Yan, J. | Search bioRxiv

bioRxiv2026

Quantifying sprint force-velocity elasticity: implications for individualized training decisions

This study aimed to (1) develop an elasticity framework for the sprint force-velocity (F-V) relationship and (2) examine how maximal force (F_{0}), maximal velocity (v_{0}), and sprint distance modulate the four derived elasticity metrics, and (3) explore these elasticity metrics' interrelation. After modelling the F-V relationship differential equation, four elasticity metrics were defined as force elasticity (F_{e}), the elasticity of sprint time to F_{0}; velocity elasticity (v_{e}), the elasticity of sprint time to v_{0}; the force-velocity elasticity norm {(\mathrm{F}-\mathrm{V}}_{\mathrm{EN}}=\sqrt{F_{e}^{2}+v_{e}^{2}}), capturing the combined sprint time sensitivity to proportional changes in F_{0} and v_{0}; and the force-velocity elasticity ratio {(\mathrm{F}-\mathrm{V}}_{\mathrm{ER}}=F_{e}{\div v}_{e}), indicating which variable dominates the sprint time response. Model simulations showed that F_{e} decreased with rising F_{0} and increased with rising v_{0}, while v_{e} showed the opposite pattern. With increasing sprint distance, F_{e} decreased and v_{e} increased. Given its negligible effect on sprint time, ignoring air resistance yields a conservation law (2F_{e}+v_{e}\equiv 1), indicating that a gain in one elasticity metric necessarily diminishes the other in a fixed proportion. This framework also identifies a valley distance (d_{valley}) at {\mathrm{F}-\mathrm{V}}_{\mathrm{ER}}=2, where {\mathrm{F}-\mathrm{V}}_{\mathrm{EN}} is minimized (\sqrt{0.2}) and sprint time is least responsive to changes in F-V relationship variables. Empirical data confirmed that the two theoretical laws still hold approximately when air resistance is considered. By linking changes in F_{0} and v_{0} to sprint time across different distances, the elasticity framework provides a quantitative basis for estimating the theoretical sprint time response to documented changes in F-V relationship variables.

biophysics↗

bioRxiv2026

Differential expression of NEAT1 in the corneal endothelium increases susceptibility to oxidative stress in Fuchs Endothelial Corneal Dystrophy

Fuchs endothelial corneal dystrophy (FECD) is a disease of the corneal endothelium (CE) characterized by the loss of corneal endothelial cells (CECs) and guttae formation, ultimately resulting in corneal edema and vision loss. FECD primarily affects the central CE while sparing the peripheral CE, however the underlying mechanism contributing to the spatial differences remain unknown. Oxidative stress has been increasingly recognized as a key contributor to the pathogenesis of FECD, with CECs being particularly susceptible to damage from reactive oxygen species (ROS), high metabolic activity and ultraviolet induced DNA damage. The non-proliferative nature of CECs, along with the accumulation of oxidative damage can ultimately lead to CEC loss, a key feature of FECD. In this study, we induced oxidative stress with hydrogen peroxide (H2O2) on ex-vivo corneal specimens and observe increased cell death in the central region compared to the peripheral CE. To investigate these underlying differences, we performed bulk RNA sequencing (RNA-seq) on the central and peripheral regions of CE from FECD and normal cadaveric donors. Pathway analysis identified an enrichment of genes involved in collagen and extracellular matrix between the central and peripheral regions of CE in both normal and FECD, as well as between normal and FECD CE. Intriguingly, we identified the long non-coding RNA (lncRNA), NEAT1 as a top differentially expressed gene, with reduced expression in the central CE compared to the peripheral CE and lower expression in FECD compared with normal CE. Using corneal endothelial cell lines and ex-vivo specimens from FECD patients and normal cadavers, we found decreased NEAT1 expression levels in FECD and increased susceptibility to H2O2-induced oxidative stress. We observed that NEAT1 knockdown in normal and FECD cells exacerbated H2O2-mediated oxidative stress, and that NEAT1 overexpression protected FECD cells. We report in this study, a novel insight in the spatial differences in gene expression in the CE and identify reduced expression of NEAT1 in the central CE as a potential contributor to oxidative stress-related cell death in FECD. These findings provide novel insight into FECD pathogenesis and why FECD pathology preferentially affects the central CE. Antioxidants targeting NEAT1 signaling could be developed into novel therapeutics aimed at preventing FECD pathogenesis.

cell biology↗