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From Fellrnr.com, Running tips
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TUNE consists Kinematix went out of two insoles and attached pods, connected by a cable as shown business in the image belowApril 2017. This allows it =Testing Approach=Where possible, I like to potentially gather verify the metrics typically associated with that these running sensors are providing. In some cases, this is a Footpodfairly trivial, plus have data from pressure sensors in the insolessuch as [[Cadence]] which you can measure by simply counting your steps. Some other metrics I've not tested the TUNEverified by using High Speed Video (HSV.) This requires a little bit of time and effort, and a lot of attention to detail but what I it can gather suggests it provides less data than you might expectbe quite an effective approach. There is obviously Cadence, and they have * '''Ground Contact Time which is shown as Swing '''. I've used HSV to verify Ground Contact Time , and Stance found more variation than I expected. Using HSV to measure Ground Contact Time (these are just simple calculations from you can see the very earliest and GCT.) The only metrics latest stages of contact as well as estimating the pressure changes from the insoles appears to be compression of the foam midsole. Examining the percentage of footfalls video makes it clear that some devices are heel strikes (Rear Foot Strikeincluding time where the shoe is completely airborne, RFS), and something called "Stance Dynamicswhich is a little surprising. * '''Vertical Oscillation'''." ItI's not entirely clear what "Stance Dynamics" is except for ve evaluated the text "accuracy of Vertical Oscillation by looking at the time in propulsion during the Stance Phasemovement of my torso using HSV and lasers." This suggests that perhaps the insole can measure sharing forces proved to determine how much of be rather more tedious and time-consuming than I'd anticipated, but the Ground Contact Time is spent with the foot pushing backwards results were worthwhile (to generate propulsionme at least.) * '''Foot Strike'''. Having one device for each foot provides I've done some insight into your symmetry which is likely to be a significant factor simplistic testing of sensors that measure [[Foot Strike]]. I've run with these sensors in injuriesmy usual heel strike, but obviously thatplus running forefoot both with and without my heel touching down. I's limited ve used HSV to the metrics verify that TUNE my foot strike pattern is what I think it is gathering. It looks like TUNE will provide audio coaching, but as it's unclear if there will be any real-time audio feedback. They have created the option of sharing data with your coach, which is a nice option for those who work with a coach. Their website suggests that they might easy to be adding and iWatch in the future, something I wish more running sensors would domistaken. Ididn'm not seeing enough data being gathered t include midfoot strike as this is tricky to make this device worthwhile. There are a couple of concerning caveatsget exactly right, the main one being that the TUNE is not waterproofand tricky to verify using HSV. The other possible concern This approach to measuring Foot Strike is that based around the insoles cannot be cut to size, but in practice these insoles go under your existing insoles rather than replacing thempoint of first contact, so this might not be an issuethe point of highest force. OverallPersonally, I'm a little underwhelmed by believe that the amount of data that TUNE latter approach is providingfar more relevant, and Ibut harder to measure.* '''Power'''m not planning on testing it at this point.It's tricky to measure [[File:KinematixTUNE.pngRunning Power Meters|none|thumb|300px|The TUNE sensor.running power]]without access to VO<sub>2</sub> equipment, so I've resorted to some simple tests. An incremental treadmill test should show an increase in power with an increase in pace; if it doesn't pass that test, then it's probably not much use.
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[[File:Running Sensors.jpg|right|thumb|300px|A selection of the running sensors I've tested. From top left: [[Moxy]], [[BSX]], [[Wahoo TICKR Run]], [[Lumo Run]], [[TgForce]], Garmin [[Running Dynamics]], [[SHFT]], [[MilestonePod| MilestonePod v2]], [[MilestonePod| MilestonePod v3]], [[Stryd]], and a Gu for size comparison.]]There are a growing number of wearable devices that will analyze your biomechanics, mostly from small startup companies, though the bigger players are also contributing to the space. Many of these devices a making use of the cheap and accurate accelerometers that are now readily available, though there are some other approaches being used. These are cheap accelerometers have created an explosion of products, and it seems likely that we'll see a number of companies fail. Here are my sound bite summaries:* [[Stryd]] is a running sensors that I think every runner should have. It's the most accurate way of measuring distance and pace, and has integration with a wide array of running watches. Its estimate of [[Running Power Meters| "Running Power"]] is moderately useful.* Garmin's [[Running Dynamics]] is well worth having if you own a Garmin watch that support supports it, though I wouldn't buy a Garmin just for its support of Running Dynamics.
* [[RunScribe]] provides lots of detailed and useful information, but I consider it a 'running lab' rather than an everyday training tool.
* [[MilestonePod]] is amazingly cheap and provides a wealth of data. It's worth the cost just for its ability to track the miles you put on your shoe, but it adds in more data than most other systems that cost many times as much.
