The harder an exercise is – both in terms of technicality and physical/mental demand – the more rest there should usually be. So exercises like squats and deadlifts should have more rest between sets than exercises like leg extensions and leg curls. And exercises like various bench presses, shoulder presses, rows and pull-ups should have more rest between sets than bicep curls, tricep extensions, chest flies and lateral raises.
To combat steroid use and in the hopes of becoming a member of the IOC, the IFBB introduced doping tests for both steroids and other banned substances. Although doping tests occurred, the majority of professional bodybuilders still used anabolic steroids for competition. During the 1970s, the use of anabolic steroids was openly discussed, partly due to the fact they were legal.[9] In the Anabolic Steroid Control Act of 1990, U.S. Congress placed anabolic steroids into Schedule III of the Controlled Substances Act (CSA). In Canada, steroids are listed under Schedule IV of the Controlled Drugs and Substances Act, enacted by the federal Parliament in 1996.[10]

Creatine concentration is normally increased in the placenta and brain in the midgestation phase until term, with further increases in the brain for another two weeks after birth.[529] This effect appears to be due to the fetus itself expressing the creatine enzymes of synthesis (AGAT and GAMT) after 5% of the gestation time has passed (0.9 days in spiny mice).[529] Despite creatine normally suppressing AGAT when supplemented at high concentrations,[29][30] it appears that maternal supplementation of the diet with 5% creatine from the halfway point of pregnancy until term does not alter creatine synthesis in the newborn (no alterations in either AGAT or GAMT), nor does it affect the creatine transporter.[530] 
The largest determiner of your metabolic rate is actually your total body mass. “The more cells, even fat cells, in your body, the more furnaces you have burning at any given time,” Dr. Church says. Think of it this way: It takes more juice to charge your tablet than it does to charge your phone. People who are taller and have a larger bone structure, therefore, will have a higher BMR than people who are shorter and have a slimmer build. While you can control your body mass to some extent by gaining or losing weight, you can’t change your height or your bone structure. All in all, most of a person’s BMR is determined by genetic factors, Dr. Church says.
^ "The History of Weightlifting". USA Weightlifting. United States Olympic Committee. Archived from the original on 7 July 2013. Retrieved 3 September 2018. The genealogy of lifting traces back to the beginning of recorded history where man's fascination with physical prowess can be found among numerous ancient writings. A 5,000-year-old Chinese text tells of prospective soldiers having to pass lifting tests.
Entry into neural tissues in general is mediated by the secondary creatine transporter (CrT-2) known as SLC6A10,[186] which is the same transporter that is active in a male’s testicles.[145] CrT-2 belongs to the family of SLC6 transporters that act to move solutes across the membrane by coupling transport with sodium and chloride.[187][188] Genetic deletions in the 16p11.2 region, which encodes both SLC6A8[189] and SLC6A10[186] can result in severe mental retardation in humans and is one of the causes of “Creatine Deficiency Syndrome.” Creatine Deficiency Syndrome is not only caused by lack creatine transporter expression, however, as creatine synthesis is also critical for neural function.[190].[189] Retardation caused by defective creatine synthesis[31] can be reversed with creatine supplementation and dietary changes.[191]

For the bench press, start with a weight that you can lift comfortably. If you are a beginner, try lifting the bar along with 5lbs or 10lbs on each side. With arms at shoulder-width apart, grab onto the bar and slowly lower the bar until it's at nipple level; push up until your arms are fully extended upwards. Do 8–10 repetitions (reps) like this for three sets (3 x 8), adding additional weight each set. Once you have a few months of practice, slowly increase weight and go down to 6–8 reps per set, aiming to reach muscle failure at the end of the third set.

