This study examines the use of a novel 2-dimensional echocardiographic technique to measure left ventricular (LV) systolic torsion or twist in normal human hearts during maximal exercise. The effects of dynamic exercise on LV twist have not previously been determined. LV twist was measured in 25 healthy human control patients before and after maximal treadmill exercise. LV end-systolic volume decreased and LV ejection fraction increased in a predictable manner. Systolic twist increased by 8.4 +/- 2.8 degrees (86%). Twist is believed to store potential energy and to play an important role in generating diastolic suction. The increase in twist observed may play an important role in facilitating LV diastolic filling during maximal exercise.