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Cross-validation of three jump power equations
S P Sayers1, D V Harackiewicz, E A Harman
1Department of Physical Education, Health Fitness Studies, Central Connecticut State University, New Britain 06050, USA. ssayers@excsci.umass.edu
Medicine and Science in Sports and Exercise
|April 22, 1999
Summary
A new equation derived from squat jump (SJ) data provides a more accurate estimation of peak power than previous methods. This validated equation simplifies power calculations for both genders, improving athletic performance analysis.
Area of Science:
- Sports Science
- Biomechanics
- Human Performance
Background:
- Existing equations by Lewis and Harman et al. utilize vertical jump-and-reach scores to estimate peak mechanical power.
- The accuracy and applicability of these equations across diverse populations and jump types require further validation.
Purpose of the Study:
- To cross-validate existing peak power estimation equations using the vertical jump-and-reach test.
- To develop a more accurate prediction equation for peak power from a large, heterogeneous population.
- To investigate gender differences, analyze jump protocols (squat jump vs. countermovement jump), and assess cross-validation methods (PRESS).
Main Methods:
- One hundred eight college-aged athletes and non-athletes performed squat jumps (SJ) and countermovement jumps (CMJ) on a force platform.
- Vertical jump height and body mass were measured simultaneously with the vertical jump-and-reach test.
- Regression analysis was employed to derive and validate peak power prediction equations.
Main Results:
- The squat jump (SJ) protocol yielded a more accurate peak power prediction equation compared to the countermovement jump (CMJ) due to less technique variability.
- A novel SJ-derived equation (Peak Power [W] = 60.7 × [jump height cm] + 45.3 × [body mass kg] - 2055) demonstrated superior accuracy and underestimated peak power by less than 1% (SEE = 355.0 W).
- This new equation showed minimal gender differences (5% of power output) and slight overestimation (2.7%) when applied to CMJ data. Predicted Residual Sum of Squares (PRESS) confirmed equation reliability.
Conclusions:
- The derived squat jump (SJ) equation offers improved accuracy for peak power estimation compared to equations using countermovement jump (CMJ) data.
- This SJ equation is recommended for determining peak power, superseding previous formulas by Harman et al. and Lewis.
- A single, gender-neutral equation is sufficient for accurate peak power calculations.