* [[Wahoo TICKR Run]] give gives some useful interesting metrics, but you have to use their Smartphone App to get them. Their "3D Smoothness" would be awesome if it worked. It's also a Heart Rate Monitor that supports both Ant+ and Bluetooth.
* [[Moxy]] can provide a new way of evaluating exercise intensity by looking at the oxygen saturation of the blood within the working muscles. However, not only is it expensive, but you'll also need to dedicate significant time and effort into getting the best out of it.
* [[TgForce]] is a "one trick pony", but it's a great trick. It measures the [[Impact]] on the lower leg rather than the foot, providing great real time metrics. Sadly , there are production issues at the moment that are causing the sensors to fail.
* [[Moov Now]] This is a cheap and interesting sensor. Like the TgForce it can measure lower leg [[Impact]], but it's got software problems that have not been fixed.
* [[Lumo Run]] Needs more development before it's ready for prime time.
=What To Look For In A Running Sensor=
Having tested a fair number of running sensors, I think there are 3 aspects of the metrics that a sensor provides that you should consider.
* '''Accuracy'''. Not unreasonably, a running sensor should provide a reasonably accurate metric. Depending on the metric, the value could have some degree of error without affecting its value if the error is always proportional. For instance, if a sensor gives a value for Ground Contact Time that is always 10% too high, that may be perfectly acceptable as you can look for relative changes. Or a sensor could have a synthetic value of "smoothness", which might not be based on a real-world measurement, but could still provide actionable information. Of course, accuracy is always preferable, and an inaccurate sensor could cause more problems than it solves. A Cadence sensor that reads 10% too high might lead you to believe that your Cadence is fine when it's actually far too low.
* '''Responsive'''. A useful metric needs to be responsive enough that you can see the results of any changes to your running form. A metric that has too much smoothing can be quite frustrating, while one with too little smoothing can be so twitchy that it's equally useless. Of course, the responsiveness also depends on the feedback method, and a metric that you only get in post run analysis is far harder to use.
* '''Meaningful'''. A valuable metric is one that has some meaning to you as a runner, either because it has a bearing on your [[Running Economy]] or because it may have a bearing on your injury risk. The current state of the available research doesn't provide a huge amount of confidence linking many of the available metrics to either injury rates or Running Economy, but there are some that seem to have potential.
* '''Actionable'''. The final characteristic of a valuable metric is one that you have some control over. For instance, Cadence is relatively easy to change and therefore the metrics are actionable. Other metrics may be rather tricky to modify with your running form, such as a braking force (at least, I found it very hard to change that metric.) Another reason why a metric may not be actionable is because correlation is not causation. For instance, lower Ground Contact Time is associated with a better Running Economy, but it's not clear if reducing Ground Contact time will directly improve Running Economy, or if there is some other variable that is responsible. (My personal suspicion is that improvements in Running Economy are more related to Cadence, which in turn changes Ground Contact Time. I'd like to see research into Ground Contact Time normalize the values against Cadence.)
=Stryd=
''Main Article: [[Stryd]]''
The Stryd Footpod is my favorite running sensor. It provides vastly better distance and pace information than any GPS watch I've tested. This alone makes it well worth the purchase price and if for any reason I lost mine, I'd replace it immediately and without hesitation. Stryd is primarily marketed as a "running power meter", though I think this sells it a little short. [[Running Power Meters]] are somewhat flawed concept, as they are really an estimate of power, and the estimate is of far less value than a cycling of power meter is to a cyclist. That said, I found that Stryd provides a useful way of providing even effort on uphill sections (but not down hills.) It also has the best watch integration of any running sensor.
=Garmin's Running Dynamics=
''Main Article: [[Running Dynamics]]''
Many newer Garmin watches ([[Garmin 620| 620]], [[Garmin 920XT| 920XT]], [[Garmin Epix| Epix]], [[Garmin Fenix 3| Fenix 3]], etc.) combined with a special chest strap will provide extra metrics that can give insight into your Running Form. The Garmin watches will provide these metrics in real time, allowing you to see the effect of changes in your form. These metrics include:
* Vertical Oscillation. This is how much the torso moves up and down with each stride. It is generally believed that less [[Vertical Oscillation ]] is a better, but I suspect that this is an oversimplification. It's sometimes a thought that a greater vertical oscillation [[Vertical Oscillation]] will result in greater [[Impact]], but this is not the case. [[Impact]] is how quickly you decelerate, so landing hard can result in less vertical movement but a shorter, more intense deceleration. It's even suggested that greater vertical oscillation [[Vertical Oscillation]] will result in more braking force, but that does not seem reasonable. I believe that some are part of a runners vertical movement is likely to be elastic in nature (consider a bouncing rubber ball), some of the vertical motion will be while the runner is airborne (ballistic), and some of the vertical motion is the vertical deceleration as the runner lands. So it seems likely to me that excessive vertical oscillation [[Vertical Oscillation]] is bad, but it's a tricky to know what excessive is likely to be, or how to correct it.
