Principles of Strengthening Exercise

Principles of Strengthening Exercise

• Strength is a crucial physical quality, most important for overcoming external weight or resistance via muscle contraction.
• Strength classifications include dynamic (acceleration, like throwing) and static (deformation, like pushing).
• Active strength includes maximum, swift, and resistance forces; reactive strength utilizes elastic components (plyometrics).
• Training one strength type may not improve others significantly.

Derived Capacities

• Endurance is the ability to maintain effort against fatigue, coming in aerobic (long, low intensity) and anaerobic (short, high intensity) forms.
• Speed is the ability to perform movements quickly, limited by neural drive and muscle contraction speed.
• Flexibility is the ability to move through the largest possible range of motion.

Effects of Strength Training

• Neural adaptations improve neural recruitment, CNS activation, motor unit synchronization, and inhibit reflexes (Golgi tendon organs).
• Muscular adaptations (hypertrophy) result in increased myofibrils, actin-myosin myofilaments, sarcoplasm, and connective tissue (though rapid growth can lead to muscle ruptures, sometimes needing steroids).

Muscle Atrophy

• Loss of muscle mass, particularly prominent in the first week of immobilization (3-4% loss per day, primarily affecting type 1 fibers).
• Full recovery takes longer than immobilization time; muscle memory plays a role in faster recovery from inactivity.

Static Strength (Isometric Exercise)

• Involves tension without changing muscle length.
• Training for hypertrophy uses (70-75%) maximal resistance and 3-30 second sustained contractions.
• Training for maximum strength uses (80-100%) maximal resistance and 1-5 second repetitions.

Dynamic Strength: Concentric Exercise

• Muscle force is greater than resistance.
• Strength training using repetition-based relationships for different goals.
• Intensity typically falls in the 60-85% range.
• This type of exercise offers benefits in increasing muscle strength, reducing injury risk, and providing faster exercise recovery.

Dynamic Strength: Eccentric Exercise

• Muscle force is less than resistance.
• Characterized by slow movement speeds.
• Training style involves eccentric-centric muscle movement cycles.
• Though stronger, eccentric training comes with greater injury risk.

Dynamic Strength: Isokinetic Exercise

• Resistance varies to match force applied at different points of motion during consistent speed.
• This method offers joint-control benefits but typically entails more expensive equipment and lab-like settings.

Efforts of Short Duration & Maximum Strength

• These efforts rely on ATP and phosphocreatine (PC) for energy.
• Muscles have limited ATP and PC stores, depleting quickly.
• Activities such as weightlifting use these energy sources.

Efforts of Short Duration & High Intensity

• These efforts depend on glucose (glycogen form) and anaerobic glycolysis.
• Lactic acid production is an outcome of these efforts, and with insufficient oxygen, Krebs cycle fails.
• Activities like 1500-meter runs rely on these short bursts of energy.

Efforts of Long Duration

• Aerobic glycolysis is a primary energy source, also using fat oxidation.
• Limited glycogen stores play a part in longer-duration activities (ex: marathons).

Energy Sources & Resistance Types

• ATP is immediate energy, quickly used.
• Phosphocreatine (PC) facilitates ATP resynthesis, mainly for short durations (30s).
• Glucose is the main fuel for 3+ minutes exercise.
• Fat aids in longer durations (4+ hours).

Aerobic-Anaerobic Transition

• The lactic threshold is the intensity where oxygen supply reaches its limit, transitioning to anaerobic sources.
• The ventilatory threshold, related to lactic threshold, corresponds to blood changes.

Execution of Exercise

• Execution time includes eccentric (muscle lengthening) and concentric (muscle shortening) phases, and rest intervals.
• Higher maximal resistance percentage leads to fewer repetitions needed.

Execution Speed

• Maximum speed is the fastest possible movement with controlled load, while dynamic maximum force involves rapidly moving a maximum load.

Exercise Technique

• Effective exercise techniques consist of well-defined positions, grips, displacements, and breathing strategies.

Position, Grip, Displacement

• Proper posture (e.g., upright spine, arms close to body) and stances (e.g., legs hip-width apart) are fundamental.
• Efficient grips (e.g., supine, prone, neutral) match the exercise type.
• Controlled movements during exercise are crucial.

Breathing

• Active breathing involves inhaling during concentric actions and exhaling during eccentric actions (particularly in dynamic exercises with resistance).
• Passive breathing might be utilized for effort management during certain stages of exercises.

Exercise Program Design

• Program design involves determining aims (e.g., strength, endurance, power), the number of sets and repetitions per session, intervals of rest, and duration.
• Guidelines for a healthy individual’s strength-building routine might involve sets of 6-8 maximum rep ranges, with suitable rest periods according to the specific training style.