The Influence of Bicycle Geometry on Time-Trial Positioning Kinematics and Markers of Performance
- Aerodynamic drag,
- Body position,
Copyright (c) 2019 International Journal of Physical Education, Fitness and Sports
This work is licensed under a Creative Commons Attribution 4.0 International License.
Studies have previously documented how changes in cycling body kinematics are related to submaximal energetics and power output, as well as cycling performance, but few have focused specifically on how body kinematics will vary with changes in bicycle geometry. This study sought to describe kinematic changes resulting from the systematic change of several bicycle geometry variables: Trunk angle (“low” and “high” positions), seat-tube angle (76° and 80°), saddle tilt angle (0° to -10°), saddle sitting position (middle or nose), as well as two types of saddles. Methods: Well-trained cyclists were kinematically evaluated across specific combinations of geometry variables using a modified cycle ergometer at a standard relative power. Standard two-dimensional sagittal-view kinematics from the left side were used to summarize a collection of kinematic variables: Trunk angle, hip angle (HA), knee angle, pelvic tilt angle, and two “composite” angles called body position and pelvic position (PP). Finally, each trial was also evaluated for frontal area (FA; m2) from stationary digital photography. Data were evaluated using repeated measures ANOVA (a=0.05) to evaluate change in kinematics between trials, as well as regression analysis to determine predictability of performance markers (HA and FA) from the collection of geometry and kinematic variables. Results: Changing trunk angle had the greatest impact on other kinematic variables, while saddle type had no influence. Regression showed that geometry variables could explain 75-85% of the variability in either HA or FA, while 78-79% of the variation in HA and 83-84% of FA was explained by PP alone. Conclusions: The composite kinematic measure PP was generally a better predictor of both HA and FA than any combination of geometry variables. These results can serve as a starting point for understanding the interactions between bicycle geometry and body kinematics, both of which are important determinants of power generation and aerodynamic drag.
- D.P. Heil, Body size as a determinant of the one-hour cycling record at sea level and altitude, European Journal of Applied Physiology, 93 (2004) 547-554.
- T.S. Olds, K. Norton, N. Craig, S. Olive, E. Lowe, The limits of possible: models of power supply and demand in cycling, Australian Journal of Science and Medicine in Sport, 27 (1995) 29-33.
- J. Vrints, E. Koninckx, M. Van Leemputte, I. Jonkers, The effect of saddle position on maximal power output and moment generating capacity of lower limb muscles during isokinetic cycling, Journal of Applied Biomechanics, 27 (2011) 1-7.
- O. Inbar, R. Dotan, T. Trousil, Z. Dvir, The effect of bicycle crank-length variation upon power performance, Ergonomics, 26 (1983) 139-1146.
- J.C. Martin, W.W. Spirduso, Determinants of maximal cycling power: crank length, pedaling rate and pedal speed, European Journal of Applied Physiology, 84(5) (2001) 413-418.
- J.C. Martin, R.M. Malina, W.W. Spirduso, Effects of crank length on maximal cycling power and optimal pedaling rate of boys aged 8-11 years, European Journal of Applied Physiology, 86 (2002) 215-217.
- S. Buscemi, B. Canino, F. Dagnese, F.P. Carpes, V. Caladrino, C. Buscemi, A. Mattina, S. Verga, Influence of a new bicycle crank design on aerobic parameters of non-cyclists, Journal of Sports Medicine and Physical Fitness, 52 (2012) 47-52.
- F.P. Carpes, F. Dagnese, C.B. Mota, D.J. Stefanyshyn, Cycling with noncircular chainrink system changes the three-dimensional kinematics of the lower limbs, Sports Biomechanics, 8 (2009) 275-283.
- D.P. Heil, A. Wilcox, C. Quinn, The effect of seat-tube angle variation on cardiorespiratory responses during submaximal bicycling, Medicine and Science in Sports and Exercise, 27 (1995) 730-735.
