By Carl Valle
Of all the classic periodization variables and principles of training, the density of training is the least clear in the scientific literature and the most abused in the coaching realm. Over the years, we have seen a rise in CrossFit-style workouts and a fall in understanding the way to connect terms like work capacity and energy systems into a program. At first glance, solving the training density conundrum is a lofty goal within just one article, but because the variable isn’t well-researched, not much but a few hypothetical conclusions are arguable. The promise of this article is that the average coach will be able to program density with a more sophisticated approach.
Defining Training Density
If you did a full meta-analysis of training density in sports performance, you would find very little information, save for a few theoretical summaries. While training theory is important for coaches to create a framework of planning, having no solid sport science makes the inclusion of any concept shaky. When more articles exist on the theory than actual investigations, we should step back and be very careful before rushing in. We already have a few explanations on training density with weight training and in conditioning fields, but not a general working definition.Training density is the sum of work done within a specific time frame. Click To Tweet
Remember: The definition of training density is a descriptive one, not a rationale of the benefits. Therefore, many coaches get lured into doing it simply because it exists and is an option to modulate sports preparation. Decreasing time while doing the same volume is a common approach to manipulating density, but during taper periods or recovery phases sometimes coaches do the opposite and pace slower.
We see a lot of training done in a short time period because it’s convenient financially, or it creates a feeling of hard work as the byproducts accumulate. Speaking of work, the term “work capacity” is thrown around when density increases, since it’s assumed that the merger of power training and short rest periods builds some resistance to fatigue later. The realities with all of the training density talk is that we don’t really know that much about the physiology of what it may do, but the empirical evidence is enough for coaches to value it and implement it in their training. Many coaches swear that training density has a benefit, while some scoff at it and some, like myself, still implement it but are cautiously optimistic about the impact.
How Much Research Is Available on Training Density?
I did a few searches and found an interesting suggestion by Dr. Brad Deweese and investigated the idea that training density creates a response worth programming. From the connected citation in his publication, the hope is that adding training density earlier in the season will create a benefit later, from a supercompensation effect. The reference was an article on tapering and overreaching, but the main variable was training volume changes, thus making it hard to tease out how to value or extrapolate the rationale of including density in training.
In a recent presentation at the CVASPS seminar, Bob Alejo from NC State mentioned the classic variable of training density, but very few people besides Ethan Reeve have narrowed down this concept as a focal point. While he has outlined his programming of density, I have never seen a direct connection, in the research or my own training, when decreasing rest periods impacted adaptations to qualities like power and speed. Endurance is another broad quality, but improving output and efficiency requires specificity and very few marathon coaches believe that reducing rest in weight training will result in better outcomes in a race later in the season. In fact, while training density is simple to see in weight training—especially in circuits—it’s not clear how different modalities boost or interfere with each other.
A fair conclusion with the principle of training density is that we know how to quantify it regarding work and time, but our understanding of how it helps us later is still murky. We can use lactate and heart rate readings to see how density modulation impacts physiology, but we need it to do something unique rather than just taking a few more minutes longer in a workout. Training density needs to show relevance like training volume and training intensity do, specifically with adaptations we can see show up later in the season.
Common Training Density Options in Training
By the very nature of what we know with the current science, density training is submaximal work and minimal rest. Rest-to-work ratios are usually simple options to try to increase or decrease density, but remember that density is not just about output and time. It’s also connected to volume and intensity, so it’s not as conveniently simple as using a pace clock and getting the work done.
The most popular option with density is to think about how much total body output you can do per minute or other measure of time. A circuit of arm exercises back-to-back with no rest is hardly the same total amount of work as snatching at 85% of ability with slightly shorter rest periods. Density is more complex than ratios or percentages really, so a simple yet powerful way to utilize training density is to make sure the common training options are easily adjusted.
- Body Circuits – Most programs incorporate a circuit-style session to get a lot of athletes moving and getting “work done” when time is at a premium. While this might be an efficient use of time, it’s not effective in getting athletes to improve their aerobic capacity or maximal strength and power. Circuits are a smart way to create a little biochemistry flux and help athletes with the dark mental drain of long seasons, but they are not going to improve absolute qualities.
- Accumulation Blocks – During early heavy training, athletes simply need more work. One way to get them this is to manipulate density instead of just adding more volume, and dropping intensity so more total work gets done. The problem with many block programs is simply that they require a lot of time and are not practical for most team sports. Athletes doing weightlifting and other Olympic sports have more time to prepare, as the season is about maximal performance versus entertainment schedules of the ball sports we’ve come to love. Adding density manipulation may help break staleness or throw a wrinkle into training by creating a more demanding session but with the same volume. While accumulation periods are known to have a simple rise in volume, the successive change gets boosted when both volume and density are modified later.
