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Osteogenic Exercise for Musculoskeletal and Metabolic Health during Weight Loss in Sarcopenic Obese Older Adults: A Pilot Study (OSMOSIS-P)
During the 12week intervention period, all participants will follow the dietary intervention prescribed and supervised by a licensed dietician with 11 years experience in the field, Equal numbers will be randomised to either gym-based High Intensity Resistance and Impact Training (HiRIT) or home-based aerobic exercise(control) as described below.
To determine the amount of energy in the diet that will be prescribed to each participant, habitual dietary nutrient intake will be assessed using a pre-tested 3-day food record form (two non-consecutive weekdays and one weekend) before the commencement of the study intervention. To complete the food record, study participants will list all the foods and beverages that they have consumed for the whole day, including quantities. From these data, each participant’s diet will be modified by deducting 750 - 1000 kcal from their habitual intake, aiming for at least ~1.0 kg reduction in total body fat per week. Three day food records will be administered at baseline and 12 weeks to constantly monitor the dietary intake of the participants and to ensure compliance. Each participant will be oriented by the study dietician on how to quantify their intake using food models and measuring utensils, as well as on how to reduce food portion sizes and replacing energy-dense foods with those of lower energy density. Food records will be validated by the study investigators through one-on-one interview with the study participant at each time point. Dietary nutrient intake of subjects will be processed using FoodWorks 8 Professional for Windows (Xyris Software (Australia), Pty Ltd), which uses the latest Australian Food and Nutrient Database (AUSNUT) 2011-2013 (FSANZ, 2014). AUSNUT is a database which contains 53 nutrient values for 5740 foods and beverages. The study dietician will conduct telephone interviews every week throughout the intervention to monitor and review dietary intakes and set behavioural goals. Participants with poor dietary compliance, as demonstrated by deviations from the diet prescription during the telephone interviews, will be given a 7-day dietary plan to ensure compliance.
Whey protein isolate and vitamin D (cholecalciferol; 1000 IU/day) supplements will also be provided to ensure adequate intakes of this important nutrient for musculoskeletal health is maintained during dietary restriction. The whey protein isolate will be in powdered form that can be mixed with skim milk or water as the participant prefers. The dose will vary for each participant throughout the intervention as it will be modified based on their estimated current protein intake (reported in food records) to ensure they are meeting a protein intake of 1.0g/kg/day. Vitamin D + calcium supplement will be in capsule form that will be taken orally.
Treatment: High Intensity Resistance and Impact Training
Participants allocated to the HiRiT group in the present study will be given a structured 12week, twice weekly, 30minute, supervised, gym based HiRIT program. Each participant will be encouraged to attend each supervised session by an accredited exercise physiologist at the local gymnasium, Healthwise, at Monash Medical Centre, Clayton and will not be required to pay an entry fee to attend; gym fees will be covered by the study budget and have been negotiated at $5 per exercise session during off peak hours (midmorning and midafternoon). Each exercise session will be performed in small groups with a maximum of 8 participants and attendance will be recorded via an exercise sheet. All exercises will be individually tailored and progressive, considering initial fitness, injuries or illness. The prescribed exercise program will use pinloaded smith machine bar or an olympic bar +/weight plates unless contraindicated. Participants will perform up to 2 sets of 5 repetitions of all four exercises at 50% of 1 Repetition Maximum (RM) to serve as a warmup at each session as required. Participants will be then required to perform 5 sets of 5 repetitions, at an intensity of >80% to 85% 1 RM. Each participant will be encouraged to increase the load of the four prescribed exercises each session while maintaining the desired intensity if able. All participants will be individually prescribed four fundamental exercises (deadlift, overhead press, and back squat and modified jumping chin ups) throughout the intervention period. To ensure safe transition to HiRIT exercise, the first two weeks of the intervention will involve body weight only and low load exercise variants, with a focus on learning the movement patterns. All participants will be able to perform the four fundamental exercises of the intervention within 4 weeks. Adherence to intervention will be determined through session attendance checklists and accomplished exercise diaries which will be reviewed during weekly followup calls throughout the intervention.
The control group will complete a moderate intensity, home-based aerobic exercise program. Participants will aim to progress to 150mins/week of walking/jogging at moderate intensity, based on self-perceived exertion reported on the Borg scale, and maintain this for the duration of the home-based intervention. This exercise program is modelled on the Lifestyle Interventions for Elders project and we have used it in previous studies in similar populations. Participants will be asked to complete exercise diaries to assess compliance and these will be reviewed during weekly followup calls throughout the intervention.