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From Fellrnr.com, Running tips
SHFT
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* '''Vertical Osculation'''. It seems intuitively obvious that excessive vertical movement is a sign of an inefficient runner, but I've not found any research indicating if there is an optimal value for Vertical Oscillation. A runners' vertical movement is partly based around the elastic properties of the leg muscles and tendons, so not all vertical motion is bad. SHFTs measurement of Vertical Oscillation, which they call "body balance" is far too low. I measured my Vertical Oscillation using Ice Speed Video Analysis to be 3.5"/8.75cm, but SHFT said it was 2.2"/5.5cm. Worse, the real time display on the smartphone app showed less than 1"/2.5cm.
* '''Impact'''. SHFT calls [[Impact]] "G-Landing" and says it's "the maximum force of impact upward through the body from when the foot hits the ground to flatfoot" and they talk about this impact being "normalized." I find this all confusing on several levels, not least of which is the value displayed for my running seems a rather low at generally less than 2.0g. I'm not sure if this is the impact forces measured on the chest strap on the Footpod, or combination of the two.
* '''Landing angle'''. Unlike other systems, SHFT provides an angle of landing rather than a simple classification or in the case of [[RunScribe]] an arbitrary numeric indicator. My simplistic testing suggests that this is reasonably accurate, but I will attempt to verify it using The results look pretty good based on [[High-Speed Video Analysis]].{| class="wikitable" style="margin-left: auto; margin-right: auto; border: none;"|- valign="top"|[[File:SHFT-LandingRFS.jpg|right|thumb|x150px|Estimating the landing angle from High Speed Video Analysis.]]|[[File:SHFT-LandingFFS.jpg|right|thumb|x150px|The measured angle while Forefoot landing.]]|}* '''Foot Strike'''. Based on the landing angle, SHFT gives a classification of the foot landing position into things like "neutral midfoot." The SHFT website will go even further and give a diagram of your foot showing what percentage of the time you land on what part of the foot.This looks reasonable when I tested with different foot strike patterns. (I confirmed my foot strike with [[High-Speed Video Analysis]].){| class="wikitable" style="margin-left: auto; margin-right: auto; border: none;"|- valign="top"|[[File:SHFT Landing PositionRFS.jpg|right|thumb|x150px|This is the pattern for my regular rearfoot strike. SHFT does a better job than some systems of evaluating where the greatest force is applied rather than the point of initial contact.]]|[[File:SHFT Landing PositionFFS.jpg|right|thumb|x150px|]]|}* '''Toe off angle'''. SHFT is unique (so far) in displaying the foot angle at toe off. It's unclear how useful this is, but I have noticed my toe off angle decreasing as I become fatigued.I evaluated this using [[High-Speed Video Analysis]], but it's tricky to confirm. The images below are from a single stride, where SHFT reported 37 degrees at toe off. {| class="wikitable" style="margin-left: auto; margin-right: auto; border: none;"|- valign="top"|[[File:SHFT_ToeOff1.jpg|right|thumb|x200px|This is the point in the stride where I'd say I had maximum toe off, and the angle is about right. ]]|[[File:SHFT_ToeOff3.jpg|right|thumb|x200px|I'd say that by this point in the stride my toes have left the ground and just the shoe is in contact, but you see the ambiguity.]]|[[File:SHFT_ToeOff2.jpg|right|thumb|x200px|There's also more than one way of measuring the angle. I'd measure toe off as the metatarsal angle, but you could use this approach.]]|}
Given the nature of the SHFT system, there are a few things that seem noteworthy by their absence. Most glaring omission is the lack of pace information, some think you get from virtually all Footpod sensors. I also think they could to rather more with impact measurement given that they're detecting it on two different body parts. I'm also concerned with the difficulty in using the SHFT system with a chest strap heart rate monitor.
=Real Time Feedback=
|- valign="top"
|[[File:SHFT App Angle.png|none|thumb|250px| He is the display of landing angle for a run where I swapped to forefoot running towards the end. You can see the SHFT system detected this a change in foot strike quite nicely. You can also see the raw data displayed in gray, with the smooth data shown in green. I rather like having the display show both raw and smooth data.]]
|[[File:SHFT App Bounce.PNG png | None | Thumb | 250px|]] The visual explanation of Vertical Oscillation is rather nice.
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|[[File:SHFT Overview.jpg|none|thumb|250px| The website also shows a summary of all the metrics for a run, along with a map. Because there's no treadmill mode, this is a little less than useful when running indoors.]]
