Toadstool I will grant the chest being a relatively worked muscle group in a pullup set however come on lets be honest here, the work you do on these other muscles besides the back/side shoulder and back on pullups is not going to be effective in any sense of the word in building muscle or gaining strength in these other groups of muscle.
I come at you as an enormous pullup fan. I work my back almost solely with pullups and chinups variations. I am doing sets of added 60 -80 pound pullups at the moment and just 3 days ago got a skinny 135 pound gym friend to hop on my back and did a few chinups for fun.
Trust me I know I used some abs and butt to stabilize myself with that much weight but beyond going that heavy will I really work my abs effectively enough to call it a "good substitute" for working these muscles? If not what's the point of even mentioning how they are working the muscles slightly? Are pullups really a good substitute for working the muscles pushups does? That is what mslookin4more was implying back on page 64 and it's just false. Surely you can not think that pullups are good for triceps chest and front delt come on man it's not like this isnt common knowledge in the fitness community!
Oh, I got the impression she was saying "do push ups until you drop some weight, then incorporate the pull ups." Pull ups at this point for The Don are not realistic. Pushups are! That's what I thought she was saying. I would agree with you in saying that one could be substituted for the other. They can't.
I could be wrong in saying that the pull up works the whole of the shoulder. I'm raising my hand over my head right now and the front of my shoulder and pec tense up. If I had a client, would I leave it at that? Certainly not. I'm just not confident in saying that the front part of the body is "negligible." I'd say it's pretty substantial. It teaches these other muscles to act as a stabilizer, tensing when their antagonists tense, and not in a way that impedes motion. I think that's very important.
would I remove other ab exercises in favour of pull ups and push ups? You know what - it depends on what you consider an "ab day." A lot of the people in the gym do like 20 different ab exercises in the same setting. I used to be that way myself. Now, I have a better understanding of how muscles work.
No, I wouldn't cut out every single ab exercise. I'd have a choice 1 or 2, possibly 3, depending on the client's skill, but I wouldn't dedicate a whole lot of time to "tackling the muscle from different angles." It's a waste of time.
Strength is gotten through high intensity. You can teach the abs to do it's job of stabilizing the spine through full range of motion in the movements like the pushup and the pull up. However, the tension built there is not increasing with each subsequent pull/push up day, so I would also throw in maybe an ab roller or leg raise or janda sit up, or dragon flies, to teach the abs to do the same job in high tension.
No i wouldn't substitute ab workout for the pull/push up, but yes I do believe absolutely they are worked effectively in these movements. If you're letting weights hang off your legs or your waist, then they work all the harder.
These are the reasons that I mention it at all.
As for the triceps, my answer will be the same. Look, if all you're doing is pull ups and never upping the intensity, then the work your arm can do will be limited. I'm here cranking out uneven pull ups and am training for the 1-armed pull up. The triceps HAVE to work. There is not enough stability in the smaller biceps for the eccentric contraction. The tricep works very hard on the more advanced progressions of the pull up. The basic pull up - I'm not so sure. I'd say it'd be limited. At DT's level of fitness, they'd be substantial. Again, would that be the ONLY thing I'd have his triceps doing? Of course not. Life is dynamic. His workout regime should be too. That being said, I'd toss out the tricep kickbacks ALTOGETHER
Just to give you an idea - I can't perform my average amount of reps if I do pull ups and push ups in the same day. My arms are exhausted. If the pull up was just the back muscles, and the push up was just the front muscles, that wouldn't happen at all. I have to time them separately.