Effects of sprint interval training and body weight reduction on power to weight ratio in experience

Brian Quarton [OLD]

http://www.ncbi.nlm.nih.gov/pubmed/19568031

34 guys, divided into 4 groups: Intervals, Weight Loss, Intervals and Weight Loss, and the Control. The study lasted 10 weeks. They weighed in and did a 30 second all-out sprint before and after the study. The Interval group improved their power and maintained weight. The Weight Loss group improved their power a bit and lost 5Kg. These two groups made identical improvements in their W/Kg, 9%. So how about the guys in the Interval and Weight Loss group? They lost weight too, BUT failed to improve their power. Consequently, their W/Kg improvement did not even attain statistical significance. Thus, combining interval training and dieting for weight loss was same as doing neither. I was surprised by this at first, but remember these are experienced, trained cyclists. What do you all think?

Al Truscott

Remember, these are "experienced, trained" cyclists. How much excess weight do they have to lose. If/when I lost 5 kg (11lbs) I couldn't bike for $h!t

If I lose 1.5-2 kg, much less 5, I start to lose power. When I (involuntarily) went from 146 to 133 lbs, I didn't regain my previous power until, after 2 yrs, I finally gained back to 148. The last 4 lbs made all the difference.

Jay Lakamp

A friend of mine (8X IM'r) found out the same way as Al. She lost the wt and the power went with it too. She gained some of her wt back and the power came back also. Like Sampson's hair. For me I'd have to loose at least ~25-35 kg to find out what that would be like.

tim cronk

Tough to draw any real conclusions on a study with trained cyclists. Like Al said how much weight can they lose? Also, how much more power or speed can they gain?

Brian Quarton [OLD]

The average age of these guys was 38 and they started at 78-80Kg (171-176#). I think it is a cautionary example that should guide goalsetting for the OS. Get stronger, get lighter, but be careful going for both.

jimmy augustine

I would think that the weight loss would have a bigger impact on the run anyway. Unless they were so overweight that they were producing excess drag (my attempt at a joke.)

If I could bike the same split at the same metabolic cost 5lbs lighter I would think that it would be a positive over the course of a race with a longer run.

Brian Quarton [OLD]

@Al and Tim, I think there is some value in knowing your optimal weight. Your preformance is not an accident.
@ Jimmy, Unfortunately this was a cycling only study. So you may be right, or not? We need another study!

Tom Glynn

maybe body fat % is a better indicator. Losing 5 lbs when you are at 3% BF is a big deal. Losing 10 when you are at 15%, not so much.

Al Truscott

Posted By Tom Glynn on 22 Feb 2013 12:22 AM
maybe body fat % is a better indicator. Losing 5 lbs when you are at 3% BF is a big deal. Losing 10 when you are at 15%, not so much.

No doubt. Im lucky enough to fluctuate between 5-7% on the Tanita. Drop below 5%, and I start having trouble doing wkos and races.

mgraffeo

If you're overweight, you should ignore this study and improve your diet.

If you're within range of racing weight, you should pay attention to this study and not try to shed pounds while trying to get faster.

I think most of us (except those with body dysmorphic disorder) can use the mirror to tell which group they're in. (says the guy who has a serious case of BDD...)

trisumai

For right or for wrong, I have been losing weight by attempting to maintain a negative 300 cal diet (about 1800/d + whatever I burn for exercise) but the most important part is that I try to keep it at 1.5g/kg -2 g/kg protein so I don't lose lean body mass. Thus far I've lost 6 lbs (168-162) and gone up in FTP. it sure is hard to lose weight though :-( Unlike Al, I'm a relative fatty @ 11-12% BF ;-)