Final Exam Content Flashcards
Previous claim: Resistance exercise increases muscle mass but _________ exercise does not
endurance
Previous claim: High external loads increase muscle mass but ______ do not
low loads
Previous claim: Acute changes in hormones following resistance exercise are _______ for increasing _________
important; muscle mass
Current claim: Endurance exercise can
coexist with strength training
Current claim: Slow walking combined with _____ can increase muscle mass
BFR
Current claim: Low loads increase muscle mass similar to
high loads
Current claim: Acute changes in hormones following resistance exercise _____ appear to change muscle mass
do not
What % of 1 RM grows muscle
30 & 80
80% 1 RM for how many reps results in an increase in strength adaptation
1 & 3
Testosterone begins to decrease after ______ in the high hormone group
15 minutes
Which is better for growing muscle, high or low hormones?
Same effect
Results: Work-induced growth of skeletal muscle in normal and hypophysectomized rats
Growth evident within 24 hours
Growth reached maximal extent by 5 days
Support conclusion that pituitary growth hormone is not essential for skeletal muscle hypertrophy
Two types of muscle growth distinguished: GH-dependent, work-induced
Local mechanism of hypertrophy
calcium kinetics (specifically in heart for skeletal muscle)
Periodization definition
an exercise system, if design correctly, that helps to prevent overtraining while optimizing peak performance through progressive cycles
During periodization, as intensity increases, reps _____
decrease
Undulating Perioidzation
where volume and intensity go up and down weekly or daily within the training period
Amino acid transport across the cell increases
MPS
Results: the effects of supraphysiologic doses of testosterone on muscle size and strength in normal men
No exercise grp similar during baseline, by 10 weeks testosterone grp had effectiveness
Exercise groups had high increases in testosterone without supplementation, by 10 weeks testosterone supplementation group had effectiveness
Testosterone increased BW
Exercise increased FFM
Exercise + Testosterone significant in all CSA and weight lifted; most robust
Growth hormone lowers
glucose utilization and glycogen synthesis
Growth hormone increases _____ and enhances ______
amino acid transport across cells, fatty acid breakdown, collagen growth, and cartilage growth; immune cell function
Collagen growth increases
protein synthesis
Results: Hormonal and growth factor responses to heavy resistance exercise protocols
10 RM group had more growth due to being in the hypertrophy range
Growth hormone in 10 RM group was high showing growth hormone has anabolic properties
Results: Muscular adaptations to combinations of high and low intensity resistance exercises
Hypertrophy group had the highest growth hormone concentration
Point of diminishing returns during strength phase
MVC testing good for strength due to specificity
If the acute hormone hypothesis is true, which group in the ** Muscular adaptations to combinations of high and low intensity resistance exercises ** study would have more of an increases in muscle hypertrophy?
combo group more than strength group; hypertrophy should be minimal in strength group due to low amounts of circulating hormones
Results: Resistance exercise-induced increases in putative anabolic hormones do not enhance muscle protein synthesis or intracellular signaling in young men
Large increase in growth hormone, testosterone, cortisol, etc.
No difference in MPS which suggests hormones may not play a large role in hypertrophy
Results: Elevations in ostensibly anabolic hormones with resistance exercise enhance neither training-induced muscle hypertrophy nor strength of the elbow flexors
T1, T2, and EF CSA increase with no difference in conditions
Convinced hormones were not important for strength
Results: Associations of exercise-induced hormone profiles and gains in strength and hypertrophy in a large cohort after weight training
Growth hormone no significant relationship with LBM
Free testosterone no greater changes in LBM
IGF1 has no relationship with LBM
Cortisol only correlation to LBM (8%)
Results: Does the muscle action duration induce different regional muscle hypertrophy in matched resistance training
Quads showed significant main effect for group and muscle region
Quads CSA @ 70% had greater increase
@ 50%, 5c1e and 1c5e had higher increases in CSA
Idea for Previous RT Volume Influencing Adaptive Reponses
Previous training history sets what stimulus is necessary to induce an anabolic response in the muscle tissue
Is 4 sets to failure maximal?
