There are two approaches to cardiovascular conditioning which can be taken, 1) the specific training of each individual energy system or 2) ‘fuel mix’ drills. Fuel mix drills can be seen as a very sport specific mix of intensities designed to mimic the demands of a particular event. Playing the sport itself would be the most sports specific fuel mix drill available but this is not always practical.

A wrestler, for example, is required to tolerate huge amounts of lactate and hence their training will reflect that. It should be evident that to achieve this through daily, intense sparring work on the mat would be highly impractical and as such, this will need to be topped up with gym based work. Practicality is not the only drawback to such drills though.

Whilst a fuel mix, mimicking approach will potentially deliver the most sports specific benefits, the intensity will likely be too great to perform on a daily basis without pushing the athlete towards an overtrained state. Also such an approach is more difficult to control in terms of delivering a specific physiological outcome.


An interval approach, whilst limited in terms of specific development of cardiovascular conditioning for wrestling, would allow you, if tailored correctly, to enhance one particular energy system. The fuel mix drills, though, would enhance your ability to switch in between the various systems efficiently.

Figures 1 and 2 show the heart rate traces for two scenarios; fig 1 shows the heart rate of an athlete engaging in a run of moderate intensity for about 10 minutes and fig 2, taken from my days working in boxing, shows that of a boxer sparring three rounds. Anyone simply eyeballing these two traces can surely see the futility of boxers basing their CV training around slow, long runs sadly the boxer’s traditional, staple method.

The two are so clearly different. The long run shows lower peak heart rates (up to 20pm lower), no burst recovery nature and nothing challenging to any energy system other than the aerobic – they are simply so unalike. This is exactly the same pattern you would see in football, tennis, rugby, tennis etc.

Training of metabolic pathways

Aerobic base

Some coaches and athletes believe establishing an aerobic base during the early stages of a training cycle will be of benefit. In essence, if a athlete is able to increase say, distance covered in a 60 minute run by 30%, or work for 30% longer at a given running pace, then this will act as a strong foundation from which to add in periods of increasing intensity (specific interval training) as they get closer and closer to the start of a season, big fight or major competition.

In a four month preparation cycle, perhaps the first month will be mainly comprised of longer, steady state activity. I am personally more convinced of the benefit of this type of training in sports where the athlete is forced to work non-stop for extended periods, e.g. rugby, football, hockey etc.

In sports with a round system, i.e. periods of intense effort interspersed with periods of complete rest such as boxing, MMA and racket sports, I am less convinced as to the relevance of this type of training in this exact form.

Lactate tolerance and lactate threshold

One of the key concepts, as has already been observed, is the importance of the athlete’s ability to work at higher intensities before there is a systematic build-up of lactate in the blood – termed the ‘anaerobic threshold.’ With anaerobic threshold training, an athlete would be able to continue to work aerobically at higher levels of intensity before the build up of fatiguing lactate took place.

In order to train an athlete’s lactate threshold they need to be working in and around their lactate threshold during an interval training session. Of course most athletes don’t have access to sports science support which would enable them to find out at exactly what heart rate and intensity level their specific lactate threshold occurs.

There is, however, a pretty reliable, indirect test which you can conduct using a treadmill and a decent heart rate monitor which is able to record data and upload to a PC. The protocol for this ‘Conconi Test’ is as follows:

Conducting the Conconi Test

• Perform a five to ten minute light warm up programe
• Set the heart rate monitor to record at 5 second intervals
• Start the treadmill at a comfortable jogging pace
• Increase the treadmill speed every 200 metres by 0.5km/hr
• End the test when you have reached your maximum heart rate or you can continue no longer • Stop the heart rate monitor recording
• Perform a 10 minute cool down

Left is an example of the graph generated during this test. We can determine anaerobic threshold by the point of inflection of the line.
Now we know the athlete’s anaerobic threshold we can develop a training programme around this. Generally speaking, LT/AT training involves interval training bouncing from just below to slightly above LT/AT.

The build up of lactate (i.e. ‘the burn’) should be less severe than in lactate tolerance training (see below) because, as Eric Lawson states in ‘High Performance Sports Conditioning,’ “To improve a particular function, that function must be stressed but not overstressed. ‘Comfortably hard’ is a good, subjective way to describe threshold pace.”

Numerous studies exist to highlight the importance of anaerobic training but a good example which I found particularly convincing for coaches during my time working with boxers was a 2002 study which found the physiological variable most related to boxing success was the anaerobic threshold of the fighter. Indeed, it was found to be significantly more important than maximum aerobic capacity (termed VO2max).

The goal of lactate tolerance training is not necessarily to enhance LT/AT but to train the athlete to cope with and tolerate the discomfort associated with the unavoidable build up of lactate which will occur during a sporting contest.

Colloquially speaking, it teaches you to grin and bear it. With lactate tolerance training the goal is to train for relatively extended periods above LT/AT, with high levels of lactate accumulating.

• You will see recommendations in books but the best way to judge is by how you feel.
• Work at near max for 45-90sec and you should begin to feel the burn of the lactic acid in the muscles.
• Work for as long as possible before a drop in intensity would be required. When you feel you would need to slow down, stop and recover instead.
• Take only enough rest and recovery to permit a similar effort.
• Four to six repeats over one to three sets is recommended.
• Progression can be in the form of more reps, more sets, higher workrate, a longer period at the same workrate or shorter rest intervals. Just be aware of keeping the intensity level high.
• One, at most two, of these sessions per week is enough.

