Ex Phys Exam 3 Study Guide PDF

Exam 3 Study Guide CHAPTER 7 & 8 BODY COMPOSITION METHODS - Underwater weighing o Measures body density by water displacement, leaner individuals weigh more underwater and tend to sink o Based on Archimedes’ principle - BodPod o Measures body volume using air...

Exam 3 Study Guide CHAPTER 7 & 8 BODY COMPOSITION METHODS - Underwater weighing o Measures body density by water displacement, leaner individuals weigh more underwater and tend to sink o Based on Archimedes’ principle - BodPod o Measures body volume using air displacement o Calculates density via Boyle’s law o Most practical, good cause comfort, ease of use, time efficient - DEXA (Duel Energy X-ray Absorptiometry) o Uses x-rays to measure fat, lean mass, and bone mineral density o Gold standard - Skinfolds o Measures thickness of subcutaneous fat with calipers o 3-5% error rate o Older populations have less subcutaneous fat, diabetes has more visceral fat - BMI (calculation) o Weight to height ratio, used as a general health indicator o Doesn’t account for fat distribution o [WT / HT^2 (kg x m2)] ▪ 18-25 is normal range o If a 30 yo female weighs 165 lbs and is 5’8” tall, what’s her BMI? ▪ 165 lbs / 2.2 = 75 kg ▪ 5’8” in = 68 in x 2.54 cm = 172.72 cm = 1.73 m ▪ 75 kg / 1.73^2 = 25.2 - Waist-to-Hip Ratio o Circumference of waist to hips o High ratios indicate more visceral fat, or obesity o Average for women = 0.80, men = 0.90 o WC >99-102 = abdominal obesity - BIA (bioelectrical impedance) o Uses electrical currents to estimate body’s water and fat-free mass o Fat resists more than lean tissue o Heat and water, lower body fat percent if hydrated ADIPOSE CELLS - Hypertrophy o Fat cells grow larger to store excess lipids when an excess of them are stored o Contributes to obesity - Hyperplasia  o Fat cells increase in number when hypertrophy reaches capacity - Beige/brown fat o High mitochondria content, generates heat, unlike white o Helping with thermogenesis and energy expenditure o Fully submerge, synthesize beige and brown fat cells - We synthesize adipose as adolescence, critical time o They don’t die, they shrink o Higher in females IMPACT OF EXERCISE ON DIET - With consistent exercise, increase in muscle increases hunger, but a decrease in fat decreases leptin therefore decreasing hunger o Leptin is produced in fat so less fat, less leptin more hunger control ▪ Leptin tells you when you’re full, if there’s high levels, it can lead to leptin resistance and the brain ignores its signals. When you exercise and levels drop, your body becomes more sensitive to its signals, improving appetite regulation and prevents overeating ▪ Carbs tend to spike leptin best o Vicious cycle bc lower fat and leptin improve hunger control but increased muscle may increase hunger o NOT sex specific o NO impact after one day of working out ▪ You have 1-2 weeks before food intake needs to be compensated - Thyroid hormone is a big one BASAL METABOLIC RATE (BMR) - Basal metabolic rate (BMR) and resting metabolic rate (RMR) both represent the energy needed to sustain vital functions o Males tend to have higher BMR - Resistance training and muscle mass will increase RMR, caloric restrictions will reduce it IMPACT OF DIET AND EXERCISE ON RMR - Short term o Exercise boosts metabolism but not your resting metabolism, so the extra calories burned comes from the activity itself and the recovery process (EPOC) ▪ Burns extra calories after to return to its resting state ▪ Metabolism increases, calorie restrictions decrease it, so to decrease metabolism, your body keeps burning calories after exercise to return to its resting state ▪ Resistance training burns more after the workout than cardio - Long term o Resistance training can increase RMR because you’re building muscle which is more metabolically active than fat ▪ The more muscle you have, the more energy your body needs at rest  ▪ But the impact of muscle on daily calorie burn is small, 1 lbs of muscle only burns about 6 extra calories per day ▪ So the increase in RMR is modest but can still contribute - Exercise preserves lean mass and burns calories, while diet creates calorie deficits for fat loss, when combined they improve body composition and metabolic health - Energy before and energy after exercise needs to be the same o Energy intake is food and drink o Energy expended is BMR/RMR’s thermogenesis, exercise, waste EFFECTS OF DIET AND EXERCISE TRAINING ON BODY COMPOSITION AND WEIGHT - The more restricting a diet and less caloric intake showed the most muscle gained and least amount of fat o Should have a low kcal diet but not lower than RMR, 1,200 for females and 1,500 for males o Also should have diet of 45-65% carbs, 10-35% protein, and 20-35% fat o Includes at least 3 meals a day and 74-100 oz of water - Regular training reduces fat mass, preserves lean tissue, and boosts metabolic health - Exercise alone may not cause significant weight loss without dietary changes o You can’t outwork a bad diet o Diet is 87% of the battle - Body fat raises inflammation o Supersedes cancer potentially - You need