3-5 is optimal
If you habitually perform 8 sets to failure, is 4 sets no longer effective?
Those who habitual do 4, do not gain anything from doing extra sets; can also be harmful to connective tissue
Muscle Hypertrophy Response Is affected by Previous Resistance Training Volume in Trained Individuals suggested
proper manipulation of RT variables can optimize muscle hypertrophic response
Results of Muscle Hypertrophy Response Is affected by Previous Resistance Training Volume in Trained Individuals study
individualized protocol significantly higher in changes of vastus lateralis
Results for Crescent pyramid and drop-set systems study
improved muscle CSA for all, between subject variability lower, crescent and drop-sets did not promote greater strength gains
Weight in hand sensed by fibers to move said weight
mechanical tension
Idea that lower loads align more metabolites for growth
metabolic stress
Metabolic Stress mechanisms
feel the burn, getting a pump, higher reps, shorter rest
Muscle Damage mechanisms
eccentrics, full ROM, novelty
Mechanical Tension mechanisms
progressive overload (system force production) & mind-muscle connection (muscle force production)
Base of hypertrophy period
mechanical tension
What contributes to fatigue?
Metabolites
Motor unit fatigue
one after the other until the complete end of the set for overall growth
Studies didn’t give opportunity for growth beyond what is maximal due to
BFR and high load RT
End product of glycolysis
lactate
ATP Hydrolysis
ATP + H2O <– ATPase –> ADP + Pi + H
Post-exercise BFR study results
cuff attenuated growth, metabolites did nothing, more discomfort in cuff group
Anabolic benefits of venous BFR study suggested that
swelling could be anabolic
Elevated plasma lactate levels via exogenous lactate infusion study results
muscle lactate and pH had drastic increases in the muscle; no difference in lactate or saline conditions
Exercise –>
mTor
mTor –>
S6K1
S6K1 –>
increases MPS
Elevated plasma lactate levels via exogenous lactate infusion study discussion
Maybe needs to be refined, or more, or injected directly into muscle; may reduce exercise while increasing lactate to see if there is a response
Characteristics of skeletal muscle
multinucleated, has mitochondria, transverse tubules (t-tubules), myofibrils, sarcomeres, intracellular structures (sarcolemma, sarcoplasm, sarcoplasmic reticulum)
Epimysium
surrounds entire muscle
Perimysium
middle; surround bundles of muscle fibers
Endomysium
surrounds individual muscle fibers
Satellite cells help with
regenerative cell growth
Through donation of what do muscle fibers continue to grow
nuclei
Structures that give skeletal and cardiac muscle their striated appearance
myofibrils
Troponin pulls away when
calcium attaches to it
Myofibrils inside
endomysium with tails pointed towards center of sarcomere
Myosin
thick
Actin
thin
Skeletal Muscle Mass
75% water, 20% protein, 5% other
Extensive branching of blood vessels ensures each muscle fiber an
adequate oxygenated blood supply from the arterial and rapid removal of CO2 in venous circulation
Enhanced capillary microcirculation expedites removal of
heat and metabolic byproducts from active tissues in addition to facilitating delivery of oxygen, nutrients, and hormones
Capillary to fiber ratio
fibers grow more than added capillaries; ratio decreases
All motor units within a muscle are considered a
motor pool
Action potential ________ the nerve terminal
depolarizes
Depolarization of the nerve terminal activates
voltage-gated calcium channels
Calcium enters the synaptic terminal and increases
cytosolic calcium concentration
Increased cytosolic calcium causes release of
neurotransmitter from vesicles
Neurotransmitter enters into __________ _________ through ____________
synaptic cleft; exocytosis
Neurotransmitter dissociates from receptor and is removed from synpase by (3)
metabolism, reuptake into nerve terminal, or diffusion away from synapse
Postsynaptic receptor
nicotinic-cholinergic receptor (NAChR)
What is nicotinic-cholinergic receptor (NAChR)?
