Effects of biaxial pencil on writing biomechanics among children in kindergarten and early elementary school years

Children's writing posture has been a concern among parents and teachers [1, 2]. Poor writing posture often leads to arm, neck and back pain, scoliosis, kyphosis, fatigue, myopia, and other problems [2-4]. It also affects children's learning [5]. A two-factor repeated measures ANOVA (pencil × trial interval) was performed in this study.; comparing the effects of biaxial pencil and traditional pencil on writing posture and biomechanics. A total of 26 typically developed children participated in this study. The results revealed that, first, for the EMG data of upper extremity musculature, none of the muscles demonstrated statistical significance in pencils and intervals, except for extensor carpi radialis. Second, for the joint and postural angles measured via imaging, the significant differences were found on pencils in variables including shoulder horizontal inclination angle, head horizontal inclination angle, and trunk slant angle. Post-hoc analysis showed significant differences between the regular and biaxial pencils. No significant difference was found in trial intervals. Third, for participants' subjective soreness and pain, the reported soreness scales for all three pencils were mild, and no specific location of pain was reported. Most subjects felt that biaxial pencil was the most comfortable pencil to write with, followed by regular pencil, then regular pen-restricted grip height. Results of this study showed that using biaxial pencil can improve writing posture.