The body uses two main macronutrients to derive energy to fuel an activity, namely carbohydrates and fats. The former being the preferred source of quick energy, and the latter for sustained energy provided that the body can process fats for fuel. It is easier to run out of carbohydrates, which are stored in the muscles in the form of glycogen. Glycogen is a localized energy store that can only be used by the muscles in which it is locked. When these glycogen stores are depleted muscles get fatigued, this is referred to as ‘bonking’. A way to minimize glycogen depletion, and therefore fatigue, could be to consume adequate carbohydrates, before and during a ride.
A quote that has gained popularity with the boom of cyclists across the world - ‘Burn Fat not Fuel’ places an emphasis on cycling being beneficial to our bodies and our environment too. Since one uses their entire body when they cycle riding too far or too fast results in fatigue, thus making cyclists prone to muscle fatigue. Fatigue is caused by a wide range of physiological reactions. Muscle fatigue can be a result of overuse, insufficient rest, inadequate recovery and possibly inadequate nutrition or hydration. Read on for what causes muscle fatigue and how to deal with it.
INADEQUATE FUEL
BUILDUP OF LACTIC ACID
Being an aerobic activity, cycling requires that carbohydrates and fats are broken down to form an energy yielding substance called adenosine triphosphate. This substance powers muscular contractions. Riding at a fast pace can make the body unable to take in sufficient oxygen for this process to occur efficiently. Thus resulting in the incomplete breaking down of carbohydrates in an oxygen-free environment. The byproduct of this is called lactic acid, which can cause the burning/tired sensation felt when you try to pedal. Large amounts of lactic acid can make you slow down or even need to stop cycling. Getting back on the saddle will be possible only once you have rested and the built up lactic acid levels have reduced.
SPECIFIC MUSCLE FATIGUE
Cycling is an activity that engages the whole body, but typically uses a few muscles constantly to drive motion, specifically the quadriceps, hamstrings and gluteus maximus muscles. If you are a beginner, you could find that your legs tire out after a short time on the saddle. However, with regular cycling you will experience an increase in local muscular endurance. This increased muscular endurance is the result of an increase in the energy producing cells called mitochondria, and an increase in the size, and number of aerobic muscle fibers. The greater your local muscular endurance is, the more resistant your muscles will be to fatigue. Hence, your muscles can work for longer before tiring.
INADEQUATE CARDIOVASCULAR FITNESS
The cardiovascular system consists of the heart, lungs, blood and blood vessels, and is responsible for taking in, transporting and utilizing oxygen. Inadequate cardiovascular fitness would mean that one’s muscles do not receive the essential oxygen required for prolonged activity, and this could result in early fatigue or even exhaustion. Factors like heart and lung capacity, red blood cell count and capillary density can affect one’s cycling performance and a strong cardiovascular system means less fatigue experienced. Regular exercise and training can help boost cardiovascular fitness, and therefore resistance to fatigue.
OTHER FACTORS
Fatigued leg muscles, particularly after a less tiring day on the saddle, could be a sign of a circulation problem known as peripheral artery disease. PAD means that the blood vessels away from the heart have narrowed due to plaque build-up and hence could make your legs tired or sore with a small bit of activity.
Conclusion
Fatigue and our body's ability to maintain prolonged effort is built on an intricately balanced system. One or more of these systems becoming weaker can cause the whole system to collapse. Fatigue at the end of a long ride is normal, but can be reduced by making sure to drink enough water before, during and after a ride, and by making sure to get enough potassium to help the muscles recover from the strain of cycling. Bananas, potatoes and sweet potatoes, orange juice and tomatoes are all good, natural sources of potassium. Finally, stretching your body and your muscles before and after your ride can help with preparation for a ride, and recovery from a ride thereby preventing early fatigue.
