October 25, 2022 10 min read
When you're moving through a strength workout, how much thought do you give to the different muscles you target, and how you target them? It can be easy to zone out while going through rep after rep, same-old, same-old.
As it turns out—there’s a whole lot more to the down and up motions of squats, or the lift and lower of biceps curls—each part or phase of every exercise plays a distinct role.
If you have any goals to which you’re working, understanding the different phases of your exercises can not only make it more interesting, but it can also make a significant difference in your progress.
Each exercise consists of different movements — pulling, pushing, lowering, and lifting. Squats are not just squats, and breaking them down could benefit your workouts. In every strength training exercise, there are three parts: concentric, eccentric, and isometric exercises. Each phase has its own benefits and challenges.
An isometric phase of an exercise is when a muscle is under tension but static. An example is performing a static bicep hold by holding out two dumbbells with both arms at a 90-degree angle. Getting the dumbbells up, and placing them on the floor afterward are concentric and eccentric movements, but the period of non-movement when the dumbbells are held up is the isometric contraction.
Another example is doing static stretches to cool down after working out.
That phase when you hold a stretch for 30 to 45 seconds is the isometric phase.
In this article, we will focus on the movement phases— concentric and eccentric types of contractions— of exercises.
Here’s why it is important:
During resistance training for muscle building, both eccentric and concentric movements have been shown to be equally important. Using both concentric and eccentric contractions in your strength training program can lead to substantial increases in strength over the long term.
Concentric movements occur when your muscle fibers shorten or contract. The concentric portion of a movement works against the force of gravity and is known as a “positive” movement. Think of raising your arm away from the ground in a bicep curl, and how you can feel your biceps working.
Imagine doing a bodyweight squat. As you go from the lowest point right up to the standing point, you're lifting your body weight load against gravity—that's the concentric phase of the squat.
Now what's happening here is that as the major joint actions occur, you've got your main muscles or prime movers, and your synergist muscles all contracting and shortening to allow that load to resist gravity on the way up. This is why you can feel it in those muscles, especially when you start adding a load.
Most of the typical bodybuilding style movements have a concentric muscle contraction portion.
Bench press: Pushing up in bench presses contracts your chest muscles and your triceps.
Barbell or dumbbell curl: The lifting upwards portion of the curl
Squat: The standing-up movement of a squat
Push-up: Pushing up from a lowered push-up
Sit-ups: The sitting-up movement of a sit-up
Deadlift: Lifting a barbell off the ground at the beginning of a deadlift
Bent over row: The lifting portion towards your abdominal region
Pull-ups: Pulling yourself up to the bar in a pull-up
Typically, the more difficult portion of an exercise uses a form of concentric contraction. When people are focused on increasing weight moved, the concentric portion is what they are referring to.
Concentric contraction exercises are the most relied-upon exercises in many people’s strength training toolboxes. However, it’s very difficult to isolate concentric training — primarily because you're working against the force of gravity.
For example, isolating the standing-up phase of a squat, which is the concentric movement, will require the eccentric movement to squat down first. In almost all exercises you need the eccentric movement first (lowering down to parallel).
There are a few exceptions. For example, isolation of the concentric phase of a push-up is possible if you lay face-down on the floor before pushing yourself up. Or, when performing a deadlift, simply drop the barbell when you reach the top of the movement.
Muscle Development: Adding more weight and repetitions is a method called progressive overload. Tracking progress is easier through concentric contractions, and over time, progressive overload helps increase muscle mass.
Decreased muscle soreness: You will experience less muscle soreness by isolating concentric movements since eccentric training causes more muscle damage.
Perfecting your form: If you have a problem with your form, concentric training can help. Issues like legs caving in when you stand up from a squat is an example of the sloppy form that typically occurs in the concentric phase of an exercise. By isolating this part of the movement, you're able to target the problem areas.
Function Benefits: Many exercises such as deadlifts and squats focus on primal movements. Increasing the loads you can handle on the concentric phase of the exercises will also benefit your everyday activities. Being able to lift heavy weights overhead or pick up objects off the ground is a great help in life outside the gym.
Increasing fast-twitch muscles: If you’re working on increasing your power or sprint speed for performing exercises like a power clean, isolating concentric movements executed with speed is a valuable process, but good form is essential.
Strength Enhancement: If you want to track strengthincreases over time, concentric movements are the best way to get it done. When you increase the amount of weight you can deadlift, squat, or bench, you are increasing the amount of weight you can lift in a concentric motion.
Typically, the more difficult portions of exercises use a form of concentric contraction. When people say they are focused on increasing weight moved, they are referring to the concentric phases of their workouts.
Unlike muscle contractions, eccentric exercises involve increased muscle length. During the eccentric phase of an exercise, you work with instead of against the force of gravity, such as lowering your arms back toward your sides in a bicep curl. These are often referred to as “negative movements,” and have been shown to help increase strength and build muscle mass.
Let’s get back to the squat example where we used a concentric phase of the movement to stand up straight. All those contracted muscles like the quadriceps must now be stretched out to prepare for the next contraction to lift your body weight against gravity.
So, you use the eccentric phase to lower your body weight down into the squat. This movement elongates the tight glutes and quads, along with the joint actions of your knee flexor and hip flexor. You are now ready for the concentric phase of your squat.
