Prediction of grip strength in Iranian young healthy population

Grip strength (GS) is an important measure of general health to predict mortality, disability and function of the hand. The purpose of this study was to develop equations to predict grip strength based on several anthropometric measurements using a multiple regression analysis. Four hundred and eleven males and 671 females college students, ages 18-30 years, in good health, participated voluntarily in this study. This sample was randomly assigned to the model-development (n=867) and cross-validation (n=215) groups. Four equations were developed by using data from the model development group, then cross-validated on the second group. A hand-held dynamometer was used to measure grip strengths. All anthropometric measurements such as hand anthropometry, forearm circumference (FC), lean body mass, skeletal muscle mass and arm muscle area were taken according to standard techniques. It was found that grip strength has a significant correlation with all anthropometric measurements. Forearm length (FL) was correlated to grip (68% explained variance) in a linear relationship, followed by upper limb length and SM. All four equations were confirmed by cross-validation. Because of simplicity and easy-to-measure the following equations were selected for prediction grip: Dominant hand, A) 0.464×Age(yr)+0.392×Height(cm)+0.681×BMI-13.035×Sex(0 for men and 1 for women)-46.160, B) 0.029×FC×FL-8.634×sex+13.872; Non-dominant hand: C) 0.347×Age+0.386× Height+0.657×BMI-13.313×Sex-44.243, D) 0.029×FC×FL-8.752×sex+13.788. The six easy-to-measure cofactors sex, age, height, BMI, forearm length and forearm circumference provide a highly accurate prediction of normative grip strength.