Low testosterone levels can cause mood disturbances, increased body fat, loss of muscle tone, inadequate erections and poor sexual performance, osteoporosis, difficulty with concentration, memory loss and sleep difficulties. Current research suggests that this effect occurs in only a minority (about 2%) of ageing men. However, there is a lot of research currently in progress to find out more about the effects of testosterone in older men and also whether the use of testosterone replacement therapy would have any benefits.
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].

A: Let your symptoms be your guide. A slight sore throat or runny nose may require you to back off for a day or two but don’t confine yourself to your bed and assume the worst. However, you must also remember that prolonged, intense exercise can decrease immune function and make you more susceptible to bacterial and viral based sickness so it's equally as important to listen to your body and respond accordingly.


A dose of 5g daily has strong evidence supporting it not causing any adverse side effects[605] and 10g has been used daily for 310 days in older adults (aged 57+/-11.1) with no significant differences from placebo.[519] Such a dose has also been demonstrated for long-term safety for people with Parkinson’s disease,[606] and at least one small retrospective study in athletes (surverying people taking creatine for up to or over a year) failed to find any significant differences in a battery of serum health parameters.[502] Other studies measuring serum parameters have also failed to find abnormalities outside the normal range.[607]
During the second trimester, androgen level is associated with sex formation.[13] This period affects the femininization or masculinization of the fetus and can be a better predictor of feminine or masculine behaviours such as sex typed behaviour than an adult's own levels. A mother's testosterone level during pregnancy is correlated with her daughter's sex-typical behavior as an adult, and the correlation is even stronger than with the daughter's own adult testosterone level.[14]

In otherwise sedentary and healthy men given a loading phase of creatine followed by 11 weeks of maintenance, the glucose response to an oral glucose tolerance test is reduced by 11-22% (measurements at 4-12 weeks with no time dependence noted) which was not associated with changes in insulin levels or sensitivity.[350] Elsewhere, a study in vegetarians (5g daily for 42 days) failed to find a reduction in postprandial blood glucose.[351]
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.
In addition to the basic principles of strength training, a further consideration added by weight training is the equipment used. Types of equipment include barbells, dumbbells, pulleys and stacks in the form of weight machines, and the body's own weight in the case of chin-ups and push-ups. Different types of weights will give different types of resistance, and often the same absolute weight can have different relative weights depending on the type of equipment used. For example, lifting 10 kilograms using a dumbbell sometimes requires more force than moving 10 kilograms on a weight stack if certain pulley arrangements are used. In other cases, the weight stack may require more force than the equivalent dumbbell weight due to additional torque or resistance in the machine. Additionally, although they may display the same weight stack, different machines may be heavier or lighter depending on the number of pulleys and their arrangements.
Researchers found that 5g of creatine four times daily for a week (loading) before sleep deprivation for 12-36 hours was able to preserve cognition during complex tasks of executive function at 36 hours only, without significant influence on immediate recall or mood.[279] A similar protocol replicated the failure to improve memory and attention, but noted less reports of fatigue (24 hours) and less decline of vigor (24 hours) although other mood parameters were not measured.[276]
Creatine monohydrate is the most common form of creatine, and if not otherwise mentioned is the default form of creatine used in most studies on creatine.[64] It has fairly decent intestinal absorption[65][12] (covered more in depth in the pharmacology section) and is the standard form or “reference” form of creatine, which all other variants are pitted against.
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.
In the 1970s, bodybuilding had major publicity thanks to the appearance of Arnold Schwarzenegger, Franco Columbu, Lou Ferrigno, and others in the 1977 docudrama Pumping Iron. By this time, the IFBB dominated the competitive bodybuilding landscape and the Amateur Athletic Union (AAU) took a back seat. The National Physique Committee (NPC) was formed in 1981 by Jim Manion,[7] who had just stepped down as chairman of the AAU Physique Committee. The NPC has gone on to become the most successful bodybuilding organization in America and is the amateur division of the IFBB. The late 1980s and early 1990s saw the decline of AAU-sponsored bodybuilding contests. In 1999, the AAU voted to discontinue its bodybuilding events.
Testosterone is significantly correlated with aggression and competitive behaviour and is directly facilitated by the latter. There are two theories on the role of testosterone in aggression and competition.[81] The first one is the challenge hypothesis which states that testosterone would increase during puberty thus facilitating reproductive and competitive behaviour which would include aggression.[81] Thus it is the challenge of competition among males of the species that facilitates aggression and violence.[81] Studies conducted have found direct correlation between testosterone and dominance especially among the most violent criminals in prison who had the highest testosterone levels.[81] The same research also found fathers (those outside competitive environments) had the lowest testosterone levels compared to other males.[81]

