It's a depressing fact, but shortly after age 50, you begin to lose nearly 2 percent of your muscle fibers each year. Figure 1 is a graph of the average number of quadriceps muscle fibers present in adults ages 18 to 82.1 Looking at the center of the graph, you can see how the number of muscle fibers remain stable through your 30s and 40s. After that, muscle mass declines rapidly, dropping from 600,000 muscle fibers at age 50 to 320,000 muscle fibers by age 80.
Unfortunately, this reduction in muscle mass is associated with a threefold reduction in strength and power, which begins a downward spiral of frailty that correlates strongly with disability, falls and reduced lifespan.2 Several studies have shown that age-related muscle loss (also known as sarcopenia) is associated with the development of osteoarthritis, heart disease, stroke, diabetes, hypertension, cognitive decline and even cancer.3-5
Exercise for Muscle Preservation: The Problem With Heavy Repetitions
While research confirms that regular exercise can reduce the speed of muscle wasting, there is a surprising amount of controversy regarding what type of exercise is best for maintaining muscle mass. According to the American College of Sports Medicine, the only way to effectively build muscle is to perform multiple sets of 8-12 repetitions using heavy weights.6
The theory is that heavy weights are needed to recruit the maximum number of muscle fibers in order to stimulate remodeling. The problem with using heavy weights is that as people age and muscle fibers begin to disappear, the vanishing muscle fibers are replaced with fat and scar tissue, which significantly weakens muscles and tendons.7 Age-related weakening of muscle fibers explains why seniors are 10 times more likely to be injured while lifting heavy weights compared to their younger peers.
A Better Option: Light Resistance
Fortunately, a growing body of research shows it is possible to build muscle mass using light resistance exercise. In 2013,8 researchers compared changes in muscle volume in subjects who performed conventional high-resistance two-weight training (two sets of 10-15 reps performed at near full effort), with subjects who performed one set of 60 repetitions at 15 percent of full effort, followed immediately with one set of 12 repetitions performed at 40 percent full effort (i.e., the subjects were exhausted after the 60th and after the 12th repetition, respectively).
The researchers were surprised that the low-intensity routine produced the same gains in muscle volume as high-intensity weight training. They state that prior to their study, "virtually no studies have focused on the effects of such high-repetition protocols."
In 2018, researchers from Japan had 88 men and women ages 70 years or older participate in a weight-training program in which they performed two sets of 10-14 repetitions daily for 12 weeks.9 The subjects used body weight alone and performed the movements very slowly (four seconds up and four seconds down).
At the end of the 12-week training program, in addition to significant increases in muscle mass, participants also had decreased hip and waist circumference and reduced abdominal fat. This study is remarkable because the participants had no prior experience with weight training, the exercises were performed at home (taking less than 15 minutes each day), and at the end of the study, only two of the 88 people involved had dropped out.
In a 2019 study,10 researchers measured muscle hypertrophy following a 10-week exercise routine in which subjects performed one set of exercises lifting either heavy weights (80 percent full effort), or light weights (30 percent full effort) until they were fatigued. (Usually, subjects lifting weights at 30 percent full effort fatigue after 20-25 repetitions.) Surprisingly, while both protocols increased muscle strength and volume, only the light weights resulted in a significant increase in the number of mitochondrial proteins associated with accelerated repair and remodeling. (Figure 2)
Although the exact mechanism is unclear, it is theorized that the higher number of repetitions produces a greater increase in intramuscular pressure, essentially squeezing blood out of the muscle. The reduced blood flow decreases oxygen levels, causing a shift in muscle recruitment from just a few slow-twitch muscle fibers (which are dependent upon oxygen) to a much larger number of fast-twitch muscle fibers (which can function in an oxygen-free environment).
The more fast-twitch muscle fibers recruited with each set, the more specialized cells called satellite cells work to stimulate remodeling. Apparently, long rests between sets allow for the restoration of blood flow, which restores circulation and allows the body to go back to using just a few slow-twitch muscle fibers.8
5 Exercises for Maintaining Muscle Mass: The Sarcopenia Workout
Figure 3 reviews five simple exercises to maintain muscle mass in nearly every muscle of the body. (A video of the exercises is available at HumanLocomotion.org.) This routine, which can be performed at home with minimal equipment, takes about 15 minutes to complete and should be repeated at least twice a week.
Because the body adapts to specific exercise protocols, vary sets and repetitions on 12-week cycles. Some of the sets should be performed quickly and some slowly. The most important factor is to begin strength training early in life because it is not possible to increase the total number of muscle fibers in the body; it is only possible to maintain existing muscle fibers.
References
When sports chiropractors first appeared at the Olympic Games in the 1980s, it was alongside individual athletes who had experienced the benefits of chiropractic care in their training and recovery processes at home. Fast forward to Paris 2024, where chiropractic care was available in the polyclinic for all athletes, and the attitude has now evolved to recognize that “every athlete deserves access to sports chiropractic."
It is estimated that 61% of patients with CTS avoid taking surgical options due to postoperative complications and costly surgical procedures. Chiropractic care offers a comprehensive and effective treatment for carpal tunnel syndrome, addressing the condition from multiple angles. Recent studies also have unveiled a game-changing adjunct to chiropractic treatments for CTS: nerve flossing.
Some doctors thrive in a personality-based clinic and have a loyal following no matter what services or equipment they offer, but for most chiropractic offices who are trying to grow and expand, new equipment purchases help us stay relevant and continue to service our client base in the best, most up-to-date manner possible. So, regarding equipment purchasing: should you lease, get a bank loan, or pay cash?
