Cellular Currency & Anatomy
What is the specific chemical currency that muscle fibers use directly to produce contractions?
What is Adenosine Triphosphate (ATP)?
Carbohydrates from food are stored in the liver and skeletal muscles in this specific usable form.
What is Glycogen
Which two main variables dictate which energy system dominates during physical activity?
What are Intensity and Duration
What type of meal should an athlete eat 3 hours before a competition to ensure slow, sustained fuel delivery?
What are Complex Carbohydrates paired with Lean Protein
Jackson executes a 1-Rep Max Back Squat lasting 3 seconds. What immediate cellular fuel store powered this lift?
What are pre-existing stores of ATP and Phosphocreatine (PC)?
Name the fluid portion of the cell where both the ATP-PC system and Glycolysis take place
What is the Cytosol
What digested substrate form do fats take in order to enter aerobic energy production pathways?
What are Free Fatty Acids (FFAs)
During a 100-meter all-out sprint (lasting ~10 seconds), which energy system is the dominant contributor?
What is the ATP-PC (Phosphagen) system?
Why should high-fat foods be avoided 30 minutes prior to an explosive athletic performance?
What is because fat digests very slowly and takes hours to break down, potentially causing GI distress and failing to provide immediate glucose
During a rugby match, a player jogs back into position after a tackle. Which energy system and fuel source dominate this low-intensity recovery movement?
What is the Oxidative system utilizing Fats and Carbohydrates
Name the cellular organelle responsible for aerobic ATP production during long-duration activities
What is the Mitochondria
Protein must undergo this process—removing its nitrogen group—before its amino acids can be used for energy
What is Deamination
True or False: When the Oxidative system becomes dominant during a marathon, the Glycolytic system completely turns off.
What is False? (All 3 systems work simultaneously in varying proportions; they never turn off completely)
What primary combination of macronutrients should be consumed post-workout to maximize recovery and tissue repair? What will each specific macronutrient for recovery?
What are Carbohydrates (to replenish glycogen) and Protein (to repair muscle tissue)
An endurance runner "hits the wall" at mile 20 of a marathon. What specific biochemical depletion causes their pace to drop drastically?
What is the complete exhaustion of stored Muscle and Liver Glycogen, forcing the body to rely entirely on slower Fat oxidation
When energy is released for muscle contraction, ATP breaks down into which two components?
What are ADP (Adenosine Diphosphate) and Inorganic Phosphate (Pi)
Name the metabolic pathway that splits glucose or glycogen into ATP without requiring oxygen
What is Glycolysis
As exercise intensity increases from 30% VO2max to 90% VO2max, how does the body's fuel selection shift?
What is a shift from burning primarily Fats to burning primarily Carbohydrates?
15 to 30 minutes before a match, an athlete needs rapid energy. Which macronutrient subgroup is ideal here? Provide an example
What are Simple Carbohydrates / Fast Sugars (e.g., fruit, jelly, sports drink)
Why can't a 100m sprinter rely on fat oxidation during their 10-second race, even though fats yield far more total ATP?
What is because fat oxidation requires oxygen and is too slow to meet the immediate, maximal ATP demand of sprinting
Muscle cells store enough active, pre-existing ATP to power maximal effort for approximately how long?
What is 2 to 3 seconds
*After 3 seconds, Phosphocreatine (PC) kicks in to resynthesize ATP up to ~10 seconds
Explain why breaking down fats for energy yields massive amounts of ATP but cannot fuel high-intensity sprinting
What is because fat oxidation (Beta-oxidation) requires oxygen and produces ATP very slowly compared to anaerobic pathways
Name the dominant energy system used during a 400m sprint or a hard 45-second hockey shift lasting between 15 seconds and 3 minutes.
What is the Glycolytic system
Explain the primary purpose of consuming simple liquid carbohydrates during (intra-workout) extended high-intensity practice
What is to maintain circulating blood glucose levels and preserve stored muscle glycogen without slowing down digestion
A multi-sport athlete consumes only a steak and salad 1 hour before an intense 2-hour practice. Predict their metabolic performance profile during the second hour.
What is severe fatigue/deceleration, because steak (protein/fat) and salad lack fast-digesting carbohydrates needed to maintain high glycolytic flux and replenish glycogen