Global Journal of Medical Research, K: Interdisciplinary, Volume 22 Issue 4

1. Physical Activity Intensity and Fatigue Physical activity is beneficial to a certain extent but excess causes fatigue, which is detrimental. Fatigue can be considered as a marker for physical activity 5 . A study conducted by Torbjörnet. al in 2002 on 58115 participants show that there is an increase in degree of fatigue as the workload increased 13 . Another 2005 study by Jarrod D Presland et al., validated the finding of the previous study observing considerable central fatigue after prolonged physical activity 14 . A relatively recent study in 2017 by Smith et al., reported strong positive correlation between workload and fatigue in railway workers 15 . When it comes to the workload of schoolbag carriage, a study reported carrying 12% load of bodyweight to be moderate intensity while carrying 16% load of bodyweight to be a high intensity physical activity 4 . So, with increase in bag weight, the resultant fatigue might increase. Heavy backpack carriage among children is reportedly common which is seen in most of the literature associated with physiological effects of school bag carriage. a. Fatigue in load bearing muscles Heavy backpacks entails the use of load bearing muscles activated during any kind of physical work associated with the upper and lower torso- Rectus Abdominis and Lumbar Erector . Rectus Abdominisor abs, works with other abdominal muscles to control the pelvic tilt and plays a significant role in core stability. The erector spinae (lumbar, thoracic, and cervical regions) facilitates head and back extensions by bilateral contraction, controls the thoracic flexion and provides core strength. A multitude of reports about back pain associated with heavy backpack carriage in children 16– 19 further bolsters the importance of this muscle. A study by Mosaad and colleagues explored the effect of load carriage on the trapezius muscle of 30 school going children (mean age -13.66years). Muscle activity was observed in 3 separate instances, one when the children had no load to carry, in the other two the kids were asked to carry an ordinary backpack and an ergonomically designed double sided pack. It was observed that the muscle activation was significantly less when the kids were carrying the ergonomically 2 Year 2022 Global Journal of Medical Research Volume XXII Issue IV Version I ( D ) K © 2022 Global Journals Investigating the Facets of Physical Activity Related to Schoolbag Carriage- Highlighting the Lacunae that Exists