Do Force Platforms, Pressure Sensors And Smart Insoles Do The Same Thing?

Force platforms, pressure sensors and smart insoles are all devices that a person can step on and get some insight related to their weight or the pressure they are exerting on those devices with each step. Other than that, they are quite different and can have very different applications. This post is just an attempt to break that down. Feel free to jump to the different sections that are of interest:

[Force PlatformsPressure SensorsSmart InsolesSummaryMore on Smart Insoles]

Force platforms

A Force Platform (FP) is an equipment that you would typically find in a lab – an engineering lab, a biomechanics lab, gait analysis lab, ergonomics lab.. you get the idea. They are great for measuring forces applied directly onto its surface. So when a force platform is placed on the ground, you could step on it to find out how much force you are exerting on the platform. For those platforms that measure multiple axes, you could also slide an object across the platform to measure resistance forces between the surfaces. In sports engineering, FPs enable studies in walking/running gait, jumping (and landing), friction measurements in water polo balls or shoes or gloves, the coefficient of restitution of balls, aerodynamic drag (when placed in a wind tunnel), and more.


An example of a Kistler Force Platform (blue) set up in a wind tunnel

For anyone keen to explore what else is done with force platforms in sports engineering, feel free to do a quick search on these journals: Sports Engineering JournalSports Technology Journal or Journal of Sports Engineering & Technology.

Inside Force Platforms

The majority of Force Platforms in the market are set up with multiple Strain gauges or Piezoelectric sensors/elements that deform proportionally to the applied load. There is also the not so common Hall Effect sensing Force Platform which doesn’t require an external signal amplifier/conditioner like the strain gauges and piezoelectric sensors do. They are typically quite expensive and their prices vary with the number of sensors, size, construction, and additional data acquisition (or signal amplifier) systems.

For those who can’t afford the expensive systems and is adventurous enough to try and build something, a sports physics researcher from the University of Sydney wrote a paper providing details of a cheaper home made force plate. Essentially he used Piezos that were manufactured for sonar applications and they cost $25 each. A quick search on Instructables also showed one DIY instruction on making a strain gage force plate. For the slightly less adventurous, there is also the option of the Wii Balance Board as a cheap force plate alternative. There have been some validations of the gaming platform as a standing balance assessment tool, a golf swing analysis tool, and for use in other medical applications. The only downsides of the Wii Balance Board are the user weight limitation and that a custom software is required to access and read the data.

Pressure sensors

There are three main differences between Pressure sensors and Force platforms. Pressure sensors are typically flexible and can be placed on flat or curved surfaces, unlike Force platforms that have to be mounted rigidly. The other difference is pressure sensors do not measure force vectors. Thirdly (or a slight extension of the second), Pressure sensors only quantify pressure that is perpendicular to it (single axis) so it cannot determine shear forces or friction between two surfaces. Due to their flexibility, pressure sensors have been used to determine comfort and fit in aircraft seats for Paralympians, analyse medical mattresses, measure the pressure of grip during a golf swing, pressure distribution on bicycle handlebars, and more.


Single force sensitive resistor (FSR) from interlink electronics

Pressure sensors are mostly made out of either resistive sensors or capacitive sensors. The main differences between them are the sensing material used and their electrodes. They can be constructed as single sensing nodes or they can also be constructed in a row-column array fashion. The advantage of the array or matrix construction (over single nodes) is that it requires fewer connections. In an array, the intersection between each row and column is a sensing node. So a 3 by 3 array creates 9 sensing nodes while only needing 6 connections.  On the other hand, 9 single sensing nodes will need 9+1 connections where the +1 is the common ground. The difference becomes much bigger as the number of sensing nodes increases (For example 100 sensing nodes can be achieved using a 10 by 10 array that needs 20 connections or 100 single sensing nodes that need 101 connections).

Single Sensor Nodes Vs Arrays 2

A simple illustration of Single sensing node Vs Sensor Matrix/Array

However, the matrix construction is not without its challenges. The matrix sensor circuit is prone to parasitic crosstalk (capacitive or resistive). This means when pressure is applied on one node or multiple nodes, the electrical readings for other (unactivated) nodes might be affected. This is also known as “ghosting”. Unless some correction is applied, the measurements/readings become inaccurate and potentially useless. Also, the bigger the matrix, the more complex the correction. But if accurate absolute readings are not required, then it’s fine.

