Here’s What You Need To Know…
1. Not all muscle contractions are alike. Each type of contraction offers unique advantages and disadvantages with respect to hypertrophy, strength, and power specific adaptations, as well as tissue repair and recovery.
2. Appreciating the differences between eccentric, concentric and isometric contractions will expedite your strength and hypertrophy goals while making you a student of the iron game, not just another meathead.
3. All athletes and lifters will benefit from at least some exposure to each of these different contractions at some point or another. The periodized ratios of each type of contraction are prescribed based off the athletes’ mode-specific goals.
So You Think You Know Your Contractions?
Eccentric, concentric, isometric, isokinetic, isotonic, plus all the butchered pronunciations you hear around the gym. The first three especially, are thrown around by the vast majority of trainers and trainees alike these days with little discretion.
Who cares what they mean, as long as they just make you sound like you know what you’re talking about, right? Wrong. I’m definitely a fan of people getting their science on, but I think we might all benefit from a refresher in the three most common types of skeletal muscle contractions, and more specifically, how to effectively implement them into a program to elicit optimal physiological adaptations.
So here’s the game plan, I will break down each of the “Big Three” contractions, and no I’m not talking about the bench, dead and squat. We will look at each type starting at the cellular level and end each section with suggested program implementation protocol to make each contraction instantly actionable for your training.
Eccentric Muscle Contractions
Yes I’m going to talk about eccentric contractions first. Yes I have a reason for that madness. The eccentric contraction is the Cinderella of the contraction family; constantly in the shadows of it’s much less worthy siblings (concentrics and isometrics). Since our ancestors first began lifting things millions of years ago, there has never been anything sexy about lowering a heavy load under control! That makes me sad, because focusing on eccentric specific resistance work will absolutely blow the top off of anyone’s progress. We’re talking about eccentric contractions first because they should be prioritized in EVERY program for EVERY trainee.
So what is it? An eccentric contraction is one in which your muscle fibers are producing force while actively lengthening (think biceps while lowering a dumbbell during a curl). At the cellular level, the myosin heads of your sarcomeres are rapidly detaching and reattaching to actin filaments to prevent whatever load or mechanical stress your body has been exposed to from causing acute trauma to your joints and tissues.
Your Strongest Contraction
What’s so special about an eccentric contraction? The eccentric contraction is the strongest type of contraction your body is capable of producing while actively moving. Studies indicate that as much as 20% more force can be generated during an eccentric contraction when compared to a concentric contraction. Eccentric work strengthens your muscle fibers over their entire ROM, which is meaningful for EVERYONE.
The physiology of an eccentric contraction explains this, and also explains why you will feel like you got hit by a freight train after an intense eccentric based training session. When you use a near or supra-maximal load, and implement slow-timed eccentrics, some of your myosin heads are literally ripped to shreds as your muscles struggle to control the load. Ouch! But, with adequate nutrition and rest, you can use this the extra mechanical damage to your advantage by amplifying your hormonal response to training.
As we all know, mechanical damage is one of the two most critical stimuli for hypertrophy and strength adaptations. It’s simple: if you cause more micro-damage and drive more metabolites into your muscle cells, then you’ll release more Growth Hormone and experience greater rates of protein synthesis, as long as your nutrition/sleep cycles are on point. Take this fact to gym next time you train and you will see why eccentric work is my go-to for strength and hypertrophy. If you can handle the DOMS, YOU WILL GROW!
How To Incorporate Eccentric Work Into Training Program Design
For beginners, eccentric work performed at 65-75% of their 1RM is an ideal method for jumpstarting motor control adaptations and an awesome teaching tool for ingraining movement patterns. Work a 3-second eccentric into major lifts like the squat variations, RDLs, and Push/Pull work. Additionally, many novice trainees are unable to perform the most effective compound lifts such as pull ups and push ups. We can help them along the way by assisting with the concentric portion of the movement (bands, jump, manual assist, etc.) and have them work the eccentric movement on their own since they are strongest there. No more playing around on the lat pull-down machine or doing pushups from your knees!
For hypertrophy oriented clients, eccentrics reign supreme. For anyone looking to build muscle, the eccentric portion of a movement should almost always be longer than the concentric. Tempo work is a great option in these athletes. Two to five seconds of eccentric work periodized into their program based on their goals and applied to all force production components (core work, and typical lifts) will accelerate their progress and help you optimize their training program.
For the most advanced trainees, supra-maximal loads in the range of 10-15% more than 1RM performed for 3-4 sets of 4-5 reps with an 8-second eccentric, will land you in the sweet spot for time under tension (40-70 sec per set), while causing more micro-damage than a sub-1RM set performed with identical tempo.
Make sure you have a spotter or two handy on supra-max eccentric days as things can get hairy moving that much weight for that amount of time. Spotters are also required to assist in the concentric movement as you are working North of your 1RM. Start by picking one compound movement for each body part and use these slow negatives once every two weeks, keeping the rest of your program static.
