Maintenance of approach velocity despite increasing internal load during repeated pole vault attempts

Biomechanical analyses identify approach velocity-particularly in the final meters-as the primary mechanical determinant of vertical displacement in pole vault; yet how this velocity changes across repeated attempts performed below personal best height remains a practically important but largely untested question. As part of an applied field-based preparatory-phase protocol, we monitored the metabolic, cardiovascular, and perceptual responses of pole vaulters during four vault attempts performed 20 cm below their personal bests, and examined whether approach velocity was maintained in the final 5 m under these conditions. Eleven competitive pole vaulters (4 women, 7 men; age 20.3 ± 2.6 years) performed four consecutive vault attempts at heights 20 cm below their personal bests, with 3.5-4 min recovery intervals. Blood lactate (BL), heart rate (HR), and ratings of perceived exertion (RPE; Borg CR-10) were measured at predetermined time points throughout the protocol. Approach velocity and step kinematics (step length [SL], step frequency [SF], and contact time [CT]) over the final 5 m were derived from two-dimensional video analysis. Phase-related changes, load-velocity and step kinematic-velocity associations, subgroup interaction effects, and individual load change correlations were assessed using linear mixed-effects models (LMM) and Pearson correlation analyses. BL and HR showed no significant change between successive attempts (A₁-A₄; all p_Tukey > 0.05), whereas RPE increased significantly between A₃ and A₄. At A₄₍₁₁₎, neither BL nor RPE differed significantly from resting values (BL: p_Tukey = 0.375; RPE: : p_Tukey = 0.894); HR reached warm-up levels but remained significantly above rest (p_Tukey = 0.001). Approach velocity and all step parameters did not show a significant change throughout the four attempts (all p > .05). Neither exploratory model identified a significant relationship between velocity and physiological load indicators or step kinematics (all p > .05). Individual trajectory analysis revealed heterogeneity in velocity and kinematic strategies beneath the group-level mean. Subgroup interaction analyses revealed significant Attempt × Group effects for approach velocity in both the V₁ (F(3,27) = 11.80, p < .001) and V₃ (F(3,24) = 9.28, p < .001) models, with Velocity-Declining athletes demonstrating significantly greater velocity decrements at A₃ and A₄. Pole vaulters showed no detectable change in approach velocity across four consecutive attempts despite rising effort perception and progressive metabolic stress. The heterogeneity in individual kinematic strategies underscores the need for cautious interpretation of group-level findings.