KIN 375 EXAM 4

Aging, Strength, and Training

- Decline in strength after age 50 --loss of muscle mass (sarcopenia) --loss of both type I and II fibers ---atrophy of type II fibers ---loss of intramuscular fat and connective tissue ---suppressed satellite cell function --loss of motor units --reorganization of motor units - Progressive resistance training --causes muscle hypertrophy and strength gains. --important for activities of day living, balance, and reduced risk of falls

Progressive resistance exercise

- Improvements in strength via progressive overload: periodically increasing resistance (weight lifted) to continue to overload the muscle. involves increases is load, # reps, and/or # sets - Basis for most weight-training programs

protein availability and muscle protein synthesis

- Ingesting protein increases rate of protein synthesis following training -- For both endurance and resistance training - Plan protein intake around workouts -- Both protein amount and timing

effects of endurance training on performance

- Maintenance of homeostasis. --more rapid transition from rest to steady-state, reduced reliance on glycogen stores, cardiovascular and thermoregulatory adaptations - Neural and hormonal adaptations --initial changes in performance - Structural and biochemical changes in muscle -- increase mitochondrial mass, increase capillary density

off season conditioning

- Prevent excessive weight (fat) gain - Maintain muscular strength or endurance - Maintain bone and ligament integrity - Maintain skill level -work on weaknesses

live high, train low

- Spend sleeping and resting time at altitude --Increases red blood cell volume and oxygen transport capacity of blood - Train at lower altitude - Better performance gains compared to living and training at sea level

supplementation with mega doses of antioxidants

- exercise promotes formation of free radicals - may damage cells and contribute to fatigue - antioxidant supplements may prevent damage and fatigue - however, high doses of antioxidants may block training adaptations - free radicals activate signaling pathways involved in muscle adaptation to training

In-season conditioning

- maintenance of fitness level --strength maintained w as little as 1 workout per week/ 10 days --cv fitness: at least 2-3 workouts / week - may incorporate periodized techniques

frequency

-2-4 sessions per week minimum -2 sessions with higher-intensity exercise -Gains level off after 3 to 4 sessions/week

ACSM recommendations

-3-5 sessions per week -20-60 min per session -Intensity of 40/50-85% HRR or VO2R -Should result in expenditure of 200-300 kcal per session -Consistent with weight loss and reducing CHD risk factors

slow decrease in strength

-31% decrease in strength following 30 weeks detraining -associated with small changes in fiber size -type I fiber size-2% -type IIa fiber size-10% -type IIx fiber size-14% -earlier change due primarily to nervous system changes

secondary messengers in skeletal muscle

-AMPK (glucose uptake, fatty acid oxidation, and mitochondrial biogenesis) -PGC-1a (increases in capillaries, mitochondria, antioxidant enzymes. activated by p38 and CaMK) -Calcineurin (fiber growth, fast to slow fiber type change) -mTOR (protein kinase major regulator of protein synthesis and muscle size) -NFkB (antioxidant enzymes)

static stretching

-Continuously holding a stretch position §Hold position for 10-60 seconds §Repeat each stretch 3-5 times -Preferred technique §Less chance of injury or soreness §Less muscle spindle activity

intensity

-Describes the overload needed to bring about a training effect -60%-80% of VO2 max §Lower in those with low initial fitness level -Target heart rate range

overtraining

-Workouts that are too long or too strenuous -Greater problem than undertraining -symptoms: •Elevated heart rate and blood lactate levels -At same submaximal work rate •Loss in body weight -Due to reduction in appetite •Chronic fatigue •Psychological staleness •Multiple colds or sore throats •Decrease in performance

periodization

-also includes variation of: --rest periods , type of exercise, number of training sessions, and training volume -develop workouts to achieve optimal gains in: --strength, power, motor performance, and/or hypertrophy -linear and undulating programs --variations in volume/intensity over time -more effective than on-periodized training for improving strength and endurance

rapid decrease in vo2 max

-decrease ~8% within 12 days -decrease 20% after 84 days

undertraining

-insufficient stimulus -adaptations not fully realized -optimal performance not achieved

Primary signals for muscle adaptation

-mechanical stretch -calcium (via calmodulin-dependent kinase) -free radicals -phosphate/muscle energy levels (AMP/ATP ratio activates AMPK)