If you are adequately recovered by the time your next eccentric session rolls around, consider increasing the frequency of eccentric work. If the DOMS or CNS fatigue is negatively affecting your other sessions, cut back on frequency. This is an intensifier and should be used to stimulate new growth, not obliterate your body.
For strength and power athletes, eccentric work offers the most bang for your buck in terms of strength gains. Strength athletes will benefit from the same methods implemented in advanced hypertrophy trainees, with 2-5 second eccentric work a mainstay, and supramax work added in as desired. As a coach/trainer be sure to track their numbers if you are implementing a lot of eccentric work. It is your job to make sure your athlete is peaking at the right time, so find a happy medium between stimulation and recovery. Since most athletes in this category compete in an activity requiring strength/power to perform well, it is crucial to take into account both the pros and cons of eccentric training.
Due to its ability to improve strength quickly, eccentric training should absolutely have a place in any strength/power athletes training arsenal. Due to the increased recovery time and demand on the CNS, eccentric work should be tapered or completely dropped from a program nearing competition in order to keep the athlete fresh, both mentally and physically. There is nothing worse than trying to PR in the deadlift 3 days after performing supra-maximal RDLs. So focus on eccentric work early in the training cycle, build a base, and then cut back from there.
Concentric Muscle Contractions
This is the poster boy muscle contraction. Ask someone to flex and they are going to perform a concentric contraction. Take a walk through your local gym and you will see all kinds of emphasis being placed on concentric work (form…not so much). Concentric work is popular because it’s visible. We can see it happen. A muscle balls up, becomes larger and more pronounced, and looks, well, just flat out cool. Concentric contractions are ultra important for athletes because they are required for maximum force production during every single open chain movement (throwing, kicking, etc.)
So what is it? A concentric contraction occurs when your muscle produces force while actively shortening (think biceps while curling a dumbbell up). The myosin heads climb their way up actin filaments, shortening each sarcomere along the way. The maximum amount of overlap between actin and myosin occurs somewhere in the middle of the muscle’s ROM (which we will talk about shortly in the isometric section), and tapers off at the extremes of the ROM. Less overlap equals less force production. Got it? Good.
The Role of the Concentric Contraction
So if eccentric work is so great, then what do I use concentric work for? Similar to eccentric contractions, concentric work strengthens a muscle over it’s entire active ROM. That means that the entire strength curve of a muscle will improve. For athletes, moving fast is crucial. If we wish to intelligently design any athlete’s program, then concentric work will play an integral role in replicating mode specific movements (jumping, sprinting, hitting, throwing, kicking, etc.) Think of it as using eccentric work to build a foundation of strength and hypertrophy, and concentric work to develop speed and power.
This next characteristic can be both an advantage or disadvantage depending on how you look at it. Concentric contractions require less neural drive and cause less mechanical damage to your muscle cells. Remember our strength and power athletes’ needs from the section above? This makes concentric work a good thing, as less DOMS and CNS fatigue will be incurred with training, allowing for more training volume near competition phases without running our athlete into the ground. Worried about maximizing the amount of muscle you can pack onto your frame? Then you probably don’t want to give too much thought to concentric specific work, unless you are nursing an injury or becoming stale due to too much eccentric work.
How To Effectively Implement Concentric Work
Foundational Strength Emphasis
For beginners, concentric work is crucial because it teaches them what it feels like to contract a muscle. We want them to develop the neural pathways and motor control required to progress their training programs, and hard, peak contractions play an important role in terms of teaching them what a movement consists of (a good stretch and a hard squeeze). Concentric contractions are awesome with tempo, especially since very few people incorporate them in their programming. If your client struggles with coordination, work on tempo concentric work with dumbbells and watch those neural pathways grow!
For all hypertrophy oriented athletes, the concentric contraction should definitely not be ignored. We will talk in the next section about combining concentric and isometric work for these athletes; but needless to say, a HARD concentric contraction performed deliberately, offers many of the same benefits in our beginners, specifically, connecting our athlete’s mind and body. Perhaps my favorite application of concentric work in this population in in their metabolic conditioning work. Let’s say we had a client train legs today, and they are scheduled to train back and chest tomorrow. That limits us in terms of movements we can thoughtfully prescribe as we try to avoid pre-fatiguing those muscles.
We also know that very few approaches to ramping up the metabolism are as effective as explosive interval work. So what do we do? Yup, concentric only explosive movements. We could stack concentric only hybrid sled pull/rows, with a med ball or keg toss and not have to worry about any of the additional DOMS in our client’s chest and back. This is a great practice, especially for high level athletes who need to remain lean but also train with a bodypart split. And it’s flexible, so we can use all kinds of movements based on upcoming training sessions.