- Potentiation Options – I wrote about potentiation earlier, as I have seen a lot of videos with sloppy speed and exercise options strung together. French Contrast training, contrast, and complex work are all possible when athletes are elite. In general, density training is an element best reserved for advanced trainees, and potentiation options are similar. It’s better to focus on pure and absolute options like maximal strength or endurance rather than move too early to less impacting elements that can dilute either quality. Potentiation work is time-efficient, but it also takes a lot of time to recover from because the training elicits higher-than-normal outputs in strength qualities.
- Peaking Workouts – When athletes hit a ceiling, one element that some successful coaches use is just reducing rest between hard bouts of speed or power work. The reason for cutting rest between bouts during a peaking phase is that density increases the relative demand of the session while maintaining absolute intensity, which is a more stubborn variable to work with. Provided that the output is near maximal, many athletes do in fact rebound down the road, but some respond poorly to fatigue and just struggle to recover from the training. Coaches may want to experiment with similar workouts earlier to see which athletes may benefit and which athletes need to stay away from it.
Besides getting a workout over with more quickly, training density may help coaches find ways to safely overload without just adding more weight or requesting someone to raise their intensity. A word of caution: Rest reduction increases fatigue and can lead to technique decay. Injuries stemming from training density are unknown, but any effort to make things tougher without a clear goal is logically the bane of productivity. We often see garbage reps, sloppy runs, and a degradation of the technical model of performance when coaches focus on getting someone tired versus getting someone better.Rest reduction increases fatigue and leads to technique decay. Make the athlete better, not tired. Click To Tweet
A good mantra is to think about making more ketchup—meaning that it’s better to add more tomatoes than to add tomato juice and dilute the qualities of the athlete. Ironically, density training often reduces the density of absolute qualities when major biomotor abilities are not well-developed.
When and Where to Implement Training Density
With the common options in training reviewed above, a common question asked is when to add density to the program. To me, training density is an advanced variable for speed and strength training, but an introductory variable for general fitness when programmed properly. At first, it may seem strange that weight training has different rules than conditioning, but there are reasons for this conflicting perspective. First, conditioning is about familiar movements that have low loads, such as grass runs or higher rep exercises. Conditioning is, by nature, about endurance qualities and extending the duration of power, while power development is elevating the absolute ability of it. A natural conclusion is to focus on strength training maximally and use density for workouts that drive fitness.
The general training period and, if available, the specific training period as well, are the two periods I want training density with college athletes or those with a deep training age. The way that I evaluate training age is not by years or weeks of quality training, but by the results of training in comparison with their peers. It’s easy to give a black belt to a 10-year participant, but I would rather make evaluations in a competitive environment like a street fight.
I do like density work with in-season circuits with low intensities to create heat and sweat when the body and mind need a break from the drain of competing and even coaching. The trance-like effect of circuits and the pump from bodybuilding-like variables usually sparks a positive change with hardworking athletes who need a lift. Here are a few simple ways to sneak density into a program without compromising the main goals of training, while also using density for benefits outside of the theoretical physiological adaptations.
- Lack of Time – There comes a point when using time efficiently is a realistic need for density changes. When time is a scarcity, just using rest periods to get other work done or keeping the intervals a little shorter makes sense. On the other hand, it’s always better to drop volume and raise intensity, so don’t think that a lack of time means that you can only decrease rest. You can drop sets and reps and raise up the intensity too. If an athlete has no warmup or practice, especially in the morning, I prefer density modification. If an athlete is coming from a field session, I prefer to take advantage of the training and raise intensity, provided they are not exhausted. Some warmup sets can ward off risk, such as the Raptor test, but coaching experience is necessary when adding loads.
- Temperature – In cold weather and cold indoor facilities, an athlete will benefit from a little density to keep them warm and supple. A fine line exists—more narrow than I realized—between over- and under-heating the muscular system. Just as with a shortage of time, manage a shortage in temperature with the right rest period. This allows for great output and keeps the body hot by keeping the athletes moving. This is valuable to older athletes and speed and power athletes during heavy training periods.
- Focus – Too much idle time creates distractions. Many programs that allow for big rests open the door to poor attention to training. This is a very complicated problem because things can get too comfortable without balance. However, not allowing social connectivity makes training a punishment. It’s OK to have fun, but athletes and coaches should foster this outside of training as well. Circuits are social between trips or rounds, but during them it’s a well-oiled machine. Coaches can play with density to increase or decrease casual interaction in order to fit their own team or training philosophy.
- Teaching – Getting into a rhythm with repetition still works with athletes, even with all the hype that we see on motor learning gurus. Sometimes, shorter intervals in training force the athlete into the moment mentally with their movements, as long as the density of the workout doesn’t increase fatigue. Errors are often just manifestations of fatigue winning the duel between coordination and exhaustion, so know how to spot fatigue from drops in power versus just mistakes in motion.
- Strain – If an athlete needs to break a plateau to get better using an increase in density, it is worth experimenting with a barely perceivable. Challenging an athlete safely without increasing the absolute intensity and/or adding more volume can help drive a body out of a comfort zone regarding homeostasis. Depending on the length of time an athlete is stuck in a plateau, the solution is a short change or a longer phase of density work, as long as monitoring shows the athlete needs challenging and doesn’t have symptoms of overload or chronic overreaching.
