The overarching goal of any successful strength program is to, well… make you stronger. No groundbreaking news there. But as a coach, it’s incumbent on us to fluctuate, modify, and temper a host of training variables to effectively and appropriately apply the necessary stimuli for our athletes in order to achieve ‘progressive overload’, making them stronger and ultimately better athletes. This is something that is concentrated on ad nauseum in academic and credentialing realms. The primary variables emphasized for most include the basics- intensity, volume, rest time, exercise progression, etc. Within the last decade or so, it has become more widely practiced to include more nuanced variables such as analyzing bar speed (velocity-based training), adding accommodating resistance (bands or chains), or adding tempos to conventional movements.
Every muscular action is comprised of three distinct contraction types- eccentric, isometric and concentric muscle actions. Eccentric muscle action is the lowering phase of a movement whereby the muscle (and tendon) are stretched and/or lengthened. Conversely, concentric muscle action refers to the ascent portion of a movement, in which the muscle is contracting and/or shortening. Finally, isometric refers to the point between eccentric and concentric action, in which there is no movement or contraction actively occurring. Whether you are typing on your phone, performing a PR clean & jerk, or anything in between, movement cannot occur without all three of these actions taking place.
Applying specific tempos in strength training is far from some recently discovered revelation. In fact, we can probably date tempo training back to the early 1900’s, as with almost anything we see in strength and conditioning today. That said, there has been somewhat of a resurgence for tempo work over the last decade or so, in part (I believe at least) due to the open source sharing on social media, and I suppose it being more emphasized in academia/credentialing. For me personally, I was truly enlightened on the concept of tempo training and all of its wide-reaching ramifications by way of Triphasic Training (Author- Cal Dietz) which is unequivocally one of the best S&C books I’ve yet to read. In either case, tempo training has gained some steam and it absolutely should be, because this is something, personally, I feel is a non-negotiable component with training my athletes.
But why exactly do we use these tempo applications in training? And better yet, what exactly are the benefits of using tempos? In this article, we’re going to discuss just that- the how, why, and when of tempo training, by concentrating on the eccentric and isometric tempo applications. I’m going to hold off on discussing the reactive tempo for now, as I’m planning on covering reactive training in a standalone article to follow. Nevertheless, at the most basic level, eccentric emphasis training is performed by exaggerating the lowering phase of any given movement with a deliberately slow and controlled tempo. Isometric emphasis is an exaggerated pause between the descending (eccentric) and ascending (concentric) phases of movement. The videos below depict these in action:
Barbell back squat w/ eccentric emphasis:
Barbell back squat w/ isometric emphasis:
Quick Physiology 101 Interjection: Before I get into the specifics of eccentric and isometric training, I wanted to cover some quick noteworthy points on general neurophysiology to help clarify any potentially confusing points discussed. When you boil it all down, force production is the result of the stretch reflex-GTO reflex (GTO = golgi tendon organs) (1). The stretch reflex is one of the most powerful mechanisms of the human body and is the byproduct of the muscle spindle fiber stimulation minus the GTO inhibition; the sensitivity, or conditioning of each is extremely important for resultant force production. Your muscle spindle fibers are proprioceptive bodies found in the muscle that detect changes in muscle length and send signals to the brain to tell the muscle how hard it needs to contract (1). Conversely, GTO’s, which are proprioceptive bodies found in the musculotendon junction detect changes in force and send signals to the brain to instruct the muscle to relax (1). Think of GTO’s like having a brick under your gas pedal that’s strategically positioned to prevent you from going above 60 mph. GTO’s are the overbearing parent, who are well intended but intercede far more than they really need to. Both of these proprioceptive bodies are constantly at work and involved in any muscular action no matter the demand or complexity. What’s even more bizarre, is that every time the muscle spindle fibers or GTO’s transmit signals, the messages are sent to the brain and returned in under 0.01 seconds (2)! Takeaway point being, adding tempo work into your training will specifically target these proprioceptive bodies and retrain the central nervous system to stimulate and inhibit more adequately.
