Begin with a thorough warm-up, including dynamic stretching and mobility exercises for the legs, core, and upper body. For back squats, use a weight that allows for good form and a full range of motion. If 225/155 lbs is too heavy, reduce the weight to maintain proper technique and safety. In sit-ups, maintain a consistent pace and ensure full range of motion. If 40 sit-ups are too challenging, reduce the reps or modify with a different core exercise. For push-ups, aim for a full range of motion and maintain good form throughout the set. If 40 push-ups are too challenging, modify with knee push-ups or reduce the reps. This workout is a test of endurance and strength. Pace yourself across the rounds and exercises, and focus on maintaining good form and technique. Finish with a cooldown involving stretching, particularly focusing on the legs, chest, and shoulders.