A related side story

I have been following the development of this smart yoga mat that was successfully crowdfunded on Indiegogo back in Dec 2014. Fast forward to 2017, they are still struggling to deliver the product. Looking through their updates, we can see they had to deal with sensor accuracy (possibly the crosstalk or ghosting issue); and on top that, some other issues they had include sensor durability, mat materials suitability, and accuracy of their tracking algorithms (which they are using some form of AI). Having prototyped a smart exercise mat around the same time they started, I can fully understand the challenges and why it is taking that long. Then again I am not sure it is worth all that effort. Personally, I think that simply relying on a pressure sensing mat to monitor and give (technique) feedback on yoga poses (or any exercises) has its limitations. Adding camera tracking (possibly utilising the camera on the tablet) might help. That saying, it is not stopping others from developing similar products as seen in this video.

Smart Insoles

Smart Insoles or Instrumented Insoles are essentially pressure sensors made in the shape of a shoe sole. The sensors are usually made in a similar fashion described earlier. Most of the Smart Insoles are also built with IMUs so that it adds a bit more context to the pressure data such as whether the wearers are standing, walking, running or jumping. The greatest advantage of Smart Insoles is they allow feet pressure mapping and measurement on-the-go. Things like continual gait analysis and activity monitoring, and it even has medical application likes foot ulcer prevention and falls prevention.



There are a couple of shoemakers that designed their shoes with the Smart Insole embedded within the shoe like the Altra IQ for running and the Iofit for tracking golf swing stance. The good thing about them is they have designed everything to fit properly into a shoe, made for a specific function. So users don’t run the risk of their Smart Insole not fitting properly into their shoes and collecting inaccurate measurements. On the other hand, users are restricted with specific shoes for pressure monitoring or activity analysis.  But at the end of the day, the pros and cons are really dependent on the individual.

Brief Summary

Going back to the question: “Do Force Platforms, Pressure Sensors and Smart Insoles do the same thing?”; there are some things that they are all capable of performing (e.g. gait analysis), but they all do it in a different way.  Also, there are certain measurements or monitoring that are unique for each sensor. Here’s a simple table that sums it up:

Sensors Measures shear force Measures Pressure Doesn’t require rigid mounting Portable Tracks Motion
Force Plates X X ✔/X
Pressure Sensors X ✔/X X
Smart Insoles X

More about Smart Insoles

Personally, I feel that Smart Insoles is a great idea, with many useful applications in sports and health. Over the last few years, there has been an increase in research and development in this area with many patents generated in the process; and companies around the world have come up with commercial products around the concept of Smart Insoles. It is definitely still in its early stages and I am not sure if it has even reached Early Adopters yet. Sadly, one company that I followed (Kinematix) has already closed shop due to a lack of funding. Perhaps it is ahead of its time like the adidas intelligent running shoe with intelligent active cushioning. Nevertheless, I believe the potential (of Smart Insoles) is there and I think targeting specific niches/problems will probably have a better outcome than designing for a generic application.

If you have an idea or project needing a smart insole or custom pressure sensor, feel free to contact us or leave a comment. We might be able to help you with it or at least point you in the right direction. As always, thanks for reading!

This post also appears on link.

Other related articles:

The challenges of making Smart Sports Garments

What is a Smart sports garment?

Smart sports garments or smart performance garments is a relatively new product segment in the consumer sports tech market. There are probably different views of what the definition should be, but for the purpose of this post, it is a sports garment with embedded sensors/electronics. The main functions of sports garments include providing covering, protection, comfort, ease of movement and some might say making the athlete more aesthetically pleasing. Then with the added sensors and electronics, there generally are two different types of secondary functions.

The more common one is the passive function where sensors monitor stuff on an athlete, either physiological measurements or physical movements. It can make smart evaluations based on the data and give real-time feedback suggesting to the athlete that they should push harder or rest or correct their technique etc. But the decision to act on that suggestion still lies with the athlete or coach. There is also the not-so-common active function where the garment does something to the user. For example giving electrical muscle stimulations (EMS) or possibly electric shocks. But so far the “electric shock” feature is only found on a wristband and hasn’t extended to any other wearables yet. I am not sure why that is the case. For EMS, it has been said that it helps with muscle strengthening which is good for rehab or as a complementary training tool. But I will not go into it since it’s beyond my area of expertise.

R&D in Melbourne

A while ago, I had the opportunity to be a lab rat for a mate’s PhD thesis. He has developed a patented novel technology to measure muscle activity and hopefully able to predict the risk of muscle and knee injuries in elite athletes. The experiment I took part in was basically collecting a bunch of data from this novel sensing technology, wireless electromyography (EMG) sensors, a motion capture system, and a bike trainer. Unfortunately, it also involved me pedalling for my life.

How is this relevant to smart garments? Well, the novel sensors and EMG sensors were all hidden under a compression garment with motion capture markers secured on the outside. The compression tights ensure that the sensors remain where they are (and reliably capture data) and they also (coincidentally) facilitate motion capture. Albeit it was a very crude way of combining the sensors and the 2XU tights, it was a functional prototype (of sorts), and the ultimate goal would be to have those novel sensors built into compression tights.