ATP-PC system

-short (5-10 seconds) high intensity work intervals --30 yard dashes for football players -30-60 second rest intervals --little lactic acid is produced, so recovery is rapid

dual energy x-ray absorptiometry (DEXA)

-two x-ray beams are used to determine whole body and regional estimates of lean tissue, bone density, and fat -SEE = 1.8% -popular technique with several advantages -disadvantages include expensive and certifies medical personnel must perform the scan -expense -less accurate with some larger people

normal

18.5-24.9kg/m2

overweight

25-29.9 kg/m2

anaerobic training increases performance

4-10 weeks of sprint training can increase peak anaerobic power by 3-28% across individuals. -Sprint training improves muscle buffering capacity by increasing both intracellular buffers and hydrogen ion transporters -Sprint training also results in hypertrophy of type II muscle fibers and elevates enzymes involved in both the ATP-PC system and glycolysis -High intensity interval training >30 seconds (at near or above VO2 max) promotes mitochondrial biogenesis

underweight

<18.5 kg/m2

obesity

> 30 kg/m2

overweight for children

> or equal to 85th percentile for age and gender

obese for children

> or equal to 95 percentile for age and gender

expected increases in vo2 max for endurance training and vo2 max

Average = 15% 2-3% in those with high initial VO2 max Requires intensity of 95-100% VO2 max 30 to 50% in those with low initial VO2 max Training intensity of 40-70% VO2 max

preseason conditioning

- 8-12 weeks prior to competition - Increase to maximum the energy systems used in particular sports

strength training adaptations

Increased muscle force production - Proportional to muscle cross-sectional area Increased muscle mass - Hypertrophy Increased muscle fiber diameter Responsible for most of the increase in muscle size - Hyperplasia Increased number of muscle fibers central nervous system changes -increased motor unit recruitment -altered motor neuron firing rates -enhanced motor unit synchronization -removal of neural inhibition -conversion of IIx --> IIa fibers

primary and secondary signals lead to adaptations

Increased protein synthesis (contractile protein, mitochondrial mass)

physical activity intensity thresholds

Physical workloads should be assigned to meet individual abilities, goals, preferences. •Workloads can be easily assigned in METs. •Reminder: 1 MET = 3.5 ml · kg−1 · min−1. •Relative VO2 can be estimated from METs. MET physical activity intensity breakpoints reflect intensity-dependent health gains. •Low-intensity physical activity (LPA) 1.1 to 2.9 METs (<40% VO2max). •Moderate-intensity physical activity (MPA) 3 to 5.9 METs (40-60% VO2max). •Vigorous-intensity physical activity (VPA) ≥6 METs (>60% VO2max).

concurrent strength and endurance training

Potential for interference of adaptations - Endurance training increases mitochondrial protein - Strength training increases contractile protein - Depends on intensity, volume, and frequency of training Studies sow conflicting results - Depends on intensity, volume, and frequency of training -numerous studies report that combining strength and endurance training impairs strength gains compared to strength training alone

Increased maximal stroke volume

Preload (EDV) increases: plasma volume increases, venous return increases, and ventricular volume increases. Afterload (TPR) decreases: Arterial constriction decreases, and maximal muscle blood flow with no change in mean arterial pressure increases. Contractility increases.

decrease maximal a-vO2 difference

decrease mitochondria. decrease oxidative capacity of muscle. decrease type 2a fibers and type 2x fibers

detraining and vo2 max

decreases in vo2 max with cessation of training. decrease SV max, rapid loss of plasma volume decrease maximal a-vO2 difference. decrease mitochondria. decrease oxidative capacity of muscle (decrease type IIa fibers and type IIx fibers) initial decrease (12 days) due to decrease in sv max later decrease due to decrease a-vO2 max

hydrostatic (underwater weighing)

density = mass / volume measurement of body volume -subject is submerged in tank of water -weight of water displace = loss of weight when submerged -weight of water displaced is divided by density of water to calculate volume of water displaced. -volume is corrected for residual lung volume and gas in intestinal tract -subject comfort -residual volume estimation -low bone density can effect accuracy

computed tomography (CT scan)

detailed radiographic, cross sectional images from x-ray beam passing through tissues of different densities. delineates between different tissues/organs. excellent indicator of fat distribution

air displacement plethysmography (bod-pod)

