How to Improve Your Running with the Help of Running Data Analysis

Me at the running laboratory

Applications, gadgets, metrics, and charts – what are they all for?

Perhaps all of this can serve as good motivation for you to not skip workouts or to do them more often.

But the main goal of the data collected by your gadgets is to minimize health risks and improve running performance. Even if you run “for yourself,” it’s much better to know that you are making progress rather than standing still.

Which metrics affect running performance? How do you collect and interpret them? Let’s find out!

Heart rate

Optical Amazfit Verge Lite and Beurer PM25 with the Chest Strap
Optical Amazfit Verge Lite and Beurer PM25 with the Chest Strap

Heart rate (or heart rate variability, HRV) is the best way to get feedback from your body during workouts. Running with consideration of heart rate zones is one of the fundamental principles for both novice and experienced runners. If you’re interested in delving deeper into this topic, you can read a separate article. Here, I’ll give you a brief overview.

What to measure it with? 

Wrist-based or chest strap heart rate monitors. Accurate HRV zones can only be measured under laboratory conditions.

How to improve? 

Depending on your goal, you can choose different heart rate zones to run in (source)*:

  • For recovery after a tough training session, run in the range of 50-60% of your maximum heart rate;
  • For improving aerobic fitness, run in the range of 60-70% of your maximum heart rate. In this zone, the body learns to generate energy from fat; 
  • For improving cardiovascular health, run in the range of 60-80% of your maximum heart rate; 
  • For mental conditioning when preparing for a half-marathon or marathon, run in the zone of 60-80% (the zone in which you can run for a long time) of your maximum heart rate; 
  • For weight loss, run in the 70% zone (Fat Burning Zone) of your maximum heart rate, but remember that this is not a cure-all, as weight loss depends on calorie expenditure rather than choosing a specific heart rate zone (source 1, source 2); 
  • For increasing your anaerobic threshold, run in the range of 80-90% of your maximum heart rate; 
  • For improving speed, run in the range of 90-100% of your maximum heart rate.

*Keep in mind that these are approximate heart rate zones. The actual HRV zones can only be accurately determined under laboratory conditions.

Depending on the type of running workout, you improve your running performance within a specific heart rate range.

  • A low-intensity, non-exhausting short workout that servers to invigorate you is great for recovery. After this kind of workout, you should feel like you could keep running for a very long time;
  • Long runs are done at a slightly higher intensity but still with the feeling that you can sustain that pace for a long time. These runs help you adapt to longer distances physically and mentally;
  • During tempo runs, you get accustomed to running fast and maintaining that pace for a longer duration. Of course, the distance covered in tempo runs is shorter than in long training sessions;
  • Intervals, fartlek, and hill runs are effective methods for speed training and increasing your anaerobic threshold.

All of these types of running workouts are part of a preparatory training program for 10-kilometer races, half-marathons, and marathons. For maximum efficiency and injury prevention, running programs should be designed by a coach, and take into account your current fitness level, physiological characteristics, schedule, and so on.

Professional athletes Chris Leiferman and Bart Aernouts state that they do the majority of their workouts in Zone 2 (commonly known as the aerobic zone, 60-70% of maximum heart rate), which, for one of the triathletes, falls within the range of 120-140 beats per minute.

Your overall endurance also correlates with your heart rate, so the Runtastic blog recommends taking a comprehensive approach:

  • Maintain regularity in your workouts (3-4 times per week)
  • Run longer distances 
  • Incorporate tempo training 
  • Consume more slow-digesting carbohydrates 
  • Ensure proper recovery (sleep, rest, reduce stress) 
  • Work on running efficiency (technique) 

Personally, I have noticed that after extended periods of rest (two weeks or more), I need to gradually increase the proportion of slow-paced training sessions. Once I feel that my body is adapting, I incorporate other types of workouts. Anyone who’s ever been to the gym will be familiar with this: when you start training, you focus on basic exercises at moderate intensity. As you adapt, you choose specific days for targeting different muscle groups such as arms, legs, back, and so on, but you never neglect your foundation.

You can also read a very interesting article about base training in running by Greg McMillan.

VO2 Max.

