Previously in my ‘The Body in Swimming’ series, I wrote a description of the Adenosine triphosphate-creatine phosphate (ATP-CP) energy system. In this post, I would like to revise some of the descriptions I made and also, would like to include a component of stored energy I have not initially mentioned which is recognised as playing a significant role in energy provision of swimming events over recent years.
Firstly, I would like to remind you about the comments made regarding the duration of the ATP-CP system i.e. how long it could sustain energy production. In the previous article is was stated that “Although the rebuild process can be completed extremely fast, the drawback is that is can only be used for approximately 4-5 seconds of max effort (di Prampero 1971). Therefore, a maximum rate of muscular contraction can only last for 4 to 6 secs.” Since writing the article, I have delved further into the evidence and have come to conclude that the above statement (and previous article) was wrongly generalised i.e. compared to other sports rather than specific to swimming. There are some factors which were not included, and their implications have caused me to revise the description.
Understating the ATP-CP system
It was concluded in the previous post that “time would be better spent developing other areas,” rather than dedicating training to seek improvements in the ATP-CP system alone. However, I feel I understated the importance of this system within a race and will set out to describe why I feel it is not an element that, in combination with another ‘stored’ energy source (which will be described below), should not be ignored.
Swimming, unlike various other sports, has a partially supported nature (totally supported in open water swimming), through the forces the body is acted upon in the water. As the body does not require as much energy to ‘fight’ against gravity and maintain posture, it is wrong to generalise the duration of ATP-CP use across all sports. Since the traditionally determined time of 4-6 seconds concerned sports of an unsupported nature, it would be rightly suggested that in swimming this provision is of greater duration – which has been approximated at 10 seconds. Also of importance is the phenomenon which occurs in cyclic sports such as swimming i.e. a propulsive phase and recovery phase following occurs; which allows for restoration of some of the creatine-phosphate as parts of the body go through the recovery period in the stroke.
The ‘stored’ energy source I referred to in the first paragraph is the stored oxygen within our muscles and circulation. Myoglobin present in the former and haemoglobin in the latter, are proteins which combine with oxygen and act as a readily available source of oxygen for the exertion of high-intensity. This stored oxygen source, in combination with the ATP-CP system, plays a significant role in energy provision of swimming events – which has not been previously recognised. Not only is it involved in the initial stages of exertion, but it is also partially restored during recovery phases of a swimming stroke – as with the ATP-CP system.
Fast-Component of the Aerobic System
To understand the importance of the ATP-CP, in combination with the stored oxygen capacity, knowledge of the ‘fast-component’ of the aerobic system is necessary. This area of the aerobic system involves the restoration of the two named systems during and after swimming exercise. The partial recovery phenomenon has already been discussed. Complete recovery of the ATP-CP and stored oxygen occurs after approximately 30 seconds post total-body exercise – even if different parts of the body have experienced different intensities.
Recent research has endeavoured to identify the importance of this fast component (during and after total-body exercise). In 2009, Alves et al., found that only VO2 max and the fast component correlated with 400m performance; Reis et al., also found this similar result. Fernandes et al. (2010) showed that only the fast component was related to performance in 200m performance. Thus, the ability to restore the ATP-CP and stored oxygen – partially, during exercise and completely, post exercise – is directly related to performance up to 400m. Due to the similarities in aerobic and anaerobic use in the 400, 800 and 1500m events, it can be hypothesised that this component is also significant at these distances; however, further research is required to confirm this.
The implication of the above is that traditional training, which does not adapt to the fast component of the aerobic system, is ineffective in optimally improving performance. Indeed, this is substantial justification for a completely different emphasis in competitive swim training programmes.
To conclude, this article has revised the previously generalised and incomplete knowledge of the ATP-CP system and has provided an explanation for greater emphasis on training which will adapt the fast component recovery of the aerobic system i.e. restoration of stored oxygen and ATP-CP.
It is suggested in this article that traditionally emphasised training of the lactate system is wrongly placed in improving performance and I will ensure my next article delves into this further. I will also attempt in the future to discuss training methods which aim to improve this fast component and identify the other important energy provisions in a swimming race.
Yours in Swimming,