an energy deficit to lose weight IMPACT OF EXERCISE ON THE THERMIC EFFECT OF A MEAL - Thermic effect of nutrients, thermogenesis is needed to synthesize each nutrient o Fat = 2-3%, carbs = 6-8%, 25-30% for protein - Short term o If you eat a meal before or after exercise, both will increase the thermal effect of a meal ▪ So exercise enhances the thermal effect of a meal RESISTANCE TRAINING AND RMR/BMR - Resistance training increases lean muscle mass, which raises RMR slightly due to higher activity of lean tissue - Regular resistance training boosts resting metabolic rates by increasing lean muscle mass, which burns more calories at rest THERMOGENESIS - Exercise associated thermogenesis (EAT) and non-exercise associated thermogenesis (NEAT) contribute to daily energy expenditure - Thermal effect of feeding (TEF) o Thermogenesis is needed from the natural energy requiring processes like digestion, absorption, and synthesis of protein, fat, and carbs  o The thermic effect of feeding (TEF) is highest for protein (25-30%) ▪ Then carbs at 6-8% and lowest for fat at 2-3% - Exercise increases thermic energy expenditure, and protein rich diets amplify the thermic effect of feeding (TEF) TONIC AND EPISODIC APPETITE SIGNALS - Tonic signals: Regulate long term hunger and energy storage o E.g. leptin and insulin o Leptin = full, stop eating - Episodic signals: Regulate short term satiety (hunger) in response to meals o E.g. ghrelin and CCK o Ghrelin = high levels, means eat CHAPTER 17 SLIDING FILAMENT THEORY - Muscle contractions are the sliding of actin (thin) over myosin (thick) filaments, shortening the sarcomere - Cross-bridge cycling occurs, with myosin heads attaching to actin, pulling, and releasing, powered by ATP to produce force TITAN - Prevents overstretching of sarcomeres, acts as a string and provides a recoil of the sarcomere after it’s been stretched - Largest protein, acts as a molecular spring in the sarcomere, prevents overstretching, enhances passive force, and contributes to passive force and active contraction through stored elastic energy - Enhances muscle contraction during lengthening and shortening ALL OR NOTHING PRINCIPLE - A motor neuron’s action potential triggers all muscle fibers in its motor unit to contract fully or not at all, gradual force occurs from recruiting more motor units ORDER OF RECRUITMENT - Motor units are recruited sequentially based on size o Smaller, slower type 1 fibers are activated first for low intensity tasks o Larger, faster type 2a and 2x fibers as force requirements increase - Recruitment depends on the task’s force and intensity - Type I – Slow, small, low recruitment threshold, oxidative - Type IIa – Large, fast, high recruitment threshold, oxidative/glycolytic - Type IIx – Large, fast, high recruitment threshold, glycolytic o Males tend to have more of all fibers, particularly type 2a, females are more SO PARALLEL ELASTIC COMPONENT - The connective tissue elements (like titan) within muscle that provide passive resistance during stretching and contribute to the elasticity and stability of muscle fibers during movement - When you stretch, there is a force pulled in the opposite direction to prevent over stretching MUSCLE FIBER TYPES - Type 1 fibers (Slow Oxidative, SO) o Fatigue-resistant, slow-twitch fibers, rely on aerobic metabolism for endurance activities - Type IIA fibers (Fast Oxidative Glycolytic, FOG) o Intermediate fibers combining oxidative and glycolytic energy systems, moderate intensity tasks o More to this with 2x disuse - Type IIX fibers (Fast Glycolytic, FG) o Fast-twitch fibers relying on anaerobic glycolysis for short, explosive actions o Change to this with more resistance training - Fiber type shifting o Disuse: I → IIA → IIX o Use: IIA  IIX ▪ Aerobic training: I  IIA  IIX o Low intensity, high volume, and low velocity = more type I o High intensity, low volume, and high velocity = more type 2 and hypertrophy CHAPTER 18 MUSCLE CONTRACTIONS - Generate tension by cross-bridge cycling between actin and myosin, fueled by ATP - Can be classified as isometric (tension without movement), concentric (muscle shortens), or eccentric (muscle lengthens under tension) - Types of contractions o Isotonic: constant force production, bicep curl up and down o Isokinetic: constant velocity of lengthening or shortening, machines or swimming o Isometric: constant muscle length, holding a plank MECHANICAL FACTORS INFLUENCING MUSCLE CONTRACTIONS - Eccentric contractions: lower energy cost than concentric o Fewer muscle fibers are activated, requiring less oxygen and energy o Fewer cross-bridges cycle, less ATP is used compared to concentric  o Elastic energy stored in the muscle during lengthening reduces need for additional energy o Eccentric can feel easier because they recruit less muscle fibers and use less energy, but they create higher mechanical stress from the lengthening under tension, the energy demand is lower, but the structural strain is greater ▪ Which explains why it can lead to DOMS o At the bottom of a squat the sarcomere is stretched, there’s less actin and