Factorial Structure of Individual Differences in Limb Speed, Reaction, and Strength

Abstract

Factor analyses were made of reaction time and maximal limb speed measurements of six movements, using a sample of 80 college men. Measurements of reaction time, speed, strength, and the ratio of limb strength to limb mass in four movements were also analyzed, using another sample of 70 college men. A factor labeled quickness of reaction was found to be characterized by relatively high loadings in reaction time items, although approximately one-fourth of the individual difference variance was specific to a particular limb and/or movement. A second factor labeled speed of limb movement was identified. It was characterized by low saturation; about two-thirds of the individual difference variance in speed was specific to a particular limb and/or movement. The factors for reaction and speed were uncorrelated. A third factor, limb strength in proportion to limb mass, had moderate saturation with about half of the variance in the specificity category. This factor was orthogonal to limb reaction and limb speed, and had a correlation of only. 52 with the factor simple limb strength. Limb and/or movement specificity accounted for 30 to 50 percent of individual difference variance in simple limb strength.