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=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 [[Running Power Meters| power meter for runners]], which superficially sounds like a good idea. Certainly, there 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, as their website does not explain their approach or a well, nor do they seem to be any validation studies that I could find. 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. However, Stryd also claim to be accurate enough that no calibration is needed for their Footpod, which is intriguing. I will test Stryd shortly.
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 to potentially gather the metrics typically associated with a Footpod, plus have data from pressure sensors in the insoles. I've not tested the TUNE, but what I can gather suggests it provides less data than you might expect. There is obviously Cadence, and they have Ground Contact Time which is shown as Swing Time and Stance Time (these are just simple calculations from and GCT.) The only metrics from the insoles appears to be the percentage of footfalls that are heel strikes (Rear Foot Strike, RFS), and something called "Stance Dynamics." It's not entirely clear what "Stance Dynamics" is except for the text "the time in propulsion during the Stance Phase." This suggests that perhaps the insole can measure sharing forces to determine how much of the Ground Contact Time is spent with the foot pushing backwards to generate propulsion. Having one device for each foot provides some insight into your symmetry which is likely to be a significant factor in injuries, but obviously that's limited to the metrics that TUNE is gathering. It looks like TUNE will provide audio coaching, but 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 be adding and iWatch in the future, something I wish more running sensors would do. I'm not seeing enough data being gathered to make this device worthwhile. There are a couple of concerning caveats, the main one being that the TUNE is not waterproof. The other possible concern is that the insoles cannot be cut to size, but in practice these insoles go under your existing insoles rather than replacing them, so this might not be an issue. Overall, I'm a little underwhelmed by the amount of data that TUNE is providing, and I'm not planning on testing it at this point.[[File:KinematixTUNE.png|none|thumb|300px|The TUNE sensor.]]
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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 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.
* '''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]]''
The SHFT system uses two pods, one on the chest and one on the foot. 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]], but my testing suggests this is far from useful. The system requires you to carry your phone, and 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've found the SHFT metrics are not as accurate as I'd like; read more at [[SHFT]].
[[File:SHFT Pod.jpg|none|thumb|250px|The SHFT pod is delightfully rounded and rather organic.]]
=Sensoria=
''Main Article: [[Sensoria]]''
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=
=Testing Approach=
Where possible, I like to verify the metrics that these running sensors are providing. In some cases, this is a fairly trivial, such as [[Cadence]] which you can measure by simply counting your steps. Some other metrics I've verified by using High Speed Video (HSV.) This requires a little bit of time and effort, and a lot of attention to detail but it can be quite an effective approach.