Lab rat in action

As we discussed further on commercialising this novel sensing technology for smart sports garments or developing smart compression garments with any wireless sensors, it became apparent that there are a number of challenges. Here’s just a few:

Washing and durability :: A sports garment is going to get sweaty and smelly a lot more than everyday garments. So it definitely needs to get washed. Most smart garments in the market have an electronics module (IMU, BLE module, battery etc) that is removable because they will not survive a tumble in the washing machine. However, there are still conductive pads or conductive yarns (for electrical connections). Would long term washing affect their conductivity and so usefulness?  (A research has shown that most conductive threads will be affected although some hold up better.)

Sensor data accuracy :: In order to capture accurate & robust data, the sensors have to be positioned in the correct location each and every time the smart garment is put on. For measuring stuff like heart rate or EMG, it needs to maintain skin contact for proper measurements. If sensor positions are off (by a bit too much) or skin contact is not maintained, the data collected becomes meaningless and cannot be compared with previous data sets. Not to mention the effect of sweat on EMG electrodes.

Custom fitting :: This relates closely to the above point. Most sports compression wear are made in standard sizes. Sometimes one might find their compression garment being a bit too long at the legs or too short for the arms or too tight around a joint and too loose at a certain spot. It’s fine on a regular compression garment. But when sensors come into play, especially when there is fabric type of sensors (that measures compression or stretch), perhaps a custom-fit garment could be a more optimal solution.

Application :: This is possibly the most important challenge – designing a smart sports garment that solves a real need. It could be a very niche area or a wide-spread problem. But the starting point would be talking to athletes, coaches and sports scientists, to identify where the need is or what needs to be tracked. Then the smart garment that is developed would be a solution and not just a cool piece of technology.

What’s in the marketplace

Having said that, over the last 4-5 years, more than a handful of companies have taken up these challenges and developed their own smart sports garments. A quick search on google shows that there are at least 5-6 smart sports garments in the market.

Brands / Companies
Measured parameters
Heart rate Breathing frequency EMG Motion 3D motion (joints)

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OmSignal and Hexoskin have smart garments that are an extension of heart rate monitors with an added IMU (Inertia measurement unit) which provides parameters such as breathing rhythm, running cadence, step count and more. While they both seem to be generic fitness trackers when they first came out, it looks like Omsignal has now dropped their original Omshirt and focused on a women-specific product (the Ombra) for running. This might have to do with a review like this: link.

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Myontec and Athos are smart compression garments with surface EMG sensors. The point of putting on these garments is for the user to know what’s going on with specific muscle groups during their run, cycle or gym workout. Myontec is focused on the lower body (quadriceps and hamstring) with an emphasis on running and biking, while Athos covers the whole body looking at general strength training. It is cool that their accompanying software/app provides feedback of which muscles should be activated more during a squat (or other exercises) but I think it might be better if they could correct a user’s posture/technique that is causing the wrong muscles to be activated.


Heddoko is a full body compression suit that measures a user’s 3D motion much like the Xsens suit. The difference is that the Heddoko suit uses less number of IMU and has embedded stretch sensors, which makes it unique. Assuming the measurements are accurate and repeatable, it has lots of potential applications in sports biomechanics and injury prevention. But based on this video, they are still validating their sensors and trying to work out specific applications.

Some additional thoughts

On one hand, it is cool that there is all these performance tracking technology available to the average athlete – such as wireless EMG and 3D motion analysis (again, assuming the measurements are robust). On the other hand, I wonder if the benefits would outweigh the costs because they are mostly quite expensive and I am not sure if the average gym goer would need that much information about their workout. Perhaps they would be more useful to elite or professional athletes, especially where professional teams have coaches and sports scientists to analyse the data, and give custom feedback. They could also couple it with video playback and analysis so that there is more context to the data.

I think for the average athlete, a smart garment might be useful if they are going through physical rehab and need to monitor certain movements or muscle groups while under the guidance of a physical therapist. Or if they are trying to pick up a specific skill like throwing a football or baseball (In fact, there are sensor embedded sleeves that do just that, which I might discuss another time). Basically, there should really be a specific ‘pain’ to solve. A smart garment with a generic health and fitness application is probably not going to be of much use. Wristbands and smart watches already try to do that.

Do you already own a smart sports garment or are thinking of getting one? If yes, do leave a comment. I would love to hear your thoughts and what you would use it for. Thanks for reading!

Tracking & Managing Anxiety in Athletes

The 2016 Rio Olympic games as with the previous games was a great platform for many tech companies to showcase their latest developments. There are radar and camera technologies that capture motion/biomechanics of an athlete on the field and in the pool. There are wearable devices that (also) track motion plus monitor physiological parameters 24/7. They aim to positively alter athlete behaviour and optimise performance. There are also sports apparel and equipment that were designed and developed (after much R&D) to enhance athlete performance. But we will leave that for another time.