VO2 Max. reading on Garmin Forerunner 645
VO2 Max. reading on Garmin Forerunner 645

VO2 Max. is a measure of the maximum volume of oxygen (in milliliters per kilogram of body weight) that you can consume per minute during maximum physical strain.

VO2 Max. is an indicator of aerobic capacity, which should increase as your physical fitness improves. It is considered to be a factor influencing and limiting performance in endurance sports (source).

VO2 Max. is not the same as the anaerobic threshold (the point at which lactic acid begins to accumulate due to insufficient oxygen for energy production). You reach your anaerobic threshold much earlier than your VO2 Max.

Below is a table showing the approximate norm for VO2 Max. based on age, taken from the Garmin website:



On Wikipedia, you can find a ranking of athletes with the highest VO2 Max. in history. The leader of this ranking is cyclist Oskar Svendsen with a VO2 Max. value of 97.5 (which is crazy high).

How to measure?

Measuring VO2 Max.
Measuring VO2 Max.

Some sports watches provide approximate information about this parameter based on average statistical data. Accurate measurement of VO2 Max. is done in a laboratory setting with sufficiently long and intense physical exertion to fully engage the aerobic energy system.

Maximum VO2 is reached when oxygen consumption remains constant despite an increase in workload.

How to improve? 

In theory, any training session that goes beyond normal intensity contributes to an increase in VO2 Max. (source).

Most sources state that the most effective way to enhance VO2 Max. is through interval training or any high-intensity workouts (hill running, fartlek, tempo runs).

Heart rate variability

Heart rate variability
Heart rate variability

Heart rate variability (HRV) is literally the difference in time between your heartbeats. So if your pulse is 60 beats per minute, your heart is not actually beating once per second. During that minute, there may be, for example, 0.9 seconds between two beats and 1.15 seconds between two others. The greater this variability, the better shape you are in (source).

These time periods between consecutive heart contractions are known as RR intervals (the spikes you see on an ECG), measured in milliseconds:

RR intervals
RR intervals 

Your nervous system influences the measure of heart rate variability (HRV). The autonomic nervous system, which controls involuntary aspects of physiology, has two branches: the parasympathetic (deactivating) and the sympathetic (activating) systems.

The parasympathetic system processes information from internal organs and monitors internal processes such as digestion and the growth of nails and hair. It also causes a decrease in heart rate.

The sympathetic system reflects the response to things like stress and physical exercise and increases the heart rate.

Heart rate variability occurs due to these two competing branches simultaneously sending signals to your heart. If your nervous system is balanced, your heart constantly receives signals to beat slower from the parasympathetic system and beat faster from the sympathetic system. This is what causes heart rate variability.

Low HRV, and thus an imbalance between the nervous systems, is an indicator that the body is experiencing stress and will not be as productive as it would be with good balance.

The stress indicator, measured by some sports or smartwatches, is based on heart rate variability.

HRV is influenced by a multitude of factors: health status, nutrition, alcohol consumption, intensity and duration of workouts, sleep, stress, age, gender, and even genetics.

HRV is an individual measure, but there are ranges of normality that can serve as a guide for you.

Normal heart rate variability 
Normal heart rate variability 

What to measure with? 

Apple Watch, some Garmin models, Polar, Suunto, and Whoop.

How to improve? 

Optimal training load, reasonable diet (with no alcohol in it), sufficient sleep, and overall healthy lifestyle should optimize heart rate variability.

Elevation gain 

Chornohora Sky Marathon 2021 (Carpathian Mountains)
Chornohora Sky Marathon 2021 (Carpathian Mountains)

The number of meters you ascend during a workout.

Elevation gain during running improves your cardiovascular system.

Don’t hesitate to run slowly on inclines, and don’t sprint downhill.

An interesting topic is altitude training, which is typically conducted by professional athletes. After this kind of training, the athlete’s red blood cell count increases, giving them a competitive advantage.

What to measure with?

Smartphones, sports watches, or smartwatches. There are two measurement options: using GPS data and with the help of a barometric altimeter (more accurate).

Running power 

Running power on Polar Vantage V2
Running power on Polar Vantage V2

Running power (measured in watts, W) is a way to measure the efficiency of the work you do while running. The higher the power, the more energy you generate with each step. The more energy you can generate at a lower heart rate or a faster pace, the more efficient you are.

