Q.The Physical Fitness Index in the Harvard Step Test is computed as:

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This is an MCQ with four printed options. The task is to identify the correct formula for the Physical Fitness Index (PFI) in the Harvard Step Test, explain why it is correct, and refute the other three.

Solution

The Harvard Step Test measures cardiovascular fitness by having a subject step up and down on a bench at a fixed rate for up to five minutes. After exercise, the pulse is counted for 30 seconds in the interval from 1 to 1.5 minutes post-exercise. The Physical Fitness Index is then calculated.

The prescribed formula is:

PFI = (Duration of exercise in seconds × 100)/(5.5 × Pulse count (1 to 1.5 min after exercise))

This formula rewards longer exercise duration (better endurance) and penalizes a higher pulse count (poorer recovery). The constant 5.5 scales the denominator appropriately, and multiplying the numerator by 100 yields an index value that falls into the interpretation bands: up to 49 = Poor, 50–80 = Average, 81 and above = Good.

Option (a) matches this formula exactly.

Option (b) inverts the relationship: it places pulse count in the numerator and duration in the denominator. This would mean a higher pulse (worse recovery) increases the PFI, which contradicts the test's purpose. …

Harvard Step Test Formula

The Harvard Step Test measures cardiovascular endurance by tracking how quickly the heart recovers after a standardized stepping exercise. A subject steps up and down on a bench at 30 steps per minute for up to 5 minutes, then sits immediately. Between 1 and 1.5 minutes after stopping, the pulse is counted for exactly 30 seconds. The Physical Fitness Index formula converts these two measurements — exercise duration and recovery pulse — into a single score that reflects aerobic fitness.

The logic is straightforward: longer exercise duration means better endurance, and a lower recovery pulse means faster cardiovascular recovery. The formula rewards both by placing duration in the numerator and pulse in the denominator. The constants 100 and 5.5 scale the result into the standard interpretation bands.

Duration is the total time the subject actually stepped, in seconds. If the full 5 minutes are completed, this is 300 seconds. If the subject stops early due to fatigue, you use the actual seconds stepped — never assume 300.

Pulse count is the raw 30-second count taken in the recovery window from 1:00 to 1:30 after exercise stops. This is not converted to a per-minute rate; you use the count exactly as recorded.

The factor 5.5 and the multiplication by 100 are constants that calibrate the index to the prescribed interpretation bands: up to 49 is Poor, 50 to 80 is Average, and 81 and above is Good.

Why each option is right or wrong

(a) states the formula exactly as prescribed: duration in seconds times 100, divided by 5.5 times the pulse count. This matches the structure and constants of the official formula.

(b) inverts the relationship, placing pulse in the numerator and duration in the denominator. That would reward a higher pulse and penalize longer exercise — the opposite of what cardiovascular fitness means. A fitter person has a lower recovery pulse and sustains exercise longer, so both should improve the score, not worsen it. …