AAOS does not endorse any treatments, procedures, products, or physicians referenced herein. This information is provided as an educational service and is not intended to serve as medical advice. Anyone seeking specific orthopaedic advice or assistance should consult his or her orthopaedic surgeon, or locate one in your area through the AAOS Find an Orthopaedist program on this website.
As a Bodybuilding specialist, you will learn training, recovery, motivation, and nutritional strategies to prepare you to work with bodybuilders. Upon completion of ISSA's Bodybuilding course, you will have the knowledge necessary to prepare an athlete for a high-level bodybuilding or physique competition. However, many clients will never go down that path but are looking for guidance on this practice; this course will provide essential information that can help you train the "everyday" clients who have specific goals. All trainers can benefit from the information in this bodybuilding course, not only individuals looking to enter the sport of bodybuilding!
Don’t take sets to the point of failure—where you absolutely can’t perform another rep. You should never get to where you’re turning purple and screaming like you’re getting interviewed by “Mean” Gene Okerlund before WrestleMania. Most of the time, you want to end your sets two reps before total failure. Not sure when that is? The moment your form breaks down, or you’re pretty sure it’s going to break down, end the set.
Do standard/oblique crunches. Lie down on a mat and position both arms behind your head without locking the hands. Bend your knees so that your feet are flat on the ground. Pushing the small of your back into the ground, slowly roll your shoulders off the ground only a couple of inches (not to a full sitting position). Don't use your momentum to help you up; use slow, regulated movements. Repeat 3 x 20.

^ Jump up to: a b c d Brosnan JT, da Silva RP, Brosnan ME (May 2011). "The metabolic burden of creatine synthesis". Amino Acids. 40 (5): 1325–31. doi:10.1007/s00726-011-0853-y. PMID 21387089. Creatinine loss averages approximately 2 g (14.6 mmol) for 70 kg males in the 20- to 39-year age group. ... Table 1 Comparison of rates of creatine synthesis in young adults with dietary intakes of the three precursor amino acids and with the whole body transmethylation flux 

A flat, atrophied butt doesn't just look bad in jeans or swimsuits—it’s also likely contributing to your tight hips and back problems. If not, it soon will be. That’s because a flat butt is a symptom of tight hips and hamstrings, the result of poor glutes activation. In an ideal world, they all work together to stabilize the pelvis and produce many years of fluid movement.

If you are somebody that is tired of not getting results, wants to avoid trial-and-error, or you just want to be told exactly what to do to reach your goals, check out our popular 1-on-1 coaching program. You’ll work with our certified NF instructors who will get to know you better than you know yourself and program your workouts and nutrition strategy for you.

