Friday, December 7, 2007

Power Demands of Cyclocross Racing: Part 3

The cyclocross season is now over for many of us. For those going to Nationals in Kansas City there is one more week before the cross bikes get hung up on the hooks for the winter (that is, unless you are planning on going to World's). Coach Mike Kuhn and I had a great time going to cross races this season in the PA Series, the MAC series and the two USGPs in Trenton. With the help of Cycle-Ops, we were able to provide 10 trainers for riders to warm up on under the shelter of our tents. We were also able to get some racers to demo some sweet PowerTap 2.4 wireless wheels in their races. We were pleased to see that the wheels look good as new even after some serious abuse and riding in extreme conditions. These riders also provided us with some valuable data about the demands of cross racing.

In the first part of this series, I listed the summary data for a number of riders riding in the same race (Spring Mountain Cross). The power files we collected showed how cyclocross is extremely non-steady state, meaning that there are huge spikes in power followed by periods of zero power (while the rider is coasting, braking or running) and low power (while the rider is soft pedaling through technical sections). I theorized that the more technically proficient riders were able to spend more time pedaling, less time coasting and braking and they applied less braking force. This meant that they did not slow down as much and in turn did not have to make as much of an effort to re-accelerate. As evidence of this, the riders that performed better typically spent less time at sub-maximal power levels (defined as power outputs greater than 5.5 watts/kg) and had more "in the tank" at the end of the race to make an attack, follow an attack or close the gap on the rider in front.

Don't make the mistake that cyclocross, or any type of bike racing for that matter, is simply a matter of numbers. Certainly, riders that are more technically proficient are able conserve better and use their power when they need it most. This hardly means that the race is a lock though. The great thing about bike racing is that given the right circumstances, any rider may have the opportunity to win. The key for each rider is to design their training and race tactics well in order to have the greatest odds of success. In doing this, the power meter can be a very useful tool.

Let me give a few case studies of riders from different backgrounds, strengths and weaknesses to illustrate how we might put together a training plan and a race strategy tailored to each individual:

Dave: 25 year old endurance mountain bike racer. Dave did a few cross races last year but this year is making cross an equal priority. Dave's bike handling skills are fantastic, though he does not have much experience riding a cross bike and doing cross-specific things such as barriers and run-ups. Dave is 5'10" and 143 lbs. His Functional Threshold Power is 290 watts, 5 second mean maximal power (MMP) is 900 watts, his 1 minute MMP is 430 watts and his 5 minute MMP is 330 watts.

Kurt: 28 year old Cat. 1 road racer. He specializes in shorter road races and criteriums. Kurt is new to cyclocross and is treating it as an afterthought to the road season with no real ambitions except to have fun and improve his technical skills. He does not have a mountain bike and has never really spent any time riding off-road. Kurt is 6'0" and 168 lbs. His Functional Threshold power is 320, his 5 sec. MMP is 1500 watts, his 1 minute MMP is 700 watts and his 5 minute MMP is 450 watts.

Bob: 40 year old recreational rider/Cat. 5 road racer. He did a few road races last year but decided to give cross a try because he likes the laid back atmosphere. Although he loves to do group rides on weekends, he feels a bit intimidated by the pack aspect of road races. Bob owns a mountain bike and rides it occasionally but has never raced it. Bob is 5'10" and 180 lbs. His Functional Threshold Power is 275, his 5 sec. MMP is 1000 watts, his 1 minute MMP is 500 watts and his 5 minute MMP is 330 watts.

Let's start with Dave. Being an endurance mountain biker, Dave surely does not need to work on his endurance, especially to prepare for a 1 hour event. Likewise, his handling skills are very good so he will probably pick up the cross specific skills very quickly. For someone like Dave, the best way to do this is to get some experience in races and to do a course-simulation workout at least once a week. As cross has grown in popularity, many areas offer cross specific workouts where you will ride a short course with a group. If you do not live in an area with one of these sessions, you can find a local park or field and set up a short cross course (1.5-2 minutes) that includes some turns, some off-camber sections and 1-2 dismounts. Complete 4-6 repetitions of 2 laps "on", 1 lap "off". It is nice to vary the course each week to include different elements that you may encounter in races, such as sand, gravel, stairs, etc. After the ride, it is useful to download your power data and record average power and lap times for each lap. As a rider gains more experience, he should be able to choose his lines better and take the technical sections faster. However, with fatigue he may not be capable of producing as much power as the workout progresses, provided the "on" laps are really all out efforts.

