No Pain No Gain or Train Low, Perform High
It has long being believed that providing key nutrients for maximal physiological performance was the best possible nutritional approach to support endurance training. A good example is the isotonic carbohydrate fluid replacement that was thought to keep top athletes going 33% longer. For exercise periods over 60 minutes long, administration has led to postponing the onset of fatigue and improving endurance performance. Carbohydrates provided a much needed fuel substrate, sparing muscle and liver glycogen and thus preventing hypoglycaemia. But, an interesting idea has emerged from the world of sports science lately, the ‘train low, compete high’ theory (though not without controversy). This concept suggests that training in a low carbohydrate (low glycogen) state will enable a greater training adaptation, ensuring a better performance when it comes to competition.
Let us have a look at exercise on a grassroots level. The main purpose of training simply is to create a stress, causing us to adapt. In endurance exercise this happens mainly through activation of pathways to enhance mitochondrial biogenesis (mitochondria are the energy producing source of cells), fiber type switching (building-up of slow fibers, which are muscle fibers more suitable for endurance sport), and boosting the use of fats for energy (fat burning). Such changes will enable an athlete to perform harder and longer. Therefore, it is obviously desirable to try to maximize these beneficial signalling effects.
It appears that the activation of these signalling substances depends on nutrient status, with signalling enhanced in a low carbohydrate environment. Signalling is activated in environments of increased stress and glucose availability and glycogen (the storage form of glucose in our muscles) will act as a buffer to relieve the stress our bodies feel.
So while there may be only few things more capable of giving us that great moment of ease, than downing a nice cold energy drink during a tough training session, it seems it actually may be a case of ’no pain, no gain’. The stress relief on our muscles we get from the carbohydrate drink may suppress our ability to adapt and, therefore, our long term performance ability.
This is a rather new concept in sports science and as such the evidence is only starting to gather. But there is enough to make you think. When people train twice daily (the first session creates a low glycogen status for the second training session), the activity of muscle mitochondria is higher than in those who train only once daily (while both groups train the same amount per week, 2×2 or 1×4).
Ingesting an energy drink after the training session causes marked reduction in adaption signalling activity. In one study, two groups performed high intensity interval training twice daily, whereas one group was loaded with carbohydrates in between sessions. In the carbs depleted group measures of muscle adaptation were significantly higher.
This Training Strategy Is not Suitable for Everyone
Performing in a low carbohydrate environment will worsen performance. An athlete will not, at least initially, be able to sustain their usual intensity of training and if their progress is measured in seconds, they may find the change quite discouraging. Athletes should be aware that this is a preparation stage. For competition (where the aim is performance and not adaptation), the athletes ought to maintain high glycogen stores and glucose/fructose intake to maximize their performance. In order to create a low carbohydrate environment, carbohydrate intake should be restricted throughout the whole day and not just around training periods. Post training a practical advice is not to consume food for at least one hour in order to ensure maximal adaptations. A low carbohydrate intake, however, is associated with weakening of the immune system and ca 100g/day of carbohydrate should be consumed by the active athlete in order to prevent this risk. It is, therefore, necessary to limit such programmes to ca 6 weeks in order to limit infection and prevent over-training. This training concept appears to be ill-advised for the resistance training athletes, where fuel repletion is essential for anabolism. Increases in these types of endurance adaptation pathways would inhibit those badly needed for protein synthesis.