A Novel Equation to Predict Peak Power in Young Athletes James Tufano,1 William E. Amonette,1 Denham Brown,1 Lee E. Brown,2 Terry L. Dupler,1 Tai T. Tran,2 Junhai Xu,1 Barry A. Spiering2  1University of Houston-Clear Lake, Human Performance Laboratory, Houston, TX, 2California State University, Fullerton Abstract Expression of power in triple extension movements is a key to success in many sports. Although power can be measured directly with a force plate, several field equations using vertical jump height (VJ) and body mass (BM) have been developed to predict peak power. Generally, these previously published equations were derived from relatively small numbers (N = 17 to 108) of adults  with an average age of 22.0 years. Estimating power using these equations may not be ideal for young athletes. PURPOSE: The purpose of this study was to develop a novel equation to estimate peak power in young athletes and to compare its accuracy against previously published equations. METHODS: VJ data were collected from two hundred and seventy (N=270) youth soccer players. The first two hundred and fifty five (n=255; 14.1 ± 1.8 y) were used to model a new equation to predict peak power. A validation sample was collected at a later time on fifteen different soccer players (n=15; 15.9 ± 1.1 y). All athletes completed a general warm-up, eight dynamic stretches, and a series of jumps to prepare for maximal testing. After a thorough explanation of procedures, BM was determined on each athlete and they were permitted to perform two practice jumps on the force plate. Data were collected at 400 Hz while the subjects performed a single maximal counter movement VJ on the force plate with a wooden dowel held securely across their shoulders. Peak power (PP) and VJ height were derived from a commercial software program. A multivariate regression equation was developed using VJ and BM to predict PP using the original 255 athletes. Using the validation sample (n= 15), the actual PP was compared to power estimated using the novel equation and three previously established equations (Sayers et al 1999; Harman et al. 1991; and Canavan  et al. 2004) using Repeated Measures Analysis of Variance (ANOVA). Holms-Sidak post hoc test was used for pairwise comparisons with an alpha of p <0.05. RESULTS: To account for a slight curvi-linear relationship between BM and PP, the BM term for each athlete was adjusted by squaring the value (BM2). BM2 (r = 0.89) and VJ (r = 0.80) were significantly correlated with PP (p < 0.05). The new model equation, PP (W) = (0.379 x BM2) + (53.332 x VJ) - 391.107 was significantly correlated with actual peak power (r = 0.96; SEE  = 240.8 W). The actual PP generated during the VJ (3617.1 ± 433.3W) did not differ from power estimated using the novel equation (3528.0 ± 454.8W) or Sayers equation (3477.9 ± 443.0W). However, power estimated using the Harman (3133.2 ± 402.5W), and Canavan (2985.4 ± 376.2W) equations were significantly different than the actual PP (p<0.05). CONCLUSIONS: The PP estimate of the proposed model equation accurately predicts peak power in young athletes. Although slightly less accurate than the novel equation, Sayers equation estimates were not significantly different than the actual peak power. This could be due to the larger sample sizes used to model both equations. PRACTICAL APPLICATION: Strength and conditioning coaches can use the newly modeled equation to accurately predict peak power using BM and VJ in young athletes; however, more research is needed to validate this and other power estimation equations in a variety of populations. Methods VJ data were collected from two hundred and seventy (N=270) youth soccer players: two hundred and fifty five (n=255; 14.1 ± 1.8 y) were used to model the new equation and fifteen (n=15; 15.9 ± 1.1 y) were used as a validation sample. All athletes completed a general warm-up, eight dynamic stretches, and a series of jumps to prepare for maximal testing. BM was determined on each athlete before they were permitted two practice jumps on the force plate. Data were collected at 400 Hz while the subjects performed a single maximal counter movement VJ on the force plate with a wooden dowel held securely across their shoulders. Peak power (PP) and VJ height were derived from a commercial software program. A multivariate regression equation was developed using VJ and BM to predict PP using the original 255 athletes (Table 1). Using the validation sample (n= 15), the actual PP was compared to power estimated using the novel equation and three previously established equations (Table 2) (Sayers et al 1999; Harman et al. 1991; and Canavan  et al. 2004) using Repeated Measures Analysis of Variance (ANOVA). Holms-Sidak post hoc test was used for pairwise comparisons with an alpha of p <0.05. Conclusions The PP estimate of the proposed model equation (Table 1) accurately predicts peak power in young athletes. Although slightly less accurate than the novel equation, Sayers equation estimates were not significantly different than the actual peak power. This could be due to the larger sample sizes used to model both equations. Results Novel Equation PP (W) = (0.379 x BM2) + (53.332 x VJ) - 391.107 Table 1 all VJ heights measured in cm; BM measured in kg Authors Equation Sayers PP (W) = 60.7 x VJ + 45.3 x BM - 2055 Harman PP (W) = 61.9 x VJ + 36.0 x BM + 1822 Canavan PP (W) = 65.1 x VJ + 25.8 x BM - 1413.1 Introduction Expression of power in triple extension movements is a key to success in many sports. Although power can be measured directly with a force plate, several field equations using vertical jump height (VJ) and body mass (BM) have been developed to predict peak power. Generally, these previously published equations were derived from relatively small numbers (N = 17 to 108) of adults  with an average age of 22.0 years. Estimating power using these equations may not be ideal for young athletes. The purpose of this study was to develop a novel equation to estimate peak power in young athletes and to compare its accuracy against previously published equations. Table 2 Practical Applications Strength and conditioning coaches can use the newly modeled equation to accurately predict peak power using BM and VJ in young athletes; however, more research is needed to validate this and other power estimation equations in a variety of populations. References Canavan, P. K., et al. (2004). Evaluation of Power Prediction Equations: Peak Vertical Jumping Power in Women. Medicine and Science in Sports and Exercise v. 36 no. 9, p. 1589-93. Harman, E. A., et al. (1991). Estimation of Human Power Output from Vertical Jump. Journ. of Appl. Sport Sci. Research v. 5 no. 36, p. 116-120. Sayers, S. P., et al. (1999). Cross-validation of Three Power Equations. Med. Sci. Sports. Exerc. v. 31 no. 4, p. 572-577. Presented at the NSCA National Conference July 14-17, 2010 / Orlando, FL