Do high impact exercises produce higher tibial strains than running?
GROUND: Bone must have sufficient strength to withstand both instantaneous forces and lower repetitive forces. Repetitive loading, especially when bone strain and/or strain rates are high, can create microdamage and result in stress fracture AIM: To measure in vivo strains and strain rates in human tibia during high impact and moderate impact exercises. METHODS: Three strain gauged bone staples were mounted percutaneously in a rosette pattern in the mid diaphysis of the medial tibia in six normal subjects, and in vivo tibial strains were measured during running at 17 km/h and drop jumping from heights of 26, 39, and 52 cm. RESULTS: Complete data for all three drop jumps were obtained for four of the six subjects. No statistically significant differences were found in compression, tension, or shear strains with increasing drop jump height, but, at the 52 cm height, shear strain rate was reduced by one third (p = 0.03). No relation was found between peak compression strain and calculated
