The lowering phase of an exercise is not just the part between repetitions. It is an active part of the movement that can help you develop strength, improve control and become more aware of your position under load.
This is known as the eccentric phase. It happens when a muscle produces force while lengthening, such as when you descend into a squat, lower a dumbbell during a curl or return from the top of a pull-up. Giving this phase more attention can improve the quality of your training, but current evidence does not support the idea that every repetition should be extremely slow.
What is eccentric training?
Most resistance exercises contain three types of muscle action. The concentric phase occurs when the working muscle shortens to move the load. The eccentric phase occurs when that muscle lengthens while controlling the load. An isometric action occurs when force is produced without visible movement.
Consider a squat. Your quadriceps and other working muscles lengthen under tension as you lower yourself. They then shorten as you stand back up. In a push-up, the descent is eccentric for the chest and triceps, while pushing away from the floor is concentric.
Eccentric training places deliberate attention on that lowering phase. This may be as simple as taking two or three controlled seconds to lower a weight. More advanced methods can use heavier eccentric loads, assistance during the lifting phase or exercises that place a strong demand on the lowering action, such as Nordic hamstring curls.
The important distinction is between controlling the eccentric phase and making it excessively slow. Control means maintaining tension, position and a consistent path. It does not require turning every repetition into a ten-second descent.
Why the lowering phase deserves attention
The eccentric phase can reveal weaknesses that momentum hides. A lifter may be able to drop quickly into a squat and rebound out of the bottom, but slowing the descent slightly can expose poor balance, a shifting foot position or a loss of trunk control.
Paying attention to the lowering phase can also make each repetition more consistent. Instead of allowing gravity to decide the speed and path of the weight, you remain responsible for the movement from beginning to end.
This has practical value across many exercises. A controlled dumbbell press can help you maintain shoulder position. A controlled Romanian deadlift can make it easier to keep the bar close and maintain the intended hip hinge. A controlled split squat can help you manage balance and depth without collapsing into the bottom position.
None of this means the lowering phase should become the only focus. Most people want to become stronger through the complete movement, so the lifting and lowering phases should work together.
Does eccentric training build more muscle?
Eccentric training is often promoted as a superior way to build muscle. The latest evidence suggests a more measured conclusion.
A 2025 systematic review and meta-analysis compared eccentric and concentric muscle actions across 26 controlled trials involving 682 participants. The researchers found no statistically significant overall difference in muscle growth between the two approaches. The certainty of the overall evidence was rated very low, and there was substantial variation between the included studies.[1]
Some subgroup analyses favoured eccentric training, including findings involving upper-body muscles, shorter interventions and certain measurement methods. These results are interesting, but subgroup findings should not be treated as proof that eccentric training is universally better. They may depend on the exercise, training method, study length and way muscle growth was measured.[1]
The most useful interpretation is that both eccentric and concentric actions can contribute to muscle growth. You do not need to choose one and exclude the other. A well-controlled full repetition already includes both.
For someone trying to build muscle, the bigger opportunity is often improving repetition quality and progressing the training over time. Adding a controlled eccentric phase may help achieve that, but it is not a shortcut that replaces suitable loading, enough challenging work and recovery.
Are slower repetitions better for strength?
A slow eccentric phase and eccentric training are related, but they are not exactly the same. Eccentric training describes the type of muscle action being emphasised. Eccentric duration describes how long the lowering phase takes.
A separate 2025 systematic review examined whether shorter or longer eccentric phases changed maximal strength, muscle growth and countermovement jump performance. It included nine studies and 166 participants. Around 46 per cent of participants were trained, and 77 per cent were male.[2]
The overall estimates for maximal strength and muscle growth were uncertain. Subgroup findings suggested that longer eccentric phases may produce similar or slightly greater strength gains in trained participants and when training volume was matched. Shorter eccentric phases were more favourable for countermovement jump performance.[2]
This matters because training tempo should match the goal. Someone learning to control a movement may benefit from a deliberate descent. An athlete trying to preserve speed and explosive performance may not want every repetition slowed down. A bodybuilder may use a controlled eccentric phase to maintain tension, but there is no clear reason to assume that making it longer will always create more growth.
