Do you mean what specific lifts or how the workout should be organized?

If you mean the organization, I like to do all the lifts at a weight that gives a strong fatigue after 15 reps or so. Hitting muscle failure is good for putting on mass and getting a lot stronger, but it'll wreck your endurance workouts for the rest of the week. However, if you don't get fatigued, you might not be getting as much benefit from the time in the gym. Maybe 2 or 3 sets of 15 reps on each muscle group.

Train full body movements the two days you are in the gym. For endurance sports, you never want to train "muscle groups". In fact any sport, should never train muscle groups. You shouls always be training specific movements to help increase your performance in that sport.

Think of the sport of triathlon. You need strong hips, very stable and strong core (and that doesn't mean a ton of crunches), strong rotator cuff and scapula muscles, strong and durable legs, balance and proprioception, mobility and flexibility throughout the entire body and very strong feet.

So, to design a workout based on these attributes you need:
-single leg balance work
-hip abduction/adduction
-front plank/side plank/glute bridging variations
-core stabilization techniques
-rotator cuff pre-hab (external/internal rotation, T's, W's, U's)
-single leg squats
-body weight exercises like chin-ups and push-ups
-stability ball leg curls
-single leg anterior reaches
-foam roll and lots of active stretching before and after workouts

Your sets and reps will depend where you are at in your season. On the single leg exercises, you never want more than 8 repetitions as they are very intense exercises. If you are in the gym to assist your triathlon training, then the workout is very specific. If you are in the gym for general fitness and a fantastic physique, then the workout will be different.

I always like to give examples of what a workout should looke like, so here it is:

We will say it is in season:

Foam Roll
Dynamic warm-up/active stretching
Shoulder Pre-hab: stability ball T's, W's, U's - 2 x 8/exercise

Mini-band Lateral Walks: 1 set 8 yards back and forth

Single leg balance: 2 x 20 seconds/leg

Plank: 3 x 30 seconds
Glute Bridge: 3 x 25 seconds
Slow Strict Crunch: 3 x 10

Chin-ups: 2 x 8, pair with
Single Leg Squat: 2x6/leg

Push-up: 2 x 15, pair with
Stability Ball Leg Curls: 2 x 8

This will help maintain your strength and keep you injury free during the season.

Any other questions, just let me know!

I, or rather, someone much smarter than me.second fitnessman's ideas. In Run Training for Triathletes Ken Mierke supports that weight training for a triathlete absolutely has benefits. To sum up what I can remember from a chapter in a paragraph, he says keep the workouts short and intense, for 2 days a week no more than 45 minutes for each workout. Make all the exercises over a large range of motion. Use heavy weight (no more than 8 reps), no repeat sets. Make each rep slow, work from 4 seconds down and 4 seconds up to 8 seconds down, 8 up. When that is comfortable, move up in weight.

Yes could you explain some of those exercises in more detail?:D

Core Performance Endurance Book by Verstegan (or some spelling like that). Problem solved. Best thing out there IMHO.

Or do it on-line at coreperformance.com, which I do.

It is geared towards tri folks and it does a lot in a short amount of time. Mark's stuff is great - plans for all kinds of stuff. A HUGE number of pro athletes go to his place in AZ.