Wearables for tracking performance

Going back to wearables and tracking systems; they often look at (somewhat) straightforward parameters – joint positions, speed (or velocity), height, acceleration, impact, angles, rotation rate, heart rate, heart rate variability, sleep and other physiological stuff. Sometimes coaches and athletes only need to look at a single parameter while other times they may need to examine a combination of variables and find correlations or visualise them over time to identify trends. Some companies go further by processing the above data and coming up with (trademarked) indexes such as Player-Load (Catapult), Windows of Trainability (Omegawave) and Recovery Score (Whoop). What they are trying to achieve is break down all the data that is being collected and deliver one metric that simplifies things and make it easy for coaches and athletes to measure performance (and recovery) .

In major games like the Olympics, where athletes trained years to prepare and qualify for that one event and possibly one moment, there can be a lot of anxiety and pressure to perform. Even if all the physical preparation has been done right, the results could still boil down to how well those emotions are managed; the difference could be between a podium finish or not performing as well as expected. So are there wearable technologies that monitor an athlete’s emotions and maybe warn the athlete of dangerous anxiety levels that can lead to choking or panic?

Wearables for tracking anxiety

Turns out there are a number of wearables in the market that do that. Here are three different types:

  1. Head-worn wearables that measure EEG signals (or brain activity) like the Emotive Insight and Muse. Although the Muse is designed as an aid for meditation and relaxation, it is basically monitoring four EEG channels to see how excited or relaxed a person’s brain is. The Emotive Insight has five EEG channels and looks at the user’s cognitive performance in areas such as Engagement, Focus, Interest, Relaxation, Stress, and Excitement. Emotive also has a higher spec neuroheadset that can look at fourteen EEG channels and goes into much more depth of what’s going on in a person’s mind and how he/she is feeling.


    Emotiv Epoc+: 14 channel wireless EEG system

  2. Wrist-worn devices that measure electrodermal activity (or EDA), blood volume pulse, skin temperature and motion; like the Feel and Empatica E4 wristbands. Based on research, measurements of EDA strongly reflect sympathetic activation which is linked to stress levels and excitement. Measuring heart rate variability through the blood volume pulse sensor also reflects sympathetic and parasympathetic activation. Skin temperature is another reliable measure of stress levels as shown in this research. Finally, motion tracking with inertial measurement units (or IMUs) helps identify the user’s activity and tries to place a connection between anxiety levels and what the user might be doing at that time.



    Screen Shot 2016-08-30 at 10.19.16 AM

    The Empatica E4 and Feel: 4 sensors packed on a wrist device



  3. Clipped-on devices that measure breathing frequency like the Spire. The Spire is built with force sensors; when it is secured onto the user’s waistband or bra, it detects the expansion/contraction of the user’s torso and diaphragm during breathing, thus deriving the breathing rate. Then algorithms are used to determine from the breathing waveforms whether the user is calm, tensed or focused.


Screen Shot 2016-08-30 at 12.30.42 PM

Spire: Breathing frequency tracker


Most of these devices also provide an accompanying app to monitor anxiety levels, and they prompt users to meditate or do breathing exercises. On a side note, a breathing exercise for lung patients was adapted for training athletes’ breathing technique and also focuses on dealing with anxiety. Athletes could also listen to music that either helps them relax or stay focused. In a way, managing stress levels on a day-to-day basis can be beneficial for athletes because stress levels can increase the likelihood of an athlete falling sick or getting injured, and it also affects recovery.

Emotion Profiling for Performance

On the other hand, when it comes to performing well during competitions/races, some athletes actually perform better with some amount of anxiety. In fact, different athletes in different sports may perform better at varying levels of anxiety. In other words, some athletes perform well at high levels of arousal while others may perform better at lower levels of anxiety. It’s all about finding a sweet spot. As mentioned in this article, one widely used tool by coaches/athletes to identify that sweet spot or optimal performance zone is the individual zones of optimal functioning (IZOF) model. This is a qualitative analysis approach that involves the athlete recounting the emotional experiences related to successful and/or poor performances. All the emotions are then labelled and rated as described here, and this creates an individualised emotion profile showing which emotions are helpful for performance and which ones are unhelpful. Of course, this would only work if athletes have competed for a number of times previously and came out with different outcomes (winning or losing or setting new personal bests).