a ligand-gated channel
Nicotinic-cholinergic receptor (NAChR) is selective for
Na and K
Activation of nicotinic-cholinergic receptor (NAChR) allows
diffusion of sodium into the cell and potassium out of the cell
Acetylcholine esterase (AChE) is localized in
folds of the endplate
Acetylcholine esterase (AChE) hydrolyses the Ach to
choline and acetate
What is taken back into the nerve terminal by sodium dependent co-transporter
choline
Choline taken back into the nerve terminal is used to
synthesize new AcH
What diffuses away from the synaptic cleft
acetate
Endplate is/is not electrically excitable
is not
The membrane surrounding the endplate is/is not electrically excitable
is
Membrane surrounding the endplate contains
voltage-gated sodium and potassium channels
Current produced by EPP spread to surrounding muscle membrane and ________ it to _________
depolarized; threshold
Current activates ________________ __________ __________ and produces an
voltage-gated sodium channels; action potential
Activation of what channels allows calcium to flow out of the SR into cytoplasm
Ca release channels
What is in the SR membrane that pumps cytosolic calcium into the SR
Ca ATPase
Action potentials travel down sarcolemma from endplate into the ____________ and activate ___________ __________ ____________
t-tubules; voltage-gated calcium channels
Activation of calcium release channels causes release of
calcium from lateral sacs of SR
Sequestration of calcium into the SR decrease
cytosolic calcium concentrations
Calcium binds to
troponin
Calcium binds to
troponin
Troponin removes blocking action of
tropomyosin
One cross-bridge cycling ceases, the sarcomere
extends to resting length
If no ATP available for cross-bridge, it remains
attached to actin producing rigor mortis
Protein that intertwines with actin and covers myosin binding sites on actin
tropomyosin
protein binds to tropomyosin and holds it over myosin binding site
Troponin
Endoplasmic reticulum-like organelles that store calcium in skeletal muscle (and cardiac) muscle fibers
SR
Enlargements at the end of SR and is associated with the transverse tubule
lateral sacs
Invaginations of the muscle plasma membrane (sarcolemma)
transverse tubules (t-tubules)
Activation of motor neuron cell body leads to
an action potential
Action potential at nerve terminal of motor neurons causes release of
acetylcholine at neuromuscular junction
Acetylcholine activates
nicotinic receptors in endplate
Activation of nicotinic receptors produces a
end-plate potential
End-plate potential depolarizes the ____________ ___________ ___________ and produces an _________ ______________
surrounding muscle membrane; action potential
Action potential enters t-tubule and activates
voltage-gated calcium channels (DHP receptors)
The plateau and descending limb of the isometric/concentric force-length relationship are well predicted and explained by the amount of
overlap between actin and myosin filaments
When muscle is stretched while activated and held at a final length long enough for force transients to cease, steady force achieved is higher than steady force developed when muscle is activated while already held isometrically at same final length
Residual Force Enhancement
Force enhancement after active muscle stretching was maintained when muscles were deactivated
Passive Force Enhancement
Force enhancement has a passive component and part of that passive components originates in the
molecular spring titin
Titin extends from
sarcomere’s z-disc to m-band
Titin runs freely in the
I-band
Titin’s extensibility provdes sarcomeres with
passive force
Passive force from titin is thought to
maintain thick filaments during contraction and provide stability and uniformity to adjacent sarcomeres
Stretching myofibrils within physiological limits results in
higher passive forces in presence of physiological levels of calcium
Deactivation of actively stretched myofibrils at an average sarcomere length of 5.0 um resulted in
no change in force
Titin forces increase when actin-myosin force
decrease
The long axis of a muscle determines the
arrangement of individual fibers
Fibers run parallel to muscle’s long axis and taper at tendinous attachment
fusiform
Fan-shaped fiber’s fasciculi lie obliquely
pennate
Fusiform’s fiber length and fiber force generation transmits directly to
tendon
Fusiform fiber arrangement facilitates
rapid muscle shortening
In fusiform, what are equal
physiological or anatomical
In pennate, physiological contains
all fibers
Total cross-sectional areas of all fibers within a particular muscle
Physiologic Cross Sectional Area
