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From Fellrnr.com, Running tips
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{{DISPLAYTITLE:Sensoria Sensor Review}}The principle behind Sensoria is a cool one. They've created a stock that has built in pressure sensors underneath, and a small anklet that relays the pressure to a smart phone. This allows Sensoria to detect [[Foot Strike]] patterns with a potentially far more accuracy and an accelerometer-based system. In addition the anklet has accelerometers to measure Ground Contact Time and impact. If the sensors react fast enough, then the system could potentially detect rates of loading to see how hard the runner's landing. It's with these great expectations that I started my testing, performing a number of runs in different footwear and with different Foot Strike patterns, comparing the Sensoria against other [[Running Sensors]], including [[RunScribe]], the Garmin [[Running Dynamics]], [[MilestonePod]], and [[Moov Now]]. Sadly, my testing reveals that the system doesn't seem to work in the real world. I ordered a replacement system, but it has the same problems. Let me lay out the liturgy of problems:
* The biggest concern is that the system doesn't work, or at least, not reliably enough to be of any use. When I first put on the socks and anklet, the accompanying app would show in real time how much pressure was on each of the three sensors as a 'heat map' (see screen shot below). If I press my heel to the ground the heel area would light up, and if I press my forefoot to the ground the two forefoot sensors with light up on the app. This was both rather cool, and confirmation the system was working. Sadly, after only a few minutes of running the real-time display showed that the sensor was no longer responding. It's possible that this was due to sweat building up, but after only a few minutes this seems unreasonable. I contacted their support and described the problem, to which they responded with ''"During a long run the pressure sensor heat map and real-time visualization on your phone may be impacted by different environmental factors. However the real-time feedback algorithms and the web dashboard have been designed to provide you with accurate data." '' This does not seem reasonable or logical to me, but to give them the benefit of the doubt I did some further testing. <br/>[[File:Sensoria Heatmap.png|none|thumb|100px|The heat map of the Sensoria app.]]
* I tested the Sensoria with three different shoes (heavily cushioned, minimally cushioned, and nearly barefoot), and I tested each shoe with my normal rear foot landing, a forefoot only landing, and a forefoot first landing. My intended Foot Strike pattern was confirmed by [[RunScribe]]. You can read about the details of this testing below, but the bottom line is that the Sensoria didn't report my foot strike correctly. I think that this is a showstopper, but I'll continue to list the other issues. (I tested the Sensoria using both the left and the right sock, so I'm reasonably confident that the problem is not an isolated manufacturing issue.)
* The basic package only gives you one anklet, so you don't get any balance information, but you could buy a second anklet.
* The Sensoria requires you to run with your phone, which I think is a major annoyance. While many folks are happy doing this, I find a smart phone rather cumbersome and I'd much rather have the information displayed on the watch.
* In addition to the broken [[Foot Strike]] information, the Sensoria also gives Ground Contact Time and some impact information post-run. The impact is on a scale of 1 to 10, but is not in g's (gravities). The reported Ground Contact Time by Sensoria is quite a bit higher than any of it should be. (See Ground Contact Time testing below.)* Sensoria state that the other systemsanklet is "splashproof" and it should be fine in the rain. Personally, this would make me cautious about using it in heavy downpours.
=Gallery=
{| class="wikitable"
|}
=Test runs=
My first test consisted of nine runs; three with [[MinimaxMaximalist]] [[Hoka Clifton]]s, three with more minimally cushioned [[Saucony Endorphin]], and three with the near barefoot [[Merrell Vapor Glove]]. The first of each sequence was with my normal rear [[Foot Strike]], the second was with forefoot only landing without my heel ever making contact with the ground, and the third was forefoot landing with the heel briefly touching down. I compared the Sensoria with the [[RunScribe]] and the Garmin [[Running Dynamics]], and in the RunScribe graphs below, yellow is Ground Contact Time and blue is Foot Strike. As you can see from the table below, run scribe is reporting a Foot Strike number that is appropriate for how I was running. However, the Sensoria is reporting that time heel striking even when I'm running on my forefoot. The discrepancy between the Ground Contact Time results for the Sensoria, [[RunScribe]], and Garmin [[Running Dynamics]] laid me to do some verification tests later using high-speed video. This testing led me to believe that the Garmin was giving the most accurate results.
{| class="wikitable"
! Shoe
[[File:RS_Tracer_ForefootOnly.jpg|none|thumb|500px|The [[RunScribe]] data reflects the true Foot Strike pattern.]]
[[MilestonePod]] showed 100% forefoot, Ground Contact Time of 278ms, while [[Running Dynamics]] showed Ground Contact Time of 239ms. The [[Moov Now]] reported 7.7g impact, the [[RunScribe]] 10.0, and [[MilestonePod]] gave the rate of impact as low. However, the impact figures are measured in different ways and in different positions, so it's hard to meaningfully compare them.
=Ground Contact Time Testing=
I tested Ground Contact Time by comparing multiple devices against a gold standard of high-speed video on a treadmill. I took the average of a number of strides filmed over a 10 minute period, while aiming to run as steadily as possible. As you can see the Sensoria system is wildly inaccurate, and this reflects the general trend I've seen in my other runs. This test was with a [[Hoka Tracer]] shoe.
{| class="wikitable"
! Device
! Ground Contact Time (ms)
! Cadence
|-
| High Speed Video
| 256
|
|-
| Sensoria
| 344 (+88)
| 175 (fluctuating wildly)
|-
| Garmin [[Running Dynamics]]
| 254 (-2)
| 176
|-
| [[MilestonePod]]
| 253 (-3)
| 177
|-
| [[Moov Now]]
|
| 178
|}
Second test using the [[RunScribe]] system as well:
{| class="wikitable"
! Device
! Ground Contact Time (ms)
! Cadence
|-
| High Speed Video
| 255
|
|-
| Sensoria
| 339 (+84)
| 178
|-
| Garmin [[Running Dynamics]]
| 251 (+4)
| 177
|-
| [[MilestonePod]]
| 253 (-2)
| 177
|-
| [[RunScribe]]
| 299 (+44)
| 178
|}
Here's an example of the Sensoria cadence data, which reflects the wild fluctuations I saw displayed. <br/>
[[File:Sensoria Cadence.jpg|none|thumb|500px|Sensoria cadence data]]
=Replacement System=
When I contacted Sensoria, they initially told me that my system was working fine, but after further exchanges they suggested that I received a faulty sensor. Therefore I ordered a second sensor from Amazon and repeated some of my tests. Sadly, the results were pretty much identical. All three of these tests are with forefoot running, which I verified with high speed video analysis, as well as with [[RunScribe]]. As you can see, the patent of only randomly detecting the correct forefoot landing continues, as does the issue with incorrect Ground Contact Time.
{| class="wikitable"
|- valign="top"
|[[File:Sensoria2a.png|none|thumb|200px|]]
|- valign="top"
|[[File:Sensoria2b.png|none|thumb|200px|]]
|- valign="top"
|[[File:Sensoria2c.png|none|thumb|200px|]]
|}
