KINE2002: Exercise Physiology - Training Muscles to be Stronger & Exam Review
Objectives of Resistance/Strength Training
General Strength Training: Enhance fitness and health.
Weightlifting and Powerlifting Competition: Identify the strongest individual based on performance.
Bodybuilding: Aesthetic goals focusing on muscle appearance and size.
Physical Therapy: Rehabilitation to aid recovery from injuries.
Maximizing Sport Performance: Sport-specific resistance training to enhance performance in athletic endeavors.
Measurement of Muscular Strength
Standardize Instructions: Ensure consistent procedural guidance across assessments.
Predetermine Minimum Trial Number: Define a minimum number of repetitions to evaluate.
Uniformity of Warm-Up: Ensure every participant experiences a similar warm-up process.
Select Tests with High Reproducibility: Choose assessments known for producing reliable results.
Familiarization: Allow individuals to become accustomed to testing procedures.
Consistent Body Position on Test Device: Maintain a standardized position during testing.
Recognize Individual Differences: Consider variations among individuals that may impact results.
Eccentric/Concentric Strength Testing
One-Repetition Maximum (1-RM)
Initial Weight: Begin trial with a weight close to, but below, maximum capacity.
Progressive Weight Addition: Incrementally add weight in subsequent attempts until the maximum lift is achieved.
Weight Increments: Typically vary between 1 to 5 kg depending on the muscle group evaluated.
Rest Intervals: Recommended resting periods between attempts are usually 1 to 5 minutes.
Methods for Assessing Force-Generating Capacity
Bench Press Methods of Assessment
One-Repetition Maximum (1-RM): Assess maximum force exerted in a single lift.
Five-Repetition Maximum (5-RM): Measure the maximum weight that can be lifted for five repetitions.
Ten-Repetition Maximum (10-RM): Determines the maximum weight that can be lifted for ten repetitions.
Percent of Maximum:
100%, 95%, 90%, 85%, 80%, 75%, 70% corresponding to varying RMs.
Estimating 1-RM Strength Using Submax Reps to Fatigue
Formulas
For Untrained Individuals:
For Trained Individuals:
Training Muscles to be Stronger
Muscles strengthen when trained near their maximum force generating capacity.
Overload Intensity: The tension on the muscle, rather than the type of exercise, dictates overload and strength improvements.
Common Exercise Methods for Strength Training
Progressive Resistance Weight Training: Incrementally increase resistance as strength improves.
Isometric Training: Engage muscles without changing their length.
Isokinetic Training: Employ equipment that adjusts resistance according to the force exerted throughout the movement.
Strength Training Principles and Guidelines
Overload (Intensity)
Response to Overload: Muscles react more to the overload intensity than the exercise type.
Minimal Intensity for Overload: Set at 60% to 70% of 1-RM for non-fatigued muscle groups.
Approaches to Applying Muscular Overload:
Increase load (resistance).
Increase number of repetitions.
Increase speed of muscle action.
Force-Velocity and Power-Velocity Relationships
The force generated during movement is affected by the speed of muscle lengthening or shortening.
Muscle Actions:
Increasing load results in a decrease in maximum shortening velocity.
Increasing the velocity of shortening results in a decrease in force-generating capacity.
Max Force-Velocity Relationships
Optimum movement speed for each muscle group to produce maximum power is related to:
Lengthening Action and Shortening Velocity: Demonstrates the intricate relationship between force and movement velocity.
Load Repetition Relationship
The relationship between maximum repetitions to failure and load ranging from 20% to 100% of the 1-RM.
Strength Gains: Achieved when overload represents 60% to 80% of the muscle's maximum force-generating capacity.
Sex Differences in Muscular Strength
Two Methods of Approach
Absolute Muscle Strength: Total force exerted; men generally outperform women by approximately 50% in upper-body strength and 30% in leg strength.
Relative Muscle Strength: Force exerted relative to body weight, fat-free mass (FFM), or muscle cross-sectional area (MCSA).
Skeletal Muscle Fibers: Generate 16 to 30 N of maximum force per cm² of muscle cross-sectional area, regardless of gender factors.
In Vivo Force Output: Influenced by bony lever arrangement and muscular architecture.
Force vs. MCSA Plot for Elbow Flexion
Illustrates the correlation between force in Newtons and muscle cross-sectional area in cm².
Strength Training for Elderly Individuals
Evaluated peak torque of elbow flexors in older men before and after 12 weeks of training.
Evaluated changes in flexor cross-sectional area from proximal to distal ends of muscle fibers.
Strength Training for Children
Concerns regarding incomplete skeletal development preventing heavy overload.
Advised Strategy: Concentric-only muscle actions with high repetitions and low resistance for safety and effectiveness.
Guidelines for Children
Ages 5-7: Introduce basic exercises, emphasizing learning and activities without weight.
Ages 8-10: Gradually increase exercises and practice techniques.
Ages 11-13: Teach basic techniques with progressive loading of exercises; simple volume increases.
Ages 14-15: Progress to more advanced programs, emphasizing exercise techniques.
