When pedaling at a slow pace, for example when cruising at 26-30 km/h on a flat course (corresponding to a Lento Intensity in 53x12.com programs), the tendency is to utilize a mixture of roughly 50% sugars and 50% fats as fuel for the activity. 

By speeding up a little, the percentage of utilized fats decreases and further drops down as we progressively increase the intensity, reaching minimal levels at anaerobic threshold. 

In fact, laboratory research widely documented that for efforts involving lactic acid concentrations close to 4 mM/L, the energetic source is 100% carbohydrates. The same happens for intensities higher than anaerobic threshold values. 

The lipid power is the absolute quantity of fats that muscles utilize as fuel for activity expressed in g/min. 

If, instead of the percentage of utilized fats, we consider the absolute quantity of fats consumed per minute (the lipid power), we find that the higher value corresponds to intensities equal to 80-90% of the anaerobic threshold (within the range of Medio pace). 
Such intensities generally correspond to lactic acid concentrations close to 2 mM/L.

 

Every cyclist should have the interest in improving his own lipid power: increasing fats consumption at medium intensities allows the rider to spare precious glycogen stores, saving them for the highest efforts or the final part of the race. 
The maximum lipid power in well-trained athletes can reach values of 0.7-0.8 g/min, equal to 380-400 Kcal/hour. 

Medium intensities are therefore crucial for a cyclist’s training, especially when focused on long endurance sessions, being the most effective in improving the muscular capacity to utilize fat amounts per minute. 

Such intensities should be calibrated on the personal capabilities of the athlete, pointing out the great importance in checking lactate values at different intensities of effort through proper testing protocols.