This is an interesting split routine because the program design is based off a 2015 published paper in the International Journal of Sport Nutrition and Exercise Metabolism. This study showed a 4-day split was as good as a 6-day split in terms of training frequency. Results also demonstrated, building lean muscle mass was just as effective working out with less days (4 versus 6-days). This strength workout includes basically the same exact exercises found in the research. All subjects made great gains in only 4-weeks of training. The length of time was actually considered a study limitation, though, so try following this plan 4-days a week for the next 8-weeks for even better results. The study used 1-2 minutes rest between sets and 2-3 minutes between exercises. On the nutrition side - all test subjects were required to consumed 150 grams of protein each day. Baseline & Follow-up Strength Test The study tested for baseline and follow-up strength. Maximal dynamic strength was evaluated using the 1-RM test assessed on a free-weight bench press. The exercise test was preceded by a warm-up set (6–10 repetitions), with approximately 50% of the estimated load to be used as the first attempt for each test. The regular testing procedure was initiated 2 min after warm-up. Stay Strong with Jeft - MICHAEL WOOD CSCS