Even if your focus is on a particular body part, say getting flat abs or losing fat around the hips, it's important to work all your muscle groups. Spot reduction doesn't work, so doing crunches for your abs or leg lifts for your thighs isn't going to help you achieve your goal. What does work is building more lean muscle tissue and burning more calories.
In weight training, as with most forms of exercise, there is a tendency for the breathing pattern to deepen. This helps to meet increased oxygen requirements. Holding the breath or breathing shallowly is avoided because it may lead to a lack of oxygen, passing out, or an excessive build up of blood pressure. Generally, the recommended breathing technique is to inhale when lowering the weight (the eccentric portion) and exhale when lifting the weight (the concentric portion). However, the reverse, inhaling when lifting and exhaling when lowering, may also be recommended. Some researchers state that there is little difference between the two techniques in terms of their influence on heart rate and blood pressure.[8] It may also be recommended that a weight lifter simply breathes in a manner which feels appropriate.
However, caffeine does not negate the benefits of creatine loading when not coingested, but just taken before exercise in the same dosage.[593] This result indicates that loading creatine without caffeine on a daily basis, but saving caffeine for select workouts, may be an effective strategy, as creatine does not adversely affect caffeine’s ergogenic effects[593][594] and may enhance creatine’s effectiveness in anaerobic exertion if the two compounds are alternated.[595]
The shortest and most preliminary study noted that, over the short term, creatine delivers on its expected improvement in physical strength. However, longer studies that measure the rate of loss for muscle function (deterioration of muscular capacity that is known to occur with ALS) have repeatedly failed to find a benefit with creatine supplementation.
Kerksick, C. M., Wilborn, C. D., Campbell, W. I., Harvey, T. M., Marcello, B. M., Roberts, M. D., Parker, A. G., Byars, A. G., Greenwood, L. D., Almada, A. L., Kreider, R. B., and Greenwood, M. The effects of creatine monohydrate supplementation with and without D-pinitol on resistance training adaptations. J.Strength.Cond.Res. 2009;23(9):2673-2682. View abstract.
A quantitative, comprehensive scientific summary and view of knowledge up to 2007 on the effects of creatine supplementation in athletes and active people was published in a 100 citation review position paper by the International Society of Sports Nutrition[5]. More recent literature has provided greater insight into the anabolic/performance enhancing mechanisms of creatine supplementation [15,25] suggesting that these effects may be due to satellite cell proliferation, myogenic transcription factors and insulin-like growth factor-1 signalling [16]. Saremi et al [26] reported a change in myogenic transcription factors when creatine supplementation and resistance training are combined in young healthy males. It was found that serum levels of myostatin, a muscle growth inhibitor, were decreased in the creatine group.

These supplements can vary considerably from product to product in ingredients, serving sizes, and more. But the goal of each of them is generally quite similar. Most bodybuilding supplements are designed to help stimulate new muscle growth, cut away excess fat, and improve the recovery process so that you can get the most out of each trip to the gym.
Men appear to have higher active creatine-kinase systems, and racial differences favor black people over hispanic people over white people in terms of the activity of the creatine-kinase system. This system is more variable in men, independent of supplementation. Exercise may increase the activity of the creatine-kinase system independent of supplementation.
No need to worry! This myth that caffeine counteracts creatine came from the simple, but wrong logic that because caffeine accelerates the nervous system and uses more water, it would counteract creatine because creatine helps your body retain water. While both of these statements are true, it does not mean they “cancel” eachother out, all that it means is that your body will be able to stay hydrated longer if you are taking creatine and caffeine opposed to just taking caffeine.
Although research is underway, doctors do not know the long-term health effects of taking creatine supplements, especially in children who are still growing. Because of these unknown risks, children and adolescents younger than 18 years and pregnant or nursing women should never take creatine supplements. People with kidney problems also should never take creatine supplements.