Power has long been used by cyclists to measure training productivity, but it has only recently been adopted in running.

The advantage of measuring power lies in the limitations of existing metrics.

For example, when it comes to pace, it doesn’t reflect the full effort your body is exerting. Running at 5:00/km on a flat surface versus uphill makes a big difference.

When it comes to heart rate, think about how it reacts to changes in your pace: it doesn’t increase instantly when we start a new fast interval, and it doesn’t decrease instantly when we start a recovery interval. A similar situation occurs when running uphill.

Additionally, heart rate is influenced by many factors other than the work your body is doing during training, so it’s not the best metric for measuring effort (source).

Power is influenced only by your efforts. If you’re running at a pace of 5:00/km on a flat road and expending 230 W, you’ll need to slow down when going uphill to maintain that 230 W.

Unfortunately, power doesn’t take into account heat, wind, and the surface you’re running on. Power is recommended to be used in combination with heart rate. Ideally, using these metrics will allow you to maintain an almost perfect pace throughout the race.

What to measure with? 

Stryd, Polar Vantage V, RunVI 


Matt Hoover - самый тучный финишёр триатлона Ironman
Matt Hoover – the bulkiest Ironman triathlon finisher 

If your goal in running is weight loss, you may have noticed that the calorie values burned during a workout can vary depending on the device you use to measure them.

So can I have a Big N’ Tasty combo meal for dinner if I did intervals today or not?

In 2017, the Journal of Personalized Medicine published a study involving 7 devices, among which the most accurate was the Fitbit Surge with a 27% margin of error. Other devices included Apple Watch, PulseOn, Samsung Gear S2, Basis Peak, Microsoft Band, and Mio Alpha 2, which showed errors of up to 93%.

This is not surprising since there are numerous factors that affect calorie burning, and modern sports watches are simply unable to measure them. The current algorithms are based on your age, weight, height, and physical activity (sometimes heart rate and VO2 max), and they show the average calorie burn results for a person with the same parameters.

For example, if a woman weighing 70 kilograms with 35% body fat and another woman weighing 70 kilograms with 20% body fat both run at a pace of 6:00/km, the device will display the same amount of calories burned. However, the second woman, who has less fat and more muscle mass, actually burns more calories.


In reality, if you’re trying to lose weight, all you need to know is that the difference between consumed and burned calories should be negative. And the smaller the difference, the better.

1 Big N’ Tasty meal contains 525 calories. Running at an average pace of 6:00/km for 1 hour burns approximately 612 calories, so you’ll still have some calories left over for fries!

The fastest way to lose weight through running is to maintain a healthy diet (source).

What to measure with? 

According to the results of the study involving Apple Watch, PulseOn, Samsung Gear S2, Basis Peak, Microsoft Band, and Mio Alpha, Fitbit Surge is the gadget that works best for this task. However, I find it strange that sports watches by Polar, Garmin, and Suunto were not included in the study.



Cadence is the number of steps you take while running in one minute. It is believed that more experienced (faster) runners have a higher cadence, and a cadence of 180 steps/minute is considered the golden standard (according to coach Jack Daniels).

As with any other “universal” metric, there is one caveat here.

Cadence is influenced by running pace (which means you will have different cadences for different types of workouts), the height of the runner, and individual running specifics. Two runners with different cadences can both run efficiently (source).

What to measure with? 

Almost any running app can show you your approximate cadence, even without a sports watch.

How to improve? 

Improving cadence is a natural process if you increase your running speed because running with wide strides of 1.5 meters is just not that comfortable.

Increasing your cadence improves your running technique, but if you abruptly “break” your natural cadence, there is an increased risk of injury. Therefore, simply try running with your natural cadence, making slight adjustments, and observe the results. Don’t change your step frequency abruptly; aim to increase your target cadence by 5-10% (source).

As an option, you can use a metronome (often available in running apps) or music with a corresponding beat frequency, which can be found on

Stride Length

Длинна шага
Stride Length 

Stride length is one of the components of running technique. Since we know that with proper technique, the foot does not land in front of the body but rather under it to minimize resistance, the stride length becomes relatively small.

