Cuộc chiến giữa pha tập luyện Concentric và Eccentric: Phương pháp nào tốt hơn cho sự phát triển cơ bắp?

Cuộc chiến giữa pha tập luyện Concentric và Eccentric: Phương pháp nào tốt hơn cho sự phát triển cơ bắp?

Bạn đã bao giờ nghĩ về các giai đoạn khác nhau của bài tập mà bạn thực hiện ở phòng gym chưa? Hãy lấy bài squat làm ví dụ. Bạn hạ thấp người xuống tư thế squat, giữ nguyên tư thế ở điểm thấp nhất, rồi bật dậy trở lại tư thế đứng; ba giai đoạn này được gọi là co cơ lệch tâm (eccentric), đẳng trương (isometric) và co cơ đồng tâm (concentric). Và nếu mục tiêu của bạn là xây dựng cơ bắp hoặc sức mạnh tại phòng gym, bạn cần hiểu rõ hơn về chúng.

Hầu hết thời gian, trọng tâm của chúng ta với tư cách là người tập gym là di chuyển trọng lượng ở mức kháng lực cao nhất – nâng tạ lên, giữ tư thế, rồi hạ tạ xuống. Tuy nhiên, việc hiểu rõ sự khác biệt giữa các pha co cơ – đặc biệt là pha đồng tâm và lệch tâm – là then chốt để tối ưu hóa quá trình phát triển cơ bắp và sức mạnh.

Pha co cơ đồng tâm (Concentric): Đây là giai đoạn mà cơ bắp co lại, ngắn lại và tạo ra lực để di chuyển trọng lượng. Ví dụ, trong bài squat, đây là giai đoạn bạn đứng dậy từ tư thế ngồi xổm. Pha này thường được chú trọng nhiều hơn bởi vì nó dễ nhìn thấy và cảm nhận được rõ rệt. Tuy nhiên, đóng góp của nó vào sự phát triển cơ bắp không phải là yếu tố duy nhất.

Pha co cơ lệch tâm (Eccentric): Đây là giai đoạn cơ bắp kéo dài ra khi chịu lực. Trong bài squat, đây là giai đoạn bạn từ từ hạ thấp người xuống. Nhiều nghiên cứu đã chỉ ra rằng pha lệch tâm tạo ra nhiều tổn thương cơ hơn so với pha đồng tâm. Sự tổn thương cơ này, tuy nghe có vẻ tiêu cực, lại là tín hiệu kích thích tăng trưởng cơ bắp. Cơ thể sẽ sửa chữa và tái tạo các mô cơ bị tổn thương, dẫn đến sự phát triển về kích thước và sức mạnh.

Vậy, phương pháp nào tốt hơn?

Câu trả lời không đơn giản là “đồng tâm” hay “lệch tâm”. Cả hai pha đều đóng vai trò quan trọng trong sự phát triển cơ bắp. Tuy nhiên, nhiều bằng chứng cho thấy pha lệch tâm đóng góp nhiều hơn vào sự tăng trưởng cơ bắp. Điều này không có nghĩa là bạn nên bỏ qua pha đồng tâm. Pha đồng tâm vẫn cần thiết để hoàn thành chu kỳ chuyển động và kích hoạt sự tăng trưởng cơ bắp.

Một phương pháp hiệu quả là tập trung vào việc kiểm soát pha lệch tâm. Hạ tạ xuống chậm hơn, có kiểm soát sẽ tạo ra nhiều tổn thương cơ hơn, thúc đẩy sự phát triển cơ bắp mạnh mẽ hơn. Bạn có thể sử dụng trọng lượng nặng hơn trong pha lệch tâm so với pha đồng tâm. Ví dụ, bạn có thể sử dụng hỗ trợ để nâng tạ lên (pha đồng tâm) nhưng tự mình hạ tạ xuống một cách chậm rãi và có kiểm soát (pha lệch tâm).

