-
What are the contraction: "passive" portions? (3)
- 1. action potential initiation: acetylcholine binds, sodium FLOWS into the cell
- 2. calcium release from SR: AP reaches SR, calcium FLOWS out of SR
- 3. first powerstroke: calcium binds to troponin, myosin head binds actin, 1st powerstroke initiated
-
what are the contraction: "active" portions?
- 1. contraction continuation: ATP needed to release myosin head, to generate "ratcheting" if calcium still present (remember: calcium need to be present bec without calcium, we won't have myosin binding site exposed)
- 2. contraction termination: ATP needed to pump calcium back into SR
- 3. contraction preparation: ATP needed to pump sodium out of cell
we want to generate the gradient... most ATP used in ratchet but need ATP to maintain gradient
-
how do muscles use ATP for energy? (3)
- 1. simple: ATP --> ADP + P + energy
- 2. super simple: APPP --> APP + P + energy
- 3. complex: ATP + H2O --> ADP + P + H + energy
- - so muscles use ATP for energy through hydrolysis
- - splitting by using water... break using water...
- - use water in cytoplasm to break ATP
-
how much ATP is used by a small active muscle?
about 187 quadrillion ATP per second
-
what are sources of ATP?
- ATP stores... to regenerate ATP from ADP
- need to find ways to stick Pi back to ADP and make more ATP
- we basically put energy in the bonds when you make the molecule
- we break the bonds to release energy and use it in any process we transfer ATP to
- 1. stored ATP (0-3 seconds)
- 2. regenerate ATP from ADP:
- a. phosphagen system (PS) 3-15s
- b. an-erobic glycolyis (AnG) 15-60s
- c. aerobic glycolysis/lypolysis (AGL) 60+s
-
1st source of ATP: ATP stores 0-3 s
- simplest/quickest way to get ATP
- while resting: fatty acids being used in muscle to create ATP stores... not glucose because being used up in another system, so use a slow method to make ATP, we have time because we're resting
- while exercising: ATP stores last for about 3 seconds (ex for a 25 meter dash)
- it's a NINJA energy source... for quick movement
- why not store more ATP? high ATP triggers apoptosis (cell death)
-
2nd source of ATP: phosphagen system 3-15s
- simple/quick way to replenish ADP --> ATP
- while resting: already created max ATP stores? now create alternative source of phosphate groups... ATP + creatine --> ADP + creatine-P... sotres ~8x more creatine-P than ATP
- while exercising: already used up ATP stores? now use alternate source of phosphate groups!!!! ADP + creatine-P --> ATP + creatine (opposite rxn of while in resting)
- creatine phosphate main ATP source for ~15 seconds
- ex for weight lifters or for 100 meter dash (good for high, energetic, short performance
- basically create creatine phosphate... new source for phosphate groups
-
how does creatine help generate ATP the quick way?
- creatine is made mainly in the LIVER from diet
- then goes to BLOOD
- then goes to MUSCLE
- in muscle creatine kinase moves phosphate ion to and from creatine
-
how does creatine indicate renal function?
- creatine is used clinically to determine kidney function
- we see that some creatine-phosphate is converted to creatine that goes to blood
- this is then filtered in kidneys and released in urine
- if kidneys aren't functioning properly, creatine levels are high in serum (blood)
- this is because the kidneys aren't clearing it out
-
3rd source of ATP: anaerobic glycolysis 15-60s
- somewhat simple or quick way
- while resting: glucose is converted to glycogen (glycogen = a string of glucose)
- while exercising: after ATP stores and creatine-P are used up...
- glycogen --> glucose --> pyruvate + 2ATP --> lactate
- ATP --> ADP + P + energy
- anaerobic glycolysis is the main ATP source for ~60s
- perfect for a 200-400 meter dash
-
can you feel the burn??? where does the burn from exercise come from???
- does not come from lactic acid!!!
- it's the hydrogen ion that's released during ATP hydrolysis
- when H+ goes into circulation, we feel the burn
- lactic acid is just a small part of it
-
4th source of ATP: aerobic glycolysis and lipolysis
- complex or slow way to replenish ADP --> ATP
- basically more complex and slower but produces a lot of energy!!!