It’s important to remember that since everybody is different, these estimates are just that. How the numbers work out for each person will definitely vary. So many factors—like genetics, hormones, sleep, and diet—can change the rate at which our bodies burn calories. And some people may have a harder time than others when it comes losing fat or gaining muscle—again, there are so many factors at play and our body chemistries are all different. Strength training is important for many, many, many other reasons (more on that later), but if you’re looking to increase your metabolism, it’s important to have realistic expectations and know that strength training can make a difference, but probably won’t drastically affect how many calories you burn from one day to the next.
In otherwise healthy bodybuilders, supplementation of creatine at 5g either immediately before or after a weight training session (with no directive on days without training) over the course of four weeks noted that while both groups improved, there was no significant difference between groups overall.[384] This null result has been found in another study with 0.1g/kg creatine thrice weekly over 12 weeks in otherwise healthy adults.[385] It has been suggested that post-workout timing may be favorable (based on magnitude-based inference) since more individuals experience benefits with post-workout when compared to pre-workout despite no whole-group differences.[384] 
Drink plenty of water throughout the day, especially in the hours leading up to your workout. This can help you feel full and reduce hunger pangs. During training, drink about 8 ounces every 15-20 minutes, more when it's hot and humid. The reason is simple: Your performance quickly begins to suffer when the body is dehydrated just 1%-–2%. And if you wait till you feel thirsty, you've waited too long. A flavorful, low-calorie sports drink is a great way to hydrate. Try drinking fluids stored at cooler temperatures; studies show that people consume more when the liquid is colder.
However, a much more accurate determination of how much fluid is necessary can be made by performing appropriate weight measurements before and after a typical exercise session, to determine how much fluid is lost during the workout. The greatest source of fluid loss during exercise is through perspiration, but as long as your fluid intake is roughly equivalent to your rate of perspiration, hydration levels will be maintained.[14]
Despite the popularity of creatine among young people, there has been very little research conducted in children under age 18. Of those studies, a few have suggested a positive effect but the overall evidence is inconclusive. In one study, teenage swimmers performed better after taking creatine; in another study, it helped high school soccer players sprint, dribble, and jump more effectively.
Safety. Excess quantities of antioxidants may produce a ‘pro-oxidant’ effect, which is the opposite of what you would take these supplements for. The Australian Institute of Sport recommends that antioxidant vitamin supplements only be taken for a period of a few weeks while the body adjusts to stressful circumstances. Excess vitamin C may promote excess iron absorption, which may not be healthy for everyone.
Some ingredients found in dietary supplements marketed for bodybuilding or performance enhancement—such as whey protein, creatine, and caffeine—generally aren’t associated with any serious safety concerns (when used appropriately). However, they still have the potential for side effects. Before you take any dietary supplement, talk to your healthcare provider. You also can read the articles below about some of these ingredients:
In 1990, professional wrestling promoter Vince McMahon announced that he was forming a new bodybuilding organization named the World Bodybuilding Federation (WBF). McMahon wanted to bring WWF-style showmanship and bigger prize money to the sport of bodybuilding. A number of IFBB stars were recruited but the roster was never very large and featured the same athletes competing; the most notable winner and first WBF champion was Gary Strydom. McMahon formally dissolved the WBF in July 1992. Reasons for this reportedly included lack of income from the pay-per-view broadcasts of the contests, slow sales of the WBF's magazine Bodybuilding Lifestyles (later WBF Magazine), and the expense of paying multiple six-figure contracts while producing two TV shows and a monthly magazine.
Prohormones are precursors to hormones and are most typically sold to bodybuilders as a precursor to the natural hormone testosterone. This conversion requires naturally occurring enzymes in the body. Side effects are not uncommon, as prohormones can also convert further into DHT and estrogen. To deal with this, many supplements also have aromatase inhibitors and DHT blockers such as chrysin and 4-androstene-3,6,17-trione. To date most prohormone products have not been thoroughly studied, and the health effects of prolonged use are unknown. Although initially available over the counter, their purchase was made illegal without a prescription in the US in 2004, and they hold similar status in many other countries. They remain legal, however, in the United Kingdom and the wider European Union. Their use is prohibited by most sporting bodies.