Here are some productive exercises I have used while boxing:
1)Russian Twists
2)Reverse Hypers or Back Extensions
3)Hang Cleans or Hang Snatches
4)Chins
5)Chest Dips
6)Upright Rows
7)Deadlifts(I always made these my core exercise because they hit so many muscles)
I'd do the twists and hypers on both of your training days.Focus mainly on back exercises like deadlifts,chins and cleans.Boxers focus alot on punching against a resistance like a heavy bag or mitts.To much emphasis on punching(which uses the pecs,delts and tris) while neglecting the pulling muscles(lats,traps,biceps) can result in muscle imbalances and injuries.This is why it is important to focus on back exercises during boxing training.Another mistake alot of boxers make is to include alot of long-distance running a.k.a. jogging.I agree that jogging builds up endurance(to a point), but, how often do you see a boxer "jog" in the ring?Instead of jogging, do wind sprints.Focus on short sprints(30 yards) and longer sprints(100 yards).My first boxing coach had us do a 5-6 mile jog every morning.All my energy was left on the road and during my matches, it showed.My next coach was all about sprints and my endurance skyrocketed.One other type of exercise you might want to try is sandbag exercises.They build functional strength and mental toughness.Try sandbag bearhug and carries with a bag that weighs atleast 50 pounds over your bodyweight.This will also build alot of strength for clinching.After working on the bearhugs for awhile, your opponent won't be able to pull you out of a clinch easily, if at all.And forget about hundreds of sit-ups and crunches.If you want to condition yourself to take gut punches, have a partner throw a medicine ball into your stomach or slam yourself in the midsection with a dumbell.Hope this helped out.
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