Strength training in the overall sense of strength and conditioning training helps all athletes maintain or improve coordination, muscle tone, body composition, maximal power, and muscular endurance. It is also anti-aging therapy you can get for free and can help prevent or mitigate injuries.
Strength training can help athletes keep their trunk and pelvis (core) in line in the final miles of a race, help them find a sprint to the finish, and help them eke out a few more watts on the bike leg of an Ironman. While triathlon training is mostly an aerobic discipline, including work on anaerobic ability (sprints and lactate threshold work) and strength & conditioning (weights, Pilates, Yoga, core work, plyometrics) help round out the program.
Generally speaking, 2 or 3 x a week doing light to moderate resistance 10-20 reps, 2 or 3 sets per exercise, 6-10 total exercises, is a safe place to start. Athletes with no or little prior experience should hire a trainer for at least a few sessions.
For beginners, find an easy weight and add just a little more to it. Advanced athletes will approach strength training just like they do their aerobic training; with a methodical seasonal plan. So the resistance and effort will vary depending on the time of the season.
An overall approach is to do 6-8 weeks of lighter resistance + higher reps but not to failure, 4-6 weeks of intermediate resistance + reps, 4-6 weeks of lower reps + higher resistance, then move into a maintenance program of medium resistance on the higher rep side. Everyone responds to strength training stimuli differently, so your mileage may vary. The above is a loose guide.
Basically, when a particular routine has become easy, athletes need to change it.
Some of the important exercises include:
Athletes should include several main exercises that involve most or all of the body (closed chain exercises). For example, a weighted squat with the bar requires the athlete to balance + engage the core while lifting, while a machine press eliminates the balance aspect. There are good reasons to use the press like rehab, back issues, etc; just be aware of the balance and core engagement aspect.
Marty Gaal, CSCS, is a USA Triathlon coach who lives in the Triangle area of North Carolina. Marty has been coaching endurance athletes since 2002. You can read more about OSB coaching services at www.osbmultisport.com.
One Step Beyond is the producer of the Powerstroke®: Speed through force and form freestyle technique DVD, intended to help new to intermediate triathlon swimmers become faster and more powerful in the water.