``Limited Breathing Capacity'' Issue w.r.t. Flute Playing

In reply on the Flute Forum about a 13-year-old flute student being unable to play a 4/4 measure at 90 bpm with a comment from OP that it was due to limited breathing capacity:

Not a teacher but...

1. See if the limited breath capacity is physiological to begin with. This may be an undiagnosed medical condition like asthma, so tread carefully.

2. Focus on precision of tone production (i.e. embouchure problems). Chances are the person may be trading off using more volume of air to overcome an imprecise targetting of the air stream against the blowing edge (think shotgun versus sniper rifle towards aiming a target). To diagnose this, see if the person can play the wanted notes at a low dynamics (think piano or softer). If they cannot get a good tone from that, it might point to this problem. If they can, then get them to play for the required duration at that lowered dynamics, and slowly build up their embouchure control ability towards a more moderate dynamics.

3. Eliminating 1 and 2 as sources of the issue can mean improper breathing mechanics in general. Exercises that focus on moderate volume "air snatching" via the mouth and deep breathing diaphragmatic exercises (in through nose, out through mouth) should be done. Pay close attention to the shoulder movements when a breath is taken -- large shrugs indicate poor mechanics. Promotion of other aerobic exercises outside of flute playing may also be suggested.

Let's see if the true teachers have other useful suggestions to help.