If you are looking for something to do after a full body lift / PT day, typically the only thing you have left is cardio and core.
Often, our training programs are split routines with upper body on Monday, Wednesday, Friday, and lower body days on the days in between (Tuesday, Thursday, Saturday or Sunday). But if you decide to mix in some full body movements like power cleans, snatches, kettlebell work from the ground to overhead, and other carries and crawls that require the entire body to be utilized in coordinated movements, you may want to take it easy on the following day. Either take a day off if needed (too sore), or just do a cardio day. If you need something more to do as running, biking, elliptical, rowing, swimming, or other aerobic activities are too boring for you, try adding in some core work throughout the cardio day.
Warmup with Core Run / Pyramid: Repeat 10 times Run 50m or 20 jumping jacks 20 situps or flutterkicks *20 neck exercises (updown)even sets (left/right) odd sets *lie on your back and lift your head up and down 20 times and left and right 20 times immediately after the situps or flutterkicks.
Run or bike 20 minutes – do 10 min easy / 10 min fast if you want a negative split type run or bike workout. Strive to run or bike faster of the second half of the run/bike.
If you select the bike and prefer more options, try intervals of the Tabata type (20 seconds fast / 10 seconds slow)
or try the Intensity Pyramid: Bike or Elliptical Intensity / Resistance Pyramid 1-20 level in 20 minutes: RULE: Each minute gets tougher than the previous minute by 1 level of resistance.
First minute – level 1 – keep at 80-100 rpms if a bike or 40-50 strides per minute on the elliptical. Second minute – level 2, third minute – level 3, keep moving with the clock every minute on the minute until you get to 20 minutes (level 20 is very challenging). If you fail to keep the rpms up to the recommended zone, repeat in the reverse back until where you started. Ruck 20-30 minutes
*replace run or ruck with mobility day if needed *non-impact, stretch and foam roller
Personally, when all else fails, I do a mobility day of the following: Repeat 5 times Bike, elliptical, row, or swim 5 min Stretch, foam roll, or massager 5 min
Swim portion of the cardio day (if available and time allows) Swim 500m warmup without fins Swim 30 min with fins – how far do you get? 1500m Or more?
Cardio days do not have to be just cardio, you can still work the core nicely as a warmup or mixed throughout the events. An idea is to stop running or biking every 5 minutes and do a few minutes of core work.
Do not forget the PT RESET and your favorite ab / lower back, and upper back/shoulder stretches and exercises as core day options.