Albuterol aids resistance exercise in reducing unloading-induced ankle extensor strength losses.

While resistance exercise (REX) reduces ankle extensor (AE) mass and strength deficits during short-term unloading; additional treatments, concurrently administered with REX, are required to attenuate the greater losses seen with longer unloading periods. Subjects performed left leg REX, which otherwise refrained from ambulatory and weight-bearing activity for 40 days, while randomized to a capsule (placebo, albuterol) dosing regimen with no crossover to note whether albuterol helps REX mitigate unloading-induced AE losses. A third group of subjects served as unloaded controls.

Determining bone and total body mineral content from body density and bioelectrical response spectroscopy.

We hypothesized that one could assess total body mineral (TBM) and bone mineral content (BMC) from measurements of body density and bioelectrical response spectroscopy (BRS)-determined total body water by using a three-compartment (3C) model. We compared TBM and BMC computed from measurements of water (2H2O dilution or BRS) and body density (underwater weighing) with [4-compartment (4C)] and without (3C) mineral (dual X-ray absorptiometry) in 15 women and 16 men. BRS used multifrequency or single-frequency estimates of water.

Assessing total body and extracellular water from bioelectrical response spectroscopy.

We developed and validated assessments for total body water (TBW) and extracellular water (ECW) by using two resistance values of a new electric circuit model (CM) (two resistors; a capacitor and an inductor) with or without body mass. Fluid shifts occurring after 40 min of supine rest did not increase the validity of either estimate. CM estimates were valid; r = 0.

Determining blood and plasma volumes using bioelectrical response spectroscopy.

We hypothesized that an electric field (inductance) produced by charged blood components passing through the many branches of arteries and veins could assess total blood volume (TBV) or plasma volume (PV). Individual (N = 29) electrical circuits (inductors, two resistors, and a capacitor) were determined from bioelectrical response spectroscopy (BERS) using a Hewlett Packard 4284A Precision LCR Meter. Inductance, capacitance, and resistance from the circuits of 19 subjects modeled TBV (sum of PV and computed red cell volume) and PV (based on 125I-albumin).

Assessing total body protein, mineral, and bone mineral content from total body water and body density.

We hypothesized that investigators could assess bone mineral content (BMC), total body mineral (M), and protein (P) from body water (W) and density (DB) based on the theory of W. E. Siri (Advances in Biological and Medical Physics, 1956, p.