Need motivation to get going on a strength training workout? This should help: New research out of the University of Michigan indicates people with weak muscles don't live as long as their stronger counterparts. The full report, published in the Journal of Gerontology: Medical Sciences, looked at more than 8,000 men and women 65 and older, measuring their grip strength and risk for "premature mortality." That term alone might be enough to make a person join the gym. Here's one local option for supervised weightlifting, suitable for all levels.

What it is: Barbell strength at Life Time, a group fitness class that gives a full-body workout. (Similar classes are available at the YMCA and other gyms.)

What's it like: I arrived early for the 8:15 a.m. class and set up a bench, added warmup weights to a barbell and stacked heavier weights nearby to use for lower-body exercises. There were about 25 people in the class, most regulars, ranging in age from 40- to 60-something. My nearest neighbor said she'd been taking the class at her doctor's recommendation, to combat osteoporosis.

The instructor, Todd Trepanier, cued the music and led us through a warmup with the barbell that covered upper and lower body, teaching us the right form for squats, arm curls and overhead presses. It felt easy, with 2.5-pound weights on the barbell. Then things took a turn for the challenging as he upped the pace, the volume of the music and the pounds on the bar.

We used heavier weights for what Todd said was six minutes of squats, but it sure felt like 10. We did full range of motion, half-range and then a long series of killer pulses, a pattern we'd repeat on most of the exercises. Then we dropped the weight on our bars by a third, and quickly moved to the bench for chest presses.

Next, for reverse fly, we dropped the barbell and used free weights. Then it was back to the bench for dips to target our triceps. On we moved through bicep curls, calf raises and lunges, then shoulder and ab exercises, and finally a cool-down/stretch.

Each series of exercises targeting a group of muscles lasted at least a couple of minutes — enough time to learn unfamiliar moves and repeat them to get a feel for proper form. After the squats, I decided to keep the weight on my bar on the low end so that I could move in a controlled way while I learned. Even so, I felt the workout the next day.

Who it's for: This class works for beginners on up, because you can modify, adding lots of weight or no weight to the barbell. While the pace is brisk, Trepanier emphasized form over speed, reminding class members to stop if their form was falling off. Maybe the biggest challenge is changing the weights quickly and knowing how much to add.

Would I go back? Absolutely. The class was welcoming and friendly, the instructor was seasoned and the workout felt complete. While people seemed to be in very good shape, I didn't get a vibe that anyone was judging anyone else.

What to know before you begin: Show up early to get your equipment lined up. I had the bench, mat, a towel, a barbell and three stacks of weights. Also, let the teacher know you're new. I caught Trepanier looking my way throughout the class to check on my movements, which reassured me. Plus, he offered encouragement without making me feel singled out.

Pro tip: Try before you buy. Life Time offers a free pass to adults to check out the club. Go to lifetime.life/join/pass.html to request one.