Even when you train and eat protein, you will eventually lose some muscle. And muscle loss is the primary contributor to loss of function with age:
The average is 3-8% of muscle lost per decade after 30, and that loss accelerates after 60. The implications of this cannot be overstated, as it is a causal contributor to loss of bone density, loss of insulin sensitivity (aka - becoming more prediabetic/diabetic), loss of stature, loss of balance, loss of most fitness and health markers.
Weight loss doesn’t help. The average muscle and healthy tissue-loss during weight loss is 20%:
And it is not regained with weight gain. A person who has lost about 10lbs a few dozen times over the years has lost 2lbs of muscle, cartilage, and bone density multiplied by the same number of weight loss bouts. There’s a good chance there are 30 fewer pounds of muscle on that person, even if at the same body weight as before. There is less cartilage integrity in joints if she never lifted weights. There is less bone density.
Thus, you can see that people who yo-yo in weight but don’t do resistance exercise and sufficient protein intake simply get weaker and less mobile as they age. It’s not simply that your risks of fall increase as you lose muscle, it’s that the degree of damage possible FROM THE FALL increases with loss of muscle:
I don’t need to enumerate the many signs of severe lean tissue loss. Inability to stand on one foot while you put a sock on the other is a decent measure. Getting on and off the floor without the use of hands is another. Handstands, pushups, pull-ups, cartwheels, full bridge, vertical jump, sprint speed, single leg squat, etc. There are many. Most “bad joints” are actually insufficient muscle. And even when the joints are indeed critically failing, you better believe that having piles of lean tissue around them makes the symptoms 1000% better. In 20 years of professional training and coaching, I have observed many people with “bad joints” get to performances they believed impossible simply by getting stronger and regaining some muscle.
And this isn’t a plague of age. Young people are more susceptible to dislocations, collapse, and injury when they are detrained and have muscle weakness:
There are a number of studies showing that lean tissue loss is a predictor of mortality:
To be clear, how much loss of strength predicts IF you recover from anything, which includes respiratory infections, just fyi. After a certain degree of strength loss, people simply die. Strength loss is an independent predictor of mortality:
Weakness literally kills people.
Perhaps more perplexing to people, muscle tightness and perception of inflexibility IS weakness. Tight hamstrings are weak. Tight backs have weak abs and weak hip flexors and usually weak hamstrings to boot. Tight necks are incredibly weak necks and shoulders. Aching and falling arches are weak feet and ankles. You get the idea.
Muscle is next-to impossible to gain or regain or even retain as a full-grown adult. That is, unless you consistently train to get stronger across years, and consistently eat sufficient protein intake for years.
But the selection of exercise is also critical. Walking isn’t a muscle builder because it occurs on a vertical skeletal alignment. That does not train the capacity of the body when the thigh is horizontal. A bicep curl is not going to help a person to stand on one leg and pull the opposite knee into her armpit. It’s not that these are no-value exercises. They are just low value with regard to high function of the body. Avoidance of contacting muscles in the shoulder WILL worsen neck and shoulder problems. Strong necks and shoulders simply don’t ache. They don’t degenerate. They aren’t tricky. As such, the selection of exercises must be some sort of approximation of the intended physical capability which the person wants to regain AND a direct confrontation of where that person is already measurably weak.
This is a more difficult confrontation than one might expect. People may trend toward a longer walk or a longer bout of cardio, reasoning that the longer duration or distance is an increase in physical fitness. People may love their arm circuit training or Tabata arm series. But these will do absolutely zip nada for genuine fitness. Spending even more time in an activity which cannot confer muscular development will not magically confer muscular development, no matter how long that person spends on the activity.
Cardio doesn’t help much. It is catabolic, meaning it breaks down tissue. The intensity of muscular contraction is very low. The skeletal angles are such that the muscles never must produce much force. Ergo, it won’t shield from major muscle loss AND it will often accelerate it, UNLESS the person is measurably getting stronger in lifts week over week.
And without going too far into the science, suffice it to say that the person must feel the intended muscle he or she is trying to develop AND generate such tension in it that there is a serious question about whether the rep can be completed at the end of a set. That, and pretty much only that, is going to spur on muscle building.
If you used to be able to squat all the way down but now can barely bend your knees, you lost far too much muscle already. If you used to do handstands but now can barely reach your hands overhead, you lost far too much muscle already. If you used to not have stiff muscles but now they’re tight all the time, you lost too much muscle and strength.
Long story short: if you have not intentionally been training to gain muscle or get more athletic, you have lost a lot of muscle and healthy tissue.
And if you want to turn that around, it doesn’t actually need to be too involved. What are the physical abilities you’d like to build, rebuild, or retain? Work strengthening exercises specifically toward those. That’s it. Really.
And when you work them, it is critical that you create enough tension in the muscle to communicate to the body that it must adapt. What that means is that you should not pick any ol’ rep range and then stop AT that arbitrary point. For example, if you pick up a weight which you can confidently perform for an exercise 10 reps, your objective is to commit to 11-20 controlled quality reps which end at zero velocity because your muscle can no longer generate any speed of the exercise. It absolutely does not matter what you read or heard about rep ranges. It doesn’t matter what you saw in a magazine or heard in a group ex class. Your muscle fibers only know if they’ve been taken near their performative limit. That. Is. It. If you move the weight quickly and with ease and end the set before your physiology has ground to a velocity of zero while trying earnestly to complete a repetition which it cannot, then you simply haven’t trained. You have not strengthened. You have not communicated to the body to gain, regain, or retain muscle.
“Failure” isn’t really even the right term. There are too many common misconceptions about this concept. People will use momentum and kipping and cheating to nab another rep. That’s not it. Really, it’s just a matter of placing effort into the exercise until your will cannot make the muscles move the exercise movement one more millimeter.
That’s the stimulus.
The environment which will respond to that stimulus is one of sufficiency. Vitamins. Minerals. Water. Sleep. Rest. Protein. A whole lotta protein. If you can’t imagine eating 1 or more grams of protein per pound of body weight, at the very least hit .5. If you weight 100lbs, the absolute low-end bottom of healthy intake would be a half pound of meat or equivalent protein source daily. For obvious results, double or triple this.
And perhaps one can see why even really well-intentioned and hard-working exercisers and health enthusiasts tend to fail completely at making significant and obvious physical progress. Lots of light weights shy of high effort won’t do much. Lots of cardio won’t do much. Lots of green veggies won’t do much.
It’s not that any of those things are bad. It’s just that none of them yield a high ROI for the most needed facets of fitness. Intense weight lifting, progressively and consistently performed, with a diet rich in protein, and sufficient sleep and stress management will outperform pretty much any other trendy programming in existence.
Otherwise, you’re going to lose muscle.