* Ground Contact Time (GCT). [[The Science of Running Economy]] generally shows that longer Ground Contact Time is correlated with poorer [[Running Economy]].
* Ground Contact Time Balance. This is the relative Ground Contact Time ratio of the left and right feet, which will reveal potential imbalances in the body.
* Computed metrics. The Garmin watches will use the basic metrics to calculate things like stride length (based on cadence and pace), and Vertical Ratio (vertical oscillation [[Vertical Oscillation]] to stride length ratio).
[[File:RunningDynamics.jpg|none|thumb|300px|Garmin's Connect web site shows the metrics gathered using the HRM4 and [[Garmin Fenix 3]].]]
=RunScribe=
The [https://www.amazon.com/dp/B00KLAGSW8 Wahoo TICKR Run] is a chest strap based system that's similar to Garmin's [[Running Dynamics]]. It supports both Bluetooth and Ant+, which is nice, but most of the functionality beyond heart rate requires you to have your phone with you on your run. If you do, then you get Cadence, Ground Contact Time, Vertical osculation, and 3D smoothness. This 3D smoothness shows the jerk (rate of change of acceleration) in three planes; forward-backward, up-down, and side to side. This has great potential, but the smoothness depends far too much on the tightness of the strap, even varying with your breathing.
[[File:WahooSmoothness.png|none|thumb|250px|The smoothness that Wahoo displays seems like it could be really valuable if only it was usable.]]
=Lumo Body Tech Run(Bankrupt) =
''Main Article: [[Lumo Run]]''
'''Update: Lumo has gone bankrupt and as far as I can see their sensors are effectively bricked. Unlike BSX, who made some of their software open source, Lumo has just disappeared. '''Like many other devices, [[Lumo Run]] uses accelerometers to measure body movement, but uniquely (so far) Lumo places the accelerometers at the small of your back. This allows Lumo to not only detect [[Cadence]] and [[Vertical Oscillation]], but also breaking and pelvic movement. The measurement of braking force is rather different from [[RunScribe]], as Lumo measures how much your overall body slows up with each stride, rather than measuring the deceleration of your foot in touch down. I believe that both approaches are important, and give valuable insight into possible biomechanical problems. In addition, Lumo will measure how much your hips (pelvis) will drop from side to side, and how much it rotates (twists). Lumo is available Lumo Run is available for <jfs id="B01K22SOYE" noreferb="true"/>. I really wish that Lumo would measure [[Impact]], as it would be great to know how much of the foot strike [[Impact]] reaches the hips.
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=SHFT=
''Main Article: [[SHFT]]'' The SHFT system uses two pods, one on the chest and one on the foot, rather like the Zoi. The SHFT system includes some unusual metrics such as toe off angle and body angle, as well as Cadence, GCT, Vertical Osculation, [[Impact]], Braking, and Foot Strike. They also claim to measure [[Running Power Meters| power for running]], something I'd need to see demonstrated in a lab to believe it's accurate and even then I'm not sure it's but my testing suggests this is far from useful due to the impact of [[Running Economy]]. The system requires you to carry your phone, and you're the main feedback is via audio through the headphones which I generally find rather ineffective. There are some good post run analytics available via the app and on their web site, as well as data export of the basic running information. The price of the two SHFT sensors is $300 which is a little high compared with other systems, but it does provide quite a bit of information. I am currently testing 've found the SHFT.=Stryd=Power meters have helped cyclists for a number of years, providing a valuable metric around how hard the cyclist is exercising. Stryd is attempting to provide a power meter for runners, which superficially sounds like a good idea. Certainly, there metrics are many problems with using Heart Rate to determine training intensity, and measuring VO2 is only practical in a laboratory, so and a power meter could be a better option. However Stryd actually measures movement and then calculates power. The details are a little unclear, not as accurate as their website does not explain their approach or a well, nor do they seem to be any validation studies that I could find'd like; read more at [[SHFT]]. Stryd has changed from using a chest mounted sensor to a footpod, and it seems dubious that power can be calculated from foot movement alone[[File:SHFT Pod. However, Stryd also claim to be accurate enough that no calibration jpg|none|thumb|250px|The SHFT pod is needed for their Footpod, which is intriguing. I will test Stryd shortlydelightfully rounded and rather organic. ]]
=Sensoria=
''Main Article: [[Sensoria]]''
[[File:BSX1.jpg|none|thumb|x300px|The dashboard view of the BSX app, showing previous results.]]
