The purpose of this study was to determine whether increased pole stiffness corresponds with higher measures of upper body power in competitive cross-country skiers. Fifteen elite/college level cross-country ski racers (8 men, 7 women) tested UBP on a custom-built double-poling ergometer. Ski poles tested were two models of the same brand with different factory-specified stiffness ratings. Subjects underwent three 10 s UBP tests (W₁₀, W) and one 60 s UBP test (W₆₀, W) for each pole type. UBP measures were defined as the average power output over the length of each test. Video recordings of the 10 s and 60 s tests were analyzed with digital imaging software to determine the maximum bend angle for each pole type. Ergometer and kinematic measures were compared by ski poles tested (stiff vs. less stiff) using a multivariate RMANOVA (α=0.05). Measures of W 10 and W 60 for stiff and less stiff poles did not differ significantly (P=0.077, 0.077). However, a post-hoc evaluation determined that men had higher W 60 values with the stiff poles (p = 0.014). Maximum poling angles were greater when using less stiff poles for both the 10 s (p = 0.003) and 60 s (p < 0.001) tests. However, a post-hoc evaluation discovered that when grouped by gender, only male subjects created greater bending with the less stiff poles (p = 0.003, P < 0.001 for 10 and 60 s tests, respectively). For both 10 and 60 s tests, Pearson’s product moment correlation coefficients were calculated between differences in pole bend (Δflex_{10, 60}) and differences in power output (ΔW_{10, 60}) as well as absolute power output (W_{10, 60}). Δflex correlated well with ΔW for both tests (r = 0.62, 0.59 for 10 s and 60 s tests). W₁₀ and W₆₀were the best predictors of pole bend in their respective tests (r = 0.86, 0.94 for 10 and 60 s tests). These findings suggest that only skiers with highest power output will be able create enough pole bending to affect measures of UBP between poles with slight differences in stiffness.