JAK2 (Janus-Activating Kinase 2) is a novel protein that has been shown to suppress the activity of the creatine transporter CrT in vitro. The effects of JAK2 on CrT are not well-understood in vivo, however. Given that growth hormone activates both c-src (increases CrT activity) and JAK2- which has been found to decrease CrT activity, it is plausible that JAK2 may function as a negative-feedback regulator of creatine uptake. Future research is needed to better understand the role of JAK2 on CrT activity in vivo.
Taking creatine supplements may increase the amount of creatine in the muscles. Muscles may be able to generate more energy or generate energy at a faster rate. Some people think that taking creatine supplements along with training will improve performance by providing quick bursts of intense energy for activities such as sprinting and weightlifting.
Stronger muscles improve performance in a variety of sports. Sport-specific training routines are used by many competitors. These often specify that the speed of muscle contraction during weight training should be the same as that of the particular sport. Sport-specific training routines also often include variations to both free weight and machine movements that may not be common for traditional weightlifting.
Creatine is a molecule produced in the body. It stores high-energy phosphate groups in the form of phosphocreatine. Phosphocreatine releases energy to aid cellular function during stress. This effect causes strength increases after creatine supplementation, and can also benefit the brain, bones, muscles, and liver. Most of the benefits of creatine are a result of this mechanism.
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.
Activation of NMDA receptors is known to stimulate Na+,K+-ATPase activity secondary to calcineurin, which which has been confirmed with creatine in hippocampal cells (0.1-1mM trended, but 10mM was significant). This is blocked by NMDA antagonists. This increase in Na+,K+-ATPase activity is also attenauted with activation of either PKC or PKA, which are antagonistic with calcineurin.
If you have low testosterone, your functional medicine or anti-aging physician will help you diagnose it. There are several different hormones your physician should measure, but the most important two are your free testosterone and estrogen levels, because converting too much testosterone to estrogen is a problem that’s different from not making enough testosterone in the first place. In my case, I wasn’t making very much testosterone, and what I was making my body converted to estrogen way too effectively.
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, this study failed to find an influence on activities of daily living or lung function. Elsewhere in children not on corticosteroids with DMD, supplementation of 5g creatine for eight weeks was confirmed to increase muscular phosphocreatine content 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%).
"Start with two days for two to three weeks, then add a third day," says Davis*.*"Ideally, you should strength train three to five days per week, but work your way up—starting off at five days a week might shock your body." Here's a comprehensive three-day-per-week plan to get you started. Aim to complete 20-minute sessions, then gradually add on time in ten-minute increments until you're working for 45 to 60 minutes, suggests Davis.
The major controversies regarding creatine are its side effects and the best form to use. Nearly all side effects attributed to creatine, such as muscle cramps, kidney disease and gastrointestinal disturbances, haven't proved significant under controlled scientific scrutiny. Although various claims are made for a variety of creatine supplements, creatine monohydrate, which is 99 percent absorbed, is the best form to use.
One case study on a subject with a methylentetrahydrofolate reductase (MTHFR) 677TT homozygote, a relatively common genetic mutation known as “mild MTHFR deficiency,” which causes mild homocysteinemia, has seen benefits due to creatine supplementation where homocysteine was approximately halved (49% reduction) while CT heterozygotes and CC homozygotes (n=9) were unaffected. Additionally, one rat study suggested a possible role for creatine in reducing homocysteine levels in a model of high uric acid levels (model for end stage renal disease) but this was not replicated when investigated in humans.
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.