Each runner has their own ideal stride length (source). There is a very interesting study on this topic that examines three medalists of the World Athletics Championships in the 10,000-meter distance:

  1. Kenenisa Bekele (gold) 
  2. Sileshi Sihine (silver) 
  3. Martin Mathathi (bronze) 

The analysis of a 10-kilometer race revealed the following:

During the first 9 kilometers, the three athletes ran at approximately the same speed. However, their cadence and stride length were different:

  • Bekele had the lowest step frequency (190 steps/minute) but the longest stride length (despite Bekele being much shorter than the other two competitors).
  • Sihine had a higher cadence but a shorter stride length. 
  • Mathathi had the highest cadence but the shortest stride length. 

However, everything changed on the final kilometer:

  • Bekele, who had the lowest cadence, suddenly increased it to 216 steps/minute, becoming the highest, while the stride length remained almost the same. As a result, he won the gold medal. 
  • Sihine increased both his cadence and stride length, securing the second place. 
  • Mathathi increased his stride length, which caused him to lose the highest cadence and finish in third place. 

What to measure with?

Running apps on smartphones, sports watches, or smartwatches.

How to improve? 

Remember that first and foremost, you should run naturally and improve your natural cadence and stride length. Try running in different ways, but make slight adjustments to your body’s natural mechanics.

Ground Contact Time 

NURVV - умные стельки и беговое приложение

This data type represents the duration of time per step when your foot is in contact with the ground during running. This short period of time is measured in milliseconds.

Typically, for professional runners, this time is very brief (often less than 200 ms). Almost all experienced runners have ground contact times of less than 300 ms: they have learned to lift their feet quickly and not elongate their stride.

When the stride is elongated, the foot lands too far in front of the body, leading to braking forces upon impact and an increase in ground contact time (source).

This parameter is influenced by:

  1. The position of the foot relative to the center of mass during landing.
  2. The ability of the muscles and tendons in the leg to generate a rapid force spike.

The good news is that both of these factors can be trained and improved upon (source).

What to measure with? 

Garmin HRM-Run™ or Garmin HRM-Tri™ sensors.

Как улучшить?

Work on your running technique. It is recommended to incorporate 6-8 sets of 10-20 seconds at maximum speed into your training plan alongside regular light runs. Strength training exercises and ones that train explosive power (such as jumps, box jumps, and burpees) are also recommended.

Vertical oscillation 

This parameter indicates the efficiency of running based on how well you propel yourself forward with each step.

The vertical oscillation coefficient is calculated by dividing the “bounce” by the stride length and is expressed as a percentage.

Since stride length is responsible for horizontal movement, it corresponds to the “useful contribution” to running, while vertical oscillation does not contribute to forward movement but only leads to unnecessary energy expenditure.

Therefore, smaller values of the vertical oscillation coefficient correspond to lower energy costs and greater benefits. In other words, running with a lower coefficient is better. (source)

How to measure? 

Garmin HRM-Run™ or Garmin HRM-Tri™ sensors.

How to improve?

Work on improving your cadence.

Ground contact time distribution 

Трейл раннинг

Ground contact time distribution reflects the symmetry of your running and is displayed as a percentage of the total ground contact time. For example, a value of 51.3% with a left arrow indicates that the ground contact time of the left foot during running exceeds the ground contact time of the right foot. If both values are displayed on the data screen, such as 48–52, then 48% corresponds to the left foot and 52% to the right foot.

When developing and testing dynamic running characteristics, the Garmin® team found a correlation between injuries and more pronounced balance deviations in certain runners. When running uphill or downhill, the ground contact time distribution for many athletes usually deviates from the 50–50 ratio. Many running coaches believe that a symmetrical running form is beneficial and efficient. Professional runners typically demonstrate fast and balanced strides. (source)

How to measure? 

Garmin HRM-Run™ or Garmin HRM-Tri™ sensors.


Some metrics are essential to make progress in running, while others can be basically ignored. However, with each passing year, we gain more information, and previously unknown and unused data may eventually become valuable in making our runs faster, longer, and healthier. Living in such a time is exciting!

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