This could be caused by a few things:

  • You made some error during setup, or
  • There's strong electromagnetic interference with the sensors

To be sure, the first thing to do is to start over:

  1. Turn off all the sensors
  2. Close the app
  3. Put all sensors back into the sensor  box
  4. Reboot the app
  5. Choose your pro and stroke
  6. Choose Learn or Virtual Practice
  7. Let the app walk you through setup again.

When you go back through setup, here are some things to watch out for:

  • When asked to lay the sensors flat, be sure they remain still.
  • Make sure sensors are inserted straight into pockets. They should not be twisted or angled.
  • Make sure your chest harness, glove, and armband are fitting snugly and are positioned correctly on your body
  • Make sure the racquet sensor is completely snapped onto your strings. It should not jiggle or move at all as you swing.
  • During body calibration, make sure your racquet is pointing in the exact same direction as your body