Athletes build up more muscle mass and strength if they ingest 15 g whey before a strength training session and another 15 g after they've finished. Researchers at the University of Jyvaskyla in Finland discovered that the stimulatory effect of whey at molecular level has nothing to do with myostatin inhibition, but everything to do with activation of the growth enzyme cdk2.
Scores of studies show that strength training is more effective when combined with extra protein, for example in the form of whey. That's logical, as trained muscles need extra amino acids for recovery and growth. The Finns were curious as to whether they could demonstrate the effect of extra proteins at the molecular level.
Strength training reduces the production of the muscle-inhibiting protein myostatin, and the Finns speculated that ingesting whey proteins close to a workout might further suppress the production of myostatin.
The researchers got ten males in their twenties to do nothing for a period of 21 weeks [Control]. Another group of ten young men did strength training twice a week during the same period. The researchers got the men to do a basic exercise programme with leg-presses, leg-extensions, leg-curls, leg-adductions, leg-abductions, calf-raises, plus basic exercises for the abdominal muscles, lower back, chest, shoulders, upper back and upper arms. The group were given a placebo during the workout [Placebo].
A third group of eleven young men followed the same regime, but were given a shake containing 15 g whey [Protein] immediately before and after the strength training session.
Using MRI technology the Finns showed that after 21 weeks the men in the Protein group had built up bulkier muscles than the men in the Placebo group. The figure below shows that the increase in the circumference of the quadriceps vastus lateralis was faster in the men that were given whey before and after their strength training sessions.
The whey supplementation also resulted in an increase in static and dynamic strength.
The whey supplementation did not lead to a further decrease in myostatin production, however. It seemed that the whey supplementation actually reduced the decrease. So the added value of whey supplementation during strength training has nothing to do with myostatin, but has something to do with the cell-cycle kinase cycline-dependent kinase 2 [cdk2]. This is a protein that plays a key role in the life cycle of cells. Cdk2 is involved in the growth of young cells.
"The increase in cdk2 gene expression suggests a higher proliferating cell activation response with protein supplementation that can be advantageous for muscle hypertrophy", the Finns write.