Speed

Speed and Related Concepts

Definition of Speed

• Speed is defined as the ability to achieve high maximum velocities.

• It is a scalar quantity representing the rate of movement, as opposed to velocity, which is a vector quantity indicating both speed and direction.

Components of Speed

• Linear Speed: Involves movement in a straight path.

• Multidirectional Speed: Involves movement in multiple directions.

• Change of Direction (COD): Refers to the ability to change movement direction explosively, affecting both velocity and speed.

• Agility: Combines skills and abilities needed for COD, velocity adjustment, and reaction to stimuli.

Physical Principles of Speed

Speed Formation

• Speed can be viewed as a combination of:

  • Acceleration

  • High maximum velocity

• Change of Direction is composed of:

  • Deceleration

  • Change of Direction (COD)

  • Acceleration

• Agility consists of:

  • COD

  • Perceptual cognitive ability

• Performance attributes:

  • Physical capacity

  • Technical proficiency

  • Biomechanical efficiency

  • Metabolic efficiency

Force Production in Athletics

Fundamentals of Force

• Athletes must apply force against external and internal resistance, with limited time to do so during athletic activities.

• Rate of Force Development (RFD): This indicates how quickly maximal force can be developed and is crucial for explosive strength.

• Impulse: Defined as the product of force and time, visualized as the area under a force-time curve and affecting changes in momentum.

Impulse and Momentum

• Impulse dictates the magnitude of change in momentum.

• Adequate force must be maintained during moments of acceleration or deceleration for optimal performance.

Acceleration Dynamics

Acceleration and Deceleration

• Acceleration: Transition from lower to higher velocities (positive acceleration).

• Deceleration: Transition from higher to lower velocities (negative acceleration).

• RFD is crucial for measuring an athlete’s explosive abilities, with maximal contraction force requiring over 300 ms.

• To achieve higher acceleration, greater force output must occur rapidly.

Ground Reaction Forces

Ground Contact Phases

• The ground contact time fluctuates between different phases of running. For instance:

  • Maximum velocity phase shows shorter ground contact times compared to acceleration phase due to high RFD.

• Understanding the relationship between vertical and horizontal forces is vital for optimizing sprinting techniques.

Practical Implications of Speed, COD, and Agility

Speed Development Over Time

• Power can be empirically expressed as:

  • Power = Force x Velocity

• Key factors influencing speed, such as impulse, must be developed through specific training.

• Distinct training modalities target aspects such as acceleration and agility, considering cognitive elements.

Neurological Influence on Speed

Nervous System Factors

• The nervous system significantly impacts muscle contraction rates and strengths.

• Strength training enhances neural drive, improving force production capacity and RFD.

• Plyometric training also boosts the rate of neural activation and enhances impulse generation capabilities.

Training for Speed: Stretch-Shortening Cycle (SSC)

SSC Explanation

• The SSC involves an eccentric-concentric coupling where muscles are rapidly stretched and then contracted.

• Key to improving explosive movements like running and jumping through enhanced elastic energy recovery.

Training Considerations for SSC

• Activities should promote skillful, multijoint movements and be structured to maintain fatigue management.

• Incorporating progressive plyometrics with heavy resistance training is vital.

SMM Preactivation and Training

Understanding SMM and Stride Mechanics

• Preactivation enhances the sensitivity of muscle spindles, improving the rate of force application and muscle efficiency.

• Elite sprinters display a different force production technique compared to non-elite counterparts, emphasizing training adaptability.

Conclusion on Speed and Sprint Dynamics

Sprint Technique and Performance

• Key performance metrics include ground contact time, stride length, and stride frequency.

• Elite sprinters excel in achieving higher velocities due to optimized biomechanics and application of forces during ground contact.

• A well-structured training regimen emphasizing sprint mechanics, endurance, and muscle memory will yield optimal speed improvements.

Future Training Focus

• Training methods should converge on enhancing RFD and impulse through specific exercises like explosive weightlifting and sprint training, ensuring optimal stride length and frequency.