This is a science-backed core routine that was used in an actual research study published in the Journal Sports Science and Medicine in 2019 (as seen in Day 1). The second day is a progression based off the first session and developed by JeFit. One of the Key Points from the Study: -Eight weeks of core-stability training two times per week improved dorsal trunk strength. Also in the study, three sets of each of the five exercises were performed. It was important that a neutral position of the spine during exercise was maintained. Participants were instructed to take a rest for one minute between each set. Our program suggests the same recovery between all sets. Stay Strong, MICHAEL WOOD, CSCS Jefit Team