Muscles with greater pennation are slower in _______ _________, and generate greater _________ and __________
contractile velocity; force and power
Series-fibered muscle features
individual fibers that run parallel to muscle’s line of pull
Complex parallel arrangement features
muscle fibers that terminate in muscle’s midbelly and taper to interact with connective tissue matrix or adjacent fibers
Contraction under conditions in which it develops tension but does not change length
isometric
Contraction in which muscle changes length while load on muscle remains constant
isotonic
Contraction of muscle fiber in response to a single action potential
twitch
Keep length constant and measure tension
isometric twitch
Keep load constant and measure muscle length
isotonic twitch
Following action potential, an interval of a few ms known as latent period before tension of muscle fiber begins to increase
latency
The latent period is longer in which twitch
isotonic twitch
Isotonic twitch experiment, the latent period includes both time for ________________________ and extra time to accumulate enough _______________ _________________
excitation-contraction coupling; attached cross-bridges
At heavier loads
latent period is longer, velocity of shortening is slower, duration of twitch is shorter, distance shortened is less
Zero velocity at
maximum load
Unloaded shortening velocity is determined by rate at which
individual cross-bridges undergo cyclical activity
The rate of ATP splitting determines
shortening velocity
Unfused Tetanus
oscillating summated tension
Fused Tetanus
sustained summated tension
At very short lengths, the z-lines collide with ends of relatively rigid thick filaments, creating an
internal resistance to sarcomere shortening
Muscles normally operate at plus/minus what % of optimal muscle length
30%
Energy is stored between
2nd and 3rd phosphate groups
Energy systems in the cytoplasm
ATP-PCr and Glycolytic
Glycolytic energy system breaks down
CHO
CHO broken down by the glycolytic system is stored
in the muscle or glucose delivered to the blood
CHO broken down by the glycolytic system is used to
resynthesize ATP
Energy system in the mitochondria
oxidative metabolism
Oxidative Metabolism includes
KC and ETC
Oxidative Metabolism forms ATP from
breakdown of fatty acids using oxygen in the mitochondria
Enzyme to break apart PCr
creatine kinase
Creatine kinase is highest in which fibers
T2b > T2a > T1
How much ATP does the body store at any given time
80-100 g
ATP is stored in
muscle on myosin head
ATP concentrations during experimentally induced muscle fatigue
only slightly decrease (50-60% of pre-exercise levels)
AMP is a
powerful stimulant of glycolysis
AMP helps to breakdown more
CHO
How is the ATP-PCr controlled
law of mass action
Buildup of ADP will increase rate of
creatine kinase and adenylate kinase reactions
Contribution of phosphocreatine and aerobic metabolism to energy supply study results
power output less on second trial, energy supply increased during trial 2
Formation of lactate is catalyzed by
lactate dehydrogenase (LDH)
Resting blood lactate
.5 to 2.2 mmol/L
Exercise blood lactate
25 to 30 mmol/L
Rate of production of lactate higher in which type of muscle fibers
T2
Lactate is used
intermediately, exchanged between different tissues, source of carbon for oxidation, and gluconeogenesis
Lactate used in
cori cycle, cell to cell La shuttle, intracellular La shuttle
La transported across mitochondria membrane by
MTC1
Cori cycle is shuttling of
lactate to liver to form glucose
Blood lactate concentrations reflect
lactate production and clearance
Normal blood lactate levels return within
1-hour postexercise
Blood lactate accumulation is greatest following
high-intensity intermittent exercise
Glycolysis leads to
KC
Pyruvate that enters mitochondria is converted to
acetyl-coa
One acetyl-CoA is formed it enters the
KC
NADH enters the
ETC to help resynthesize ATP
Where does malate-aspartate shuttle predominate
heart
Where does glycerol-phosphate shuttle predominate
skeletal muscle
Relationship between given energy system max rate of ATP production and total amount of ATP capable to be produced over a long period of time
Inverse
Which system has the highest rate of ATP production
phosphagen
Which system has the highest capacity of ATP production
oxidation of fats and proteins
Which system has the lowest capacity of ATP production
phosphagen
Phosphocreatine can decrease markedly (50-70%) during
first stage of high intensity exercise and almost eliminated as result of exercise to exhaustion
Complete phosphocreatine resynthesis can occur within