Young athletes, such as high school athletes, need to focus on learning and training the basics. Many proponents of youth programs that incorporate paired weight training sets beyond two exercises place profit or convenience ahead of results. Repeated moderate loads will improve strength with neophytes, but learning to recruit more motor units neurologically requires rest for both recovery and instruction. Athletes are not widgets on an assembly line or fast food meals delivered in a drive-thru; each body is a piece of art that requires time and craftsmanship. Many coaches brag about the number of athletes they’ve trained, but like density, the quality of each athlete is far more important than sheer volume.
Measuring Training Density With Power and Conditioning
Similar to Repeat Sprint Ability (RSA), training density is more about intensity than how compressed the session or phase is. When you introduce a combined measurement, the primary absolute ability is essential and should be tested first. Many compromises to rest will actually reduce development to the training variable if the output is not sufficient.
For example, the research on soccer speed shows that training at 90% of velocity in sprinting seems to have no successful transfer later. If the velocity drops further from adding more density, the well-intended training decision may actually reduce the results from the previous season. This misses the point of the entire workout, which is to get better or maintain abilities. Intensity and then volume are always a priority over density qualities; therefore, the variable of decreasing rest for the sake of increasing demand is a selective option only when a quality is firmly in place.
After you measure the absolute work, no matter what the output is, the next question is, “When does density modulation make sense?”. Like intensity, volume is easy to measure, but determining the amount that someone should do is tricky. Fatigue is more difficult to quantify because multiple systems are at play. While an athlete could repeat a workout, doing so while compromised may turn non-functional overreaching into injury or similar.
The science is not clear on the connection between density and volume, but a good idea is to use familiar training loads and see how reducing rest maintains the output or slightly decreases it. A good working practice is to try to maintain effort and output, but reduce the rest just enough to see an RPE change or significant physiological effort in the recovery period between reps. Power is harder to evaluate than the outputs such as barbell velocity or jumping power, but it’s OK to use some metrics like HRV or even HR. Regardless of what you use to measure absolute performance and physiological recovery, time is the final part of the calculation and influences the scoring.
You should see all work as a pacing rate (per minute or per hour) or similar, but even this is too crude to have confidence that we hit payday when rating training density. Coaches sometimes need to consider other factors, like the entire session or training day, because analysis of just one part of a workout doesn’t give the entire story. A dense circuit at the end of an afternoon workout that included a midday nap and rest period is much different than a double with a one-hour lunch break.
Training density programming is not only limited to the workout session; the variable can be manipulated over the season and career of an athlete. As the athlete develops, training density can increase as absolute biomotor abilities increase, but all of this is optional. Coaches should look at simple patterns of hard sessions each week, lifts and sprints above their thresholds, and manage this with an understanding that it’s OK to get tired, provided that it creates a positive change down the road.
Evaluating the Adaptions of Training Density
The final step to implementing training density into a program is answering the question, “Was it worth it?” Athletes have three common patterns when training hard: risk of injury, risk of unnecessary fatigue, and working hard without getting improvement. Obviously, doing a routine that challenges the body does have value because today’s athletes are slightly coddled, but modern competitive schedules throw depleted athletes at performance coaches all too frequently. Adding density to get fitness from an athlete who is underprepared and overplayed is just lighting the fuse to a ticking time bomb.
What I have found useful is to see if the athlete can do more work without compromising the intensity or performance when compared to previous workouts. While this is difficult to evaluate because it would be hard to show long-term benefits over a career, it’s great to see if workouts with training density mean better injury resilience or testing scores.It’s better to develop a racehorse than to train an athlete to become a work horse. Click To Tweet
From time to time, training density reduction, which is even less talked about in coaching circles, is another way to calibrate training that might be a little too much for the athlete. This helps show if the tipping point was just a little too close for comfort. Cluster sets, which decrease the density for higher outputs or act like a mirror to potentiation by doing the opposite, add more rest between reps to increase the output. Non-responders to cluster training are usually too deep in overreaching to respond to the mechanism. Sometimes non-responders don’t do enough quality work, so those that succeed in training density workouts might not perform well later. It’s better to develop a racehorse than to train an athlete to become a work horse.
Straightforward testing of body speed (horizontal or vertical), ball speed, and bar speed can show if something might have worked. It’s hard to always look for direct causation, but because modern training programs have so many variables, if the scores drop at least you’ll know if something might not have worked. Also look to field or event performance to ensure an athlete is not winning the workout but losing the game, as sports preparation is about transfer.
Parting Thoughts on Training Density
A healthy perspective is to save training density programming until everything is in place and the athlete needs to advance, or as a creative solution to common challenges with training groups. Unfortunately, it is likely that programs that remove training density will see fresher and more explosive athletes in the future than those adding it. If used correctly, training density is a great addition to a program. However, it is not as powerful as more essential variables. The sensible use of training density can help polish a great program and, hopefully, these guidelines can help refine the process.