How does your swim time translate across pool formats?

World Aquatics conversion factors are derived from statistical analysis of large numbers of competitive swimmers who have raced the same event in multiple pool formats. They represent population averages and are accurate to within 1-2% for most swimmers. A swimmer with an exceptionally strong underwater kick will have a bigger advantage in short course pools, meaning their SCM or SCY times may be disproportionately fast relative to their LCM times.

The Olympic Games exclusively use long course metres (LCM) format: 50-metre pools. In the United States, high school and NCAA (college) competition use short course yards (SCY), with 25-yard pools. This means American age-group and collegiate swimmers primarily train and race in SCY, then must convert to LCM for international competition and Olympic Trials. Australia, the UK, and most of continental Europe primarily use LCM for major competitions.

Short course pools (25m or 25yd) produce faster times than long course (50m) because swimmers complete more turns per race. Each turn involves a push-off from the wall and an underwater phase where the swimmer travels faster than surface speed due to reduced drag. Elite swimmers can travel 10-15 metres underwater off each wall. Additionally, the deceleration between walls is reset more frequently in short course. The typical SCM-to-LCM conversion adds 1-2% to the time, while SCY-to-LCM adds 6-10%. Source: World Aquatics conversion methodology.

VO2 max varies significantly by age and sex. For men aged 20-29, the population average is approximately 43-46 ml/kg/min, with excellent defined as 51+ by ACSM standards. For women of the same age, the average is 36-38 ml/kg/min with excellent at 44+. VO2 max declines at roughly 1% per year after age 30, so a 50-year-old with 37 ml/kg/min is at the same relative fitness level as a 30-year-old at 43. Regular aerobic exercise can improve VO2 max by 15-20% in previously sedentary individuals. Source: ACSM Guidelines for Exercise Testing, Shvartz and Reibold 1990.

SWOLF (swim + golf) is a swimming efficiency metric calculated as time in seconds for one pool length plus the number of strokes taken for that length. For example, if you swim 25 metres in 30 seconds taking 20 strokes, your SWOLF score is 50. Lower SWOLF indicates greater efficiency. A typical recreational swimmer has a SWOLF of 55-75 per 25m, while competitive swimmers score 30-45. SWOLF is useful for tracking improvement because it balances speed and technique. Most swim-capable GPS watches calculate it automatically for each length. Source: Garmin swim metrics documentation, SwimSmooth coaching methodology.

World Aquatics conversion factors are derived from statistical analysis of large numbers of competitive swimmers who have raced the same event in multiple pool formats. They represent population averages and are accurate to within 1-2% for most swimmers. However, a swimmer with an exceptionally strong underwater kick will have a bigger advantage in short course pools, meaning their SCM or SCY times may be disproportionately fast relative to their LCM times. For recruiting purposes, coaches look at both converted times and raw LCM times to assess potential. Source: World Aquatics, USA Swimming recruiting guidelines.

The Olympic Games exclusively use long course metres (LCM) format: 50-metre pools. World records set at the Olympics are LCM records. The World Short Course Championships use 25-metre pools, and short course world records are tracked separately. In the United States, high school and NCAA competition use short course yards (SCY), meaning American swimmers primarily train in SCY then must convert to LCM for international competition and Olympic Trials. Australia, the UK, and most of continental Europe primarily use LCM for major competitions. Source: World Aquatics competition rules, USA Swimming.

Swimming is an effective stimulus for VO2 max improvement. During maximal swimming, VO2 max is typically 10-15% lower than during maximal running because the horizontal position reduces venous return. However, trained swimmers can achieve strong aerobic benefits through swim-specific training. Cross-training studies show that swimmers who add running see VO2 max improvements beyond what swimming alone provides. For overall cardiovascular health, swimming at moderate to vigorous intensity for 150+ minutes per week meets all major health guidelines and produces comparable reductions in cardiovascular disease risk. Source: McArdle et al., Exercise Physiology; ACSM position stand.