Staying Fast

There are few endurance sports that demand speed and explosiveness quite like bicycle road racing.  Not only do many road races end up in sprint finishes, there are numerous occasions during most events where attacks determine the make up of the final winning finishing group.  So, not only must a road racer possess the endurance to make it to the finish, he or she must possess the speed and power to make the break and finish fast.  Yeah, so?

Well, the majority of cycling training involves riding for long periods of time.  Success in the sport demands big miles.  Can't get around it.  Typically, all things being equal, the more miles you have in your legs from training, the better your chances are for making it to the finish.  But once you find yourself headed for the finish in the lead group, what then?  Can you sprint?  Do you have the jump, the explosive acceleration required to distance yourself from the others and win?  Maybe not.  Why not?

Being able to accelerate quickly on a bike is determined by several factors.  First off is our genetic make up, something we have little control over currently (genetic engineering/doping may change that in the future).  At the biomolecular level, each athlete possesses an innate and unique combination of fast (type IIa/IIb) and slow twitch (type I) muscle fibers.  Most "average" individuals possess equal amounts of both.  However, champions in particular sports find themselves heavy on the fiber types that benefit them most in their chosen sport.  Sprinters and weight lifters usually have a greater percentage of fast twitch fibers that provide them the speed and explosiveness to excel at their sport.  Endurance athletes, on the other hand, do better because they have more slow twitch fibers.

Here lies the rub with road cycling:  You need a lot of Type I fibers to make it to the finish but that same quality ends up hanging on you like a boat anchor when it comes time to sprint for the win.  Short of genetic engineering, is there any way to improve your odds if you come from the predominately slow twitch end of the gene pool?  In a word, yes!  You see, top level endurance athletes have a lot of slow twitch fibers going for them but that does not mean they have no fast twitch fibers.  On the contrary, the Type IIa/b fibers are there but, unless trained for the task, don't get much attention.  Interestingly, fail to pay attention to them and they start acting like slow twitch fibers, particularly the type IIa fibers.  WHAT!?  Yeah, that's right, with the right (or wrong) kind of training (endurance) we can take our normally Type IIa fibers and get them to throw down with the rest of the Type I fibers.  In other words, they start acting out of character.  Adding to this unfortunate development is that with lots of endurance training those type I fibers will actually shrink in size as they become increasingly efficient.  Now, that's great for getting to the finish but it's a poor use of resources if you want to sprint for the win.  What to do?

With proper training we can make the most out of what Type IIa/b fibers we possess and improve our chances when crunch time comes.  Getting our fast twitch fibers to do their thing is mostly a neurological task, meaning that we must "demand" their participation.  There are only two situations where these fibers will "listen" to our demands.  The first is moving really heavy loads or resistances.  Muscle fibers are recruited sequentially by demand.  With light loads, Type I fibers are all we need.  Try to move something really heavy and the Type II fibers get involved.  The other situation has to do with speed.  The faster we try to move, the more likely the Type II fibers will get involved.

These two facts have significant implications for training structure.  If you want to win or make the break, you have to do speed work.  This is obvious for most.  Train your sprint.  Spend at least one training day per week working on this.  But is there more to it than just sprinting to the next speed limit sign on training rides?  Definitely.  Understanding the physiology of these fast fibers will help guide the design of these workouts.

As I stated above, to get these fibers fired up takes either great force or high speed.  You have to be motivated during these sessions.  Their other quality that needs to be considered is that these fibers fatigue quickly.  What that means is that these workouts require you to be as fresh as possible at the start of each work interval.  The more loaded up you are heading into the training sprint the less likely you are to recruit the target fibers.  Yes, in races things will be different but in training you want to get these guys on board the best way possible.  Keep it short, push hard, turn it over as fast as possible and then get plenty of recovery between efforts. 

There is one more subtle distinction here.  I said to turn it over as fast as possible.  That does not mean you have to warp it out at 150 rpm.  In a big gear, most riders will not be able to do this.  The important thing is that you try to warp it out.  It is this neurological demand for speed and force that brings the Type II fibers to bear.  It's all about intention.

Next, I will talk about training techniques off the bike that may improve on the bike sprint performance.  - Brian