Science and Steep Seat Angles
A version of this article was originally
published in Triathlete Magazine
Over the years, articles in Triathlete have expressed various, and sometimes conflicting, opinions on optimal saddle fore-aft position/seat tube angle. The differing hype of manufacturers, bike shop staff, post-race transition area gurus and the like have added to the mystery. Has there been any sound research about the merit of steep (e.g. 78°) vs. less radical (e.g. 74°) seat tube angles across the various race course lengths (sprint, Olympic, Ironman, etc.); particularly in light of the demands of the run that the we face once out of T-2? I appreciate that individual assessment might answer the question best, but what general findings would wisely guide the triathlete (in their quest for moh speed).
Port Coquitlam, British Columbia
You are right, this is a question that has many conflicting points of view within the industry. I suspect this is because there has been relatively little scientific study completed and published and because the UCI (professional cycling’s international governing body) forces pro road riders to ride in slack seat angle time trial positions (usually 74° or less) that keep the nose of the saddle 5cm or more behind the center of the crank. This UCI ruling does not effect triathletes at all, but has confused the issue because the fastest cyclists on earth are often looked to as guides by many amateur athletes and bike shop personnel, who don’t always realize that pro cyclists may not be allowed to ride in their most efficient position because of a rule.
I am not aware of any scientific study on Ironman distances. There have been studies done at shorter distances that indicate that a more forward position is beneficial to the majority of riders. How sound these studies are is a bit more questionable. The most sited study was completed by Garside and Doran in 2000, and published in the Journal of Sports Sciences, #18. This laboratory study was performed on eight male triathletes in Britain who usually rode slacker (73 degree) seat angle positions. The athletes performed a counterbalanced 40km ride at 73 degrees and also at 81 degrees. They followed each ride with a self-paced 10km run. The findings showed that cycling times over the 40km were, on the average, 1:16 faster in the forward position and a very notable 2:34 faster in the first 5km of the run with the more forward 81 degree position. Time differences in the second 5km were less pronounced. Overall, the athletes finished the complete test an average of 4:44 faster in the more forward position.
Before assuming that a more forward seat angle is better for you based on these results, keep in mind that this study, and others like it, have some significant compromises in their scientific method that could alter your experience in the real world. For example, the Garside study was completed indoors on a single stationary bike. There is no indication that important variables like saddle height or the length of the cockpit were changed between the two seat angles tested. The study only mentioned the seat angle and handlebar height as being adjusted and it is unlikely that a proper fit for each subject was able to be obtained in either position. It also does not speak of aerobars being used; which indicates that the athletes were probably not riding in a true aero position, but were instead just riding in a more forward and upright position during the tests. Furthermore, the athletes were limited to riding at 70% of their maximum VO2 – which may not duplicate a true race scenario. How does this all effect the results? It is impossible to tell without doing a more controlled study, but the implications are certainly worth thinking about.
This being said, my experience doing computer based Performance Analysis fittings with a broad range of athletes supports many of the results from the studies. If you don’t have any limiting factors that would keep you from being able to hold a position, a more forward position is most likely going to be your most efficient in a triathlon. Why? The hypothesis is that a more forward seat position encourages the hamstrings and gluteus muscles to be recruited more readily than a slacker seat angle. This encourages more balanced muscle recruitment during pedaling by taking some dependency off the psoas and quadriceps while riding. This can help preserve these muscles, allowing them to remain fresher for the difficult biomechanical and physiological adjustment period that is inherent in the transition from cycling to running.
For every rule, there are exceptions. Individual circumstances, background and physical limitations must be taken into account when building a cycling position as comfort and being able to hold a position are both fundamental to a position’s effectiveness. The geography of your focal event should also be taken into account as it is very unlikely that the winner at the Mount Washington or Mount Evans time trial will be riding in a forward aero position anytime soon. If you want to know for sure what is most efficient for you, locate a professional fitter who has the capacity to asses your position from an individual and scientific perspective. Making such changes over the winter is a great time to be completely ready for the coming season.
Originally published January 2003/Copyright © 2003