Effects of 12-week dairy-derived nutritional supplementation combined with physical activity on health and physical function in healthy middle aged women after a 2-week period of reduced activity

Participants will be randomised into 2 treatment groups and progress through 2 phases (Phase 1 = 2 wk reduced activity; Phase 2 = 12 wk exercise + supplementation intervention). In Phase 1 the participants will aim to reduce their physical activity to below 1500 steps per day. During this period the participants will: (1) spend the majority of their day engaged in sedentary behaviour (i.e. activities with energy expenditure close to the resting level of 1.0-1.5 metabolic equivalent units (METs), including activities such as sleeping, sitting, lying down, watching television, and other forms of screen-based entertainment, (2) spend less than 90 min per day engaged in light activity (energy expenditure of 1.6-2.9 METs, including activities such as slow walking, cooking food and washing dishes), and (3) refrain from moderate and high intensity activity. Steps will be recorded each day using a pedometer to assess compliance. To determine energy expenditure across this period an accelerometer will also be worn daily (attached to the waist belt), and 7-day IPAQ questionnaires will be completed. A 3-day weighed diet record will also be completed, and testing will be completed, before and after this 2-week phase of reduced activity. In Phase 2, commencing immediately after Phase 1, the participants will begin supplementation with a fortified milk powder (FMP) or a placebo (PLA), and complete a 12-week structured physical activity (i.e. healthy lifestyle) programme that will include four training sessions a week: two university-based (strength, balance and flexibility training done in a group/social environment) sessions completed in small groups of up to 8 participants as well as two home-based (calisthenics, balance and flexibility training) sessions performed individually. The exercise programme will include elements of traditional strength and flexibility training programmes alongside aspects taken from yoga, Pilates, body balance and other popular forms of exercise. For the university-based gymnasium exercise program, the participants will complete 50 min of broad-based exercise training including muscle stretching, balance, muscle strength and physical fitness/endurance exercises. The sessions will commence with mobility and muscle stretching exercises (15 min). Fitness and muscle strength training will then follow, and the session will conclude with a short (5 min) stretch and warm-down period. Strengthening exercises (20 min) focusing on a holistic approach, but targeting the lower limb, will be incorporated into all sessions; examples include body-weight squat and lunge movements, although leg extension exercises performed on a machine will be incorporated. The strengthening exercises will be completed as a circuit format with 45 seconds work to 15 seconds of rest. Within those 45 seconds, 10-15 reps will be performed at an intensity of 14-15/20 RPE. For the fitness/endurance component (8 min per session), participants will perform stair climbing (4 and 3 min bouts with 1 min rest) or cycling, rowing and/or walking/running at a ‘moderate intensity’ in intervals with a 1:3 high- vs. low-intensity work ratio (e.g. cycle 15 s on level 12 then 45 s at level 4). All trainers will have a minimum of a degree level qualification in Exercise and Sport Science. At home the participants will perform a basic 20 - 30 min session that mirrors the movements and exercises performed in the gymnasium but which can be achieved without supervision or equipment. A reference sheet with photographic explanations will also be supplied as further reference. They will begin with a 10 minute warm up of active range of motion exercises, and then perform ~10 minutes bodyweight-resistance exercises. These resistance exercises cover 4 different movements. One set of each is to be completed to be completed to as many repetitions as possible. The intensity of these body weight exercises will therefore begin very light and then peak with a final repetition around 17-20/RPE. During Phase 2, the participants will also complete at least 3000 steps per day on ‘non-exercise’ days. In this phase of the project we will determine whether daily supplementation with a dairy-derived nutritional supplement provides greater health, mobility/physical function and vitality outcomes than physical activity alone, and thus whether this nutritional strategy might be adopted in 40 – 60 year-old women seeking to improve their health and well-being. The participants will be tested after 6 and 12 weeks of the programme. Phase 2 treatment arms: 1. Fortified Milk Powder, 30 g dose, 2 x per day; total dose 60 g/day [FMP]. The FMP supplement is largely comprised of milk powder (skim and whole), vitamins, minerals, complex milk lipids, maltodextrin and a small amount of hydrolysed fish collagen. It also contains low levels of Vitamins B12, B6, E and C. 2. Placebo, 30 g dose, 2 x per day; total dose 60 g/day [PLA] - see 'Comparator / Control treatment' for details. Assessment of compliance to supplementation The participants will receive their supplement (FMP or PLA) sachets in four installments, with a new batch every 3 weeks. The first group of sachets (along with ingestion guidelines) will be dispensed to the participants at the first testing session prior to Phase 2. To ensure supplementation compliance, the participants will be required to return all used and unused sachets every 3 weeks. A log of the sachets dispensed (out) and sachets returned (in) will be kept for each participant and the balance calculated.