First we need to talk about what each type of muscle fibers are and how they work. Slow twitch fibers are also known as type 1 fiber. They are better at using oxygen to create fuel known as Adenosine Tri- Phosphate (ATP), or glucose fuel for continuous muscle contraction used over a long time. They fire off slower than fast twitch fibers and can be used better over long periods of time. I would guess that Fabian Cancellara has a more dominate slow twitch natural physical build, with his long Time Trial abilities. Fast twitch fibers are also known as type 2 muscle fibers and can be broken down into two parts, (type 2 A and type 2 B). Type 2 fibers are better used in anaerobic metabolism to create ATP. Since none of us can be anaerobic for long extended periods of time, fast twitch fibers fatigue more quickly than slow twitch fibers. However they fire off at a rapid rate and that is why they are called Fast twitch fibers. Fast twitch, type A, fibers are intermediate and can be used both aerobically and in anaerobic zones, while cycling and creating ATP. Really are both type 1 and 2 fibers working in combination with each other. Finally Fast twitch type 2 B fibers are most likely seen in short powerful burst. The short efforts are usually anaerobic and are best described as the moment when a road racer starts his sprint, in an entire BMX race, or when a road rider is breaking away from the pack. I would guess that riders like Luke Keough, Rahsaan Bahati, BMX super star Conner Fields, and world track star Lee Wai Sze have natural fast twitch abilities.
Although athletes, at high levels of competition, tend to already be in the correct discipline for their type of natural ability and fiber usage, these aspects can always be trained. For instance, a track sprinter will also need to train endurance and slow twitch fibers. An iron man triathlete should also train their fast twitch fibers at some point, for the explosive parts of the course. Fibers alone can’t determine whether or not an athlete is elite or not. Really there are so many variables determining how good an athlete is, it is unreal. Don’t forget about my main focus of heart. Athletes with heart and drive tend to stomp a lot of the talk about natural ability out.
So how does the average Joe cyclist train their unnatural ability to expand to what is more natural for them? Let’s face it, if you’re a road racer you need to use all the aspects of both your fast twitch and slow twitch muscle fibers. You know when a rider says I just don’t have that pop yet in my training, or a rider might say I fatigue after a long grinded out ride, muscle fibers are basically what they are describing. With sports conditioning slow twitch fibers are trained during endurance paced/efforts. So that is easy, but to do that with power is different. Natural resistance training plans are welcomed for that also. Now fast twitch fiber, in my opinion, is best trained on the bike with short sprint efforts and sprint build ups. Off the bike, what I like to call fast twitch plyometric exercises are awesome ways to improve your fast twitch performances. Some exercises like jumping rope in sets of a few minutes at a time in a fast “boxing style”. Step-ups on a box in 30-40 second sets and also super fast can help these fibers fire off better. Light weight or lighter weight low rep weight training can help your fast twitch. The possibilities are endless. I like to play fast twitch hop scotch and run stairs. These are just some fun ways to keep your training interesting. A good coach will know your medical history and prescribe on and off the bike workouts to suite your needs. If a coach ever just tells you to go to the gym for a workout, hire a new coach or a personal trainer to coincide with your coaching. If a cycling coach ever gives you a workout that simply says ride for an hour, you might want to go with a different person. If you have knee issues and your trainer/coach is telling you to do box jumps all the time, then that can be an issue. If you have back issues and the trainer wants you to do squats all the time then this can be an issue. My point is when making plans for each specific individual athlete, coaches/trainers need to know all about that person and respect those needs.
I hope this has helped shed some light on the whole fast twitch needs to be trained more conversation. So next time a rider says cycling is a fast twitch sport while on a long slow century charity ride, we can raise our eye brow and say really, what are we really training right now?
Kevin Lee- USAC coach/personal trainer