The speed of the trainer is simply the speed recorded with the ANT+ sensor from your rear wheel.
The speed shown by default is the "virtual speed", calculated in real time to have an estimate of what would be your real speed in the outside world. It is possible to change the default speed in the workout options if you wish.
This speed is calculated with your Power, your weight, and other parameters set in your profile.
It is possible to create a private Category for the athletes you coach, so that only the group members you select can access the category.
If you are a coach and would like a special Category, just send me a message with the Group name you would like.
When new users want to join the group, they need to select the "Groups" icon, click the desired group and then choose "request access". The group moderator can then accept/refuse the new member.