Effects of Home Exercise Intervention on Bone Density, Muscle Functions, QoL, and Curve Progression in Girls With AIS

Areal BMD (g/cm2) of non-dominant femoral neck and greater trochanter, and whole body BMD will be measured by DXA (Horizon, Hologic Inc., USA). Standardized scanning procedure provided by the manufacturer will be followed to ensure unified and comparable measurement. Quality assurance is performed by daily calibration against the standard phantoms provided by the manufacturer, with a precision error of 1.9% for BMD value for patient scan and <1.0% for whole body phantom scan.

Muscle mass will be measurement by whole body less head (WBLH) scan with DXA (Horizon, Hologic Inc., USA). DXA is the current golden standard to the measurement of body composition. Standardized scanning procedure provided by the manufacturer will be followed to ensure unified and comparable measurement.

Body height, weight, sitting height, and arm span will be measured with standard stadiometry techniques.

BMC (g/cm) of non-dominant femoral neck and greater trochanter, and whole body BMC will be measured by DXA (Horizon, Hologic Inc., USA). Standardized scanning procedure provided by the manufacturer will be followed to ensure unified and comparable measurement.

A long standard standing postero-anterior (PA) whole spine radiograph will be used for grading curve severity in terms of Cobb angle according to the standard Cobb method. Risser sign, curve level and apex, and curve type will be recorded as in any standard assessment of scoliosis patients.

A long standard standing postero-anterior (PA) whole spine radiograph will be used for grading curve severity in terms of Cobb angle according to the standard Cobb method. Risser sign, curve level and apex, and curve type will be recorded as in any standard assessment of scoliosis patients.

Legs, back, abdominal, and handgrip muscle strength will be assessed with dynamometer. The tests will be performed 3 times with 1 familiarization effort and 2 maximal effort, and the highest scores will be used for analysis.

Legs, back, abdominal, and handgrip muscle strength will be assessed with dynamometer. The tests will be performed 3 times with 1 familiarization effort and 2 maximal effort, and the highest scores will be used for analysis.

Isometric squat test, Biering-Sorensen test, and isometric curl-up test will be used to assess the quadriceps, back and abdominal muscle endurance. The time (seconds) in which the subject maintained the position is recorded.

Isometric squat test, Biering-Sorensen test, and isometric curl-up test will be used to assess the quadriceps, back and abdominal muscle endurance. The time (seconds) in which the subject maintained the position is recorded.

Aerobic fitness (estimated VO2max) of the subjects will be measured using sing-stage cycle ergometer sub-maximal test. Participants will be asked to sit on a cycle ergometer with 3-5 min warm up cycling at 150 kgm/min (25 Watt) workload, then workload will increase to 450-600 kgm/min (75-100 Watt) for another 6 minutes, in order to stimulate a submaximal exercise heart rate between 125-170 bpm. Estimated VO2max is then computed from the Astrand formula: VO2max = (workload x 2 + 300) * (200 - 73) / (exercise heart rate - 73)". Safety guidelines and procedures recommended by the ACSM will be followed.

Aerobic fitness (estimated VO2max) of the subjects will be measured using sing-stage cycle ergometer sub-maximal test. Participants will be asked to sit on a cycle ergometer with 3-5 min warm up cycling at 150 kgm/min (25 Watt) workload, then workload will increase to 450-600 kgm/min (75-100 Watt) for another 6 minutes, in order to stimulate a submaximal exercise heart rate between 125-170 bpm. Estimated VO2max is then computed from the Astrand formula: VO2max = (workload x 2 + 300) * (200 - 73) / (exercise heart rate - 73)". Safety guidelines and procedures recommended by the ACSM will be followed.

The Quality of Life of the subjects will be assessed with the official Chinese version of Scoliosis Research Society-22 (SRS-22r) Questionnaire. SRS-22r is an internationally validated questionnaire that contains 22 questions organized in 5 domains covering different aspects of the quality of life of patients with scoliosis: function/activity, pain, self-image, mental health (5 items each), and satisfaction with treatment (2 items).

The Quality of Life of the subjects will be assessed with the official Chinese version of Scoliosis Research Society-22 (SRS-22r) Questionnaire. SRS-22r is an internationally validated questionnaire that contains 22 questions organized in 5 domains covering different aspects of the quality of life of patients with scoliosis: function/activity, pain, self-image, mental health (5 items each), and satisfaction with treatment (2 items).

Areal BMD (g/cm2) of non-dominant femoral neck and greater trochanter, and whole body BMD will be measured by DXA (Horizon, Hologic Inc., USA). Standardized scanning procedure provided by the manufacturer will be followed to ensure unified and comparable measurement. Quality assurance is performed by daily calibration against the standard phantoms provided by the manufacturer, with a precision error of 1.9% for BMD value for patient scan and <1.0% for whole body phantom scan.

BMC (g/cm) of non-dominant femoral neck and greater trochanter, and whole body BMC will be measured by DXA (Horizon, Hologic Inc., USA). Standardized scanning procedure provided by the manufacturer will be followed to ensure unified and comparable measurement.

Muscle mass will be measurement by whole body less head (WBLH) scan with DXA (Horizon, Hologic Inc., USA). DXA is the current golden standard to the measurement of body composition. Standardized scanning procedure provided by the manufacturer will be followed to ensure unified and comparable measurement.

Body height, weight, sitting height, and arm span will be measured with standard stadiometry techniques.

The recruitment rate will be calculated based on the number of eligible subjects invited to the study and the number of eligible subjects agreed to participate.

The dropout rates for the intervention and control groups will be calculated based on the number of recruited subjects in each group and the number of recruited subjects who failed to complete the 6-month exercise and complete all follow-up.

Evaluation of habitual dietary intake will be based on retrospective means of assessment. A modified Food Frequency Questionnaire (FFQ) based on data obtained in the Hong Kong Adult Dietary Survey in 1995 will be used. The FFQ had been validated with the basal metabolic rate calculation and the 24-hour sodium/creatinine and potassium/creatinine analysis. Subjects will be asked about their usual frequency and consumption in the past twelve months from the food list. Standard portion size will be listed and a food photo album is provided to assist assessment. Any use of supplements will also be recorded. Daily nutrient intake is calculated by the Food Processor Nutrition analysis and Fitness software version 8.0 (Esha Research, Salem, USA), with addition of composition of some local foods based on food composition table from China.

Physical activity level will be assessed with a physical activity bracelet and questionnaire. The subjects will be asked to wear the physical activity bracelet every day during the study period, thus provide an objective assessment of the physical activity of the wearer. Physical activity level of the subjects will also be assessed with the modified Baecke questionnaire adapted from Pols et al.

Sexual maturity level including the breast development, onset of menarche, pubic hair distribution will be graded with standard Tanners Scale using the established and validated protocols.