Having a spotter nearby is particularly important when using free weights. Even someone in great shape sometimes just can't make that last rep. It's no big deal if you're doing biceps curls; all you'll have to do is drop the weight onto the floor. But if you're in the middle of a bench press — a chest exercise where you're lying on a bench and pushing a loaded barbell away from your chest — it's easy to get hurt if you drop the weight. A spotter can keep you from dropping the barbell onto your chest.
Now that you've got the training part down, it's time to stretch it out. (Can you say ahhh?) Stretching while your muscles are warm can help improve your flexibility, says Davis, not to mention it just feels phenomenal after you've pushed yourself hard. A light cool-down is also great for calming the nervous system. While dynamic stretches should be your go-to during a warm-up, the cool-down is where static stretching comes in—this means holding a stretch for 20-30 seconds. These four passive stretches will do nicely.
If your fitness goals are to get strong and build hard, visible muscle, then you’re going to want to train in three phases according to Heath. Strength, conditioning, and a blend of the two that works for you. “If you can get to the gym 4-5 days a week, that would be perfect,” he says. “You can still do chest/tri’s, back/bi’s, legs, shoulders, and make the fifth day a cleanup day, meaning focus on body parts you may be weaker in.” Check out Heath’s guide to finding your best muscle-building routine.
Creatine (/ˈkriːətiːn/ or /ˈkriːətɪn/[1] is an organic compound with the nominal formula (H2N)(HN)CN(CH3)CH2CO2H. This species exists in various modifications (tautomers) in solution. Creatine is found in vertebrates where it facilitates recycling of adenosine triphosphate (ATP), the energy currency of the cell, primarily in muscle and brain tissue. Recycling is achieved by converting adenosine diphosphate (ADP) back to ATP via donation of phosphate groups. Creatine also acts as a buffer.[2]
When creatine supplementation is combined with heavy resistance training, muscle insulin like growth factor (IGF-1) concentration has been shown to increase. Burke et al [2] examined the effects of an 8 week heavy resistance training protocol combined with a 7 day creatine loading protocol (0.25 g/d/kg lean body mass) followed by a 49 day maintenance phase (0.06 g/kg lean mass) in a group of vegetarian and non-vegetarian, novice, resistance trained men and women. Compared to placebo, creatine groups produced greater increments in IGF-1 (78% Vs 55%) and body mass (2.2 Vs 0.6 kg). Additionally, vegetarians within the supplemented group had the largest increase of lean mass compared to non vegetarian (2.4 and 1.9 kg respectively). Changes in lean mass were positively correlated to the modifications in intramuscular total creatine stores which were also correlated with the modified levels of intramuscular IGF-1. The authors suggested that the rise in muscle IGF-1 content in the creatine group could be due to the higher metabolic demand created by a more intensely performed training session. These amplifying effects could be caused by the increased total creatine store in working muscles. Even though vegetarians had a greater increase in high energy phosphate content, the IGF-1 levels were similar to the amount observed in the non vegetarian groups. These findings do not support the observed correlation pattern by which a low essential amino acid content of a typical vegetarian diet should reduce IGF-1 production [33]. According to authors opinions it is possible that the addition of creatine and subsequent increase in total creatine and phosphocreatine storage might have directly or indirectly stimulated production of muscle IGF-I and muscle protein synthesis, leading to an increased muscle hypertrophy [2].
Honestly, I did a lot of research on this one, because I wanted to find a single group of people who should not strength train.  I even found studies on how strength training can be beneficial for paraplegics.  Not to mention it can be safe for children, adolescents, and pregnant women.  Obviously, you should take a break from strength training if you’re injured, and always check with your doctor before you start any sort of strength training program, but it’s natural for us, as humans, to move around and carry things.

