Eccentric Overload Squats: Do Heavier Lowering Phases Improve Power?
If you've spent any time in the strength and conditioning world, you've probably heard about accentuated eccentric loading (AEL).
The idea is simple: make the lowering phase of an exercise heavier than the lifting phase.
Advocates claim this technique can increase power output, improve bar speed, recruit more muscle fibers, and ultimately help athletes become stronger and more explosive.
But does it actually work?
A new study published in the Journal of Strength and Conditioning Research investigated whether adding a single eccentric overload repetition to the barbell back squat could improve performance in the repetitions that followed.
The results may surprise many coaches and athletes.
What Is Accentuated Eccentric Loading?
During traditional resistance training, the load is the same during both the lowering (eccentric) and lifting (concentric) portions of an exercise.
With accentuated eccentric loading, the eccentric phase is performed with a heavier load than the concentric phase.
One common way to accomplish this is through the use of weight releasers. These devices attach additional weight to the bar during the descent and automatically detach at the bottom of the movement, allowing the athlete to stand up with a lighter load.
The theory is that the heavier eccentric phase may create a potentiation effect, helping athletes produce more force and power during the repetitions that follow.
What Did The Researchers Do?
Researchers recruited 14 resistance-trained men with an average squat strength of approximately 1.4 times their body weight.
The participants completed three different squat protocols:
- Traditional Loading (TRL): 65% 1RM during both the eccentric and concentric phases
- AEL85: 85% 1RM during the first eccentric repetition, 65% 1RM during the concentric phase
- AEL100: 100% 1RM during the first eccentric repetition, 65% 1RM during the concentric phase
Each protocol consisted of three sets of five repetitions.
The researchers measured:
- Barbell velocity
- Force production
- Power output
- Perceived exertion (RPE)
The Main Finding: No Performance Boost
Despite the additional eccentric loading, researchers found no meaningful improvements in:
- Concentric velocity
- Eccentric velocity
- Power output
- Force production
In other words, adding a heavier eccentric rep at the start of the set did not make the following reps faster, more powerful, or more forceful compared to traditional squatting.
The researchers concluded that neither the 85% nor 100% eccentric overload protocols provided an acute performance advantage over traditional loading in these moderately trained lifters.
But The Workout Felt Much Harder
Although performance didn't improve, athletes definitely noticed the extra work.
Ratings of perceived exertion (RPE) increased significantly as eccentric load increased.
- Traditional Loading: 6.9/10
- AEL85: 8.0/10
- AEL100: 8.5/10
In practical terms, athletes worked harder and felt more fatigued, yet didn't produce better performance.
That's an important consideration for coaches trying to balance training stress and recovery.
Why Didn't Eccentric Overload Work?
The answer may come down to strength levels.
Previous research has shown positive effects from eccentric overload protocols, but many of those studies used stronger athletes who could squat at least twice their body weight.
In this study, participants averaged roughly 1.4 times body weight in the squat.
The researchers suggest that stronger athletes may be better able to tolerate heavier eccentric loads and take advantage of the potential potentiation effects.
It's also possible that the overload simply wasn't heavy enough.
Previous studies that demonstrated performance improvements often used supramaximal eccentric loads of 120% 1RM or greater, whereas this study used eccentric loads of 85% and 100% 1RM.
An Interesting Velocity Pattern Emerged
One of the more interesting findings involved repetition speed.
Across all three protocols, the first repetition was consistently the slowest.
Velocity increased during the second repetition, peaked during the third repetition, and gradually declined during repetitions four and five.
This suggests that athletes may naturally perform their fastest repetitions in the middle of a set rather than immediately after an eccentric overload repetition.
What Does This Mean For Athletes?
The findings don't necessarily mean eccentric overload training is useless.
Instead, they suggest that eccentric overload may not provide immediate performance benefits for every athlete.
If you're a recreational lifter or moderately trained athlete, adding eccentric overload may increase fatigue without improving bar speed or power output.
However, stronger athletes and advanced competitors may respond differently, especially when using larger eccentric overloads.
Future research will help clarify which athletes are most likely to benefit from these methods.
The Bottom Line
A new study found that adding a single eccentric overload repetition to the back squat did not improve velocity, force production, or power output in moderately trained lifters.
What it did do was significantly increase perceived effort.
For most lifters, this suggests that eccentric overload isn't a magic shortcut to becoming more explosive. While it may still have a place in advanced training programs, traditional squat training remains highly effective without the added complexity of weight releasers and eccentric overload strategies.
As always, the best training method is the one that produces measurable results while allowing you to recover and continue progressing over time.
References
- Najafi A, Nosaka K, Javidi M, et al. Acute effects of accentuated eccentric loading in comparison to traditional resistance loading on velocity and other parameters in concentric and eccentric phases in barbell back squat. Journal of Strength and Conditioning Research. 2026;40(6):629-637.
- Merrigan JJ, Tufano JJ, Falzone M, Jones MT. Effectiveness of accentuated eccentric loading: contingent on concentric load. International Journal of Sports Physiology and Performance. 2021;16:66-72.
- Wagle JP, Taber CB, Cunanan AJ, et al. Accentuated eccentric loading for training and performance: A review. Sports Medicine. 2017;47:2473-2495.