Cooke et al [41] observed positive effects of a prior (0.3 g/d kg BW) loading and a post maintenance protocol (0.1 g/d kg BW) to attenuate the loss of strength and muscle damage after an acute supramaximal (3 set x 10 rep with 120% 1RM) eccentric resistance training session in young males. The authors speculate that creatine ingestion prior to exercise may enhance calcium buffering capacity of the muscle and reduce calcium-activated proteases which in turn minimize sarcolemma and further influxes of calcium into the muscle. In addition creatine ingestion post exercise would enhance regenerative responses, favoring a more anabolic environment to avoid severe muscle damage and improve the recovery process. In addition, in vitro studies have demonstrated the antioxidant effects of creatine to remove superoxide anion radicals and peroxinitrite radicals [42]. This antioxidant effect of creatine has been associated with the presence of Arginine in its molecule. Arginine is also a substrate for nitric oxide synthesis and can increase the production of nitric oxide which has higher vasodilatation properties, and acts as a free radical that modulates metabolism, contractibility and glucose uptake in skeletal muscle. Other amino acids contained in the creatine molecule such as glycine and methinine may be especially susceptible to free radical oxidation because of sulfhydryl groups [42]. A more recent in vitro study showed that creatine exerts direct antioxidant activity via a scavenging mechanism in oxidatively injured cultured mammalian cells [43]. In a recent in vivo study Rhaini et al [44] showed a positive effect of 7 days of creatine supplementation (4 x 5 g CM 20 g total) on 27 recreational resistance trained males to attenuate the oxidation of DNA and lipid peroxidation after a strenuous resistance training protocol.
Recommended Dose: 3-6 grams before or during exercise. A ratio of two parts leucine to one part each of isoleucine and valine appears to be most beneficial. As Krissy Kendall, PhD, explains in "The Top 7 Supplements to Boost Endurance Performance," BCAAs can be just as effective for endurance athletes like runners, rowers, and cyclists as they can be for lifters and bodybuilders.
A study showed that 100mg/kg creatine monohydrate daily over four months supplemented by boys with DMD is able to enhance handgrip strength in the dominant hand only (less than 10% increase) and increase whole-body lean mass. While the trend toward whole body strength reduction seen in placebo was ablated and there was no interaction with corticosteroids,[560] this study failed to find an influence on activities of daily living or lung function.[560] Elsewhere in children not on corticosteroids with DMD, supplementation of 5g creatine for eight weeks was confirmed to increase muscular phosphocreatine content[554] and according to a manual muscle test (MMT) there was a significant improvement in muscular function relative to placebo, with more parents reporting benefit with creatine (53.8%) relative to placebo (14%).[554]
Creatine supplementation appears to attenuate decreases in GLUT4 expression seen with immobility and may increase GLUT4 expression during exercise. While it seems capable of increasing GLUT4 during resting conditions, it has failed to reach significance, suggesting that creatine supplementation works best with some stimuli associated with exercise.
Creatine is a hydrophilic polar molecule that consists of a negatively charged carboxyl group and a positively charged functional group [64]. The hydrophilic nature of creatine limits its bioavailability [65]. In an attempt to increase creatines bioavailability creatine has been esterified to reduce the hydrophilicity; this product is known as creatine ethyl ester. Manufacturers of creatine ethyl ester promote their product as being able to by-pass the creatine transporter due to improved sarcolemmal permeability toward creatine [65]. Spillane et al [65] analyzed the effects of a 5 days loading protocol (0.30 g/kg lean mass) followed by a 42 days maintenance phase (0.075 g/kg lean mass) of CM or ethyl ester both combined with a resistance training program in 30 novice males with no previous resistance training experience. The results of this study [65] showed that ethyl ester was not as effective as CM to enhance serum and muscle creatine stores. Furthermore creatine ethyl ester offered no additional benefit for improving body composition, muscle mass, strength, and power. This research did not support the claims of the creatine ethyl ester manufacturers.
Take time to rest. To give your muscles time to recover, rest one full day between exercising each specific muscle group. You might choose to work the major muscle groups at a single session two or three times a week, or plan daily sessions for specific muscle groups. For example, on Monday work your arms and shoulders, on Tuesday work your legs, and so on.
High extracellular creatine concentrations induce the expression of a factor that inhibits the creatine transporter (CrT). To date, neither the identity of nor mechanism for this putative CrT-suppressing factor has come to light. Future studies that are able to identify this creatine transport-suppressing factor and how it works may provide valuable insight into possible supplementation strategies that might be used to increase creatine uptake into muscle cells.
Using too much weight, too soon; always start lower than your expected ability and work your way up that first workout. If your form suffers, you are swinging the weight, or using momentum, this indicates you may be using too much weight. Greater momentum increases the potential for injury and reduces the effectiveness to the muscle group being targeted.