KAAP430 Exam 3 PDF

KAAP430 Exam 3 Chapters 10 & 11-Principles of Exercise Training Terminology -Muscular vs Aerobic Fitness- Muscular Fitness: - Muscular strength - Strength: maximal force that a muscle or group of muscles can generate - Static - Dynamic: varies by...

KAAP430 Exam 3 Chapters 10 & 11-Principles of Exercise Training Terminology -Muscular vs Aerobic Fitness- Muscular Fitness: - Muscular strength - Strength: maximal force that a muscle or group of muscles can generate - Static - Dynamic: varies by speed and joint angle - 1 RM: maximal weight that can be lifted with a single effort - Muscular power - Power: rate of performing work - Explosive aspect of strength - Power = force x (distance/time) - More important than strength for many activities - Field tests not specific - Typically measured with electronic devices - Muscular endurance - Endurance: capacity to perform muscle contractions (or sustain a single contraction over time) - Common tests: sit-ups, push-ups - Number of repetitions at given 1RM - Increased through - Gains in muscle strength - Changes in local, metabolic, and cardiovascular function Aerobic Fitness - Aerobic Power - Rate of energy release by oxygen-dependent metabolic processes - Maximal aerobic power: maximal capacity for aerobic resynthesis of ATP - Synonyms: Aerobic capacity, maximal O2 uptake (VO2 max) - Primary limitation: cardiovascular system - Can be tested in lab or estimated from wide variety of field tests - Anaerobic Power - Rate of energy release by oxygen-independent metabolic processes - Maximal anaerobic power: max capacity of anaerobic systems to produce ATP - Also known as anaerobic capacity - Maximal accumulated O2 deficit test  - Critical power test - Wingate anaerobic test Adaptations to Resistance Training -Types of muscle contractions- Concentric = muscle shortening - A dynamic muscle contraction involving shortening of the sarcomeres as the muscle develops tension - Results in positive external work - Primarily responsible for acceleration in movement - Examples - Bicep curl upward motion - Leg press machine pushing the weight away from you - Walking up stairs - Running uphill Eccentric = muscle lengthening - Production of tension within the muscle by lengthening the muscle fibers - Results in negative work - Primarily responsible for deceleration in movement - Examples - Bicep curl downward motion - Leg press machine lowering the weight toward you - Walking down stairs - Running downhill Isometric = no change in muscle length despite increase in tension - Benefits include: - Building muscle - Improving balance - Improving strength - Improving range of motion - Examples: - Planks - Wall Sits - Squat Holds -Resistance Training: Gains in Muscular Fitness- The neuromuscular system is one of the most responsive systems to training After 3 to 6 months of resistance training - 25 to 100% strength gain - Learn to more effectively produce force  - Learn to produce true maximal movement Strength gains similar as a percent of initial strength (relative gains) - Young men experience the greatest absolute gains versus young women, older men, children Mechanisms of Muscle Strength Gain Hypertrophy vs atrophy - Increase in muscle size = increase in muscle strength (hypertrophy) - Decrease in muscle size= decrease in muscle strength (atrophy) Strength gains result from increases in muscle size and altered neural control Strength gan cannot occur without neural adaptations - Strength gain can occur without hypertrophy - Property of neuromotor system, not just muscle Motor unit recruitment - Normally motor units recruited asynchronously - Synchronous recruitment = strength gains - Facilitates contraction - May produce more forceful contraction - Improves rate of force development - Increass capability to exert steady forces - Resistance training -> synchronous recruitment - Strength ay also result from increased motor unit recruitment and increased frequency of discharge (rate coding) - Increased frequency of neural discharge - Increased neural drive during maximal contraction - Decreased inhibitory impulses - Trained muscles generate a given amount of submaximal force with less EMG activity - Suggests a more efficient motor unit recriutment pattern - Likely that some combination of improved motor unit synchronization and motor unit recruitment = strength gains Autogenic inhibition - Normal intrinsic inhibitory mechanisms - Golgi tendon organs - Inhibit muscle contraction if tendon tension too high - Prevent damage to bones and tendons - Resistance training can decrease inhibitory impulses - Muscle can generate more force  - May partially explain strength gains without hypertrophy Muscle hypertrophy: increase in muscle size - Transient hypertrophy (after exercise bout) aka “Muscle Pump” - Due to edema formation from plasma fluid - Disappears within hours - Chronic hypertrophy (long term) - Reflects actual structural change in muscle - Fiber hypertrophy (size), fiber hyperplasia (number) - Or both Primary Signal for Increased Protein Synthesis What increase protein sysntheis? - Resistance Exercise - Insulin - Amino Acids Mechanisms of Muscle Strength Gain Chronic Muscle Hypertrophy - Greatest hypertrophy and strength occur from eccentric training - Maximized by - High velocity eccentric training - Disrupts sarcomere Z-lines (protein remodeling) - Concentric training may limit muscle hypertrophy, strength gains Fiber Hypertrophy - More myofibrils, actin & myosin filaments - More sarcoplasm - More connective tissue Resistance training -> increased protein synthesis - Muscle protein content always changing - During exercise: synthesis decreases , degradation increases - After exercise: synthesis increases, degradation decreases Testosterone facilitates fiber hypertrophy - Natural anabolic steroid hormone - Synthetic anabolic steroids -> large increases in muscle mass Evidence of Hyperplasia - Cats - Intense strength training leads to fiber splitting - Each half grows to size of parent fiber - Chickens, mice, rats - Intense strength training leads to only fiber hypertrophy - But difference may be due to training regimen - Humans - Most hypertrophy but fiber hyperplasia can contribute - May depend on resistance training intensity/load - Higher intensity= (type II) fiber hypertrophy - Hyperplasia may only occur in certain individuals under specific conditions - Can occur through fiber splitting and satellite cells - Myogenic stem