- main source of ATP after 60 seconds
- good for a 26.2 mile dash
- while resting:
- (1) glucose --> (muscle/liver) --> glycogen
- (2) fatty acids + glycerol --> (adipose) --> triglyceride
- notice, not just glycogen in muscle but also in liver
- while exercising:
- (1) glycogen --> glucose --> pyruvate + mito + O2 --> 34-36ATP!!!
- (2) triglycerides --> fatty acids + mito + O2 --> 34-36ATP!!!
- notice difference from ANA... instead of using pyruvate with 2 ATP, bring pyruvate into mitochondria and make a lot more ATP
-
hourly breakdown of aerobic glycolysis and lipolysis: what happens at the 1st hour, after 1 hour, and after 3 hours???
- FIRST HOUR: muscle glucose
- major: glucose from muscle glycogen
- minor: glucose from liver glycogen
- minor: fatty acids from lipid cells
- AFTER 1 HOUR: liver glucose and fats
- minor: glucose from muscle glycogen
- major: glucose from liver glycogen
- major: fatty acids from lipid cells
- AFTER 3 HOURS: lots fr lipids, med from liver glucose
- minor: glucose from muscle glycogen
- medium: glucose from liver glycogen
- major: fatty acids from lipid cells
- "HITTING THE WALL"
- depletion of muscle glycogen!!!
- without that, have to rely on energy demand from BLOOD sources
- slower to get the energy so you get exhausted
-
ENERGETICS SUMMARY
-
why do we get immediate muscle pain?
because of partial or full tear of muscle/tendon/ligament
-
delayed onset muscle soreness (DOMS)
- peaks around 2-3 days after the event
- NOT due to the lack of lactate or acidity
- most likely due to tears in muscle cells or connective tissue
- stimulates prostaglandins and causes inflammation and pain
-
what is the optimal rest between exercises? why?
- 48 HOURS
- highest levels of muscle growth factors
- highest gains in muscle strengths
- not efficient to exercise everyday to stimulate muscle growth... for deposition of protein
- unless your goal is to reduce calories... then it's okay to do everyday
-
FAST TWITCH (IIb) vs SLOW TWITCH (I) muscles???
- - we see different levels of muscle types for different runners
- FAST TWITCH
- - chicken breast = flying need pectoral muscles to generate that forms
- - chickens don't really fly
- - A LOT of force generated then gone (fast)
- - for power and fitness
- - why is it white? use ATP source and creatine phosphate
- - use phosphagen system and ANA system so no need for O2
- - so there's no capillaries, blood or mitochondria
- SLOW TWITCH
- - slow twitch more for endurance and stamina
- - use aerobic method - have time to make ATP while walking around
- - why red? because we use a lot of O2, need a lot of blood vessels, mito, capillaries and hemoglobin
-
ADAPTATION: what happens during continual activity or training and also during continual INactivity and NON training
- continual activity/training: muscle changes!!!
- 1. POWER (anaerobic) - for a sprinter
- - fast twitch <-- intermediate fibers (intermediate fibers are converted to fast twitch muscle fibers)
- - more glycogen reserves
- - hypertrophy, more myofibrils (hypertrophy = muscles get larger... that's why sprinters have big muscles... lots of glycogen reserves in muscles)
- 2. ENDURANCE (aerobic) - for marathon runner
- - fast twitch --> intermediate fibers (just a little bit of fiber switching)
- - increased mito, capillaries and RBCs
- - more efficient at ATP production from mito
- continual inactivity/non-training
- - reversal of above
- - get atrophy and loss of adaptations
- - if you don't use it, won't maintain it... won't put energy to maintain it
- - caused by illness, injury and other commitments like studying or laziness
-
power vs strength vs endurance???
- power: short use, anaerobic, sprinter, big weights, fast twitch (IIb)
- strength: mix use, an/aerobic, interval running, small weights
- endurance: constant use, aerobic, marathoner, "aerobics," slow twitch (I)
what's most effective for weight loss? for cross training? for interval training? STRENGTH
-
biochemical ERGOGENIC aids
- systemic substances that enhance competitive performance
- so many ineffective non pharmacy substances, except one... CAFFEINE!
