Arrange the following procedural steps to conduct the Harvard Step Test in a sequential order from first to last:

(A) Start at command ”Go”
(B) Stepping up and down in a four-count sequence on the bench
(C) Measure heart rate from one to one and a half minutes
(D) Compute fitness index score
(E) Sit down after completion of the exercise

The correct option is (A), (B), (E), (C), (D).

To understand why this is the correct sequence, let's break down the procedure of conducting the Harvard Step Test step-by-step:

1. (A) Start at command ”Go”: The test begins with the administrator giving the signal to start. This is the initial step to ensure proper timing.

2. (B) Stepping up and down in a four-count sequence on the bench: Once the test starts, the subject performs the physical exercise, stepping up and down on the bench at a constant rate (usually 30 steps per minute) following a four-count rhythm (up-up-down-down) for up to 5 minutes.

3. (E) Sit down after completion of the exercise: Immediately after the stepping exercise is completed or the subject is exhausted, they must sit down and rest quietly to transition to the recovery and measurement phase.

4. (C) Measure heart rate from one to one and a half minutes: During recovery, the heart rate (pulse) is measured at specific intervals. The first recovery pulse count is taken from 1 to 1.5 minutes after finishing the exercise.

5. (D) Compute fitness index score: Finally, using the duration of the exercise and the recorded heart rate recovery pulses, the physical fitness index (PFI) score is calculated using the standard formula. This concludes the test procedure.

Therefore, chronological ordering of the steps is (A) → (B) → (E) → (C) → (D).