# Trend Forecasting in Swimming World Records and in the Age of World Record Holders
## 4 Discussion
While for short-distance events there was a trend of an increase in the age of world record holders over the decades, an unchanged trend was found for long-distance ones. The consistent trend of swimmers achieving world records at older ages in short-distance events may be attributed to the requirements of the effort. These events typicallyrely heavily on explosive speed and power, which can be maintained or even improved with age through targeted training and experience [28]. The continued development of race strategy details [29], along with the improvement in novel recovery approaches or medical support [30], help older swimmers to extend their competitive careers and continue setting records at older ages. In contrast, the variations observed in the age of world record holders in long-distance events may reflect the unique physiological demands of these races. Long-distance events require a combination of endurance, aerobic capacity, and race-pacing maintenance [31], which may peak at an earlier stage of an athlete's career. Younger athletes may have a natural advantage in terms of aerobic capacity and recovery ability, allowing them to excel in longer-distance events more easily than their older counterparts [32]. Forecasting models of WRs (Figures 1 and 2) show promising evolution over the next decade (during the 2020-2029 period). As an example, predicted WRs for the 100 m freestyle event are 46.79 s and 46.69 s within the next few years. Three male WRs have already been broken within this time frame (e.g., [PERSON] clocking 46.86 s in the 2022 European Aquatics Championships in Rome, [PERSON] clocking 46.80 s and 46.40 s in the 2024 World Aquatics Championships in Doha and in the Paris 2024 Olympics, respectively). This means that our models are fair and acceptable, and it should not be expected that swimming WRs will plateau so soon as previously reported by [PERSON] et al. [24]. There have already been 20 individual WRs (11 male and 9 female) in long-course events within this decade. Although there is a consensus that swimmers at this stage have already reached their physiological limits [33], there seems to be some room for improvement for further advancements in swimming performance. Considering the projections for the winning time in the Paris 2024 Olympics [34], it was not expected that any WR would be broken. Still, a fair number of WRs in freestyle events were achieved (two male WRs) and were somewhat in agreement with what our forecasts showed. Forecasting models related to the age of record holders (Figures 3 and 4) showed us a mixed path. General stabilization in the age of world record holders in most of the freestyle events should be expected in the upcoming years. Stabilization in the age of male and female elite freestyle swimmers was seen between 1994 and 2016. Contrarily, [PERSON] et al. [26] found an increase in the age of swimmers across World Championships and Olympic Games finals in a 20-year time frame (from 1992 to 2013). Although this might be a phenomenon with a random fluctuation, the age of a world record holder may sometimes not be within the age interval of those participating in the finals of great events. Some recent great performances were achieved by phenomenal teenage individuals like [PERSON] (15 years) and [PERSON] (17 years). At the time of breaking the WRs, those swimmers were far from the 2016 average age (~23 years) of freestyle world-class swimmers [35]. So, this seems to be a random phenomenon with a nuanced pattern that opens space for outlier emergence that may counteract some forecast results. The existence of outliers is a well-known phenomenon that should be embraced by those who regularly work on sports prediction statistics [36]. As such, any future observations in this case should be interpreted with caution. This study contributes valuable insights into the world records and age dynamics (e.g., career peak) for world-class swimmers. Coaches should be aware that there are sex-specific and event-specific dynamics in evolving trends over the decades.