Individual sport training
Pros: Most gyms now have spin classes, and some offer running groups and Masters swim programs. These sport-specific training groups can be a good resource for integrating group sessions into an individual training program. This can be a great way to get started with some general fitness before turning to a more structured training program or else to focus on one sport intensively, usually during the off-season.
These group workouts are very effective and time-efficient, and can be a fun social activity as they allow a wide range of athletes to all train together.
A sport-specific training group or single-sport coaching situation (e.g. a track club or one-on-one swim technique session) can allow you to focus on improving a weaker area and provide a higher level of knowledge and insight into one of the individual sports.
Cons: The hazard of participating in these training groups year-round is that the program will be structured for single-sport athletes and generally does not provide for integration of all three sports. Runners may be able to perform three high-quality track workouts per week because they are focused on recovery, not swimming and biking, on the other days. Sport-specific training puts the onus on the athlete to plan and balance his or her own training program, but can be an effective tool in more experienced hands.
Olympian Samantha McGlone (@samanthamcglone) is a former 70.3 world champion and was runner-up at the 2007 Ironman World Championship. She lives, trains and attends medical school in Tucson, Ariz.