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An appropriate topic, especially for those aiming for Golovane this weekend, Sani2C, JoBerg2C, Pondo Pedal, etc... Below is a chart showing your body's fuel useage during moderate intensity continuous exercise. What's interesting to note from the chart is that your muscles only provide 50% of your total fuel (glycogen) when completely carb-loaded, your blood glucose 10% and fat reserve 40%. As exercise continues you can see that muscle glycogen levels drop. At the 2 hr. mark, your muscles are only providing approx. 30% of your body's total fuel usage. However, your blood glucose levels actually take up the slack and provide more (around 15%) fuel for exercise than it did at the start.
After the 2 hr. mark you can see that if you don't consume any carbs during exercise (i.e. gels, energy drink, food, etc.) that your blood glucose levels drop sharply. At the 3 hr. mark, your blood glucose levels will start to dip below 10% of your total body's useage. By the 4 hr. mark, your blood glucose levels will have tanked (in addition to your muscle glycogen reserve). This is the point where you "bonk".
Now, if instead at the 2 hr. mark you ingest some carbs (liquids act quicker), you will stave-off the dreaded "bonk". However, you can clearly see that regardless of how much carbs you ingest, you CANNOT restore muscle glycogen levels to their full/orginal state. That's because your body can't process the intake of carbs quickly enough and your muscles need a rest (so to speak) to clear out the high acidity and repair themselves before glycogen resynthesis.
The most important takeaway from this chart/graph is to ensure that BEFORE you start your long endurance training (or racing) that your Carb levels are topped-off. You want your muscle glycogen levels maxed out as well as your blood glucose levels. Plus, anything you can do to spare muscle glycogen levels the better, such as ensuring you consume Carbs during endurance exercise.
Note: Glycogen depletion will happen MUCH faster if the intensity level is increased. Instead of muscle glycogen being depleted at the 4 hr. mark (shown above) it could happen at the 2-3 hr. mark..
Mark Carroll
Level 2 Cycling Coach |
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We encourage higher leg speed for power as well as endurance at Cadence Cycling. What is Chris Carmichael's view?
"Power is best developed at high cadence - 100 to 130rpm for most riders.
"Because power is defined as work over time, riding up a hill in a big gear at 50rpm doesn't develop power, it develops strength.
"You need to develop strength with low cadence work, then add power by doing intervals at a high cadence."
The 2 highest power outputs we have seen at Cadence Cycling during a 20 minute threshold test is 376Watts and 381Watts. These figures were from 2 different riders but both efforts were completed at an average cadence of over 100rpm.
What can you do?
For strength, low cadence drills aren't popular, but we have grown to love them because of the results we see. Either doing them as individual leg drills or with both legs and anywhere from 2min to 6min at varying power output intensities to make sure you get the most out the duration of the interval.
For speed and power, those on the current training block at Cadence will have noticed a big emphasis on leg speed introduced as part of the warm up. It's a tremendously valuable use of warm up time that serves to help increase speed as well as warm up the nervous and muscular systems. It also improves neuro-muscular communication which riders gradually begin to notice with less bouncing, a more fluid pedal stroke and with reduced tendency to rock around and fight the bike.
Combining the above in a training cycle with high power, high cadence drills brings it all together to improve performance, not only for short and hard efforts, but also for endurance and greater speed, even over marathon MTB distances.
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