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Vertical Jump Power Calculation
Vertical Jump tests are usually just reported as the distance jumped in centimeters or inches. This does not always tell the full story. A heavier person jumping the same height as a lighter one has to do much more work to move a larger mass. Therefore it is sometimes useful to convert the score to units of power or work.
The mechanical work performed to accomplish a vertical jump can be determined by using the jump height distance that was measured (using Work = Force x Distance where Force = Mass x Acceleration). However, Power can not be calculated (Power = Work / time) since the time that force is acted on the body is unknown. Power can be directly measured using a force plate, though these are not readily available. Over time a few different formula have been developed that estimate power from vertical jump measurements. A few of these are presented below, with examples.
The examples below all use a hypothetical vertical jump of 60 cm (0.6 meters or 23.5 inches) by a person 75 kg and 180 cm. As you can see, there are widely different results achieved. This is partly due to it not always being clear if peak power or average power is being estimated.
Lewis Formula
The Lewis formula or nomogram (Fox & Mathews, 1974) is a commonly used formula (found in many high school text books). This formula only estimates average power, and is based on a modified falling body equation. The original formula used the units of kg·m·sec.-1. To convert it to Watts, the standard unit for Power, factor of 9.81 has been added.
Average Power (Watts) = √4.9 · body mass (kg) · √jump-reach score (m) · 9.81
Example
- Average Power = (square root of 4.9) x body mass(kg) x (square root of jump distance(m)) x 9.81
- Average Power = 2.2136 x 75 x 0.7746 x 9.81
- Average Power = 1261.6 Watts
Harman Formula
To improve on the limitations of the Lewis formula, Harman et al. (1991) established equations for both peak and average power through multiple regression procedures. The two equations are listed below:
Peak power (W) = 61.9 · jump height (cm) + 36.0 · body mass (kg) + 1,822
Average power (W) = 21.2 · jump height (cm) + 23.0 · body mass (kg) – 1,393
Examples
- Peak power (W) = (61.9 x jump height (cm)) + (36 x body mass (kg)) + 1822
- Peak power (W) = (61.9 x 60) + (36 x 75) + 1822
- Peak power (W) = 3714 + 2700 + 1822
- Peak power (W) = 8236 Watts
- Average power (W) = (21.2 x jump height (cm)) + (23.0 x body mass (kg)) – 1393
- Average power (W) = (21.2 x 60) + (23 x 75) - 1393
- Average power (W) = 1272 + 1725 - 1393
- Average power (W) = 4390 Watts
Johnson & Bahamonde Formula
Johnson and Bahamonde (1996) also developed formula for the calculation of peak and average power from the vertical jump test, using the countermovement jump. These equation use the additional factor of body height.
Power-peak (W) = 78.6 · VJ (cm) + 60.3 · mass (kg) -15.3 · height (cm) -1,308
Power-avg (W) = 43.8 · VJ (cm) + 32.7 · mass (kg) -16.8 · height (cm) + 431
Examples
- Peak power (W) = (78.6 x VJ (cm)) + (60.3 x mass (kg)) - (15.3 x height (cm)) -1308
- Peak power (W) = (78.6 x 60) + (60.3 x 75) - (15.3 x 180) - 1308
- Peak power (W) = 4716 + 4522.5 - 2754 - 1308
- Peak power (W) = 5176.5 Watts
- Average power (W) = (43.8 x VJ (cm)) + (32.7 x mass (kg)) - (16.8 x height (cm)) + 431
- Average power (W) = (43.8 x 60) + (32.7 x 75) - (16.8 x 180) + 431
- Average power (W) = 2628 + 2452.5 - 3024 + 431
- Average power (W) = 2487.5
Sayers Formula
The Sayers Equation (Sayers et al. 1999) also estimates peak power output (Peak Anaerobic Power output or PAPw) from the vertical jump.
PAPw (Watts) = 60.7 · jump height(cm) + 45.3 · body mass(kg) - 2055
Example
- PAPw = (60.7 x jump height(cm)) + (45.3 x body mass(kg)) - 2055
- PAPw = (60.7 x 60) + (45.3 x 75) - 2055
- PAPw = 3642 + 3397.5 - 2055
- PAPw = 4984.5 Watts
References
- Bosco C, Luhtanen P, Komi PV (1983) A simple method for measurement of mechanical power in jumping. European Journal of Applied Physiology 50:273-282.
- Harman, E.A., Rosenstein, M.T., Frykman, P.N., Rosenstein, R.M., and Kraemer, W.J.
(1991). Estimation of Human Power Output From Vertical Jump. Journal of Applied Sport Science Research, 5(3), 116-120. - Johnson, D.L., and Bahamonde, R. (1996). Power Output Estimate in University Athletes. Journal of strength and Conditioning Research, 10(3), 161-166.
- Keir, P.J., V.K. Jamnik, and N. Gledhill. (2003) Technical-methodological report: A nomogram for peak leg power output in the vertical jump, The Journal of Strength and Conditioning Research Volume: 17 Issue: 4 Pages: 701-703.
- Sayers, S., et al. (1999) Cross-validation of three jump power equations. Med Sci Sports Exerc. 31: 572.
Related Pages
- procedure for Vertical Jump Testing and using the Timing Mat method
- Vertical Jump test results
- converting vertical jump units between cm and inches
- vertical jump devices in the fitness testing store
