How Often to Strength Train
As mentioned previously, your really serious strength training should take place when you are not actively training for a triathlon. In the off-season, especially when the weather makes outdoor training difficult or impossible, strength training will help keep you occupied and maintain your fitness so that you don't start from ground zero when the new triathlon season arrives.
It's normal to want to do more than twenty or thirty minutes of strength training because you feel that you “didn't really do that much” for only a short period. The fact that you went through your workout without getting your heart rate way up can fool you into thinking you didn't do much. Have faith that the short strength workout did its job. Don't overdo it.
During triathlon season, you should limit your workouts to no more than twenty to thirty minutes, twice a week at most. It's okay to go to the gym for an hour or more, so long as a good part of that is socializing with your workout buddies and not passing the limit in pumping iron or whatever strength training you might have scheduled.
As the triathlon nears, cut back on your strength training. If you are on a twelve-week training schedule, cut your strength training in half in week eleven and skip it altogether in the week leading up to your race. Your strength workouts should follow your other triathlon training and should be the last or only workout of the day.
Strength training breaks down your muscles so that when they rebuild they come back stronger. In essence, your body is saying, “Hey, what we did today was hard. We need more strength to deal with this stress next time.” The bottom line is that your body then adapts so that it can meet the challenge next time. After a hard strength workout, this process takes about two days.
That means that if you do a strength workout before you go running, you haven't given your muscles time to recover, and your run will suffer as a result. The same applies, of course, to swims and rides. Further, there is a tendency after a poor training session to push it in the next one to make up. This can result in a spiral of bad workouts that results in burnout or, worse, serious injury.
