Objectives
The purpose of this study was to develop an estimated model of physical fitness age (PFA) to standardize an individual’s fitness level using health-related physical fitness data from the representative population aged 40-64 years in Korea’s National Fitness 100.
Methods
Two models of PFA were developed based on sex using chronological age as a dependent variable and results of fitness test variables (body fat [BF], handgrip strength [HS], sit-up [SU], VO2max, and sit-and-reach [SR]) as independent variables from the modeling group (N= 37,130).
Results
Cross validity was conducted utilizing data of the cross-validation group (N= 37,284) to verify the developed equations. Obtained equations for adults aged 40-64 years were Y = –0.264993 (HG) –0.190067(BF) +0.105595(SR) –0.099818(SU) –0.632665(VO2max) +0.758409(CA–52.47) +93.096878 for males and Y = –0.184767(HG) –0.059027(BF) +0.181517(SR) –0.193897(SU) –0.529020(VO2max) +0.76957(CA–52.79) +75.715087 for females. Developed equations had the goodness of fit as R2=0.845 (SEE=2.8 yrs.) for males and R2=0.849 (SEE=2.7 yrs.) for females.
Conclusions
We have developed physical fitness age equations for adults utilizing fitness test data from the National fitness 100 in the Korean population. The developed equations were found to be proper for standardizing the physical fitness level of the Korean population in both sexes.

KEY WORDS: Healthy aging, Health-related physical fitness, Fitness assessment, National Fitness 100, Physical fitness age