Originally Posted by lauro .
Hello
Hope my topic fits in the "Power Training" Forum.
I've got a question which might be answered pretty easily. I'm new to training with a power meter and I've already bought the book "Training and racing with a powermeter" (I'm not trough yet) but I haven't found an answer so far.
One advantage of a PM is, that it shows you the work in kJ you produced during the training. This is pretty nice, however, I don't know how to use this information for training. Should I refuel all the energy during an exercise? I don't think so. But how much should I eat/drink in comparison to the wasted energy. Is there a rule, tip? Something like: try refueling half of the energy during cycling, half of it at home. I think it depends on the exercises you're doing, too (lets say Endurance 2 rides vs. Level 4 intervals). Right?
I Appreciate everything whether its a link or an answer.
thanks and greets
A lot tied up in your questions, but here's a few thoughts:
- Your PM reports kilojoules of energy burned by turning the cranks. That's not exactly the same as dietary calories burned but for all practical purposes it's close enough so most folks use kj as a direct equivalent to calories burned which is a good starting point.
- How much you refuel on the bike has more to do with the amount folks can tolerate before overloading their systems and running into cramping, bloating and other GI distress. For most riders riding fairly hard that means limiting yourself to something in the range of 250 to 300 Calories per hour while riding at the most and that should include solid foods and any energy drinks.
- For many folks riding hard means burning 500-1100 or more Calories per hour which translates to average power in the 140 to 300 watt range. So unless you're riding really easily you simply can't digest enough calories per hour to keep up with your burn rate so it's almost always a deficit spending game where you're relying heavily on stored fuels including stored glycogen and body fat stores and hopefully to a lesser extent stored muscle protein.
- Typical adult cyclists can store something on the order of 1220-1800 Calories worth of muscle glycogen and blood glucose in their muscles and their liver if they're fully topped up before a ride. That depends a lot on muscle mass as well as training history as one benefit of endurance training is higher muscle glycogen storage.
- Unless you're riding right up at your FTP or VO2 Max pace you're burning some percentage of stored fat as well as sugars in the form of glycogen, glucose, blood lactate, etc. So not all your caloric burn is supported by sugars and the lower the ride intensity relative to your FTP the higher the percentage of fat vs. sugars you'll burn which is among the big benefits of raising FTP as well as race day pacing to preserve precious muscle glycogen which cannot be replenished fully during the ride itself.
- Post ride refueling is essential to replenish your spent glycogen stores especially if you want to train or race again within the next couple of days. You can't consume glycogen directly, you consume carbs and they're converted to glycogen and stored in the muscles. Your body is most efficient at synthesizing and storing muscle glycogen in the first half hour to hour after finishing your rides. This period often called the 'critical half hour' is the best time to get some carbs along with some protein on board as it's used very effectively during that time. Wait an hour or more and your glycogen resynthesis rates drop by half or more and it takes longer to replenish your glycogen stores which can have a big impact on subsequent training sessions or racing on following days.
- There's a lot of studies pointing to the benefits of mixing high GI carbs with some protein for that critical half hour refueling. Lot's of companies tout the best mix (e.g. 3:1, 4:1. 5:1 carb to protein, etc.) but the research is inconclusive and all that's clear is that some protein along with the carbs is beneficial. Low fat chocolate milk is a favorite of many riders and supported by a few studies but there are good commercial recovery drinks like Endurox, Recoverite, Metabolol, etc. Or a fruit smoothy with some lowfat yogurt added or with added protein powder or a handful of other concoctions can get the job done.
- There's still a limit to how much you can store as glycogen during the post ride period and most commercial drinks advocate up to 300-400 Calories or so in that first period followed an hour later by another dose or a regular meal. You can certainly eat more but the excess will be stored as fat. Not necessarily a problem if you're trying to maintain or even gain weight but not great if you're trying to lose weight.
- In the end weight maintenance is a matter of balancing calories ingested vs. burned including resting metabolic burn rates along with whatever you burned turning the pedals or with other exercise. So over the course of a day, the week or longer time frames the calories should balance to maintain your same weight. So if you're trying to hold an even weight you do want to replenish what you burned in exercise and during the rest of the day and night but you want to do that in a way that includes all on bike food, pre ride, post ride and regular meals, snacks, etc. So think big picture for weight management but realize that there are limits to on-bike intake and best times tor refuel as well as limits (if you want most of it stored as glycogen and not fat) for post ride refueling.
-Dave
