Rate of Force Development: Training Explosive Strength and RFD

How quickly can you produce force? Rate of force development (RFD) measures this critical quality that separates good athletes from great ones. Maximum strength matters, but often it's how fast you can generate that strength that determines performance.

What Is Rate of Force Development?

Definition

Rate of force development (RFD) is how quickly you can develop force from rest or low force levels.

RFD = Change in Force ÷ Change in Time

Higher RFD means generating more force in less time.

Why RFD Matters

Ground contact times in sport:

• Sprinting: 80-100 milliseconds
• Jumping: 200-400 milliseconds
• Cutting: 200-300 milliseconds

If you can't develop force quickly, your maximum strength is irrelevant—you don't have time to use it.

RFD vs Maximum Strength

Example:

• Athlete A: Can produce 2000N max force, reaches peak in 400ms
• Athlete B: Can produce 1800N max force, reaches peak in 200ms

At 150ms (typical ground contact):

• Athlete A: ~750N (hasn't reached max yet)
• Athlete B: ~1350N (closer to max)

Athlete B performs better despite lower maximum strength.

Components of RFD

Neural Factors

Motor unit recruitment speed:

• How quickly you activate muscle fibers
• High-threshold units recruited faster with training

Rate coding:

• Frequency of motor neuron firing
• Higher frequencies = faster force production

Muscle activation timing:

• Coordination of multiple muscles
• Pre-activation before movement

Muscular Factors

Muscle fiber type:

• Type II (fast-twitch) fibers contract faster
• More Type II = higher RFD potential

Muscle-tendon stiffness:

• Stiffer systems transmit force faster
• Reduces "slack" in the system

Cross-sectional area:

• Larger muscles have higher force ceiling
• But size alone doesn't guarantee fast RFD

The Force-Velocity Relationship

Remember: Force and velocity are inversely related.

RFD training sits in the middle:

• Not maximum force (too slow)
• Not maximum velocity (too little force)
• Optimal blend for power

Phases of RFD

Early-Phase RFD (0-50ms)

Characteristics:

• First moments of contraction
• Primarily neural
• Most trainable through explosive intent

Important for:

• Rapid reactions
• Very short ground contacts
• Sprinting, agility

Late-Phase RFD (100-200ms)

Characteristics:

• Approaching peak force
• Blend of neural and muscular factors
• Related more to maximum strength

Important for:

• Jumping (longer ground contact)
• Throwing
• Heavy lifts

Testing RFD

Laboratory Methods

Force plate testing:

• Isometric mid-thigh pull
• Measures force-time curve
• Gold standard for RFD assessment

Key metrics:

• Peak RFD
• RFD at specific time points (50ms, 100ms, 200ms)
• Time to peak force

Field Tests

Vertical jump tests:

• Countermovement jump (CMJ)
• Squat jump (SJ)
• CMJ/SJ ratio indicates RFD relative to strength

Sprint tests:

• 10m sprint (acceleration)
• Flying sprints
• First-step quickness tests

The CMJ:SJ Ratio:

• Close to 1.0 = Good RFD, using strength quickly

• 1.2 = May have RFD deficit despite strength

Training to Improve RFD

Principle 1: Explosive Intent

The most important factor for RFD:

• Try to move weights explosively
• Even if the bar moves slowly (heavy), intent matters
• Maximal effort to accelerate

Every rep should have:

• Aggressive initiation
• Intent to move fast
• No slow, grinding warm-ups

Principle 2: Ballistic Training

Movements where you accelerate through the entire range:

• Jump squats
• Medicine ball throws
• Bench throws (Smith machine)
• Olympic lifts

Why ballistic training works:

• No deceleration phase
• Maximum acceleration throughout
• Directly trains RFD

Principle 3: Plyometrics

Rapid stretch-shortening cycle:

• Depth jumps
• Bounding
• Reactive agility drills
• Hurdle hops

Plyometrics develop:

• Early-phase RFD
• Reactive strength
• Neural speed

Principle 4: Heavy Strength Training

Maximum strength supports RFD:

• Higher force ceiling
• Greater late-phase RFD
• Foundation for power development

Include:

• Heavy squats, deadlifts, presses
• 85%+ 1RM work
• Progressive overload

Principle 5: Contrast/Complex Training

Pair heavy and explosive exercises:

• Heavy squat → Jump squat
• Heavy press → Explosive push-up
• Post-activation potentiation enhances RFD temporarily