If you're serious about putting on some muscle, then the most efficient way to do it is with three intense resistance training sessions and two lighter intensity workouts per week. “You need to have consistency in a workout program, hitting at least each muscle group two times a week to build muscle,” explains Lovitt. If you’re looking to switch up exercises, Olson suggests swaps such as sumo squats instead of traditional squats; step-ups on a bench instead of lunges; and then rotating back to the former. “These types of variation can be very effective in developing muscles, but the weights must still be fairly heavy that you’re using,” she says.


In complex training, weight training is typically combined with plyometric exercises in an alternating sequence. Ideally, the weight lifting exercise and the plyometric exercise should move through similar ranges of movement i.e. a back squat at 85-95% 1RM followed by a vertical jump. An advantage of this form of training is that it allows the intense activation of the nervous system and increased muscle fibre recruitment from the weight lifting exercise to be utilized in the subsequent plyometric exercise; thereby improving the power with which it can be performed. Over a period of training, this may enhance the athlete's ability to apply power.[39] The plyometric exercise may be replaced with a sports specific action. The intention being to utilize the neural and muscular activation from the heavy lift in the sports specific action, in order to be able to perform it more powerfully. Over a period of training this may enhance the athlete's ability to perform that sports specific action more powerfully, without a precursory heavy lift being required.

Testosterone is most commonly associated with sex drive in men. It also affects mental health, bone and muscle mass, fat storage, and red blood cell production. Abnormally low or high levels can affect a man’s mental and physical health. Your doctor can check your testosterone levels with a simple blood test. Testosterone therapy is available to treat men with low levels of testosterone. If you have low T, ask your doctor if this type of therapy might benefit you.

Phosphocreatine is known to be a major source of energy for cardiac tissue alongside fatty acids, which are dominant under periods of normoxia (normal oxygen) while phosphocreatine becomes more important in periods of hypoxic stress.[281][282][283] The entire CK system plays a role in the recovery of the heart following ischemic/hypoxic stress, since blocking CK activity impairs recovery[284][285] and overexpressing CK activity promotes it.[286] This is due to the heart tissue needing high energy phosphate groups at this time, and the ischemic stress reduces CK activity and the ability of CK to donate these groups.[287][288]

Falling in love decreases men's testosterone levels while increasing women's testosterone levels. There has been speculation that these changes in testosterone result in the temporary reduction of differences in behavior between the sexes.[53] However, it is suggested that after the "honeymoon phase" ends—about four years into a relationship—this change in testosterone levels is no longer apparent.[53] Men who produce less testosterone are more likely to be in a relationship[54] or married,[55] and men who produce more testosterone are more likely to divorce;[55] however, causality cannot be determined in this correlation. Marriage or commitment could cause a decrease in testosterone levels.[56] Single men who have not had relationship experience have lower testosterone levels than single men with experience. It is suggested that these single men with prior experience are in a more competitive state than their non-experienced counterparts.[57] Married men who engage in bond-maintenance activities such as spending the day with their spouse/and or child have no different testosterone levels compared to times when they do not engage in such activities. Collectively, these results suggest that the presence of competitive activities rather than bond-maintenance activities are more relevant to changes in testosterone levels.[58]


