Originally Posted by chic_magnet

well... most of it is false yea.... go to any good gym they'd tell you all this is false....

and hmm the first one is true actually... research shows that if you do 15 repetitions with 10 pounds and 5 repetitions with 25 pounds , your muscles are still doing the same amount of work, and you could actually build the same kinda body a big bulky body builder would build( in terms of muscle definition and not strength)... ..this is wat i read in TOI... i think..

Therapeutic exercises aimed at achieving and maintaining physical fitness fall into 3 major categories, each with a specific purpose.

Endurance training that requires isotonic (dynamic) exercise technique

Muscle strength training that requires isometric (static) exercise technique

Techniques to maintain flexibility

Isotonic (dynamic) muscle contraction

Isotonic exercise also is called active range of motion (AROM) exercise. The muscle shortens during isotonic exercise. Isotonic muscle contraction causes a rise in the heart rate and a marked increase in stroke volume that results in an increase in cardiac output and a net decrease in peripheral resistance (due to vasodilatation of contracted muscles). A moderate rise in systolic blood pressure occurs, but the diastolic pressure usually remains unchanged.

Eccentric isotonic training does not produce an increase in muscle strength, but concentric isotonic training does. However, isometric exercise is the most effective exercise for increasing the muscle contractile force. The isotonic exercise is suitable for endurance training but not for training of muscle strength. In endurance training, large muscle groups are engaged in a continuous aerobic activity.

Application to healthy individuals

Exercises such as walking, running, jogging, dancing, stair climbing, cycling, swimming, rowing, skating, and cross-country skiing are recommended for performance at an intensity of 60-90% of maximum heart rate or to a heart rate at 50-85% of maximum O 2 uptake.

If the maximum attained heart rate (HR max) has not been estimated, the age adjusted maximum heart rate (AAMHR) can be calculated from the following formula:

HR max = 220 - Age

Note that this formula can be inaccurate in the ill or elderly patient.

The endurance training should be structured to include 5 minutes of warm-up activity, 30 minutes of training, and a 5-minute period for cool down.

The minimum duration of endurance training for healthy men and women recommended by the American College of Sports Medicine (ACSM) is 20-60 minutes 3-5 days a week.

Application to patients

For at risk patients, especially those with cardiac or respiratory disease, a less intense training regimen must be used, with the training heart rate not exceeding that attained at 50-60% of maximum O 2 uptake.

In the absence of data regarding the maximum attained heart rate measurements, it is prudent not to allow the patient to exceed the heart rate of 130 beats per minute (bpm). In elderly patients and patients at risk, the intensity, frequency, and duration of therapeutic exercise should be established for each patient individually through prior medical evaluation (see Medical evaluation ).

Isometric (static) muscle training

Isometric (static) muscle training also is referred to as resistive strength training (RST) or resistive exercise because resistance is applied to the contracting muscle, preventing it from shortening. Daily application of this technique for 6 seconds only, using two thirds of maximal contractile force, results in an optimal increase of muscle strength. Progressive increase in the resistance, frequency of training, and duration of resistance enhances the effect.

Isometric training requires great caution because it causes a rise in heart rate (due to decreased vagal tone and increased discharge of cardiac sympathetic nerves). Within a few seconds of the start of isometric exercise, both the systolic and diastolic blood pressures rise.

The stroke volume changes relatively little, and the blood flow to the steadily contracting muscle is reduced as a result of compression of its blood vessels. The heart rate rises even when contraction is prevented by infusion of neuromuscular blocking drug locally or at the mere thought of carrying out the muscle contraction, suggesting the action of a psychic stimulus.

Application to healthy individuals

For healthy men and women, the ASCM currently recommends "at least one set of 8-12 repetitions of 8-10 RST exercises that condition the major muscle groups at least twice a week."

Application to patients

As with the isotonic dynamic exercise, the intensity, frequency, and duration of isometric static exercise must be established for each patient individually, according to the results of the prior medical evaluation (see Medical evaluation ).

Since this form of training requires great caution, it may be prudent, especially in patients with cardiovascular diseases, not to extend the duration of an isometric contraction beyond 6 seconds. The pause between 2 isometric contractions should equal or exceed 20 seconds to allow time for the reconstitution of ATP (see Biochemical Aspects of Physical Fitness ).