Kết luận:

Sự phát triển cơ bắp hiệu quả phụ thuộc vào việc cân bằng cả hai pha đồng tâm và lệch tâm. Tuy nhiên, việc tập trung vào việc kiểm soát và tăng cường pha lệch tâm có thể mang lại kết quả đáng kể hơn. Hãy nhớ rằng, việc lắng nghe cơ thể, điều chỉnh trọng lượng và kỹ thuật phù hợp là điều cần thiết để tránh chấn thương và đạt được mục tiêu tập luyện của bạn.

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Have you thought about the different phases of exercises you do in the gym? Take the humble squat, for example. You lower into the squat, pause at the bottom, then drive upward to stand; these three phases are called eccentric, isometric and concentric muscle contraction, and if your goal is to build muscle or strength in the gym, you need to know more about them.

Most of the time, our focus as gym-goers is on shifting weight at the most resistance — lifting a weight up, standing from a squat, or pulling ourselves over the bar during a pull-up — but it turns out that each movement phase can benefit you, your strength gains and muscle hypertrophy (that’s muscle growth).

Black Swan Training. “Athletes often hold positions where muscle fibers are activated, but the joint angle and muscle length remain static.

“Think of a gymnast holding a planche or an iron cross on the rings. In these movements, muscles like the shoulders, core, and biceps work hard to maintain stability without shortening or lengthening.”

Marchant explains isometric exercises can also strengthen intra and intermuscular coordination — how well muscles within a muscle group (intra) or between muscle groups (inter) work together, as they require “high levels of muscle recruitment to maintain tension and stability.”

Over time, this can improve strength, endurance and neural activation — vital for holding static positions under stress.

Concentric vs eccentric vs isometric training: Benefits

Focusing on all three phases of movement can help you build strength, muscle, power and control during exercise. But like anything in life, different goals require different training stimuli, so you might focus on adapting your training programs accordingly.

“The benefits of eccentric contractions include muscle growth or hypertrophy…because they cause more microscopic muscle fiber damage than concentric contractions,” says Clift. “This damage is key for muscle growth, as the body repairs and strengthens muscles during recovery.

“Another benefit is enhanced strength…allowing you to handle heavier loads. It can also improve flexibility, helping stretch muscles under tension, which can enhance muscle flexibility over time.”

Eccentric training even improves muscle control and coordination as your body learns to resist gravity or external force during the movement.

“The benefits of concentric movements include enhanced muscle strength and power,” adds Clift. “Concentric contractions are responsible for the active movement in most exercises, helping develop explosive strength…they can also improve muscle endurance over time and aid functional movement.”

Think about any dynamic actions you do during the day, like lifting, climbing, pushing, or even sprinting and weightlifting in a sports setting — all require concentric contractions. “They are also beneficial for burning calories, requiring more energy than eccentric movements, making them effective for fat loss and metabolic conditioning,” he says.

You’ll find eccentric and concentric phases everywhere: running and quickly slowing to a stop, controlling the descent of a hill and climbing that same hill, or even changing directions while you walk. Stopping and starting — your body should be able to perform all these movements efficiently.

Isometric contractions can improve endurance and stability for your core and postural muscles, too. “They also offer benefits for joint stability, strengthening muscles without moving the joints,” adds Clift.

“This is especially useful for rehabilitation or injury prevention. Isometric training helps strengthen muscles at specific joint angles. This is particularly useful for athletes or individuals who need to develop strength at points in their range of motion.”

By including more controlled eccentric movements and isometric exercises in your routine, you could strengthen connective tissues like tendons and ligaments, ultimately improving stability, balance and control.

Over time, that translates to making your concentric lifts stronger, which makes sense, right? If you can control the lowering phase of a squat better, you can be more powerful as you push to stand.

Concentric vs eccentric vs isometric training: How to train for each phase

“Each type of contraction offers distinct advantages, but incorporating all three into a training regimen provides a comprehensive workout that enhances strength, endurance, stability and injury prevention,” Clift says.

He recommends a typical strength training program that includes a concentric phase for muscle strength and functional power, an eccentric phase for muscle growth, flexibility, and tendon strengthening and isometric holds for stability, endurance and joint support.