determines body density through air displacement (change in pressure within a closed chamber) -correction for lung volume necessary - body hair can be problematic -expense -residual volume estimation -body hair

neural factors

early gains in strength (initial 8-20 weeks). adaptations (improved ability to recruit motor units, learning, coordination)

arteriovenous o2 difference

increase Muscle blood flow decrease SNS vasoconstriction Improved ability of the muscle to extract oxygen from the blood increase Capillary density Slows blood flow through muscle increase Mitochondrial number

primary signals in resistance training induced signaling events

increase muscle stretch (mechanoreceptor activation) promotes synthesis of phosphatidic acid and activation of the mTOR activator, Ras homolog enrich in brain (Rheb)

Structural and Biochemical Adaptations to endurance Training

increased capillary density. increased number of mitochondria. increase in oxidative enzymes (krebbs cycle, fatty acid cycle, electron transport chain). increased NADH shuttling system (nadh from cytoplasm to mitochondria). change in type of LDH (pyruvate vs. lactate)

Biochemical adaptations and plasma glucose concentration

increased utilization of fat and sparing of plasma glucose and muscle glycogen transport of FFA into the muscle. -increased capillary density -increased fatty acid binding protein and fatty acid translocase (FAT) transport of FFA from the cytoplasm to the mitochondria -higher levels of carnitine palnitoyltransferase and FAT mitochondrial oxidation of FFA -increased enzymes of beta oxidation --increased rate of acetyl-CoA formation --high citrate level inhibits PFK and glycolysis

warm up

increases cardiac output and blood flow to skeletal muscle. increases muscle temperature and enzyme activity. opportunity for stretching exercises (believed to reduce risk of muscle injury, may also be performed in cool down)

secondary signals in resistance training induced signaling events

increases in phosphatidic acid and rheb promotes mTOR (rapamycin) activation. mTOR activation promotes protein synthesis (a single bout can increase protein synthesis 50-100%)

lactate threshold

incremental intensity test with blood samples for lactate. -breakpoint for lactate accumulation identified

biochemical adaptations and blood pH

lactate production during exercise increased mitochondrial number -less carbohydrate utilization = less pyruvate formed increased NADH shuttled -less NADH available for lactic acid formation change in LDH type -heart form (H4) has lower affinity for pyruvate = less lactic acid formation

Training to increase VO2 max (FITT)

large muscle groups, dynamic activity. 20-60 min, 3-5 times/week, 50-85% vo2 max (~60-90% hrmax)

muscular strength

maximal force that a muscle or muscle group can generate. 1 repetition maximum

standard error of measurement

measure of variation between predicted value and the true value

exercise economy

metabolic and mechanical factors influencing movement economy

training

mitochondrial mass can double within five weeks

ballistic stretching

more injury, soreness, generally less effective -muscle spindle activity may initiate reflexive contraction

central command

motor cortex, cerebellum, basal ganglia -recruitment of muscle fibers (trained fibers --> less recruitment) -stimulates cardiorespiratory control center

Responses to Resistance Training-Induced Signaling Events

muscle hypertrophy due to increase myofibrillar proteins. increased number of myonuclei in each fiber (derived from satellite cells, increases in myonuclei may be important to support increased muscle protein synthesis as fiber increases in size)

strength training

percent gain inversely proportional to initial strength (genetic limitation to gains in strength) -high resistance (2-10 rm) training (gains in strength) -low resistance training (20+ rm) (gains in endurance)

differences in VO2 max in different populations

primarily due to differences in SV max

endurance exercise induced signaling events

primary signals (increase calcium, increase AMP/ ATP, increase free radicals), secondary signals (increase calcineurin, increase PCG-1a, increase NFkB) responses -fast to slow fiber type shift -mitochondrial biogenesis -antioxidant enzyme synthesis

calculation of vo2 max using the fick equation

product of maximal cardiac output and arteriovenous difference. vo2 max = hr max x SV max x a-vO2 difference max

