Tag Archives: muscle growth
Shoulder Press Effectiveness: Dumbbells vs Barbell and Seated vs Standing
There are many different ways 
to perform exercises and there is much debate about whether using dumbbells or a barbell for the same basic movement is more effective. To make matters even more complicated, many exercises can be performed both seated or standing. To determine the effects of these variables on training effectiveness for both muscle strength and muscle activation, scientists from Norway performed a study investigating the Shoulder Press exercise. In this study they investigated the effects of performing the shoulder press exercise with dumbbells vs barbells and seated vs standing.
How deep should you squat? The effect of squat depth on muscle activity
(10-22-2013) Proper technique during an exercise is very
important for good training results. This especially holds true for free weight exercises such as the squat. An important part of exercise technique is the Range of Motion (ROM). To see what the effect of squat depth is on muscle activation during the squat exercise, researchers performed the following study.
Testosterone
Testosterone is an androgen (male sex hormone) that promotes the development of secondary male characteristics during puberty. These include characteristics as a deeper voice, facial hair and an increase in muscle mass. Testosterone stimulates, directly (through testosterone receptors on muscle fibers), and indirectly, (through stimulating Growth Hormone production in the pituitary), hypertrophy. The increase in muscle mass caused by testosterone increases muscle strength. However this is not the only reason muscle strength increases. Testosterone can also bind with receptors on neurons (nerve cells), where it influences the production of neurotransmitter and the structure of nerve cells. Testosterone increases strength not only by increasing muscle mass but by improving muscle activation as well.
Testosterone is primarily produced in the testicles in men, and in the ovaries and adrenal glands in women. Men produce 15-20 times more testosterone than women, and the effect of different training protocols is greater on testosterone levels in men as well. In women, testosterone levels are hardly influenced by strength training or other forms of exercise, which partly explains the lower potential in women for increasing muscle mass.
In addition, an artificial form of testosterone (androgenic anabolic steroids) is used to stimulate muscle strength, hypertrophy and contraction speed, to increase performance in sports and athletic events. Most athletic organizations have banned the use of androgenic anabolic steroids and athletes who are caught using them risk suspension. Moreover, the use of androgenic anabolic steroids increases risk of developing cardiovascular disease and several forms of cancer.
References:
– Baechle, T.R., Earle, W.R. (2008). Endocrine Responses to Resistance Exercise. Essentials of Strength Training and Conditioning. Third Edition. USA. Human Kinetics. -Wilmore, J.H., Costill, D.L., Kenney, W.L. (2008). Ergogenic Aids and Sport. Physiology of Sport and Exercise Fourth Edition. USA Human Kinetics.
Hypertrophy
Hypertrophy 
is the process of growing tissues. In exercise physiology it normally refers to muscle hypertrophy or the increase of muscle mass. Muscle hypertrophy as a result of training is caused by an increase of cross section of themuscle fibers which form the muscle. This increase is caused by an increase in net protein production.