Hydrostatic - Under Water - Weighing w/ Isadora Williams - Olympic Figure Skater

This video shows Dr. Evan Matthews explaining how to estimate body fat percentage using a hydrostatic weighing (aka under water weighing) setup. For many decades this was the gold standard of body fat assessments, and today it is still a highly trusted technique. Isadora Williams, a member of the 2014 Winter Olympics figure skating team for Brazil, and Olympic hopeful for 2018, served as the participant in this demonstration.


Residual Volume Estimate Equations

Male: Residual Volume (mL) = 0.24 * Forced Vital Capacity (mL)
Female: Residual Volume (mL) = 0.28 * Forced Vital Capacity (mL)


Water Specific Gravity (Density) Equation

Water Density (g/cm3) = (1-((Water Temp Celsius + 288.9414) / (508929 * (Water Temp Celsius + 68.12963))) * (Water Temp Celsius - 3.9863) * (Water Temp Celsius - 3.9863))

Or look it up in a table (link below)
https://www.thermexcel.com/english/ta...


Hydrostatic Weighing Body Density Equation

Body Density (g/cm3) = BWdry  (((BWdry – BWuw)  Dw) - (RV + 100 mL))

where:
BW dry = body weight in air (dry) in grams (1 kg = 1000 g)
BWuw = body weight under water in grams (1 kg = 1000 g)
Dw = water density at a given water temperature in g/cm3
RV = residual volume in mL


Siri Body Fat Percentage Equation

Total Body Fat (%) = (495 / Body Density) – 450


Link to video on assessing body weight using a physician scale
   • Physician Scale - Body Weight  

Link to video on using a windmill type spirometer
   • Windmill Type Spirometer  

Link to video on body fat percentage using bioelectrical impedance analysis (BIA)
   • Body Fat Percentage - Bioelectrical Impeda...  

Link to video on how to perform skinfold measurements to assess body fat percentage
   • Skinfold Body Fat Assessment  



Link to watch Isadora Williams skate
   • Видео  



Link to Dr. Evan Matthews website.
https://sites.google.com/site/evanmat...