There are several ways to estimate power from the vertical jump test. The standard formula for power is:
Power = (Force x Distance) / Time
Where:
- Force is the weight of the person (in kg)
- Distance is the height of the jump (in meters)
- Time is the duration of the jump (in seconds)
Some basic formulas to calculate power (expressed in Watts) is:
- Power = (2.21 x Jump Height) + (0.23 x Weight) - 0.013 x Age + 5.4
- Power = (Jump Height x 9.81 x Weight) / 4.45
- Power = (Jump Height x 9.81 x Weight) / 4.45 + 30.48
However, we are dealing with the human body, so reality is more complex. Muscles don't generate force at a constant rate, and the body doesn't move at a constant speed. Sport scientists have developed ways to estimate the average power and a peak power.
We will calculate using several of the common formulas.
vertical_jump.lewisPower = sqrt(4.9) * vertical_jump.weight * sqrt(vertical_jump.jump_height / 100) * 9.81;
vertical_jump.harmanPeakPower = (61.9 * vertical_jump.jump_height) + (36.0 * vertical_jump.weight) + 1822;
vertical_jump.harmanAveragePower = (21.2 * vertical_jump.jump_height) + (23.0 * vertical_jump.weight) - 1393;
vertical_jump.johnsonPeakPower = (78.6 * vertical_jump.jump_height) + (60.3 * vertical_jump.weight) - (15.3 * participant.age) + 1308;
vertical_jump.johnsonAveragePower = (43.8 * vertical_jump.jump_height) + (32.7 * vertical_jump.weight) - (12.7 * participant.age) + 1308;
vertical_jump.sayersPeakPower = (60.7 * vertical_jump.jump_height) + (45.3 * vertical_jump.weight) - 2055;
Which formula do you want to use for your primary power calculations?
Lewis Formula
One of the first and most basic formulas for calculating average power.
- Average Power (W): Average Power = √(4.9) x Weight (kg) x √(Jump Height (m)) x 9.81
- Result:
vertical_jump.lewisPower
Harman Formula
This formula was developed by Harman et al. (1991) and provides equations for both peak and average power.
- Peak Power (W): Peak Power = 61.9 x jump height (cm) + 36.0 x weight (kg) + 1,822
- Result:
vertical_jump.harmanPeakPower - Average Power (W): Average Power = 21.2 x jump height (cm) + 23.0 x weight (kg) - 1,393
- Result:
vertical_jump.harmanAveragePower
Johnson & Bahamonde Formula
Developed by Johnson and Bahamonde (1996), this formula also calculates both peak and average power using the countermovement jump.
- Peak Power (W): Peak Power = 78.6 x jump height (cm) + 60.3 x weight (kg) - 15.3 x age (years) + 1,308
- Result:
vertical_jump.johnsonPeakPower - Average Power (W): Average Power = 43.8 x jump height (cm) + 32.7 x body mass (kg) - 12.7 x age (years) + 1,308
- Result:
vertical_jump.johnsonAveragePower
Sayers Formula
The Sayers Equation (Sayers et al. 1999) estimates peak power output.
- Peak Power (W): Peak Power = 60.7 x jump height (cm) + 45.3 x weight (kg) - 2,055
- Result:
vertical_jump.sayersPeakPower
Choose the formula that best fits your needs or consult with a fitness professional for guidance.
Where is Time in the formulas?
You may have noticed that the basic power formula includes time.
You are probably wondering why the formulas we use don't include time.
The time of the jump is not typically measured in the vertical jump test.
This is because measuring the time accurately requires special equipment.
The formulas estimate the time of the jump based on the jump height and the acceleration due to gravity (9.81 m/s^2).