54 | Cycling World
Training and Nutrition
High-Energy
Nutrition
By Health & Fitness expert James Crossley,
who is working on his ‘Fit at Forty’ Campaign.
For more information, check out
@MrJamesCrossley on Twitter or Instagram
or visit www.MrJamesCrossley.com.
E
nergy production during a long-distance bike ride
is fuelled primarily from carbohydrate and fat.
Carbohydrates are the best fuel for the body and
are stored in the muscles and liver as glycogen.
Inadequate fuelling both before and during rides will not
only result in a less-than-optimal performance but may
also lead to hitting “The Wall”.
A basic knowledge of energy systems is useful to
understand what is going on during different efforts on a
ride. We have three energy systems that are called upon
during s rints, intense efforts and steady- aced riding.
2. Anaerobic or Lactic System
The Anaerobic system utilises and breaks down
carbohydrate (glycolysis) providing energy from anywhere
between ten seconds to three minutes without the use
of oxygen (anaerobic). Lactic acid is a bi-product of
anaerobic glycolysis.
If exercise intensity remains high and oxygen can’t
be used to provide fuel (aerobic glycolysis), lactic acid
separates into lactate and hydrogen ions (H+), the latter
causing blood acidosis which is responsible for the
burning sensation during, and feelings of nausea after,
intense efforts.
Example: A 60-second power test
1. Phosphocreatine System –
The Sprint System
This system provides energy for a maximum of 10-12
seconds. ATP is stored in all cells, and in particular the
muscles. The Alactic system doesn’t require a blood
supply for energy production, instead relying on the
availability of creatine phosphate (CP). Due to its limited
supply, this system is depleted quickly and, following total
depletion, can require up to eight minutes of rest before
being resynthesized.
Example: Initial kick during a breakaway attack
3. The Aerobic system
The aerobic system uses oxygen to fuel the breakdown
of carbohydrates and fats and is the dominant energy
system during longer rides.
After about 90-minutes, our carbohydrate reserves begin
to run low and we must refuel to continue cycling. The
rate of carbohydrate usage will depend on the intensity
of the work being performed, for example, riding at 100w
for one hour will burn 360 kJ/calories, while riding at
200w = 720kJ/ calories.
Example: A four-hour ride