Astrand Treadmill Test

The Astrand Treadmill Test: Submaximal Assessment of Aerobic Capacity

Abstract

The Astrand treadmill test is a physiological assessment tool designed to estimate maximal oxygen consumption (VO2 max) based on the heart rate response to a "submaximal" workload. This protocol allows for the evaluation of cardiorespiratory fitness in both athletes and general populations without the necessity of reaching the point of complete exhaustion, making it both safe and practical for various training environments.

1. Required Equipment

  • Treadmill with adjustable speed and incline settings.
  • Accurate heart rate monitor (chest strap or ECG sensor).
  • Stopwatch.
  • Scale for measuring body mass.
  • Calculator for applying estimation formulas.

2. Testing Protocol

  • Warm-up: 5 minutes of light walking or jogging (4–5 km/h) at 0% incline.
  • Submaximal Effort Phase: Set the treadmill speed between 5 and 6 km/h, depending on the subject's fitness level. Set the incline to 5% for beginners, and up to 8–10% for trained athletes. Maintain these settings consistently for 6 minutes.
  • Data Recording: Record the average heart rate during the final 30 seconds of the effort (FC6).

3. Mathematical Equations and Evaluation

The accuracy of the results depends on applying the following two equations in order:

Step 1: Calculate the Oxygen Consumption for the Stage (VO2p): Using the ACSM walking/running equation: VO2p = (0.1 × v) + (1.8 × v × G) + 3.5

  • v: Velocity in meters per minute (m/min).
  • G: Decimal grade (e.g., 5% incline = 0.05). (Note: To convert km/h to m/min, multiply speed by 16.67).

Step 2: Calculate the Predicted VO2 max: VO2 max = VO2p × (FC max / FC6)

  • FC max: Theoretical maximum heart rate (220 – age).
  • FC6: Average heart rate recorded during the 6th minute.

4. Classification Standards (ml·kg⁻¹·min⁻¹)

Results are classified according to the following levels:

  • Below 30: Low aerobic capacity.
  • 30 – 40: Average level.
  • 40 – 50: Good level.
  • 50 – 60: Very good level.
  • Above 60: Excellent level (Elite athlete).

5. Technical Recommendations

  • Consistency: Always conduct the test under the same environmental conditions (time of day, temperature, hydration level).
  • Recovery: It is recommended to avoid intense training for 48 hours prior to the test to ensure no residual fatigue affects the heart rate response.
  • Longitudinal Tracking: Utilize the test periodically to monitor physiological adaptations and adjust training plans based on changes in aerobic capacity.

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