When I first started triathlon, I lifted all the time. Then I started working at a gym 10-15 hours a day, and I had plenty of downtime between sessions to lift. I thought it was important, and that it would make me a better athlete (because I liked it and wanted to do it, not because of any empirical evidence, although there is some out there). As I've gotten older (and had better things to do) and done longer distances (necessitating more time swimming, biking, and running), I've prioritized strength training less and less and less . . . until it's become a little joke among my co-workers ("What?! Jamie is actually lifting?!") And after 8 years as a personal trainer, I'm less gung-ho about how valuable weight lifting is for endurance athletes. There's plenty of evidence that strength training makes better athletes, but there are just as many coaches and researchers who question those findings.
The question of whether or not to weight train comes up once or twice a year on the Slowtwitch discussion boards, hotly debated between the athletes who swear by weight training and those who think it's a horrible waste of time and makes you a stupid, gullible, Gatorade-guzzling tool (which is why I mostly stay away from Slowtwitch's forums).
This year I am leaving the world of triathlon for criteriums, road races, and (most importantly!) cyclocross. I've found a team that I like (more on that later), and have taken the "Swim" and "Run" columns out of my annual training plan. As a result, I have this weird free time thing, and I don't know what to do with myself. It feels strange only doing one workout in one sport every day . . . so I'm making a concerted effort to do more strength training this year. Since I'm such a generous person, I'm sharing my base phase strength routine here with you (actually, I just want other people to suffer as much as I have been). There's nothing magical about this routine. It addresses some of my personal weak areas, but mostly it's designed as a high-intensity workout to help me lose the 8 lbs. I've gained since September. There are shortcomings to this workout, too: it stays mostly in one plane of movement; it focuses on large, compound movements in the same muscle groups to the detriment of corrective exercise; it has traditional sit-ups (which have fallen far out of favor). But I like these exercises, and I'll actually do them. For me, that trumps the disadvantages. Maybe they work for you, too.
This isn't a great routine if you're new to strength training, or to working out in general. Find another program if that's you. There are high-risk movements in this routine: the sit-ups, the overhead lunges, the atomic push-ups, and the thrusters all have the potential to mess up your back if you don't know how to do them correctly. Consult a doctor before you start a new exercise regimen, and work with a trainer (or at the very least a knowledgable friend) if you don't know what you're doing. Disclaimers aside, I hope this routine helps you.
Circuit A (20 reps each for time)
Burpees over bar
Pull-ups (I can't do 20; do as many as you can)
1:30 rest, then repeat
Circuit B (15 reps each for time)
TRX face grabs
1:30 rest, then repeat
Circuit C (10 reps each for time)
TRX atomic push-ups
Kneeling forward lean
Side plank w/ knee/arm extension
:30 rest, then repeat