Individualised emotion profiling (source: sportlyzer)

Ultimately we could utilise all the different wearables (and tools) mentioned above and somehow piece all that data together to shed some light on the inner workings of each individual athlete. Then the data could be used to “pivot” them in the optimal direction. But at the end of the day, its really down to the athletes themselves pushing hard every day and fighting battles with their body, mind and soul to get to where they would be. So let’s just salute the Olympic athletes for what they do and what they have achieved. And while we await the start of the Paralympics, I leave you with this video below by Under Armour and Michael Phelps. Thanks for reading!

Dealing with the Heat

A while back, I wrote a post about overheating in the iPad – how too much heat renders the iPad useless because it just shuts down. When that happens, you could either remove the iPad from an external heat source (e.g. direct sunlight), allowing it to cool passively; or apply some form of active cooling to it (chemically, mechanically, or electronically). Then once the internal temperature has dropped below the “shut-down threshold”, the iPad usually performs normally again.

Athletes can also suffer from an ‘overheating’ type of situation and in some cases can lead to hyperthermia. Due to an extended period of high intensity physical exertion, and/or being in hot and humid conditions, an athlete’s core body temperature could go up to say 40 degrees C. Lots of studies have shown that this (excessive heat) can have a negative impact on the athletes’ exercise performance (or muscular endurance) and possibly some adverse effects on certain cognitive abilities.

So how do we deal with this heating issue that affects athletic performance? On top of ensuring proper hydration and sticking to safety guidelines (mostly common sense), there are a number of cooling strategies and technologies that could keep athletes cool, which then prevents heat illnesses, and ultimately helps maintain performance.

Heat Acclimatisation

Although not exactly a cooling strategy, heat acclimatisation is a common practice for athletes living in cooler climates and preparing to compete in warmer and humid climates. The acclimatisation process might involve moving to another location with similar weather to live and train, or it could be training in an indoor controlled environment where heating and humidifiers are applied. Basically, the aim is to get the athletes accustomed to the higher air temperatures and so reduce the impact of heat on their performance. In some cases, heat chambers are also designed to be hypoxic chambers so athletes can also be conditioned for high altitudes (which would be handy for events like the 2010 football World Cup).

An example of PAFC players training in a heat chamber in UniSA (source:

Cooling Strategies 

Pre-cooling is the process of cooling athletes before performing any exercise. There is evidence to show that pre-cooling procedures benefits athletes in endurance sports, and to some extent athletes in team-sports that require high-intensity repeated sprints (study link). It was gathered from this article that whole body pre-cooling is the more effective cooling procedure compared to only upper body cooling using cooling vests such as the adidas adipower or game ready vests. Although logistically, preparing the equipment for whole body cooling may take a bit more effort, compared to just distributing a bunch of cooling vests to the athletes.

An Example of a Portable Ice Bath from icoolsport

This article looked at a half-time cooling strategy that involves getting the soccer players to immerse their forearms and hands in 12 degrees water and putting a cold wet towel (that was previously soaked in 5 degrees water) around their neck. Their results showed that this primitive active cooling method significantly reduced the athletes’ body core temperature in 15 minutes.

A Novel Cooling Tech

A company called Avacore Technologies developed a novel technology that allows an athlete to cool down by simply wearing a specialised glove. How it works relies on the fact that the palm of our hands are radiator surfaces; which means when our body temperature goes up, blood flow naturally increases through those (radiator) skin regions to dissipate heat. This is achieved through special blood vessels called arteriovenous anastomoses or AVAs.


Retia Venosa

The glove system known as Rapid Thermal Exchange (RTX)  was invented by two Stanford biologists who were doing research on thermal-regulation. The system not only regulates a continuous flow of cool water through a pad (or grip/cone) which the user’s palm maintains contact with, it also creates a slight vacuum within the glove and that limits the blood vessels from constricting, which allows better blood flow and ultimately better cooling. There is a lot more explanation on their FAQ page, and links to scientific studies/evidence at the bottom of the page here. Or if you prefer to watch a video, check out this one from CNET where the presenter actually did a test herself and showed that it actually works – cooling her significantly and improving her endurance.

[A side note on the video: using an ingestible temperature sensor would have saved the presenter from that gagging experience (around 1:40 of the video)]

So not only is this glove technology keeping athletes cool and preventing diminished performance, coaches are seeing their athletes push harder and longer when the RTX is used in between training sets. The rates in gain is so dramatic that the gloves have been labelled as more effective than steroids. But even with such good reports, not everyone is rushing to purchase these gloves yet. As mentioned in their paper, the inventors recognised that there are a few barriers and one of it is people’s resistance to new views. Another challenge is to develop something more compact or even wearable, so that it increases the potential of effective application in other areas such as mining, firefighting, or emergency services.

Recently, Avacore launched an Indiegogo campaign to crowdfund their new consumer version which is just one standalone portable device instead of a few components. Looking at the number of backers, I would say it was very well received.


