Effectiveness of various isometric exercises at improving bone strength in cortical regions prone to distal tibial stress fractures

Abstract

A computational model was used to compare the local bone strengthening effectiveness of various isometric exercises that may reduce the likelihood of distal tibial stress fractures. The developed model predicts local endosteal and periosteal cortical accretion and resorption based on relative local and global measures of the tibial stress state and its surface variation. Using a multisegment 3-dimensional leg model, tibia shape adaptations due to 33 combinations of hip, knee, and ankle joint angles and the direction of a single or sequential series of generated isometric resultant forces were predicted. The maximum stress at a common fracture-prone region in each optimized geometry was compared under likely stress fracture-inducing midstance jogging conditions. No direct correlations were found between stress reductions over an initially uniform circular hollow cylindrical geometry under these critical design conditions and the exercise-based sets of active muscles, joint angles, or individual muscle force and local stress magnitudes. Additionally, typically favorable increases in cross-sectional geometric measures did not guarantee stress decreases at these locations. Instead, tibial stress distributions under the exercise conditions best predicted strengthening ability. Exercises producing larger anterior distal stresses created optimized tibia shapes that better resisted the high midstance jogging bending stresses. Bent leg configurations generating anteriorly directed or inferiorly directed resultant forces created favorable adaptations. None of the studied loads produced by a straight leg was significantly advantageous. These predictions and the insight gained can provide preliminary guidance in the screening and development of targeted bone strengthening techniques for those susceptible to distal tibial stress fractures.

Conductive Scaffolds for Bone Tissue Engineering: Current State and Future Outlook

“…In addition to overcoming cellular attachment limitations, current approaches have needed new ways to further improve bone tissue ingrowth. Electrical and mechanical stimulation have been used within experimental settings in vitro, as well as with therapeutic rehabilitation in vivo for improved outcomes involving bone regeneration with positive results [ 176 , 177 , 178 , 179 ]. It has been shown that electrical conductivity within the 3D matrix of scaffolds promotes better tissue response when compared to induced stimulation through different mediums [ 180 ].…”

In vitro compressive properties of skeletal muscles and inverse finite element analysis: Comparison of human versus animals

“…Finite element (FE) Human body models (HBMs) are widely used for biomechanical analysis in biomedical engineering, transport safety, sport science, and other human involved activities (Florio, 2018;Halloran, et al, 2010;Hedenstierna, et al, 2008;Lenhart, et al, 2015). Skeletal muscle accounts for about 40% of the body mass, therefore an understanding of its mechanical properties is important for virtual human body modeling and related biomechanical application (Chomentowski et al,2011, Takaza, et al, 2013.…”