HSE201 Lecture Notes - Lecture 3: Triglyceride, Phosphocreatine, Anabolism
Longitudinal studies
Strength training:
- Any type of exercise training that induces adaptations of all aspects of muscle function per se, and
is not limited to adaptations associated with the muscle fibre types
- Variable results are dependent on the duration, intensity and specificity of the training
Improvements occur through a variety of adaptations:
- Neural excitation of muscle via pattern of motor unit recruitment and stimulation frequency
- Muscle architecture via altered pennation and accumulation of SR and mitochondria
- Muscle fibre hypertrophy, an increase in muscle fibre size/cross-section area/diameter, most
significant long-term component contribution to strength gains
Fibre type:
- Hypertrophy of al fibres
- General shift in fibre proportions T1 → T2a T2b/2x
Endurance training:
- Generally more well defined and consistent muscular adaptations compared with resistance
training
- Most likely due to relatively similar training load (intensity & duration)
Improvements in endurance occur through adaptations:
- Oxidative capacity via:
- Angiogenesis: increased capillary development around all fibre types
- Mitochondrial expansion: both volume and number, particularly in T1 fibres
- Fuel storage: increased glycogen content of all fibres
Muscle fibre atrophy (reduction in muscle fibre size/diameter)
- Combined with an enlarged capillary bed, serves to improve diffusion
- Thus supply of O2 and circulating fuel sources, removal of waste products (CO2+, H+, lactate)
Fibre type
- Atrophy of all fibre types
- Well defined and consistent shift in fibre proportions compared with resistance training
- General shift in fibre proportions Type 1 Type 2a Type 2b/2x
Temporal alteration of fibre type characteristics
- Occur on a temporal scale, over a time period
- 1. METABOLIC: metabolic/biochemical parameters
- ex. Development of capillaries, oxidative enzymes and mitochondrial density
- 2. ACTIVATIONAL: ultrastructures supporting activation and contractions
- ex. SR & T-system organelles
- 3. STRUCTURAL: contractile properties
- ex. MHC isoform make up of sarcomeres
3. Muscle Metabolism Overview
Components of Metabolism
- Metabolism: the sum of all the chemical reactions occurring in a living organism
- Catabolism: (degration), series of reactions by which biological molecules are broken down into
smaller molecules
- Anabolism: (formation), biosynthetic processes in which cells form molecules from smaller units,
ENERGY consuming process
- A biosynthetic processes is more expensive than the reverse degradation process is lucrative
Energy (ATP) balance
- The metabolic focus of exercise physiology is on:
- Processes that produce & consume energy within skeletal muscle during exercise/contraction
- Systemic mechanisms that support these processes
Cellular energy (ATP)
- All cellular work requires ATP
- Muscle: resting ATP ~5 mmol.l-1 exercise the same
- Well maintained via production pathways
- Even during exercise at high work rates
- Resynthesised from ADP & Pi
- Energy for resynthesis comes from catabolism of fuels: carb/trig/proteins
Catabolic energy transformation (cellular metabolism)
- Cellular energy consumption, thus energy producing pathways are highly dependent on the
characteristics of work
- Ex. In muscle: exercise: intensity/duration
- The increase in energy consumption during exercise is distributed to:
- Myosin ATPase ~70%, Ca2+ ATPase ~25%, Na+/K+ ATPase ~5%
Bioenergetics
- The chemical processes involved in the production of cellular ATP
- Muscle storage of ATP is limited, so there are 3 bioenergetic metabolic pathways
- 1. Phosphagen system: primarily encompasses cellular stores of ATP and PC, thus ATP-PC
system
- 2. Glycolysis: anaerobic breakdown of glucose or glycogen, often form lactic acid, thus Anaerobic/
Lactic Acid System
- 3. Oxidative phosphorylation: aerobic breakdown of fuels to form ATP, thus called the aerobic
system
1. The Phosphagen System
- Also occurs anaerobically
Document Summary
Any type of exercise training that induces adaptations of all aspects of muscle function per se, and is not limited to adaptations associated with the muscle fibre types. Variable results are dependent on the duration, intensity and specificity of the training. Neural excitation of muscle via pattern of motor unit recruitment and stimulation frequency. Muscle architecture via altered pennation and accumulation of sr and mitochondria. Muscle fibre hypertrophy, an increase in muscle fibre size/cross-section area/diameter, most significant long-term component contribution to strength gains. General shift in fibre proportions t1 t2a t2b/2x. Generally more well defined and consistent muscular adaptations compared with resistance training. Most likely due to relatively similar training load (intensity & duration) Angiogenesis: increased capillary development around all fibre types. Mitochondrial expansion: both volume and number, particularly in t1 fibres. Fuel storage: increased glycogen content of all fibres. Muscle fibre atrophy (reduction in muscle fibre size/diameter) Combined with an enlarged capillary bed, serves to improve diffusion.
