung capacity. Fats and glycogen are metabolized at equal rates in this zone.

Z4 (Performance)

Also known as the Anaerobic Zone, this zone occurs when you run hard — such as interval training. You should only be capable of short phrases or one word answers when using the “talk test” while running in this zone. Zone 4 occurs between 80 to 90% of your MHR and cannot be sustained for long periods. Training in this zone will improve your VO2 Max.

Z5 (Maximum Effort)

Zone 5 occurs between 90 to 100% of your MHR. You’ll enter this zone when you run all out and it can (and should) only be sustained for a few minutes at a time. Sometimes called the Red Line Zone, running in this zone hurts.

© Phil Miller 2014, 2015, 2016