Alterations of hand muscle strength in children due to schoolbag carriage

BACKGROUND: Heavy schoolbag carriage induces pain and fatigue in children. It can alter the handgrip strength (HGS) in children – an important parameter given that most activities in school curriculum require hand dexterity. The purpose of this study is to explore if and how schoolbag carriage influence HGS in children. MATERIALS AND METHODS: Twenty-five healthy male participants (10–15 years) walked without schoolbag (0% load of bodyweight) or with schoolbags (weighing 4%, 8%, 12%, or 16% of their bodyweight) for 20 min on plane surface at preferred pace. The number of steps taken during walk was measured using pedometer. HGS was measured before and after each walk using dynamometer. The heart rate during walk was measured using Polar HR monitor. Pain occurrence in the entire body was mapped. RESULTS: HGS averaged for both hand decreased from 17.8 (±6.72) kg to 17.3 (±6.28) kg after 20-min walk (P = 0.033, paired sample t-test). The adopted speed and heart rate was higher when carrying a schoolbag but it portrayed no significant association with HGS. Occurrence of shoulder pain significantly associated with increasing in HGS of right hand after walking (Phi coefficient = 0.21[P = 0.030]). If shoulder pain was perceived during walk, there was a 2.5 times higher likelihood that the participants' HGS for right hand increased (odd's ratio = 2.515, 95% confidence interval = 1.086–5.825). CONCLUSION: Schoolbag carriage reduces HGS in children. Therefore, performing upper body conditioning exercises may help ameliorate the ill effects of heavy backpack carriage.