Anaerobic Power: Measurement Methods, Importance, and Interpretation

How is anaerobic power measured?

Anaerobic power, a crucial component of athletic performance, is primarily measured through specialized laboratory and field tests that assess an individual's ability to produce maximal work over short durations, relying on immediate energy systems.

What is Anaerobic Power?

Anaerobic power refers to the maximal rate at which an individual can produce energy through the anaerobic (without oxygen) metabolic pathways. These pathways include the adenosine triphosphate-phosphocreatine (ATP-PCr) system, which provides immediate energy for very short, high-intensity efforts (up to ~10 seconds), and anaerobic glycolysis, which fuels slightly longer, high-intensity activities (up to ~2 minutes). Unlike aerobic power, which focuses on sustained energy production, anaerobic power is about explosive, short-burst capabilities vital for sports requiring sprinting, jumping, throwing, or rapid changes of direction.

Why Measure Anaerobic Power?

Measuring anaerobic power provides invaluable insights for various populations:

• Athletic Performance Assessment: It helps identify strengths and weaknesses in athletes, guiding specific training interventions for sports like track and field (sprinting, jumping), team sports (soccer, basketball), combat sports, and weightlifting.
• Talent Identification: High anaerobic power can be an indicator of potential in certain sports.
• Training Program Evaluation: Tracking changes in anaerobic power over time allows coaches and athletes to assess the effectiveness of training programs.
• Rehabilitation and Return to Sport: For injured individuals, assessing anaerobic power can help determine readiness to resume high-intensity activities.
• Research and Scientific Study: Understanding human physiological responses to exercise and the efficacy of different training modalities.

Direct Measurement Methods

Direct measurements typically involve laboratory settings using specialized equipment to quantify power output precisely.

Wingate Anaerobic Test (WAnT)

The Wingate Anaerobic Test (WAnT) is considered the gold standard for assessing anaerobic power and capacity.

• Procedure: Performed on a cycle ergometer (e.g., Monark or Lode) with a specific resistance applied based on body mass (typically 0.075-0.10 kg per kg body weight). The individual pedals maximally for 30 seconds against this resistance. The ergometer measures revolutions per minute (RPM) and resistance, allowing for real-time power calculations.
• Key Metrics Measured:
  • Peak Power Output (PPO): The highest power output achieved during any 5-second interval of the test, reflecting the capacity of the ATP-PCr system. Usually expressed in Watts (W) or Watts per kilogram (W/kg).
  • Mean Power Output (MPO): The average power output over the entire 30-second test, reflecting the overall capacity of both the ATP-PCr and anaerobic glycolytic systems. Also expressed in W or W/kg.
  • Fatigue Index (FI): The percentage decrease in power from the peak power to the lowest power output, indicating an individual's ability to maintain high intensity and resistance to fatigue. Calculated as ((Peak Power - Minimum Power) / Peak Power) * 100.
• Advantages: Highly reliable and valid, provides comprehensive data on both peak and sustained anaerobic performance.
• Disadvantages: Requires specialized and expensive equipment, significant participant motivation, and trained personnel for administration.

Vertical Jump Test

The Vertical Jump Test is a widely used and practical method to assess lower body explosive power, which is largely anaerobic.

• Procedure: Individuals typically start from a standing position, squat down, and jump as high as possible, reaching to touch a marker or using a force plate.
• Measurement:
  • Jump Height: Measured directly using a wall-mounted ruler, Vertec device, or indirectly via motion capture or force plates.
  • Power Calculation: While jump height is the primary outcome, force plates can provide more precise data (force and velocity) to calculate peak power and mean power during the jump. Simpler equations, such as the Lewis Equation (Power (W) = √(4.9 x body mass (kg) x √jump height (m)) x 9.81), or the Sargent Jump Test method can estimate power from jump height and body mass.
• Advantages: Simple, relatively inexpensive, good correlation with sport-specific performance.
• Disadvantages: Less precise than the WAnT, relies on various calculation models, and technique can influence results.

Stair Climb Test (e.g., Margaria-Kalamen Test)

The Margaria-Kalamen Test is a classic method to assess peak anaerobic power using a stair climb.

