^ Southren AL, Gordon GG, Tochimoto S, Pinzon G, Lane DR, Stypulkowski W (May 1967). "Mean plasma concentration, metabolic clearance and basal plasma production rates of testosterone in normal young men and women using a constant infusion procedure: effect of time of day and plasma concentration on the metabolic clearance rate of testosterone". The Journal of Clinical Endocrinology and Metabolism. 27 (5): 686–94. doi:10.1210/jcem-27-5-686. PMID 6025472.
Gains will differ from one individual to another depending on body size and level of experience in the gym. To make sure you're gaining muscle, not fat, don't just consider your scale weight. Instead, rely on what you see in the mirror and use a tape measure twice a month to keep track of your waist and hips (you don't want to gain there) as well as your biceps, chest and quads. Also, don't think that you have to gain a set amount of weight each and every week. "Your mass gain doesn't have to be uniform," Aceto explains. That means you can gain 1/2 pound one week and 1 1/2 the next, perhaps none the third week and still remain on course. "Expecting uniform gains ignores the intricate makeup of the body and the way it gains mass - or loses fat - which is by no means in linear fashion," adds Aceto.
A 2011 survey of 33 supplements commercially available in Italy found that over 50% of them exceeded the European Food Safety Authority recommendations in at least one contaminant. The most prevalent of these contaminants was creatinine, a breakdown product of creatine also produced by the body. Creatinine was present in higher concentrations than the European Food Safety Authority recommendations in 44% of the samples. About 15% of the samples had detectable levels of dihydro-1,3,5-triazine or a high dicyandiamide concentration. Heavy metals contamination was not found to be a concern, with only minor levels of mercury being detectable. Two studies reviewed in 2007 found no impurities.
Do a single set of repetitions. Theories on the best way to approach weight training abound, including countless repetitions and hours at the gym. But research shows that a single set of exercise with a weight that fatigues your muscle after about 12 to 15 repetitions can build muscle efficiently in most people and can be as effective as three sets of the same exercise.
Walnuts are a dietary paradox – or at least they appear that way. As you probably know, walnuts are very calorically dense, mainly because of their fat content. Just one ounce of walnuts – that is about 12-14 halves – contains 185 calories. If you’ve ever tracked your food intake, you know that sort of thing can add up very quickly, especially if you’re just grabbing handfuls and not measuring.
One limitation of many free weight exercises and exercise machines is that the muscle is working maximally against gravity during only a small portion of the lift. Some exercise-specific machines feature an oval cam (first introduced by Nautilus) which varies the resistance, so that the resistance, and the muscle force required, remains constant throughout the full range of motion of the exercise.
Kilduff, L. P., Georgiades, E., James, N., Minnion, R. H., Mitchell, M., Kingsmore, D., Hadjicharlambous, M., and Pitsiladis, Y. P. The effects of creatine supplementation on cardiovascular, metabolic, and thermoregulatory responses during exercise in the heat in endurance-trained humans. Int J Sport Nutr Exerc Metab 2004;14(4):443-460. View abstract.