Eccentric emphasis: YOU CAN’T SPEED UP WHAT YOU CAN’T SLOW DOWN
As mentioned, eccentric training is performed by exaggerating the lowering phase of any given movement with a deliberately slow and controlled tempo. There is a myriad of ways to apply eccentric tempos, ranging from supramaximal eccentrics in which the external load is 105-125% of the athletes true 1-RM (or “negatives” as some of you old heads may know it as), overload-release techniques, or just standard eccentric training with an array of applied intensities. Irrespective of the specific eccentric application, it has been widely reported that eccentrics are a premiere way to increase muscular hypertrophy (the growth of muscle fibers). Eccentrics are also a mainstay in rehab training following injury, but we’ll circle back to that. For the sake of this article I’m just going to do a broad overlay of what and why, as well as how I personally use these techniques.
By biological default, we are generally stronger in eccentric muscle actions when compared to concentric, in part because we are working with, rather than opposing gravity. Another reason for this is that we are able to tolerate load more advantageously than we are able to produce force. The belief on this is that due to the increased tension under load that occurs, fast twitch muscle fibers (type II fibers) are recruited earlier to accommodate, representing a reversal in the size principle (3). The physiological mechanism occurring during eccentrics is an induced mechanical stressor on the contractile properties- myofilaments and sarcomere (5). In essence, the human body needs to be broken down and damaged before repairing and growth can occur, using eccentric tempos in training is a highly efficient way of amplifying this process and has been pretty much universally accepted as an effective training means in this regard. Additionally, eccentric muscle action actually expends a lower metabolic energy requirement, because some cross-bridges are forcefully detached due to the stretching of the muscle fiber, thus utilizing less ATP (3). Although eccentrics are notoriously known to induce greater residual soreness, the energy used during training is lower when compared to ISO’s or concentric muscle action. So the athlete can actually perform fairly more total work during eccentric-based training (even if it NEVER feels that way).
Isometric Emphasis: THE ATHLETE IS ONLY AS STRONG AS THEIR WEAKEST LINK
The purpose of isometric emphasis isn’t quite as cut and dry as eccentrics, and frankly there is still some debate as to precisely what mechanism is occurring during isometric tempo training. That said, my belief (also reasonably supported by research) is that isometric training is a highly effective way of increasing neuromuscular traits such as motor unit recruitment and rate coding (4). Motor unit recruitment refers to the precise number of muscle fibers that fire (or contribute) during muscular contraction (4). Rate coding refers to increasing the rate at which these fibers fire… I know, go figure. Increasing motor unit recruitment and rate coding are wildly important for athletic populations, and some would argue are the differentiating traits between ‘good’ and ‘great’ athletes. Simply stated an athlete with the ability to recruit and fire more muscle fibers is a stronger, more explosive athlete, and similarly, an athlete who can recruit these fibers faster is likely to improve their success in competition.
Joint angle specific training is another aspect of isometric training that has been subject of debate in recent years, creating quite a bit of fervor among strength coaches and sports scientists. You’ll see this most often with basketball players, as the majority of their sport is played at low angles of knee flexion. Not to mention, they are about as mechanically disadvantageous as could be for exercises like full-range back squats. This is another one of those ‘nuanced’ techniques that most sport scientists or researchers will tell you is pointless and “not statistically sound”, whereas some strength coaches will vehemently suggest otherwise. Personally, I think it makes a shit ton of sense and has prudence for athletic populations and those in rehab-based training. Just as it’s described, joint angle specific training includes isometric holds at specific joint angles that athletes are commonly subjected to in sport. An easy example of this, sticking with our basketball player theme, is to have the athlete perform basically a quarter or half squat and isometrically hold that angle. The thinking behind this is simple, if the athlete is fundamentally stronger at precise joint angles, that strength will better transfer to their sport. I tend to agree with this line of thinking. Joint angle specific training is also a highly beneficial strategy for injury rehab protocols, and for those who have accumulated injuries that have resulted in distorted movement patterns or ranges of motion as well.
