The Jefferson lift (or straddle deadlift) is a barbell lift that mimics picking up the famed 750-pound Dinnie Stones, a classic strongman test that was originally performed with big rocks.
If you want abs of granite and a powerful deadlift, add the Jefferson lift to your training. No other lift creates such enormous cross-body loads.
The Jefferson lift requires more individual personalization than most other lifts. Because of the awkward, asymmetrical position and inherent anti-rotation component, you need to find the right foot and hand position to get the best leverage. For most, it will be a variation on a squat position, with the upper torso facing forward.
Your first experience with heavy Jefferson lifting will be similar to that time you ate Taco Bell in a bus station, minus the explosive diarrhea. In other words, your deep abdominal muscles will feel like they took a beating from a boxer.