A Quick Review The human body can produce energy in one of three ways; two of these pathways are "anaerobic" in nature (i.e. not requiring oxygen for energy metabolism), the third - the aerobic - produces energy at a much slower rate but for extended periods of time in the presence of oxygen. One of the most fundamental mistakes made by coaches and athletes alike when training for competition is that they look at these different energy systems in isolation. The fact of the matter is that each of these systems work in concert with one another, rather than in a mutually exclusive manner. The task of a well prepared coach is to understand the energy demands of his/her athletes' event, coupled with their athletes' specific strengths and weaknesses and train to prepare the athletes for that particular event by training the energy systems in an appropriate manner to optimise performance. Knowing the demands of the sport/event alone is not enough. The coach must also have an intimate understanding of his/her athletes' physiological and psychological make-up to enable appropriate training loads to be set. For the sake of simplicity let's look at training advances from aerobic and anaerobic perspectives and then see how to integrate the whole process. Training Loads For years physiologists believed that athletes either trained aerobically (i.e. Less than individual anaerobic threshold "I.A.T.") or anaerobically (i.e. Higher than I.A.T.). More recent research has shown that there are five distinct exercise intensities that evoke specific physiological responses in athletes: Level One Exercise Intensity (L1): The athlete exercises at 70-75% of the I.A.T. heart rate. This training is designed as "active recovery" to help flush waste metabolites from the working musculature after competition or a hard training session and stimulate the delivery of fresh, oxygenated blood and nutrients back to the fatigued muscles. Such a training intensity typically produces a blood lactate concentration of between 0.5 to 1.5 mM. Level Two Exercise Intensity (L2): Here the athlete exercises at 80-85% of I.A.T. heart rate. This type of training load is designed to stimulate "peripheral cardiovascular fitness" by increasing muscular capillarization, increasing the concentration of aerobic enzymes, improving fat metabolism, increasing glycogen storage capacity, increasing the concentration of mitochondria (i.e. Aerobic energy houses) within the trained muscles and as such, eventually, allowing the athlete to stay aerobic at higher workloads than could be achieved previously. Such training typically evokes blood lactate concentrations of 2-3 mM. Level Three Exercise Intensity (L3): Here the athlete works at 95-100% of I.A.T. heart rate and the training is designed to stimulate the "central" component of the cardiovascular fitness equation by increasing lactate production to the point at which the rate of production is matched by clearance. Research has shown consistently that training at the "anaerobic threshold" has the most significant effect on increasing cardiovascular fitness. Here lactate concentrations are within the range of 4-7 mM. Level Four Exercise Intensity (L4): The athlete exceeds the I.A.T. (i.e. 105%+ of I.A.T. heart rate) and takes lactate production beyond that which can be comfortably cleared to sustain the same exercise intensity. Here the athlete works at levels which exceed their ability to clear the produced lactate. As a result lactic acid begins to accumulate eventually forcing the athlete to slow down in order to dissipate this by-product of anaerobic metabolism. By doing a certain limited amount of weekly training at this intensity the athlete enhances his/her ability to "tolerate" this lactic acid load before being forced to decrease exercise intensity (i.e. slow down). By raising lactate loads to maximal or near maximal concentrations the athlete enhances their ability to metabolise this metabolite thus enhancing central cardiovascular fitness as 75% of lactate produced is metabolised by cardiac muscle. During this form of training blood lactate concentrations should be close to maximal. Level Five Exercise Intensity (L5): The ATP-PC, or instantly available energy system within the muscles (i.e. The alactic energy system) is the central focus of this training intensity. The ATP-PC system provides great concentrations of energy quickly, as the energy is stored within the muscles, however this energy source is very quickly exhausted (within 8-15 seconds). It is important that aerobic based athletes (e.g. triathletes) maintain this energy system as it will be drawn upon in competition (e.g. Surging out of the saddle on the bike to clear a small hill without losing one's momentum). If the system's not trained the athlete wont be able to call upon it effectively during competition. Research has shown that by working at different exercise intensities different physiological responses can be evoked. The mistake often made by many aerobic based endurance sport athletes is that they train or race too hard too often. Sending the body beyond the I.A.T. (or L3 exercise intensity) too frequently actually has detrimental effects upon aerobic metabolism (i.e. High concentrations of lactic acid actually decrease fat metabolism, adversely effecting cellular membrane integrity and aerobic enzyme function). Therefore a fine balance must be struck between enough "quality" work to increase I.A.T. and too much which will suppress aerobic function and often result in chronic fatigue. For example, a mature triathlete preparing for an upcoming ironman in six months may structure their run training routine in the following manner: Base Training Phase: 3 months: 140-160 kilometres per week. Exercise intensity L1 30% L2 60% L3 10% L4 0% L5 0% Intermediate Training Phase: 2 months: 120-140 kilometres per week. Exercise intensity L1 20% L2 50% L3 20% L4 10% L5 0% Peak Training Phase: 1 month: 80-100 kilometres per week. Exercise intensity L1 25% L2 40% L3 15% L4 15% L5 5% Here all three energy systems are stressed over the duration of the training rotation. The triathlete first builds a comprehensive aerobic base before stressing the glycolytic and finally the alactic systems. As