• Procedure: The individual starts 6 meters from a flight of stairs and sprints up the stairs, skipping steps (e.g., taking every third step). Timing typically begins as the foot lands on the third step and ends when the foot lands on the ninth step.
• Measurement: Power is calculated using the formula: Power (W) = (Body Mass (kg) x Vertical Distance (m)) / Time (s). The vertical distance is the height between the third and ninth steps.
• Advantages: Simple, requires minimal equipment, good for assessing explosive leg power.
• Disadvantages: Difficult to standardize technique, risk of falling, limited to peak power, not mean power.

Field-Based and Indirect Measurement Methods

These methods are often more practical for large groups or in settings without specialized lab equipment, though they may be less precise.

Sprint Tests

Short-distance sprint tests are excellent indicators of anaerobic power, especially the ATP-PCr system.

• Procedure: Maximal effort sprints over distances like 10, 20, 30, 40, or 60 meters.
• Measurement: Time to complete the distance is recorded using timing gates or stopwatches. While not directly measuring power in Watts, faster times over these distances directly correlate with higher anaerobic power output.
• Advantages: Highly sport-specific for many activities, easy to administer, no specialized equipment beyond timing.
• Disadvantages: Does not provide direct power values, highly dependent on acceleration phase, and technique can influence results.

Repeated Sprint Ability (RSA) Tests

RSA tests assess an individual's ability to repeatedly produce maximal or near-maximal efforts with short recovery periods, reflecting both anaerobic power and fatigue resistance.

• Procedure: Typically involves multiple short sprints (e.g., 6 x 20m, 10 x 30m) with brief recovery intervals (e.g., 20-30 seconds).
• Measurement: Total time for all sprints, average sprint time, and fatigue index (increase in sprint time over repetitions).
• Advantages: Mimics demands of many team sports, provides insight into fatigue resistance.
• Disadvantages: Not a direct measure of peak power, can be influenced by aerobic capacity and pacing.

Power Output on Ergometers (Indirect)

While the WAnT is a direct measure, other ergometer protocols can provide indirect assessments of anaerobic power.

• Procedure: Performing short, maximal efforts on cycle ergometers, rowing ergometers, or even resistance training machines equipped with power meters.
• Measurement: The ergometer's software calculates power output based on resistance and speed of movement. For example, a cycle ergometer can measure peak power during a 10-second maximal sprint.
• Advantages: Objective data, widely available in gyms and training facilities.
• Disadvantages: May not fully replicate specific sport movements, some ergometers are better for sustained power than explosive peak power.

Interpreting Anaerobic Power Results

Interpreting results requires understanding the context:

• Normative Data: Comparing an individual's results to published normative data for their age, sex, and sport can provide a benchmark.
• Sport-Specific Demands: A sprinter will prioritize high peak power, while a basketball player might need strong mean power and fatigue resistance.
• Longitudinal Tracking: The most valuable interpretation comes from tracking an individual's own results over time to assess training effectiveness and identify performance trends.
• Relative vs. Absolute Power: Power is often expressed relative to body mass (W/kg) to allow for comparisons between individuals of different sizes, especially in weight-bearing activities. Absolute power (W) is important for activities where body mass is less of a factor (e.g., cycling).

Considerations for Accurate Measurement

Several factors can influence the accuracy and reliability of anaerobic power measurements:

• Standardized Protocols: Strict adherence to test protocols (warm-up, resistance settings, recovery times, verbal encouragement) is crucial.
• Equipment Calibration: Ensuring all equipment (ergometers, timing gates, force plates) is regularly calibrated.
• Participant Motivation: Maximal effort is required for valid results; consistent motivation and encouragement are key.
• Fatigue Status: Participants should be well-rested and not fatigued from previous training.
• Environmental Conditions: Temperature, humidity, and altitude can affect performance.
• Technical Proficiency: For tests like the vertical jump or stair climb, proper technique is essential to maximize output and ensure valid results.

Conclusion

Measuring anaerobic power is a fundamental practice in exercise science, sports performance, and rehabilitation. While the Wingate Anaerobic Test remains the laboratory gold standard for its comprehensive assessment of peak power, mean power, and fatigue index, a variety of direct and field-based methods offer practical, valid, and reliable alternatives. By understanding the physiological basis of anaerobic power and employing appropriate testing protocols, coaches, trainers, and athletes can gain critical insights to optimize training, enhance performance, and mitigate injury risk.