Because I don’t want you to have to waste all the years and money that I did (not to mention the surgeon’s bills), I came up with a method of training and eating specifically for skinny-fat, injury-prone hard-gainers: guys who historically can’t gain muscle doing the workouts they find in magazines or on blogs. It’s also perfect for all guys over age 35 who need to be smarter with their training as they age.
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]
Perform bent over rows to work your back. Stand with your feet shoulder-width apart, about 6 to 10 inches (15–25 cm) behind the barbell or two dumbbells. Bend slightly at the knees but keep your shins vertical. Bend forward at the waist with your spine and head straight. Lift the weight with an overhand grip up to your lower chest or upper abdomen. Lower slowly until your arms are nearly extended, without touching the ground. 3 x 8.[5]
Injections of creatine are known to be neuroprotective against low oxygen levels (hypoxia) even to neonatal rats.[532] This is thought to be associated with the increased collective pool of phosphocreatine and creatine.[236] Since oral ingestion of creatine by the mother increases brain concentrations of creatine by 3.6% in the fetus prior to birth,[531] it is thought to be protective in the fetuses subject to hypoxic (low oxygen) stressors, such as a caesarean section.
Every 4-8 weeks, vary your routine. As your body adapts to stress, you'll hit a plateau where the benefits of weight training will begin to diminish. The only way to prevent this from happening is to change things up, such as by increasing weight and changing exercises. Try a week of really piling the weights on, and do six to eight reps per set at the maximum weight you can manage with proper form. The more lifting experience you have, the more often you should vary your routine.
The majority of studies have used nothing but a loading period and the duration, overall, was about a week. This is partially because one study that noted benefit with a loading period failed to note benefit with prolonged supplementation.[156] Lowballing supplementation at 2g a day in high active swimmers does not appear to be sufficient to alter any function in skeletal muscle.[383]

I can’t predict what sort of results you’ll see in that first year, but it can be pretty epic if you attack it right! Muscle growth might happen slower than you want, but I expect something different will happen along the way – you’ll fall in love with this idea of building STRENGTH! In fact, getting hooked on progress, and strength training is one of the best things you can do for yourself. 

Less muscle breakdown can also help to reduce post-workout muscle soreness levels. During workouts, the body creates lactic acid as it works to generate extra energy. The buildup of lactic acid can cause muscle fatigue, swelling, and tenderness. Improving the ability of the body to recover can help to more effectively clear out lactic acid, reducing inflammation and soreness.
There are several ways to enhance the quality of a workout, and some changes can even be made during each rep. “Constant tension should be applied to the last five reps of every working set, meaning, do the first 5-6 reps normal tempo, and the last few reps should be held for at least two seconds at the peak of the contraction,” says Heath. “This allows your muscles to have more time under tension and you work different muscle fibers.” Hold the weight at the top for a maximum pump.

You see, there is only so much muscle that the human body is capable of building in a given period of time. So, if you supply your body with MORE calories than it’s actually capable of putting towards the process of building new muscle… it’s not going to magically lead to additional muscle being built. It’s just going to lead to additional fat being gained.


