Jesse Kropelnicki breaks down the mechanics of a speedy open-water swim stroke.
Swim mechanics is an area where athletes are subjected to a whole host of opinions—and determining which are valid can be tough. Thanks to underwater video analysis on hundreds of competitors, the great majority of them 50- to 85-minute IRONMAN swimmers, I’ve pinpointed the most common and critical items related to swim mechanics within triathlon.
When it comes to mechanics and form, swimming is the most difficult and critical to master of the three triathlon disciplines. While running, you typically have one foot in contact with the ground at all times, providing one less degree of freedom than swimming. Cycling allows constant contact with the saddle, both hands and both feet—accounting for five fewer degrees of freedom than swimming. Swimming, however, has infinitely many degrees of freedom because of a lack of sturdy connections to firm ground, which makes it even trickier to master its mechanics.
Pool Strokes vs. Open-Water Strokes Much of the confusion athletes feel with regards to swim mechanics is born from pool training, which focuses on a longer glide phase and lower stroke count. Open-water swimming in choppy waters requires a strong back end of the stroke, with a follow-through that pushes beyond the hips. Athletes who have a long glide phase in their stroke tend to be slowed by open-water chop while in this portion of the stroke, being re-propelled with each pull phase. Unfortunately, a long glide phase typically results in a slow turnover and, therefore, fewer pull phases per minute. This means fewer opportunities for forward motion. Because of this, open-water swims require a higher turnover than their pool-based counterparts.
For evidence, just watch collegiate pool swimmers. They see a major de-couple, relatively speaking, between their pool and open-water swim times. Although their graceful glide and strong front-end propulsion results in fast and efficient pool swimming, once offered to the unrelenting chop of the open water, these attributes are quickly minimized. This can be especially frustrating for those who race at the professional level and are used to crushing their competition in the pool.
Prioritize the Back-End Stroke
With mass starts and people all around, the front end is the first part of the swim stroke to get lost in the flurry. Bodies occupy the space where a long and gliding swim stroke might occur, so it becomes nearly impossible to get a strong catch and pull within the front quadrant of the stroke. This leaves the mid- to back-end of the stroke as the critical piece for maintaining any forward momentum. Since the back end of the stroke and follow-through are protected, no matter how crowded the swim is, it only makes sense to apply a strong focus of your attention here.
These two points explain why pool-born swimmers may have difficulty translating their grace and speed to the open water. It’s the front-end focused swimmers (who have a long glide, strong catch and low turnover/cadence) who are most efficient in calm, smooth, non-crowded waters. However, this same group is often outdone in the open water by the high turnover crowd with strong back ends to their stroke.
Originally from: http://www.ironman.com/triathlon-news/articles/2011/04/lava-magazine-promo-open-water-swim-mechanics.aspx#ixzz2VSE8ueRP