For many years, endurance athletes have been warned about the risks of weight training. Among the arguments put forward were that of weight gain, accompanying a possible increase in muscle mass, and that of a possible change in muscle fibres, i. e. that energy-saving fibres (slow fibres) would be transformed into more energy-intensive fibres (fast fibres).
Although new scientific studies tend to prove that there is no risk and even that there would be certain advantages to weight training... (assuming of course that the work is well done and that certain rules are respected!)... many trainers are still convinced of the contrary.
We can understand them. Indeed, how to make two antagonistic efforts cohabit,two incompatible training modes?
Bodybuilding and endurance
To properly situate the problem, a small diversions to physiology is necessary.
The energy balance is a fundamental process for our organism and this balance must be absolutely preserved because any disturbance between intake and expenditure can have serious consequences. Two enzymes (proteins) play a decisive role in integrating information from multiple metabolic and hormonal signals in order to activate the metabolic pathways that produce energy or regulate cell growth.
These two proteins (enzymes) are: AMPKand mTOR.
AMPK, an AMP-activated protein kinase (5'AMP-activated protein kinase or 5' adenosine monophosphate-activated protein kinase),plays a key role in the regulation of energy metabolism.
MTOR, the mammalian/target of rapamycin, is an enzyme of the serine/threonine family, regulating proliferation, growth, cell mobility and survival, protein synthesis and transcription. It is considered the keystone of anabolism.
AMPK is activated at the cellular level during high energy expenditure over long periods of time (endurance). It sets up the metabolic pathways that produce energy and inhibits those that consume it, thus playing a role in regulating energy balance.
On the one hand, by doing bodybuilding, we stimulate the activity ofmTORwhich is responsible for activating the syntheses responsible for muscle development and hypertrophy, on the other hand, with endurance training we inhibit it.
As we mentioned earlier, these are two training methods that are not compatible. We can better understand the reluctance of certain trainers who do not want to take the risk, on the one hand of wasting time and on the other hand of compromising results so dearly acquired.
However, in the light of recent studies, it does seem that it is possible to reconcile the two... but obviously this requires a review of the content and place of strength training sessions if we are to obtain the added value they can bring to endurance training programmes.
