**1. Introduction**

Physical activity can be described as any deliberate bodily movement generated by the skeletal muscles requiring bioenergetics [1]. Physical activity can encompass all activities, at any intensity and includes both exercise and incidental (i.e., not planned, structured, repetitive, or purposeful) activity integrated into daily routine [2]. However, global physical activity guidelines and recommendations exist based on the amount of exercise required to reap the health benefits of physical activity. One such guideline advises that individuals aged 18 years and older should accumulate 150 minutes of moderate-intensity activity per week, or equivalent [3].

Regular physical activity involvement has been linked with a significant decrease in the risk for premature mortality. It has similarly been found to decrease the risks of more than 25 chronic conditions [4, 5]. Specifically, research has demonstrated substantial evidence that regular physical activity is related to a reduced risk for all-cause mortality and numerous chronic conditions such as cardiovascular disease, ischemic

heart disease, and ischemic stroke, type 2 diabetes, gestational diabetes, hypertension, breast cancer, colon cancer and gallstone disease [6]. Problematically, this guideline is overly simplistic because certain physical activity modalities have been demonstrated to promote health, contribute to disease prevention and rehabilitation in different ways and through different mechanisms.

In this regard, aerobic physical activity modalities have unequivocally been found to have significant cardiorespiratory benefits and reduce the incidence of and mortality from cardiovascular and metabolic diseases from multiple mechanisms including inter alia, anti-ischemic, anti-atherosclerotic, anti-thrombotic, and anti-arrhythmic, effects in addition to its psychological health benefits encompassing reductions in anxiety, depression, and stress [7]. In turn, resistance activities have been found to exert its own plethora of health-promoting and disease prevention benefits such as reducing low back pain, arthritic discomfort, while promoting functional independence and status, and mobility [8, 9]. Resistance activities have also been demonstrated to be the most superior exercise modality to increase metabolic rate, lean body mass and bone mineral density [9]. It is for this reason that resistance activities are now endorsed for inclusion into an all-inclusive physical activity programme by various global health organisations, including the American College of Sports Medicine, American Heart Association, and the American Association of Cardiovascular and Cardiopulmonary Rehabilitation and Surgeon General's Office [10]. As such, any physical activity programme aimed at improving health and preventing disease should focus on including regular aerobic and muscular fitness activities, as well as reducing time sedentary behaviour.

## **1.1 The pandemic of physical inactivity**

Globally, one in four adults (25%) do not meet these globally recommended levels of physical activity. This figure is even more alarming in the global adolescent population where more than 80% of adolescents have been found to be insufficiently physically active [3]. In the United Kingdom (UK), physical inactivity is linked to one in six deaths and costs the UK £7.4 billion annually. Unfortunately, the UK population is proposed to be approximately 20% less active than in the 1960s with projections that the population will be 35% less active by 2030 [11].