8 minutes
Grams of glycogen stored in muscle and liver
300-400; 70-100
At relative intensities above 60% of maximal oxygen uptake, muscle glycogen becomes
increasingly important energy substrate
Repletion of muscle glycogen during recovery is related to
post-exercise CHO ingestion; .7 to 3 g of CHO per kg of body weight ingested every 2 hours following exercise
Effect of oral creatine supplementation on muscle PCr
did not result in PCr content
Muscle fiber activation study results
similar depletion seen due to failure; T1 and T2 fiber glycogen depletion determined by neither load or repetition during resistance exercise performed to failure
CHO supplementation study results
deplete less glycogen when training, drink a CHO bev; glycogen isn’t limiting factor to perform testing
Low muscle glycogen concentration study results
muscle glycogen concentration higher in norm group
stimulate MPS even with low muscle glycogen available
ingestion of PROT/CHO drink enhances anabolic response
commencing training with low muscle glycogen does not impair anabolic response in early recovery period
195 minutes on average to exhaust glycogen on one leg
Results: Cellular memory mechanism aids overload hypertrophy in muscle long after an episodic exposure to anabolic steroids
fiber size decreases the same with or without anabolic steroids but nuclei remained elevated with steroids
Results: previous short-term use of testosterone propionate enhances muscle hypertrophy in wistar rats submitted to ladder-based resistance training
prostate mass in testosterone and training and training only group was heavier
testosterone and training group has larger T1, T2, and mean fCSA
All groups has higher nuclei/fiber ratio than control
Results: skeletal muscle morphology in power lifters with and without anabolic steroids
Those with steroid use had larger type 1, 2a, 2AB, and 2c fiber areas and central nuclei were higher
Results: skeletal muscle morphology in power lifters with and without anabolic steroids
Those with steroid use had larger type 1, 2a, 2AB, and 2c fiber areas and central nuclei were higher
Maximal strength and power increases of agonist muscles result from
an increase in recruitment, rate of firing, synchronization of firing, or a combination
Motor cortex activity increases when
the level of force developed increases
Many neural changes with anaerobic training take place along
descending corticospinal tracts
Corticospinal tract controls
voluntary movement (fine, isolated movemenets)
Cell body of the corticospinal tract located in
cerebral cortex (primary motor cortex)
Corticospinal tract axons descend to ______ ______ to cross _________ _______
lower medulla; spinal cord
Axons of alpha motor neurons innervate
skeletal muscle
Interruption of the corticospinal tract produces
weakness (partial damage) or paralysis (total damage)
Axons from neurons in the brainstem that form pathways that descend into the spinal cord to influence motor neurons
extrapyramidal system
Axons of most of the brainstem remain ______________ and affect _________________
uncrossed; muscles on the same side of the body
Brainstem pathway involvement
upright posture, locomotion, balance
Fast & Slow twitch fibers differ in
peak force, time to reach peak force, and ability to maintain force
Two neural mechanisms responsible for force gradations
recruitment and rate coding
Motor units recruited first with lower force capabilities
low-threshold
Rate coding
motor unit firing rate
Smaller muscles rely on; larger muscles rely on
rate coding; recruitment
An increase in EMG indicates greater
neural activation
Anaerobic Training and Electromyography (EMG) studies show
strength and power increases of up to 73%
Muscle spindles consist of
specialized musc fibers that signal length of musc and rate of change
Intrafusal fibers are innervated by
large sensory groups that transmit length info to CNS
Ends of intrafusal fibers are innervated by
small motor neurons (gamma motorneurons)
When muscle lengthens
intrafusal fibers lengthen
Lengthening of intrafusal fibers stretches ends of
sensory nerve endings
The larger the stretch
the greater the number of AP
Gamma motorneurons set
sensitivity, or gain of musc spindles
What selects muscle lengths over which the spindle will respond by changing activity in gamma motorneurons
CNS
Golgi Tendon Organ (GTO) consists of
capsule containing branches of sensory fibers that are attached to fibers of tendon
GTO innervated by
large sensory fibers that transmit tension info to CNS
GTO signal
muscle tension
Spinal Reflexes: stretch reflex
