VX Sport now offers 5 graded zones for body impacts, available in the training report and VX Live.
The purpose of an "impact" or “collision” metric should be to report on the transfer of energy or change in momentum that occurs when a human body travelling at speed changes velocity. These "impacts" are measured using a motion sensored chip inside the GPS unit which records 3 axis accelerometer, magnetometer and gyroscope data.
Unlike other companies that report upon the peak acceleration that occurs, reported as units of gravity, without taking into consideration the time in which the acceleration was applied. We here at VX Sport have created a system that does not place specific values to the energy transfer, but instead creates a sensing system that can be calibrated to real world “body impacts.” Effectively the new metric has a threshold that assesses each impact event, decides which are significant and counts these.