Love running? Then you probably hate getting injured?!

OnTracx helps you in running smarter, not harder.

Manage the load you experience as a runner

Too much mechanical load on your muscles and bones is one of the main causes of overuse injuries in running. OnTracx helps you in managing that load based on cutting-edge sensor technology.

Real-time information

Discover how surface, footwear and running technique is related to the load you experience.

Total load

OnTracx calculates the total (cumulative) load you experienced during an entire running session.

Load progression

Find out how much load (in %) you experienced compared to previous weeks, which allows you to gradually increase load and reduce injury risk.

Add context

Assess how the experienced load relates to pain and comfort, and intervene when necessary. 

Knowledge base


The chance you have of
getting injured every year.


The amount of injuries caused by too much load on your body.


Less injury risk if you manage load properly.

With OnTracx you can focus on what really matters when it comes down to injury prevention!

Avoiding injuries is far from easy, so let’s do it together!


Training for a marathon

"By using OnTracx I discovered that there’s a real difference in load depending on the terrain I run on. Now, I use OnTracx to map my load during every running session".


Tech-savvy recreational runner

“OnTracx gives you more confidence that you can run to improve your health without jeopardizing it.”


Experienced runner

“I was surprised by how much load my body has to endure during every run, and how much it changes between runs. I now use OnTracx to gradually increase the load week by week, instead of only focusing on running speed and distance.”


Currently injured runner

”As a currently injured runner, OnTracx is my ideal running coach. It helps me to understand what my body can handle, so I can keep enjoying my weekly runs. Love it”.

Aron Verhaeghe


What I really like is the visualization of mechanical load in such a way that it is easy to understand. Both for me as a professional as for my athletes. I use OnTracx to educate my athletes when it comes down to mechanical loading, and how it relates to the occurrence of overuse injuries.

Jan Victor

Head orthopaedics UZ Gent

Running with lower loads offers long-term benefits in terms of joint health. OnTracx allows you to quantify and subsequently manage that load, and can as such be considered an alternative for knee surgery in patients with mild to moderate knee osteoarthritis.


Recreational runner

“Can’t run without it.”



“As a runner who suffered from injuries before, OnTracx provides me with relevant data and insights in order to rehabilitate in an efficient way.”

E.C. Frederick

Founder Nike Sports Research Lab

Runners, clinicians and the running industry have needed something like this since forever.

Sara Waerlop


OnTracx allows me to gradually increase the load my patients experience, in a valid and evidence-based manner. By monitoring mechanical load in combination with pain and comfort experienced by the patient, it allows me to provide better follow-up during the return-to-run process in a very time efficient manner.


(Start to) runner

”As a data freak, OnTracx is perfect for me. I love to learn more about my body and how it reacts to my training.”

Our first batch of 250 sensors is for those who believe in us.



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Get access to our VIP running community, and get all the tips & tricks you need!

We’ll do everything to help you out! Provide us with feedback, so we can improve the product. 

The future of injury-free running

OnTracx is an award-winning and solution, supported by more than 12 years of scientific research. 

13+ years

Scientific experience


Data points analyzed every minute of your run


steps used for testing and validating the algorithms

How can OnTracx help me right now?

We still have a long way to go, but are taking the first steps together with you. Although OnTracx currently does not tell you what to do or not, it helps you to individualize three main aspects:

Load progression (in %): the load you experienced compared to last weeks.
Too much load on your body, week after week, increases injury risk.
Pain scores (of 10): gives context to your runs.
Manage pain and comfort while gradually increasing the load you experience.
Real-time load (in g-forces): shows the load you experience while running.
Discover how your load changes when changing footwear, surface and running technique

Want to know more about the science behind?

“What heart rate monitors do to improve performance, OnTracx aims to do for overuse injury prevention & rehabilitation.”

Try OnTracx

Here are some Frequently Asked Questions.

We hope we answered them as clearly as possible.

What does mechanical load mean?

The mechanical load is the load that your muscles and bones (of the lower extremities) have to endure during running.

Mechanical load is very different from the so-called ‘physiological’ load, which represents e.g. your heart rate, your breathing and how much energy your body requires during physical activity. 

When the mechanical load becomes too much for your body to handle, overuse injuries, such as stress fractures, can occur. Although it has been possible to measure physiological load already for a long time (via heart rate belts, running watches, etc.), OnTracx is the first to quantify mechanical load in a valid and reliable way.

Why is mechanical load so important in preventing overuse injuries?

Because more than 70% of all running injuries are caused by too much mechanical load. 

Recent scientific evidence shows that many overuse injuries in running occur when the mechanical load a runner experiences is too high for what the body can handle. However, this load is influenced by a number of factors such as running style, surface and footwear choice. As a result, changes in one of these factors can be detected when taking a look at the mechanical load profile of a runner. 

