Sleep promotes repair and restoration.  Peter Res from Maastricht University Medical Center, and colleagues, found that consuming 20 grams of casein protein 30 minutes before bedtime promoted protein synthesis more than a placebo (fake protein).  The test subjects performed a vigorous bout of weight training at 8:00 p.m.  The supplement increased the rate of protein synthesis by 21 percent and boosted the overall protein balanced by more than 100 percent.  The researchers used sophisticated isotopic labeling methods to accurately measure the rate of protein synthesis.

This was an important study for bodybuilders.  After weight training, consuming a protein supplement shortly before bed will promote recovery and maximize protein synthesis.  (Medicine Science Sports Exercise,  44:  1560-1569, 2012)

Prolonged muscle contraction is the most important stimulus for increasing muscle size, according to researchers from McMaster University in Canada.  They studied the effect of a single workout using either slow reps (6 seconds up and 6 seconds down) or fast reps (1 second up and 1 second down).  They used a light load of 30 percent of 1 repetition maximum.  The rate of protein synthesis was greatest during the slow repetitions.  Maximizing time under tension is the best way to make muscles grow.  However, because of the importance of neural control, slow reps are not the best way to gain strength, particularly in well-trained athletes.  (Journal of Physiology, 590:  351 – 362, 2012)

Disturbed sleep patterns can trigger abdominal obesity, sudden cardiac death, anxiety and cardiac arrhythmias.  Many studies found a link between decreased testosterone levels and reduced sleep in men.  Men with the lowest testosterone levels had shorter periods of phases 3 and 5 sleep, the deepest periods of sleep.  Deep sleep phases disappeared completely in some men over 60 with low testosterone levels.  German scientists found that sleep deprivation during the early part of the sleep cycle had little effect on testosterone.  Sleep deprivation later in the sleep cycle caused marked decreases in testosterone.  Testosterone is important for synchronizing brain activity during sleep.  Low testosterone levels disturb brain function and interfere with sleep.  The effects of supplemental testosterone on sleep patterns are not known.  (Clinical Endocrinology, published online May 9, 2012)

Amino acids are important for muscle growth because they serve as the building blocks for protein synthesis.  The amino acid leucine is particularly important because it serves as a key chemical for turning on the mTOR biochemical pathway of protein synthesis.  A University of Illinois study using rats showed that the leucine content of various food proteins was the most important factor determining the food’s effect on protein synthesis.  They examined the effects of wheat, soy, egg and whey protein, which contained 6.8, 8.0, 8.8 and 8.9 percent leucine.  The leucine content of foods is critical for promoting muscle protein synthesis.  (Nutrition & Metabolism, 9:  67, 2012)