The purpose of this study was to identify the effects of the aerodynamic forces, mass of the jumper-ski system (m), head wind (U_w) and initial approach velocity (V₀) on the approach velocity (U_a) in ski jumping. We measured drag area (S_D) and lift area (S_L) of approach position from the wind tunnel experiment with 44 athletes of Japanese national team (Nordic combined and Ski jumping) . To estimate the maximal initial approach velocity, we measured initial approach velocity using a laser distance measurement module in the actual jumping trials at the Hakuba normal hill. Then we calculated approach velocities by solving equations of motion with changing these parameters (S_D, S_L m, U_w and V₀) between different approach lengths in Okurayama large hill and Hakuba normal hill.

It was found that increases of S_D or U_w would reduce the U_a. Furthermore, relatively small m could reinforce these effects of S_D and U_w on the reductions of U_a. On the other hand, a given increase of V₀ made a constant increase of U_a regardless of the variations of parameters of m, S_D and approach length. These results indicate that the importance of the improvement of start technique as much as approach position for maximizing approach velocity.