Progressive overload: the ultimate determinant of growth
Irrespective of the above factors, the ultimate key to larger and stronger muscles is
progressive overload. Individuals have achieved growth using from 1 rep to 50 reps with a
number of different protocols, so it is impossible to say unequivocally that there is a ‘best’
program for stimulating growth. As long as stress continues to be applied to the body and
muscles are forced to work against progressively greater loads, assuming adequate recovery and
nutrients are provided, growth should occur in the long run. The above discussion is an attempt
to optimize the nature of the growth stimulus. A summary of the requirements for growth
appear in table 3.
Table 3: Summary of training requirements for growth- Use weights between 60-85% of maximum (roughly 6-20 reps)
- Use a controlled eccentric (lowering) movement.
- Apply proper progressive overload.
- Supply adequate nutrients and allow adequate recovery
- Train a muscle once every 4-7 days.
Section 3: Energy Metabolism during weight training
During muscular contraction above 20% of 1RM, blood flow to the muscle is blocked (90)
and energy production comes solely from anaerobic sources such as the breakdown of ATP-CP
and glycogen depending on the length of the set (see chapter 19 for more details). Weight training
cannot use fat for fuel during a set. However, fat breakdown increases during heavy weight
training (91,92) indicating that fat may be used during recovery between sets to replenish ATP.
Increases in fat breakdown during weight training are most likely stimulated by the hormonal
response to training, especially increases in levels of adrenaline and noradrenaline.
Fatigue during weight training is addressed in section 4 based on energy systems. Sets of
1-5 repetitions, as typically used by powerlifters and lasting 20 seconds or less, are discussed
separately from sets of 20-60 seconds, typically used by bodybuilders. The metabolism of both
energy systems are discussed in the previous chapter and are not be repeated here.
Section 4: Fatigue and weight training
As discussed in chapter 18, the impact of a total lack of carbohydrates on endurance
training is very consistent: performance is maintained or improved at low intensities (below 75%
of maximum heart rate) but decreased at higher intensities (75-85% of maximum heart rate or
approximately the lactate threshold). However, the effects of a ketogenic diet on weight training
are not as well established.