Carbohydrates provide quick energy in an anaerobic environment (high-intensity exercise), while fats provide sustained energy during periods of high oxygen availability (low-intensity exercise or rest). The breakdown of carbohydrates, fats, and ketones produces ATP (adenosine triphosphate). When cells use ATP for energy, this molecule is converted into adenosine diphosphate (ADP) and adenosine monophosphate (AMP). Creatine exists in cells to donate a phosphate group (energy) to ADP, turning this molecule back into ATP.[20][21][22][23]
^ Jump up to: a b c d e f g h Momaya A, Fawal M, Estes R (April 2015). "Performance-enhancing substances in sports: a review of the literature". Sports Med. 45 (4): 517–531. doi:10.1007/s40279-015-0308-9. PMID 25663250. Wilson et al. [91] demonstrated that when non-resistance trained males received HMB pre-exercise, the rise of lactate dehydrogenase (LDH) levels reduced, and HMB tended to decrease soreness. Knitter et al. [92] showed a decrease in LDH and creatine phosphokinase (CPK), a byproduct of muscle breakdown, by HMB after a prolonged run. ... The utility of HMB does seem to be affected by timing of intake prior to workouts and dosage [97].
Gain mass: One of the most popular reasons for people to take body building supplements is to gain weight and that is why protein powder is much sought after. Protein is the building block of muscles and therefore, bodybuilders use protein powder to help repair muscles, speed recoveries and preserve muscle mass. They usually consume 1 to 2 grams of protein per pound of body weight every day. 
Prevents disease and degenerative conditions: Heart disease is the leading cause of death for both men and women; Strength training helps correct issues relating to cholesterol, high blood pressure, obesity, diabetes, and inactivity – all factors for heart disease. Cardiologists are even starting to recommend strength training for people who have suffered a heart attack as little as three weeks after the attack. Who knows, maybe one day your cardiologist will tell you to do some “cardio” and he’ll be referring to strength training!
“Compared to training for strength, intensity is going to drop during the hypertrophy phase of a program, with intensity sitting between 50 and 75 percent of the person’s 1RM, the maximum weight he or she can lift for one rep,” says Ava Fitzgerald, C.S.C.S., C.P.T., a sports performance coach with the Professional Athletic Performance Center in New York.
This is one of the best workouts for your hamstrings and glutes. Start in a standing position, feet shoulder-width apart. Hold the bar in front of you. Lower it to just below your knees. You can lower it further if you can keep a flat back and stable spine. Slowly return to the starting position. Keep the bar close to your body to protect your lower back.
Stand with your feet slightly wider than shoulder width with a kettlebell about a foot in front of you. With your weight in your heels, hinge at your hips while lowering your hands to the kettlebell handle. Grab the kettlebell with an overhand grip,  “Hike” the kettlebell back between your legs, catching the force of the moving kettlebell with your hips. Exhale as you swing the kettlebell forward by thrusting your hips, straightening your legs, and squeezing your glutes and abs. Once the kettlebell reaches chest height, inhale as you allow it to fall, and guide it back to the “hiked” position.
In isolated striatal cells (expressing creatine kinase), seven day incubation of 5mM creatine (maximal effective dose) appears to increase the density of GABAergic neurons and DARPP-32 (biomarker for spiny neurons[225]) with only a minor overall trend for all cells[226] and showed increased GABA uptake into these cells, as well as providing protection against oxygen and glucose deprivation.[226]
Even human studies can be misinterpreted or manipulated. A few years ago a then-esoteric trace mineral called boron was found to increase testosterone, but only in older women, as it turned out. When boron was tested in young men engaged in weight training, it proved worthless for increasing testosterone. That doesn't mean boron is useless; it helps the body use the minerals calcium and magnesium, and it appears to increase mental alertness.
How to do it: In general, your feet should be shoulder-width or slightly wider apart (if you’ve got a bigger frame go wider; if you’re smaller, go closer together), and your feet planted firmly on the floor, driving and emphasizing that heel drive. Stand tall. Depending on your preference or what’s available, hold a dumbbell in each hand (arms down at your sides); position yourself under a barbell with the bar against your traps for a back squat, and just over your chest for a front squat; hold a kettbell or dumbbell at your chest for goblet squats; wrap resistance bands under your feet and around your shoulders; or, use just your bodyweight to perform a basic squat.
Exercise is the original testosterone booster, and it’s one of the most powerful full-body hacks around. Men see a sharp increase in both testosterone and human growth hormone (HGH) after lifting weights, and the boost is greater with shorter rest time between sets (1 minute rest outperforms 3 minutes rest) [9]. With the shorter rest time, women also get a large boost in HGH.
There are many camps within the weight training fitness community. We have bodybuilders, Crossfit athletes, powerlifters, Olympic lifters, and strongman athletes just to name the most popular ones off the top of my head. One thing they all have in common is that they all use resistance to achieve a particular goal. They all also “share” particular exercises. Most resistance-training athletes do barbell squats, overhead presses and deadlifts. I can write pages of differences between each of the disciplines I listed above and I can also write quite a bit about their similarities but one form of resistance training is MORE different than the others. Bodybuilding is the only sport that judges the appearance of the athlete rather than their performance. This may be why bodybuilders tend to get poked at the most.
Some anti-aging physicians also use sublingual ( taken under the tongue) forms of non-bioidentical testosterone like oxandrolone. I took oxandrolone with a physician’s guidance for about two weeks, and I got pimples and hair loss. I quit and was bummed that it didn’t generate enough impact to write a blog post about it. I have continued to recommend bioidentical testosterone since.
Men's levels of testosterone, a hormone known to affect men's mating behaviour, changes depending on whether they are exposed to an ovulating or nonovulating woman's body odour. Men who are exposed to scents of ovulating women maintained a stable testosterone level that was higher than the testosterone level of men exposed to nonovulation cues. Testosterone levels and sexual arousal in men are heavily aware of hormone cycles in females.[46] This may be linked to the ovulatory shift hypothesis,[47] where males are adapted to respond to the ovulation cycles of females by sensing when they are most fertile and whereby females look for preferred male mates when they are the most fertile; both actions may be driven by hormones.
Most experts recommend starting with your larger muscle groups and then proceeding to the smaller muscle groups. The most demanding exercises are those performed by your large muscle groups and you will need your smaller muscles to get the most out of these exercises. But, don't feel limited by that. You can do your exercises in any order you like and changing the order is a great way to challenge yourself in different ways.

