Percephtnl and hlotor Skills,2072, 1I4, 2, 514-518. @ Perceptual and Motor Skills 2012 ARE HAND-GRIPAND KNEE EXTENSION STRENGTH REFLECTryE OFA COMMON CONSTRUCT?I RICHARDW. BOHANNON Program in Physical nrcrapv, Deparhnent of Khesiologv Neag School of Educatiorr Uniaersitv of Connecti cu t Swnnmry.---{}ip and knee extension strength have each been used to charac- terize musdc strength. Whether grip and kncc cxtcnsion strcngth rcflect a common construct was investigated. Bilateral isometric grip and knee extension strength measures obtained by dynamornety were retrieved from the records of 34 adults who rvere at least 60 years of age (h4:ffi.2 yr'., SD:8.1) and had diverse non-focal diagnoses or problems. Relations betrveen neasurements lvere examined using Pearson correlations, Cronbach's alpha, and factor analysis. Pearson correlations (r:.55 to.89), Cronbach's alpha (.88) and factor analysis (loadings.85 to.91) all suggest that grip and knee extension strength reflect a common construct. Either grip or knee extension strength, therefore, may be adequate to characterize limb musde strength in older adr,rlts rvho are receiving physical therapy for diverse non- focal diagnoses or problems. Nevertheless, the measurement oI grip strength may be preferred because it is easier. Measurements of muscle strength are a key component of the phys- ical examination of patients receiving rehabilitation services (American Physical Therapy Association, 2001,). Although the strength of numerous muscle actions can be tested, it is quite common for the sake of parsimony that the strength of one or two muscle actions is used to characterize over- all strength. The actions used most often for this purpose in researcfu par- ticularly among the elderly, are hand-grip and knee extension (Geusens, van Devyveq, Vanhoof, Cassimary Boonery & Raus, 1,997; Samson, Meeu- wserL Crorve, Dessens, Duursma, & Verhaat 2000; Vissef, Pahot, Taafe, Goodpaste4 Simonsick, Newmary et n1.,2002; Landi, Russo, Cesari, Pahoq, Bernabei, & Onder, 2007; Bohannon, 2A09; Norman, Strobaus, Smolineq, Zoche4 Scheufele, Valentini, et aL, 2010; Xue, Beame{, Chaves, Guralnik, & Fried, 2070; Cawthon, Fox, Gandra, Delmonico, Chiou, Anthony, et nl., 2011). Some of this research provides insight into the correlation between grip and knee extension strength but nothing more (Samson, et a1.,2A00; Norman, et tr|.,201,0; Carvthon et a1.,2071). Consequently, the legitimacy of using either grip or knee extension strength to characterize limb muscle strength remains uncertain (Bohannon, 2008b). Before either grip or knee lAddress correspondence to Richard W. Bohannon, Departrnent of Kinesiology, Neag School of Education, University of Corurccficut, 358 Mansfield Road, Storrs, Cl 06269-21,01or e-mail (richard.bohannon@uconn.edu ). DOt 10.246tr / 03.26.PM5.174.2.51+518 ISSN 0031-5125