What Is Muscular Strength and How Is It Measured?
Definition of Muscular Strength
Muscular strength is defined as the maximum amount of force that a muscle can exert against some form of resistance in a single effort.
This is in contrast to muscular endurance, which represents multiple muscle contractions or a sustained muscle contraction over a period of time, for example during running, climbing or performing multiple reps with a dumbbell at the gym.
Practically speaking, you use muscular strength when you lift yourself out of a chair, pick up a heavy object, or push a piece of furniture. In the gym, a single repetition at a given weight is an example of muscular strength.
Does Increased Muscular Strength Mean Larger Muscles?
While there is a correlation between increases in muscular strength and muscle size (hypertrophy), that correlation is not necessarily proportional.
For example, Olympic weight lifters are very strong, yet often do not exhibit the same large musculature of a professional body builder. This is because Olympic weight lifters train primarily for single heavy lifts, while body builders utilize multiple reps (typically in the 6-8 rep range) — which builds some strength, but tends to bias an increase in muscle size.
Muscular strength is typically developed through both neural adaptations (improvements in how the central nervous system sends signals to the muscle to contract) as well as adaptations to the muscle tissue itself during and after training.
How Is Muscular Strength Measured?
Muscular strength is typically measured using what’s known as a One Rep Max (1RM). Your 1RM is the maximum amount of weight that a given muscle can move for one complete repetition. So, for example, to measure the muscular strength in your bicep, you would perform a single dumbbell bicep curl for one rep with an amount of weight that you can move for one complete contraction, and no more.
If you are used to performing multiple repetitions with a particular amount of weight, you may not know what your actual 1RM is. Also, there is a greater risk of injury associated with performing single repetition movements with a high-load, so testing your muscular strength with a 1RM can be dangerous.
Estimating Your One Rep Max (1RM)
There are a number of formulas you can use to estimate your 1RM based on how much weight you can move for multiple repetitions. The most well-known is the Brzycki Formula:
1RM = (Weight Used) x 36 / (37 – Number of Reps)
So, let’s take the bicep example again. Suppose you can perform 8 bicep curls at 45 lbs. You’re 1RM would be calculated like this:
45 x 36 / (37-8) = 55 lbs (1RM)
Although this will not be 100% accurate, it will give you an estimated starting point if you wish to perform an actual 1RM test. If you choose to do this, always make sure you are warmed-up properly and have a spotter.
Ways to Build Muscular Strength
Muscular strength is increased by performing progressively heavier resistance or weight training over time. While exercising with a weight that allows you to perform 6-8 repetitions before “failing” will build both muscular strength, muscle size and some muscle endurance, training with a level of resistance that causes you to fail in the 1-4 rep range is generally recognized as the ideal range for building muscular strength.
Benefits of Muscular Strength
Although the most obvious benefit of muscular strength is that it allows you to be able to perform basic activities each day, increasing your muscular strength has other benefits for both men and women, including:
- Reduced stress on joints
- Increased connective tissue strength
- Improved posture
- Increased insulin sensitivity, which may help prevent Type II diabetes and Metabolic Syndrome
- Decreased risk of obesity, especially when combined with improvements to cardiovascular endurance
- Improved body composition due to higher lean tissue to fat ratios
- Reduced risk of osteoporosis/increased bone density
Increased muscular strength can also help improve athletic performance as well as prevent injury, especially as you age.
Category: Fitness, Health & Exercise Glossary