Different versions of the Avacore Cooling “Glove” (

Something for the makers and tinkers

Interestingly, someone who really liked the product but thought that the CoreControl Pro version was too expensive, decided to make a DIY version for a fraction of the price. He even made a CoreControl DIY Instructable. Based on the comments, there’s at least 2 other people who followed the instructions and built one for themselves. One other guy even made some improvements and published his own guide on how to build it.

Closer to home, a mate of mine also attempted to develop a product similar to Avacore’s hand cooling concept. One main difference is that his design does not require the use of ice and water, something that most of the methods mentioned earlier use. Instead, his entire system is electromechanical, very portable and can be easily switched between cooling or heating. If anyone in Melbourne would like to be one of the first few to trial his prototype, drop me a message/comment and I could help organise something.

Finally, with all the cooling technologies and methods out there for athletes, I think something that will really complement them, is a wearable temperature sensor (such as the cosinuss) that can constantly monitor body core temperature. That way, coaches can know exactly when to stop the athletes from their activity and stick their hand into a body cooling glove.



Safety Technology in Sports

Safety Technology Shit Accidents happen. Nobody plans for them to happen. But they do. The thought of “what if…” can be quite frightening, especially for people with some form of anxiety disorder. So if you are going for an overseas holiday, you might take up a travel insurance; if you are a school teacher bringing kids out for an excursion, you might prepare a risk management plan before that; and if you are organising a football competition, you will want to ensure that you got first aiders or sports trainers during the game. For protection, athletes wear safety equipment such as helmets, mouth guards, body armour, braces, goggles, gloves etc to reduce the risk of injury and possibly death. But if one considers the theory of risk homeostasis, athletes may go harder or play with less caution because of the protective gear and thus negates the effect. Lately engineers/designers/innovators have resorted to using various sensor and wireless technologies to help manage or prevent serious injuries in sport. We will have a look at a couple of these technologies that have been developed.

Managing concussions


Riddell’s built-in sensors

Wearing helmets are only good for protecting against skull fractures but not brain concussions. The next best thing to do is to measure the amount of impact and deduce if that might cause a concussion. The first helmet with a comprehensive impact detection system was Riddell. The Riddell HITS technology helmet is embedded with multiple sensors that measure the magnitude and direction of impacts to a player’s head. The impact data is transmitted wirelessly to a computer at the bench where it is analysed to determine the likelihood that the player has a concussion. This helps coaches and medical staff decide whether or not to take a player out of a game or the next few games.

After Riddell, a couple other companies like Brain sentry and Shockbox came up with (cheaper and) more versatile solutions. Basically, they developed wireless sensor devices that can be mounted on your own sports helmet (whether it’s Gridiron, Hockey, Lacrosse, Snow sports etc). The Brain sentry sensor works by flashing a red light when an impact over a certain threshold is detected, and that is an indication that the player should get some medical attention – a simple and straightforward system. The Shockbox sensor sends out impact data directly to the coach’s smart phone via bluetooth and the smart phone app allows the coach to monitor all the athletes at once for dangerous hits. How do they decide what amount of ‘g’ is too much? Well research by Greenwald et al and Broglio et al showed that most concussions happen between 70-100g, so any impact above 70g => possible concussion. HelmetSensors There are a  few other head impact sensors that work on a similar concept but worn slightly differently (on/in the head). The i1 Biometrics Impact Intelligence System is a mouthguard with built-in sensors, while the Impact Indicator 2.0 is a chin strap also designed with sensors that measures high accelerations. One thing worthy to note about the i1 Biometrics mouthguard is their shock absorbing material Vistamaxx that is also customisable to every athlete’s mouth.

ImpactDetection2If you google “head concussion sensors”, you will find a few other similar products that is entering the market soon. The bottom line is, they all identify impacts that are over the “safe threshold” and athletes can be kept (safe) on the bench instead of getting a second hit which could be deadly. But to really know if an athlete had a concussion, they still need to have a CT scan or use this electromagnetic coil that is a cheap substitute.

Preventing drowning

There is a shocking number of people who die or become permanently disabled because of drowning. Even with lifeguards or in cases where children are playing in the water with adult supervision, drowning could still happen. That’s because it only takes 20 seconds for a child to drown underwater unnoticed and 1 minute for an adult. Which brings forth the need for drowning prevention technology.

Aqauatic Safety Concepts LLC patented an Electronic swimmer monitoring system that consist of wearable sensors (worn on swimmers) that measures time of submersion and a monitoring system  at the pool or lake that detects drowning risks and alerts the lifeguards on duty.


