10 g, ça fait rien
Timing Of Post-exercise Protein Ingestion Alters Anabolic Signaling During
Prolonged Recovery
Medicine & Science in Sports & Exercise: May 2011 - Volume 43 - Issue 5 - p 136
Areta, Jose L; Burke, Louise M.
Muscle protein synthesis (MPS) is synergistically enhanced by resistance exercise and
feeding with mRNA translation initiation being a critical regulatory step. Previous
studies indicate 20 g of protein immediately after resistance exercise maximally
stimulates MPS during the early recovery period. However, no studies have examined
the effect of manipulating the quantity and timing of protein ingestion on anabolic
signaling over a whole day.
PURPOSE:To determine the time-course of anabolic signaling during prolonged
recovery from resistance exercise.
METHODS: 24 resistance trained men were randomly assigned to one of three groups.
Each reported to the laboratory following 72 h diet/activity control and an overnight
fast. Immediately following leg extension exercise (4 × 10 @ 80% 1repetition
maximum, 3 min recovery)
1) one group (PULSE) consumed an 8 × 10 g (125 mL) whey protein isolate drink at
1.5 h intervals;
2) an intermediate group (INT) consumed 4 × 20 g (250 mL) every 3 h;
3) and the final group (BOLUS) received 2 × 40 g (500 mL) 6 h apart during 12 h
passive recovery.
Muscle biopsy samples from vastus lateralis were taken at rest before exercise and 1, 4,
6, 7 and 12 h post-exercise. p70S6K Thr389 phosphorylation was measured as a
marker of translation initiation for MPS.
RESULTS:
BOLUS ingestion increased phosphorylation of p70S6K Thr389 above rest only at 1 h
(~20 fold) and 7 h post-exercise (~12 fold; both p<0.05).
INT feeding also increased Thr389 phosphorylation compared to rest at the 1 h time-
point during recovery (~12 fold, p<.05) and this effect was still evident 4 h post-
exercise (~8 fold, p<0.05) but not at any later time points.
In contrast, there were no differences in phosphorylation with PULSE. Moreover, the
phopshorylation with BOLUS and INT ingestion was greater than PULSE 1 h post-
exercise (P<0.05).
CONCLUSIONS: Pulse feeding (10 g) appears to have only modest capacity for
activating translation. In contrast, Bolus (40 g) feeding may induce transient,
repeatable activation of translational machinery while Intermediate ingestion (20 g)
extends the early, but not late, anabolic response. We show that altering the quantity
and timing of protein ingestion generates different anabolic signaling responses during
extended recovery from resistance exercise.
