Applying the Principle of Variation to Tennis
In last week’s post, we took a closer look at the principle of progressive loading and offered several ways in which we can effectively ‘progress’ a player both on and off the tennis court. To reiterate last week's point, it’s critical that we look at progressions from a long-term macro perspective. Why so? Well, progress is rarely (if ever) linear. Further to that, each of the biomotor qualities that we spoke briefly about last week (speed, strength, stamina, suppleness, skill), improve and regress, depending on which we give greater attention to (i.e. more training stimuli).
Here's an example that illustrates this point. Let’s say we want a player to increase the intensity of their training sessions. For simplicity’s sake, let’s say they are training 2 hours a day, 6 days a week. Because we want them to increase their intensity, that’s exactly what we demand of them - using the SAME training scheme from one day to the next. Each day, there is greater effort and attention to increase their explosiveness to the ball, their rotational power on groundies or greater intent on their recovery movements. Would this approach seem logical? Perhaps it would work for the first 2-3 days but you know what would happen next - they’d either begin to show signs of fatigue OR the stimulus wouldn’t have the same effect. As complex biological systems, we are just unable to sustain continued, steady increases in load/intensity. This is where our next training principle comes into play, variation.
This week’s post will take a closer look at variation and offer ways in which on and off court training can be varied - the aim being to continue improving over the LONG-TERM while avoiding stagnation.
The Principle of Variation
Definitions
Variation essentially means the manipulation of various training variables - i.e. adding variety - or a different training stimulus. This can be done in different ways. One can change an exercise (or use a derivative of an existing exercise), manipulate load, volume (reps, sets), ROM and speed of movement (all of which we covered in last week’s post). Furthermore, variation can also signify the degree to which different training means are manipulated throughout the programs of elite athletes (i.e. the proportion of time spent doing sport-specific work - tennis - versus off-court means like elastic strength, speed-strength etc.). Stone et al (2003) states that variation is important for the “prolongation of adaptations over continuous training programs”. Let’s explore this a little further.
Firstly, sport scientists propose that a training stimulus will no longer elicit the same response if it is applied over and over. In other words, at a certain point, the body adapts to the stimulus and we must vary one, or many, variables. Applying a constant training stimulus over a long period of time, will likely result in what’s referred to as ‘stagnation’. Secondly, while periodization/planning have been under scrutiny of late, empirical and anecdotal observations continue to suggest that it’s this variation in training that produces the most effective performance results over the long run.
A Brief Look at the Interplay Between Variation and Specificity
Variation and another training principle, specificity (which we’ll cover in another post), have been said to be a “trade-off between the conflicting demands for fluctuation versus stability” (Zatsiorsky 1995). In other words, too much specificity, and an athlete might stagnate, reach a plateau and/or suffer a repetitive/overuse injury. Think of a player who performs the same cross-court drill over and over. While this drill is important, changing subtleties - movement/recovery requirements, attentional foci or ball speed/direction demands - can be enough of a variation in training stimuli to elicit an adaptive response.
In contrast, when looking at training from the opposite end of the spectrum, too much variety in training likely won’t provide the athlete with a chance to accommodate - in other words, there’s just too much diversity in training for an appropriate adaptation to manifest itself. Think of any training component - when we perform it once and then move on to something else, should we really expect a change in performance? I wouldn’t count on it.
A final point on the theory aspect of variation. Remember the dynamic systems theory? If not, check out this post and this post to learn more. One component of this theory that has relevance here is that biological systems are always undergoing change - we are in essence, never the same as we were yesterday, the week before, last year and so on. Are cells are in constant turnover - we’re essentially a new person! Let’s apply this concept to training for a moment. While we continue to adapt and change (as a result of both genetic and environmental factors), the same exercise or drill, for instance, is not really the same. If I’ve improved the mechanics of a squat, I now have different recruitment patterns when squatting - this in itself is a form of variation. Pardon my philosophical rant for a moment - this concept is still a work in progress but something to think about during the long-term training process.
Applying Variation to Training
If you recall from last week’s post, the principle of progressive loading states that, on a macro level, when we provide a greater training stimulus, we essentially ‘progress’ various biomotor abilities. The key here being that this is done on a ‘macro’ level. Adding variation to training allows us to continue loading over a long-period of time (years of training). Let’s explore this in 3 key areas, intensity, volume and exercise/drill selection.
Matveyev's Classic Periodization Model - While this graph presents an example of the manipulation of volume and intensity of training, many modern day coaches agree that it's too simplisitc to reflect the training of sport today.
