The book Body by Science by Doug McGuff and John Little presents a strength-training program based on the experience and research of a medical doctor and a leading fitness researcher. It’s main premise is that you can exercise effectively for only 12 minutes per week.
At first blush, this claim may seem to good to be true. However, the authors support their assertion with a fascinating (albeit somewhat challenging for the layman) medical explanation of what happens in the body metabolically during exercise. In a nutshell, a small number of specific, high resistance (not “cardio”) exercises (called “The Big Five”) performed very slowly will fatigue all the major muscle groups. It can take the body a week more to fully recover and repair the muscular micro-damage (which is how growth occurs). Hence, 12 minutes per week.
They describe a machine weight (using Nautilus equipment) and a free-weight version. I personally prefer a body weight only approach similar to the Scapula Shrug Circle (adding the full flexion/extension of the arms as well as squats or lunges).
The virtue of the “Big Five” workout is that it’s simple and accessible regardless of physical condition or age. If you are not comfortable with performing, or able to perform, the workout on your own, there are even professionals who provide equipment and coaching. (While not an endorsement, one such provider seems to be Superslow Zone.)
A major weakness of the “Big Five” workout is that it does not address joint mobility or movement compensation (in contrast with CST).
If exercising once a week for about 15 minutes is all you are able / willing to do, this is a reasonably effective approach. In fact, the “Big Five” exercises reflect part of a core principle of CST, namely, 6 degrees of movement. However, there is far greater benefit to receive from CST because CST provides a much more robust set of fitness “tools”.