Why tempo training matters: As I’ve emphasized over the last several months, my overarching philosophy on strength training is simple- if the athlete experiences it in sport, we train it in the gym. So, with this as our mental framework, consider the litany of tempos (or velocities) observed in any given sport. Consider acceleration, deceleration, top-end speed, angular speed, changing direction, body contortion and manipulation, absorbing, producing and delivering force, and so forth. Point is, in any sport, there is a spectrum of speeds at which movement takes place. For that reason and that reason alone, I find it critically important to integrate tempo training with my athletes. Moreover, I feel confidently that applying tempos to training does two things that are extremely difficult to replicate through other training means- (i) force the athlete to be conscious while performing the movement and (ii) develop bigger, faster, more responsive neural pathways. This is especially true in younger/novice athletes who have yet to develop proficient motor control, end-range stability, and general movement consciousness or kinesthetic awareness.
When we utilize tempos, either eccentric or isometric, we are manipulating the effects of these proprioceptive bodies, which again can be extremely important for performance. With eccentric training we are improving the neuromuscular synchronization of the neural pathways between muscle spindle, CNS and muscle, while also desensitizing the GTO (5). Recall the brick and the gas pedal analogy above… what we are effectively doing with eccentric tempo training (especially heavy eccentrics) is telling our brains “YES WE CAN!” when your GTO’s want to shout “NO THE FUCK WE CAN’T!!” (TECHINICAL TERMS). Or to build on the metaphor, adjusting the brick to halt us at 80 mph, instead of 60 mph.
As for isometrics, what we are predominantly getting out of isometrics is “teaching” the neuromuscular system to tolerate external forces, throughout a spectrum of angles/positions, by augmenting more efficient and responsive neuromuscular pathways (5). Again, if we can recruit more muscle fibers, AND recruit them faster, we are unequivocally building a more robust athlete. Personally, I feel like isometrics are quintessential for durability and possibly mitigating injury potential, as well.
How to implement:
I hate to sound like I’m holding out on you all, but again, there are a million different ways you can incorporate tempo work into your training. So this is just an overview of how I personally utilize tempos, we’ll start with eccentrics.
I. Implementing Eccentrics
-Eccentrics are best suited for hypertrophy training phases, which is usually my second mesocycle (2nd of 3-4 mesocycles). This will ultimately account for roughly 25-33% of the total macrocycle. The important takeaway from that is that I’m not hammering heavy eccentrics for months on end. Similar to most training variables, I phase them in, and phase them out.
-Eccentrics can be performed for literally any exercise. But some of my favorites are bench, squat, dead, RDL, lunges, OH press, and sit-ups/push-ups/pull-ups.
-I will typically use them in my second block of individual training days. So here’s what a sample day would look like:
1A.) Back Squat (x8) @80%
1B.) Hip mobilizer
2A.) Back Squat- 4 sec. Eccentric Emphasis (x4) @60%
2B.) Depth Jump (x4)
3A.) BB RDL- 4 sec. Eccentric Emphasis
3B.) DB Goblet Reverse Lunge- 4 sec. Eccentric Emphasis
3C.) Reverse Hypers
II. Implementing Isometrics
-I predominantly reserve my isometric work for strength training phases, which are typically my third mesocycle. Similarly, ISO’s will account for roughly 25-33% of the total mesocycle and are also phased in and phased out.
-ISO’s can also be performed for just about any lift, but what’s unique to ISO’s is that they can be performed at various positions throughout movements. For example, I can use ISO’s on a hex bar deadlift and have the athlete pause immediately after separating from the floor, below or above the knee, or combination holds which prompt the athlete to pause at multiple positions. See video below for an example.
-I will integrate ISO work into training the exact same way I displayed eccentrics outlined above.
A Few Final Notes:
Motor control is an absolutely imperative aspect to all things athletics and sport performance. Many of the world-leading researchers and coaches will often argue that conventional strength is a distant second to nervous system function when we’re discussing the traits of top-level athletes in the world. In essence, strength is great, but being able to control the strength you possess is really where it’s at. When we utilize tempo training with our athletes, it is the motor pathways that benefit the most. I alluded to it a few times throughout the article, but I feel this is most significant with young/novice athletes, as well as athletes who are coming off of injury. To close this out, I wanted to leave you with just a few bullet points on these two populations.
