Muscular strength refers to the amount of force a muscle is capable of exerting. The most common way to assess strength in a resistance exercise program is to measure the maximum amount of weight you can lift one time. This value is known as the one repetition maximum and is abbreviated 1RM. Muscular endurance is defined as a muscle’s ability to exert force repeatedly without fatiguing. The more repetitions of a certain resistance exercise you can perform successfully (e.g., a bench press of one half your body weight), the greater your muscular endurance.

There are three key principles to understand if you intend to maximize muscular strength and endurance benefits from your resistance exercise program. Unless you follow these principles, you are likely to be disappointed in the results of your program.

The Tension Principle

The key to developing strength is to create tension within a muscle. The more tension you can create in a muscle, the greater your strength gain will be. The most common recreational way to create tension in a muscle is by lifting weights. While weight lifting is one method of producing tension in a muscle, any activity that creates muscle tension – for example, riding a bike up a hill – will result in greater strength. It really does not matter what type of equipment you choose to develop tension in your muscles; what matters is that you use the equipment in a way that produces the desired strength and endurance.

The Overload Principle

The overload principle is the most important of the three key principles for improving muscular strength. Everyone begins a resistance training program with an initial level of strength. To increase that level of strength, you must regularly create a degree of tension in your muscles that is greater than they are accustomed to. This overloading of your muscles will cause your muscles to adapt to the new level of overload. As your muscles respond to a regular program of overloading by getting larger (hypertrophy), they become capable of generating more tension.

Some women avoid resistance exercise because they fear that they’ll develop large “bulky” muscles, while others are frustrated because their weight-lifting efforts in the gym don’t produce the results they see in their male friends. The main reason for this difference is the hormone testosterone. Before puberty, testosterone levels in blood are similar for both boys and girls. During adolescence, testosterone in men increases about tenfold to its adult level; testosterone in women remains at prepubertal levels throughout adulthood. Women’s muscles will achieve hypertrophy from regular exercise but typically not to the same degree as in adult males. Using the exceptional muscular development of elite female bodybuilders as our example, we know that considerable muscle hypertrophy is possible among women. Most likely, many of these women used anabolic steroids to increase their muscle mass and development. The difference in maximum attainable hypertrophy between men and women (without the aid of anabolic steroids) is not currently known.

The Specificity of Training Principle

This principle refers to the manner in which a specific body system responds to the physiological demands placed upon it. According to the specificity principle, the effects of resistance exercise training are specific to the area of the body being exercised. If the overload you impose is designed to improve strength in the muscles of your chest and back, the response to that demand (overload) will be improved strength in those muscles only.

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During the past century, there have been marked changes in the disease profile in the developed and developing countries. The noncommunicable diseases like diabetes, hypertension and heart disease have replaced the infectious diseases and are posing a major cause of morbidity and mortality.

The WHO study linked data from WHO developed global database on diabetes with UN demographic projections in order to estimate the number of people with diabetes in all countries of the world at 3 points in time – 1995, 1000 and 2025.

Introduction: According to the study by WHO, between 1995 and 2025, the number of people with diabetes in INDIA is projected to rise from 19 to 57 million, i,e. an increase of 195%, indicating global burden of diabetes.

In the developed countries the 1995 figure of 51 million diabetics is expected to rise to 72 million by 2025 (42% increase). By 2025, the developing countries v/ill be home to 76% of all persons with diabetes as compared with 62% in 1995.

Worldwise, 122% rise is projected from the total of 135 to 300 million. That is more than 2 fold global increase will occur because of population gain and growth, as well as from obesity, unhealthy diets and sedentary life style. These later factors are closely associated with urbanization and industrialization.

The 3 top countries with diabetes in 2025 are India (57 million ), followed by China (38 million) and the USA (22 millions).

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Prevalence of type 2 diabetes increases with aging. Harris found in 1990 that by the age of 65 years, 18% of the U.S. population has been diagnosed with diabetes. Some suggest that the increased prevalence of type 2 diabetes with aging is due to “aging genes.” In fact, 91 % of cases of type 2 diabetes are associated with environmental factors, and most can be prevented by a physically active lifestyle.

Seals et al studied glucose tolerance in athletes and sedentary men. Master’s athletes (60 years old) who averaged 8 miles/day of running did not have the age-associated higher rise in postprandial blood glucose and insulin. Moreover, the post-meal rise in blood insulin was half that occurring in the young, untrained men. Young, untrained subjects were able to maintain normal blood glucose levels in an oral glucose tolerance test by the pancreas compensating with a higher secretion of insulin. Increased postprandial rises in blood glucose and insulin in the “old, untrained, and lean” are called insulin resistance or the “pre-diabetic” state.

Thus, the insulin sensitivity of old Master’s athletes was higher than untrained young and old subjects. Old Master’s athletes had no insulin resistance, i.e., their physical activity levels were sufficient to totally prevent the so-called aging-associated increase in type 2 diabetes. The conclusion may be drawn that physical activity can delay/prevent the “age-related” onset of type 2 diabetes!

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