Effect of a Home-based REsistance Exercise vs a Home-based FLEXbility Exercise Programme on Muscular Endurance and Flexibility in Healthy Adults

Regular resistance training can lead to a variety of health benefits including increases in muscle size and strength, reductions on body fat, increased metabolic rate, glycaemic control, decreased blood pressure and improved blood lipid profiles. Because of this, current physical activity guidelines recommend undertaking muscle strengthening activities involving major muscle groups two days a week or more, alongside at least 150 minutes per week of moderate intensity physical activity (or 75 minutes per week of vigorous intensity physical activity). However, only small portion of the population achieves the muscle strengthening aspect of the guidelines.

Why participation in muscle-strengthening exercise is low is not clear but people identify several barriers including the lack of time, the effort involved, lack of purpose, pain due to injury, negative experiences of prescriptive exercise, apathy, illness, injury inclement weather and work commitment. In addition, some women have expressed a worry of looking 'manly' or 'bulking up' if they undertake resistance exercise. A further potential barrier is lack of access to a gym with appropriate equipment to perform resistance exercise, or dislike of a gym setting. Thus, identifying approaches to find a safe, enjoyable and accessible programme that minimises the burden of performing resistance exercise, and identifying a minimal amount of resistance training which can provide benefits is a key issue which could help more people to undertake muscle strengthening exercises.

Meta-analyses indicate that while performing resistance exercise two or more times per week of resistance exercise per muscle group appears to be optimal to maximise strength gains, a single set of resistance exercise per muscle group per week, if performed to failure is sufficient to induce substantial strength changes.

The main aim of this study is to compare the effects of an app-based home-based resistance exercise programme vs a home-based flexibility programme on muscular endurance (number of press-ups, time achieved in half-squat test, and time achieved in plank test, assessed online during a zoom call) and flexibility (sit and reach, assessed online during a zoom call) in healthy adults. Secondary aims are a) to determine participants' adherence to both exercise programmes, b) to determine participants' choice of weekly exercise volume (compared to minimum prescription) in both exercise programmes c) to determine participants' distribution of exercise throughout the week in both exercise programmes d) to determine the effects of a exercise programmes on well-being, and finally e) to determine participants' perceptions, feelings, thoughts, enjoyment, tolerance and acceptability of both exercise programmes.

The study is a randomized control trial in which the flexibility exercise group will undergo a 12-week home-based flexibility exercise programme. The resistance exercise group will undergo a 12-week home-based resistance exercise programme. Participants will be asked to perform a minimum amount of resistance or flexibility exercise of 1 set/week for each of six exercises and will have the opportunity to increase their volume of exercise to 2 sets or 3 sets/week per exercise if it is their choice. In addition, participants will be able to distribute the exercises during the week according to their preference (all in one day or spread over several days of the week, etc.). Participants will be encouraged to have a minimum of one day of rest per week.