The Effects of Strength and Balance Training on Physical Function in Overweight Children

The Effect of Strength and Combined Balance Training Intervention Programme on Physical Function, Physical Activity, and Musculoskeletal Health in Children With Overweight and Obesity

This intervention study aims to examine the efficacy of a school-based exercise programme to improve strength and balance in overweight and obese 7-11-year-olds in the United Kingdom. The main question[s] it aims to answer are: Is the school-based exercise programme effective in improving lower limb muscular strength and balance control? How do increases in strength and balance skills impact physical function, the risk to musculoskeletal health, and physical activity? Participants will attend baseline, post-intervention, and follow-up testing that includes assessment of strength, balance, 3D gait, plantar pressure, physical function and physical activity. The intervention group will take part in physical activity sessions in their school for 1 hour twice a week for a total of 8 weeks. Researchers will compare the intervention group to a control group that will take part in no-activity sessions and carry out their normal school and seasonal activities.

Body mass index will be calculated as body mass (kg) / height (m)2. Body mass will be measured using weighing scales and height by stadiometer whilst participants are barefooted with simple clothing (shorts and t-shirt). Z-scores denote the standard deviations that BMI for gender and height are from the mean of United Kingdom child reference curves. A higher z-score means greater BMI than the mean for child gender and height.

Bioelectrical impedance will be used to determine whole-body impedance. Population-specific equations will be applied to estimate body fat (kg). The percentage of body fat will be calculated as (Fat Mass (kg)/Body Mass(kg))*100.

Bioelectrical impedance will be used to determine whole-body impedance. Population-specific equations will be applied to estimate body fat (kg). Fat-free mass will be calculated as Body Mass (kg) - fat mass (kg).

Joint angles, moments, and power waveforms of hip, knee and ankle in three dimensions during the stance phase of self-paced walking. Change in lower limb 3D gait will be determined via a previously validated marker set for obese children, time normalised to 100% of stance phase, and moment and power will be dimensionless normalised to body mass and leg length.

The angle of the forefoot, midfoot, rearfoot and shank in three dimensions during the stance phase of self-paced walking. Change in foot 3D gait will be determined via a previously validated marker set for obese children, and time normalised to 100% of the stance phase.

Isokinetic dynamometry will be used to determine the maximal strength of hip extension, hip flexion, hip adduction, hip abduction, knee extension, knee flexion, ankle plantarflexion, and ankle dorsiflexion. Maximal moments will be allometrically scaled to body mass.

Isokinetic dynamometry will be used to determine the maximal strength of hip extension, hip flexion, hip adduction, hip abduction, knee extension, knee flexion, ankle plantarflexion, and ankle dorsiflexion. Maximal moments will be allometrically scaled to fat-free mass.

The maximal number of times participants are able to stand up and sit down in one minute. The stool used will be adjusted so the participant's knee is at 90 degrees when seated, and arms will be placed across the chest.

The time (seconds) it takes participants to stand from seated (knees 90 degrees), arms across chest, walk 3m turn and go back to seating.

The maximum amount of time participants are able to maintain stance on their dominant limb with the non-dominant limb flexed 90 degrees and hands held on the waist. The test is stopped when the non-dominant limb touches the ground, participants move their hands or dominant limb to maintain balance.

The maximum amount of time participants are able to maintain stance on their dominant limb with the non-dominant limb flexed 90 degrees and hands held on the waist and with their eyes closed. The test is stopped when the non-dominant limb touches the ground, participants move their hands or dominant limb to maintain balance.

Tri-axial accelerometry will be used to determine physical activity over three days (including one weekend day). Child-specific cutoff equations will be used to determine times of sedentary behaviour. Total time in mins will be divided by total wear time to get percentage of time in sedentary activity.

Tri-axial accelerometry will be used to determine physical activity over three days (including one weekend day). Child-specific cutoff equations will be used to determine times spent in moderate to vigorous physical activity. Total time in mins will be divided by total wear time to get the percentage of time in moderate to vigorous activity.

Tri-axial accelerometry will be used to determine physical activity over three days (including one weekend day). Vector magnitude counts are a total raw measure of movement.

Previously validated Paediatric Quality of Life (PedsQL; physical function section only) will be completed on a 5-point Likert scale and scored. Items are reversed, scored and linearly transformed to a 0-100 scale as follows: 0=100, 1=75, 2=50, 3=25, 4=0. If more than 50% of the items in the scale are missing, the scale scores should not be computed; mean score = Sum of the items over the number of items answered. A higher score denotes a better quality of life whilst a lower score suggests a poorer quality of life.

Previously validated paediatric pain questionnaire visual analogue scale for present pain. 10cm (100mm) visual analogue scales from 0 (Not hurting / No discomfort / No pain) to 10 (100) (Hurting a whole lot / Very uncomfortable / Severe pain). The value will be presented as mm from 0. A higher value means greater pain is present.

Previously validated paediatric pain questionnaire visual analogue scale for worst pain in last seven days.10cm (100mm) visual analogue scales from 0 (Not hurting / No discomfort / No pain) to 10 (100) (Hurting a whole lot / Very uncomfortable / Severe pain). The value will be presented as mm from 0. A higher value means greater pain is present.

Previously validated 16-item 5-point Likert scale from 1 (I disagree a lot) to 5 (I agree a lot). Negatively worded sites are reverse scored, and the overall enjoyment for physical activity score is determined by summing all items. A higher score means greater enjoyment of physical activity.

Previously validated 18-item 5-point Likert scale from 1 (I disagree a lot) to 5 (I agree a lot). An average score for each subdivision of autonomy, competence, relatedness and teacher relatedness is calculated. A higher score means positive support felt for each subdivision.