In this article we look further at the principles governing performance in swimming in the light of the specific requirements of open water swimming. Clearly, open water involves a range of swimming conditions and demands that differ from pool swimming. Conditions in open water may range from those of a 'glass-like' fresh water lake to a swirling mass of waves off the beach, to swimming on your own or tightly positioned in a pack of competitors. The degree of choppiness of the water may change with wind strength and tidal movements. Courses may be point to point, or around a set course navigated by buoys that need to be rounded. In many ways, swimming in open water requires a variety of skills that can be very different from swimming in a pool. In fact, a given swimmer needs to adapt a range of skills to different race conditions. Swimmers even need to modify their swimming technique within a race such as when negotiating a triangular shaped course where the wind and swell may be in the direction of swimmers in one leg, but against and/or to different sides in the others segments. Thus, swimmers need a technique that is not only adapted generically to open water swimming but also need to be skilled at adapting that technique to suit the conditions. This is very different from the case of pool swimmers who refine their techniques to be very consistent because the environment they race in is standardised. From our personal experiences as a veteran surf swimmer and triathlete (respectively), the relationship between pool swimming and open water swimming ability appears to be 'strong' but not 'very strong'. For example, the first author had a training partner who had similar speed in still water but was clearly superior at taking advantage of a following chop in rough seas. In contrast, the first author was faster in choppy water, particularly when the chop was coming from the side, than some members of the training group who could maintain a faster pace in a smooth water environment. Many very strong pool swimmers find it harder to be competitive in the open water, without having to modify their strokes somewhat. In the previous paper it was recognised that sustainable speed was related to the ability to maximise propulsion, the ability to minimise resistance, and the ability to do these in ways that are physiologically economical. Principles relating to each of those areas were discussed. In this paper we consider the principles in the light of the demands imposed by open water swimming and the implications for adapting technique to suit those conditions. Content: - Introduction - Maximising Propulsion - Minimising Resistance - Maximising Economy - Summary of Main Tips for Open Water Swimming Summary of Main Tips for Open Water Swimming: When swimming in choppy conditions other than when the chop is coming from behind, the motion of the recovery arm may need to be 'rounder' and enter further in front of the body. When the chop is coming from behind a long glide can be used with a pull and kick timed to 'ride the wave'. In highly turbulent water, it may be necessary to 'search' for some non-disturbed water outside of the 'normal' stroke pattern, by going wider or deeper. If the water near the surface is turbulent then effective forces may be produced later in the stroke than when swimming in smooth conditions. This may involve 'pushing' harder than usual just prior to exit. The swimmer needs to develop patterns of neuromuscular coordination to suit the conditions. Being able to breathe bilaterally provides an advantage by being able to breath comfortably to the side away from the chop thereby avoiding excessive body roll, minimising disruption to technique, and swallowing much less water! Good core stability helps to maintain good body alignment in roguh conditions and turbulence. Practising in a range of open water conditions helps enables successful adaptation to any conditions in open-water competition. Muscles that are not used or are used minimally in flat-water swimming may be used to compensate for perturbations in open water swimming so that good alignment is maintained. The strength and endurance of muscles required for the specific demands of open water swimming is probably best developed by training in those conditions. The ability to 'swim straight', independent of the breathing side, is an important skill. Similarly, good technique in sighting the course buoys or landmarks is crucial. Minimising the disruption to the normal stroke pattern and optimal body position will help with average swim speed. Hence being able to couple a breath with the sighting manoeuvre is an added advantage, and should be practised regularly. Kicking in long distance swimming uses a great deal of energy and its contribution to propulsion may not warrant that energy expenditure. When swimming in salt water, or in a wet suit that supports the legs, good alignment may be achieved with minimal reliance on kicking. 'Bursts' of vigorous kicking to assist 'wave riding' and clearing crowded and turbulent areas such as at starts and turning buoys may be required. Therefore some specific fitness needs to be developed for this.