- so many pharmacy related substances... which ones are effective? what's on the prohibited list is most likely effective!
- sooooo.... caffeine is an effective ergogenic drug that increases epinephrine and focus your stamina
-
#1 prohibited drugs in international competition: 2010 prohibited substance list (in/out)
- anabolic androgenic steroidsa. testosterone and related substances
- - stimulates protein synthesis to increase muscle growth
- - stimulates hematopoiesis to increase RBC production
- b. Rx uses
- - patients with atrophy due to illness or injury (bec it helps them back on their feet)
- - patients with anemia (stimulates receptors)
- - patients with hooves
- c. Side effects: altered moods, acne, alopecia, genital shrinkage
-
#2 prohibited drugs in international competition: 2010 prohibited substance list (in/out)
- peptide hormones + growth factors
- - ergogenic aid: cell growth and proliferation
- - examples:
- growth hormone
- chorionic gonadotropin + luteinizing hormone (only in females!)
- insulin
- EPO + EPO stimulators
-
#3 prohibited drugs in international competition: 2010 prohibited substance list (in/out)
- Beta-2 agonist
- - ergogenic aid: bronchodilation
- - examples: albuterol, salmeterol
-
#4 prohibited drugs in international competition: 2010 prohibited substance list (in/out)
- estrogen receptor modulators
- - ergogenic aid: counter side effects of anabolic steroids
- - examples: tamoxifen (for breast cancer) & clomiphene (for polysystic ovarian cancer)
-
#5 prohibited drugs in international competition: 2010 prohibited substance list (in/out)
- diuretics or plasma expanders
- ergogenic aid: masks drug use, weight loss
- diuretic examples: furosemide, spironolactone
- expander examples: dextran, mannitol
- diuretic = decreases amount of fluid in system, pee a lot
- plasma expander = increases the amount of fluid in system
- basically used for the same purpose... to dilute effect of substance in your system, to mask drug use by peeing it out or diluting it
-
#1 prohibited drugs in international competition: 2010 prohibited substance list (in only!!!)
- stimulants
- ergogenic aid: increase endurance, focus, stamina
- examples: amphetamine, methylphenidate, ephedrine
- commonly ADHD medications
-
#2 prohibited drugs in international competition: 2010 prohibited substance list (in only!!!)
- narcotics
- ergogenic aid: suppress pain
- examples: oxycodone, fentanyl, morphine
- suppresses pain during competition to last longer
-
#3 prohibited drugs in international competition: 2010 prohibited substance list (in only!!!)
- glucocorticosteroids
- ergogenic aid: suppress inflammation + pain
- examples: prednisone, dexamethasone, cortisol
-
#4 prohibited drugs in international competition: 2010 prohibited substance list (in only!!!)
- cannabinoids
- ergogenic aid: suppress emesis (vomiting) + pain
- examples: tetrahydrocannabinol
-
#5 prohibited drugs in international competition: 2010 prohibited substance list (in only!!!)
- beta blockers
- ergogenic aid: increases stability
- examples: atenolol, bisoprolol, metoprolol, propanolol
- prohibited for specific sports (18 total)
- basically decreases shaking from nervousness and good for sports where stability is impt
-
2004 international journal of sports medicine... analyzed 634 supplements from 215 global suppliers... laboratory accredited by international olympic committee... results???
- you can take substances and not know it!!!
- 0% stated any hormones or pro hormones as ingredients
- 15% tested positive... most had testosterone pro-hormones
- 10% tested 'murky'
- smart marketing.... don't promote that it has the products
- say it enhances but doesn't say it has prohibited substances in it
-
SARCOPENIA ("flesh-loss")
- term for age-related loss of muscle mass, strength and function
- 30-50% decrease in an/aerobic performance
- mostly due to atrophy of type IIa fibers
- also associated with decrease in:
- myoglobin (transports O2 in muscles)
- creatine-P
- satellite cells (muscle stem cells, in injury situations, might need to make more muscles)
|
|