Dave will clearly have difficulty making the hard accelerations that occur many times in cross races. In terms of race strategy, Dave will fair much better if he can ride in the front of a group. This will allow him to choose better lines and take the technical sections at speed instead riding behind less technically proficient riders and having to slow down and then sprint out of every turn. Riders behind him will not be able to take these sections as fast and will still have to make those jumps, which will wear them down. That said, Dave needs to get in front to begin with, to do that he needs to improve his sprint. It would benefit Dave to practice some cyclocross starts. To do these, you start with one foot down and then clip in as quickly as possible, go all out for 2 minutes and then settle into a pace that is just above functional threshold power for an additional 3 minutes. Although no cross race will have 5 minute periods of sustained power, this will help Dave practice the start of the race as well as improve his upper-end aerobic capacity. With practice, he should start to see the his power for the initial 2 minutes rise considerably.

Kurt is a very different case. His numbers indicate that he should be able to start well and get up to the front of the pack quickly. However, his lack of technical skills will make it more difficult on him than many other riders and he will get worn down throughout the race because he will decellerate more, and thereby have to accelerate much harder. The most important thing for Kurt is to get used to riding off road. Buying or borrowing a mountain bike and riding the trails once or twice a week could be of great benefit to him, and it could also be a fun way to maintain his endurance. If he is unable to get a mountain bike, riding his cross bike on some mountain bike trails can be equally and often even more beneficial. Because a cross bike has no suspension, you have to pick your lines very carefully. In sections that are too technical to ride, pick up the bike and run it. If you have a choice of trails, try to find terrain with a lot of twists and turns and avoid overly rocky sections, as they are unlike anything you would encounter in a cross race. Of course, use caution when doing these rides because there is little room for error when you are riding with no suspension. For more cross specific work, Kurt should also look for a weekly group cross workout. He should spend extra time working on skills such as dismounts and remounts, off-camber cornering and riding over loose surfaces. When riding off-road, look for low power averages and non-steady state power output. As you get more comfortable, try to spend more time pedaling and less time coasting or braking, which will result in higher power averages for the same relative level of exertion.

Like Dave, Kurt will want to ride in the front of his group if possible. Since he can accelerate faster than most others, he can use this to his advantage if he is in front because everyone behind him will also have to slow down more and re-accelerate harder. Riding like this could be a death sentence to a rider like Kurt. If you are worried that this type of riding will break the rules of cycling etiquette, don't be. Remember, it's a race!

Since Bob is not an experienced racer, he will have to build more general fitness than either Dave or Kurt. Although his races will last only 30-40 minutes, it is still important for him to develop his endurance by completing at least 1 longer endurance ride (2+ hours) every week. In cross season, this is best done on a cross bike because it will help you get more comfortable on the bike. If you have access to fire roads or dirt roads, riding on this kind of terrain can be ideal. As far as cross specific fitness goes, it is very likely that Bob needs to improve his ability to make repeated sprints. An excellent workout for this is a cross version of suicide drills. Anyone who has played basketball knows what I am talking about here, but for those that weren't subjected to that torture in 5th grade gym class, suicide drills are where you run as fast as you can to the foul line, turn around, run back, then sprint to the half court line, then back, then to the far foul line then back, etc... For cross, you can do these on a soccer or football field at 30, 50, 70 and 100 yards. Sprint as hard as you can off the line and make a quick 180 at the line, trying to turn in as small of a radius as possible. Make sure that you don't get bogged down in you gear and you are sprinting all out after each line. Complete 4-8 sets of these with 5 minutes recovery in between sets. Like the basketball version, it is not unusual to feel a bit nauseous. Look at your power files afterwards to see your max and 5 second power for the sprints as well as how well you are able to maintain that power as you fatigue.

Finally, like Dave and Kurt, Bob should also try to do a weekly group cross workout to prepare for the specific demands of cross racing. The one thing that Bob needs to be a bit more careful about, however, is not overdoing it. As an older rider it will take him longer to recover from his workouts than Dave or Kurt, and I would bet that if he did a group cross workout Tuesday, endurance ride on Wednesday and cross suicide drills on Thursday, he would still be tired on Saturday when the race rolls around, meaning that he would not be performing at 100%. Remember that training is a balance of stress and recovery. Doing more training than you can recover from will only lead to fatigue, illness, injury and burnout. It can be useful to examine your Training Stress Balance, or TSB (for definition, see my blog posted on 11/2). If the race is a A or B priority, the TSB should be positive going into the weekend.

For race strategy, the most important thing for Bob is to be realistic. He should look at the riders that are placing just in front of him in early season races and try to stay with them. If Bob has no realistic chance of placing in the top 10, it won't help him to kill himself to try to get to the front of the pack at the start. His best bet is to find riders that are just a little bit better than he is, try to stay with them and hopefully beat them. As he starts to do this, his goals may become more ambitious and when he starts to consistently finish in the top 5 it is probably time to upgrade.

Good luck to all those racing at National Championships this weekend and a happy winter to everyone else! I hope you have enjoyed this series of articles and I encourage you to send me any comments or questions that you may have. Thanks for reading!

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