A 70 year old stunt man, Henri LaMothe, dives prone into 33 cm (13 in) of water from a height of 10.5 m (34.5 ft) in public performances. He has performed this dive almost monthly since 1948 without significant injury. In an effort to study his ability to avoid injury, especially in the thoracic region, the mechanical impact response of his sternum, abdomen, dorsal spine, and head was recorded in a series of low level [1.5 to 4.6 m (5 to 15 ft)] dives;​ and his musculoskeletal system was examined in detail.

Peak accelerations in the 4.6 m (15 ft) instrumented dives averaged 171 g on the sternum, 224 g on the abdomen, 25 g on the spine, and 15 g on the head. Kinematic analysis of the photographic data revealed that the unusual thoracic and abdominal tolerance, necessary to withstand such high levels of prone water impact, is obtained by precise body shaping before the water entry and subsequent effective deceleration through rapid and progressive displacement of a large water mass. The body control allowing contact with the water surface without injury is achieved by an excellent coordination of the diaphragm, extensor musculature, spine, and flexor musculature of the hips and shoulders during the dive. An estimate of the stunt man's impact response for the full-height public performance dive of 10.5 m (34.5 ft) having an impact velocity of approximately 14.4 m/s (46.9 ft/s) gives peak accelerations of 380 g on the sternum, 498 g on the abdomen, 68 g on the spine, and 41 g on the head. These predictions indicate that human tolerance to mechanical thoracic impact can exceed the commonly accepted injurious level of 60 g, when the impact is expected and enough time is available for well-coordinated tensing of muscles and shaping of the body.

Medical examination revealed unusual flexibility of LaMothe's spine and strong and wellcoordinated muscles in the abdominal wall. Surprisingly advanced arthritic changes, found on his dorsolumbar spine, shoulders, and left wrist, did not constitute any restriction of his performance.