Beta-Blockers, Sodium bicarbonate, & Diuretics in Sport Flashcards

Question

Caffeine: Skeletal Muscle Ion Handling

Answer 1

-Increased Na/K ATPase activity -Increased K uptake and Na flux -This attenuates the increase in K with exercise = maintenance of membrane potential Increased force production!

Answer 2

-Increased wakefulness -Increased vigilance -Many suggest ergogenic effect due to increased alertness or improved mood

Answer 3

-Caffeine readily passes through blood-brain barrier -Rapid rise in brain/CNS after ingestion -Also increased serotonin, dopamine, acetylcholine, NE, glutamate (all inhibited by adenosine) = increased locomotor activity & neuronal firing rates

Answer 4

Caffeine = - Decreased RPE at given power output - Increased power work when RPE constant - Decreased RPE thought to be due to decreased firing thresholds of motor neurons or changes in contraction force = decreased afferent feedback from working muscles due to a) more motor unit recruitment and b) greater force/stimulus

Answer 5

Premise: Fatigue = increased serotonin in brain due to increases in tryptophan (S precursor) However: Caffeine increased S, and Caffeine pre-exercise = increased plasma FFA, which should increase TRP In summary, results not clear at this time

Answer 6

Yes! But only at a certain urinary concentration NCAA: urinary concentration > 15 ug/mL Equivalent to ~8 cups of coffee in 2-3 hours IOC/USDA/WADA: Caffeine not prohibited??? Taken off list in 2004, now it is “restricted/controlled” Still monitoring in testing (>12ug/ml)

Answer 7

-Optimal dose for PE = 3-6 mg/kg -Thus, lower than banned/restricted limits -Only 0.5-3% ingested caffeine reaches the urine! -Majority metabolized by liver and excreted in forms not measured by doping tests -Half life? Time of test? -Habitual use? -Those that “use” caffeine regularly have dampened response

Answer 8

High CHO diet negates FFA increases due to caffeine

Answer 9

-Large research base, with general agreement -Supports increased focus and memory -Promotes musculoskeletal health in older adults -Encourages healthy blood sugar levels

Answer 10

Creatine is a nitrogenous amino acid both endogenously synthesized and consumed in the diet -Synthesized primarily in the pancreas and liver -Absorption occurs in the intestine, and is actively transported into the blood stream -Most creatine is stored in skeletal muscle (~95%), ~70% of which is found inside the cell as phosphocreatine (PCr) -PCr + ADP + H^+ -Cr + ATP -Mechanism not entirely clear -Most consider creatine/PCr as “phosphate shuttle” between cytosol and mitochondria -Some evidence of a buffering effect of PCr -PCr is a major source of skeletal muscle energy during short term high intensity bouts lasting from ~2-30 secs

Answer 11

Cr degradation rate is ~1.6% (2g)/day Thus, to maintain normal stores, it is necessary to synthesize ~2g Cr per day ~50% is achieved via nutritional intake Remainder is synthesized endogenously

Answer 12

Meat, fish, and other animal products

Answer 13

-Commercially available in powder, gel, tablet, liquid, and gum forms -Most recommendations from the literature support a dose of 20-30g Cr/day for ~14 days -Typical regimen includes both a “loading phase” and a “maintenance phase” -I.e. 5-7g/dose, 4 X per day for 5-7 days, followed by a maintenance phase of ~2g/day -Uptake is enhanced when Cr taken with CH20 -Some evidence that uptake is greater in humans with low levels of TCr (Greenhaff, et al, 1994)

Answer 14

pancreas and liver

Answer 15

Short-term, high-intensity bouts (~2-30 sec)

Beta-Blockers, Sodium bicarbonate, & Diuretics in Sport Flashcards

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