Protein Synthesis/Metabolism after Workout

[syxxnutz]

As far as I understand, protein synthesis increases for approximately 48 hours after a workout. What if a person was not able to improve strength or endurance during a workout? If strength did not improve from last workout(perhaps 1 or 2 fewer reps completed), is there the same metabolic effect? Is there a percentage decrease based on this? Is there some lower limit of fatigue that must be reached before this effect is created?

I move books all day, but I just assume there is no metabolic effect from this because it is much lower weight, even though it is tiring. Is the same true for even a slight drop in weight?

Sorry about the wordiness of the post, but I'm having a hard time explaining exactly what I mean.

[dinabol]

MIXED MUSCLE PROTEIN SYNTHESIS AND BREAKDOWN AFTER RESISTANCE EXERCISE IN HUMANS


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Phillips et al (1) examined mixed muscle protein fractional synthesis rate and fractional breakdown rate after either concentric or eccentric resistance training. The training consisted of 8 sets of 8 of either concentric or eccentric repetitions at 80% 1 RM. FSR and FBR were determined in the 8 untrained subjects using primed constant infusions of [2H5]phenylalanine and 15N-phenlyalanine, respectively. Protein synthesis/breakdown was examined at rest and at 3, 24, and 48 hours postexercise.

FINDINGS: There were no significant differences between the concentric and eccentric groups for protein synthesis, protein breakdown, or net protein synthesis. Protein synthesis was significantly elevated at all measurement points (112% at 3 hours, 65% at 24 hours, and 34% at 48 hours). Protein breakdown was significantly elevated at 3 hours (31%) and 24 hours (18%) and returned to normal resting levels at 48 hours. Net protein synthesis was significantly elevated at all time points.

IMPLICATIONS: Protein synthesis in muscle tissue can occur for up to 48 hours after a resistance training session. It is important to maintain adequate protein intake during this time to ensure that muscle has the resources to build new tissue. It also shows that the recovery/growth process can take up to 48 hours and it is important for individuals to allow at least 48 hours rest between bouts of resistance training for the same muscles.

The subjects in this study were untrained. Results may have been different for trained subjects. More research is needed on trained subjects. Research also needs to examine the length of the time period that protein synthesis continues at an elevated rate after a resistance training session. In this study, protein synthesis was still significantly higher than resting levels at 48 hours postexercise. Future research should look at a larger time window, i.e. 96 hours and longer.

1. Phillips, S.M., K.D. Tipton, A. Aarsland, S.E. Wolf, and R.R. Wolfe. Mixed muscle protein synthesis and breakdown after resistance exercise in humans. Am. J. Physiol. 273(1):E99-107. 1997.

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[syxxnutz]

This is the part that I understand. What I am asking is what happens if the intensity is dropped? I have a hard time believing that by moving books all day at my job I am increasing protein synthesis significantly. At what point of exertion is there a dropoff in synthesis? If I am unable to perform up to par in a weight training session will the same amount of synthesis occur? Is there some sort of percentage decrease as intensity drops?

Also, this study used untrained subjects. I am trained.

Thank you for the time you spent on the reply, but it doesn't really answer my question.