ANALYSIS OF STROKE RATES IN FREESTYLE EVENTS AT 2000 OLYMPICS By David Pyne & Cassie Trewin Department of Physiology, Australian Institute of Sport The aim of this article is to examine the patterns of stroke rates of successful swimmers during the 2000 Sydney Olympic Games. Stroke rates of swimmers in the Final (top 8 swimmers) of selected Freestyle events were taken from the Competition Analysis of the 2000 Olympic Games (courtesy of the Biomechanics Department, Australian Institute of Sport). The stroke rates for each 25, 50 or 100m race split and placing in the 50, 100, 200 and 400 m freestyle events were collated. The interesting questions are … Were there differences in stroke rates between the sprint (50 and 100m) and middle-distance (200 and 400m) events? Were there any differences in stroke rates between the Men’s and Women’s events? How much variation in stroke rate was evident between swimmers in the same event? And how much difference was observed between first and last lap stroke rates compared to the average for the event for each individual swimmer. The individual and mean stroke rates for each of the finalists in the 50, 100, 200 and 400 Freestyle events are presented in Table 1. Statistical analysis (data not shown) indicated that there were no significant correlations between average stroke rate on any lap and final placing. The only exception was the Women’s 400m Freestyle where the placegetters had a significantly higher average stroke rate over the race than those swimmers finishing outside the medals. This indicates that there is considerable variation in stroke rate between different swimmers at the Olympic level. There is no clear pattern between placing and average stroke rate indicating that the hypothesis that the medal winners have a higher stroke rate cannot be supported. For example, Ian Thorpe (AUS) the winner of the Men’s 400m Freestyle had the lowest stroke rate of all the swimmers in the final, while Brooke Bennett (USA) the winner of the Women’s 400m Freestyle had the highest. Several observations can be made from the stroke rate data presented in Table 1. Firstly, the average stroke rates are higher for the shorter faster events (e.g. the 50m Freestyle) compared with the longer slower events (e.g. the 400m Freestyle). Indeed these data support the concept that there is a linear relationship between event distance and stroke rate … the shorter the event, the higher the stroke rate. A second observation is that the stroke rates are slightly higher for the female swimmers compared with the male swimmers across the range of events studied. This may reflect the larger physical stature of the male swimmers. The taller male swimmers will generally have a longer stroke length (distance per stroke) than their female counterparts. The female swimmers compensate for this anatomical difference by increasing the stroke rate. Another observation is the range of stroke rates evident in the Freestyle finals. The average difference in stroke rate (highest-lowest) in a given event from the 50m to 400m Freestyle was 17% ranging from 8 to 25%. Clearly, there is no single stroke rate that will suit all swimmers. Another way of presenting this data is in percentage form (see Table 2). These results again demonstrate that the shorter events are characterised by higher stroke rates. Using the mean stroke rate of the Men’s 400m Freestyle as the criterion stroke rate (for the purpose of this comparison only), the mean stroke rate for the 200m Freestyle is approximately 112% faster, with figures of 124% and 140% faster for the 100m and 50m Freestyle events respectively. The comparative figures were 100%, 110% and 129% for the Women’s 200, 100 and 50m Freestyle events respectively. These percentage figures may be biased by the higher stroke rate for the Women’s 400m Freestyle compared with the Men’s 400m Freestyle. Interestingly, the average stroke rate for the Women’s 200 and 400m Freestyle events was identical at 48 strokes/min. This could be interpreted as either a higher than expected stroke rate for the 400m event, or a lower than expected stroke rate for the 200m event, or both. In comparison to the Men’s stroke rates it would appear that the stroke rate for the Women’s 400m is markedly higher. This would suggest a different style of middle-distance swimming between the male and female swimmers, with the females adopting a more aggressive approach in terms of a faster stroke rate. The mean stroke rates per lap are shown in Table 3. For the 50m Freestyle events, each lap represents 25m, while in the 100 and 