Advice for skinny guy

So the basics of gaining weight is to add calories.  Find out what your approx. BMR is and add a few hundred QUALITY calories.

For triathlons I advocate lifting for power.  3-5 sets of 3-5 reps.  You can look at schemes like Starting Strength, 5 x 5, or 5/3/1 and modify them to fit your schedule.  Personally I have squat day, deadlift day, and upper body day (usually revolves around power cleans and Standing OHP/Bench).  

Well power cleans are a total body exercise that recruits glutes, hams, quads, calves, back, and shoulders.  It's also a very explosive movement and IMO recruiting motor units to work in explosive/powerful contractions is needed for most triathletes.  You could switch out standing OHP for a number of things.  I like to have exercises in for shoulders.  OHPs hit the muscle group in a fairly comprehensive manner.

Why do triathletes need explosive work? I'm not trying to be a jerk here, I just don't really understand the specificity. 

With a squat deadlift and upperbody day how do you still S/B/R and recover?

I feel like cleans are sometimes a difficult exercise for people to learn without guidance and initial supervision.  Is there another compound move that you think accomplishes similar things without the same risk? 

I guess OHP would also not be my choice.  I question why anyone--unless their job requires it--needs to develop specific strength for pushing weight up over their head, and the risk of impingement with OHP is considerable. 

You're starting to sound like me

Too bad  I'll never touch you on the damn B/R!

So yeah, it's a bit of a balancing act at times.  I will give you that.  I find most athletes that train consistently can handle a couple hours a week of strength training on top of s/b/r'ing.

I'll qualify the power aspect by saying the athlete needs to have a decent base of fitness meaning that they have little in the way of muscle imbalances and have a good, functional strength base.  But power = speed.  Going fast is creating a ton of force and creating it quickly.  You can train the muscles and the neural pathways to do this by lifting heavy and explosively.  Lifting heavy will increase your Vo2.  It will increase your LT.  It will also, especially in conjuction with plyos, allow your body to transfer load better (running), and tolerate shorter ground contact times.  Speaking of shorter ground contact times research shows that as you get faster your contact times get shorter.  The key there is to be able to generate the maximum amount of force you can in that short, short period of time.  Lifting explosively helps train the motor units to do that.

Anyway if you're going to lift I'd suggest lifting for power.  You're already getting a lot of what is essentially high rep/low weight exercise through training s/b/r.  Now I'm not going to go over the top.  I sat through a lecture by Jay DiCharry at the USAT clinic where he advocated taking s/b/r volume out and replacing it with strength training.  He also had Lindsay Corbin hit PRs on deads, squats, etc the Monday before Kona.  I'd prefer to leave a short/intense lifting session in 3 days a week until you start seeing an impact on your recovery.  When you start to see that pull a session and reassess.  

This is really something that isn't going to be settled anytime soon.  I know I talked to 3 different prominent coaches in the last 3 months and each had a different idea of what triathletes should be doing strength training wise.

I'd like to hear more about that.  Is his talk available anywhere?

I don't think so.  He presented several of the subjects at the USAT coaching clinic in New Orleans including strength training.  Here's his website:

http://www.reporegon.com/