competition approaches exercise volume is traded for exercise intensity and the triathlete does a lesser volume of work but at a higher intensity allowing increased time for passive recovery. Relatively recent work by respected South African sports physiologist Professor Tim Noakes suggests that fatigue in endurance based sports isn't entirely the result of depleted glycogen stores, particularly in running. Noakes believes in many cases fatigue in the "elastic properties" of the connective tissues actually precedes glycogen depletion and the athlete is forced to slow because of a loss in muscular integrity rather than the exhaustion of fuel stores. This is particularly so in cases in which the activity has a large eccentric muscular contraction component such as is the case in running. To combat this fatigue and increase the athlete's resilience, incorporating some specific eccentric muscle load training will help (e.g. Running downhill in training when fatigued). Note that this is relatively extreme training and should only be incorporated into the training programs of highly trained elite athletes who have exhausted other conventional training practices and are looking for a "competitive edge". Such eccentric work is thwart with the possibility of injury not to mention muscular pain and discomfort. The Australian Institute of Sport (A.I.S.) Over the last four years have also been experimenting with heat stress training and altitude training as methods of improving aerobic performance. Whilst the results are far from conclusive the preliminary data certainly looks promising. In summary: I.Heat stress training has been shown to: (a) Increase plasma volume which has the corresponding effect of decreasing blood viscosity (thickness) and therefore improving blood flow through capillary beds and as such oxygen and nutrient supply to working musculature and (b) speeding the production and turn over of new red blood cells (RBC). II. Preliminary data on altitude training for sea level performance suggests the following: (a) Athletes should use altitude exposure, within the vicinity of 2400 metres, during the base, preparatory stages of training to improve peripheral cardiovascular function. Here exercise should be of a low intensity for a period of approximately 4 weeks. As a result of other confounding factors (e.g. Muscular atrophy, dehydration, etc.) that are often associated with long periods of exposure to altitude, athletes need to be closely monitored. (b) As the athlete gets closer to competition, high intensity training/racing is best completed at lower altitudes so as to simulate loads and neural innervation patterns. To maintain the hypoxic (lack of oxygen) effect the athletes can be transported back to altitude to sleep which will maintain the EPO (RBC stimulating hormone) response. (c) There is some belief that exposing athletes to altitude for 48-72 hours coupled with light aerobic exercise will increase EPO production which will result in increased RBC production and an enhanced oxygen carrying capacity. Whilst empirical investigations are yet to show consistently improved performance with this practice, the theory behind it is sound and increased EPO concentrations have been found from short term hypoxic exposure. Anaerobic Training In relatively recent times the neurological or nervous system component of strength training has become more and more apparent. Athletes involved in strength training programs for the first time, or after a lengthy break, show remarkable increases in strength and power within a couple of training sessions. Where does this increased strength come from? From an enhancement in the neurological pathway "innervating" or "turning on" the specific motor units or groups of muscle fibres. This is of particular interest for those athletes requiring explosive strength/power without the associated adverse effects of increased muscle bulk (e.g. In aesthetic sports such as gymnastics or diving, or weight dependent sports like boxing, judo or wrestling). During the final specific build up to key competitions coaches can incorporate specific strength/power activities in the weight room involving specific musculature in particular movement patterns that are similar to what the athlete is likely to experience in competition. In this manner the athlete gains functional, specific strength/power in those muscle fibres required during competition by exercising those muscle fibres in a controlled fashion and without the likelihood of damage that may occur in the field (e.g. A triathlete that may have a major competition coming up over an undulating to hilly bike course that requires explosive power to clear some of the short, sharp climbs. He or she can: (a) Do all their training in a big gear and sprint over the hills which is highly specific, but also dangerous from an overuse injury perspective, or (b) do some percentage of their training in this manner and supplement the balance with some highly specific movements in the controlled environment of the weight room (e.g. Leg press through a partial range of motion)). Following the 1992 summer Olympic Games in Barcelona, Spain there has been an increasing level of interest in the use of creatine supplementation. Once again, the theory of increasing creatine levels within trained muscle for improved performance in activities requiring explosive power is sound. In fact, "creatine loading" is nothing new and some of the early investigations date back to the 1960's with the famous Swedish exercise physiologists; Hultman and Bergstrom who pioneered the concept of "carbo-loading" for endurance performance. Recent research suggests that there may be some benefits for power athletes (i.e. Throwers and sprinters) to supplement with creatine. Additionally, studies have also shown that athletes involved in sports which have a high intensity component followed by a short rest period before another "effort" (e.g. Mountain bike riders or Grand Prix style triathletes), may benefit from creatine supplementation, as increased concentrations of creatine may help to "buffer" the acid component of lactic acid in much the same way as sodium bicarbonate loading has been shown to work. The jury however on creatine