This book has been approved by TWiEA - The World Isometric Exercise Association (www.TWiEA.com). The TRISO90(TM) Course is a 90-day/12-week advanced bodybuilding and strength-building exercise course based on the TRISOmetrics(TM) exercise system. The TRISOmetric(TM) exercise system consists of three proven science-based exercise principles which when combined form this highly advanced high-intensity exercise technique. The TRISO90(TM) Course is very advanced and not for the beginner. It is ideal for advanced trainers who want to take their workouts up to the next level. The TRISO90(TM) Course progressively increases in difficulty over the 90-day/12-week period, with routines changed every two weeks to keep your muscles constantly challenged and responding to growth throughout the 90 days. There are arrows clearly showing the direction in which the force/movement should be applied/performed. The TRISO90(TM) Course is a pure strength and muscle-building course making it ideal for the natural bodybuilder, or for anyone who wants to get into the best shape possible in the minimum amount of time. The TRISO90(TM) Course requires only a bare minimum of equipment to perform it, however, it can also be performed in any gym using readily available gym equipment. Recommended minimum equipment includes a screw-end adjustable doorway pull-up bar with foam handgrips, a pair of push-up handles, a length of thick (easy to grip) climbing rope, a strong padded footstool, a pair of Iso-Bows(R), a towel, a stable wooden block that is about 1.5 to 2 inches high (3.81 cm to 5.08 cm), 2 inches wide (5.08 cm) and long enough so that you can easily position your feet at shoulder-width apart if required. NOTE: The authors, Brian Sterling-Vete and Helen Renée Wuorio are exercise specialists who have worked closely with the NHS Innovation Team at the Greater Manchester Mental Health NHS Foundation Trust on two major isometric exercise trials during 2020. This was an outstanding success and they are now moving into a third much bigger trial before looking towards an expansion into more sectors of the NHS across the UK. TWiEA will be involved to conduct isometric exercise instructor training programmes for key NHS staff.