The wearable sensor can be worn as a headband or attached to a swimmer’s goggles or swimming cap. The sensors send out a distress signal when submersion is past a safety limit, the signal is picked up by highly sensitive Hydrophone Receivers mounted in the lake or pool which then translates to an audio and visual alarm on land alerting lifeguards or  pool supervisors. In lakes or ponds where the water is not clear, a mobile receiver or Swimmer Locator can be used by the lifeguard to quickly find the distressed swimmer. A Control Tablet can also be used by the lifeguard to monitor status of swimmers in the facility.

But for folks who have a small home pool and don’t need such an elaborate system, there are a couple of choices for small portable systems, like the Safety Turtle and the SEAL Swim Safe. Both work on a rather similar concept: swimmer wears a wearable sensor that detects submersion and is monitored by a portable base station that runs on batteries.They both also use names of sea animals! Apart from that, they are actually quite different with two main differences:

  1. The Safety Turtle sensor is a wearable wrist band whereas the SEAL is a wearable neck band.
  2. Safety Turtle developed separate systems/devices for adults and pets; while the SEAL designed four different safety levels on the band, starting from an immersion alarm for the non-swimmer to a more complex triggering mechanism/algorithm for safeguarding elite swimmers.

DrowningDetectionTechWhen asked why the neck band design was used for the SEAL (which on first glance appears to be an awkward swimming accessory), the CEO and Co-inventor, Dr Graham Snyder said the sensor/antenna had to be in close proximity of the nose and mouth for the detection to be accurate; and tests with swimmers confirmed that having it at their neck was not as noticeable as they thought nor did it restrict swimming.

In fact, because the SEAL was designed to be used by swimmers of different abilities, one of the biggest challenge the developers had was preventing false alarms in every safety level and making sure that drowning detection is highly accurate and timely. Going forward, the team that brought out SEAL is also planning to add other features including GPS, two way communication and monitoring physiological parameters.

Even with all these terrific wireless sensor technologies developed for keeping sports safe,   the most critical component is still human intervention – coaches and medical staff to identify a possible concussion, and vigilant lifeguards and parents to note dangers and distress in swimmers. Without them those technology will just be another piece of accessory.

Thanks for reading and stay safe!

Wireless Power Technology and its application in Sports & Health

Tesla with his "Magnifying transmitter"

Tesla with his “Magnifying transmitter”

Wireless power isn’t an entirely new concept. The first person who tried to do it was none other than Nikola Tesla, and that was back in 1890s. Today, more than 100 years later, it is a reality.

I first saw it work on this Ted Talk by Eric Giler back in August 2009. He demonstrated a version of it that was developed in MIT between 2005 to 2007 and led to a spin-off company, WiTricity. Other than WiTricity, there are a couple of companies or organisations that developed versions of wireless power including: WiPowerPowerbyProxiQi (pronounced “Chee”) and the Alliance for Wireless Power (A4WP). Their technology are all largely based on electromagnetic induction principles, although WiTricity and PowerbyProxi are a bit more distinct in their technology and both have Intellectual Property. WiTricity uses magnetically coupled resonance, it does not depend on line of sight, and it covers a distance up to several meters. On the other hand, PowerbyProxi developed something they call Dynamic Harmonization Control which they claim to be the most efficient wireless power transmission and they also developed a wirelessly rechargeable double-A battery!

Although the most common application in the market now is charging mobile electronic devices (smart phones, media players, tablets or laptops), the real potential for wireless power transfer is huge. Since this is a sports & health technology blog, let’s look in those areas:

Firstly in the medical field, implantable medical devices like artificial (permanent) pacemakers will no longer need to be replaced when the batteries lose power, which means less surgeries required, less time spent on post-op recover and rehabilitation and also brings new meaning to “permanent pacemakers”; and not just pacemakers, lots of other implantable medical devices could take advantage of wireless power – ventricular assist devices, swallowable endoscopes, deep brain neurostimulators, cochlear implants, foot drop implants, gastric stimulators etc. In case you were wondering about the risks of wirelessly powering devices in the human body, engineers in Stanford have already proven it is safe and effective.

In sports engineering, wearable inertia sensors tracks and measures movements of athletes in the field using GPS, accelerometers, gyroscopes and magnetometers; with improved wireless tracking (indoor and outdoor) and increased data storage capabilities, the athletes can be monitored for as long as the devices’ battery has power. But if a stadium or a field or an indoor court can have wireless power, that limitation is gone, the sensors would be powered right in the field while being worn on the athletes. Also, this technology would enable sensors to be embedded into sports equipment permanently – solves the problem of designing an outlet for charging while keeping it water resistant. It could be balls, rackets, surfboards, snowboards, paddles, bicycle helmets, shoes, the list goes on. In fact, 94Fifty has already pushed this wireless power technology into their instrumented basketball using the Qi Specifications. You can read more in their Kickstarter  funding page here.


