Power fades before strength as we age. Scientists are trying to find out why—and how to push back
As a dabbling marathon runner, I’m no stranger to the slow-twitch muscle fiber shift that comes with endurance training. But with each passing year, the changes in my muscle response are becoming more pronounced. The explosive power I once summoned to pick up gears now feels just out of reach, replaced by a seasoned—but undeniably different—musculoskeletal system. This isn’t just me, either. Declining muscle power is a characteristic of aging, particularly noticeable in our forties and beyond. And that’s a real problem because muscle power—not just strength—is one of the strongest indicators of how well we’ll manage everyday activities later in life, like standing up from a seated position, walking up a flight of stairs, or getting out of a car without falling sideways.
Despite its critical importance, scientists are still unraveling why power declines so steeply with age. Two recent pieces of research—a review from the Karolinska Institute published in the International Journal of Molecular Sciences and a study from Marquette University published in the Journal of Applied Physiology—recently shed light on this question, offering insights into the biological mechanisms of power loss and, crucially, what we might be able to do to combat it.
Why Muscle Power Matters and Why We Lose It Faster Than Strength
Muscle power is the intersection of force and speed—how much strength you can apply and how quickly you can mobilize it. Unlike pure strength, which is simply the ability to exert force, power is dynamic, adding the element of velocity. Everyday actions, from stepping up onto a curb to recovering from a near-fall, rely on this explosive power. Research highlights that power is often a more telling predictor than strength alone for how well we’ll handle these movements as we age. With power in decline, tasks like these can gradually shift from manageable to daunting.
The truth is, muscle power declines more rapidly with age than muscle strength. Peak performance generally occurs between ages 25 and 30, but the descent often starts in our 30s. By age 40, muscle mass typically decreases by about 0.5 to 1 percent each year, while power drops nearly twice as fast—around 2 to 4 percent annually. By our 60s and 70s, this accelerated decline significantly impacts daily life. This loss of power is largely due to the reduction in fast-twitch muscle fibers, essential for quick, forceful movements. As these fibers diminish, the muscle composition shifts toward slower, endurance-oriented fibers that can’t generate the same rapid force.
(Photo: International Journal of Molecular Sciences)
A comprehensive review from the Karolinska Institute, published in the International Journal of Molecular Sciences, digs into the underlying biological processes behind this decline. Age doesn’t just diminish individual muscle fibers; it disrupts the entire system supporting muscular coordination and strength. Each fiber depends on motor neurons—cells responsible for relaying the electrical impulses needed for contraction. With age, some of these neurons degenerate or die, leaving certain muscle fibers “orphaned” from their neural pathways. Though nearby neurons may attempt to “adopt” these fibers, the resulting motor units become larger and less precise, impairing both muscle control and strength. This deterioration isn’t just a matter of muscle mass; slower neural signals mean that muscles contract less efficiently, undermining balance and complicating even routine actions. Complicating this further, the extracellular matrix (ECM)—a structural support around the muscle fibers that connects them to tendons and bones—stiffens with age, impairing flexibility and coordination. The ECM’s increasing rigidity underscores why preserving power, not merely strength, is essential for maintaining functional independence as we grow older.
(Photo: Journal of Applied Physiology)
Building on this, a study conducted by Marquette University researchers, led by Christopher Sundberg, explored how neural and muscular factors contribute to power decline across age groups in both men and women. Published in the Journal of Applied Physiology, the research assessed maximum power in the quadriceps of young adults (average age 23), older adults (average age 70), and very old adults (average age 86). Participants, seated with bent knees, were instructed to extend their legs as powerfully as possible. As anticipated, muscle power showed a steep decline with age, outpacing the loss in muscle strength. However, the nervous system's ability to trigger strong contractions remained relatively stable, even among the oldest participants.
The study’s results indicate that the primary source of power loss with age lies within the muscles themselves. With age, muscles accumulate fat and scar tissue, tendons lose elasticity, and muscle fibers react more sluggishly. Sundberg’s team suggests that a key driver is the accelerated loss of fast-twitch fibers, which are essential for explosive movements and diminish more rapidly than slow-twitch fibers. This shift results in aging muscles that struggle to generate quick, powerful actions, emphasizing that the decline in power stems mainly from muscular—not neural—changes as we grow older.
Practical Strategies for Maintaining Muscle Power as You Age
The studies focus on why we lose muscle power, but my takeaway is this: if you want to hold onto as much explosive power as possible, you have to train in ways that demand speed and power. Moving in explosive ways can help counteract the the loss of natural decline.
To maintain muscle power, incorporating exercises that demand quick, powerful bursts is essential. Movements like hops, bounds, box jumps, explosive push ups, ball slams, and even hill sprints, specifically target fast-twitch fibers, which are crucial for power. Additionally, focusing on speed in strength training—by lifting lighter weights with fast, controlled reps (around 50-60% of your one-rep max)—can also help engage these fast-twitch fibers. This type of training, often called “power training,” emphasizes both strength and speed. Maintaining a baseline of strength is also important, as basic strength supports power. Regular resistance training that includes heavier, low-rep sets, when appropriate, can help keep muscles robust and prepared for quick movements.
Balance and flexibility exercises are another valuable addition to a power-preserving routine. Balance work, such as single-leg stands, along with flexibility practices like yoga or stability exercises, provides a solid foundation that reduces the risk of injury. These types of exercises help with coordination and support more dynamic movements later on. Additionally, it’s important to avoid prolonged inactivity, as muscle strength and power fade quickly, particularly after illness or injury. Staying active and gradually reintroducing exercise after any break can help prevent rapid losses in muscle function.
Finally, nutrition plays a critical role in muscle health. A diet rich in protein provides the building blocks necessary for muscle repair and growth. Essential nutrients like vitamin D, calcium, magnesium, vitamin K2, and omega-3 fatty acids also contribute to muscle health and support overall function, particularly when combined with regular exercise. This combination of power-focused exercise, strength maintenance, balance and flexibility work, and supportive nutrition can help you preserve muscle power and move into later years with greater confidence and resilience.
For us aging athletes, muscle memory alone isn’t enough to keep us powerful. Those familiar movements need a little more intention now to stay sharp and explosive. You’ll find me adding in some jumps, hops, and bounding into my routine, along with some speedier power moves with my resistance training. Aging may be inevitable, but with some focused training adjustments, we can keep that explosive edge going—and while age might add some notches of experience, it doesn’t have to take away our power so quickly.