Time

Case

Level 0

(−)

Level 1

(+)

Level 2

(++)

Level 3

(+++)

The strain phase

57

30 (52.63%)

16 (28.07%)

7 (12.28%)

4 (7.02%)

The release phase

57

9 (15.79%)

5 (8.77%)

11 (19.30%)

32 (56.14%)