As long as you can attain a comfortable seated position on the rower, you can vary the intensity of the workout to suit your desired exertion level. Truly, you can just cruise quite easily or you can launch yourself into anaerobic coma. The rower provides a "whole body" workout, with most of the thrust provided by your posterior chain of muscles. The posterior chain, comprised of hamstrings, gluteal group, and lower back, is responsible for the majority of power production in virtually all athletic endeavors. It also contributes to stability of the spine and resultant improvement in balance.
Why don't you try the rower out at the health club and see what you think? If you don't like the rower, I can help you devise alternatives to develop the same strengths via different methods.
One of the most relevant concerns as we age is the possibility of slip/fall injuries. As you know, the fall/broken hip event is responsible for premature senescence and disability in us older folks. For many, the broken hip leads to early death, with 5 year survival rates bearing this out. One major reason for broken hips is the inability to "catch oneself" after tripping/slipping by throwing a foot out to act as a "post". Lack of sufficient leg strength (due to inactivity) leads to insufficient plyometric capacity (springiness), meaning that one cannot produce enough power to stop the fall, even when the leg is put into proper position to catch you. Poor spinal stability and "core strength" deteriorate one's balance and slow the reaction that could keep you from falling, so you can't get your foot out there to catch you in the first place.
I'm perseverating about this aspect of fitness because many of us have no desire to be "athletes". Since my personal fitness requirements are quite high (fighting full-contact with 20+ year old combatives guys), I don't want to come off as a maniac who wants everyone to sacrifice precious time to achieve levels of fitness beyond their needs. In the OR, I see daily the results of inactive lifestyles and poor self-maintenance. A simple, intelligent plan can enhance quality of life with minimal time expenditure. It truly depends upon proper choice of activity to fit one's lifestyle.
I'll be happy to address any fitness issues and help in any way I can.
Lee
Lee - A couple of comments in regard to your post.
1. Rowing is a good though advanced exercise --and not everyone can do it (eg. those with back or flexibility issues). Power production should come from the hips, not the lumbar spine. The lumbar spine is built for stability and weight bearing. The transverse processes prevent vertebral rotation and trying to rotate in the lower back leads to sheer stress on the IVD and SI joint (not good things).
Good core training and I suggest Stuart McGill's Ultimate Back Performance and Fitness or Gray Cook's The Athletic Body in Balance for reference, starts with grooving motor patterns, working endurance, later strength and then one can do more dynamic efforts such as Olympic Weightlifting or power lifting.
2. Many incident of falling esp. in women is due to the bone eg femoral neck breaking first, not the fall braking the bone. There are studies out there that show actually that weakness in the calves actually can contribute to falls. Calves are a postural muscle meant to keep us standing erect.
And as I talk about in my seminars, core training is the most overused and least understood term out there maybe next to functional training. Core actually begins with the nervous system firing and proper shoulder and hip mobility. To wit, the brain is not stupid and when someone wants to move their body, the brain will devise a movement pattern to accomplish the task. So if someone has limited shoulder or hip mobility, such as say in a golfer or tennis player, the brain will sacrifice something to achieve the movement; in this case, the brain will sacrifice core stability (which we'll define as a dynamic 3D structure, with top and bottom, sides, front and back; core stability will also depend upon breathing patterns). Ergo, then the golfer wonders why his/her lower back hurts. They can do as much rehab core as possible--they will continue to suffer from back pain til they fix the real problem. Or as we say, the problem is not at the joint itself, it's at the joints above or below.
Now I'll also argue that rowing is not going to improve strength; it will improve cardiovascular performance. That's because aerobic endurance activity activates the AMPK pathways that shuts down protein synthesis to conserve energy; resistance training (I'm not saying weightlifting since it's a different term unfortunately used interchangably) activates cellular pathways such as mTor (mammalian target of rapamycin) and it activates protein synthesis through integration of different cellular stimuli such as stress, leucine, steroids, HGH and others to be discovered. So if one want's to build leg strength, it's better to do strength training.
In regards to building bone strength, it has been shown that plyometrics can help women's bones (remember that plyos are a subset of explosive training --and it's explosive training that works as a whole). But one can't just jump in and do plyometrics. One needs a significant training base since plyos really stress the connective tissue. And many older people can't do that.
Finally any good cardio conditioning workouts should be periodized just like resistance training. The simplest way is Med-light-hard-light-med-light....to let the body rest and recuperate. Otherwise the body will break down. Then one needs to base the training program around one's HR derived from the Karvonian forumula (or heart rate reserve). By working thru different HRs, one is striving to build up the different proteins that contribute to metabolism of fats, carbs and protein. So everyone should invest in a HR monitor such as that sold by Polar and say set up assuming they are in good condition with no injuries something like light = 60-65%; medium: ~70%; hard: 80-85% (but one can't keep this stress level up for long periods of time so this is usually done with interval type training--that interestingly because of the EPOC effect, actually leads to burning fat after one leave's the gym).
As far as equipment choices go, much will have to do with age, injuries, etc. The bike is good for someone with say back, knee or foot injuries--but walking on the treadmill (at iso-heart rates) will burn more calories than the equivalent time on the bike. The elliptical is like the bike, good esp. for those with injuries. Don't believe the calories burned readout here! It's about 65% of what's listed. The only cardio equipment whose calories burned readouts can be trusted is the treadmill. The treadmill is a good piece to have and multi-functional. One can walk (and retrograde too), run, and ajust inclines. Injuries will come into play here--and a treadmill for instance might not be the best choice for someone with herniated/bulging discs). The rower is good but again back injuries are contraindicated. One must be careful not to round the back and stress the lumbar spine. The rower is also good to focus on building the rhomboids and posture (in this case, endurance is targeting the type 1 fibers, responsible for joint stability and endurance-and responding oppositely of type 2/strength fibers). I like if there's no contraindications, the step mill (escalator) or versa climber. Both are really tough workouts! I don't advise the stairmaster since I really feel it's too impactful for the back, hips and knees-esp for women!
Then there are many variants on ellipticals, etc. Some ellipticals such as Lifefitness is intended to emulate running and as such has a longer stride length than does a precor elliptical. Then there are ellipticals that function more like treadmills.
BTW, if money is no object, the two best treadmills out there are the 10 K or so depending upon options Woodways (great for runners and athletes and one's body) and Nordic Trac (great for athletes too and can be adjusted for -5 to +50 degrees eg. running downhill to hiking a mountain.
If anyone has any questions, feel free to ask.