=RUNTEQ Zoi=
Zoi places sensors on both the foot and the torso. This allows it to gain a little more insight than other sensors as it knows about the movement of the foot and the torso independently. Eventually I expect to see a company produce a group of sensors placed on each foot, each knee, and the pelvis, which would give insight into the movement and [[Impact]] forces across most of the body. The Zoi only has one Footpod, so it doesn't give you detailed foot strike information in the way that [[RunScribe]] can, though you could see them adding that functionality in the future. The Zoi gives quite a few metrics, including [[Cadence]], Ground Contact Time, [[Vertical Oscillation]], breaking (at the torso, not foot breaking), of [[Foot Strike]] type (fore, mid, heel), Foot [[Impact]], and some [[Pronation]] information. Zoi has a smartphone app that provides real time feedback and post-run analytics, but I've not seen any support for displaying metrics on a watch. Currently Zoi is on pre-order in Europe for 150 EUR. I'd like to test this system if I can get hold of one. The approach is similar to the SHFT system, though the SHFT uses a 9-axis sensor and it's not clear what the Zoi uses.
=RPM<sup>2</sup>=
RPM<sup>2</sup> (Remote Performance Measurement/Monitoring) is a pair of insoles that fit into your normal running shoes. These insoles measure pressure and use accelerometers to measure movement (a little like Sensoria). The details are not entirely clear from the web site, but they claim to measure [[Cadence]], Ground Contact Time, [[Foot Strike]], and "acceleration power". The system also claims to measure running power, though I'm not sure of the methodology. The RPM<sup>2</sup> system measure pressure in four areas (Sensoria has three), giving a [[Pronation]] measurement. There are notes that RPM<sup>2</sup> insoles are not waterproof, which is rather disconcerting, and if you run in different shaped shoes the fitment is likely to be problematic. The sizing of the insoles needs to take into account the position of the ball of the foot to ensure the sensor is in the right place. The system supports Bluetooth to connect to your phone as is common with running sensors. The RPM<sup>2</sup> can also connect to an Ant+ watch, though it's a bit of an ugly kludge. You need to have your phone with you, and then plug in the Wahoo Key adapter via a lightning-to-30 pin adapter to transmit Ant+ to a watch. The Wahoo Key and adapter are all extra bits you have to buy. The system can also be used as a power meter for cycling. Their web site is [https://www.rpm2.com Remote Performance Measurement/Monitoring].
=Kinematix TUNE=
=Ideas For The Future =
This section documents a few ideas I've had for running sensors, partly to inspire manufacturers, and partly to disclose these ideas so that they cannot be patented in the future.
==Proportional Audio Feedback ==
Many running sensors will provide information on your biomechanics using an audio message. Typically, this is a spoken message such as "you're landing on your heel" or "your braking is 1.31 feet per second." I generally find these audio messages far more annoying than they are useful. The messages tend to occur too infrequently for me to get a sense of how any modifications in my form are changing the metric being measured. The spoken word means it's a little tricky to combine this with music or radio. A better approach is to have a simple signal like a beep when your metric is outside the desired level. For example, [[TgForce]] will beep when your [[Impact]] is too high, and you can combine this simple audio signal with music for the spoken word from a in audiobook or the radio. I believe that a superior approach is to have a variable audio signal that indicates how well you're doing. So instead of having a simple threshold such as 7g you'd have a range such as 5-9g. Then, when your [[Impact]] is above the lower threshold you would get an audio signal, but the audio signal would vary in one or more of volume/pitch/duration depending on where you are in the range. So a 5g [[Impact]] would produce a quiet, short, deep beep, and 9G [[Impact]] would produce a loud, longer, high-pitched beep. This way you'd get quantitive feedback on how well you're doing against your chosen metric.
==Deriving Practial Practical Impact From Acceleration==
Often running sensors will provide a value for impact based on the acceleration measured at the foot or leg. However, the bulk of the stresses on the lower limbs comes from the acceleration of the overall body mass during landing. Therefore, I believe it would be more effective to measure the acceleration of the torso on landing to provide an estimate of the stresses on the lower limbs. I suspect that both peak acceleration and the area under the acceleration curve would provide insight into the stresses of running. Peak acceleration is fairly obvious, and I suspect is more useful than a jerk. However, it may be useful to evaluate the area under the acceleration curve, as the time spent under stress could also be a significant factor on injury rates.
==Measuring Foot Strike==Several running sensors will measure [[Foot Strike]], though so far, I've only found RunScribe and SHFT to provide useful data. However, even these devices tend to measure the foot angle on initial contact, and I suspect that it would be far more useful to measure foot and call at the time of maximum deceleration of the torso. This requires at least two sensors, one on the torso and another on the foot, and ideal three so there's one for each foot. Synchronizing the timing between the devices is likely to be problematic, but not insolvable.
