We investigated the acute and long-term effects of low-intensity resistance exercise (knee extension) with slow movement and tonic force generation on muscular size and strength. This type of exercise was expected to enhance the intramuscular hypoxic environment that might be a factor for muscular hypertrophy. Twenty-four healthy young men without experience of regular exercise training were assigned into three groups (n = 8 for each) and performed the following resistance exercise regimens: low-intensity [~50% of one-repetition maximum (1RM)] with slow movement and tonic force generation (3 s for eccentric and concentric actions, 1-s pause, and no relaxing phase; LST); high-intensity (~80% 1RM) with normal speed (1 s for concentric and eccentric actions, 1 s for relaxing; HN); low-intensity with normal speed (same intensity as for LST and same speed as for HN; LN). In LST and HN, the mean repetition maximum was 8RM. In LN, both intensity and amount of work were matched with those for LST. Each exercise session consisting of three sets was performed three times a week for 12 wk. In LST and HN, exercise training caused significant (P < 0.05) increases in cross-sectional area determined with MRI and isometric strength (maximal voluntary contraction) of the knee extensors, whereas no significant changes were seen in LN. Electromyographic and near-infrared spectroscopic analyses showed that one bout of LST causes sustained muscular activity and the largest muscle deoxygenation among the three types of exercise. The results suggest that intramuscular oxygen environment is important for exercise-induced muscular hypertrophy.
j espere 50 Ã la fin de l annee scolaire.parce que la ca fait pas longtemps que les hormones le travaillent
Michaël C. a écrit:il faudrait voir si 4*5 > 3*5 + 1*15 par exemple
Michaël C. a écrit:
J'aimerai bien connaître l'explication scientifique du couple force-endurance, si elle existe
Body a écrit:Ne tenez pas compte du texte de Vincent juste au dessus du message de Fred, presque tout est faux.
Muscle fibers contract on the 'All or None' principle. In simple terms,
what this means, is that when the nervous system sends a signal to
contract, IF that signal is strong enough, an 'action potential' is
reached. It's like a switch, all fibers in that MU are now on for that
quick point in time. The fibers then contract as hard as they are capable
of for that short point in time. They cannot contract with 50% or 80%,
but only with as much force as they are capable of. The force they exhert
is equal to the tension they experience. This is the part that throws
many people. Don't gloss over this. Think about it. If you are capable of
supporting 200 pounds, then the tension you feel is also 200 pounds.
As a muscle repeatedly contracts, fatigue sets in. Both to the nervous
system and to the fiber itself (mechanical and metabolic). It can
experience damage, loss of available fuel and a "backing up" of metabolic
waste products. These things will lower the force a fiber is capable of
exhibiting. The fiber is still contracting as hard as possible, even
though the force displayed is lessening.
If a muscle is contracting against a less than maximal weight, for
example, 50% of 1RM. It will call upon the exact amount of fibers
required to lift that weight. This does not mean that all the fibers
called upon are being used in an 'always on' state. The CNS will use a
pool of fibers and cycle between them. Think of a 'tug of war', you might
use 50 of your 100 available people, but all 50 might still take turns
tugging. As those fibers experience fatigue and show less force, more
fibers are called upon to 'help'. Once all fibers are contracting, there
are, obviously, no more to call upon. Force will continue to drop, 'rate
coding' and 'synchonization' are then employed for added force. What this
means, is that the MU's receive the 'contraction' pulses at a faster rate
and are called upon in a more 'coordinated' fashion. This optimizes the
force they are applying.
Mon dernier post avant un bon moment
Vincent a écrit:- super volume (jusqu'à 40 séries par muscles tous les jours ou 2 jours)
- super fréquence (entrainement tous les jours)
- super heavy weights (multiples singles à 90-95% ou entrainement négatif)
- super fatigue (drop setS + échec négatif + prefatigue, etc)
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