Today I received a note from an athlete wanting me to predict his future fitness relative to power. I’ll get out my crystal ball and take a look. Here’s his question…
Q: My power avg. jumped from 190 to 216 and my resting heart rate has dropped to 152. I'm 66 yrs. young and trying to improve. My current weight is 175-180. Assuming a weight loss of 20lbs and continued "smart" training. What can I expect the power avg. to be in 3 mos? Thanks a bunch. -Bill
A: I’ve got to do a lot of guessing here. First, I’m assuming he means that his “power average” is functional threshold power (FTP—the power he can maintain for 60 minutes at race effort). A 26-watt increase from 190 to 216, about 14%, is very good. He’s been doing something right in training.
Second, I’m not sure what he means by his resting heart rate has dropped to 152. That’s obviously much too high for RHR. So either it was a typo and he meant “52,” or else he means his lactate threshold heart rate has become 152. But since his question doesn’t involve heart rate I won’t worry about it.
Losing 20 pounds in 3 months is quite a challenge. That’s about a pound and a half per week, or about a 750-calorie-per-day deficit. For a couple of weeks that can be managed. But for 12 weeks this will be very challenging to maintain, especially after the easily lost excess fat comes off in the early stages. The impact of such an aggressive weight-loss program will mean decreased energy for training and slow recovery as the 12 weeks progresses. There are lots of related issues here, such as his current percent body fat and the probability of muscle loss, which I won’t get into, but these are also related to training. The bottom line is that performance is likely not to improve until bodyweight stabilizes. Power may even decline during this time. Then it may be another 6 weeks or so until real progress is seen in power performance.
What can he expect to see happen to his FTP once normally manageable training resumes? I wrote a blog on this about a year ago—how to predict your FTP. The bottom line of that post is that he can get a rough estimate of what it may become by doubling his body weight in pounds and subtracting a half percent for every year over age 35. Based on this and assuming his weight in 3 months will be 160 pounds then his FTP could be around 270 watts (160 x 2 = 320, 320 x 15.5% ≈ 50, 320 – 50 = 270). That doesn’t mean he would all of a sudden be capable of riding at 270w for an hour just because he lost weight (more on weight relative to power shortly). He’s got to train to become more aerobically fit, also.
To become more aerobically fit and thus raise his FTP, which is a good predictor of endurance cycling performance, he would need to do 3 things:
*Increase aerobic capacity (VO2 max). This is done as described in my blog here.
*Raise lactate threshold as a percent of VO2 max. And, again, rather than go into the details here, please read my blog post on this.
*Become more economical in pedaling and handling a bicycle. This may be the most important of the 3. You can read the details here.
All of this training could take an additional 6 months to a year, or perhaps even more, in order to realize a FTP of 270w. That would be an increase of 25% over where he is now—a huge amount. While that is possible, at least on paper, it really comes down to his genetic makeup and how “smart” (as he put it) that he trains. He may never see a 270w FTP, but I have no doubt that his power performance will improve if he trains with adequate volume and intensity as described in the above blog posts, and increases both of these at a rate his body can healthfully sustain.
I should also point out that it’s not the weight loss that will potentially produce such a number, but rather a sound training program. He could start training for a FTP of 270w right now without losing a single pound. The only time body weight will ever be significantly apparent on his bike is when climbing a hill. He will climb faster than at his current body weight for any given power output. His FTP will not rise, however, just because he lost weight.