Table 2 Virtual coach actions related to state transitions and also permanence in the same state

1

\(State_{prev} = o\)  \(State = o\) \(Time>th_{pos}\)

Patient not well-positioned: VC suggests body repositioning; position rectangle in red color.

2

\(State_{prev} = \mathcal {S}/\{o,e,tg\}\)  \(State = o\)

Patient moves away from correct position: VC suggests body re-positioning; position rectangle in red color.

3

\(State_{prev} = o\)  \(State = i\)

Patient well-positioned: position rectangle in green color; VC gives exercise directions.

4

\(State_{prev} = i\)  \(State = e\)

Exercise beginning: VC displays target position marker (green).

5

\(State_{prev} = \mathcal {S}/\{o,i,tg\}\)  \(State = e\)

Patients stops moving: VC proposes movement repetition.

6

\(State_{prev} = e\)  \(State = n\)

The VC starts evaluating patient’s performance and asks one to reach the target position.

7

\(State_{prev} = \{tr,se,td,n\}\)  \(State = \{tr,se,td,n\}\) \(Time>th_{tg}\)

Patient takes too much time reaching the target position: VC encourages patient to reach the target.

8

\(State_{prev} = \{tr,se,td,n\}\)  \(state = tg\)

Patient reaches the target: VC praises the patient; target position marker in blue color.

9

\(State_{prev} = \{tr,se,td,n\}\)  \(State = tr\)

Patient describes trunk rotation: VC suggests posture correction; it displays trunk compensation marker (red).

10

\(State_{prev} = \{tr,se,td,n\}\)  \(State = se\)

Patient describes shoulder elevation: VC suggests correction; VC displays shoulder compensation marker (red).

11

\(State_{prev} = \{tr,se,td,n\}\)  \(State = td\)

Patient describes displaces the torso: VC suggests posture correction; VC displays trunk compensation marker (red).