Distal upper extremity motion during keyboarding

Abnormal computer keyboard typing patterns have been associated with musculoskeletal disorders of the upper extremities. Threshold values for quantifying abnormal distal upper extremity function during typing have been established to identify typing behaviors that may place the computer user at risk for developing an injury. In this paper, the joint displacements of repeated typing tasks were normalized using previously collected opto-electronic motion capture data of the distal upper extremity during typing, histogram distributions of each movement showed the amount of time subjects were beyond threshold values and a Gaussian curve fit was observed to adequately describe angle distributions for a repeatedly typed sentence. Results indicate that normalized measurements of angle deviations during a typing task are highly repeatable and tend to follow a Gaussian distribution. Normalized data could be used to determine the efficacy of the current threshold values in quantifying the risk of injury to the upper extremity while typing, especially for applications within a rehabilitative setting.