Reliability and relationships among handgrip strength, leg extensor strength and power, and balance in older men

Purpose: To quantify the reliability of isometric leg extension torque (LEMVC), rate of torque development (LERTD), isometric handgrip force (HG(MVC)) and RFD (HG(RFD)), isokinetic leg extension torque and power at 1.05 rad.s(-1) and 3.14 rad.s(-1); and explore relationships among strength, power, and balance in older men. Methods: Sixteen older men completed 3 isometric handgrips, 3 isometric leg extensions, and 3 isokinetic leg extensions at 1.05 rad.s(-1) and 3.14 rad.s(-1) during two visits. Intraclass correlation coefficients (ICCs), ICC confidence intervals (95% CI), coefficients of variation (CVs), and Pearson correlation coefficients were calculated. Results: LERTD demonstrated no reliability. The CVs for LERTD and HG(RFD) were <= 23.26%. HG(MVC) wasn't related to leg extension torque or power, or balance (r = 0.14-0.47; p > 0.05). However, moderate to strong relationships were found among isokinetic leg extension torque at 1.05 rad.s(-1) and 3.14 rad.s(-1), leg extension mean power at 1.05 rad.s(-1), and functional reach (r = 0.51-0.95; p = 0.05). Conclusions: LERTD and HG(RFD) weren't reliable and shouldn't be used as outcome variables in older men. Handgrip strength may not be an appropriate surrogate for lower body strength, power, or balance. Instead, perhaps handgrip strength should only be used to describe upper body strength or functionality, which may compliment isokinetic assessments of lower body strength, which were reliable and related to balance. (C) 2014 Elsevier Inc. All rights reserved.