Power and strength athletes compete and perform by showcasing their muscles’ ability to contract concentrically (think Bench, Squat, Deadlift, and the Olympic Lifts). They should be trained accordingly. Remember, it is helpful for you as a coach/trainer to think of eccentric work as a tool to build their strength and hypertrophy foundation, and then transfer that into power and speed with concentric work. Concentric work will sharpen the sport specific skills (more similar to performance goals) more so than eccentric work, so periodize accordingly.
Isometric Muscle Contractions
Isometric contractions probably get even less love than eccentric contractions, but we are about to change that! Back in the day, isometric training was king. Ancient forms of Yoga implemented isometrics in their many forms of static holds thousands of years ago. Before lifting weights was mainstream, static holds were the primary mode of resistance training!
So what is it? An isometric contraction occurs when a muscle is generating a force without any change in its overall length. Myosin heads attach, and are replaced by higher threshold motor units when they fatigue. Although myosin attaches, there is no translational movement occurring on the cellular level, thus, our muscles do not change length.
So if eccentric contractions build a base and concentric contractions build mode specific skills, why do I need to worry about another contraction? Isometrics are the icing on the cake, and they will help you bust through plateaus to hit those much-desired PRs. They can be used to cause eye-crossing pumps and improve motor control and proprioception. You can definitely build muscle and strength with this type of contraction. However, there are some limitations. Mainly, that a muscle is only strengthened in the position it is called upon to produce force. Like I said, I like to think of isometrics as the finishing touch to a program, and use them to a) drive as much blood flow and the accompanying metabolites into a muscle following a normal set/rep scheme b) target any sticking points in lifts like the bench, squat, and deadlift and c) strengthening a muscle at the extremes of its ROM.
How To Harness The Power of Isometric Work
Foundational Strength Emphasis
In beginners, incorporating a 1-3 second isometric hold at peak contraction is another effective method for teaching sound activation techniques and developing their mind-muscle connection. I especially like isometric core work. No I’m not talking about planks, we are talking RKC plank and its variations. Teaching beginners effective bracing techniques will save you countless headaches as it aids in injury prevention. No one performing an RKC plank correctly should be able to hold for more than 20 seconds. Don’t believe me? Try it!
For hypertrophy oriented clients, we have already learned that eccentric work can help incur maximal mechanical damage, one of the two stimuli for protein synthesis and muscle hypertrophy. Isometric work can be used to target the other stimuli, cell swelling. After performing a set, flex the target muscle as hard as you possibly can in the fully contracted position for 10-15 seconds. I love showing this one in person because you can literally watch the muscle tissue fill up with blood (and the growth inducing metabolites it carries) and see the veins start popping. Incorporating isometric contractions in this manner amplifies the metabolic stress placed on your muscle cells. More stress equals more stimulus to adapt. Booyah.
Power and strength athletes can benefit tremendously from isometric work, especially with a smart trainer prescribing when and where to use it. For you powerlifters and Olympic lifters, how frustrating is it to hit a sticking point? Sometimes, the only thing between you and a new PR is a 3-inch portion of a movement. Wouldn’t it be great to be able to get stronger in just that section of your ROM? You can! Let’s say you hit a sticking point halfway between parallel and upright in your squat. You have no problem getting out of the hole, and with a little spot you bounce right up from your sticking point. What do you do? Try this one: set the bar at the exact height you hit your sticking point and load it up with enough weight so that you won’t be able to move it. Get under the bar just like you were going to squat and drive HARD for 5-6 seconds. You won’t be able to move the bar, but you will learn to produce more than enough force than what is required to get you past your sticking point. This form of isometric work can be applied in the bench, the dead, any of the clean progressions, and more if you get creative! REMEMBER to breathe when performing isometrics. We don’t need anyone becoming a case study for occlusion training for the brain. Use this method on the last few sets after your other reps are completed for a 2 weeks, and then go get that PR!
Putting It All Together
Each of the three muscle contractions offers distinct advantages and disadvantages depending on your goals. A well designed program combines all three, with the periodized ratios dependent on the mode-specific performance outcome you are seeking.
It’s helpful to think of eccentric work as the foundation for strength and hypertrophy, concentric work for translating strength into power and speed, and isometrics as a tool to customize any program based on your fitness/performance goals. Now go out and get after it already!
About The Author
Ian Padron is a graduate of the University of Wisconsin’s Exercise Science Program and an ACSM Certified Personal Trainer, currently residing in Seattle, WA. Ian’s mission is to revolutionize the health and fitness industry by combining science and education to evoke sustainable change in his clients and readers. He preaches the importance of a holistic approach to training, taking into account the mind AND the body. Ian also walks the walk as a natural competitive bodybuilder.
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*All Images Are Copyright of Dr. John Rusin and John Rusin Fitness Systems, LLC