Muscle growth happens when muscle damage occurs, which is a good thing, even if it sounds bad. Most muscle damage occurs during the eccentric training phase. That makes the growth of skeletal muscle cells, or muscle hypertrophy, one of the primary benefits of eccentric exercises. Unfortunately, this comes with increased delayed onset muscle soreness (DOMS) when compared to concentric movements.
Examples of eccentric exercises include:
Bench Press: Lowering the barbell toward your chest in a bench press
Squats: Lowering into a parallel squat position in a squat
Push-ups: Lowering into the bottom of a push-up
Crunches: The laying back movement in a crunch
Deadlift: Bringing a barbell back to the ground at the end of a deadlift
Sit-ups: Lowering your torso back to the ground in a sit-up
Pull-ups: Slowly lowering down from the top of a pull-up
Shoulder presses: Slowly lowering the weight from the top of a slow shoulder press
With the right movements and a few adaptations, most exercises can be turned into eccentric strengthening exercises. This involves focusing on the downward portion of the exercises. There may be times when you want to strictly focus on eccentric vs. concentric training.
Eccentric activation exercises — called negative training — can help with building muscle strength. Negative movement performance boosts progression toward advanced movements like pull-ups or push-ups. In comparison, focusing on concentric training is significantly rarer, but can help build speed and power.
Negative training involves the performance of particularly slow eccentric muscle contractions, aiming for gradual strength building.
Eccentric push-up: Are you a beginner struggling to master push-ups? Start at the top of the plank—no knees, toes only— then slowly lower yourself to the ground. Once you reach the floor, use your hands and knees to return to a plank position, and repeat the slow eccentric contraction.
Eccentric pull-up: Without momentum, a full pull-up is one of the hardest bodyweight exercises. Start by using a resistance band or a step stool to get yourself above the pull-up bar. From there, gradually lower yourself to a fully extended form, then let go. Climb up the steps again and repeat the slow movement.
Eccentric boat pose: If you aim to target your core, start in the top of a boat pose, a hollow body hold, then slowly lower yourself until you're fully extended. Try to take as long as you can.
Handle more weight: Your body can handle significantly heavier loads in the eccentric phase of an exercise. If you are bench pressing a spotter or your personal trainer could help lift the weight upwards for you to lower the weight in a controlled movement in the eccentric contraction portion of the exercise. Over time, this negative training move may significantly increase your muscle growth.
More muscle damage: Have you ever noticed highly advanced bodybuilders use relatively light weights with maximum control? Follow their workout routines, and you will learn they’re working on increasing muscle damage. Something about that sounds wrong, right? No, it’s a good way to get their systems to repair and rebuild stronger muscles, maximizing strength gains.
Reduce the risk of injury: Negative training strengthens tendons and ligaments that are damaged from the long-term performance of concentric exercises in workout routines. By focusing on lighter weights with eccentric movements, you can help limit potential injuries.
Improved flexibility: Performing heavy negatives over time can help improve flexibility. Heavier gym goers and bodybuilders tend to have loads of strength but many of them lack flexibility. Negative training focused on eccentric movements can help improve such deficiencies.
It can get a little bit confusing when you start looking at different types of exercises, but you want to remember that it's the load that is going against gravity, and not necessarily your arm, torso, legs, or other body parts that make a contraction concentric or eccentric.
Understanding that part is crucial when you use resistance equipment at the gym for your strength-building workouts. In some machine workouts, the up movement is not necessarily concentric.
A good example of this is the lat pull-down machine. Imagine for a moment that you're on a lat pull-down machine and at the starting point. You’ve stacked the weights, and the handle of the pulley is up high.
So, all you do is grab the handle and pull down on it, and as you pull down on that bar the load goes up against gravity, working the targeted muscles.
Therefore, that's your concentric phase, and not eccentric as we explained for lowering your arms. In this case, lowering your arms causes your muscles to tighten against the resistance of the load going up. Then as you release the bar back up, you're on the eccentric phase where your muscles are stretched to ready them for the next pull down.
However, this does not apply to all machine exercises.
Take the leg roll exercise you do on a machine to work your hamstrings. The load lifted against gravity is done by your legs lifting the weight, causing concentric contraction, and the eccentric phase occurs when you lower your legs.
Another consideration when breaking up an exercise in contraction phases with and against gravity to keep in mind is that one movement can be a concentric contraction and change into an eccentric contraction at a stage in the range of motion. Imagine yourself doing dumbbell pullovers. As you lay on the bench or gym ball, you lift the dumbbells against gravity up to your head in the concentric phase of the exercise.
But then you don’t stop there. Your arms, loaded with the dumbbells continue past your head, and you lower them as far as you can toward the floor. So, from the moment your arms pass your head, they are no longer moving against gravity, changing the movement from concentric to eccentric.
Bringing them back to the starting position will start with a concentric contraction, and change into an eccentric movement once it goes past your head.
Understanding that the phase of the muscle movement is determined by where the load is, and in which direction it moves, in relation to gravity is vital.
You can then use that knowledge to break down your exercises into different phases when you work out on a chest press machine, a leg press machine, or any bodyweight exercises.
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The answer to the question about which is better in Concentric vs. Eccentric exercise depends on the gym goer’s goals. While every exercise comprises both contraction types, those who have reason to isolate one or the other will regard their choice of contraction better for meeting their goals.
Balanced training requires both muscle contraction types. A lack of any eccentric training or concentric training in your workout routines is like leaving half a juicy steak on your plate. You will be missing out on the benefits of half the exercise, jeopardizing your chances of building muscles that turn heads.