Q: Are there any muscles or muscle groups that older lifters need to pay extra or special attention to?
This is great question, and no, it's not an easy one to answer. The most accurate and useful answer will vary from individual to individual, depending on their lifestyle and injury history, of course. For example, if your posture is terrible and you're in constant back pain, well, that's the most important thing to fix! But generally, I believe leg musculature should be prioritized above all else.
I have a few different reasons for this opinion. Before you run for the squat rack, check them out.
Self-Sufficiency
First and perhaps foremost, healthy and strong legs are what allow you to be ambulatory and, hence, self-sufficient. While a bum shoulder isn't any fun either, a bad hip or knee has much more impact on your overall quality of life. By developing and maintaining good glute, hamstring, and quadriceps strength, you're much more likely to keep these important joints healthy and well-functioning.
Speaking of ambulation, a strong lower body helps you safely navigate your environment. A few months ago, I was walking into the grocery store wearing flip flops, and it had been raining earlier, so my feet were wet. As I approached the slick tile flooring inside, I remember thinking that I should be careful, but despite that awareness, I slipped and fell anyway.
I was fine as it turned out—more embarrassed than anything else—but it was the first time I'd fallen in years, and it struck me as a much more significant event than times I had fallen in my 20s. Bear in mind, I'm a guy who was in the best shape of my life at 55, lifts regularly, and has even competed in powerlifting in the not-distant past. But a single fall definitely got my attention and made me think about what could have happened.
I was grateful for being strong enough to minimize the effects of the fall, but also aware that a similar fall when I'm 70 or 80 would potentially be a serious event. The stronger your legs are, the more steady you'll be on your feet in challenging circumstances, and even if you do slip and fall, you'll be more likely to emerge unscathed.
Leg Strength Provides "Margin"
Here's an analogy I often share with clients: Think about rising up from a chair, which is essentially a bodyweight squat. Next, imagine two individuals doing that with loaded barbells on their back, which is basically a box squat. One can barely squat 350 pounds while the other can barely squat 50. Obviously, the 50-pound squatter only has 50 pounds of margin between his current capacity and being unable to rise from a chair while the 350-pound squatter, is much further away from being incapacitated.
To be clear, this isn't necessarily a reason to chase limit strength forever, though. It's not necessarily better to become a 700-pound squatter, because the orthopedic costs of getting that strong would likely outweigh the benefits. And when you have that many pounds on your back, you're only a split second from being incapacitated at any particular time.
Strong Legs Can Make Everything Stronger
The leg muscles—particularly the calves, believe it or not—are sometimes called your body's "second heart" because they help to return circulating blood back to the heart. The stronger and more muscular your legs are, the better they can serve in this role.
If done correctly, strength training your legs will improve not only strength and size, but also mobility, all of which translates to healthier knees, hips, and lumbar spine. As an example, properly-performed RDL's can play a significant role in lengthening the hamstrings, which helps to bulletproof your lower back, because you'll be able to perform squat, hinge, and lunge patterns without flexing your lumbar spine. Similarly, performing full-range squats promotes improved ankle range of motion, and when the ankles move freely, the knees, hips, and spine are spared compensatory adjustments.
Leg Training Builds Muscle and Burns Calories
Given their (at least potentially) significant size, the leg muscles have a strong contribution to overall metabolic rate, and by extension, your body composition. Leg-powered activities also tend to burn the most calories, and have the potential to send the most powerful anabolic signals throughout your body.
Put another way, some curls may help you add a bit of muscle to your arms. But squats along with curls will set you up for not only bigger arms, but a leaner, more muscular physique from head to toe. This is a major reason why my Bodybuilding.com BodyFit Elite program Total-Body Strong has leg training included in each of the three weekly workouts.
It's no coincidence that I like to put the leg work first thing in full-body workouts. It's the main course! You can see an example of what that style of training looks like in my article "This Is Full-Body Training Done Right."
Don't Forget You Have Choices
One final note about leg-training strategy, especially for older lifters: If you have good orthopedic health and relatively normal proportions, you'll have the benefit of at least two different "ground management" strategies—hinging from the hips, and squatting.
On the other hand, if your knees are shot, you'll get more reward and less risk from hip hinging, so embrace that, and get good at it. Bad hips or back? Front-loaded squats and lunges may be more your speed than deadlifts or barbell back squats. Having a full arsenal of movement substitutions, like my friend John Rusin offers up in his guide Unstoppable: The Ultimate Guide to Training Through Injury, is a no-brainer.
My big point here is, do what you can to improve your strength, mobility, and muscle mass, but within reason. If you have arthritic knees, sure, do your best to maintain your strength and mobility, but don't set a goal of squatting 400 pounds. Even if you manage to accomplish it, the risks are too great.
Similarly, if you have a herniated lumbar disk, ease up on those heavy deads, as much as I hate to be the bearer of bad news. Especially when you're older, smart training isn't only about improving. Sometimes it's also about damage control. When considering your training goals, think not only about the benefits, but also the costs.
Keep moving forward a little at a time, and just as importantly, look to minimize the amount of time you spend moving backward!