Those videos look good for conditioning, I don't think they're the best for upper body resistance type training, though. My own experience may bias me a little. I get exercise-induced asthma. Because of this, I do well at the level of a fairly fast walk, but don't progress much with running etc. I also do okay lifting weights, since that's anaerobic exercise, the asthma thing isn't a problem. Sometimes when my breathing hasn't been so good, lifting weights will actually clear up my breathing.

I lift weights at home alone, that means some things I might do safely in a gym with a spotter would be dangerous. I make up for this with increased reps, if I were pinned under hundreds of pounds alone that would be dangerous, a hundred pounds is considerably less dangerous. One problem with this is that it puts me a little more into the aerobic vs. the anaerobic zone--so if I'm in allergy season or something, the limiting factor will sometimes be running out of breath instead of the sort of muscular failure I'm aiming at. I see a lot of combined leg/arm movements in these videos, squatting and over head pressing, that sort of thing. I think they have value for improving conditioning and agility/physical intelligence, but a handful of simple, compound movements is probably more efficient. Some sort of pulling movement, like a chinup or some kind of rows for biceps and back-- with a metal bar or even a two by four between two stable chairs, you could do horizontal pullups on your back, a horizontal pressing exercise like a pushup or benchpress for chest and triceps, and an overhead pressing exercise pretty much covers the upper body.

Weights don't have to be really heavy, there are studies showing a decent training effect even as low as 30 percent of 1 rep max, what really seems to matter is effort, doing enough reps to hit muscular failure--at 30 percent, that's likely to be around 30 sets or so. I see various dumbells/weights/kettle bells at Wal-Mart here at about a buck a pound, higher reps can get your foot in the door a little cheaper if that matters.