In this post I'd like to expand on the idea proper training for the trunk muscles AKA the "core". Researchers like Stuart McGill emphasize that the primary role of the trunk muscles is to stiffen the torso to prevent motion. This stiffening will transmit force from the lower body to the upper body more efficiently - obviously useful for both striking and grappling. Stiffening the torso will also reduce the stresses on the spine and therefore contribute to a healthy spine and back.
In addition to the trunk exercises that I've discussed before I'd like to add anti-motion exercises to the set of trunk exercises that should be done. And I'd reduce the role of conventional exercises like the weighted crunch.
Unlike McGill I am not convinced that exercises like the crunch need to be eliminated entirely. Firstly, I'll reiterate that I do not recommend a high volume of such training and instead focus on force production with a small volume of weighted exercises. Secondly, there are some limitations to the research that McGill has done which I have not seen addressed. Thirdly, I think McGill generalizes from the physical therapy to the sport training setting in ways that may not be valid.
Specifically, while a relatively sedentary office worker or cashier should focus on excellent posture and limiting spinal motion an athlete definitely needs to move their torso. Just look at the spinal motion, in three planes, of this pitcher. This is good pitching mechanics.
Overall a balance must be found in the program between these competing aspects of trunk training. And the balance will be different depending on the person. A new student may be hyper-mobile or have poor posture and so focusing on torso stiffening will benefit them most. Or they could be deconditioned such that the basic isometric exercises will be the most they can handle initially. But with a more advanced athlete the need will include more motion in the balance of exercises, as well as plyos and conditioning like the ropes or heavy bar.
Sample Exercises in the Anti-Motion category include:
Any of the planks and variants, though I will emphasize the value of adding weight or other difficulty to these exercises as building up endurance in these has diminishing returns.
Basic exercises also include the Pallof press and it's variation. An advanced version would be a Push-Pull exercise like this, except with the torso held motionless. Similarly, woodchoppers done with the torso still and reverse woodchoppers.
Anti-motion exercises can also include simpler core exercises like leg lowers, rollouts and deadbugs, when the emphasis is on keeping hips inline with the shoulders, spine neutral and hips stable.