title: Sprint running: how changes in step frequency affect running mechanics and leg spring behaviour at maximal speed.
abstract: The purpose of this study was to investigate the changes in selected biomechanical variables in 80-m maximal sprint runs while imposing changes in step frequency (SF) and to investigate if these adaptations differ based on gender and training level. A total of 40 athletes (10 elite men and 10 women, 10 intermediate men and 10 women) participated in this study; they were requested to perform 5 trials at maximal running speed (RS): at the self-selected frequency (SFs) and at SF ±15% and ±30%SFs. Contact time (CT) and flight time (FT) as well as step length (SL) decreased with increasing SF, while kvertincreased with it. At SFs, klegwas the lowest (a 20% decrease at ±30%SFs), while RS was the largest (a 12% decrease at ±30%SFs). Only small changes (1.5%) in maximal vertical force (Fmax) were observed as a function of SF, but maximum leg spring compression (ΔL) was largest at SFsand decreased by about 25% at ±30%SFs. Significant differences in Fmax, Δy, klegand kvertwere observed as a function of skill and gender (P < 0.001). Our results indicate that RS is optimised at SFsand that, while kvertfollows the changes in SF, klegis lowest at SFs.
authors.affiliation: a Department of Neurological, Biomedical and Movement Sciences , University of Verona , Verona , Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Monte
authors.affiliation: a Department of Neurological, Biomedical and Movement Sciences , University of Verona , Verona , Italy.
authors.forename: Valentina
authors.initials: V
authors.lastname: Muollo
authors.affiliation: a Department of Neurological, Biomedical and Movement Sciences , University of Verona , Verona , Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Nardello
authors.affiliation: a Department of Neurological, Biomedical and Movement Sciences , University of Verona , Verona , Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Zamparo
mesh_terms: D000293:Adolescent; D000328:Adult; D054874:Athletic Performance; D001696:Biomechanical Phenomena; D004548:Elasticity; D005260:Female; D005684:Gait; D005783:Gender Identity; D006801:Humans; D007866:Leg; D008297:Male; D010806:Physical Education and Training; D012420:Running; D012737:Sex Factors; D055815:Young Adult
keywords: Sprint kinematics; sprint running; step frequency variations; stiffness