Metabolic Adaptations to Training and Training Approaches

Overview

  • Investigation of how metabolic systems change with prolonged training.

  • Comparison of resistance training, endurance training, and high-intensity training.

Key Changes in Metabolic Systems

  • Insulin Sensitivity

    • Increased sensitivity with training

  • Muscle Mass & Contractility

    • Enhanced performance due to increased muscle mass and improved contractility.

  • Mitochondrial Content/Quality

    • Training improves both the amount and the quality of mitochondria within muscle cells.

  • Immune Surveillance

    • Improved systemic response boosts immune function.

  • Anti-Oxidants

    • Increased production of anti-oxidants through metabolic adaptations.

  • Hormonal Adaptations

    • Changes in hormone levels that improve metabolic functions.

  • Exercise Effects on Neuroplasticity and Neurogenesis

    • Exercise stimulates the brain's ability to reorganize itself by forming new neural connections.

  • Angiogenesis

    • Formation of new blood vessels to improve oxygen delivery to muscles.

  • Healthspan Improvements

    • Enhanced duration of healthy living through improved metabolic health.

  • Fatty Acid Oxidation

    • Increased ability to oxidize fatty acids during exercise and recovery phases.

Glycolytic Enzymes and Muscle Adaptations

  • Increased Resting Activity in Plantaris Muscle

    • Leads to greater glycogen availability within the muscle tissues.

    • Key Glycolytic Enzymes:

    • Hexokinase (HK) Activity

    • Phosphofructokinase (PFK) Activity

  • Muscle Glycogen Levels

    • Data indicates varying glycogen levels (mmol/kg dry weight) under different training statuses:

    • Exhaustion: Data not specified

    • Train-Low: Data not specified

    • Untrained Rest: Data not specified

    • Trained Rest: Data not specified

    • Highly Trained & CHO Loaded: Data not specified

    • LDH Activity

    • Varies across populations, indicating differences in glycolytic capacity.

Muscle Fiber Types and Training Outcomes

  • Fiber Type Categorization

    • Type I Fibers: Increased size, better for endurance.

    • Type II Fibers: Little to no increase in size; adaptable to strength training.

  • Fiber Type Transitions

    • Possible transition from Type IIx to Type IIa.

    • Assume no transition between Type II to Type I for discussion purposes.

Training Aims and Mechanisms

  • Focus on Training for Increased Muscle Size

    • Understanding mechanisms underlying muscle hypertrophy.

  • Repetitions per Set and Strength Training

    • Volume considerations across training weeks.

ATP and Creatine Phosphate Availability

  • Greater Muscle Mass Increases ATP and PC Availability

    • Relative concentrations of ATP and PC measured in mmol/kg dry muscle:

    • Concentration details not specified in this transcript.

    • PC Resynthesis During Recovery

    • Performance recovery over time (graphical data not specified).

Capillary Supply & Mitochondrial Function

  • Capillary Density Increases

    • More capillaries increase diffusion and oxygen consumption.

  • Mitochondrial Function Enhancement

    • Larger size and increased number of mitochondria improve ATP production capacity.

Oxidative Enzymes and Lactate Threshold

  • Oxidative Enzyme Activity Increases

    • Focus on succinate dehydrogenase (SDH) and citrate synthase.

    • Results in greater oxidative ATP production and glycogen sparing.

  • Increased Lactate Threshold

    • Ability to perform at higher intensities before lactate accumulation signals fatigue.

Respiratory Exchange Ratio (RER)

  • RER Measurement Insights

    • Decreases at submaximal intensities due to greater fat utilization instead of glucose.

    • Typical values: Untrained RER ~ 0.9, trained RER ~ 0.8.

Fat Max Protocol

  • Incremental Treadmill Testing

    • Concludes when RER reaches between 0.95 and 1.0.

    • Parameters measured include VO2, VCO2, and fat oxidation.

O2 Consumption Changes

  • VO2 Metrics

    • Resting VO2 and Submaximal VO2 transitions.

    • Maximal VO2 (VO2max): Peak values reached after 12-18 months of training.

  • Performance Factors

    • Ability to sustain higher percentages of VO2max for longer durations facilitated by improved exercise economy.

Anaerobic and Aerobic Power Training

  • Sport-Specific Metabolic Systems Training

    • Tailor programs to specific energy systems:

    • Sprints: Focus on ATP-PCr system.

    • Middle Distances: Emphasize glycolytic system.

    • Long Distances: Utilize oxidative system.

High-Intensity Interval Training (HIIT)

  • HIIT Definition

    • “HIT involves repeated short-to-long bouts of rather high-intensity exercise interspersed with recovery periods” (Billat, 2001; Buchheit & Laursen, 2013).

Interval Training Considerations

  • Training Appropriateness for Various Sports

    • Choose sport-specific modes and adjust parameters:

    • Rate of exercise intervals, distance, number of repetitions, and duration of rest.

    • Frequency of training schedules per week.

Chronic Adaptations: Traditional vs. HIIT

  • Traditional Training

    • Characteristics include long, continuous sub-maximal exercise leading to increased blood volume and oxidative enzymes.

  • HIIT Focus

    • Shorter, high-intensity bursts increase capillary density and oxidative adaptations.

Exercise Interval Intensity

  • Determining Factors

    • Duration/distance or percentage of HRmax influences intensity.

    • Target intensities based on training goals for specific metabolic systems:

    • ATP-PCr: ~ 90%-98% intensity.

    • Anaerobic Glycolytic: ~ 80%-95% intensity.

    • Aerobic Oxidative: ~ 75%-85% intensity.

Distance of the Interval

  • Activity-Specific Distances

    • Distance for sprint training varies significantly based on sport requirements, e.g., 30 to 200 m for sprints.

  • Longer Distances

    • Utilized by middle-distance runners and endurance athletes.

Repetitions and Sets per Session

  • Sport-Specific Adjustments

    • Short, intense intervals generally allow for more repetitions and sets; longer intervals require fewer repetitions.

Rest Interval Duration

  • Recovery Based on Individual Factors

    • Heart Rate Recovery is essential for determining rest intervals based on age and fitness level.

Continuous Training Techniques

  • Types of Continuous Training

    • Long, slow distance (LSD) training promoting oxidative and glycolytic metabolism, including low-intensity training.

LSD Training Metrics**

  • Training zones

    • LSD typically at ~60%-80% HRmax with a focus on distance rather than speed.

    • Normalized running volume can reach up to 15-30 miles per day.

Fartlek Training Concept

  • Definition

    • Also known as speed play—varies pace amongst sprints and jogs, combining continuous and interval training.

    • Engages distance runners enriching their training experience.

Final Metabolism Activity

  • Assessing Energy Systems

    • Focus on ATP–PCr, Glycolysis, Krebs Cycle, and ETC

    • Key steps include substrates, major enzymes, and ATP yields.

    • Identification of bottlenecks and understanding how oxygen availability regulates these pathways.

  • Practical Considerations

    • Training adaptations, substrate availability, and metabolic regulation in performance contexts.