Training to Improve Aerobic Power

purpose: overload the circulatory system & stress the oxidative capacity of skeletal muscle - three methods > interval training > long, slow distance > high-intensity, continuous exercise - should be geared toward improving: > VO2 max > lactate threshold > running economy

decrease sv max

rapid loss of plasma volume

body composition

refers to makeup of tissues of the body-often used in reference to % body fat. -most common model is two compartment model: 1) fat mass; and 2) fat free mass three compartment model 1) fat mass 2) muscle mass 3) bone mass

anaerobic exercise

refers to short duration (10-30 seconds) all-out effort which is referred to as sprint training -recruits both type 1 and II muscle fibers to perform the exercise -during exercise lasting 10 seconds or less, the energy is primarily supplies by ATP-PC system -during exercise lasting 20-30seconds , 80% of energy needed is provided anaerobically whereas remaining 20% is provided aerobically

resistance training improves antioxidant capacity in trained muscles

resistance training induced increases in muscle antioxidant enzyme activity is similar to the changes observed following endurance exercise training

screening

risk of cardiovascular complications is related to degree of pre-existing cardiac disease

dynamic stretching

stretching movements with control

critical power

submaximal power output that can be maintained for indefinite periods

muscle soreness

•Delayed onset muscle soreness (DOMS) -Appears 24-48 hours after strenuous exercise -Due to microscopic tears in muscle fibers or connective tissue §Results in cellular degradation and inflammatory response §Not due to lactic acid -Eccentric exercise causes more damage than concentric exercise -Slowly begin a specific exercise over 5-10 training sessions to avoid DOMS

Long, slow distance training

•Low-intensity exercise -57% VO2 max or 70% HRmax •Duration greater than would be expected in competition •Based on the idea that training improvements are based on volume of training -However, more is not always better §1.5 hours/day training results in better performance than 3 hours/day §Quality versus quantity? §Injury risk

tapering

•Short-term reduction in training load prior to competition •Allows muscles to resynthesize glycogen and heal from training-induced damage •Improves performance in both strength and endurance events -Athletes can reduce training load by 60% without a reduction in performance -Successful tapers usually last 1-3 weeks

physiological mechanisms causing increased strength

•Strength training results in increased muscle size and strength •Initial 8-20 weeks -Neural adaptations •Long-term training (20+ weeks) -Muscle hypertrophy -High-intensity training can result in hypertrophy with 10 sessions

steps leading to DOMS

•Strenuous muscle contraction results in myofilament damage •Membrane damage occurs -Including sarcoplasmic reticulum •Calcium leaks out of SR and collects in mitochondria -Inhibits ATP production -Activates proteases which degrade contractile proteins •Results in inflammatory process -Increase in prostaglandins/histamines •Edema and histamines stimulate pain receptors

gender differences in response to strength training

•Untrained males have greater absolute strength than untrained females -50% stronger in upper body, 30% stronger in lower body •However, strength related to cross-sectional area of muscle is similar -3-4 kg of force per cm2 of muscle in males and females •There does not appear to be a gender differences in response to short-term strength training -Men exhibit greater hypertrophy as a result of long-term training §Due to higher testosterone levels

Carbohydrate Availability and Endurance Training Adaptations

Low muscle glycogen is a positive influence on endurance training-induced adaptations. •Promotes increased protein synthesis and mitochondria formation. •Due to higher activation of PGC-1α. Two approaches. •Restrict dietary carbohydrates. •May cause fatigue and limit training. •Train twice per day (every other day). •Second training session with lower muscle glycogen.

physical activity and guidelines for improved health

Modern E x Rx are founded on public health recommendations developed over the last 25 years. •1995, 2007, 2008, 2018. The ACSM/CDC first produced physical activity guidelines 1995. •Every U.S. adult should accumulate thirty minutes or more of moderate-intensity (3-6 METs) physical activity on most, preferably all, days of the week. Dept of HHS Physical Activity Guidelines for Americans 2nd edition (2018). •Most recent, most comprehensive recommendations.

injuries and endurance training

Most injuries are a result of overtraining - Short-term, high-intensity exercise - Prolonged, low-intensity exercise • The "ten percent rule" for increasing training load - Increase intensity or duration ≤10% per week • Other injury risk factors - Strength and flexibility imbalance - Footwear problems - Malalignment - Poor running surface - Disease (arthritis)

physical activity volume

Physical activity volume recommends 30+ minutes of PA most/all days of the week. •Perform 150 to 300 min of moderate-intensity PA per week or •Perform 75 to 150 min of vigorous-intensity PA per week (> 6 METs) •or some combination of the two. •150 min of MPA or 75 VPA is the minimum goal. •The range of physical activity indicates that health benefits accrue with more activity (that is, more is better). •Dose-response relationship Physical activity volume recommendations continued. •Adults should move more and sit less. •Physical activity can be done in multiple intermittent bouts (example: 5 to 10 min each) to meet the goal. •For those unable to meet the 150 min weekly goal, achieving as much activity as possible will still improve health. •Adults should perform muscle strengthening exercises at least 2 days per week. •Focus on all major muscle groups. •Perform at moderate to high intensities when possible.

