Question on Power & Weight

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.

Comments

[Chris H]

This provides some interesting material to mull over. I spend a lot of time thinking about my weight, which essentially remained unchanged despite a spring and summer of consistent exercise. I rarely dipped below 10 hours/week and regularly hit 14 or so in my triathlon training. I look fitter, ie leaner, recovered faster, and became stronger and faster across the three disciplines. There were times when I'd feel really frustrated over not dropping more weight. Since my season is over I'm looking to spend 4-8 weeks in a prep phase. Small chain ring, gentle runs, etc...I've pretty much given up worrying about the number and simply trusting that if I do the work, I'll improve.

[Clay Dudley]

This is almost exactly my situation. Now I have some excellent things to consider for the next several months.
This also explains why my last century ride was somewhat of a disaster as I'd started my weight loss (low calorie) plan several weeks beforehand.
You would think someone my age would know better!

[Fulton]

Hi Joe,
I have a question for you. My average heart rate at FTP is 167. I am 44 years old, and I have been training seriously for the last 4 years. When i do Vomax and anaerobic intervals, i have a very hard time bringing my heart rate to that level (I use power). However, I can usually max out my heart rate (183 bpm) at the end of a 10 miles TT? What could be the reasons for that?

[Joe Friel]

Fulton-You didn't say but I expect your intervals are shorter than 4 minutes. your heart simply hasn't caught up with the effort/intensity in that short amount of time. That's good. The greater your aerobic fitness the slower the heart responds to high effort.

[Fulton]

Hi Joe,
Thank you for your response!. Yes, they are 3 min for Vomax. Then, if the heart is slow to respond, am I still promoting Vomax adaptations such as higher cardiac stroke volume? thank you!

[Joe Friel]

Fulton--yes you are. But as fitness improves, increases become harder to come by. But the bottom line is that I'd stop being concerned with your HR and pay attention almost entirely to your output. The more refined gains as fitness increases come from changes that take place in the muscles.

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I rarely dipped below 10 hours/week and regularly hit 14 or so in my triathlon training. I look fitter, ie leaner, recovered faster, and became stronger and faster across the three disciplines.

[rumpole]

I read the article you wrote about what an FTP "should" be and have a question. I take it that this is your idea of a median? In other words, your average X year old at 160 pounds, with no injuries etc should be able to reach a wattage of 2*WEIGHT - (.035 * AGE). For a 160lb 34 year old, for example, an FTP of 320 is not genetic freakery. Is that what you meant?

[Joe Friel]

rumpole--320w for a 34 yo, 160lb, male rider is quite reasonable assuming there are no other issues such as altitude or low weekly training stress on the bike (as in common for many triathletes).

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Losing 20 pounds in 3 months is quite a challenge and very dangerous may be.

[John]

As a 65 year old road cyclist, riding for almost 8 years, it's been my goal to increase my power and lose enough weight to achieve 3.5 watts/kg. At 73 kg, which is about my ideal weight and quite lean, that means my FTP would have to be 256 watts; it's currently 240 so I still have some work to do. Why 3.5 watts/kg? Well, according to Coggan's Power Profile chart in “Training and Racing with a Power Meter,” that would put me in the lower range of a Cat 3 cyclist and it's just a goal, a challenge that when I meet it will keep me from getting dropped on group rides and be able to spin, not grind up the climbs here in Colorado. According to your formula for estimating FTP, at 73 kg, or 160.6 lbs, doubling that, subtracting 15% would put me at 3.73 watts/kg, or a bit higher up the Cat 3 ladder if I could reach that. Maybe I've set my goal too low or maybe you're addressing a difference audience than guys like me who work and can train 8 to at most 12 hours/week. So my question is, who is your target audience? Are you saying that we should all be able to achieve Cat 3 or higher performance levels?

[Joe Friel]

John--You'd also want to deduct 5% for altitude assuming 5,000 feet. And at around 8hpw another approx 5% (there was a follow up to that post where altitude is mentioned along with other additional variables). I was assuming sea level and at least 2hpd. There would be other variables that are even more difficult to throw in such as diet, lifestyle stress, etc. But realize that this is all just my way of predicting across a very broad range of athletes. It doesnt mean everyone will hit that number. Some higher and some lower. It's just a ballpark to give one an idea of the general power to be expected. If anything I've found it a bit high for older athletes. I'm sure the drop in power is not straight line as we age. So I wouldn't take it as what _you_ are expected to do. But it may help to give focus to your goal.