Studies have shown that the experienced load can be very different between runners, even when running at the same pace. Until now, this load is typically measured on a treadmill in very specialized and expensive lab settings (only covering a short period of time). This makes such analyses very expensive and difficult to translate to a real-world context. 

By using the OnTracx sensor and related algorithms, your load can be measured and subsequently managed correctly every time you go for a run, with the ultimate aim of avoiding (another) running injury. 

For whom is OnTracx relevant?

OnTracx is relevant for runners who often suffer from overuse injuries, or for those who want to work on injury prevention.

If you often have overuse injuries, such as stress fractures, cartilage damage or Achilles or patellar tendinopathy, this is most likely due to the fact that your body has been loaded too much, training after training. OnTracx allows you to objectively quantify the mechanical load, subsequently using that information to gradually build up your training program, also taking into account the pain and feeling (comfort) aspects. 

A tip from the OnTracx team: if you never suffered from injuries and have quite some experience in running, then your body might be able to cope with the experienced load! In other words: you are doing well and you might not gain additional benefits from using OnTracx.

On the other hand, in case of pain and discomfort. Always consult a medical professional first.

How should I use OnTracx?

Although OnTracx currently does not tell you what to do (or not to do), it helps you to individualize the following main aspects:

  1. Total (or cumulative) load (in g forces). Total load indicates how much mechanical load you experienced during your entire run (or during an entire week). 
  1. Load progression (in %). This parameter shows you how much mechanical load you experienced this week compared to last week.

  2. Pain scores (score out of 10). Manage pain and comfort while gradually increasing the load you experience. Pain and comfort scores will become even more relevant once we release our updated algorithms!

  3. Real-time mechanical load (in g-forces). Visualizing the mechanical load you experience while running enables you to discover how you can manage the experienced mechanical load, for example by changing footwear, surface or running technique.  

Of course, we advise to consult your running coach for all things regarding your running program and medical doctor or paramedical specialist in case of pain or related symptoms.

How long should I run with OnTracx?

This depends, but in short: the longer, the better.

The longer you run with OnTracx, the more accurate OnTracx can keep up with your load progression. On average, the condition of a runner increases after only four weeks of running. On the other hand, muscles, tendons and bones (significantly) adapt after only six months. That’s why it’s so important to track your mechanical load over time, as this information can then be used in a much better way to drive future benefits. 

If I used OnTracx for a few weeks, I'm done, right?

This depends on you as a runner. 

If you’re a runner that frequently gets injured, or if you are training towards a certain goal, it’s necessary to track mechanical load over time. This is because subtle changes in your training regime, running style, surface or footwear choice can trigger large changes in mechanical load. Unfortunately, you will only be able to tell when it’s too late, i.e. when you’re injured (unless you’re using OnTracx). 

On the other hand, if you never suffered from injuries and have quite some experience in running, then your body is most likely able to cope with the experienced load! In other words: you are doing fine in that case!

How do I know whether I’m a high load runner?

Your mechanical load is shown in a ‘g’-unit. The average runner has a load of about 9g, with a high impact runner showing values above 12g. 

However, it is not straightforward to know whether you are an average, high or low load runner without actually measuring it. Fortunately, from now on you can use OnTracx to know this. In addition, this load can vary greatly from runner to runner. For example, recent studies show that mechanical load can differ between two runners who run a similar distance at a similar pace, with no less than 15%! That’s why we offer runners and the ones supporting them the possibility to know the load they experience- not just after a run, but also during running. 

Should I change my running technique to lower my load?

Changes in running technique can reduce mechanical load, but not necessarily. 

First it’s important to realize that changes in running technique CAN lead to a reduction in mechanical load, but not necessarily. For example, an increase in step frequency (or cadence) results in a reduction of mechanical load for some runners, but in an increase for others. That’s why it’s so important to quantify mechanical load over time. 

If you do change your running technique, then we advise you to do it very gradually (subtle changes) and check based on the OnTracx technology whether it effectively reduces your mechanical load.

How does OnTracx take surface, footwear and running style into account?

Simply put, these parameters can all have an effect on the mechanical load you experience. 

However, these changes are very individual and can thus differ from runner to runner. OnTracx allows you to discover which surface, footwear type and running style have a positive effect (i.e. lower) on mechanical load. In the case of people transitioning during their rehab into a return-to-run phase, the same information can be used to gradually increase the load on their body, while managing the pain and overall comfort levels.

Is OnTracx a medical device?

No, OnTracx is not a medical device.

However, our innovative technology is designed to effectively manage mechanical load on the lower legs during running. Although not a medical device, our solution can be very relevant for injury prevention or rehabilitation purposes. Always consult a healthcare professional for personalized medical advice. Please take a look at our terms of use for further details.

Will I never get injured again by using OnTracx?

Unfortunately, that’s still possible.

