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The effect of Q F actor on gross mechanical efficiency and muscular activation in cycling
Author(s) -
Disley B. X.,
Li F.X.
Publication year - 2014
Publication title -
scandinavian journal of medicine and science in sports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.575
H-Index - 115
eISSN - 1600-0838
pISSN - 0905-7188
DOI - 10.1111/j.1600-0838.2012.01479.x
Subject(s) - vastus medialis , cycling , electromyography , lower limb , physical medicine and rehabilitation , medicine , chemistry , surgery , archaeology , history
Unexplored in scientific literature, Q F actor describes the horizontal width between bicycle pedals and determines where the foot is laterally positioned throughout the pedal stroke. The aim of the study was to determine whether changing Q F actor has a beneficial effect upon cycling efficiency and muscular activation. A total of 24 trained cyclists (11 men, 13 women; VO 2max 57.5 ml·kg/min ± 6.1) pedaled at 60% of peak power output for 5 min at 90 rpm using Q F actors of 90, 120, 150, and 180 mm. Power output and gas were collected and muscular activity of the gastrocnemius medialis ( GM ), tibialis anterior ( TA ), vastus medialis ( VM ), and vastus lateralis ( VL ) measured using surface electromyography. There was a significant increase ( P < 0.006) in gross mechanical efficiency ( GME ) for 90 and 120 mm (both 19.38%) compared with 150 and 180 mm (19.09% and 19.05%), representing an increase in external mechanical work performed of approximately 4–5 W (1.5–2.0%) at submaximal power outputs. There was no significant difference in the level of activity or timing of activation of the GM , TA , VM , and VL between Q F actors. Other muscles used in cycling, and possibly an improved application of force during the pedal stroke may play a role in the observed increase in GME with narrower Q F actors.