"When shadow boxing how hard should you shoot out the jab? Is that when you dial the intensity back or keep it the same with various step lengths and weight distribution?"
-Sean
Sean, you can hurt yourself shadow boxing if not careful. It is also the best tool for improving. The best boxers do more shadow rounds than bag rounds. Think about it, you usually miss, even when you are winning. Shadow boxing develops your form and poise better than anything, and should be combined with checking objects like walls and posts and door frames in between rounds.
Your shadow routine should mirror your boxing education.
Start out learning in slow motion, cultivating a relaxed state as soon as possible. This relaxed state is your learning and self assessment platform and also accounts for much of actual fight stamina in any combat art.
Build your tempo as you check your skills through feel, vision, your wife reminding you that your looking over your lead, etc.
Attain fight pace for the length of a fight being envisioned.
Warm down, slowing the motions to check them again against distortions in mechanics caused by fatigue.
So, if you are training for a three round fight your shadow routine should look like this:
1. One round in slow motion, using the skills that you have in your kit.
2. Another round in slow motion reviewing a single skill, applying it in an integrated fashion, or perhaps learning new skill, seeing where it fits.
3. A moderately paced round at half speed with plenty of movement.
4. One round just practicing defensive skills. Nobody does this. Be the guy that does.
5. Three rounds at fight tempo, on auto pilot, no thinking, just moving, defending and and hunting.
6. One review round, working on checking a skill that might not have felt right or did not seem to be there when you were working at top pace on autopilot.
7. One relaxed warm down round at half speed.
The best amateur I knew—more skilled than most pros—did 15 rounds of shadow boxing before each session, in a fashion similar to that outlined above, as a bio-mechanical self assessment and improvement clinic.
Be certain to penetrate with your foot work.
Also, be mindful not to lock out your joints.
Try bouncing your elbows off your body in your half speed rounds.
Pivots should be done at full exaggeration in slow motion, contracting to fight pace pivots in the full speed rounds. When, in your mind, you have the imaginary opponent in trouble in the fight tempo rounds, then use a full pivot for a finishing punch—and still remember to throw a clean-up punch at partial commitment instead of admiring your work.