- D.P. Heil, T.R. Derrick, S. Whittlesey, The relationship between preferred and optimal positioning during submaximal cycle ergometry, European Journal of Applied Physiology, 75 (1997) 160-165.
- D. Price, B. Donne, Effect of variation in seat tube angle at different seat heights on submaximal cycling performance in man, Journal of Sports Sciences, 15 (1997) 395-402.
- E. Bressel, B.J. Larson, Bicycle seat designs and their effect on pelvic angle, trunk angle, and comfort, Medicine and Science in Sports and Exercise, 35 (2003) 327-332.
- I.R. Spears, N.K. Cummins, Z. Brenchley, C. Donohue, C. Turnbull, S. Burton, G.A. Macho, The effect of saddle design on stresses in the perineum during cycling, Medicine and Science in Sports and Exercise, 35 (2003) 1620-1625.
- M.C. Ashe, G.C. Scroop, P.I. Frisken, C.A. Amery, M.A. Wilkins, K.M. Khan, Body position affects performance in untrained cyclists, British Journal of Sports Medicine, 37 (2003) 441-444.
- M.J. Berry, W.E. Pollock, K. van Nieuwenhuizen, P.H. Brubaker, A comparison between aero and standard racing handlebars during prolonged exercise, International Journal of Sports Medicine, 15 (1994) 16-20.
- R.C. Browning, R.J. Gregor, J.P. Broker, Lower extremity kinetics in elite athletes in aerodynamic cycling positions, Medicine Science in Sports and Exercise, 24 (1992) S186.
- F.J. Diaz, C.H. Dix, C. Frazer, Maximal and submaximal exercise in different position, Medicine and Science in Sports and Exercise, 10 (1978) 214-217.
- S. Dorel, A. Couturier, F. Hug, Influence of different racing positions on mechanical and eletromyographic patterns during pedalling, Scandinavian Journal of Medicine and Science in Sports, 19 (2009) 44-54.
- Faria, C. Dix, C. Frazer, Effect of body position during cycling on heart rate, pulmonary ventilation, oxygen uptake and work output, Journal of Sports Medicine and Physical Fitness, 18 (1978) 49-56.
- Garside, D.A. Doran, Effects of bicycle frame ergonomics on triathlon 10-Km running performance, Journal of Sports Sciences, 18 (2000) 825-833.
- P. Gnehm, S. Reichenback, E. Altpeter, H. Widmer, H. Hoppeler, Influence of different racing positions on metabolic cost in elite cyclists, Medicine and Science in Sports and Exercise, 29(6) (1997) 818-823.
- F. Grappe, R. Candau, T. Busso, J.D. Rouillon, Effect of cycling position on ventilatory and metabolic variables, International Journal of Sports Medicine, 19 (1998) 336-341.
- M.M. Origenes, S.E. Blank, R.B. Schoene, Exercise ventilatory response to upright and aero-posture cycling, Medicine and Science in Sports and Exercise, 25 (1993) 608-612.
- R.S. Richardson, S.C. Johnson, The effect of aerodynamic handlebars on oxygen consumption while cycling at a constant speed, Ergonomics, 37(5) (1994) 859-863.
- T.W. Ryschon, J. Stray-Gundersen, The effect of body position on the energy cost of cycling, Medicine and Science in Sports and Exercise, 23 (1991) 949-953.
- E. Welbergen, L.P.V.M. Clijsen, The influence of body position of maximal performance in cycling, European Journal of Applied Physiology, 61 (1990) 138-142.
- D.P. Heil, Body mass scaling of projected frontal area in competitive cyclists, European Journal of Applied Physiology, 85 (2001) 358-366.
- D.P. Heil, Body mass scaling of frontal area in competitive cyclists without aerobars, European Journal of Applied Physiology, 87 (2002) 520-528.
- D. Hawkins, M.L. Hull, A method for determining lower extremity muscle-tendon lengths during flexion/extension movements, Journal of Biomechanics, 23 (1990) 487-494.