Dynamic, large muscle activities

Walking, jogging, running, swimming, cycling, rowing, dancing

isometric or static

application of force without joint movement

Links Between Muscle and Systemic Physiology

biochemical adaptations to training influence the physiological response to exercise (sympathetic nervous system, decrease e/ne. cardiorespiratory system, decrease hr, decrease ventilation) due to : -reduction in feedback from muscle chemoreceptors -reduced number of motor units recreuited demonstrated in one-leg training studies -lack of transfer of training effect to untrained leg

traditional training programs

variations in intensity (RM), sets, and repetitions

ventilatory threshold

ventilatory response to incremental work produces increased slop. -ventilatory break point identified

high-intensity, continuous exercise

•Appears to be the best method of increasing VO2 max and lactate threshold •High-intensity exercise -At or slightly above lactate threshold -80-90% HRmax --≥90% HRmax or 95% HRR also suggested •Duration of 25-50 min -Depending on individual fitness level

hypertrophy

-Enlargement of both type I and II fibers §Low-intensity (high RM), high-volume training results in smaller type II fibers than with low RM training §Heavy resistance (low RM) results in larger type II fibers -No increase in capillary density -Lower mitochondrial density

indirect method

-Heart rate reserve (Karvonen) method §Subtract resting HR from maximal HR to obtain HRR §Take 60% and 80% of HRR §Add each HRR to resting HRR to obtain THR range -Percentage of maximal HR §Take 70% and 85% of maximal HR as THR range -Use RPE scale in addition to HR §RPE of 12-16 is about 40/50-85% HRR

hyperplasia

-Increase in muscle fiber number -Evidence suggested mostly from long-term strength training §Not as much evidence as muscle hypertrophy

Proprioreceptive Neuromuscular Facilitation (PNF)

-Preceding a static stretch with isometric contraction of muscle being stretched §Contraction stimulates Golgi tendon organ -Requires a training partner

interval training (HIIT)

-Repeated exercise bouts --Separated by brief recovery periods -Work interval --Distance to be covered --Intensity: 85-100% HRmax --Duration: >60 seconds to improve VO2 max -Rest interval --Light activity such as walking/jogging --Rest interval should usually be at least as long as work interval -Number of interval sets and repetitions --Depends on purpose of training and fitness level -Training outcomes of HIIT. --Improved VO2max, running economy, and lactate & ventilatory threshold better than low-intensity intervals.

glycolytic system

-Short (20-60 seconds), high-intensity work intervals -very demanding training --acutely reduces muscle glycogen stores --May alternate hard and light training days

progression

-Start with moderate-intensity activity §Walking 3-4 mph -Then increase duration and/or intensity §Walk®walk/jog®jog

Training to Improve Flexibility

-Stretching exercises improve flexibility and efficiency of movement -Limited evidence that flexibility reduces injury risk

Periodization of Strength Training

-Systematic variation of volume and intensity over time -Achieve optimal gains in strength, power, motor performance, and/or hypertrophy (Over the course of a season, year, or career) -Linear periodization (Shift from high volume/low intensity to low volume/high intensity training) -Strength gains greater with periodized programs

direct method

-THR range determined from maximal GXT -HR at 60-80% VO2 max

duration

-Total work per session should be 200-300 kcal -Must be considered with intensity

Assessing Body Fat Distribution

A total waist measurement of more than 40 inches (102 cm) for males and 35 inches (88 cm) for females are associated with increased risk of heart disease and diabetes. •Standardized measurement sites (most common) •Iliac crest (a lot of criteria for waste conference comes from using this measure) •Minimal waist •Umbilicus

Bioelectrical Impedance Analysis (BIA)

