Predictive equations for handgrip strength and quadriceps isometric strength

Abstract

Introduction: Grip strength or grip strength (FPM) is a method of evaluating the isometric grip strength using a method easy to perform, noninvasive and inexpensive. It has been used in the manual therapy patient evaluation, as well as a power indicator to the body as a whole and the functional performance of different groups of individuals. No study on the predictive models FPM, including young adults 50 years of age. Objective: To propose predicted equations for handgrip strength and quadriceps strength for the Brazilian population. Methods: This cross-sectional study, which evaluated 203 (105 women and 98 men) apparently healthy individuals aged 18 years or older. Body weight and height were measured and used to calculate body mass index (BMI = weight / height ratio, kg / m²). The volunteers also responded to the short version of the International Physical Activity Questionnaire
(IPAQ) to check the level of physical inactivity in accordance with their daily activities. The FPM review was done through hydraulic dynamometer in accordance with the recommendations of the American Society of Hand Therapists. Several predicted models were tested using subsets of demographic variables commonly used as predictors maximum FPM (FPMM). Continuous variables (age, in years, weight in kg, height in meters BMI and dichotomous (sex, male = 1) entered the model in a step by step method on with R2 value set as a criterion for entry / removing variables. Predicted values were calculated using the simplified model, using coefficients and rounded to three digits of accuracy. Statistical significance was set at P <0.05 for all analyzes. Results: The next to the dominant body (FPM-D), adjusted R2 values obtained using the step-by-step method began with 0.646 including sex (S) as the first variable. Entering the body weight variables (W) and height (H) significantly increased the adjusted values of R2 to 0.671 and 0.683, respectively; the inclusion of age (A) and classification IPAQ not increased significantly in the adjusted R2 value and therefore were excluded from the model (P> 0.100). Similar results were observed for the side of the body non-dominant (FPM-ND); adjusted R2 values obtained began with 0.620 including variable S as the first variable. Inserting the variable W significantly increased the adjusted values of R2 to 0.639; adding H, A or IPAQ classification is not significantly increased adjusted R2 value (P <0.100), but was kept in the model because the increased adjusted R2 value (0.640). Final prediction models for FPMP-D (adjusted R2 = 0.683, SE = 0.4 kgf bias) and FPMP-ND (R2 = 0.640, SE = 0.5 kgf bias) were FPMP-D = 20.108 × H × W + 0.083 + 13.265 × sexmale = 1 to 8.737; FPMP-NA = 9.23 + 0.086 × H × W × sexmale + 14.671 + 5.904 = 1. Conclusion: We conclude that simple attributes such as gender, age, height and weight can adequately predict the expected values of grip strength of the dominant upper limb and not dominant for Brazilian adults between 18 and 71 years.