-We’ve all seen the kid that walks around like a newborn giraffe… yes, the awkwardness in his/her gait is in part due to rapidly growing limbs and lacking joint stability. However, the majority of this awkwardness is attributable to a nervous system that is still developing, which is the reason executing complex tasks look painfully awkward. For these young athletes, eccentric and isometric work can be beneficial in helping the athlete learn their body and help the nervous system develop a bit quicker.
-Tempos are also a great way to deter kids from wanting to do nothing other than “add more weight”. Eccentric and isometric work is remarkably humbling, and a good reminder that there are other ways to increase difficulty before simply adding more weight.
-For young athletes, there doesn’t need to be some clean, empirical progression plan with this. Hell, we can simply throw them in to their warm-ups, use them as intraset work, or even just apply tempos to auxiliary exercises ad lib style. For this crowd, I really like the following exercises for isometrics: birddogs, deadbugs, lateral lunges (or any lunge really), and push-ups. As for eccentrics, I really like these lunges, step-ups, pull-ups, hinges, and sit-ups.
-Almost every athlete I work with is either injured or coming off an injury. Make no mistake about it, I am far from an expert on rehab work, but I’ve done a decent job of learning on the fly. What I do with this population is very carefully analyze their natural movement patterns and whittle away to expose weak links in the chain. Once those weak links have been identified, I try to hammer them. A lot of the times these weaknesses are at peculiar or very particular points throughout range of motion, so this is where isometric work really comes in handy.
Example: Let’s say someone has a point in their squat pattern where they shift laterally during the ascent. What this tells me (**broadly) is that they have a leak in their movement. So, we will then go to a partial squat precisely where the weak point was identified and use an offset band attachment pulling them into the aberrant pattern. This will address the weak point and develop a broader motor pattern for their conventional squat. This technique is what is known as reactive neuromuscular training (RNT), or more simply, "pulling into the pattern." The theory behind this is that by actively pulling into the dysfunctional pattern, it will help the athlete to neurologically recognize the disconnect and be better capable to correct the movement.
-Athletes are exceptionally skilled with creating compensatory movement patterns. Quite frankly, it is their fundamental job to simply “find a solution” for every action they encounter in sport; and 99 times out of 100, that won’t be a “fundamentally sound” movement, it will be whatever the hell works. So in the training setting, they can often avoid injured sites, compensate for weak links, and bypass pain by creating their own solution. Tempos make this extremely difficult for the athlete. By controlling the speed of movement, we are effectively controlling one more variable that they now have to work through. Even athletes at the professional level are completely thrown off by simply forcing them to slow down or pause, and it will stress the hell out of them.
-Lastly, with all of my athletes, I always find myself circling back to one word- robustness. I want them to be strong, be strong in multiple positions, throughout a spectrum of angles, and at varying speeds. I strongly believe that by taking this approach, we are taking the blinders off (aka… overemphasizing “specificity”) and understanding that we really don’t know shit about the finite details of human movement. Especially in sport, and especially at the higher levels. We need to build strong and powerful athletes, no doubt, but I feel we need to consider durability and robustness on an even plane. And tempo training is another tool in the toolbox to achieve exactly this.
I covered quite a bit in this article, and per usual more than I originally planned. So as always, please feel free to reach out if clarity is needed.
References:
1.) Baechle, TR. Earle, RW., (2008). Essentials of Strength Training and Conditioning (4th ed.). Champaign, Il: Human Kinetics, 2008.
2.) Dietz C, Peterson, B., (2012). Triphasic Training. Hudson, WI: Bye Dietz Sport Enterprise.
3.) Mike, J. Kerksick, CM, Kravitz, L., (2015). Journal of Strength and Conditioning Research. How to incorporate eccentric training into a resistance training program. DOI: 10.1519/SSC.0000000000000114
4.) Schmarzo, Max., (2018). Isometric strength training. http://strongbyscience.net/2018/04/14/isometric-strength-training/?subscribe=success#blog_subscription-4
5.) Van Dyke, M., (2015). Advanced Triphasic Training Methods- CSCCa Presentation.