Although running may seem to be one of those things that we "just do," there are right and wrong ways of going about it seriously. Invented by French physiotherapist Vieilledent Frédéric, the iKinesis system is intended to help runners get it right.
The hardware end of the setup consists of a "Kapsule" unit that is fastened to the laces of one of the user's shoes. Among other things, that device contains an IMU (inertial measurement unit), a microprocessor, a Bluetooth module and a rechargeable battery. It wirelessly communicates with an app on the user's smartphone in real time, although it also stores data for subsequent download, if the phone isn't accessible during the run.
In either case, when the user checks the app, they will receive feedback and advice on factors such as the pronation of their foot (and presumably by extension both feet), the foot's impact force against the ground, vertical oscillations in their center of gravity, the length of their strides, the foot's contact time on the ground, propulsion efficiency and cadence.
Additionally, the system can be set to warn users of problems while they're running, via vibrational or auditory alerts on the phone.
The Kapsule itself reportedly tips the scales at 10.8 grams, is IP68 waterproof (it can be submerged to 1.5 m/4.9 ft for 30 minutes), and should run for six hours per one-hour charge of its battery.
iKinesis is currently the subject of a Kickstarter campaign, where a pledge of €139 (about US$166) is required for a setup. Assuming it reaches production, it should ship in October. You can see it in use, in the video below.
Sources: Kickstarter, iKinesis