The answer to this question depends on many variables:
-Fitness level of the participant
-Length of the triathlon event (sprint vs. ironman)
-Areas that need improvement (aerobic, anaerobic, swimming, running, biking, all of the above, etc.)
-Time left to the event
-Indoor or outdoor training (I prefer outdoors)
The strength training program for a triathlon event it varies depending to the individual, so without much information here it’s difficult to give you a better answer. Some general information will not be much help in answering this question.