Average Power Estimation in the 15 s Repeated Jump Test: A Comparison of the Bosco, MG, and MGM-15 Models with an Exploratory BikeErg Benchmark

Background: Average power in repeated vertical jump tests is commonly estimated rather than directly measured, and the equation chosen may substantially affect interpretation. This quasi-experimental within-subject study compared Bosco, MG, and MGM-15 estimates from identical 15 s repeated-jump kinematic data and, as a supplementary exploratory component, quantified their differences relative to power from a separate 20 s Concept2 BikeErg trial. Methods: Fifty-one physically active male participants performed a 15 s repeated vertical jump test with arm swing on OptoJump. Raw kinematic data were converted to average power using the Bosco, MG, and MGM-15 equations. Average power was also recorded during a 20 s maximal BikeErg trial. Repeated-measures ANOVA, Pearson correlations, linear regression, and Bland–Altman analyses quantified between-method and cross-task differences. Results: Mean power differed markedly across models: 40.79 ± 7.65 W/kg (Bosco), 21.60 ± 5.13 W/kg (MG), and 4.20 ± 0.54 W/kg (MGM-15), versus 7.83 ± 0.94 W/kg for BikeErg (F(1.03, 51.29) = 1082.05, p < 0.001, η2p = 0.956). MGM-15 correlated strongly with Bosco (r = 0.977) but produced substantially lower estimates. Bland–Altman mean differences relative to BikeErg were +32.96 W/kg (95% LoA: 18.69 to 47.22) for Bosco, +13.77 W/kg (4.34 to 23.20) for MG, and −3.63 W/kg (−5.27 to −2.00) for MGM-15; proportional bias was confirmed for all three models (all p < 0.001). Conclusions: Average power values from this test are strongly model dependent. Bosco, MG, and MGM-15 values are not interchangeable, even if they come from the same kinematic dataset. MGM-15 yielded estimates nearer to BikeErg power than either Bosco or MG. However, since cycling and jumping are biomechanically different activities performed over different time spans, this indicates only exploratory numerical convergence, not criterion validity.