Exercise & Motion Analysis 1

Collecting motion data

There are a number of apps (e.g. MotionX) that allow users to monitor their latitude, longitude and elevelation over time. You can analyze your power, kinetic energy, gravitational potential energy, and other parameters during exercise by analyzing details of of the files that are generated by the apps. The primary file types are:

  • TCX files are created by fitness devices and can have heart rate, cadence and power data along with the standard gps data of time, elevation and coordinates. These files can give the most complete data for fitness analysis.
  • GPX files are created by all other non-fitness gps units and have only time, elevation and coordinates.
  • KML & KMZ files are used to display your track in Google Earth.

Analysis of the physics of your exercise

Sample files: These are short mountain bike rides that I have taken in the local mountains. Each trip is a "round trip" in which I started and ended at the same place. View the course of each using MotionX website and Google Earth.

Analyze trips - Analyze the gpx files of these trips using Utrack.

Rider Information. For the GPX files included in this report, please use the following values. For your own routes, please include your information when performing calculations.

  • Mass of rider: 100 kg
  • Mass of bicycle: 20 kg
  • Mass of each wheel: 2 kg
  • radius of wheel: 0.315 m


  • Maximum speed v=d/t (m/s)
  • Maximum gravitational potential energy of rider & bike (joules) E(p)=mgh (J)
  • Maximum slope (percent) slope = (rise/run)x100% (%)
  • Maximum kinetic energy of rider and bike (joules) E(k)=1/2mv^2 (J)
  • Maximum rotational inertia of bicycle I=mr^2 (kgm^2)
  • Average power output from starting point to summit (watts) P(ave)=W/t (W)
  • Maximum power output (watts) P=W/t (W)
  • Enter your data in the form below and then compare your calculations with those of others

When you are done with this activity, try Exercise & Motion Analysis 2