Creatine is classified as a "dietary supplement" under the 1994 Dietary Supplement Health and Education Act and is available without a prescription. Creatine is not subjected to FDA testing, and the purity and hygienic condition of commercial creatine products may be questionable [21]. A 1998 FDA report lists 32 adverse creatine-associated events that had been reported to FDA. These include seizure, vomiting, diarrhea, anxiety, myopathy, cardiac arrhythmia, deep vein thromboses and death. However, there is no certainty that a reported adverse event can be attributed to a particular product [22]. A recent survey of 28 male baseball players and 24 male football players, ages 18 to 23, found that 16 (31%) experienced diarrhea, 13 (25%) experienced muscle cramps, 7 (13%) reported unwanted weight gain, 7 (13%) reported dehydration, and 12 reported various other adverse effects [23].
If you'’re looking to add muscle mass to your frame, hitting the weights hard is a given. Quality time in the gym begins a cascade of changes that will stimulate your muscles to grow bigger in response to the challenges you throw their way. It'’s tempting to think that'’s all it takes to add muscle to your body. After all, you can actually feel your biceps growing after an intense set of curls.
In males, testosterone is required for the development of male sex organs such as increased penis and testes size. The hormone also promotes the development of sexual male characteristics during puberty such as voice deepening and the growth of armpit, chest and pubic hair. Testosterone plays an important role in maintaining sex drive, sperm production, muscle strength and bone mass. A healthy level of testosterone is also protective against bone disorders such as osteoporosis.
A: Eat more frequently, drink less liquids while eating (they compete for stomach volume along with food), eat from larger plates and bowls, add lime or lemon juice to your water with meals (can help to increase production of hydrochloric acid that breaks down food), and consume more liquid calories (especially around the workout if appetite is suffering the rest of the day).
Studies of so-called "smart drugs" have also been taken out of context. Some "smart" nutrients, available over the counter, are marketed as a way to "increase mental focus and concentration during training." The problem is that the studies they're based upon involved either animals or people with brain pathology. In normal people the effects of smart drugs remain unproven, except anecdotally.
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.
Synthesis primarily takes place in the kidney and liver, with creatine then being transported to the muscles via the blood. The majority of the human body's total creatine and phosphocreatine stores is located in skeletal muscle, while the remainder is distributed in the blood, brain, and other tissues.[17][18][20] Typically, creatine is produced endogenously at an estimated rate of about 8.3 mmol or 1 gram per day in young adults.[16][17] Creatine is also obtained through the diet at a rate of about 1 gram per day from an omnivorous diet.[17][18] Some small studies suggest that total muscle creatine is significantly lower in vegetarians than non-vegetarians, as expected since foods of animal origin are the primary source of creatine. However, subjects happened to show the same levels after using supplements.[21]
The Organon group in the Netherlands were the first to isolate the hormone, identified in a May 1935 paper "On Crystalline Male Hormone from Testicles (Testosterone)".[185] They named the hormone testosterone, from the stems of testicle and sterol, and the suffix of ketone. The structure was worked out by Schering's Adolf Butenandt, at the Chemisches Institut of Technical University in Gdańsk.[186][187]
A previous meta-analysis [28] reported an overall creatine supplementation effect size (ES) of 0.24 ± 0.02 for activities lasting ≤30 s. (primarily using the ATP- phosphocreatine energy system). For this short high-intensity exercise, creatine supplementation resulted in a 7.5 ± 0.7% increase from base line which was greater than the 4.3 ± 0.6% improvement observed for placebo groups. When looking at the individual selected measures for anaerobic performance the greatest effect of creatine supplementation was observed on the number of repetitions which showed an ES of 0.64 ± 0.18. Furthermore, an increase from base line of 45.4 ± 7.2% compared to 22.9 ± 7.3% for the placebo group was observed. The second greatest ES was on the weight lifted at 0.51 ± 0.16 with an increase from base line of 13.4 ± 2.7% for the placebo group and 24.7 ± 3.9% for the creatine group. Other measures improved by creatine with a mean ES greater than 0 were for the amount of work accomplished, weight lifted, time, force production, cycle ergometer revolutions/min and power. The possible effect of creatine supplementation on multiple high intensity short duration bouts (<30 s) have shown an ES not statistically significant from 0. This would indicate that creatine supplementation might be useful to attenuate fatigue symptoms over multiple bouts of high-intensity, short duration exercise. The ES of creatine on anaerobic endurance exercise (>30 – 150s), primarily using the anaerobic glycolysis energy system, was 0.19 ± 0.05 with an improvement from baseline of 4.9 ± 1.5 % for creatine and -2.0 ± 0.6% for the placebo. The specific aspects of anaerobic endurance performance improved by creatine supplementation were work and power, both of which had a mean ES greater than 0. From the findings of this previous meta-analysis [28] it would appear that creatine supplementation has the most pronounced effect on short duration (<30s) high intensity intermittent exercises.
Focus on form. Good form means you can reap all of the benefits of your workout and avoid injuries at the same time. To maintain proper form, pay attention to your posture (stand tall with chest lifted and abs held tight), move slowly (this ensures you're relying on muscles, not momentum, to do the lifting), and remember to breathe. Many people hold their breath while exerting, but exhaling during the hardest part of the exercise helps fuel the movement.
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