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Overload Principle 9 th Grade Slide 2 Overload Muscular fitness is developed by placing a demand, or overload, on the muscles in a manner to which they are not accustomed.Muscular fitness is developed by placing a demand, or overload, on the muscles in a manner to which they are not accustomed. If the overload is applied progressively and sensibly, the neuromuscular system will positively adapt to the demand.If the overload is applied progressively and sensibly, the neuromuscular system will positively adapt to the demand. Slide 3 General Guidelines The general guideline for change is a proper and specific overload that uses a progressive increase in resistance over time, causes the targeted muscle (s) to fatigue in about 30 to 90 seconds, and challenges all of the major movements (joint actions) to which the muscle (s) contribute. Slide 4 Progressive Increase A progressive increase in resistance provides continued improvements in muscle strength and edurance. A progressive increase in resistance provides continued improvements in muscle strength and edurance. Appropriate intensity (attaining momentary muscular fatigue in about 30 to 90 seconds) is necessary to optimize training results. Appropriate intensity (attaining momentary muscular fatigue in about 30 to 90 seconds) is necessary to optimize training results. Gradual intensity increases will reduce the likelihood of injury. Gradual intensity increases will reduce the likelihood of injury. All of the major movements of the body must be challenged to ensure balanced strength between all of the opposing muscle groups. All of the major movements of the body must be challenged to ensure balanced strength between all of the opposing muscle groups. Slide 5 Aerobic Training In order to maximize overload, aerobic training should follow four rules. Be the correct type Be done at the proper intensity Be of sufficient duration Occur with adequate frequency Slide 6 Research Type: For maximum effectiveness, aerobic exercises need to be rhythmic and continuous and involve the large muscle groups. Intensity: Research shows that optimum exercise intensity for fitness improvement is in the range of about 50% to 85% of maximum oxygen consumption. This corresponds to about 60% to 90% of maximum heart rate. Duration: Aerobic exercise must last for at least 30 minutes per session to lead to substantial fitness improvements over time. Frequency: For cardiovascular training is that the proper type of activity, done at the correct intensity and continued for a sufficient length of time, must be performed at least three days per week. Slide 7 Relationship Between Intensity and Duration If intensity is increased, the duration can be decreased and yet achieve a similar training effect. If intensity is increased, the duration can be decreased and yet achieve a similar training effect. Conversely, if the intensity is decreased, the duration must be increased to achieve the same training. Conversely, if the intensity is decreased, the duration must be increased to achieve the same training. Slide 8 Muscle Fiber Adaptation Hypertrophy: is an increase in the number and size of myofibrils inside muscle fibers. More simply, its an increased amount of actin, myosin and related proteins that are responsible for force generation. When men and women are exposed to the same strength-training program, men will generally hypertrophy to a greater extent than will women. This is primarily because of higher levels of the hormone testosterone in men than in women. Greater muscle size is one reason most men are capable of greater absolute strength than most women. Slide 9 Hypertrophy and Atrophy Muscles Slide 10 Resistance A high-resistance (6 to 10 RM) program will usually lead to significant hypertrophy in most males. Most females, because of naturally low levels of testosterone, will not generate significant hypertrophy even with this type of program. Many women shy away from strength training because of a fear of the body-builder hypertrophy. You can decrease their fears by using lower resistance (12 to 15 RM) programs. Slide 11 Connective Tissue Adaptation 3 basic types Cartilage: which serves as padding between the bones that meet at a joint in the skeleton. Ligaments: which connect bones to bones at a joint. Tendons: which connect skeletal muscles to the bones, transmitting the force of muscle contraction to the bones. Slide 12 Connective Tissue Adaptation continued In response to strength training, the connective tissues associated with muscle become stronger by becoming thicker, and are thus able to withstand the increase strength-trained muscle. Slide 13 Stretching One of the safest overloads for flexibility training is a slow, sustained stretch. Slowly stretch to the point where tension (tightness) is felt in the muscles being stretched. Some research suggest that four sets of 10 to 15 second stretches can lead to significant improvements in flexibility. Slide 14 Decrease Nervous Inhibition Both Psychological and Physiological Psychological: confidence increases, allowing lifts never before thought possible. This is especially true in non- athletes who think themselves weaker than they actually are. Physiological: in the tendons, which connect the muscle to the bones, there is a sensor called a muscle tendon organ or a Golgi tendon organ. Slide 15 Golgi Tendon Organ This tendon organ is a part of the nervous system, a protection against generating too much contractile force. When the muscle tendon organ is stimulated by too much contractile force, its associated muscle will relax to prevent injury to the muscle itself or to its associated connective tissues. Overriding: injury to the connective tissues is when one overrides the threshold protection of the Golgi tendon organs. Example: lifting a car or attempting to lift more weight than you are trained. Slide 16 Types of Strength Overloads Isometric (same length) Isometric: refers to exercises that develop high intensity contractions in the muscle with no change in muscle length. Generally, isometric exercises call for a maximal effort against an immovable object, like a wall or desk. Isometric training clearly increases muscle strength, but only at the joint angle where the contraction occurs. Slide 17 Types of Strength Overloads Isotonic (same tone or tension) Refers to exercises that use a given amount of external resistance which is challenged through the entire range of motion. The tension in the muscle is not constant throughout the range of motion. The actual amount of force generated by a muscle will change throughout the movement because of the biomechanics at the joint or joints involved. Example bicep curl. Slide 18 Types of Strength Overloads Isokinetic (same speed) Refers to a type of resistance exercise that causes the exercising muscles to generate a maximum amount of force throughout the entire range of movement, while keeping the speed of movement constant.Refers to a type of resistance exercise that causes the exercising muscles to generate a maximum amount of force throughout the entire range of movement, while keeping the speed of movement constant. Slide 19 Aerobic vs. Anaerobic Aerobic: with, or in the presence of, oxygen. Anaerobic: without the presence of oxygen; not requiring oxygen. Slide 20 5 Components of Fitness Flexibility Cardiovascular Fitness Muscular Strength Muscular Endurance Body Composition Slide 21 Agonist vs. Antagonist Agonist: is a muscle that causes a desired motion and may also be called the prime mover. One muscle is contracting to achieve a desired movement. Antagonist: are muscles that have the potential to oppose the action of the agonist. Opposite muscle is being stretched. When the abdominal muscles are Contracted during a bent-knee sit-up, The erector spinae muscles are being stretched Slide 22 Sample Question You want to swim across the Great Salt Lake. You train for this by going to the pool 3 times/week and swimming 50 laps in 50 minutes. You want to swim across the Great Salt Lake. You train for this by going to the pool 3 times/week and swimming 50 laps in 50 minutes. List one way that you can increase time, but keep intensity the same. List one way that you can increase time, but keep intensity the same. Slide 23 Answer: increase to 100 laps in 100 minutes.