Although most running injuries are caused by an excessive amount of mechanical load, they also depend on a high variety of other parameters. This makes it very hard to estimate whether someone will get injured or not, as it is not straightforward to quantify and interpret each of the parameters and their mutual relationships. 

However, knowing individual load profiles can provide valuable information to runners and related healthcare professionals such as physiotherapists. They can use the information to prevent (re-)injury and to optimize the rehabilitation process.

Is there an ‘optimal’ running style to avoid running injuries?

No, there isn’t.

Current scientific evidence shows that there’s no such thing as a ‘perfect’ running style that every runner should adopt, when it comes down to injury prevention or rehabilitation of overuse injuries. There are two important aspects here to remember:

  1. The way you run (also called ‘kinematics’) or your ‘running style’ can change the way your body is loaded, BUT… 
  1. … a certain change in running style (for example increasing cadence or step frequency) can lead to a reduction in the experienced mechanical load for some runners, but in an increase for others. 

As such it is insufficient to only focus on running technique when working on injury prevention, or when trying to rehabilitate from injury. That’s why OnTracx measures the experienced mechanical load on the level of the (individual) runner. 

Should everybody aim to reduce load on their body during running?

Absolutely not. 

One of our most important pieces of advice is: if you don’t often suffer from injuries, keep on running as you are. Altering running style and/or training regime can also have a reverse effect, especially when drastically making changes in a short period of time (which we advise not to do). 

Consequently, our product is not doing any magic, nor is it a quick fix for all running-related injuries. Instead, with OnTracx we aim to add relevant information that will help people make personalized decisions. In case of severe health issues or pathologies, we always advise to reach out to a medical professional.

For which type of running-related injuries could OnTracx be useful?

Especially tibial stress fractures, plantar fasciitis, Achilles tendinopathy and patellofemoral pain have been shown to be related to a very high variety of parameters of which an excessive amount of load is considered the most crucial one - by far! Managing load has already been shown as the most effective way to successfully reduce running injuries. 

What does the OnTracx sensor measure exactly?

The OnTracx sensor measures the acceleration of the tibia (or shin bone) during running. 

Scientific research showed that the peak of this tibial acceleration (PTA; this is when the foot hits the ground) is strongly related to the shock or impact measured in the lab. As such, OnTracx allows measuring the impact or shock for every step, in an outdoor setting (where and when it really matters). This allows runners to work on injury prevention based on load measures. In addition to this, we’re also developing more advanced loading metrics. More on that soon!

How accurate is the measurement?

Here it gets a bit scientific, but the correlation between the signal from the sensor and the laboratory measure shows a very strong correlation of r = 0.91. 

This means that our sensor-based measure is almost the same as the load parameter calculated in lab-settings. As a spin-off from Ghent University and its Sport Science Laboratory - Jacques Rogge, we care about the accuracy and validity of our product, and do not aim to create something that looks good but doesn't really do the job. 

Our measurements have been validated with the so-called ‘golden standard methods’. This means that we checked - and verified - that the load measured by Ontracx is similar to the one measured in specialized laboratory settings. This however doesn’t mean that our product is perfect. It just means we’re confident that what we’re measuring is correct enough to be used in real-world settings.

What’s different between OnTracx and other wearable (running) devices?

There are quite some other running tools out there, but they all have a different purpose compared to OnTracx. 

While many other (wearable) technologies focus on how to improve performance, the focus of OnTracx completely lies in the injury prevention and return-to-run areas. We’re one of the first to quantify mechanical load in an evidence-based and reliable way, and translate this type of information to all runners out there, with only one goal: reduce the millions of running injuries worldwide.

Why is it placed around the lower leg?

We strategically placed the sensor on the lower leg because, during extensive testing, it proved to be the most reliable location to measure mechanical load during running. Here's why:

Specificity: The lower leg experiences the first rapid deceleration as your foot strikes the ground. Which only can be captured by measuring at that specific location.

Consistency: Unlike other locations, such as in the shoe, on the laces, or on the lower back, attaching the sensor around the lower leg minimizes interference from external factors and ensures your data reflects actual running load.

Validation: Through rigorous lab testing, we found that the lower leg provided the most accurate and reliable data.

How should you attach the sensor around your leg?

It’s important to place the sensor the same way every time you go for a run. Here are some guidelines for proper sensor attachment:

Place the sensor about 10cm above your inner ankle, on the flat part of your shin bone. Always attach the strap firmly, in a similar way, and on the same leg (we advise to put it on the leg that suffers (most) from running injuries). 

To make this more clear, we made a video that shows you how to attach it exactly!

With which smartphones can I use OnTracx?

It is hard to test all devices out there and bluetooth can sometimes become an issue. However, we keep an updated list of the tested devices right here. If your device is not listed, it does not necessarily mean that it will not be compatible, and it might be interesting to reach out before buying OnTracx.