Your inroad and strength return is determined by the time course for re-synthesis of ATP/PcR
Also, occlusion and ACIT prevent re-synthesis during exercise, this is why there is such a huge quick strength loss.
The time course of phosphorylcreatine resynthesis during recovery of the quadriceps muscle in man
R. C. Harris1, R. H. T. Edwards2, E. Hultman3 , L. O. Nordesjö4, B. Nylind5 and K. Sahlin1
Summary The time course of phosphorylcreatine (PC) resynthesis in the human m. quadriceps femoris was studied during recovery from exhaustive dynamic exercise and from isometric contraction sustained to fatigue. The immediate postexercise muscle PC content after either form of exercise was 15 to 16% of the resting muscle content. The time course of PC resynthesis during recovery was biphasic exhibiting a fast and a slow recovery component. The half-time for the fast component was 21 to 22 s but this accounted for a smaller fraction of the total PC restored during recovery from the isometric contraction than after the dynamic exercise. The half-time for the slow component was in each case more than 170 s. After 2 and 4 min recovery the total amounts of PC resynthesized after the isometric exercise were significantly lower than from the dynamic exercise.
Occlusion of the circulation to the quadriceps completely abolished the resynthesis of PC. Restoration of resynthesis occurred only after release of occlusion.
In addition to support of the above, this next one also shows that really low reps and really high reps do NOT delpete ATP very much.
Energy supply and muscle fatigue in humans
K. SAHLIN, M. TONKONOGI & K. SÖDERLUND
Limitations in energy supply is a classical hypothesis of muscle fatigue. The present paper reviews the evidence available from human studies that energy deficiency is an important factor in fatigue. The maximal rate of energy expenditure determined in skinned fibres is close to the rate of adenosine triphosphate (ATP) utilisation observed in vivo and data suggest that performance during short bursts of exercise (<5 s duration) primarily is limited by other factors than energy supply (e.g. Vmax of myosine adenosine triphosphatase (ATPase), motor unit recruitment, engaged muscle mass). Within 10 s of exercise maximal power output decreases considerably and coincides with depletion of phosphocreatine. During recovery, maximal force and power output is restored with a similar time course as the resynthesis of phosphocreatine. Increases in muscle store of phosphocreatine through dietary supplementation with creatine increases performance during high-intensity exercise. These findings support the hypothesis that energy supply limits performance during high-intensity exercise. It is well documented that pre-exercise muscle glycogen content is related to performance during moderate intensity exercise. Recent data indicates that the interfibre variation in phosphocreatine is large after prolonged exercise to fatigue and that some fibres are depleted to the same extent as after high-intensity exercise. (during prolonged exercise...) Despite relatively small decreases in ATP, the products of ATP hydrolysis (Pi and free ADP) may increase considerably. FreeADP calculated from the creatine kinase reaction increases 10-fold both after high-intensity exercise and after prolonged exercise to fatigue. It is suggested that local increases in ADP may reach inhibitory levels for the contraction process.
In addition to more support for ATP/PcR inducing the strength loss (inroad), this next one also shows that type II fibers are easier to deplete of energy reserves (ATP/PCr)
Metabolic response of type I and II muscle fibers during repeated bouts of maximal exercise in humans
A. Casey, D. Constantin-Teodosiu, S. Howell, E. Hultman and P. L. Greenhaff
Department of Physiology and Pharmacology, University of Nottingham Medical School, Queen's Medical Center, United Kingdom.
Nine male subjects performed two bouts of 30-s maximal isokinetic cycling. Each bout of exercise was performed at 80 revolutions/min and was separated by 4 min of recovery. Mixed-muscle phosphocreatine (PCr) resynthesis during recovery (88.1 +/- 6.1%) was positively correlated with the restoration of total work production during bout 2 (r = 0.80, P < 0.05). During bout 1, ATP and PCr utilization were greater in type II compared with type I fibers (P < 0.01 and P < 0.05, respectively). The subsequent 4-min period of recovery was insufficient to allow total restoration of ATP and PCr in type II fibers, but restoration of ATP and PCr in type I fibers was almost complete. During the second bout of exercise, ATP and PCr utilization were reduced in type II fibers (P < 0.01), without a corresponding change in type I fibers, and performance was also significantly reduced. The reduction in work capacity observed during bout 2 may have been related to a slower resynthesis, and consequently a reduced availability, of ATP and PCr in type II fibers.
Ce qui vient également confirmer l'idée de la déplétion momentannée d'énergie comme stimulus et donc le fait qu'il est inutile de faire plus d'une série [puisqu'en faire plus n'augmente pas la déplétion MOMENTANNEE d'énergie !]
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J'en profite aussi pour glisser un complément sur la fréquence d'entrainement (2 liens):
Study 0 : 1x = 62% de 3x
Study 1 : 1x et 2x = 73% de 3x
Study 2 : 2x = 90% de 3x
Study 3 : 1x et 2x = 73% de 3x
Study 4 : 1x = 2x
entrainer un muscle 1x par semaine permet d'obtenir environ 70% des gains obtenus avec 3 entrainement par semaine (et 2x environ 80%) [au dela de 3x par semaine pour un meme muscle, les gains n'augmentent plus ou à peine] C'est-à -dire qu'en moyenne s'entrainer 3x par semaine apporte 40% plus de gains, on progresserait 1.4x plus vite ! Sur un an quelqu'un qui a fait 1 série 1x par semaine et qui aurait gagné 10kg aurait pu en gagner 14 avec 3 entrainements par semaine...
Ca peut être bien aussi de faire varier la fréquence selon la fatigue nerveuse ou articulaire... Enfin, il faut ajouter qu'une grosse fréquence d'entrainement peut également engendrer des gains nerveux (facilitation synaptique) donc musculairement, avec 3 entrainements on gagne probablement moins de 40% de plus par rapport à 1x par semaine.
