What does it mean to by physically fit? Depending on your workout of choice (or just your fitness goals), your definition might vary. An endurance athlete like a runner or a cyclist might say fitness is about going far and going fast. On the other hand, a weightlifter might think of fitness in terms of how many pounds they can bench or curl.
The reality is that these are factors in a much bigger picture—and true physical fitness depends on all of them, according to the American College of Sports Medicine (ACSM), a national organization that offers certification in exercise physiology and sets industry standards.
The five factors are cardiorespiratory efficiency, muscular strength, muscular endurance, flexibility, and body composition. Focusing exclusively on one factor while ignoring the others can leave your body imbalanced and not reaping the full benefits of physical activity. This is why trainers and physiologists encourage their clients to follow physical activity patterns that address all aspects of physical fitness.
If you want to self-evaluate your own exercise habits to determine whether you’re achieving real fitness per ACSM standards, here’s a quick explanation on each factor and how you can approach it:
Cardiorespiratory efficiency is what you often hear referred to as cardio. It’s aerobic exercise that raises your heart rate with the goal of improving your circulatory and respiratory systems. Cardio includes workouts like running, biking, and swimming, as well as less intense activities like walking. You should aim for at least 150 minutes of moderate cardio or 75 minutes of vigorous cardio every week.
Muscular strength is your ability to exert force against an object—in other words, your ability to move something heavy. People’s needs will differ in this regard, as some people want to be able to challenge themselves to lift as much weight as they can, while others simply want to maintain strength as they get older. Both are valid goals. Muscular strength is different from muscular endurance, which is defined as your ability to exert that strength for an extended period of time without tiring out.
To achieve muscular strength and muscular endurance fitness, you should be working all major muscle groups—your shoulders, arms, chest, abdomen, back, hips, and legs—at least twice a week. Use enough weight that you feel fatigued after performing a move for between five and 10 repetitions (often referred to simply as “reps” in fitness lingo). As you get stronger, you may choose to increase weight or do more reps. Lifting more weight for fewer reps will improve your muscular strength, and lifting less weight for more reps will improve your muscular endurance.
Flexibility refers to your range of motion across a joint—the broader your range of movement, the more flexible you are. Flexibility is an important part of fitness because it ensures proper use of muscles and reduces your risk of injury. Some physical activities, such as yoga or gymnastics, demand flexibility, but even simple stretches are a great way to become more flexible. Take 10 minutes during every workout to stretch each of your major muscle groups, moving into a pose as far as you can go and holding it for 10 to 30 seconds. To achieve greater flexibility, you can strive to push yourself farther into a pose with each workout.
The last component of fitness is body composition, which refers to your proportions of muscle, bone, fat, and water that make up your body. Although people refer to losing weight in regard to physical fitness, weight can be a misleading measurement, because individuals with large amounts of muscle mass will weigh more than someone with a less muscular body composition. Therefore, a muscular person could be categorized as “overweight,” even though they do not have a high level of body fat.
Fit people tend to have more muscle and less body fat, but experts have increasingly been emphasizing that individuals with high percentages of body fat still enjoy health benefits of regular physical activity. Organizations such as ACSM, as well as doctors at health centers like the Cleveland Clinic and the Mayo Clinic, note that carrying a higher percentage of body fat and lower percentage of lean body mass can strain the vascular system and skeletal system.
Want ideas on how to improve your fitness in all areas? There are many resources available through the American College of Sports Medicine, including exercises and explanations on the benefits of each. Visit acsm.org.
