Diderisken et al. had their subjects (again: 15 elderly men and 9 elderly women; age 68 ± 1 years, range 61–80 years) perform 5 sets of eight repetitions at 80% of 1 RM in both unilateral knee-extension and bilateral leg-press with 3 min of rest between sets and measured muscle myofibrillar and collagen fractional synthesis rates (FSR) by a primed continuous infusion of l-[1-13C]leucine using labeled proteins during a 6-h recovery period. Other than the researchers had expected the fractional protein synthesis rates did not depend on form or timing of the 0.45 g/kg LBM supplemental protein their subjects consumed.
No differences were observed in muscle myofibrillar and collagen FSR with Whey [administered post workout] compared with CasPost [casein post workout], and it did not differ between CasPre [casein pre workout] and CasPost.This being said, secondary data on the leucine concentration does support the well-established advice to prefer whey over casein in the (non-existent) "post workout window":
The plasma leucine concentrations were increased during the entire post-exercise periods in CasPre, CasPost, and Whey compared with the basal levels. The leucine concentrations reached a peak of 227 ± 11, 282 ± 17, and 490 ± 32 μmol/L in CasPre, CasPost, and Whey, respectively. [...] The total leucine response expressed as the AUC in the time period 15–390 min after the resistance exercise bout was significantly higher in Whey compared with all the other groups (P<0.05), higher in CasPost compared with CasPre (P<0.05), and lower in Control than in the other groups (P<0.01).This very ability of whey protein to "spike" leucine levels post workout go hand in hand with findings from previous studies (in rodents, as well as human subjects) that suggest a slight yet significant advantage of whey over casein in view of the nutritional amelioration of exercise induced muscle anabolic responses. It is yet worth mentioning that both additional casein pre-ingestion and casein (co-)ingestion post-workout could be valuable strategies to prolong the increase in total (TAA) and essential (EAA) amino acids. This hypothesis is supported by the following findings:
[...] plasma TAA concentrations were increased in CasPre (15–150 min), CasPost (30–60 min), and Whey (30–60 min) compared with the basal levels. The plasma EAA concentrations were increased in CasPre (30 min), CasPost (30–270 min), and Whey (30–60 min) compared with the basal levels.
|Figure 1: Nature already invented |
the perfect peri-workout drink: Milk!
(photo (cc) Chedid, Janine. 2004)
Well, that being said, guess who has already developed such a pre/post/peri-all-in-one-workout formula for you? Nature! The name? Milk! Milk is roughly 80% casein and 20% whey, has some additional carbs in it that will get you through your workout and is full of healthy minerals and vitamins that will help you recover even faster. Make it raw unpasteurized milk from the happy grass-fed cows of a local farmer and there will be little room for further improvements ;-)