• Isoflavone exposure throughout suckling results in improved adult bone health in mice

      Dinsdale, E.C.; Kaludjerovic, J; Ward, W.E. (Cambridge University Press, 2012-02-15)
      Exposure to isoflavones (ISO), abundant in soy protein infant formula, for the first 5 days of life results in higher bone mineral density (BMD),greater trabecular connectivity and higher fracture load of lumbar vertebrae (LV) at adulthood. The effect of lengthening the duration of exposure to ISO on bone development has not been studied. This study determined if providing ISO for the first 21 days of life, which more closely mimics the duration that infants are fed soy protein formula, results in higher BMD, improved bone structure and greater strength in femurs and LV than a 5-day protocol. Female CD-1 mice were randomized to subcutaneous injections of ISO (7 Q1 mg kg/body weight/day) or corn oil from postnatal day 1 to 21. BMD, structure and strength were measured at the femur and LV at 4 months of age, representing young Q2 adulthood. At the LV, exposure to ISO resulted in higher (P,0.05) BMD, trabecular connectivity and fracture load compared with control (CON). Exposure to ISO also resulted in higher (P,0.05) whole femur BMD, higher (P,0.05) bone volume/total volume and Q3 lower (P,0.05) trabecular separation at the femur neck, as well as greater (P,0.05) fracture load at femur midpoint and femur neck compared with the CON group. Exposure to ISO throughout suckling has favorable effects on LV outcomes, and, unlike previous studies using 5-day exposure to ISO, femur outcomes are also improved. Duration of exposure should be considered when using the CD-1 mouse to model the effect of early life exposure of infants to ISO.
    • Predicting Lower Quarter Y-Balance Test Performance from Foot Characteristics

      Chimera, Nicole J.; Larson, Mallorie (Human Kinetics, 2020)
      The lower quarter Y-Balance Test (YBT-LQ) is associated with injury risk; however, ankle range of motion impacts YBT-LQ. Arch height and foot sensation impact static balance, but these characteristics have not yet been evaluated relative to YBT-LQ. Determine if arch height index (AHI), forefoot sensation (SEN), and ankle dorsiflexion predict YBT-LQ composite score (CS). Descriptive cohort. Athletic training laboratory. Twenty general population (14 females and 6 males; mean [SD]: age 35 [18] y, weight 70.02 [16.76] kg, height 1.68 [0.12] m) participated in this study. AHI measurement system assessed arch height in 10% (AHI10) and 90% (AHI90) weight-bearing. Two-point discrim-a-gon discs assessed sensation (SEN) at the plantar great toe, third and fifth metatarsal heads. Biplane goniometer and weight-bearing lunge tests were used to measure static and weight-bearing dorsiflexion, respectively. The YBT-LQ assessed dynamic single-leg balance. For right-limb dynamic single-leg balance, AHI90 and SEN were included in the final sequential prediction equation; however, neither model significantly (P = .052 and .074) predicted variance in YBT-LQ CS. For left-limb dynamic single-leg balance, both SEN and weight-bearing lunge test were included in the final sequential prediction equation. The regression model (SEN and weight-bearing lunge test) significantly (P = .047) predicted 22% of the variance in YBT-LQ CS. This study demonstrates that foot characteristics may play a role in YBT-LQ CS. The authors did not assess limb dominance in this study; therefore, the authors are unable to determine which limb would be the stance versus kicking limb. However, altered SEN and weight-bearing dorsiflexion appear to be contributing factors to YBT-LQ CS.