Non-physiological direction loading increases bone adaptive responses by enhancing lacunocanalicular fluid dynamics <-I believe that torsion and lateral loading(termed LSJL or Joint Loading Modality in scientific papers) are two potential ways to induce longitudinal bone growth post puberty) These are both methods of non-physiological loading which is typically limited to the axial direction. Most of the anecdotal evidence of increased limb length post puberty involves torsional loading like baseball pitching, tennis, etc. Lateral loading of bones does not really occur at all but there are scientific papers that support that it could potential induce longitudinal bone growth(see the papers by Hiroki Yokota and Ping Zhang).

“It’s been proposed that bone adaptation is “error-driven”, namely, bone is more sensitive to non-physiological loading (e.g., loading in a non-physiological direction). However, the effect of physiological vs. non-physiological loading on bone adaptation and its underlying mechanism are not fully understood. We hypothesized that loading in a non-physiological direction would increase osteogenesis via enhancing fluid flow within the lacunocanalicular network (LCN), independent of the strain magnitude. To test this hypothesis, we first examined the effects of physiological and non-physiological direction loading on bone formation responses with axial and transversal in vivo loading models of the mouse tibia, respectively, under a strain-matched condition. Next, an in silico whole bone-LCN multiscale model was developed to compute loading-induced strains and fluid shear stresses within the LCN. Lastly, regression analyses were performed to examine the spatial correlations between bone mechanoresponses and fluid shear stress (and strain). Results showed that the transversal loading led to an increased cortical bone response compared to the axial loading even though the strains were matched. The transversal loading-induced increase in bone response was associated with enhanced lacunocanalicular fluid flow rather than strain. Additionally, strong correlations existed between bone mechanoresponses and fluid shear stress whereas no correlation was detected between bone responses and strain. These results support our hypothesis and may explain why bone adaptation is more sensitive to loading in a non-physiological direction. The findings also highlight the key role of the fluid dynamic microenvironment within LCN in regulating bone mechanoadaptation.”

“compared to the axial loading, the transversal loading enhances bone adaptive responses by increasing the fluid shear stress surrounding the osteocytes within the LCN”

“Most of the long bones of the skeleton bear physiological axial loading during habitual activities such as walking and running. According to Wolff’s law, bones are well adapted to this form of physiological loading”<-this is why lateral and torsional loading is so beneficial.

“the transversal loading leads to an increased cortical bone response compared to the axial loading even though the strain is matched”<-cortical bone response in itself may not induce longitudinal bone growth but there are other cells in the bone that respond to fluid flow that could result in longitudinal bone growth.

“high strain magnitude paired with low fluid velocity does not trigger a bone response”<-this could be why very heavy axial loading does not induce longitudinal bone growth.

This paper although not directly studying longitudinal bone growth supports the usage of torsion and lateral loading to try to induce as these loading modalities are superior to inducing fluid flow than axial loading as they are non-physiological.