Muscular fitness can be defined as the strength, muscular endurance, and flexibility that are needed to carry out daily tasks and avoid injury.

How you attain a certain degree of muscular development is dependent upon a number of factors. One thing is clear, however: a program that incorporates weight lifting along with weight-bearing aerobic activity is essential.

Creatine and all the supplements in the world will make very little difference in terms of building muscle if resistance training is not included.

Even if you decide you don't need muscle building for injury prevention, performance, or even bodybuilding, you should still consider a minimum program throughout your life. A minimum program of muscle maintenance will go a long way in the prevention of lower back and posture-related problems.

In addition, research shows that a muscle-building program can help avoid the progressive decrease in the density of bones commonly known as osteoporosis.

Aging and muscle loss

Muscle loss can result from the combined effects of many age-related changes. Insulin-like growth factor-1 (IGF-1) is a growth hormone responsible for cell growth, maintenance, and repair in a variety of different tissues including muscle, GI (gastrointestinal) tract, and skin.

Reduced IGF-1 signaling is implicated in muscle atrophy resulting from reduced growth hormone and treatment with drugs such as corticosteroids, dexamethasone, and cyclosporin.

Under-nutrition resulting in a lack of vitamin D and physical inactivity are also factors in age-related muscle loss. In addition, elevated levels of inflammatory cytokines like TNF-alpha and IL-6 can cause muscle wasting (cachexia), although this is usually associated with disease. TNF-alpha may also act (at least in part) by inhibiting IGF-I signaling.

In aging males, muscle loss can also be the result of the down-regulation of the hypothalamic-anterior pituitary-testicular axis.

As aging progresses, there are relative increases in body fat and decreases in muscle mass. The increase in adipose tissue is connected to an increase in the enzyme aromatize which converts testosterone to estradiol and leads to diminished testosterone levels and the deposition of visceral fat.

As the total body fat mass increases, hormone resistance for insulin ultimately develops. For women, it is now well established that the decline in testosterone and the adrenal preandrogens also plays a significant role in affecting perimenopausal and menopausal symptomatology and quality of life. Loss of circulating levels of androgens affects libido, vasomotor symptoms, mood and well being, bone structure, and muscle mass.

Losing fat while building muscle

Excess body fat accumulates via two distinct mechanisms. People either form more adipocytes (fat cells) and/or existing adipocytes absorb too much fat-glucose and become larger. The effect of too many adipocytes and/or bloated adipocytes is the unsightly and unhealthy amassing of body fat.

Conjugated linoleic acid (CLA) has been shown to decrease the volume of adipocytes and thus reduce body fat. However, many overweight people have too many adipocytes. These people need more than CLA to achieve effective weight control.

In weight-loss studies, CLA consistently shows an ability to reduce body fat while maintaining lean muscle mass.

A study in the August 2001 issue of the International Journal of Obesity and Related Metabolic Disorders concluded that conjugated linoleic acid (CLA) reduces abdominal fat among men classified as abdominally obese.

The study participants taking CLA lost an average of 1.4 cm in waist circumference after only 4 weeks.

This double blind, randomized, placebo-controlled trial observed 25 men with significant abdominal fat for 4 weeks.

Some participants (14) received 4.2 grams of CLA per day, while the others received placebo. At the conclusion of the study, there was a significant decrease of abdominal diameter among the CLA group. None of the study participants changed their eating or exercise habits during the trial period.

Results of this study support data in the December 2000 issue of the Journal of Nutrition. That study concluded that CLA reduced body fat and preserved muscle mass among the 60-person study group. Participants lost an average of 6 lbs while taking CLA.

The key to successful muscle building is to combine resistance training with proper nutrition and effective supplements so that an optimal anabolic environment is created.

So, as it is shown, not only does building muscle make us look better and also feel better, but also and most important building muscle can help and make us live healthier and longer. Everybody should use some form of weight training so they can enjoy some of the benefits of building muscle.