For eccentric training, focus on slowing down the lowering phase of an exercise, like lowering a barbell during a bench press for three to five seconds, and use heavier weights for eccentric-only training. “I’d recommend this type of training once or twice a week as it causes more muscle damage, and as such, recovery time is longer,” he says.

Marchant agrees, adding, “Tempo training is an excellent method…this extended time under tension increases control and strength while minimizing injury risk. Eccentric work can also be incorporated into exercises like squats, where the focus is on a slow descent, building resilience in the muscles.”

If you choose a heavier weight for eccentric loading (most people can handle more weight here), you may need a spotter to help you lift it during a concentric phase.

For concentric training, Clift says to focus on the lifting phase. “In strength training, this is typically the portion where you’re moving the weight against gravity. Since concentric contractions are part of most dynamic exercises, they can be trained in every strength session, especially when focusing on lifting heavy or working on explosive movements.”

“Dynamic work, such as lifting lighter weights with fast, explosive movements, emphasizes the concentric phase,” adds Marchant. “Doing medicine ball throws or barbell jumps with light loads can improve power and speed…particularly useful for athletes who need quick bursts of force, as it trains the muscles to contract rapidly and powerfully.”

Equally, you can go heavy on the concentric phase and focus on maximizing force exertion during the lift to build power.

Standalone isometric exercises during warm-ups or cool-downs are great or incorporate holds in tandem with dynamic exercises, like pausing at the bottom of a bench press or squat. Several times a week is enough (anything from once to three times) to notice improvements.

“Gymnastic movements like holds (planks, L-sits, or wall sits) can be introduced to strengthen tendons and ligaments,” Marchant recommends. “These exercises can be held for longer durations (30 seconds to a minute or more) to build muscular endurance and connective tissue strength. Isometrics can also be integrated into strength programs, where you hold a squat or push-up position for a few seconds to increase tension and stability in the joints.”

Concentric vs eccentric vs isometric training: Which is better for hypertrophy?

“For muscle growth, eccentric movements are generally considered more effective than concentric or isometric contractions,” Clift reveals. “However, all three types of contractions can contribute to hypertrophy and the best approach often involves a combination of them.”

Eccentric training typically causes greater muscle damage, signaling the body to repair and grow muscles stronger and larger. “Eccentric movements also increase time under tension…the longer muscles are under tension, the more they are stimulated to grow.”

As you can typically handle more weight during the eccentric phase, you can apply greater loads to the muscle. “Some studies suggest that eccentric-only training with heavy weight is very effective for muscle growth,” Clift says.

Marchant agrees, adding, “Concentric movements, while they cause more immediate fatigue, are crucial for the overall strength gains needed to support hypertrophy.”

Bottom line

“Ultimately, a well-rounded training program that incorporates all three types of contractions — eccentric for control and muscle damage, concentric for power and strength, and isometric for stability and tendon health — will be the most effective for hypertrophy, injury prevention and long-term strength gains,” Marchant says.

Isometric exercises won’t build maximal strength and muscle mass, but they can help bridge the gap by strengthening tendons and ligaments as muscles grow, improving how the body handles load.

If you’re working toward a one-rep max or enjoy powerlifting, concentric training might be more the focus, recruiting your fast-twitch muscle fibers, responsible for exerting power and force.

Those new to weight training may add eccentric-focused sessions to help build great technique and foundational growth and improve the mind-muscle connection. However, it can take longer to recover from eccentric sessions, increasing the likelihood of DOMS (delayed-onset muscle soreness).

While building a training program, schedule rest and recovery to avoid overtraining and focus on progressive overload principles to ensure you build gradually and safely. I always recommend working with a coach to optimize your schedule and plan training sessions, incorporating the methods above into your routine accordingly.

Periodization is the best way to do this, splitting a training plan into blocks — usually four weeks per block with a different focus throughout. It’s the best way to track, measure and build progress and adds a system you can easily follow.

Depending on your goals and ability, most of your time might be spent optimizing all movement at regular tempos, while you may add specific training (concentric-only, eccentric-only, or tempo training, for example) into certain weeks. Just remember, the more effectively you can handle all three phases, the better you’ll perform an exercise.

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