Neuromuscular Adaptations to Resistance Training Chapter 19 u Strength u Power u Endurance

Strength u Muscular strength is the maximum amount of force a muscle or group of muscles can generate.

Power u Muscular power is the product of strength and the speed of movement. u Though two individuals may have the same strength, if one requires less time than the other to move an identical load the same distance, the first individual has more power.

Muscular Endurance u Muscular endurance is the ability of your muscles to sustain repeated muscle actions or a single static action.

Neural adaptations u Neural adaptations always accompany the strength grains that result from resistance training, but hypertrophy might or might not be present.

Neural adaptations u Neural mechanisms leading to strength gains can include recruitment of more motor units to act synchronously and decreases in autogenic inhibition from Golgi tendon organs.

Neural adaptations u When the tension on a muscle’s tendons and internal connective tissue structures exceeds the threshold of the imbedded Golgi tendon organs, motor neurons to that muscle are inhibited. u This reflex is called autogenic inhibition.

Muscle adaptations u Transient muscle hypertrophy is the pumped-up feeling you get immediately after an exercise bout. u It results from edema and is short-lived.

Muscle adaptations u Chronic muscle hypertrophy occurs from repeated resistance training and reflects actual structural changes in the muscle.

Steroid Induced Hypertrophy

Muscle adaptations u Although most muscle hypertrophy probably results from an increase in the size of individual muscle fibers (fiber hypertrophy), some evidence suggests that an increase in the number of muscle fibers (hyperplasia) might also be involved.

Muscle adaptations u Muscles will atrophy, meaning they decrease in size and strength, when they become inactive, such as with injury or disuse.

Muscle adaptations u Atrophy begins very quickly if training is stopped. u Training can be reduced, as in a maintenance program, without resulting in atrophy or loss of strength.

Fiber adaptations u One fiber type can take on characteristics of the opposite type in response to training.

Fiber adaptations u Evidence indicates that one fiber type might actually be converted to the other type as a result of cross-innervation or chronic stimulation.

Muscle Soreness u Acute muscle soreness occurs late in an exercise bout and during the immediate recovery period.

Muscle Soreness u Delayed-onset muscle soreness (DOMS) occurs a day or two after the exercise bout.

Muscle Soreness u Eccentric action seems to be the primary instigator of this type of soreness.

Muscle Soreness u Proposed causes of DOMS include structural damage to muscle cells and inflammatory reactions within the muscles.

Muscle Soreness u Armstrong’s proposed model of the sequence of events that cause DOMS includes: u structural damage u impaired calcium availability leading to necrosis u accumulation of irritants u increased macrophage activity

Muscle Soreness u Muscle soreness can be prevented or minimized by: u reducing the eccentric component of muscle action during early training u starting training at a low intensity and gradually increasing it, or, u beginning with a high-intensity, exhaustive bout, which will cause much soreness initially but will decrease future pain.

Resistance Training u Resistance training actions can use static or dynamic actions. u Dynamic actions include the use of free weights, variable resistance, isokinetic actions, and plyometrics.

Resistance Training u A needs analysis should be completed before designing a training program to tailor the program to the exerciser’s specific needs.

Resistance Training u Low-repetition, high-resistance training enhances strength development u High repetition, low-intensity training optimizes muscular endurance

Resistance Training u Periodization, through which various aspects of the training program are varied, is important to prevent overtraining or burnout. u Typically the goal is to gradually decrease volume while increasing intensity.

Periodization u A typical cycle has four phases, each emphasizing a different muscle fitness component, plus an active recovery phase.

Resistance Training u Strength gains are highly specific to the speed of training and the movement patterns used in training.

Resistance Training u For maximum benefit, a resistance training program must include activities quite similar to those experienced by the athlete in actual performance.

Age-related Resistance Training u Resistance training can benefit almost everyone, regardless of a person’s gender, age, or athletic involvement.

Age-related Resistance Training u Most individuals can benefit from resistance training if an appropriate program is designed for them.

Age-related Resistance Training u But to ensure that the program is working, performance should be assessed periodically and adjustments made to the training regime as needed

Considerations for Special Populations: u 1. Young. u 2. Older. u 3. Cardiac patients.