Exercise Selection for RFD

Lower Body

Ballistic:

• Squat jumps
• Box jumps
• Broad jumps
• Trap bar jumps

Plyometric:

• Depth jumps
• Bounding
• Hurdle hops
• Reactive agility

Heavy strength:

• Back squat
• Front squat
• Deadlift
• Heavy lunges

Upper Body

Ballistic:

• Medicine ball throws (chest pass, overhead, rotational)
• Bench throws
• Explosive push-ups

Heavy strength:

• Bench press
• Overhead press
• Weighted pull-ups
• Rows

Olympic Lifts

Outstanding for RFD:

• Clean and snatch
• Require explosive hip extension
• High power outputs
• Train full-body coordination

Variations:

• Power clean/snatch (from hang or floor)
• Clean/snatch pulls
• Push press/jerk

Programming for RFD

Sample Weekly Structure

Day 1: Lower Body Power/Strength

• Box jumps: 4×5
• Back squat: 5×3 at 85%
• Jump squats: 3×6 at 30%
• Romanian deadlift: 3×8

Day 2: Upper Body Power/Strength

• Medicine ball chest pass: 4×6
• Bench press: 5×3 at 85%
• Explosive push-ups: 3×8
• Rows: 4×6

Day 3: Full Body Explosive

• Power clean: 5×3
• Squat jumps: 4×5
• Depth jumps: 4×4
• Medicine ball slams: 3×8

Contrast Training Session

Complex 1:

• Heavy squat: 3 reps at 87%
• Rest 3-4 minutes
• Squat jumps: 5 reps
• Rest 3 minutes
• Repeat 4 rounds

Complex 2:

• Heavy bench: 3 reps at 87%
• Rest 3-4 minutes
• Med ball chest pass: 5 reps
• Rest 3 minutes
• Repeat 4 rounds

Periodization Considerations

Build strength foundation first:

• RFD training is more effective with strength base
• Heavy training 4-8 weeks before emphasizing explosiveness

Maintain power year-round:

• Don't abandon explosive work entirely
• At least some ballistic/plyometric work always

Peak for competition:

• Reduce volume, maintain intensity
• Emphasize explosive work closer to competition

Common Mistakes

1. Slow Training Only

Heavy, grinding reps without explosive intent.

Fix: Always try to accelerate. Move weights as fast as possible, regardless of actual bar speed.

2. Light Weight Only

Thinking power = light weights moved fast.

Fix: Heavy training supports RFD. Include 80%+ work.

3. Neglecting Plyometrics

Only doing weight room work.

Fix: Include true ballistic and plyometric training for early-phase RFD.

4. Too Much Volume

Plyometrics and explosive work are neurally demanding.

Fix: Quality over quantity. Rest fully between explosive efforts.

5. Poor Exercise Order

Doing explosive work when fatigued.

Fix: Power/explosive work first when fresh. Strength work can follow.

6. No Progression

Same jumps, same throws, forever.

Fix: Progress through harder variations, added load, or reduced ground contact times.

RFD for Different Athletes

Sprinters/Jumpers

Priority: Maximum RFD, especially early-phase

Focus:

• Plyometrics (depth jumps, bounding)
• Sprint training
• Olympic lifts
• Contrast training

Team Sport Athletes

Priority: Balanced RFD and strength for repeated efforts

Focus:

• Varied plyometrics
• Agility training
• Moderate strength work
• Power endurance

Strength Athletes

Priority: Maximum strength with adequate RFD

Focus:

• Heavy compound lifts
• Some ballistic work
• Speed work (dynamic effort)
• Maintain power qualities

Key Takeaways

1. RFD = how quickly you generate force—often more important than maximum strength
2. Sport happens fast—you rarely have time to reach maximum force
3. Early-phase RFD (0-50ms) is primarily neural; late-phase relates more to strength
4. Explosive intent is critical—try to accelerate every rep
5. Ballistic training (throws, jumps) directly trains RFD
6. Plyometrics develop reactive strength and early-phase RFD
7. Heavy strength training supports RFD by raising the force ceiling
8. Contrast training combines heavy and explosive for optimal effect
9. Train RFD when fresh—it's a neural quality
10. Include year-round—don't abandon power for pure strength training

Rate of force development separates good from great in most athletic contexts. Train to produce force quickly, not just produce force period.