Strategically limiting carbohydrates
The authors of the “fuel for the work required” approach propose that the positive effects of training low are dependent on commencing training with muscle glycogen levels within a specific range. Glycogen levels are affected by carbohydrate (CHO) intake and exercise, so athletes have to strategically limit their carbohydrate availability.
“We define CHO availability as the sum of the endogenous (i.e., muscle and liver glycogen) and exogenous CHO (i.e. CHO consumed before and/or during exercise) that is available to sustain the required training intensity and duration.”
Planning meals around training sessions
As we know from the previous article, constantly training in a state of low-carbohydrate availability can result in the loss of high-intensity performance and ability to maintain training load and a higher risk of illness. Fuelling for the work required allows athletes to avoid these issues while gaining the benefits of training low.
In practice, this means that athletes choose high-carb foods before and during high-intensity sessions. They will eat low-carb meals before recovery sessions and consume nothing on the ride. Then in the evening of recovery days, they will begin consuming carbohydrate again in preparation for another intense session coming the following day.
Just like it’s crucial to include both low- and high-intensity training sessions, it’s also beneficial to train under low- and high-carbohydrate availability. The authors describe three “train low” strategies that will allow you to train with lower muscle glycogen stores.
Training twice per day with minimal refuelling
In this approach, subjects complete a morning training session to reduce muscle glycogen followed by several hours of reduced CHO intake so that the second training session of the day is commenced with reduced muscle glycogen. Depending on the length of the interval between the first and second session (i.e. recover low) and the actual duration of the second training session (i.e. train low), the accumulated low-glycogen period could range from 3 to 8 h.
Exercising fasted represents a simpler model of “train low” whereby breakfast is consumed after a morning training session. In this model, pre-exercise muscle glycogen is not different between fasted or fed conditions, but liver glycogen and circulating glucose is higher during fed conditions.
Sleeping low and training low
In the “sleep-low, train-low” model, participants perform an evening training session, restrict CHO during overnight recovery, and then complete a fasted training session the following morning. The accumulative total time with reduced muscle glycogen could, therefore, extend to 12–14 h, depending on the timing and duration of the training sessions and sleep periods.
Now that we understand the concept of fuelling for the work required and the necessary train-low strategies, let’s look at a practical application. The following article will describe 4 days of training and fuelling for a trained cyclist.