However, don’t despair over the poor reviews. There are other ways to achieve a testosterone booster for muscle gain. One of them is simply Vitamin D. A deficiency in this vitamin can lower your levels of testosterone. Furthermore, you can get a very natural boost simply by weightlifting and engaging in HIIT (High Intensity Interval Training) exercise. In addition, you should avoid some foods like soy and alcohol which can lower testosterone levels (11). Through these natural solutions and lifestyle changes, you can influence your hormone profile, creating a balance that’s more favorable for muscle growth.
Beta-alanine is a naturally occurring non-essential amino acid that comes into the body through foods that are rich in protein. The performance-enhancing aspect of beta-alanine (BA) is due to its ability to increase intra-muscular levels of carnosine. Increasing beta-alanine through supplementation may raise carnosine levels by over 60 percent in as quickly as four weeks.[6]
However, protein isn’t everything. Contrary to popular belief, carbohydrates and calories from fats are also important. To gain muscle, people who are slender or scrawny need to create a calorie surplus in order to bulk up. That means you need proteins and plenty of healthy carbs, vegetables and even some fats (think healthy fats like nuts, avocado, olive oil, etc.). Carbohydrates play a key role in building muscle. This macronutrient has gotten a bad rap for making people fat. However, if you work out properly, eating plenty of carbs is in your best interest. After training, it’s ideal to ingest some carbs in combination with protein to help replenish your muscles’ glycogen stores.
The maximum amount of creatine the body can store is about 0.3 gram per kilogram of body weight [6]. The creatine content of skeletal (voluntary) muscles averages 125 millimoles per kilogram of dry matter (mmol/kg/dm) and ranges from about 60 to 160 mmol/kg/dm. Approximately 60% of muscle creatine is in the form of PCr. Human muscle seems to have an upper limit of creatine storage of 150 to 160 mmol/kg/dm. Athletes with high creatine stores don't appear to benefit from supplementation, whereas individuals with the lowest levels, such as vegetarians, have the most pronounced increases following supplementation. Without supplementation, the body can replenish muscle creatine at the rate of about 2 g/day [7].
This claim has not been demonstrated at this time, and a recent comparative study of buffered creatine against basic creatine monohydrate found no significant differences between the two in 36 resistance trained individuals, in regard to the effects or the accumulation of creatine in muscle tissue.[71] There also were no significant differences in the amount of adverse side-effects reported.
Anti-depressive effects have been noted in woman with major depressive disorder when 5g of creatine monohydrate was supplemented daily for 8 weeks in combination with an SSRI. Benefits were seen at week two and were maintained until the end of the 8-week trial.[253] The improvement in depressive symptoms was associated with significantly increased prefrontal cortex levels of N-acetylaspartate, a marker of neuronal integrity,[254] and rich club connections, which refers to the ability of nerons to make connections to one another.[255]
How to do it: Lie flat on your back with your feet firmly planted on the floor, knees bent, as if you’re doing a standard bridge. Keeping one foot fixed to the ground, lift the other up, keeping the bend in your knee. Drive your hips up toward the ceiling, driving through your planted leg and using the raised leg to keep your pelvis even and balanced. Don’t let your non-working leg/side drop, Reames advises, and keep emphasizing the heel plant. Lower toward the ground, then repeat.
Using an ultra-pure and effective creatine formula, AI Sports' Micronized Creatine serves 5 grams of the purest creatine which can help the body to enhance the production of ATP and boost the growth as well as development of muscle. Along with promoting the increase of muscle mass, Micronized Creatine may also be able to build strength and improve performance while preventing the fatigue of muscle. Experience the enhancement that Micronized Creatine can provide to help level up your training sessions. Keep Reading »
Prevents disease and degenerative conditions: Heart disease is the leading cause of death for both men and women; Strength training helps correct issues relating to cholesterol, high blood pressure, obesity, diabetes, and inactivity – all factors for heart disease. Cardiologists are even starting to recommend strength training for people who have suffered a heart attack as little as three weeks after the attack. Who knows, maybe one day your cardiologist will tell you to do some “cardio” and he’ll be referring to strength training!
A commercially available pre-workout formula comprised of 2.05 g of caffeine, taurine and glucuronolactone, 7.9 g of L-leucine, L-valine, L-arginine and L-glutamine, 5 g of di-creatine citrate and 2.5 g of β-alanine mixed with 500 ml of water taken 10 minutes prior to exercise has been shown to enhance time to exhaustion during moderate intensity endurance exercise and to increase feelings of focus, energy and reduce subjective feelings of fatigue before and during endurance exercise due to a synergistic effect of the before mentioned ingredients [72]. The role of creatine in this formulation is to provide a neuroprotective function by enhancing the energy metabolism in the brain tissue, promoting antioxidant activities, improving cerebral vasculation and protecting the brain from hyperosmotic shock by acting as a brain cell osmolyte. Creatine can provide other neuroprotective benefits through stabilisation of mitochondrial membranes, stimulation of glutamate uptake into synaptic vesicles and balance of intracellular calcium homeostasis [72].
Another part of training isn't just doing the exercises, it's resting between the exercises. This comes with experience, but the general rule is, the higher the reps, the shorter the rest. So, if you're doing 15 reps, you might rest about 30 to 60 seconds between exercises. If you're lifting very heavy, say 4 to 6 reps, you may need up to two or more minutes.
A testosterone test is done if your doctor suspects that your depressive symptoms may be a result of testosterone deficiency. This test is usually done at a particular time of the day –usually in the morning between 7:00 a.m. and 10:00 a.m. This is because testosterone levels in the body vary with the time of the day, being highest in the morning. Before this test is scheduled, however, your doctor will ask you to discontinue certain medications which may affect the accuracy of the test.
Mini bands are becoming more popular and with good reason. They are a great way to get the glutes geared up for a workout. The best way to do them? Put the mini band around your feet – yes, your feet - and walk laterally, trying to move your upper body as little as possible. This is usually a pretty fail-safe way of getting a burn in that pocket muscle.

