By Nikki Reiter
Pacing is our body’s way of preserving energy and it is suggested to occur both consciously and subconsciously from our brain and local muscles. Pacing requires a complex integration of brain and muscle signals that is highly debated as the Central Governor theory (the brain) vs. the Peripheral Fatigue model (read more here) with the purpose of keeping our bodies from harming themselves through excessive exertion.
Regardless of what’s regulating fatigue, we as runners can try to maximize what we do know. While doping has been a way to bypass our given biological limits, nutrition is a safer (and legal) way to improve our capacities for both training and performance. Recent research has provided us with some direct applications to young runners, showing us that nutrition plays an important role for runners of all ages, and also that teenagers cannot get away with eating whatever they like!
Here’s how it went: Nineteen boys aged 13-18 years old, trained in endurance running, ate one of the following diets that manipulated carbohydrates (CHO) for 48 hours prior to performing a 10,000m time-trial:
- Normal-CHO (56% of diet)
- High-CHO (70% of diet)
- Low-CHO (25% of diet)
The 10,000 m run was performed on an outdoor, 400 m track, with runners being instructed to finish ‘as quickly as possible and to pace themselves throughout the trial.’
The result: The high-CHO diet led to a faster final sprint and better overall performance, when compared to the low-CHO diet. This would indicate that by eating a high-CHO diet, more ‘ready-energy’ (glycogen) is available for a final sprint in a 10,000 m race.
Interestingly, pace fluctuations were consistent across all groups, at ~7%. However, of the runners who were on the normal- and low-CHO diets, those who least varied their running pace ran fastest – pace fluctuations are energetically costly.
What this means: A high-CHO diet will allow for a faster pace at the end of a race when tapping into a different energy system for sprinting. Not only is a high-CHO diet beneficial to performance, but a low-CHO diet could be considered harmful. This has implications for runners trying to cut calories through reduced CHO consumption.
A final comment: The results of this study present some good advice for all runners – not all calories are created equally when it comes to performance. For example, with many runners adopting a ‘gluten-free’ diet, a resulting consequence can be a reduction in carbohydrates essential for supporting hard training sessions.
Nikki Reiter is a Biomechanist and certified NCCP Performance Coach in Endurance Running. She offers online gait analysis through Run Right Gait Analysis. Visit her website www.run-right.ca for more information.