cells - Involved in skeletal muscle regeneration - Activated by stretch, injury - After activation, cells proliferate, migrate, fuse Fiber type alterations - Training regimen may not outright change fiber type, but - Type II fibers bacome more oxidative with aerobic training - Type I fibers become more anaerobic with anaerobic training - Fiber type conversion possible under certain (experimental?) conditions - Suggested in animal models - Cross-innervation - Chronic low-frequency stimulation - High-intensity treadmill or resistance training - Humans - Type IIx -> Type IIa transition common w/ RT  Neural activation and hypertrophy summary: - Short term increase in muscle strength - Substantial increase in 1RM - Due to increase in voluntary neural activation - Neural factors critical in first 8-10 weeks - Long tern increase in muscle strength - Associated with significant fiber hypertrophy - Net increase protein synthesis takes time to occur - Hypertrophy major factor after first 10 weeks General Principles of Training -RT Programs: Strength, Hypertrophy, and Power- Should involve the following types of contractions - Concentric - Eccentric - Isometric Recommendation for exercise order - Large muscle groups before small - Multijoint before single joining - Hugh intensity before low Rest periods based on experience - Novice: 2-3 mins - Advanced: 1-2 - Depends on type of training (strength vs hypertrophy vs power vs endurance) Principle of Individuality Not all athletes created equal Genetics affects performance Variation in - Cell growth rates - Metabolism - Cardiorespiratory - Neuroendocrine regulation Explains high vs low responders Principle of Specificity Exercise adaptations specific to exercise - Mode - Intensity - Duration  Training program must stress most relevant physiological systems for given sport Principle of Reversibility Use it or lose it Training leads to improved strength and endurance Detraining reduces gains Maintenance plan is important Principle of Progressive Overload Must increase demands on body to make further improvements Overload: muscles must be loaded beyond normal loading for improvement Progressive training: as strength increases, resistance/repitions must increase to further increase strength Principle of Variation Also called principle of periodization Systematically changes one or more variables to keep training challenging - Intensity, volume, and/or mode - Increase volume, decrease intensity - Decrease volume, increase intensity Macrocycles vs mesocycles Acute vs Delayed Onset Muscle Soreness Acute: usually occurs shortly after exercise & disappears within min or hrs - “Muscle strain” - Accumulation of chemical byproducts & tissue edema - No structural damage to the muscle Delayed-onset Muscle Soreness (DOMS): felt 12-48 hrs following exercise - Strenuous or first-time exercise - Accentuated with eccentric activity - May be caused by structural damage & inflammatory response Delayed Onset Muscle Soreness Structural Damage - Cell membrane rupture - Cellular contents spill into extracellular space - Z-disc “streaming” - Disruption of thick & thin filaments (myosin/actin) - Precipitating factor for muscle hypertrophy Inflammatory Reaction  - Defense mechanism against conditions which threaten normal function of tissues - Substances released from injured muscle signal to circulating inflammatory cells and activate inflammatory response DOMS and Performance Force-generating capacity is impaired - Physical disruption in muscle - Failure of excitation-contraction process - Loss of contractile proteins - Glycogen resynthesis Ways to Minimize DOMS: - Reduce eccentric component of muscle action in early training - Start training at very low intensity, gradually increase - Or….Begin with high intensity, exhaustive eccentric exercise bout - Causes soreness early, subsequent training bouts cause less soreness Resistance training and diet Muscle protein content always changing - During exercise: synthesis decreases, degretation increases - After exercise: synthesis increases, degradation decreases - Net positive protein balance required for hypertrophy Increased protein intake within a few hours to 24 hrs post traning supports muscle anabolism Dietary reference intake: 0.8 g/kg/body weight per day DRI for resistance training athletes: 1.5-1.7 g/kg/ body weight per day - 20-25 g immediately after training bout (high quality protein +(CHO)) - Can be repeated every ~2 hrs for several hrs Detraining Leads to decrease in 1RM - Strength losses can be regained (~6 weeks) - New 1RM matches or exceeded old 1RM Once training goal met, maintenance resistance program prevents detraining - Maintain strength and 1RM - Reduce training frequency Sarcopenia Loss of fat-free muscle mass with aging - Results from aged muscle’s inability to respond to anabolic stimuli Strength training in older adults Increases in strength dependent primarily on neural adaptations Same response as in younger but blunted - Decreased mTOR signaling response - Smaller increases in myofibrillar protein and muscle size - 25-50 grams protein necessary to stimulate muscle protein synthesis Elderly - Helps restore age-related loss of muscle mass - Improves quality of life and health - Helps prevent falls Resistance training for special populations Children and adolescents - Myth: resistance training unsafe due to growth plate, hormonal change - Truth: safe with proper safeguards - Children can gain both strength and muscle mass Muscular Strength Maximal force a muscle group can activate - Static - Dynamic 1RM-max weight in one rep Muscular Power Rate of performing work Force x (distance/time) Explosive Muscular Endurance Ability to perform repeated muscle contractions or sustain one Increased through increased strength gains Performed at given percentage of 1RM —------- Aerobic Power Energy release by oxygen-dependent processes Maximal Aerobic Power - Vo2 Max Anaerobic Power Energy release by oxygen-independent processes Maximal anaerobic power - Wingate —------ Adaptations to Resistance Training (RT) Types of Muscle Contractions Concentric - Muscle shortening - Positive external work - Acceleration in movement Eccentric - Muscle lengthening - Negative external work - Deceleration in movement Isometric - No change in length despite tension Resistance Training: Gains in Muscular Fitness Neuromuscular system is one of the most responsive systems to training After 3-6 months - 25-100% strength gain