Effects of saddle height on muscular pattern and interlimb coordination in cycling

Philippe Dedieu (1) , Marine Pelaez (2) , Éric Poirier (3) , Pier-Giorgio Zanone (4)

1 PSMS - Performance, Santé, Métrologie, Société - EA 7507
2 IRFSS Nouvelle-Aquitaine
3 Medicapteurs [Toulouse]
4 CERCO - Centre de recherche cerveau et cognition

Purpose: In the face of empiricism prevailing to set an ideal position in cycling, the present study aims to find whether interlimb coordination and muscular activation patterns would provide relevant parameters to characterise an optimal saddle height. Methods: Eighteen experimented bikers were asked to pedal at a rate of 90 rpm under three randomized experimental conditions: Usual Saddle Height (USH), Saddle Height plus (SHP) (leg fully extended, pedal down, ankle in a neutral position) and Saddle Height minus (SHM) (same saddle height difference applied inversely). From the 3D coordinates, the kinematics of ankle, knee and hip were computed and the relative phase between the joints periodic motion was assessed through a Continuous Relative Phase (CRP) algorithm. Muscular activity was recorded through a surface EMG system. Results: While the hip, the knee, and the ankle range of motion were affected by saddle height changes, CRP highlights modifications in interjoint coordination, particularly between ankle and knee and ankle and hip, indicating significant tendency to an in-phase coordination for the experimental conditions compared to the USH condition. Conclusions: Whereas saddle height changes affect joint kinematics and muscular patterns, the freeing of neuro-muscular degrees of freedom in the USH condition allows motor output to adapt dynamically during its very execution. Results suggest that interjoint coordination is an integrative variable providing a relevant parameter to define a correct saddle height in cycling. To reach an ideal cycling position, it may help avoiding the deleterious and painful consequences of a cyclist's inadequate position.

Mots clés: saddle height; coordination; muscular pattern; cycling position

Domaines: Biomécanique [physics.med-ph]; Neurosciences [q-bio.NC]

Philippe Dedieu, Marine Pelaez, Éric Poirier, Pier-Giorgio Zanone. Effects of saddle height on muscular pattern and interlimb coordination in cycling. Citius Altius Fortius – Journal of Physical Education and Sport, 2020, 20 (1), pp.222-228. ⟨10.7752/jpes.2020.01029⟩. ⟨hal-03015668⟩