...training specifically for conditioning without a well-developed strength base is a waste of time.
There's simply no better way to increase your work capacity than increasing your ability to produce force. If your primary interest is being more effective at moving yourself and/or submaximal or maximal loads more efficiently, training for strength contributes much more to your goal than training for endurance. *
100 kettlebell snatches in 5 min. 12kg-16kg.
Last time I performed it, I had used 16kg to 120 reps in 6 min. at a perceived effort level of 4+ [scale of 5]
Today after a light-medium pressing day I decided to test my "conditioning." Starting with 12kg for an easy warm-up 100 reps and after a short rest, began another set with 16kg. The blood blisters said to stop at 60. This in just at/over 8 min. I felt like I could've easily put in the second 100 were it not for my hands. Perceived level of effort, 3.
I haven't done the test in 3 months--definitely long enough to have "de-conditioned." While I wasn't conditioning, I've been making slow-but-steady strength gains for sure.
I'd like to test it later doing 16kg for 200 reps
If I were posed with the choice of working 2-3 times per week [strength] putting in an easy 50-80% effort and leaving feeling refreshed versus spend 1-4 times in HIT or tabata and its variants [gassed and tapped], I'd definitely go with the former--especially if I knew I'd only need 1-3 training days to "condition."
You do the math.