Energy metabolism is a series of chemical reactions that result in the breakdown of foodstuffs (carbohydrate, fat, protein) by which energy is produced, used, and given off as heat. Roughly, the body is about 20 percent efficient at trapping energy released. About 80 percent is released as heat, which explains why your body heats up quickly when you exercise. A closer look at muscle anatomy reveals that the mode of energy storage and energy systems used is related to physical activity.
Physical activities can be classified into these four basic groups, based on the energy systems that are used to support these activities:
- Strength/power: Energy coming from immediate ATP stores. Examples include shot put, powerlift, high jump, golf swing, tennis serve, and a throw. Activities last about 0 to 3 seconds of maximal effort.
- Sustained power: Energy coming from immediate ATP and CP stores. Examples include sprints, fast breaks, football lineman. Activities last about 0 to 10 seconds of near-maximal effort.
- Anaerobic power/endurance: Energy coming from ATP, CP, and lactic acid. Examples include 200- to 400-meter dash and 100-yard swim. Activities lasting about 1 to 2 minutes.
- Aerobic endurance: Energy coming from the oxidative pathway. Activities last over 2 minutes.
In power events, which last a few seconds or less at maximal effort, the muscles depend on the immediate energy system, namely ATP and CP reserves. In speed events, the immediate and non-oxidative (glycolytic) energy sources are utilized. In endurance events, the immediate and non-oxidative energy sources are used, and the oxidative energy mechanisms become a more important source of energy. ATP and CP are replenished from energy derived from complete breakdown of glucose, fatty acids, and some proteins.
Adenosine triphosphate (ATP) is the molecule that stores energy in a form that can be used for muscle contractions. Energy production then revolves around rebuilding ATP molecules after they are broken down for energy utilization. Muscle cells store a limited amount of ATP. During exercise the body requires a constant supply of ATP in
order to provide the energy needed for muscular contraction. Therefore, to maintain a constant supply of energy, metabolic pathways must exist in the cell with the ability to produce ATP rapidly. Muscle cells can produce ATP by any one of or a combination of three metabolic pathways: the ATP/CP pathway, the glycolytic pathway, and the oxidative pathway.
ATP/CP Energy Pathway
Creatine phosphate (CP) is high-energy phosphate molecule that is stored in cells and can be used to immediately re-synthesize ATP. The ATP/CP pathway (see Figure 1.2) is anaerobic, which means it requires no oxygen for energy use. This energy pathway is demonstrated in sports that require ballistic, explosive strength or maximal effort for short periods of time, such as shot putting, pitching, weight lifting, and powerlifting.
ATP/CP pathway: ATP and CP provide anaerobic sources of phosphate-bond energy. The energy liberated from hydrolysis (splitting) of CP re-bonds ADP and Pi to form ATP.
Bible verses for today’s meditation and inspiration: Matthew E. McLaren
2 Chronicles 7:14 NKJV if My people who are called by My name will humble themselves, and pray and seek My face, and turn from their wicked ways, then I will hear from heaven, and will forgive their sin and heal their land.
Psalm 4:1 ESV Answer me when I call, O God of my righteousness! You have given me relief when I was in distress. Be gracious to me and hear my prayer!
Psalm 5:1-3 NKJV Give ear to my words, O Lord, Consider my meditation. 2 Give heed to the voice of my cry, My King and my God, For to You I will pray. 3 My voice You shall hear in the morning, O Lord; In the morning I will direct it to You, And I will look up.
Psalm 6:9 NKJV The Lord has heard my supplication; The Lord will receive my prayer.
Psalm 17:1 NKJV Hear a just cause, O Lord, Attend to my cry; Give ear to my prayer which is not from deceitful lips.
Psalm 42:8 NKJV The Lord will command His lovingkindness in the daytime, And in the night His song shall be with me— A prayer to the God of my life.
Psalm 54:2 NKJV Hear my prayer, O God; Give ear to the words of my mouth.
Psalm 55:1 NKJV Give ear to my prayer, O God, And do not hide Yourself from my supplication.
Psalm 55:17 NKJV Evening and morning and at noon I will pray, and cry aloud, And He shall hear my voice.
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