Creatine supplementation has been noted to improve general wellbeing and health status (assessed by St George’s Respiratory questionnaire[582]) of people with COPD over two weeks loading (17.1g daily with carbohydrates) and ten weeks of 5.7g maintenance.[579] The studies that failed to find improvements with creatine supplementation on muscular performance also failed to find improvements in this rating scale, relative to placebo.[580][581]
Electrolytes derive mainly from minerals in the diet and they maintain fluid balance and assist the nervous system to perform muscle contractions. Electrolytes are sodium, potassium, magnesium, calcium and chloride, bicarbonate, phosphate, sulfate. Exercisers are particularly dependent on sodium and potassium balance. Carbohydrates are important for fueling exercise, including vigorous weight training, and in post-exercise energy replacement nutrition. Carbohydrates, mostly sugars, are formulated in sports drinks with electrolytes such as sodium chloride and potassium and sometimes magnesium.
That being said, men aren’t the only ones who suffer from low testosterone levels. Women can also suffer from testosterone deficiency which can affect their overall well-being in addition to their sex drive. If you’re a woman or man concerned about your testosterone levels, in addition to using supplements like the ones below, you should contact your doctor who will be able to diagnose any deficiencies and recommend additional treatments.
"It'’s especially important to eat a carb- and protein-rich meal immediately after a workout," Aceto says. "Right after training, it turns out that your body is really lousy at taking carbohydrates and sending them down fat-storing pathways,"” he says. "So post-training, carbs will be sent down growth-promoting pathways instead."” And when these carbs are combined with a protein source, you'’ve got a strong muscle-feeding combination because carbohydrates help deliver the amino acids into muscles by boosting insulin levels. This anabolic hormone drives nutrients into the muscle cells and kick-starts the muscle-growth process.
Increasing creatine levels in skeletal muscle to 687% of baseline (0.5mM creatine, thought to be equivalent to 5g creatine[135]) doesn’t seem to per se increase glucose uptake, but increases glucose oxidation (140% of baseline)[341] which is due to a two-fold increase in the activity of α1 and α2 subunits of AMPK, a potency comparable to 1mM of the reference drug AICAR.[341] Glucose uptake associated with AMPK has indeed been noted in diabetic people who are undergoing physical exercise[342] and in contracting skeletal muscle cells,[153][330] but according to rat[343][344][345] and in vitro studies of cells not being contracted,[341] this is not a per se effect of non-exercising tissue but an augmentation of exercise-induced glucose uptake.
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]
2-4 Minutes Rest: Ideal for “tension exercises,” which includes most primary compound exercises. I personally take 3 minutes for the big stuff, sometimes going into the 3-4 minute range depending on exactly what I’m doing and what I feel like I need at the time. Since making strength gains is the main focus of these exercises, longer rest periods like this will be optimal for making it happen.

