None listed
Conditions
Brief summary
High-intensity interval training (HIIT) is becoming more widely recognized as a time-efficient alternative to traditional endurance exercise for improving markers of cardiopulmonary and metabolic health. A major benefit of HIIT is the time-efficiency of a single exercise session which can be completed in under 30 minutes. HIIT involves short, repeated periods of work at or above maximal aerobic capacity interspersed with rest intervals (e.g. 1 min work, 1 min rest repeated 10 times). Given that HIIT requires rapid contraction of type 2 skeletal muscle fibres, as seen with resistance exercise, it is possible that HIIT may also be able to precipitate muscle mass gains. Whether HIIT with protein supplementation can facilitate similar skeletal muscle adaptations reported following resistance exercise, such as hypertrophy, remains understudied in the literature. When an individual stops training (i.e. detraining), loss of adaptation from exercise can occur. However, no study to date has investigated the effects of a short-term (i.e. 2½ weeks) detraining period on measures of strength and aerobic fitness between resistance, endurance and HIIT training. The purpose of this study is to investigate the metabolic and anabolic effects of 6 weeks of HIIT with protein supplementation on measures of muscle cross sectional area, body composition, resting metabolic rate, blood glucose control, muscle architecture, maximal strength and aerobic capacity in overweight and obese adults. Study aims: 1. Compare the anabolic/muscle growth effects of six weeks of HIIT with protein supplementation vs resistance exercise with protein supplementation 2. Compare the metabolic effects of six weeks of HIIT with protein supplementation vs endurance exercise with protein supplementation 3. Investigate the metabolic and anabolic effects of a 2½-week detraining period following each of the exercise interventions Study hypotheses: 1. HIIT with protein supplementation will induce comparable increases in muscle fibre cross-sectional area, lean body mass, whole muscle transcriptome responses, muscle architecture, compared to resistance exercise with protein supplementation 2. HIIT with protein supplementation will induce comparable increases in insulin sensitivity, resting metabolic rate and mitochondrial protein content compared to endurance exercise with protein supplementation 3. Following a 2½-week detraining period, HIIT with protein supplementation will result in comparable losses in muscle cross sectional area, lean body mass, muscle thickness and muscle transcriptome responses compared to resistance exercise with protein supplementation 4. Following a 2½-week detraining period, greater losses in muscle cross sectional area, lean body mass, muscle thickness and muscle transcriptome responses will occur with endurance compared to HIIT exercise
Interventions
Brief name:
The metabolic and anabolic effects of 6 weeks of resistance (REX), endurance (END) and high intensity interval training (HIIT) with protein supplementation and the subsequent effects of 2.5 weeks of detraining.
Materials:
All people who wish to participate in the study will be provided with a copy of the Letter to Participants and a letter to their GP. Clearance from a GP is necessary as participants will perform maximal exercise testing. All participants will be provided with a cop
Brief name: The metabolic and anabolic effects of 6 weeks of resistance (REX), endurance (END) and high intensity interval training (HIIT) with protein supplementation and the subsequent effects of 2.5 weeks of detraining. Materials: All people who wish to participate in the study will be provided with a copy of the Letter to Participants and a letter to their GP. Clearance from a GP is necessary as participants will perform maximal exercise testing. All participants will be provided with a copy of the signed study consent form. Procedures: Participants will be asked to record their diet using a phone App to meet individual energy and protein (1.3-1.5 g/kg) targets as estimated from the baseline resting metabolic rate test. To assist with diet recording compliance, participants will be provided with a document stating their targets and will receive ongoing feedback in person once every 3 weeks from the study dietitian to ensure they are consuming enough food to assist with expected responses (e.g. increased lean mass) following the exercise interventions. One-on-one diet consults throughout the study will run for 15-20 min each. Participants will also receive high protein supplements (e.g. protein powder, yoghurt, energy bars) to improve adherence to the dietary protocol. On training days, participants will consume a protein shake containing 25-30 g of whey protein following all exercise sessions. On all days of the study, participants will be instructed to spread their protein intake across the day. Further, participants will be instructed not to drink alcohol on training days and restrict alcohol intake to two standard drinks on all days of the study. All exercise groups described will complete 3 sessions per week for 6 weeks with at least 1 day of recovery separating each session. Exercise sessions will be administered one-on-one or in small groups (2-3 people) depending on the time that each participants chooses to train. To monitor participation adherence, a register of attendance will be completed at every session and participants will be provided with electronic appointments to avoid scheduling conflicts. Participants will be stratified to one of the exercise interventions by lean muscle mass determined from the baseline body composition (DXA) scan. The principal investigator will be responsible for stratification. As the primary outcome of the study is change in muscle cross sectional area, similar baseline muscle masses between each of the groups is essential to avoid biased results post intervention. HIIT: After warming up at a light intensity for 3 minutes on an exercise bike, participants will perform 10 x 1 min cycling work efforts at 90% of peak power output (PPO) separated by 1 min recovery at 30 W. To finish the session, you will complete a light warm down for 3 min. The efforts will be increased in intensity progressively throughout the program. All exercise sessions will be take place in an exercise physiology laboratory supervised by a qualified exercise scientist. Detraining: No structured exercise will be allowed for 2.5 weeks following the exercise programs.
Sponsors
Dr Donny Camera
Study design
Allocation
Non-randomised trial
Intervention model
Parallel
Primary purpose
Prevention
Masking
Open (masking not used)
Eligibility
Sex/Gender
Male
Age
35 Years to 45 Years
Healthy volunteers
No
Inclusion criteria
Overweight or obese (BMI 25-35) Sedentary - less than 150 min of moderate intensity physical activity or 75 min of vigorous intensity physical activity per week. No type 2 diabetes Pass the Exercise and Sports Science Australia pre-exercise screening tool and obtain GP clearance to exercise No injuries preventing exercise
Exclusion criteria
Identified as high risk by GP despite passing all other inclusion criteria Currently losing weight Smoker Participation in structured exercise in the past 6 months Not willing to use phone App to record diet Had bariatric surgery in the past Vegan Hormone replacement therapy Shift worker
Outcome results
None listed