It’s well-known that compound, whole body movements typical of kettlebell exercises are more functional to machines that isolate muscles for improving muscle tone, body composition, and strength. Further, kettlebells create an effective full body workout as they combine the benefits of strength training and cardiovascular exercise.
Most of our instructors and trainers were at the annual Canfitpro Fitness Convention in Toronto this past weekend and enjoyed a workshop we took that focused on using lighter weight kettlebells and combined them in both traditional and non-traditional ways for a fun, total body, calorie-scorching, muscle defining workout! We liked it so much in fact, we’ll be purchasing more kettlebells so we can use them in group classes this way too. As much as we like to offer large equipment and free weights, we also love our small equipment like balls, bands and now kettlebells and lots of them so they can be used in our classes not just in the gym!
In the fitness business, often hype about new training techniques can outpace objective evidence about how well they actually work. That was certainly true for kettlebells, the cannonball-with-a-handle training tool that started showing up on lists of fitness trends about three years ago.
But, eventually, the evidence catches up. A pair of studies published last month in the Journal of Strength and Conditioning Research take a hard look at how well kettlebells fulfill their promise of better strength, power and aerobic fitness.
The current enthusiasm for kettlebells, whose murky origins can be traced back to 18th-century Russia, stems in part from their simplicity. A few basic movements with a single piece of equipment can raise heart rate and recruit muscles throughout the body, in contrast to traditional weight training, which uses specific exercises to isolate individual muscles.
One of the challenges in evaluating the effectiveness of kettlebells is figuring out what to compare them to. For strength and power, exercise physiologist Jared Coburn and his colleagues at California State University in Fullerton chose three standard kettlebell moves – the kettlebell swing, accelerated swing and goblet squat – and matched them to three traditional weight-lifting exercises: the high dead lift, power clean and back squat.
The researchers randomly assigned 30 volunteers to follow identical programs using either kettlebells or barbells for six weeks, then measured their strength and power. As expected, both groups improved. The gains were similar in measures of power, like vertical jump, but for strength the gains were bigger with barbells. In the maximal back squat, for example, the barbell group increased by 13.6 percent, while the kettlebell group increase by only 4.5 percent.
One explanation for the difference is that kettlebell movements emphasize speed and explosiveness, but are less suited to dealing with very heavy weights, Dr. Coburn says: “My advice would be to incorporate them into a training program alongside more traditional methods, not as a permanent replacement.”
At the other end of the fitness spectrum, researchers at Truman State University in Missouri pitted a 10-minute kettlebell swing routine (35 seconds of swinging alternating with 25 seconds of rest) against a 10-minute treadmill run. In order to get a fair comparison, they had their volunteers repeatedly estimate their perceived exertion during the kettlebell routine on a standard numerical scale from 6 to 20. Next, they continuously adjusted the treadmill speed so that the perceived effort of the two workouts stayed the same.
On the surface, the results were clear: The treadmill workout burned more calories and consumed more oxygen than the kettlebells, by 25 to 39 per cent. Still, the kettlebell routine maintained heart rates up above 85 per cent of maximum, enough to produce gains in cardiovascular fitness. And there was an interesting wrinkle: To keep the effort levels matched, the subjects had to keep adjusting the speed of the treadmill to go faster and faster – a pattern that, in practice, most gym-goers don’t follow.
The verdict on the aerobic benefits of kettlebells, then, is very similar to the verdict on their strength-training benefits. In an appropriately matched head-to-head contest, kettlebells don’t quite stack up in either category, but are nonetheless decent in both categories. That means you can tailor your workout to favour one extreme or the other, or choose a middle ground.
“If it’s a heavier kettlebell that’s lifted only a few times, it’s probably a strength workout,” says Jerry Mayhew, the senior author of the Truman State study. “If it’s a lighter kettlebell that’s lifted in rhythm for an extended time, like three to five minutes, it’s probably more of a cardiovascular workout.”
In other words, it’s not the fitness equipment that matters; it’s what you do with it.
Safe kettlebell usage
Kettlebells put less compression but more lateral force on your vertebrae compared to conventional barbells, according to research by the University of Waterloo’s Stuart McGill. As a result, proper form is important – master the motions with no weight before picking up a kettlebell. Dr. McGill recommends starting with the “shortstop squat” to practice keeping the spine in a neutral position: hands on knees, bending with the hips and looking straight ahead