From Ergo Log
It makes precious little difference whether you put whey or casein in the shakes that you drink before and after a strength training session. Sports scientists at the University of Mary Hardin-Baylor draw this conclusion from a study in which they gave 16 female basketball players whey or casein before and after their strength workouts.
Casein is made up of long chains of amino acids that don't dissolve in water. In the stomach casein forms a mass that is digested relatively slowly. The amino acids appear gradually in the blood after ingesting casein.
Whey on the other hand consists of short amino acid chains that do dissolve in water. The amino acids appear quickly in the blood after ingesting whey, but the 'amino acid peak' is shorter.
For this reason trainers advise athletes to use fast whey when working out and casein to bridge longer periods where no intensive exercise is undertaken. During and immediately after intensive exertion, muscles benefit from a high concentration of amino acids in the blood.
The researchers decided to test this theory on female basketball players who did weight training four times a week and short 'sport specific conditioning' sessions with 'agility, jumping and sprint work' three times a week.
Half of the women were given 24 g whey half an hour before the training session and again just afterwards. The other half were given the same amount of casein before and after the session.
Before the supplementation started, and for eight weeks afterwards, the researchers measured the women's body composition. The figure below shows that the women who had been given whey had lost a tiny amount more fat and had gained a tiny amount more lean body mass than the women who had been given casein. However, the differences between the two groups were not significant.
The figure below shows the increase in maximal strength in both groups. The whey group did minimally better than the casein group but, again, the differences are not significant.
Female athletes who want to boost their performance level by doing strength training can benefit from protein supplementation, the researchers conclude. "There does not appear to be a difference in the performance enhancing effects of whey versus casein proteins, and both prove to be beneficial to athletic performance in female athletes for both strength and body composition", they write.
J Sports Sci Med. 2013 Mar 1;12(1):74-9.