Lecture 23 Effect of Exercise on Skeletal Muscle Claudia Stanescu Ph D Office hours Tuesday and Thursday 1 2pm in Gittings 108 or by appointment Extra office hours posted on D2L Objectives pg 317 sec 10 7 1 List and describe the effects of exercise training on muscle 2 Define muscle hypertrophy and muscle atrophy Exercise effects on muscle Basic principle of exercise and response of muscle Muscle will change in response to the stresses it encounters Adaptations 1 Increased capillary density 2 Increased mitochondrial density 3 Increased cross sectional area Increased capillary density Before exercise capillaries After exercise Green H et al 1998 Regulation of fiber size oxidative potential and capillarisation in human muscle by resistance exercise Am J Physiol 276 R591 R596 Increased mitochondria density Aerobic exercise Broskey NT Skeletal muscle mitochondria in the elderly J Clin Endocrin Metab 99 1852 1861 May 2014 Increased cross sectional area Coronal MRI shows increased cross sectional area CSA with resistance training Axial Quadriceps VL Quadriceps VL Skeletal muscle hypertrophy and structure and function of skeletal muscle fibres in male body builders J Physiol 2006 vol 570 no 3 611 627 Muscle hypertrophy and atrophy With training each muscle fiber increases in diameter increased of myofibrils More sarcomeres in parallel more cross bridges more force Training hypertrophy Detraining atrophy Changes after strength vs endurance training hypertrophy hypertrophy capillary density mitochondria capillary density mitochondria Suggested Learning Activities Create a table listing the training adaptations that occur with endurance vs strength training
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