Age 16 and older: Transition into adult programs post mastery of foundational skills.
Different Strength Training Methods
Six Interrelated Methods:
Isometric Training: Engages at specific joint angles; no hypertrophy.
Dynamic Constant External Resistance Training (DCER): Maintains consistent resistance.
Variable Resistance Training: Changes resistance based on joint angle variations.
Isokinetic Training: Controls angular velocity and generates maximum force at varying speeds.
Plyometric Training: Involves explosive movements for power increase.
Circuit Resistance Training (CRT): Focuses on caloric expenditure via numerous stations.
Isometric Training
Execution Guidelines
Maximal voluntary isometric actions sustained for specific durations.
Repetitions: Should range between 5-10 repetitions per contraction.
Benefits of Isometric Training
Strength improvement occurs at various joint angles through repetitive training.
Useful in rehabilitation contexts for muscle isolation and targeted strengthening.
Limitations of Isometrics
Difficulty monitoring intensity and measuring outcomes.
Dynamic Constant External Resistance (DCER) Training
Methodology: Resistance remains unchanged during movement, engaging muscles effectively through both phases.
Key Types: Progressive Resistance Exercises (PRE) that vary in sets, reps, frequency, and intensity.
Plyometric Training
Definition: Rapid stretching followed by shortenings of muscle groups to generate powerful movements.
Basic Principle: Utilize shock absorption with arms or legs to maximize power output through rapid transitions.
Examples of Exercises: Box jumps, cone hops, hurdle hops, and long box jumps.
Circuit Resistance Training (CRT)
Structure and Guidelines
Format: 8-15 exercise stations with 15-20 repetitions each at a resistance targeted at 40-50% of 1-RM.
Rest Intervals: Limited to 15-30 seconds between stations.
Progression
Beginners: Start with light resistance and gradually increase volume by adding additional reps or repetitions through the sequence.
Practical Recommendations for Initiating Resistance Training
Avoid Max Lifts: Begin with lighter resistance and more repetitions.
Adjustment after 2-3 weeks: Reduce reps to 6-8 as strength develops.
Resistance Increase: Add more load upon achieving target reps.
Muscle Group Engagement Sequence: Order exercises from larger to smaller muscle groups to mitigate fatigue.
Mechanisms of Strength Gain
Influencing Factors: Genetics, nervous system activation, nutritional status, muscle mass, endocrine influences, environmental factors.
Strength Training - Neural Adaptations
CNS Enhancements
Three central nervous system factors contributing to neural adaptations:
Increased CNS activation.
Improved motor unit synchronization.
Decreased neural inhibitory reflexes.
Strength Training – Muscle Adaptations
Key Factors
Muscle cross-section size.
Fiber type composition.
Mechanical arrangement of muscle and bone.
Hypertrophy Explained
Definition: The increase in muscle fiber size due to:
Enhanced contractile proteins.
Increased number and size of myofibrils per fiber.
Growth of connective, tendinous, and ligamentous tissues.
Increased essential enzymes and nutrients.
Strength Training Adaptations Overview
Neural Adaptations: Dominate early training phases, laying the groundwork for long-term progress.
Hypertrophy-Driven Adaptations: Offer an upper limit for training improvements long-term.
Cellular Adaptations from Resistance Training
Changes in Muscle Fibers
Number, Size, and Type: Vary significantly across different training modalities.
Capillary Density: Increased in bodybuilders; effects in powerlifters vary.
Mitochondria Volume: Responses are equivocal regarding volume and metabolic adaptations.
Other Adaptations
Connective tissues (ligaments, tendons, etc.) strengthen in response to muscle hypertrophy and strength increases, providing joint protection and enhancing rehabilitation strategies.
Muscle Remodeling Processes
Fiber Type Changes: Possible to shift type proportions within 4 to 8 weeks of strength training, typically increasing Type IIa fibers while decreasing Type IIb fibers.
Muscle Fiber Hyperplasia
Definition: Development of new muscle fibers through the activation of dormant satellite cells or longitudinal splitting of existing fibers.
Adaptations of Connective Tissue and Bone
Response to Increasing Strength: Strengthening of ligaments, tendons, and bone tissues coinciding with muscle hypertrophy, supporting injury prevention tactics.
Body Composition Adaptations to Strength Training
Minimal decreases in body fat coupled with increases in total body mass and fat-free mass observed, with no superior results for specific training programs.
Delayed Onset Muscle Soreness (DOMS)
Occurs 24-48 hours post-exercise and can last up to 7 days, especially after unaccustomed activities.
Factors Contributing to DOMS
Minute muscle tissue tears or damage.
Osmotic pressure disruptions.
Muscle spasms.
Overstretching and impact on connective tissue.
Acute inflammation.
Altered calcium regulation within cells.
Six-Phase Sequence for DOMS Development
Begins with unaccustomed exercise involving eccentric actions, leading to muscle damage and inflammation that ultimately promotes future resilience in the exercised fibers.
Questions?
Open floor for discussion and further inquiries related to content covered in the training or examination topics.