myosin binding sites, and greater force contribution from parallel elastic component (titan and everything that prevents overstretching) ▪ As titan stretches like a spring, the further you stretch that spring, the more it’s gonna resist o Countermovement jump is higher than normal squat because there’s a greater eccentric contribution and titan’s help is more pronounced ▪ You get higher with greater joint angles ▪ You preload the muscles and store elastic energy when you go down, which can be released when you go upward Also activates stretch reflex, increasing muscle recruitment ▪ During eccentric contraction, titan binds to actin and stretches it, as it stretches, elastic energy is generated and titan acts as a spring when shortening That’s why when you stop you don’t go as high, you take out the elastic component - Length-tension o Muscle generates maximum force at an optimal sarcomere length o Too short or too stretched reduces actin-myosin overlap, lowering force production o Weight feels heavier in lower squat because actin-myosin overlap is not as great - Cross sectional area o Larger correlates with greater force production, as more fibers can generate more tension - Recruitment o Follows the size principle, smaller motor units first (type I), then larger ones (type II) as force demands increase - Strength curve of exercise o Strength varies across joint angles o Ascending – you get stronger as the movement progresses (squats) o Descending – you’re stronger at the start and weaker toward the end (pullovers) o Bell-shaped curves – strength peaks mid movement (bicep curls) ROLE OF CALCIUM  - Essential for muscle contraction - After released from sarcoplasmic reticulum, it binds to troponin, causing tropomyosin to move and expose binding sites on actin filaments, allows myosin heads to attach to actin initiating the sliding filament process, leading to muscle contraction o When calcium is pumped back into storage, the muscle relaxes - Higher calcium levels increase actin-myosin binding, enhancing force o More calcium, more force F-V CURVE - Inverse relationship between force and velocity during contraction - At high velocities, fewer myosin-actin cross-bridges form because they don’t have as much time to bond, reducing force - At low velocities, more cross-bridges form because there is more time to bone, maximizing force output - Eccentric contractions allow for higher force production due to elastic contributions like titan DELAYED-ONSET MUSCLE SORENESS (DOMS) - Pain and stiffness occurring 24-48 hours after intense exercise, especially eccentric actions, symptoms subside within 96 hours - Results from microtrauma in muscle fibers, inflammatory responses, and fluid accumulation o High mechanical forces while contracting create structural damage, degradation of regulatory proteins, and inflammation - Treatment: NSAIDs, compression garments, massage o Icing and static stretching do NOT reduce symptoms CHAPTER 19 NEUROMUSCULAR ADAPTATIONS TO RESISTANCE TRAINING - Muscle function o Increases strength, endurance, and power - Muscle size and structure o Increases muscle fiber CSA and whole muscle cross-sectional area (CSA) o Connective tissues increase collagen synthesis and stiffness - Neural adaptations o Increase motor unit recruitment improves strength by activating more muscle fibers, better synchronization and firing rates (especially in type II fibers) o Decreases GTO reflex - Metabolic adaptations o Increase glycogen, phosphocreatine (PC), and creatine phosphokinase (CPK)  - Hormonal adaptations o Increase insulin like growth factor (IGF) o Nothing consistent for testosterone, GH, or cortisol HYPERTROPHY - Mechanisms o Motor unit recruitment: Engaging more motor units during training stimulates greater muscle growth o Mechanical stress/tension: Resistance training generates stress that signals the body to repair and enlarge muscle fibers o Stretch: Lengthening under load (eccentric contractions) promotes growth by stimulating mechanosensors and increasing sarcomere length - Contractions and muscle architecture o Resistance training increases both sarcomeres in parallel (thicker fibers) and sometimes sarcomeres in series (longer fibers), enhancing both force and flexibility o Eccentric contractions increase fiber length, cross-sectional area, and type II muscle size o Concentric contractions focus on increasing fiber diameter and CSA in the middle of the muscle - Functional vs Non-Functional Hypertrophy o Functional: Increases muscle size, or growth in myofibrils (contractile units), that directly improves strength and performance ▪ Increased jump height or relative strength o Non-functional: Increases sarcoplasmic fluid, which adds size not strength, growth contributes less to performance, such as increased intracellular fluid ▪ (sarcoplasmic hypertrophy) ▪ Bodybuilding focus - Training variables o Intensity: Higher intensities (>70% 1RM) favor functional hypertrophy by recruiting fast-twitch fibers o Rest: Longer rest (>60 sec) optimize recovery for strength and hypertrophy in trained individuals, shorter rest (