Using Lower Body Power to Predict Upper Body Bone Strength in Thalassemia Patients

Authors

Emily J. Van Horn, California State University, East BayFollow

Abstract

Thalassemia is a disease that reduces the body’s ability to produce hemoglobin. Thalassemia patients experience fatigue and avoid physical activity leading to low bone mass. Studies have reported that peak vertical jump power at take off calculated from a standing vertical jump (PPVJ) predicts tibial bone strength (TBS) including strain index (SSI) and cortical area (Ct.Ar.) (r=.69-.78) (Janz, 2015; Yingling, 2018 & 2020). Bone adaptation in response to mechanical loading is site specific. However, there is data that suggests peak power also predicts radial bone strength (RBS) (Yingling, 2021). Power has also been measured using a sit to stand power test (STSp), which may be more appropriate for clinical populations and older adults, but limited studies have used STSp to predict bone strength. PURPOSE: To determine whether STSp or PPVJ is more predictive of bone strength in the radius and tibia of individuals with thalassemia. METHODS: Young adults with thalassemia performed STSp using a linear transducer (GymAware) and a standing vertical jump using a Vertec. Peak power was calculated from body mass and linear velocity in the sit to stand (n=10), and from the Sayers equation using peak vertical jump height (n=15). Peripheral Quantitative Computed Tomography (pQCT) was used to determine bone strength as Moment of inertia (MoI), Ct.Ar., cortical bone mineral density (cBMD), and SSI in the 33% radius and 38% tibia sites. Muscle and bone relationships were assessed using linear regressions (Prism). RESULTS: STSp was found to significantly predict TBS (R2 (p value)): MoI (mm4)=0.76 (0.002), SSI (mm3)=0.74 (0.002), Ct.Ar.(mm2)=0.70 (0.01), cBMD (g/cm3)=0.20 (0.23) but did not significantly predict RBS (R2 p value)): MoI (mm4)=0.20 (0.19), SSI (mm3)=0.23 (0.16), Ct.Ar.(mm2)=0.01 (0.82), cBMD(g/cm3)=0.12 (0.33). VJPP significantly predicted both TBS (R2 (p value)): MoI (mm4)=0.47 (0.01), SSI (mm3)=0.47 (0.01), Ct.Ar. (mm2)=0.34 (0.03), cBMD (g/cm3)=0.12 (0.23) and RBS (R2 (p value)): MoI(mm4)=0.42 (0.01), SSI (mm3)=0.32 (0.03), Ct.Ar.(mm2)=0.18 (0.14), cBMD(g/cm3)=0.16 (0.14). CONCLUSION: Preliminary data suggests that PPVJ is a predictor of radial and tibial bone strength. Although the STSp was a stronger predictor for TBS, it did not predict RBS.

Recommended Citation

Van Horn, Emily J. (2025) "Using Lower Body Power to Predict Upper Body Bone Strength in Thalassemia Patients," International Journal of Exercise Science: Conference Proceedings: Vol. 14: Iss. 5, Article 54.
Available at: https://digitalcommons.wku.edu/ijesab/vol14/iss5/54