Exsi 420 Ch 3 Bioenergectics

Bioenergetics

the process of converting macronutrients—carbohydrates, protein, and fats, which contain chemical energy—into usable biological energy.

Catabolism

The breakdown of large molecules into smaller molecules, associated with the release of energy.

Anabolism

The synthesis of larger molecules from smaller molecules; can be accomplished using the energy released from catabolic reactions.

ATP

• Required for all muscle activity and growth

  • Limited and require a constant supply

Chem Structure of ATP

• Hydrolosis of ATP breaks terminal phosphate bond into ADP, P, H

  • ADP breakdown and release energy

Energy systems

3;

phosphagen (anaerobic) ,glycolitic (anaerobic) and oxidative(aerobic)

Phosagen system

• short-term high intenisty

• active at start of all exercise

• creatine kinase

• rapidly replinishes ATP

Law of mass action

The concentrations of reactants or
products (or both) in solution will drive the direction of the
reactions.

Glycolysis

• breakdown of carbohydates (muscle or or blood)

• end product pyruvate

Pyruvate 2 directions during glycolisis

• Convert in lactate = fast glycolosis

  • ATP synthe at faster rate but limited

• Shuttle into mitocondria= slow glycolisis

  • slow resthyn but longer duration

  • oxygen present in sufficent quanities

Formation of Lacate

• lactate not cause of fatigue

• H+ accumilation during fatigue, reduces pH, inhibits glycolitic reactions, interferes with muscle excitation-contraction coupling

• Lacate used as energy substrate or converted to glucose in liver (glucongeneis) Cori cycle

Metabolic acidosis

exercise induced decreased pH

Krebs cycle

pyruvate entering mitocondria converted to acetyl-CoA, then it can enter the Krebs cycle

Energy yeild of glycoylis

• One molecule of blood glucose- 2 ATP molecules

• One molecule blood glycogen- 3 ATP molecules

Control of glycolysis

• Stimulated by high concetration of ADP, P and slight dec in pH and AMP

• Inhibited by lower pH, ATP, CP, citrate, and free fatty acids

Lactate threshold and onset of blood lactate

• increasing reliance on anaerobic mechanisms

• LT marker of anaerbic threshold

• exercise intensity or relative intensity at which blood lacate begins an abrupt increas above basline concentration

• LT at 50-60% max O2 uptake in untrianed

• LT 70-80% in aerobically trained

• OBLA second inc lacate accuminaltion

• high intensities (blood lactate 4mmol/L)

Oxidative (aeorbic) system

• primary source of ATP at rest and low intensity

• carbohydrates and fats

• begins w glycolis prod pyruvate

• O2 pres, pruvate enters Krebs and ETC for 32-34 ATP

Glucose and glycogen oxidation

• metabolism begins with glycolis and lead to Krebs

• NADH and FADH2 trans H to ETC , w ATP produced from ADP

Fat Oxidation

• triglycerides in fat cells broken down by hormone-sensitive lipase

• fat then into blood and enter muscle fibers

• some fatty acids come from intramuscluar sources

• free fatty enter mitocondria, break down form aceyt-CoA and H+—→krebs

Protien oxidation

not sig source of energy

protien broken down into amino acids—> glucose, pyruvate or krebs—>prod ATP

Control of oxidative system

• Iso dehy stim by ADP and inhibited by ATP

• rate of Krebs reduced if NAD+ and FAD2 not avaliable to accept hydrogen

• ETC stim by ADP and inhib by ATP

Common btw fat, carbs, protien

All reduced to acetyl-CoA and enter Krebs cycle

Relationship btw energy and rate of ATP production

An inverse relationship of energy systems max rate of ATP production and total amount of ATP it is capable producing overtime

Phosphagen intensity and duration

• 0-6s

• extremely high

Phosphagen and fast glycolyis intensity and duration

• 6-30s

• very high

Fast glycolyis intesnity and duration

• 30s to 2 mins

• high

Fast glycolyis and oxidative system intensity and duration

• 2-3 min

• moderate

Oxidative intensity and duration

• >3 min

• low

Ranking of rate and capacity of ATP production

• 1= fastest/greatest

• 5= slowest least

How is energy systems ATP production determined?

• primarily intensity of muscular activity

• secondarily on duration

• no energy complete supply of energy

Creatine phosphate depletion

50-70% during first stage 5-30 seconds of high intensity exercise

Phosphagen repletion

• short period

• 3-5 minutes occurs

• 8 minutes complete resynthesis

Glycogen depletion and repletion

• depletion related to exercise intenisity

  • above 60% max O2 uptake muscle glycogen important

  • entire glycogen content can become depleted during exercise

• repletion related to carb ingestion following exercise

  • 0.7 to 30 g of carb per kilo BW every 2 hours after exercise

Low intensity, steady-state exercise metabolism

• Exercise 15 mins

• stready state reached at 75% of Vo2max

• recovery is fast

• EPOC only last a few minutes

Excess postexercise oxygen comsumption (EPOC)

oxygen uptake above resting vaules used. to restore the body to the preexercise condition

AKA oxygen debt, recovery O2

High-intensity, non-steady state exercise metabbolism

• oxygen deficit last the entirety of exercise

• 80% of max power output

• exercise 1 minute

• EPOC take hours after exercise

Rest intervals

appropriate rest intervals and exercise intensities allow for selction of specific energy systems during training for more efficent and productive regimens

Interval training

Bioenergetic adapation for efficent energy transfer; using predetermined intervals of exercise and rest periods

more training at higher intensites

Phosphagen interval training

• 90-100 max power

• 5-10s exercise time

• 1:12 or 1:20

Fast glycolysis interval training

• 75-90 max power

• 15-30s exercise time

• 1:3 to 1:5

Fast glycoylis and oxidative interval training

• 30-75 max power

• 1-3 min exercise time

• 1:3 to 1:4

Oxidative interval training

• 20-30 of max power

• > 3 min of exercise

• 1:1 to 1:3

High- Intensity interval training

• brief high intensity exercise ellict cardiopulmary, metabolic, and neuromuscular adaptations

• cummilative duration of exercise should equate several minutes above 90% of VO2max

• 1:1 work to rest

• conjuction of other training, greater stress and risk of injury

Combination training

adds aerobic endurance to anaerobic athletes (recovery relies on aerobic mechanisms) and could reduce anabolic capabilities and be counterproductive