Intensity
There are many different ways that we can use intensity to progress a player’s performance. For instance, when doing jumps, short sprints, change-of-direction drills and so on, we can begin with lower intensities of effort - i.e. asking the athlete to jump at 75% intensity instead of 100%. Why would we do this, you may ask? Here are a couple of reasons - first, going full out every time we train is demanding and taxing; sustaining this amount of effort over long periods of time is impossible. Secondly, performing exercises and drills at submaximal intensities still enable athletes to improve. Elite sprint coaches often prescribe sprint drills that are submaximal in intensity….and their athletes still get faster! Lastly, working at submax intensities leaves room for growth - increasing it over time. The most effective approach - according to research (Plisk and Stone 2003) and practice is to vary intensities.
A similar story exists with on-court tennis play. Do we ALWAYS have to hit groundies with full out intensity to improve? I’d argue NO! I’ve seen it firsthand with some of the best juniors and pros in the world. While working with a WTA player, some practice sessions we’re intentionally prescribed at lower intensities of hitting. In academy settings, my colleagues and I have done the same. In preparation blocks we’d often prescribe 70-80% hitting loads. At slower speeds, certain mechanical deficiencies can be targeted that may, in the long-term, result in increases in efficiency, speed of execution and so on.
Volume
Similar to intensity, high volumes of work are not always necessary for improvements to occur. Add to that the fact that volume and intensity are highly related. Elite players cannot sustain high volumes of work at high intensities for very long. This is where coaches can manipulate either or both, on micro and macro level. Various schools of thought exist on this topic. Elite coaches from a variety of sports have had success by manipulating only intensity, and keeping volumes high. On the tennis court, that would mean keeping practices consistently at 90 minutes in duration, for instance, but varying the intensity of these sessions.
Others, on the other hand, have done the contrary; varying volume but keeping intensities high. This strategy might be most appropriate the days and weeks leading up to a tournament - a coach keeps the intensity of practices high (so that players are training/playing practice points at conditions that closely mimick matches) but manipulating the duration of these practices - shorter and shorter as the tournament approaches. Both strategies likely have their place at different times of the year, with different athletes (principle of individualization) and at different developmental levels. One thing is common, however, is that this variance in volume and intensity is crucial to manage an athlete’s fatigue, energy and fitness levels - the aim being to optimize competitive readiness.
While it is out of the scope of this post to highlight the various volume/intensity schemes that are use in world-class training environments, there is both an art and a science to the variation of these 2 critical variables.
Exercise/Drill Selection
The last variable I’d like to tackle when it comes to variety is the manipulation of exercises and drills. While we touched on this briefly in an earlier section of this post, I’d like to highlight it in a bit more detail. In the gym, like we mentioned previously, exercises can be progressed in terms of complexity but can also be replaced by other exercises altogether. This is generally thought to be done once the exercise in question is no longer providing the desired stimulus. Changing exercises every week or even every 3-4 week cycle, likely isn’t always necessary. It’s simply too short of a time frame for the athlete to both accommodate and stabilize the quality that’s being trained. Tennis practices can take cues from this principle by sticking to drills over lengthier times - often we as coaches (I’ve been often a culprit of this) think a player ‘got it’, so we move on to another aspect of their game...and then we scream internally when the same mistakes begin to creep up.
Furthermore, when a player makes progress (primarily through training), the same exercise is no longer the same because we have a different physical makeup. We used a squat example to illustrate this point earlier, but the same can be said in tennis. If I’ve improved a player’s forehand technique, a cross-court drill is now slightly varied (because the player is him/herself different). If they’ve also improved their physical capacities, the drill takes on even more variation. This again, is something to consider when working long-term with an athlete.
Lastly, a drill, exercise or training component needs to be revisited regularly, not only over the course of a training cycle or year but over longer periods as well. When I asked a mentor of mine, a leader in the field of sport performance, what his thoughts were on Roger Federer’s continued success (he has ties with Roger’s team) here’s what he had to say, as it relates to this topic:
“He was grounded in sound and essential fundamentals and skills as a youth. These were evolved and mandated as he progressed as a professional. They always revisit these factors in a systematic way throughout the season and year.”
Final Thoughts and Still To Come
In tennis, there are many other ways the principle of variation can be applied. A coach can increase the speed and/or spin of the receiving ball, they can manipulate the surface or play against varying skill levels and game types. While these are a few examples, they are by no means the only. What's important though, is that we understand when we're applying the principle of variation as it can dramatically affect the training response. Like Fed (and 'm guessing all the greats for that matter - from Serena and Sharapova to Rafa and Novak), we should be varying and manipulating training means in a systematic manner; while we cannot control every variable, understandin their interplay is of paramount importance.
In future posts, we'll examine two other training principles - specificity and individualization - and offer links between them and the concepts I've attempted to tackle in the previous two posts. My hope is that knowledge of these principles encourages coaches and players to think critically about the design and implementation of both their on-court and off-court training plans.