Module 4F Comprehensive Notes on Accentuated Eccentric Loading

Accentuated Eccentric Loading

Introduction

• Accentuated eccentric loading is a topic of interest in the research lab at Edith County University.
• Dylan Suarez's paper mentioned it, and Dr. Merrigan's review paper is a valuable resource.

Eccentric vs. Concentric Force Production

• Force production is higher during the eccentric phase of movement compared to the concentric phase.
• Traditional resistance training may chronically underload the eccentric phase because it uses the same load for both phases.

Eccentric Force Deficit

• Dr. Melissa Harden (Gymshark's head biomechanics person) demonstrated a 13% eccentric force deficit in the leg press.
• This means individuals can lift about 13% more eccentrically than concentrically in the leg press.
• Dr. Harden hypothesized that enhancing force in the eccentric phase would maximize training adaptation.

Research on Eccentric and Concentric Strength Differences

• Dan Hollander (2007) found a 30-46% difference between eccentric max and concentric 1RM in machine-based exercises.
• In cable machine exercises, Hollander showed about a 36% difference.
• Kelly found a 24% difference between eccentric 1RM and concentric 1RM in the bench press
• Differences between eccentric and concentric strength are exercise-specific; more technical exercises may have smaller differentials.

Augmented vs. Accentuated Eccentric Loading

• Augmented and accentuated eccentric loading are often used interchangeably but should not be.
• Augmented Eccentric Loading:
  • A programming tactic where a greater eccentric load is applied during a coupled eccentric-concentric action.
  • Eccentric load is higher than the concentric load.
  • If the eccentric load is less than the concentric 1RM, it's a submaximal accentuated eccentric load.
• Accentuated Eccentric Loading:
  • Programming tactic where eccentric load applied during the coupled eccentric-concentric action is greater than the concentric 1RM.

Terminology Clarification

• For this class:
  • Augmented: Eccentric load is greater than concentric load but less than the concentric 1RM.
  • Accentuated: Eccentric load is greater than the concentric 1RM.

Augmented Eccentric Loading: Purpose and Strategies

• Goal: Enhance the stretch-shortening cycle and stimulate the neuromuscular system.
• Mechanism: Neurological stimulation and enhanced force production capacity during the concentric phase.

Programming Strategies

• Apply augmented eccentric load on every repetition of the set (requires a cluster set paradigm). A cluster set paradigm is when we have a small inter repetition rest that would be used to reload the weight releaser so that we have the eccentric load at the higher level.
• Apply it only on the first repetition of the set.

Cluster Set Model Example

• Rest interval indicated by #.
• Descend with 80% of 1RM, stand with 40% on the concentric.
  • This enhances the stretch-shortening cycle.

Single Repetition Application

• Only apply the augmented eccentric load on the first repetition, then continue the set as normal.
• Studies show a much higher movement velocity on the repetition immediately following the augmented eccentric load.

Key Consideration

• Aim for a significant contrast between eccentric and concentric loads when targeting stretch-shortening cycle performance.

Accentuated Eccentric Loading: Purpose and Strategies

• Uses maximal or supermaximal eccentric loads.
• The eccentric load is greater than the concentric load.
• Aims to leverage higher forces generated during the eccentric muscle action to provide a unique stimulus for physiological adaptations.
• The eccentric phase is where most adaptations are stimulated.

Programming Strategies

• Cluster set paradigm.
• Application on the first repetition of each set.

Cluster Set Model Example

• Descend with 120% of 1RM, stand with 80%.
  • Aim for approximately a 40% differential between loading structures.

Single Repetition Application

• Apply to only the repetition, which again, can lead to enhanced that velocity

Application Scenarios

• Accentuated eccentrics can be applied during resistance training or plyometric exercises.

Accentuated Eccentrics in Resistance Training: Machine-Based

• Dr. Harden's leg press machine: A unique system that applies eccentric load on every repetition using compressed air and has force plates to measure force.
• She conducted a training study applying it on every rep:
  • Observed really interesting performance benefits.
  • Enhancement in traditional strength, AEL (Accentuated Eccentric Loading) strength, concentric 1RM, isometric at 90 degrees, eccentric 1RM, squat 1RM and traditional 1RM.

Accentuated Eccentrics in Resistance Training: Free Weight Model

• Weight releasers (Dr. Nick Ripley from Salford University uses this).
• Weight releasers release weight at a set point in the squat.
• Holly Shawcross (former national class weightlifter): Weights release about 10 centimeters from the bottom position in the squat.

