Eccentric vs Concentric Training for Muscle and Strength: What the Research Shows

If you've ever lowered a barbell slowly during a squat or controlled a dumbbell on the way down during a curl, you've performed eccentric muscle contractions. But how does that type of training actually compare to the more familiar concentric phase — the lifting portion — when it comes to building muscle and strength? A systematic review and meta-analysis published in the British Journal of Sports Medicine took a close look at this question, and the findings offer some useful guidance for anyone designing a resistance training program.

What This Study Examined

The central question behind this research was straightforward: does eccentric resistance training produce different results than concentric resistance training when it comes to muscle strength and muscle mass in healthy adults?

To understand why this matters, it helps to define the two terms. A concentric contraction occurs when the muscle shortens under load — think of the upward phase of a bicep curl. An eccentric contraction occurs when the muscle lengthens under load — the controlled lowering phase of that same curl. Both are part of most standard resistance training exercises, but researchers wanted to know what happens when these phases are isolated and compared directly.

The study aimed to synthesize the available evidence across multiple studies, looking at whether one contraction type produces superior gains in either strength or hypertrophy.

How the Study Was Conducted

This research took the form of a systematic review with meta-analysis, which means the authors did not conduct original experiments themselves. Instead, they gathered and statistically combined data from multiple existing studies that met specific inclusion criteria.

The review focused on studies involving healthy adults who performed resistance training programs that isolated or emphasized either eccentric or concentric contractions. The researchers examined outcomes related to muscle strength — typically measured through force production or one-repetition maximum testing — and muscle mass or hypertrophy, often assessed through imaging or circumference measurements.

By pooling data across studies, the meta-analysis allowed the researchers to identify consistent trends that might not be visible in any single, smaller study. This type of analysis is considered a strong form of evidence in exercise science because it aggregates results across a wider range of participants and conditions.

Key Findings

The meta-analysis produced several notable findings that support the value of eccentric training as a training method:

• Eccentric training produced greater gains in muscle strength compared to concentric training, particularly when strength was measured eccentrically (that is, tested under the same type of contraction used in training).

• Eccentric training also showed advantages for muscle hypertrophy, with researchers observing greater increases in muscle mass compared to concentric-only training protocols.

• The results suggest that the eccentric phase of a lift carries a meaningful stimulus for both strength and size adaptations — one that may be underutilized when lifters rush through the lowering phase of an exercise.

• While concentric training did produce strength and hypertrophy improvements, the overall trend in the data favored eccentric training as the more potent stimulus across these outcomes.

It is worth noting that the findings reflect general trends across the studies reviewed, and the magnitude of differences varied across individual studies included in the analysis.

What This Means for Training

Taken together, these findings suggest that the eccentric portion of a resistance training exercise deserves deliberate attention — not just as a transition between reps, but as an active part of the training stimulus.

In practice, this might mean:

• Slowing down the lowering phase of exercises like squats, Romanian deadlifts, bench press, or rows rather than letting gravity do the work

• Incorporating tempo training, where a specific number of seconds is assigned to the eccentric phase of each rep

• Using eccentric-focused methods such as slow negatives or eccentric overload techniques when appropriate for training goals

For people focused on building muscle or improving strength, the research suggests there may be real value in not rushing through the part of the lift most people pay the least attention to. A qualified personal trainer can help you apply these principles in a way that suits your current fitness level and goals — Atlas Personal Trainings in Reno work with clients to design evidence-informed programs both in-person and online.

It is also worth understanding that most traditional resistance training includes both eccentric and concentric phases. The research here specifically examines what happens when these are compared in isolation, which is a somewhat controlled condition. Real-world training typically benefits from both.

Limitations of the Study

As with any systematic review, this study comes with limitations that are worth understanding before drawing strong conclusions:

• Variability between studies: The individual studies included in the meta-analysis likely differed in training protocols, exercise selection, participant populations, and duration. This variability can make direct comparisons more difficult.

• Healthy adult populations: The findings apply specifically to healthy adults and may not generalize to clinical populations, older adults with specific conditions, or athletes in high-performance contexts.

• Isolation of contraction types: Studies that isolate purely eccentric or purely concentric training represent somewhat artificial conditions. Most real-world training involves both phases, so the direct application of these findings requires some interpretation.

• Short study durations: Many resistance training studies are relatively short in duration, which may not capture how adaptations evolve over longer training periods.

These limitations do not invalidate the findings — they simply remind us that research results represent one piece of the broader picture.

Conclusion

The evidence reviewed in this meta-analysis suggests that eccentric training is a particularly effective stimulus for building muscle strength and mass in healthy adults, with advantages over concentric-only training observed across both outcomes. Rather than treating the lowering phase of a lift as an afterthought, intentionally engaging the eccentric portion of each rep may meaningfully improve training results.

Research like this helps inform how many coaches structure resistance training programs — emphasizing controlled movement quality, appropriate loading, and attention to often-overlooked phases of exercise. If you're looking to apply findings like these in a structured, personalized way, working with an experienced trainer is one of the most effective ways to do so. Explore the Atlas coaching team to find a trainer who can help you build a program grounded in current exercise science.

Related Articles

• Flywheel Training and Eccentric Overload

• Best Triceps Exercise for Growth: Overhead Extensions

• How Muscle Length Affects Triceps Growth and Training

Source

The effects of eccentric versus concentric resistance training on muscle strength and mass in healthy adults: a systematic review with meta-analysis. British Journal of Sports Medicine, Volume 43, Issue 8.

Research Source: The effects of eccentric versus concentric resistance training on muscle strength and mass in healthy adults: a systematic review with meta-analysis