Muscle Strength and Speed: Training Principles and Physiology

Posted on Oct 28, 2025 in Physical Education

Muscle Strength and Contraction Dynamics

Defining Strength

Strength: The ability to exert tension against resistance.

Types of Muscle Contractions

Isometric Contraction

A contraction in which no movement occurs in any joint. The muscle retains the same length (Force = Resistance).

Dynamic Contraction

A contraction that results in movement:

  1. Concentric Isotonic Contraction (F > R): If the muscle decreases length. Example: Raising the weight.
  2. Eccentric Isotonic Contraction (F < R): If the muscle lengthens. Example: Lowering the weight.

Auxotonic Contraction

A sequence combining both concentric and eccentric phases (or varying tension/length).

Categories of Force

Key Force Types

  • Strength Endurance (Force Resistance): Applying force over an extended period of time. Example: Cycling.
  • Power (Speed-Strength): Applying force in the shortest possible time. Example: Jumps, throws.
  • Maximal Strength: Applying as much force as possible to overcome the largest possible resistance. Example: Lifting heavy stones.

Factors Influencing Muscle Force

Physiological and Structural Determinants

  • Muscle Cross-Section: Force is directly proportional to the muscle’s cross-sectional area.
  • Arrangement of Fibers: Pennate (feather-shaped) dispositions are generally more contractile than longitudinal (parallel fibers).
  • Fiber Types:
    1. Red Fibers (Slow Twitch): Resilient, fatigue slowly, and have less ability to exert maximal force.
    2. White Fibers (Fast Twitch): Fast twitch, fatigue early, and have a great capacity to exert maximal force.
  • Coordination of Agonist and Antagonist Muscles: When performing movement, muscles act in pairs. The agonist produces the movement, and the antagonist must allow the movement to manifest (stretch). Example: When the agonist contracts, the antagonist is stretched.

Principles of Strength Training

Core Training Principles

  • Overload Principle: To improve strength, training must involve increasing demands:
    1. Increase the intensity (absolute improvement of strength).
    2. Increase intensity and decrease time (improves power).
    3. Increase sets and repetitions (improves strength endurance).
  • Optimal Positioning Principle: Always train the desired area from a proper position to prevent injuries.

Systems of Strength Training

Methods for Applying Resistance

  • Self-Loading (Bodyweight Training): Using one’s own body as resistance/overload.
  • External Load Training: Moving loads with artificial elements (weights, machines).
  • Partner Resistance Training (Pair Work): Utilizing a partner for resistance (e.g., dead weight, total local opposition).

Speed and Its Components

Defining Speed

Speed: The ability to perform an action in the shortest time possible.

Types of Speed

  1. Reaction Speed: The ability to produce a response to a stimulus in the shortest time possible.
  2. Movement Speed (Gestural Speed): The ability to repeat a gesture in the shortest time possible.
  3. Displacement Speed: The ability to traverse a distance in the shortest possible time.

Factors Determining Speed

Key Determinants of Athletic Speed

  1. Physiological Factors: Dependent on the percentage of fast-twitch (white) and slow-twitch (red) fibers an individual possesses.
  2. Physical Factors: Stride length, stride frequency, resistance to maintaining maximum speed, and coordination during movement.

Guidelines for Speed Training

DITRA Training Variables

The DITRA acronym outlines key training variables:

  • D – Distance to travel
  • I – Intensity
  • T – Time of recovery
  • R – Repetition
  • A – Actions to be performed during recovery

Systems of Speed Training

Training Methods by Speed Type

  • Displacement Speed Training: Series training, varying speeds (decreases, drags, etc.).
  • Reaction Speed Training: Starts/outings, reaction games.
  • Movement Speed Training (Gestural): Focusing on frequency of gesture, using lighter loads.

Nutrition Principles and Metabolism

Macronutrient Functions

  1. Carbohydrates: 4 calories per gram. Primarily caloric (energy) function.
  2. Fat: 9 calories per gram. Primarily caloric (energy) function.
  3. Protein: 4 calories per gram. Primarily plastic (structural/repair) function.

Metabolism Definitions

  • Metabolism: The set of chemical reactions in our body used to extract energy from food and renovate the body’s structure.
  • Basal Metabolic Rate (BMR): The amount of calories our body needs each day just to stay alive (maintain basic functions).

The Importance of Relaxation

Benefits of Relaxation

Relaxation techniques will help you:

  1. Become aware of your own body.
  2. Achieve greater mental concentration.
  3. Allow your body to recover after any effort.
  4. Seek psychophysical balance.