Understanding Flexibility, Strength, and Muscle Contractions

Posted on May 8, 2024 in Physical Education

Joint Mobility and Muscle Elasticity

Joint mobility refers to the range of motion each joint in your body possesses, limited by bone and cartilage structures. Muscle elasticity describes the ability of a muscle or muscle group to stretch.

The Stretch Reflex

The stretch reflex is a protective mechanism that causes a muscle to contract when it is rapidly stretched, preventing potential injury. While this reflex is crucial for preventing injuries during quick movements, it can sometimes hinder achieving deeper stretches.

Benefits of Good Flexibility

  • Reduces muscle tension and combats stress.
  • Prevents injuries.
  • Accelerates recovery processes.
  • Facilitates explosive or fast movements.
  • Improves coordination and range of motion.
  • Reduces the risk of back pain by enhancing trunk mobility.

Flexibility Training Systems

Dynamic Stretching (Rebounds)

  1. Activates the stretch reflex, making them less ideal for developing flexibility.
  2. Important for improving and maintaining elasticity of muscles and tendons.
  3. Helps increase explosive force production capacity.
  4. Should not be the sole focus of flexibility training.
  5. Can be included in cool-down routines.

Static Stretching

  1. Serves as a bridge between inactivity and activity.
  2. Keeps muscles flexible and prepared for movement.
  3. Essential in physical education, training, bodybuilding, fitness, and general physical activity.

Self-Stretching Guidelines

  1. Stretching should not cause pain.
  2. Begin with a gentle stretch for 10-30 seconds.
  3. Gradually ease into a more comfortable position.
  4. Deepen the stretch by 2-3 centimeters and hold for another 10-30 seconds.
  5. Maintain slow, controlled breathing, keeping the body relaxed and focusing on the stretch.
  6. Keep the stretched muscles as relaxed as possible.

Factors Influencing Flexibility

  • Age: Flexibility increases during childhood and adolescence, stabilizes in adulthood, and gradually declines with age.
  • Sex: Women generally exhibit greater flexibility than men due to factors such as hip and pelvis structure, hormonal regulation, lower muscle tone and mass, and societal expectations.
  • Genetics and Training Level: Genetic predisposition and training history also play a role in flexibility.

Understanding Muscle Contractions

Isometric Contraction

  1. Occurs when there is no external movement or change in joint angle.
  2. Involves postural muscles (e.g., lower back) to maintain positions.
  3. Examples include holding an object, gripping a racket, or pushing against a wall.

Concentric Contraction (Dynamic)

  1. Force generated exceeds the resistance, resulting in muscle shortening.
  2. Example: flexing the forearm during a bicep curl.

Eccentric Contraction (Dynamic)

  1. Resistance is greater than the force exerted, causing the muscle to lengthen while contracting.
  2. Example: extending the elbow during the downward phase of a bicep curl, descending stairs, and braking or changing direction in sports.
  3. Muscle soreness is common after eccentric exercise due to microscopic muscle fiber tears.

Types of Strength

  • Maximum Strength: The ability to exert maximal force through a single contraction. Important in sports requiring control or overcoming heavy resistance (e.g., weightlifting).
  • Strength-Speed (Explosive Strength or Power): The ability to overcome resistance with explosive force as quickly as possible. Crucial in “explosive” sports like jumping, throwing, sprinting, and hitting.
  • Strength-Endurance: The ability to perform numerous maximal voluntary contractions while delaying fatigue. Strength training improves muscle fibers’ oxygen utilization and fatigue resistance.

Factors Influencing Strength

  • Muscle Cross-Sectional Area: A direct relationship exists between muscle size and maximum force production.
  • Angle of Pull: Each muscle has an optimal joint angle where it generates the most force.
  • Warm-up: Warming up increases muscle contraction rate and strength.
  • Age and Sex: Men are generally stronger than women, with peak strength occurring around 25-30 years of age, followed by a gradual decline.
  • Motivation: Motivation plays a significant role in strength performance.

Strength Training Considerations

  1. Always warm up before strength exercises and cool down with stretches to prevent muscle shortening.
  2. Maintain proper joint alignment during exercises.
  3. Control movements; speed does not equate to effectiveness and increases injury risk. Stop if you experience pain.
  4. Breathe normally during exercises, exhaling during exertion.
  5. Exercise long muscles (limbs) before short muscles (around the spine) to ensure stability and safety.
  6. Alternate muscle groups to avoid overworking the same muscles consecutively.
  7. Combine strength training with flexibility exercises to prevent muscle shortening and maintain joint range of motion.
  8. Gradually increase training intensity.
  9. Master proper exercise technique to prevent injuries.