Holding a kettlebell in your left hand, stand on your right foot and lift your left foot off the ground.. Keeping your weight in your midfoot to heel, inhale as you hinge at your hips and slightly bend your knee to push your butt backward. Keep your shin vertical and hips squared forward. Exhale as you drive through your heel to return to standing. Do 10-12 reps. Switch sides.


Diet – To boost your body’s testosterone levels, you need to reduce your intake of foods that promote an increase in your belly fat. Increase in belly fat promotes the activity of an enzyme called aromatase which converts testosterone to the female sex hormone, estrogen. Therefore, the greater the amount of belly fat you have, the more your level of testosterone reduces. In addition, increase your intake of heart-healthy foods such as fiber from whole grains, lean white meat, fresh fruits, and vegetables and reduce your intake of red meat and animal fat.
Due to this relative deficiency-state in vegetarians and vegans, some aspects of creatine supplementation are seen as more akin to normalizing a deficiency, rather than providing the benefits of supplementation. In young vegetarians, but not omnivores, creatine supplementation can enhance cognition.[60][61] The increased gain in lean mass may be more significant in vegetarians, relative to omnivores.[59] Supplementation of creatine in vegetarians appears to normalize the gap in storage between vegetarians and omnivores.[62] This is possibly related to a correlation seen in survey research, where vegetarianism and veganism appear to be more commonly affected by some mental disorders like anxiety and depression.[63]
While seasoned lifters may choose to do different exercises every day during a week-long period (and repeat the same moves the following week), there's no need to follow this type of program when you're just getting comfortable, says Davis. "Stick to the same basic moves two to three times a week to build a basic level of fitness and strength," says Davis. "Why complicate things if you don’t have to? Great results can be made by repeating the same workout but increasing weights as you become stronger." Switching things up can help you avoid a training plateau, explains Davis, but so can increasing weights while doing the same exercises.

Although creatine can be bought commercially as a standalone product it is often found in combination with other nutrients. A prime example is the combination of creatine with carbohydrate or protein and carbohydrate for augmenting creatine muscle retention [5] mediated through an insulin response from the pancreas [69]. Steenge et al [70] found that body creatine retention of 5 g CM was increased by 25% with the addition of 50 g of protein and 47 g of carbohydrate or 96 g carbohydrate when compared to a placebo treatment of 5 g carbohydrate. The addition of 10g of creatine to 75 g of dextrose, 2 g of taurine, vitamins and minerals, induced a change in cellular osmolarity which in addition to the expected increase in body mass, seems to produce an up regulation of large scale gene expression (mRNA content of genes and protein content of kinases involved in osmosensing and signal transduction, cytoskeleton remodelling, protein and glycogen synthesis regulation, satellite cell proliferation and differentiation, DNA replication and repair, RNA transcription control, and cell survival) [25]. Similar findings have also been reported for creatine monohydrate supplementation alone when combined with resistance training [71].

