Effects of a Postural Education Multicomponent Intervention in Primary School Children.

Validated questionnaire with Spanish children (Cronbach's alpha = 0.82) will be used to ascertain children's' level of knowledge on back care in daily life physical activities. Specifically, this questionnaire has 24 multiple choice items associated with one of the following categories according to conceptual knowledge: topographicalanatomical knowledge (items 1, 2, 3 and 6); functional-anatomical knowledge (items 4, 5 and 7); habits in standing posture (items 8-10); or seated (items 11-13); or lying (items 23 and 24); habits in carrying heavy objects in a backpack (items 14-18); and how to move heavy loads (items 19-22).

Additionally, the questionnaire validated with Spanish schoolchildren and used in Méndez et al. will be used to assess back posture knowledge related to general principles of good body mechanics and fear-avoiding beliefs.

Daily life habits will be assessed by means of a questionnaire that will be fulfilled by the children. The questionnaire include the following items: being allowed to leave the academic material at school (yes=1/no=0), correct use of sofa (yes/no), stooping correctly (yes/no), take care to sit correctly at home (yes/no), take care to sit correctly at school (yes/no), frequent posture change on chair at home (yes/no), and frequent posture change on chair at school (yes/no).

Correct use of backpack will be assessed by means of a questionnaire that will be fulfilled by the children. The questionnaire include the following items: try to load the minimum weight possible, carry a backpack on two shoulders, belief that school backpack weight does not affect the back and the use of a locker or similar at school.

The weight of the children's' backpack will be also measured.

The instrument to evaluate LBP prevalence will be based using a validated questionnaire. Data related to LBP included in the questionnaire were the following: LBP experience during the student's lifetime (never, almost never, sometimes, often, always), LBP impeding usual activities (never, only when in pain, always), treatment received for LBP (no, rehabilitation, drugs, surgery, others), LBP in bed during the night or upon waking (yes, no), LBP during the last week (yes, no), LBP during or at the end of a physical education (PE) class (never, almost never, sometimes, often, always), diagnosis of scoliosis and diagnosis of different leg length (yes, no).

Low Back Pain Knowledge Questionnaire (LKQ) will be used as an instrument to assess knowledge about back pain in teachers. This questionnaire is composed of 16 questions, divided into the following categories: general aspects, concepts, and treatment. The total maximum score is 24 and is classified into one of three levels: low (0 - 14), moderate (15 - 18), and high (19 - 24).

The Quebec Back Pain Disability Scale will be used to assess daily postural habits of teachers. The scale exists of one central question: "Do you have trouble today with...?" followed by 20 activities of daily life. In every activity, there are 6 answer categories, measured by using a Likert scale from 0-5 (0 = no effort, 5 = not able to). The final outcome is obtained by the sum of the scoring of the degree of difficulty in performing the 20 daily activities. These outcomes score within the range of 0 and 100, determents the level of functional disability, with higher numbers representing greater levels of disability.