Instrumented basketball with wireless charging

Personally, what I think will be perfect is if we could combine an electricity generating equipment like the Soccket with wireless power transfer. So imagine running shoes generating electricity as you run and that is transferred wirelessly to power your heart rate monitor and GPS watch and MP3 player. That would be awesome.

Anyway. For developers who would like to incorporate wireless power into their products, just check out any of the companies or organisations mentioned above to find out about their licensing options or standards for wireless transmitters and receivers; and may the force (wireless) power be with you!

Thanks for reading!

Wearable activity trackers

Wearable TechJust a few months back, Dan got himself the Fitbit Ultra, that tracked how many steps he did, and from I can see on the product website, it also tracks distance, sleep, calories burned, allows you to log your food intake, and since then they also added a new feature that tracks stairs climbing. Its like a supercharged pedometer.

Now other than Fitbit, many other sports, health and start-up companies have recently jumped onto the bandwagon of making Wearable Activity Trackers (WAT). Not just tracking sports activities like running or cycling where you use GPS to track your location, speed and altitude; but activity in general. Its almost like writing your diary or journal at the end of each day, and recording every single (physical) activity you did, minus the emotions; and the main motivation for using these devices: to lose weight, keep fit and stay healthy. Since I am not having any other projects on hand at the moment, I decided to do a bit of investigation, online. I’m sure the list is not exhaustive but these are the more popular ones that are in the market (or coming soon into the market):-  Nike+ Fuel band, Jawbone Up, LarkBasis, BodyMedia Fit, Sqord Powerband, Fitbit, & Misfit Shine.

Wristworn activity trackingSo these WAT typically have three common features:

  1. They are wearable (obviously),
  2. They have sensor/s on them, and
  3. They have processors with some smart algorithm that makes sense out of the sensor data.

Activity trackers clip on 2Wearable/Design. In terms of being wearable, they can either be worn on your wrist, which seems to be the most common, or worn like an armband or clipped on your clothing or shoes or bike. Some of them display figures and stats while some just have little LED lights that show how you are progressing on your activities. But all of them are designed to look aesthetically pleasing since it has to been worn on people during most of the waking hours.

Sensors/Trackers. How do they track or measure activities? Although not all companies provide that information, but logically these devices would have accelerometers built in to capture movement data – walking, running, jumping or sleeping. They possibly have GPS modules and Altimeters that give you location and altitude data. BodyMedia and Basis also monitors your perspiration, skin temperature and heart rate (only Basis), because you could be doing Yoga and even though there isn’t too much movement involved, it still works up a sweat.

Algorithms/Insights. But having all that raw data mentioned above can be a bit of a pain if it doesn’t mean anything. So they need some form of algorithm (decision or machine learning) that deciphers the data. Using the acceleration data (either single axis or resultant of three axes), counting steps could be as straightforward as counting the number of peaks from the acceleration signal. Estimating your stride length could give you distance which could also be verified with positioning data from GPS. If combined with an altimeter, it would be able to tell if you are climbing stairs or going uphill. Then the physiological data coupled with movement data probably provides input for calculating calories burned. The ‘tricky’ bit is identifying different physical activities. Lark can differentiate between walking and running, which is quite straightforward in my opinion (see figure below). Shine on the other hand, seems to be able to differentiate bike pedaling, swimming and running. That is quite intriguing and I am curious how they do it. A ‘smart’ way of doing it is to simply track all different activities using an overall activity score. Nike uses the NikeFuel, which they say is the universal metric of activity. If you check their website, it mentions a ‘sports-tested accelerometer‘, true story. I think they probably mean the accelerometer is suitable for measuring movements in sports.

Identifying running activity

Records. Anyway all that processed information is then stored in their own database system where you can review your activities last week or month or year (on your smart phone or computer) and get an idea of how well or poorly you have progressed in your quest for good health. Then lastly, to spur you on, there is the whole connection with social media and gamification that allows you to compare your performance with your friends or even some sports celebrity.

Is this effective? Well a study showed that among a group of overweight people, half of the group that used a tracking system lost more weight than the other half that didn’t. A guy who found out he had diabetes turned to using these devices and a host of other health monitoring equipment, and actually managed to ‘save’ himself after 6 months of activity tracking. So it works. Although there are some who think constant tracking isn’t really necessarily the best, and some who think there is still room for  improvement (maybe that’s why new gadgets keep appearing), such as making ALL the data interoperable and having a unified electronic health record.

So what next? For the sports nut or health conscious consumer, the bottom line is still: are you willing to pay around $150 – 200 to track your life? For the engineers or developers, if you see more opportunities in this area, some of these companies (like Shine) offer APIs for their devices, and Nike has even come up with a program to support companies who have interesting ideas on how to promote active living. Most importantly, you will get to work with the ‘sports-tested accelerometer‘! How cool is that? Maybe I should sign up for that…