MN118 Ānāpānasati. Mindfulness of Breathing. Discussion from Dhamma Wheel

MN118 Ānāpānasati. Mindfulness of Breathing. Discussion from Dhamma Wheel.
http://dhammawheel.com/viewtopic.php?f=25&t=1937

MikeNZ66

In each stage of the 16 stages in MN 118 (apart from the first two), the phrase is used: 'He trains himself (sikkhati)". What exactly does this refer to to? Does it refer to the three heightened trainings in sila, samadhi & panna listed in AN 3.88? If so, what of the translation: ‘Mindfulness of breathing’? If the mind is training itself in much more than merely watching breathing, may the term “of” be too limited or narrow in scope here? If so, is there any alternative renderings of ‘anapanasati’ that might indicate a bigger picture?