Faster cycling: pick your gears
By Dave Scott
Dec. 6, 2006 -- Prior to the 1984 Ironman a fellow competitor came up to me and proclaimed that he rode the previo us Ironman maintaining an average of 60 RPM's throughout the race. Astonished by his slow turnover, I asked him if he felt comfortable and efficient while pushing such large gears. (He had a 60 inch front chain ring specially built for his bike.) Without reservation he said that he was most economical riding in "huge" gears.
Quickly assessing his performance I soon realized that he wasn't on the top-ten leader board but still was intrigued by his selection and ability to ride at such a slow cadence.
Over 20 years has passed since this "big gear encounter" and mountains of technical studies and practical application has determined that 60 RPM's is not the optimal number! After perusing the scientific studies, I found nearly twenty-five articles on gearing. The common consensus for cycling cadence is 90 RPM's +/- 5. The 85-95 RPM range is seemingly optimal to maintain sustained power output. The first question that all of us wrestle with is whether we can maintain this cadence in the BIGGEST gear for the entire length of your race. I'll address this question is a minute.
The two other questions that will optimize your cycling speed are: 1) can I condition my muscles to generate more force and 2) are there specific training principles that I can adopt to enhance my performance. In order to answer these questions, I'll unravel some of the specifics about muscles, fiber type, crank length and the ability to run off the bike.
Muscle fibers
Every endurance athlete understands the concept of a slow or fast twitch fiber. There is also an intermediate fiber that can take on the contractile potential of either the slow or fast fibers, depending on the training protocol. Simply, they can assist the slow twitch when there is more force required on the pedal stroke.
When you exert force on the pedal a single nerve pulse is sent to the fibers to accommodate the load. The slow twitch fibers are predominately aerobic but are still activated even under sprinting conditions. That one single nerve controls these fibers. The fibers and nerve are called motor units. As the force increases more motor units are recruited. These are the intermediate and fast twitch fibers.
Interestingly as the cadence increases the predominant fiber is the slow twitch. What distinguished the fiber selection is the force. Once the slowtwitch reach their optimal contractile force then they call on more motor units, predominately the other two types of fibers.
So why are the muscle fiber types important? Most of us will never have a biopsy done to determine the percentage of slow and fast twitch muscle fibers. We are primarily concerned with the end result, going faster. The fibers are genetically programmed by our parents. We cannot alter the genetic composition of fibers with the exception of a small percentage that will split and duplicate under intense training. How we train, the type of endurance and power that we develop determines our ability to optimally enhance our muscular system.
Training the fiber types and specifically the intermediate fiber is critical for all triathletes, sprint to Ironman.
A training concept called training specificity states that the training sessions must replicate the sport and training workloads. However in order to create the stimulus within the muscle fiber ultimately enhancing the recruitment, reducing O2 consumption and limiting lactate production, you need to incorporate variable gearing.
Variable gearing
On every route that you ride whether it is done aerobically or near threshold, instinctively you will gravitate to the gear selection that limits the muscle strain. This muscle fiber accommodation is developed over months and years of discipline and training. To differentiate the subtle recruitment a variable gearing training should be implemented.
Select larger gear (1cog up) and ride your flats, hills and time trial courses in a slightly larger gear. Maintain a cadence within 65-84 RPM's. Insert segments of 30 seconds to three minutes within your rides, either as repeats or a percentage of total time.
Note your speed, perceived exertion, heart rate and power output. Contrast and compare your select routes with your 'normal' gearing.
By elevation, the recruitment package will stimulate the muscle fibers that will provide the extra force under stress. Seasonal conditioning using variable gearing should be intermixed throughout the year. As the season progresses and the fitness improve, your ability to "recruit" will be heightened.
Crank length
Shortening the crank length will initially feel as though your power output is reduced. The muscles will take 3 to 6 weeks to adapt to a shorter circumference and ultimately your cadence will go up. Remember, the perception of muscle load and production of lactic acids should diminish if you maintain the 85-95 RPM range. If you have a slower cadence, selection of smaller gears is your first choice and secondly possibly shortening your crank arm may positively influence your cadence.
Pedaling style and triathlon racing
Efficient runners have a cadence of 88-96 RPM. This turnover rate coincides with the optimal cycling RPM. The muscle accommodation elicited by cycling compliments optimal running. So it makes sense to maintain the discussed cycling RPM.
Athletes with slower cadence layer gears have been able to produce higher gross power outputs. However, even in sprint races (20 KM in cycling) require the ability to maintain the highest possible output over a longer time period. The physiological systems would completely exhaust themselves by prematurely firing all of the fast twitch fibers if the gearing is too high and the cadence too slow. Muscle glycogen and lactic acid production would prohibit the ability to maintain speed.
If you are a slow cadence, big gear person, try variable gearing by selecting smaller (easier) gears. Practice your training courses with a higher spin and note the factors mentioned previously.
Pedaling style can also affect your ability to run by the style of riding during climbing. In any world-class cycling or triathlon race there are contrasting styles during the climbs. Maintaining a seated position throughout all climbs is no the most effective choice for triathletes. Remember we have to run off the bike. Stretching out your hamstrings, low back and glutes by standing periodically will remind your torso of the running position. Don't be caught up in a fast uphill spin, stand up five to thirty seconds and change the anatomical position and alter muscle recruitment.
Gearing is individual but there are training practices that can be weaved into your program. Be flexible in your approach into the 2007 season. Tweak your training, alter your gearing and you'll reap the rewards.