Someone may be required to manage the treadmill or ensure all work is done ont he water walker. To add a person to manage the exercise, they must be set up as a Practitioner before they can be added to the exercise.
To add as a Practitioner go to People, select or add a person's record and select the role Practitioner.
Once this is done, go tot he Exercise grid, select the pencil next to the work section the person will be running and select their name from the drop down list. All work in the column will be assigned to the person.