My background is/was (former competitor and consultant) in strength. When I am too lazy to discuss the topic (which is almost always these days) I typically just point friends and associates to Stronglifts 5x5. It is not what I go by as my personal plan is more specific to my goals, but it is a good starting place and not too bad to just cruise through their website.
Just be warned that true strength training can potentially mess up an endurance athlete's competitive season. I train endurance and strength each week as a non-competitor, but it is a very challenging task to manage training loads and recovery times. Dare I say almost impossible to be progressive in both. In fact I am not even sure how a triathlete can manage SBR in the week and also throw in strength training, but good luck.
https://stronglifts.com/5x5/