Thursday, April 03, 2008
Session 52 - An Experiment to partake in!
So this morning we had a quality threshold swim session on the cards, however, I've also been meaning to test a theory about the relationship between stroke length and stroke rate and what this means for you related to your physical make-up, experience, race distance etc.
What ultimately determines how fast you move through the water comes down to 2 very simple variables - stroke length (meausred with the number of strokes taken per length, i.e. 50m) and stroke rate (how many complete strokes your arms complete in one minute, with left = 1, right = 2 etc.). For a detailed series of articlea on this interesting subject, go to http://www.swimsmooth.com/freearticles.htm#SR You will also find our SR / SL calculator at http://www.swimsmooth.com/strokeratecalc.htm quite useful.
Suffice to say, the theory which I have been "toying with" for a little while now (as discussed in the articles) is that selecting an appropriate SR / SL ratio for you to work at should not be a case of "one size fits all" but should be individually tailored based upon such factors as your height, arm-span, musculature etc. For example, I often see swimmers who may have read about how to increase their efficiency through increasing their stroke length and working to reduce the number of strokes they take per length down to "ridiculously" low values, become frustrated when they tend to reach a plateau in their swimming. Does pursuing the longest possible stroke make for the most efficient stroke for everyone? Arguably not. All too often a long stroke becomes a slow stroke (see the equation, swim speed = SL x SR) and as such things start to rapidly "drop off". This results from those incredibly long, slow strokes having "dead spots" manifest themselves through "over-gliding". I personally hate the word "glide" in swimming. For too many people this implies "glide, stop and do nothing for a moment" - this shouldn't be the case. Yes you should be smooth (its all in the name, right!), but you should aim for the most efficient and rhythmical stroke that you can possibly maintain. This doesn't always mean a long stroke for everyone!
So the theory is this - at the Australian Institute of Sport, one of the Talent ID factors they look for in potential swimmers is the ratio between the swimmer's arm-span and their height. In theory, your arm-span should approximately equate to the same length as your barefoot height. Some people have arms longer than this ("long arms"), some have shorter arms than this ("short arms") and some are exactly equal ("even"). Through conducting multiple "swim golf" swim sessions in the past (i.e. swim 50m, count your strokes, add this number to the number of seconds it takes to complete 50m and thats your score. Like in golf, try to reduce your score by either swimming faster, or swimming with a longer stroke - which way of swimming gives you the lowest score without feeling too "strained"), it has become apparent from listening to my swimmers, that some simply do not find that a longer, smoother stroke is either more efficient, smoother or faster for them. I started to notice that it was typically the shorter, more muscular, female swimmers in particular with a preference for open water distance swimming who would make these remarks. Interestingly, the taller males within the group with "long arms" would state the complete opposite, that short fast strokes (whilst maybe faster overall) felt scrappy and inefficient. So, if you have long arms, do your low scores in "swim golf" come from fewer strokes per lap than short fast efforts? Or, if you have short arms, do these stroke count sets drive you nuts and simply feel like you lack rhythm and timing from pursuing and overly long stroke?
We tested this on Tuesday with my adult stroke development group (n = 16) and then again this morning with my main squad (n = 25). Tuesday's squad perfectly confirmed from doing the same 8 x 50m swim golf set as above that those with short arms favoured an increase in stroke rate and actually felt both more rhythmical and were faster than when trying to lengthen things out, whereas those with longer arms loved the idea of being longer and smoother. Unfortunately I did not collect any data from this. Thursday's group showed some interesting results. Out of the 25 swimmers, 13 had long arms, 7 had short arms and 5 were "even". After doing the swim golf set, 5 of the 13 swimmers with long arms said they got their best results and felt most comfortable when swimming "long", 2 said they got their best results going "long" but that it felt "forced" and "unnatural", whereas 6 swimmers found there to be no discernible difference between swimming short and fast or long and smooth in their swim golf scores. What was interesting this time though was that of the 7 swimmers with short arms, noone commented that they got better results from swimming "short and fast" as my theory would suggest, but all 7 found that the longer, smoother strokes were simply too "forced" and "uncomfortable" and "lacked rhythm". Of the 5 swimmers with "even" arms, all found that "long and smooth" gave them their best results, but 2 found this method to be too "strained".
So, what can we conclude? Well, the theory is sound in principle but requires more testing to confirm. I think that what is really interesting is that there was a distinct difference between what those with long arms feel like in the water compared with those with short arms, even if the findings weren't totally conclusive. Such a distinct difference even from a relatively small cohort suggests room for further investigation. This is where we throw it over to you. Complete the set as per the instructions of the board. Do the arm measurement thing and see which works best for you. Then let us know!