This chapter focuses on developing speed, change-of-direction, and agility. These terms are often used interchangeably, but they describe different physical capacities and skills because they place different biomechanical and cognitive demands on the athlete. They’re defined as follows:

• Speed: The skills and abilities needed to achieve high movement velocities.

• Change of direction: The skills and abilities required to explosively change movement direction, velocities, or modes.

• Agility: The skills and abilities needed to change direction, velocity, or mode in response to a stimulus.

Speed, agility, and change of direction

In most sports, the ability to outrun opponents is a major performance advantage. Just as important is the ability to rapidly change direction during play - whether to evade an opponent, create space, or gain a tactical advantage.

Even when an action looks like “speed,” the underlying qualities can differ. Performance may depend on acceleration, maximal velocity, and technical execution. For example:

• Linear speed is typically expressed in sprinting.

• Multidirectional speed appears in open-field play and involves changes in direction.

Generating high speeds matters in both track and field and team sports. However, track performance depends heavily on linear speed, while success in multidirectional sports often depends on changing direction quickly and efficiently in response to constantly changing situations.

Key distinctions

• Change-of-direction abilities require deceleration and reacceleration, usually in a pre-planned pattern.

• Agility adds a perceptual-cognitive element, requiring athletes to change direction in response to an external stimulus (e.g., an opponent’s movement).

• Acceleration is involved in both change-of-direction and agility, but each has unique technical and cognitive demands.

  Key point: Speed requires the ability to accelerate and reach maximal velocity, whereas agility performance relies more heavily on perceptual-cognitive skills and decision-making.

Training group	Force at 300ms	Rate of force development (RFD)	Impulse area
Untrained	Low	Low	Small
Heavy resistance-trained	Moderate	Moderate	Medium
Explosive-ballistic-trained	High	High	Large

Spring-mass model (SMM)

The Spring-Mass Model (SMM) is a mathematical framework that describes sprinting as a coordinated sequence of spring-like actions. During sprinting:

• The leg acts like a spring that compresses at foot strike and extends during push-off, propelling the athlete forward.

• The center of mass lowers during midstance, aligning with maximum spring compression.

• The model shows how elastic energy is stored and released during running, highlighting the role of muscle stiffness and tendon compliance.

• Elite sprinters often produce more vertical force during the first half of ground contact.

As stride frequency increases, muscle stiffness becomes a key feature of effective sprinting.

Additional neurophysiological considerations for change-of-direction and agility

Change-of-direction and agility require more than physical output. They also depend on neuromuscular and perceptual-cognitive factors, including:

• Eccentric strength, especially for braking and reorienting the body.

• Short ground contact times (e.g., 0.23-0.25 sec for agility vs. 0.09-0.11 sec for sprinting).

• Stretch-shortening cycle (SSC) involvement during rapid reacceleration.

• Perceptual-cognitive skills (e.g., decision-making, anticipation) to efficiently process tactical information.

Running speed

Running speed = stride length × stride frequency

Key takeaways:

• Sprinting involves repeated stride cycles: support (stance) + flight phases.

• Speed increases by improving:

  • Stride length (more ground covered per stride)

  • Stride frequency (faster turnover)

Sprint performance differences:

• Elite sprinters:

  • Stride length ~2.70 m

  • Stride rate ~4.63 steps/sec

• Novice sprinters:

  • Stride length ~2.56 m

  • Stride rate ~4.43 steps/sec

The interaction between stride length and frequency across various speeds.

Stride length comparison (elite vs. novice)

Stride rate comparison (elite vs. novice)

Sprinting technique guidelines

Sprinting consists of:

• Acceleration phase

• Maximum velocity phase

Coaches should emphasize:

• Proper ground force application

• Efficient transition between eccentric braking and concentric propulsion

• Reduced ground contact times during acceleration

Sprinting technique checklist

Start:

• Athlete should distribute balanced body weight using a set position (blocks, 3- or 4-point staggered start).

• Front lower leg angle: ~90°

• Rear lower leg angle: ~133°

• Legs generate ~905 N of force during start clearance (~0.28 s).

• Vertical velocity is highest during block clearance and the initial steps to elevate the center of gravity.

• Key cues:

  • Exit angle of front leg during block clearance: ~160°

  • First step touchdown: ~0.5 m from start line

  • Initial velocity: up to 5 m/s

Acceleration:

• Recovery leg should stay low; toes barely leave the ground.

• Elite stride rate: 5.26 steps/sec; novice: 3.45 steps/sec

• Elite stride length (first two steps): 1.13-1.15 m; novice: 1.21-1.50 m

• Shorter stride = more frequent ground contact = better horizontal velocity

• Ground time: elite ~0.123 s vs. novice ~0.223 s

• By 20 m: sprinter should be nearly upright, with the head rising at the same rate as the torso.

Maximum velocity:

• Body alignment: shoulders stacked over hips over feet

• Relaxed head/shoulders, eyes forward

• Elite top speed: ~12.55 m/s vs. novice: ~11.25 m/s

• Elite stride rate: 4.63 steps/sec; novice: 4.43 steps/sec

• Elite ground contact time: 0.087 s vs. novice: 0.101 s

Sprinting technique: flight and support phases

Flight phase

• Early:

  • Eccentric hip/knee flexion and extension = braking

• Midflight:

  • Concentric hip flexion and knee flexion

• Late:

  • Concentric hip/knee extension for ground prep

Support phase

• Early:

  • Continued concentric hip extension

  • Eccentric knee flexion + plantarflexion = shock absorption

• Late:

  • Eccentric hip flexion + concentric knee/plantarflexion = propulsion

Common sprinting technique errors

Error	Cause	Coaching recommendation
Hips too high at start	Misunderstanding crouch	Adjust foot spacing and lower into start position
Stepping out laterally	Improper force direction	Cue pushing through the ground
Short/tight arm motion	Misunderstanding swing	Teach elbow drive and trunk rotation
Neck tension	Misunderstanding head posture	Cue head in line with spine
Premature upright posture	Weak push-off or bad posture	Cue trunk alignment and drive through the ground
Overstriding	Misunderstanding force application	Teach “run in their lane” and reduce ground contact
Cycling leg action	Improper force	Emphasize vertical force; reduce open gap during stance
Transverse arm errors	Fatigue or habit	Cue sagittal plane swing and proper alignment