AGE ADJUSTMENT: FACTORS IN ADULT SWIMMING by Pam Pitcher (Amersham SC) Note: Our thanks go to Pam Pitcher for this summary of the age adjustment formula used at the Amersham masters meet. She does not say so, but the overall results for each event, where the adjusted times for swimmers in all age groups are compared, are probably the main talking point of the day. It's great fun, but it is not clear where one goes with this information. Are the comparisons that we can make between performances by swimmers of different ages valid? Do they really mean anything, given the different training environments that have been experienced by different generations of swimmers? Does the adjusted time for an older swimmer mean that he or she was capable of that performance when younger, and conversely do the conversion tables give us an indication of the times we might be capable of or should be aiming at as we get older? There is considerable scope for development on the lines of the Amersham formula, and it is a pity that more interest has not been shown in it. As swimmers age up and performances in the older groups inevitably improve (recent masters history suggests that there is a long way to go before there is any stability in the record lists), there is clearly a need to keep the conversions up to date. To iron out the distortions resulting from some outstanding performances should ranking averages be used rather than records? Perhaps the tables could be developed to include a comparator between male and female performances or between events, and so on. AW __________________________________________________________ There has been interest for a number of years in the possibility of comparing swim times across the age groups of masters swimming. We are all too aware that as we get older there is a tendency for our times to get slower, however consistent our training programme msy be. But how do we know if we are actually improving as a swimmer or do we just blame those slightly slower times on creeping old age? Finnish compression factor A formula was devised in Finland in 1995 which converts swim times to a common baseline allowing adjusted results to be compared irrespective of age. The formula, or compression factor as it was called in Finland, was derived from the times done at the World Championships in Montreal in 1994 and Finnish masters records. Each swimmer's compression factor (CF) is calculated according to age and then used to adjust their swim times as follows: ________________________ / / {(98 - age) (98 + age)} CF = / ________________________ \ / \/ 95 Thus the swimmer's adjusted time is the time recorded multiplied by the CF. A swimmer aged 25 has a CF of 1, whereas a 50 year old has a CF of 0.887. Amersham age adjusted formula Amersham SC holds an open masters meet every February, and in 1997 we decided to introduce age-adjusted awards into the meet to provide an extra level of interest and as an experiment to see if masters swimmers would find age-adjusted times useful. In order to do this fairly and so as to have some degree of confidence in our results we chose not to use the Finnish compression factor, which is inaccurate when age adjusting older swimmers' times. In fact, any swimmer aged 98 takes zero time for any event! As we have entrants well into their 80's, they would clearly have an unreasonable advantage. In addition, the Finnish formula adjusts solely on age, whereas stroke and distance additionally have an effect upon perfomance. We therefore developed our own set of age adjusted formulae. These were based on the masters world records as at May 1994. World records are a measure of the times that can be achieved by serious, committed swimmers up to the age of 104. Thus we have a group of comparable people in terms of dedication and ability, the main difference between their times being the effects of aging. We then carried out regression analyses on both men and women on all strokes over all distances. As we suspected, the curves obtained, although similar in shape, showed significant differences between men and women, between short and long distances, and between the different strokes. For example, performance in the 200 fly falls away much faster with age than the 50 free. In all events, women's performances deteriorate faster with age than in the case of men. From each of these curves we derived a formula to process that specific event. Application at the Amersham meet For our own meet we used twelve different formulae, one for each individual event for men and women. (We swim 200 free, 100 individual medley, and 50's on all four strokes.) We calculate age to the day (date of meet minus date of birth equals age in days). With the age-adjusted results varying by only hundredths of seconds we feel we are being as fair as we can to swimmers of all ages. And since our masters meet computer software was written by ourselves and was continually being upgraded to ensure our meet would run as smoothly and efficiently as possible it was simple to include the age-adjustment calculations. After the 1999 meet we had three years' sets of age-adjusted times. Overall the results have made sense. The swimmers with the highest world and domestic ranking at the Amersham meet tend to be in the older age groups. So inevitably they outperform the younger swimmers when the times are age adjusted. On the whole our experiment has been well received and always provokes considerable interest. Amersham is not a small meet, but meets of this size and smaller might benefit from the inclusion of age-adjusted results, which would generate a new level of competition, especially amongst the older swimmers, who in some meets can 'swim over' to win their age group. We like to think our formula is a step ahead of the Finnish one. The Finnish factor is adequate for comparing one's own performances over time, but it is not suitable for age- related competitions as age must be calculated to the day and an appropriate formula based on stroke, distance, and sex for each event has to be applied. This ensures that no swimmer and no age group has an advantage. The Amersham formula is now several years old, and with the steady improvement in masters performances in all age groups it is now probably time for the application of new performance levels and further regression analysis. In fact, although we had thought of introducing "top man" and "top woman" awards in the meet in February 2000, other pressures prevented us from updating the formula. Even so, the unofficial results, published in this magazine, gave the swimmers a great deal of pleasure and amusement. W [Copyright (c) 2000 Watermarks]