Get a Grip: Variation in Human Hand Grip Strength and Implications for Human Evolution

Ameline Bardo,Trudi Edginton,Tracy L Kivell,Georgina Donati,Cosmin Stamate,Haiko Ballieux,Gillian S Forrester,Katie Town

doi:10.3390/sym13071142

Abstract

Although hand grip strength is critical to the daily lives of humans and our arboreal great ape relatives, the human hand has changed in form and function throughout our evolution due to terrestrial bipedalism, tool use, and directional asymmetry (DA) such as handedness. Here we investigate how hand form and function interact in modern humans to gain an insight into our evolutionary past. We measured grip strength in a heterogeneous, cross-sectional sample of human participants (n = 662, 17 to 83 years old) to test the potential effects of age, sex, asymmetry (hand dominance and handedness), hand shape, occupation, and practice of sports and musical instruments that involve the hand(s). We found a significant effect of sex and hand dominance on grip strength, but not of handedness, while hand shape and age had a greater influence on female grip strength. Females were significantly weaker with age, but grip strength in females with large hands was less affected than those with long hands. Frequent engagement in hand sports significantly increased grip strength in the non-dominant hand in both sexes, while only males showed a significant effect of occupation, indicating different patterns of hand dominance asymmetries and hand function. These results improve our understanding of the link between form and function in both hands and offer an insight into the evolution of human laterality and dexterity.

Highlights

We searched for possible differences in the strength of hand dominance asymmetry across ages, and we found no significant interaction between age category and grip strength difference between dominant and nondominant hands for either males (F(9, 494) = 0.134, p > 0.05) or females (F(9, 772) = 0.207, p > 0.05) (Table S1)
We found a significant effect of hand dominance asymmetry, in which the dominant hand was significantly stronger than the non-dominant hand in both sexes, with an average difference being slightly higher for males (5.5%) than for females (4.2%) across all age categories
We found that adult human grip strength was influenced by a variety of factors, including age, sex, hand shape, and hand dominance asymmetry, consistent with previous studies

Summary

Introduction

The enhanced dexterity of the human hand is unique among living primates and is generally considered to have evolved through both (1) adaptation to bipedalism and a relaxation of locomotor selective pressures on the hands and (2) increasingly more complex tool production and use in hominins (i.e., group consisting of modern humans and our closely related extinct relatives) [1,2]. The manufacture and use of even relatively simple stone tools, such as Oldowan technology (2.6–1.7 million years ago) [5,6], would have required both increased cognitive function (e.g., learning, working memory/future thinking, planning and decision-making etc.) [7,8] and particular biomechanical demands on the anatomy of the hands [9,10,11]. It is likely that tool production and use played a critical role in shaping both cognitive development (e.g., with the crucial role of social learning) [12]

Objectives

Methods

Findings

Discussion

Conclusion