I do a bit of running for legs. It's mainly for swimming I want to do some upper body, I'm guessing bench presses and a few machines. I did get an induction but just looked at treadmills and rowing machines, cycling etc.
For swimming, there are some specific things you should thinking about like chin-ups.
Kinetically, look for closed chain upper body workouts.
You should not skip legs for a couple of reasons:
- running and cycling are highly repetitive, limited-ROM exercises with both concentric and eccentric loading cycles which leads to a number of problems if not addressed (ITB syndrome, knee pain, muscular adhesion points, etc.), which is why they need to be stressed through their whole ROM on a reasonably frequent basis
- most cardiophiles that I know get some pain in their ankles, shins, knees or back because of either the above reason, or because their bodies are kinetically unbalanced, i.e. One side is stronger than the other. This puts stress on bits of the body that don't like being stressed and - more specifically - shouldn't be stressed. Unilateral and bilateral (Google it) exercises are important to ensure the body is kinetically balanced, particularly with legs because of the forces involved, but also to ensure everything is working in the right way (i.e. the nervous system knows what to do with it all).
The trick is not to go nuts... Keep the reps between 3-5, don't train to exhaustion, and keep your rest intervals to above 2 minutes.