During each phase, the therapist can complicate or
simplify motor, environment, and cognitive aspects of
the tasks in accordance with the abilities of each participant.
Each aspect can be changed in a stable or a variable
way [10]. For example, the weight or height of an
exercise, the number of repetitions, and the difficulty of
the exercise can be changed. Alternatively, participants
can be asked to count backwards, select objects in a specific
order or work together