The impact of hand dominance and ulnar and median nerve impairment on strength and basic daily activities

A possible anatomical and biomechanical explanation of the 10% rule used in the clinical assessment of prehensile hand movements and handed dominance

“…This may partly explain trends found in the literature (Provins and Cunliffe, 1972a,b) reporting that the grip strength test is likely to be unreliable when assessing lateralization. However it partially challenges the notion that grip or pinch strength is not or only weakly lateralized (Borod et al, 1984;Gutnik, 1990;Bohannon, 1997a,b;Hanten et al, 1999;Incel et al, 2002;Lee-Valkov et al, 2003;Yim et al, 2003;McDonnell et al, 2005;Rajan et al, 2005). Recent work by (Incel et al, 2002) supports the ''10%" rule, reporting that 10.93% of their right-handed subjects possessed equal or higher grip and pinch scores in the isometric strength grip and strength pinch tests from the left hand.…”

The impact of finger position on pinch strength

“…It has been found that hand strength and functional activities of daily living (ADLs) are directly correlated (Rajan, Premkumar, Rajkumar, & Richard, 2005). In this study, researchers found that "when hand strength increased, the ability to do the basic daily activities also increased" (p. 42).…”

“…The participant proceeded through the six pinch trials (bridge and groove for each of the three pinches), with 15-second breaks in between, in the order that was randomly selected. Pinch measurements were taken with the dominant hand only because research has found a correlation between ability to complete ADLs and pinch strength for the dominant hand only (Rajan et al, 2005). The rater encouraged the participant to squeeze as hard as possible during each trial by saying "go, go, go, stop", as the use of consistent instructions is important for standardization of the test protocol (Richards & Palmiter-Thomas, 1996).…”

“…As three-jaw-chuck strength increased, the ability to perform ADLs also increased. Rajan et al (2005) conducted a similar study with a sample consisting of 62 individuals with ulnar and median nerve impairment. Ulnar nerve impairment as well as combined ulnar and median nerve impairment reduced performance in ADLs by 45% and 60% respectively.…”

Impact of Finger Position on Pinch Strength?

“…Participants were given 15-second rest breaks between position changes, which was determined to be adequate by Trossman and Li (1989) [17]. Pinch measurements were taken with the dominant hand only because research has found a correlation between ability to complete activities of daily living and pinch strength for the dominant hand only [18]. The rater encouraged the participant to squeeze as hard as possible during each trial by saying "go, go, go, stop", as the use of consistent instructions is important for standardization of the test protocol [19].…”