BIA to estimate body composition. •Simple, fast technique to estimate body composition. •Principle of operation: small electrical current is applied to one extremity and the voltage drop (impedance) is measured at another extremity. •Lean tissue (mostly water and electrolytes) is a good conductor of electricity (low impedance). •Fat tissue is a poor conductor of electricity (high impedance). •Impedance value provides an estimate of total body water from which both fat-free and fat mass can be calculated (SEE = 3.5 to 5%). •Hydration status is important! -hydration status

underwater weighing and air displacement plethysmography

Both methods assess body density to estimate % body fat. •Body divided into fat-free and fat mass. •Fat mass density = 0.900 g/mL (lower) •Water density = 0.997 g/mL (at 25˚C) •Fat-free mass density = 1.100 g/mL (higher) •Measurement of body composition. •Density = mass / volume. •Underwater weighing or air displacement plethysmography used to measure body volume. •% Body fat = (495 ÷ density)−450. •Underwater weighing S E E = 2.7 (gold standard technique). •Air displacement plethysmography S E E = 2.2 to 3.7.

peripheral feedback from working muscles

Group III and group IV nerve fibers - Responsive to tension, temperature, and chemical changes - Feed into cardiovascular control center

general strength training principles

Intensity - 8-12 RM Number of sets for maximal strength gains - 2+ sets result in greater strength gains and hypertrophy >10 sets not recommended for optimal strength gains Frequency - 2-4 days per week to incorporate rest days - 4-6 days per week if using "split" routines Should involve muscles used in competition Speed of muscle shortening similar to speeds used in events

light intensity physical activity , step counts, and health

LPA can be quantified by step counts. •Step counts are easily monitored with pedometers and modern wearables, including smart watches. •Generalized step count thresholds. < 5,000 = "sedentary" 5,000 to 7,900 = "low active" 7,500 to 9,000 = "active" 10,000+ = "highly active"

cool down

Return blood "pooled" in muscles to central circulation

exercise-induced improvements in vo2 max

Short duration training (~4 months); 26% increase in VO2 max - increase SV > increase a-vO2 (10% increase in SV; 2% improvement in a-vO2 ) Longer duration training (~28 months); 42% increase in VO2 max - increase a-vO2 > increase SV (15% increase in SV; 25% improvement in a-vO2)

Sum of Skinfolds to Measure Body Composition

Skinfold technique to estimate body composition. •Prediction of body density from estimation of subcutaneous fat (20 to 70% of total fat). •lower % of subcutaneous fat in women and with age. The older we get the more of our fat is going to be visceral. •Thickness of subcutaneous fat is measured. •Specific sites on the body based on age, gender, and race. •Body density is calculated using Siri equation and % percent body fat calculated from body density. •SEE = 3.5%. -inconsistencies with SF thickness (pinchability of skin) -requires experienced technician

free weights vs machines

Strength gains are similar following training using free weights and machines. •Argument for free weights: -Data exist showing that free weights produce greater strength gains -Free weights produce greater movement variability and specificity -Free weights force control of balance and stabilization •Disadvantages of free weights -Potential for injury -Proper lifting technique required -Spotters needed -Lack of variable resistance

body mass index

a measure of body weight relative to height. weight (kg) / height (m2) -no way to tell actual body composition -- a very muscular person could be classified as obese

muscular endurance

ability to make repeated contraction or sustain a contraction against a submaximal load

detraining

about 50% of the increase in mitochondrial contents was lost after one week of detraining. al of the adaptations were lost after five weeks of detraining. it took four weeks of retraining to regain the adaptations lost in the first week of detraining

genetic predisposition for endurance training and vo2 max

accounts for 40-66% vo2 max. prerequisite for vo2 max of 60 - 80 ml kg min

isokinetic

exertion of force at constant speed

dynamic or isotonic

force with movement. includes variable resistance exercise (nautilus equipment)

endurance training improves muscle antioxidant capacity

free radicals are produced by contracting skeletal muscles (can contribute to muscle fatigue). training increases endogenous antioxidants (protects against exercise-induced oxidative damage and muscle fatigue)

reversibility

gains are lost when overload is removed

specificity

training effect is specific to: -muscle fibers involved -energy system involved (aerobic vs. anaerobic) -velocity of contraction -type of contraction (eccentric, concentric, isometric)

overload

training effect occurs when a system is exercised at a level beyond which it is normally accustomed. frequency, intensity, duration

workout

training session