Phosphate system

Shorter intervals will stress the phosphate systems and thus will enhance stores of and the ability to replenish Creatine Phosphate (CP) and ATP. Resistance training and short sprints, 50-150m, with long recovery periods would stress this system effectively.

The longer rest periods would prevent excessive build up of lactate, which stops the session turning more into one of lactate threshold or tolerance, and provides adequate time for the phosphates to be resynthesised. Phosphate replenishments times are as follows

A phosphate systems training protocol might be something like six 75m repeats with around 2 minutes of recovery in between sprints (resulting in a work:rest ratio of about 1:12 in this case).

Fuel mix conditioning drills

Fuel mix conditioning drills are designed to stress and train every (or at least multiple) energy systems and in a fashion which most closely mimics an actual, competitive contest. As noted previously, in many sports there are times when you rest completely, times when you take a little breather, times when you are active at lower levels and times when you go all out.

As such they involve a very complex interplay between the various energy systems; a complex interplay which the approach highlighted above does not adequately address. Surely it is as much a athlete’s ability to effectively switch between these energy system which must be trained as it is the training of the systems themselves.

Playing the sport could be considered the ‘perfect’ fuel mix drill, with sparring and competitive simulations in training coming a close second. However for reasons of practicalities we often use drills and interval training in addition. One must, however, address the specificity of the exercise forms used.

Any sport clearly involves very specific and unique movement patterns and this has to be borne in mind when engaging in aerobic conditioning. Emphasising the importance of specificity of exercise type, a 1975 study showed that following a period of swim training, swimming VO2max increased by 11.2% but running VO2max increased by only 1.5%.

A study utilising cycling training showed similar results. As such, when developing an effective cardiovascular conditioning programme the modality of exercise used must, as often as possible, replicate the movement patterns involved in the sport.Would you imagine Bradley Wiggins spends most of his time on a running track or on his bike?

When constructing fuel mix drills it is vital that we always take into consideration the demands of the event. If we consider boxing as a convenient example we have a work to recovery ratio 3:1 and, as noted within each round the intensity dramatically fluctuates.

Furthermore, the total bout length ranges from 11 minutes (amateur) to a maximum of 47 minutes (championship professional). We discussed aerobic base training earlier, but I prefer to talk in terms of specific aerobic base or fuel mix aerobic base training. Consider a boxer preparing for a six round contest.

Running six hard repeats of around 1000m (approx. 3mins) with one minute recovery will enhance the fighter’s ability to cope with the aerobic demands facing them. It will develop an aerobic base specific to boxing. It will also, however, fail to address the fluctuation of intensity within rounds, which is why more specific, fluctuating fuel mix drills or higher intensity, shorter duration intervals will also be necessary, perhaps, as a key fight approaches.

A more developed example may be to set up a series of signs around a track saying things like ‘jog,’ ‘run,’ ‘sprint’ or ‘40%,’ ‘50%,’ ‘70%’ ‘90%’ and ‘100%’ distributed randomly. Obviously the athlete shifts their intensity according to the placard they are passing. Sport specific fuel mix drills can be constructed very easily using this approach.

Furthermore, intensities can be fluctuated by utilising fewer higher percentage placards and vice versa. However, be aware of ‘100%’ everywhere; then it just becomes running 1000m as hard as you can, what I previous termed specific aerobic base. The athlete’s average intensity is high but this approach never permits them to all out sprint at any point.

It can also be utilised to bring about certain intervals and thus target specific energy systems as discussed previously. How about a fuel mix/interval session constructed of explosive lifting exercises? We could start with our athlete performing a sequence of power shrug, clean pull from the hang, power clean from hang and split jerk, repeated for one minute, for four sets and with, say, a couple of minutes rest and recovery in between sets.

We could increase or decrease the rest period, increase or decrease the weight used, increase or decrease the set length, increase or decrease the number of sets. As you should now understand, more isn’t always better. Less rest and recovery and longer sets will prepare you aerobically more effectively, but will prevent you working at a higher level of pure intensity.

It would probably be advisable to mix up the various sessions, as well as integrating sessions from time to time which don’t massively drain the athlete. Rest and recovery is vital and no athlete can work at 100% of their physical capacity every session without breaking down.

Wouldn’t it be impressive, though, if, for example, a boxer, was able to perform the suggested explosive exercise complex with a challenging weight, for 12 sets of three minutes and with a one minute recovery period between sets, whilst also maintaining a high level of performance throughout? Would that not be phenomenal preparation for that boxer?

This article will hopefully make you consider and question the most appropriate methods of cardiovascular conditioning for all athletes outside of those in largely steady state sports. There are merits to both approaches discussed here and the two can probably sit together quite comfortably in a conditioning programme.

Some coaches like to utilise development of specific energy systems as a base and then build on these during later stages with fuel mix drills; it may be a good approach. A key take-home message, though, is that sticking with one method all the time will probably not deliver success, the metabolic system is far more complex than that.

Mixing and matching of intensities and methods is a far better approach and don’t forget that training at maximum capacity all the time wi likely result in overtraining. A good approach may be to work in three day cycles in which the athlete performs one very hard session, one moderate session and one light recovery session.

Once or twice a week throw in a day off comprising of mental restitution, massage etc. With all of that still borne in mind, as the season or contest approaches an athlete must engage in the most specific forms of training, i.e. intense competition of simulations of it and fuel mix drills designed to most specifically mimic the upcoming contests.

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