either pace or distance, there's an alarm to warn of fast or slow pace and an Autolap function. The RS200SD features five hear-rate zones, OwnIndex VO2 Max predictor and comfortable, soft Wearlink monitor strap. On the downside, it isn't as intuitive

-up to set a heart-rate target zone for that session and a fitness test which predicts your VO2 max. It also lets you record detailed heart-rate information for each rep you run, or every split in a race, providing you with your maximum and average heart rate

of useful features including a 200-lap memory, three target zones and detailed personal inputs such as VO2max and Body Mass Index (BMI). The chest strap chafes mildly but no more so than other HRMs. The regular functions such as the stop-watch and count

, where it can be converted into graphs, tables and even a training log.Allows you to program five separate key work-outs with specific HR zones.Predicts your maximum HR, VO2 max and counts calories burned.Contact: 01926 816166; www.polar-uk.comPolar M51

-of-the-range monitors available, packed with practical features. Among other things, the S610i lets you set and store heart rate zones for five different sessions; predicts your maximum heart rate and VO2max; counts calories burnt; records data every five seconds for up