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Objectives
By studying this chapter, you should be able to do the following:
Identify the neural pathways involved in muscle contraction.
Contrast the role of neural adaptations versus increases in muscle mass and fiber specific force production on the increase in strength following resistance training.
Describe the impact of aging on strength and the influence of resistance training on strength in older individuals.
Discuss the resistance training–induced changes that occur in the nervous system that contribute to increases in muscle strength.
Identify the biochemical changes that occur in skeletal muscle fibers in response to resistance training.
Describe the resistance training–induced changes that occur in tendons, ligaments, and bone.
Discuss the time course of muscle protein synthesis following a bout of resistance exercise.
Outline the signaling events that lead to resistance training–induced increases in muscle growth.
Describe the role that hormones and satellite cells play in resistance training–induced hypertrophy.
Discuss how detraining following strength training affects muscle fiber size and strength and explain how retraining affects muscle fiber size and strength.
Describe the cellular events that lead to inactivity-induced muscle atrophy.
Define muscle memory and discuss a potential mechanism that may contribute to muscle memory.
Explain why concurrent strength and endurance training can impair strength gains.
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Outline
Physiological Effects of Resistance Exercise Training
Resistance Training Promotes Changes in the Nervous System
Resistance Training–Induced Changes in Muscle Fiber Type
Does Resistance Training Improve Muscle Oxidative Capacity and Increase Capillary Number?
Resistance Training Improves Muscle Antioxidant Enzyme Activity
Resistance Training Increases Tendon and Ligament Strength
Resistance Training Improves Bone Mineral Content
Time Course and Signaling Events Leading to Resistance Training–Induced Muscle Growth
Time Course of Muscle Protein Synthesis
Signaling Events Leading to Resistance Training–Induced Muscle Growth
Do Hormones Contribute to Resistance Training–Induced Hypertrophy?
Do Anti-inflammatory Drugs Impact Training–induced Hypertrophy?
Role of Satellite Cells in Resistance Training–Induced Hypertrophy
Genetic Influence on the Magnitude of Resistance Training–Induced Hypertrophy
Detraining Following Strength Training
Prolonged Inactivity of Skeletal Muscles Leads to Rapid Atrophy
Concurrent Strength and Endurance Training
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Key Terms
agonist
antagonist
hyperplasia
leucine
muscle atrophy
muscular endurance
neural drive
one-repetition maximum
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Any type of regular exercise (e.g., endurance exercise or resistance exercise) promotes adaptations in skeletal muscles. However, the physiological adaptations that occur in muscles are specific to the type of exercise training. Indeed, the skeletal muscle adaptations that occur in response to endurance exercise training differ markedly from the alterations that follow resistance training (also called strength training). For example, endurance exercise training (e.g., running, cycling, etc.) results in limited changes in skeletal muscle mass and strength whereas several weeks of resistance exercise training increases both muscle size and strength. These differences in training adaptations are due to the variations in both the intensity and number of muscle contractions. For example, during 60 minutes of moderate-intensity endurance exercise, the active muscles work at ...