200m events the average stroke rate per 50m lap is shown. In the 400m events the average stroke rate per 100m is shown. It is common for the stroke rate to be higher in the first lap where swimmers are fresh and keen to establish the pattern for the race. The challenge for swimmers to take the race out fast – but not too fast – or fatigue may become a limiting factor in the last lap. In both the Men’s and Women’s 50m Freestyle there was a noticeable drop-off from the 1st to 2nd 25m split. The stroke rates were relatively even in the Men’s 100 Freestyle, although the Women’s 100 Freestyle showed a drop off similar to the 50 Freestyle. In the 200 events, the women had an even stroke right through the race (more like the 400 events) but the men showed a slight drop off in the 3rd and 4th laps. Although group trends are interesting, at the Olympic level it is important to analyse results for each individual swimmer. Table 4 shows the stroke rates for the Men’s 200 and 400 Freestyle Finals in Sydney. In the 200 Freestyle final, the winner Pieter van den Hoogenband (NED) a stroke rate of 46.3, with the Silver Medallist Ian Thorpe (AUS) has the lowest of all the finalists (41.8), yet the Bronze Medallist Massi Rosolino (ITA) has the highest at 51.0 strokes/min. Van den Hoogenband had the same stroke rate in the last 50m as he averaged for the entire race, where as the 4-8th placegetters all had lower stroke rates in the final 50m compared with their individual race average. Three swimmers showed a difference of more than 4 strokes/min from the 1st 50m (compared to the average stroke rate for the race) and these swimmers finished 4th, 5th and 8th. It appears that male swimmers take the 200m Freestyle out fast, and then try and hang on and minimise the decrease over the final 50m. Among the interesting observations in the 400m Freestyle final are: Ian Thorpe (AUS) the Gold Medallist again has the lowest stroke rate of all the finalists, but Massi Rosolino (ITA) has the second highest; The first 100m split has the highest average stroke rate (43.3 strokes/min) for any 100m split of the race; the 2nd and 3rd 100m splits have a lower average stroke rate, but the final 100m sees an increase as the swimmers fight for the finish; Grant Hackett had a 5.4 decrease in stroke rate from the first 100m to the second 100m (46.1 to 40.7) and one was one of only two swimmers (the other being Dragos Coman who finished 5th) whose stroke rate in the last 100m was slower than the average for the entire race. In contrast to the 200m final, it appeared that the 400m swimmers swam at a much more even stroke rate throughout the race. The stroke rates examined here were collected and analysed from filming of the Olympic Finals by the Biomechanics Department of the Australian Institute of Sport as part of its service to both the Australian Swimming Team and all the nations represented in Sydney. Of course, this extensive analysis is only available to National Team swimmers. Stroke rate can be measured simply with a stopwatch. Some models will have a stroke rate mode where the stroke rate will be instantly calculated and displayed by timing a series (usually three) complete stroke cycles. Some watches only require a single stroke cycle to be timed for conversion into stroke rate (number of complete stroke cycles per minute). Even a basic stopwatch (those with a special stroke rate mode) can be used to calculate stroke rate. To calculate stroke rate in this way, you need to record in seconds the time required to complete three full stroke cycles and divide 180 by this number. For example, if the time for three stroke cycles is 4.52 seconds, the stroke rate = 180 / 4.52 = 39.8 cycles/minute. The primary take-home message from this analysis is that coaches should determine the stroke rate for each individual swimmer over each event distance they swim. The average difference in stroke rate between the swimmers in a given event was 17% ranging from 8 to 25%. There was no apparent relationship between stroke rate and place in the sprint and middle-distance Freestyle events at the 2000 Olympic Games. Some swimmers will naturally have a higher stroke rate and others a lower stroke rate. What might be important is to minimise the drop-off in stroke rate in the last lap of the sprint events (50m, 100m and even the 200m Freestyle events) and maintain an even stroke rate throughout the 400m event. The data examined here represents only one race, and coaches should compare results for a given swimmer with their previous stroke rates taken in other high level competitions.