One rat study that compared male and female rats and used a forced swim test (as a measure of serotonergic activity of anti-depressants[227]) found that a sexual dimorphism existed, and females exerted a serotonin-mediated anti-depressant response while male rats did not.[228] It appears that these anti-depressive effects are mediated via the 5-HT1A subset of serotonin receptors, as the antidepressant effects can be abolished by 5-HT1A inhibitors.[229]
Heath suggests incorporating dropsets into your training routine by immediately decreasing the weight and repping out again to failure. “Dropsets overload the muscle with shorter rest periods and increasing volume which you need to grow,” says Heath. “That overload improves your body’s abilities to utilize more nutrients, natural growth hormone, and natural testosterone into those areas and makes the supplements you take more effective.” Heath’s favorite way to do dropsets is on a pin-loaded machine since it’s faster to switch weights.
Creatine, the amino acid, naturally helps your body produce more adenosine triphosphate, or ATP, a small molecule that’s actually your body's primary energy source. But research shows that your body is only capable of storing enough ATP for 8 to 10 seconds of high-intensity exercise — and after that, it needs to produce new ATP for you to continue. (9)
After all, if you’re doing more reps in a set, the weight would obviously be lighter and the intensity level lower. If you’re doing fewer reps in a set, the weight is obviously heavier and the intensity is higher. In addition, how close you come to reaching failure – aka the point in a set when you are unable to complete a rep – also plays a role here.

^ Jump up to: a b c d e Cooper R, Naclerio F, Allgrove J, Jimenez A (July 2012). "Creatine supplementation with specific view to exercise/sports performance: an update". Journal of the International Society of Sports Nutrition. 9 (1): 33. doi:10.1186/1550-2783-9-33. PMC 3407788. PMID 22817979. Creatine is produced endogenously at an amount of about 1 g/d. Synthesis predominately occurs in the liver, kidneys, and to a lesser extent in the pancreas. The remainder of the creatine available to the body is obtained through the diet at about 1 g/d for an omnivorous diet. 95% of the bodies creatine stores are found in the skeletal muscle and the remaining 5% is distributed in the brain, liver, kidney, and testes [1].
It has also been noted that supplementing creatine (which reduces internal synthesis of creatine and methylation requirements) preserved folate and tetrahydrofolate status (42% and 23%),[312] which acted to preserve methyl groups for other processes. Despite this effect, global DNA methylation decreases by 22% (assessed by the 5-methylcytosine/cytosine ratio) following creatine supplementation, which is usually seen as an anti-cancer effect in developed mammals.[461] This study was unable to demonstrate why this reduction occured[461] and opposing effects have been noted in females with Rett syndrome supplementing 200mg/kg creatine for 1 year, during which global methylation increased, secondary to preserving other methyl donors.[462]
Athletic performance. Creatine seems to help improve rowing performance, jumping height, and soccer performance in athletes. But the effect of creatine on sprinting, cycling, or swimming performance varies. The mixed results may relate to the small sizes of the studies, the differences in creatine doses, and differences in test used to measure performance. Creatine does not seem to improve serving ability in tennis players.
Some of these medications that can harm the kidneys include cyclosporine (Neoral, Sandimmune); aminoglycosides including amikacin (Amikin), gentamicin (Garamycin, Gentak, others), and tobramycin (Nebcin, others); nonsteroidal anti-inflammatory drugs (NSAIDs) including ibuprofen (Advil, Motrin, Nuprin, others), indomethacin (Indocin), naproxen (Aleve, Anaprox, Naprelan, Naprosyn), piroxicam (Feldene); and numerous others.
Second, strength training has a much greater level of excess post-exercise oxygen consumption than aerobic exercise.  What does this mean?  When you finish a workout, your body needs to do a lot of work to replenish itself in order to bring itself back to a normal state (the way it was before you worked out).  This takes a lot of energy, and some studies have shown that it can boost your metabolism for up to 38 hours after you finish your workout.
One pilot study using 150mg/kg creatine monohydrate for a five day loading phase followed by maintenance (60mg/kg) for the remainder of the five weeks noted that supplementation was associated with fewer muscle symptoms and complaints alongside improved muscular function,[572] yet a later trial trying to replicate the obsevations using 150mg/kg daily for five weeks noted the opposite, that creatine supplementation exacerbated symptoms.[573]