What determines endurance?
Endurance in the sense of being able to complete or compete in long distance races is determined by the percentage of energy supplied from fat metabolism versus glycogen. Glycogen is the vital fuel source for high intensity efforts and when it's gone your race is over. The percentage of energy supplied by fat versus glycogen depends on the intensity (the percentage of threshold power) you are riding at. Well below threshold and fat provides a high percentage of energy, whereas well above threshold and glycogen becomes the major fuel source.
Whilst the 'fat-burning zone' has been used as a sales gimmick, it really is no more than an intensity level low enough to allow the slow rate of fat metabolism to supply energy demands for exercise. Exercise harder and you burn MORE calories as well as fat, but, the percentage of energy supply from glycogen increases. Your anaerobic system metabolises glycogen, producing lactate and other by-products. Aerobic metabolism of fat produces no lactate.
If a rider can increase their threshold power, then the intensity and speed at which they can now ride at whilst still relying on fat stores will be higher. This translates to more speed and endurance. At 7000kCal of energy per kg, fat is a HUGE energy pool, even for riders with a very low body fat percentage.
As highlighted in previous newsletters, muscle and liver glycogen stores are limited and will deplete during a ride. Nutrition can only slow the rate of depletion but increasing stores during a ride is not possible. The biggest factor affecting the rate of depletion is the intensity, as a percentage of your threshold power, that you ride at. Because of this, it's quite easy to be spent in just 2 hours and face a long crawl home!
Sweet spot / aerobic endurance training is very effective at raising threshold power, and hence, the rider is able to utilise fat as a fuel source at a higher power output. What's more, this increase in threshold power and endurance is achieved on low volume training rather than 5 hour LSD rides. For the working, non-professional rider, this is pretty good news.
The above information is designed to explain what happens metabolically as intensity changes and how this affects your endurance. This allows you to be conscious of what the cost of high intensity efforts are, as well as to plan your nutrition to reduce your rate of glycogen depletion when the pace is high.
Nutrition provides a key component, so if you would like more insight into nutrition for racing, training and recovery, then book your spot for our event evening next week - READ RIGHT HAND COLUMN. |
Event Evening at Cadence:
NUTRITION FOR OPTIMAL TRAINING, RACING AND RECOVERY...
Cadence is hosting an evening in conjunction with Retha Shaw (dietician) and the DHS High Performance Centre in Morningside. This is a great opportunity for you to learn from a dietician, a biokineticist and a chiropractor on how to improve your performance!
Topics and services will be:
- Carboloading.
- Fluid intake during endurance events.
- Maximising muscle recovery between races and training sessions.
- The value of stretching by Wayne Minnie (Biokineticist).
- Free spinal screening from a chiropractor.
Goodie Bags & Lucky Draw:
Peptopro and Futurelife will have give aways to all attendees and there will be a lucky draw prize from Peptopro.
Catering:
Snacks and drinks
will be provided and we would be most grateful if you can RSVP so we can know numbers. You don't need to have trained with us at Cadence to come along, you just need to RSVP here: RSVP
The venue is Cadence Durban North, 6pm on Thursday 8th September.
All are welcome, even if you just want to come along to see and ask what Cadence is all about. |
