Sports Fitness Training

Static Exercise

Isometric contractions are usually held for 6 to 10 seconds and require a minimum exertion of two thirds maximum force. Maximum exertions produce greater results than sub-maximum efforts. A total contraction time of 30 seconds of applied force is desirable. This can be achieved by two or three confections of long duration or more contractions of shorter duration for each muscle exercised.

Isometric exercises are effective for developing strength, but this approach has some important limiations. The most serious of these is a higher than expected rise in exercise arterial blood pressure and an increased workload on the heart throughout the entire contraction. All-out straining isometric contractions should not be performed by individuals with heart and vascular disease. A second limitation is that strength developed isometrically is joint­angle specific. Maximum strength development occurs at the angle of contraction, with a training carryover of approximately 20 degrees in either direction from that angle. To develop strength throughout the muscle’s range of motion, you must perform isometric contractions at several different points in the range of motion.

Because muscles cannot overcome the resistance in isometric training, measuring improvement is difficult, constituting another limitation of this system. Improvements in strength can be measured if exercisers have access to specialized equipment, such as dynamometers and tensiometers, that record the amount of force applied. Motivation for exercise is difficult to sustain without feedback.

Research indicates that isometric exercise systems are as effective as dynamic exercise systems for developing strength. The question is not which system is better but which system best satisfies the intended use for the newly acquired strength. The transferability of strength to occupational and leisure pursuits is very relevant.

Strength developed in the muscles is highly specific to the manner in which the muscles are trained .muscles trained isometrically perform best when stressed isometrically; muscles trained dynamically perform best when stressed dynamically. There is some transfer of isometric training to everyday life. Carrying groceries, a baby, or any object in a fixed position or pushing and pulling objects requires isometric strength, but most movements are dynamic, md transfer is more widely applicable from dynamic systems of training.

Dynamic Exercise

Dynamic exercises include isotonic (equal tension), variable resistance, free weights, and isokinetic (equal speed).

Isotonic Training

Isotonic exercise training systems use both concentric and eccentric contractions as the exercising muscle shortens and lengthens about a joint. Both types of contractions contribute to the development of strength.

Variable Resistance Training

Variable resistance exercise equipment was developed in response to isotonic exercises not maximally stressing muscles throughout their full range of motion. The maximum weight lifted isotonically is limited to the weakest point in the musculoskeletal leverage system. The weight appears lighter at some points in the joint movement and heavier at others. In reality, the weight itself is constant and the human bony leverage system changes.

Free-Weight Training

Isotonic training with free weights (dumbbells and barbells) continues to be an appropriate method for strength development. Free-weight training provides many advantages. For athletes, it yields some flexibility in strength development because the movements are not confined to a track. Exercises can be selected or improvised to simulate the movements required by specific sports, allowing the development of the muscles that will be used in competition. Concurrently, ancillary musculature that plays a supporting or stabilizing role for the major muscles is also stimulated and developed.

Circuit Resistance Training

Circuit resistance training (CRT) is very effective for individuals who wish to develop several fitness dimensions simultaneously. Muscular strength and endurance, changes in body composition, and improvement in cardiorespiratory endurance can be attained together.