The review also had important limitations. Nine studies is a relatively small evidence base, the participants were not evenly representative of the wider population, and the way shorter and longer durations were defined varied across research. The results provide useful direction, not one perfect tempo for everyone.
How long should the lowering phase take?
There is no single eccentric duration that is best for every exercise, goal or person. For general resistance training, a controlled lowering phase of roughly two to three seconds is a practical starting point. This is a coaching guideline, not a scientifically proven universal optimum.
The right speed should allow you to maintain your intended technique without turning the set into a different exercise. If the weight drops quickly, bounces at the bottom or pulls you out of position, the descent is probably too uncontrolled. If the repetition becomes so slow that you need to reduce the load dramatically or stop well before the target muscles are challenged, the tempo may be unnecessarily restrictive.
For strength and muscle development
Lower the weight under control, maintain the intended range of motion and lift with purposeful effort. The descent should be long enough to prevent dropping or bouncing, but it does not need to be exaggerated.
For technique practice
A slightly slower descent can give you more time to feel your balance, joint position and movement path. Once the pattern becomes more consistent, you can return to a more natural training speed.
For speed and power
Athletes should be cautious about making every eccentric phase slow. The review on eccentric duration found that shorter phases were more favourable for countermovement jump performance, which reinforces the need to match tempo to the quality being trained.[2]
How to add eccentric emphasis to your training
- Begin with familiar exercises. Apply a controlled descent to movements you already perform safely, such as squats, presses, rows, curls and split squats.
- Use a manageable load. Choose a weight that allows you to maintain the same position and tempo across the set.
- Control the descent and lift with intent. The aim is not to make both phases slow. Lower deliberately, then perform the lifting phase with appropriate effort.
- Change one variable at a time. If you extend the eccentric phase, avoid simultaneously adding more weight, sets and exercises.
- Start with one or two movements. There is rarely a need to apply a long eccentric phase to an entire session.
- Progress gradually. Add load, range, repetitions or eccentric duration only when you can maintain control.
More advanced methods, including supramaximal negatives or heavily loaded eccentric-only repetitions, require greater care. These methods can create substantial fatigue and should not be treated as a necessary part of everyday training.
Soreness, fatigue and when to be cautious
Unfamiliar eccentric work can create noticeable muscle soreness. This is particularly common when the exercise uses a long muscle length, a demanding range of motion or more eccentric volume than the person is used to.
Soreness is not proof that a session was more effective. It is feedback that the training demand was unfamiliar or difficult. Start with a modest amount, allow time to recover and avoid adding several intense eccentric methods at once.
Stop if you feel sharp pain, sudden weakness or a loss of control that feels different from normal muscular effort. If you are returning from an injury, managing a health condition or unsure whether a movement is appropriate, seek guidance from a qualified health or exercise professional.
The takeaway
The lowering phase matters, but it does not need to dominate every repetition. Eccentric training can support strength, control and muscle development when it is used as part of a balanced program.
Current evidence does not show a clear overall muscle-growth advantage for eccentric actions over concentric actions. It also does not support the idea that a longer lowering phase is always better. Different tempos may suit different goals, and the available research still has limitations.
For most people, the practical starting point is simple. Do not let the weight drop. Lower it with enough control to maintain tension and position, then lift with intent. You can find more practical, evidence-led guidance in the ProActive Health Group article hub.
Sources
- da Silva LSL, Gonçalves LS, Alves Campos PH, et al. “Comparison Between Eccentric vs. Concentric Muscle Actions On Hypertrophy: A Systematic Review and Meta-analysis.” Journal of Strength and Conditioning Research, 2025. View on PubMed.
- Amdi CH, King A. “The Effect of Eccentric Phase Duration on Maximal Strength, Muscle Hypertrophy and Countermovement Jump Height: A Systematic Review and Meta-analysis.” Journal of Sports Sciences, 2025. View on PubMed.
