Evaluating the correlation between grip strength, forearm circumference, motor dexterity and handedness in university students

Sammanfattning: Background: Handedness has been associated with different abilities, diseases and personality traits and its effect on language, motor dexterity and handedness are a well-studied matter. Measuring grip strength, forearm circumference and motor dexterity is a common way to get a better understanding the influence of handedness. Lately, studies have shown that there is a difference between right and left-handed in these above stated variables. Aim: The aim of this study was to investigate differences between grip strength and motor dexterity for dominant and non-dominant hand in both left and right-handed. A second aim was to investigate the association between grip strength and motor dexterity or forearm circumference. A third aim was to study the impact heredity have on handedness. Method: The study was designed as an experimental cross-sectional study, including 29 healthy students, age 18-30. Information about age, hand dominance, current health status, former elite carrier and heredity of handedness was collected. Forearm circumference were measured in cm at the largest part of the forearm. The Purdue pegboard test measured motor dexterity by adding pegs, collars and washers to the board on time, giving a total score. Takei Grip-D were used for grip strength (kg) measurement. Mann-Whitney U test, chi-square test and Spearman's correlation (rs) were used for analysis presented as median (min-max). Results: There was no significant difference between right (1.6kg; -4.1-8.0) and left-handed (0.6kg; - 3.4-7.6) regarding grip strength (p=0.43). Although, there was a large to nearly perfect correlation between forearm circumference and grip strength in both right (dominant rs=0.59; non-dominant rs=0.73) and left-handed (dominant rs=0.83; non-dominant rs=0.90). Also, a moderate correlation between motor dexterity and difference in grip strength was found for both right (rs=0.43) and left-handed (rs=-0.42). The studied group was not affected by their relative’s handedness to determine their own handedness (p=0.56). Conclusion: Forearm circumference and grip strength have a large association for both right and lefthanded. The correlation between motor dexterity and difference in grip strength were contrariwise comparing right and left-handed, indicating that handedness should be studied separate.