Change things up. After six or more weeks of consistent strength training, which is about the amount of time it takes to start seeing improvement in your body, you can change your routine to make it more difficult. Lifting the same weights for the same exercises every week will keep your body in the same place. You can modify weights or repetitions, choose different exercises, or change the order in which you do them. You only have to make one change at a time to make a difference, although more is often better. 
Children: Creatine is POSSIBLY SAFE in children when taken by mouth appropriately. Creatine 3-5 grams daily for 2-6 months has been taken safely in children 5-18 years of age. Creatine 2 grams daily for 6 months has been taken safely in children 2-5 years of age. Additionally, creatine 0.1-0.4 grams/kg daily for up to 6 months has been taken safely in both infants and children.
Present in much greater levels in men than women, testosterone initiates the development of the male internal and external reproductive organs during foetal development and is essential for the production of sperm in adult life. This hormone also signals the body to make new blood cells, ensures that muscles and bones stay strong during and after puberty and enhances libido both in men and women. Testosterone is linked to many of the changes seen in boys during puberty (including an increase in height, body and pubic hair growth, enlargement of the penis, testes and prostate gland, and changes in sexual and aggressive behaviour). It also regulates the secretion of luteinising hormone and follicle stimulating hormone. To effect these changes, testosterone is often converted into another androgen called dihydrotestosterone. 
The important role of nutrition in building muscle and losing fat means bodybuilders may consume a wide variety of dietary supplements.[41] Various products are used in an attempt to augment muscle size, increase the rate of fat loss, improve joint health, increase natural testosterone production, enhance training performance and prevent potential nutrient deficiencies.
There is a great amount of research published on creatine supplementation; protocols of administration, forms of creatine, as well as potential side effects. Despite this, the mechanisms by which creatine acts in the human body to improve physical and cognitive performance are still not clear. The main objectives of this review are to analyze the more recent findings on the effects and mechanisms of creatine supplementation in sports and health. As a secondary purpose, we will analyze the most recommended protocols of ingestion and its potential side effects.
If you reflect on the effects of creatine supplementation within cells, you can probably come up with numerous conditions in which creatine may help people prevent or overcome morbidity. Sometimes, for example, energy supply to tissues is temporarily compromised, as in the case of impaired blood flow to the brain (cerebrovascular disease) or heart (myocardial ischemia). Sure enough, there’s preliminary evidence that creatine may help in these pathologies.
The gluteus medius muscle originates on the outer surface of the ilium between the iliac crest and the posterior gluteal line above, and the anterior gluteal line below; the gluteus medius also originates from the gluteal aponeurosis that covers its outer surface. The fibers of the muscle converge into a strong flattened tendon that inserts on the lateral surface of the greater trochanter. More specifically, the muscle's tendon inserts into an oblique ridge that runs downward and forward on the lateral surface of the greater trochanter.

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]


Brain injury. Early research shows that taking creatine by mouth daily for 7 days increases the ability to exercise by increasing lung function in people with a spinal cord injury. However, other research shows that creatine does not improve wrist muscle or hand function. Early research also shows that taking creatine by mouth daily for 6 months reduces amnesia following a traumatic brain injury in children.
When females have a higher baseline level of testosterone, they have higher increases in sexual arousal levels but smaller increases in testosterone, indicating a ceiling effect on testosterone levels in females. Sexual thoughts also change the level of testosterone but not level of cortisol in the female body, and hormonal contraceptives may affect the variation in testosterone response to sexual thoughts.[51]
Trouble walking, running or doing other activities — Any physical movement that involves stability, flexibility and strength in the legs and hips can be compromised. For example, yoga, dancing, horseback riding, cycling, hiking, burst training, sprinting, plyometrics or tabata workouts, and other activities will be more difficult with underdeveloped glutes. 
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