muscle lengthens, spindle stretch, activate T1a fibers, excite alpha motor neurons, contract muscle
Spinal Reflexes: tendon reflex
muscle tension increases, GTO stretch, activate T1b fibers, excite inhibitory interneuron, inhibit alpha motor neurons, muscle relaxes
Excitation of GTO from muscle leads to
reduced excitation of the muscle
Major potential sites of fatigue
excitatory input to higher motor centers, excitatory drive to lower motor neurons, motor neuron excitability, neuromuscular transmission
With maintained excitatory activation of alpha motor neuron, firing rate decreases due to
altered ionic currents
A decrease in what is a possible factor for exercise-induced central fatigue which involves muscle-brain metabolic crosstalk
brain glycogen
Plays a role in mental fatigue
brain neurotransmission
Optimal training adaptation cyclic variations
Load: high (90-95%) and low (70%)
Volume: high and low
Velocity: fast (< 1 sec) and moderate (1-2 sec) muscle action
Exercise: 3-5+ days/week
GAS Stages
Alarm: excessive soreness, temp performance decrease
Resistance: body resists stress & performance increase
Exhaustion: too much with too little recovery
Results –> GAS: Potential misapplications to resistance exercise
upon exposure to toxic levels of pharmacological agents and stimuli there is a physiological stress response which can be losely adapted to resistance exercise
Experimental Evidence Supporting Adaptation Energy Results
Giving a little bit of the drug that could kill you, before the next drug, results in no death
Alarm Phase S&C Application
muscle damage and soreness resulting from exercise
Resistance Phase S&C Application
Adaptation to exercise stimulus; represented by increased muscle size and strength
Exhaustion Phase S&C Application
Overtraining
Adaptation Energy S&C Application
managed through periodization to avoid overtraining
Linear Periodization
As volume decreases, intensity and technique/skill will increases
Undulating Periodization
Focus on different characteristics on different days but always decreasing to minimize stressors
Preparatory Period
initial period, longest, during time of year with no competitions and only limited number of sport-specific skill practices; establish base level conditioning to increase tolerance
First Transition Period
denote break between high-volume and high-intensity training
Second Transition Period
active rest; between competition and next prep season; consists of recreational activity that may not involve resistance training
Ironman
2.4 mile swim, 112 mile bike, 26.22 mile run
Ironman record
Men: 7:40:24
Women: 8:26:18
Preparation for Half-Ironman Triathlon Results
Increases in maximal oxygen consumption, maximal power output, absolute oxygen consumption, and power output at both ventilatory thresholds
Results: Overreaching and overtraining in strength sports and resistance training; a scoping review
short-term periods of overreaching achieved with high-volume or high-intensity training can lead to non-functional overreaching
chronic high-volume and/or intensity training an lead to non-functional overreaching
Functional OR
short-term decrease in performance lasting days to weeks with performance supercompensation after a period of recovery
Non-functional OR
Performance decrement observed over a period of weeks to months while full recovery is achieved
Overtrianing
long-term reduction in performance capacity observed over a period of several months
Results: Does Short-Term Near-Maximal Intensity Machine RT Induce Overtraining
1-RM performance increased throughout week, overtraining did not occur, increased sprint times in week 2, leg extension torque decreased by week 4
Results: Performance decrements with high-intensity resistance exercise overtraining
1-RM performance significantly decreased from test 1 to test 3, isokinetic and stimulated isometric muscle force significantly decreased by test 3
Seven pillars of injury prevention
use of needs analysis, monitor rapid growth, optimize dose response, use effective training modes, start early during childhood, use risk stratification, enhance adherence
Results: The Effects of Exercise for Prevention of Overuse Anterior Knee Pain
Reduction in anterior knee pain in treatment group and less new cases of injury
Results: Hamstring injury occurrence in elite soccer players after preseason strength training with eccentric overload
hamstring injury occurrence lower in training group, increases in strength and speed in training group
Results: preventive effect of eccentric training on acute hamstring injuries in men’s soccer
Less injuries in intervention group and recurrent injuries
