Muscle strength is an indicator of human vitality. It fluctuates throughout the day, following a circadian pattern, and it also changes across a lifespan. Muscle strength increases until about 25-35 years of age after which it plateaus and then declines at a rate of about 10% per decade after the fifth decade of life. The rate of decline can differ based on patient’s sex and assessed muscle group.
Loss of muscle strength with aging is due primarily to reduced muscle mass (sarcopenia). Reduced muscle strength correlates with earlier mortality, increased risk of falls, and greater difficulty in performing activities of daily living. Thus, increasing or maintaining muscle strength is critical for living a long, healthy life.
The most effective way to increase or maintain muscle mass and strength is by participating in resistance exercise, such as weight training, or other muscle-strengthening activities. Resistance exercise is safe, and it creates many health benefits, including improved cardiovascular profiles, better walking and sit-to-stand ability, reduced anxiety and depression, and better quality of life.
For these reasons, professional exercise organisations in Australia and abroad have published position statements on resistance exercise participation for healthy aging and for inclusion in treatment plans for conditions such as diabetes, cardiovascular disease, cancer, and motor impairments like multiple sclerosis and spinal cord injury.
Public health bodies recommend that adults participate in resistance exercise or other muscle-strengthening activities two or more days a week. Professional exercise organisations then further specify that exercise sessions include multiple sets of 8-10 different exercises that target all major muscle groups.
Nevertheless, a significant number of Australians – roughly 60% – do not meet recommended guidelines for participation in muscle-strengthening activities. Similar results are observed in other countries.
Multiple factors contribute to low participation in resistance exercise. Key intrapersonal barriers include perceived lack of time, lack of exercise knowledge or confidence, not enjoying or prioritising exercise, and being ill or having a disability. Common social or environmental barriers include family and work obligations, financial costs, lack of access to exercise facilities or programs, and transportation and exercise location challenges.
Clinicians can help patients overcome some of these barriers by informing them that there is no single resistance exercise script that everyone must follow. Some script specifications are based on the patient’s preferences and circumstances. For example, muscles can be strengthened by using different types of resistance, including dumbbells, weight machines, elastic bands, and one’s own body weight. Also, resistance exercise can be performed in various locations such as at home, at the gym, at the park, and at treatment facilities.
Ideally, patients would achieve the recommended guidelines for resistance exercise each week. However, these guidelines should not preclude clinicians from also informing patients that ‘doing something is better than doing nothing’ when it comes to the exercise volume on the patient’s muscle-strengthening script.
Health and fitness benefits derived from physical exercise generally follow a dose-response relationship, whereby more weekly exercise causes greater benefits. However, fitness benefits still occur at the low end of the exercise volume spectrum. In fact, given that perceived lack of time is one of the most frequently reported barriers to exercise participation, and many individuals do not participate in any muscle-strengthening activities, researchers have started to explore the scientific credibility of minimal dose resistance exercise.
Minimal dose resistance exercise refers to a volume of exercise that does not meet recommended guidelines but that might still improve muscle strength. “Weekend Warrior” is one example. With this approach, training frequency is minimised. All weekly resistance exercise volume is completed in one session, often on a Saturday or Sunday, if an individual works full-time during the week.
Another example is resistance exercise ‘snacking’. Snacks reduce session duration. They are brief bouts of exercise (5-10 minutes) performed once or more daily on most, if not all, days of the week. Snacks would suit, for example, patients who work from home and own equipment like dumbbells or elastic bands.
Current evidence suggests that when these and other types of minimal dose programs are performed regularly over a few weeks, they improve muscle strength and some other outcomes of health and fitness. This is especially true for individuals who have no previous experience with resistance exercise.
Thus, resistance exercise is medicine…even in small doses.
Key messages
- Adequate muscle strength is important for daily life
- Resistance exercise, even in minimal doses, improves muscle strength
- Patients should be encouraged to participate in resistance exercise.
Author competing interests – nil