Guidelines for Using Weight Releasers

• Athlete must have excellent squat mechanics.
• Release weight 5-10 centimeters prior to the bottom of the squat.
• Use two spotters for efficient reloading if using on every repetition.

Research on Weight Releasers and Performance

• Douglas study with rugby players:
  • Compared slow AEL with slow traditional resistance training and fast AEL with fast traditional resistance training.
  • Slow AEL benefited maximal strength and maximal velocity sprint variables.
  • Fast intervention: Some benefits but showed only benefits at, likely positive with the drop jump contract time and it tended to reduce peak power output.
  • Slow AEL was superior based on the loading parameters used.

Weight Releasers and Leg Press Machine

• Used at Edith Cowan University:
  • Releasing 5-10 centimeters before the bottom created a different training stimulus.
  • Improved performance, neuromuscular parameters, and muscle thickness.

Accentuated Eccentrics in Plyometrics

• Dumbbell release vertical jumps onto a box.
• Release 20-30% of body mass before jumping.
• Advanced option: Quarter squats from a pin with 120-130% of 1RM, followed by a box jump.

Programming Considerations for AEL

• Strategies depend on targeted training outcomes and should align with the global periodization plan.

Three Basic Strategies

• Eccentric load must be greater than the concentric load.
• Exercise must involve a coupled eccentric and concentric muscle action.
• Minimize interruption between the eccentric and concentric phases.

Submaximal AEL (Augmented)

• For individuals who bench less than 1.5 times body mass or squat less than 2 times body weight.
• Use body mass with a 20-30% eccentric load applied via dumbbells or kettlebells, transitioning into a jumping task.

Augmented and Accentuated Eccentric with Loaded Activity

• Submaximal (Augmented):
  • Concentric load: 30-50% of 1RM.
  • Eccentric load: 60-90% of 1RM.
  • Apply with weight releasers on bench throw, back squat, front squat, bench press, or leg press.
• Accentuated:
  • For stronger individuals (bench above 1.5 times body mass or back squat greater than 2 times body mass).
  • Maximal eccentric: 100% load for eccentric, 30-80% on the concentric load with weight releasers.
  • Supermaximal: Up to 120% on the eccentric load, 30-90% on the concentric load with a weight releaser.

Determining Loading

• Testing an eccentric 1RM is time-consuming and hard to judge.
• Predicting based off of the 1RM is important.
• It's not always practical and has a high injury potential and predict eccentric one, one REM from literature, but it's just an estimate, probably it's best to use a percentage of the concentric one RM.

Programming Strategy: Maximal AEL Example

• Best squat: 205 kg.
• Eccentric 1RM: 256 kg.
• Target: 80% of each load.

Calculations

• Total load eccentrically: $205 \text{kg}$
• 80% of concentric: $164 \text{kg}$
• Bar weight: $20 \text{kg}$
• Load on the bar: $144 \text{kg}$
• Load on weight releasers: $61 \text{kg}$ total or $30.5 \text{kg}$ per side.

Supermaximal Example

• 85% eccentric load, 75% concentric load.
• Concentric load: $218 \text{kg}$
• Load on the bar: $134 \text{kg}$
• Load on each weight releaser: $42 \text{kg}$.

Implementing AEL: General Strategies

• Cluster set is beneficial. Account for reracking and unracking time (30-40 seconds).
• Apply only on the first repetition.
• Cluster sets: Three reps with AEL on rep one, total of six repetitions.
• Continuous application if using a machine.

FiBadot's Cluster Set Strategy

• Load: 95% of 1RM
  • Minimum reps: 1
  • Maximum reps: 2
  • Rest: 15-25 seconds between repetitions
• Avg reps 3, 15-25 seconds between repetitions for a load of 90%

Programming Example

• Estimate eccentric load based on a percentage of maximum.
• Sample Program:
  • Day 1: Work up to 90%
  • Friday:Unload (drop to 70-75%)

Aligning AEL with Periodization

• General Prep Phase:
  • Tempo max AEL or submax AEL
  • Tempo augmented eccentric loading or accentuated eccentric loading.
• Maximal Strength Phase:
  • Maximal AEL or submaximal AEL
  • Augmented eccentric loading or accentuated eccentric loading.
• Specific Prep (Strength-Speed):
  • Submaximal AEL and plyometrics (complexes).
• Speed-Strength Phase:
  • Plyometrics and submaximal AEL (augmented with eccentric loading).

Conclusion

• Extra loading during the eccentric phase can enhance performance.
• Augmented is always submaximal, accentuated is maximal or supermaximal.
• Use cluster sets or apply on the repetition of a set.
• Important Note: Do not use with novice athletes who have poor movement mechanics; athletes should have a good training base.