1. A single time measurement after a backpack challenge would give an idea of postural compensation during that point in time. Changes in theses angles are a measure of body’s self regulatory response to stabilize the posture when challenged with back pack load(2). Once the backpack is removed, the angles come back to normal. So, the long term outcome cannot be predicted with this alone and conclusions cannot be drawn.

2. A better measure of predicting long term morbidity than the ‘weight of backpack’ is the ‘duration of carriage’. Logically, longer duration of carriage can theoretically have an effect on the musculoskeletal system. Authors have not mentioned anywhere regarding the ‘duration of carriage’ and its effect on the angles and outcome.

3. Justification for choosing ‘backpack weight in relation to bodyweight’ rather than absolute weight is not clear. The change in postural angles to backpacks are influenced by height rather than weight of a child. In an obese child, this would have lead to a challenge with comparatively more heavy backpack and vise versa. Therefore, the values obtained are not comparable.

4. Malnutrition (both underweight and obesity) would have significantly altered the subcutaneous fat and would have influenced the values of angles.

5. The term ‘back pain’ is too nonspecific. The authors should have mentioned about the possible specific structures which could get injured with carrying back packs.

6. Authors have also mentioned that ‘musculoskeletal problems associated with carrying heavy backpack’. They must clearly specify what ‘problems’ they mean with references.