Do Kettlebells Improve Strength and Power?

Kettlebell training has experienced a resurgence of late. Going by the physical improvements the training can offer, is its popularity warranted? The answer is yes, according to a study published recently in the Journal of Strength & Conditioning Research (2012; 26 [8], 2228–33).

The scientists’ goal was to determine what effects the kettlebell swing had on maximal and explosive strength. They employed half-squat 1-repetition maximum and vertical jump height as assessment markers.

The study included 21 young men, aged 18–27, who were experienced at both the half-squat and the vertical jump. One group of men performed 12 minutes of exercises—12 rounds of 30-second exercise bouts alternating with 30-second rest periods—using a 12- or 16-kilogram kettlebell, depending on body weight. The other group performed at least 4 sets of 3 jump squats with varying loads (60% 1-RM to 0% 1-RM). Both groups trained twice per week.

At the end of the study, the two groups demonstrated similar improvements in maximal and explosive strength.

“The results of this study clearly demonstrate that 6 weeks of biweekly kettlebell training provides a stimulus that is sufficient to increase both maximum and explosive strength, offering a useful alternative to strength and conditioning professionals seeking variety for their athletes,” explained the study authors.

Want to help your clients stay safe during kettlebell swings? First, make sure you are educated in this type of training, says BJ Gaddour, CSCS, CEO of StreamFIT.com in Milwaukee. He suggests using the following exercises to prepare clients for swing training:

Hamstring stretch. Lack of hamstring flexibility will result in flexion of the lower back at the bottom of the swing pattern, putting the spine at great risk of injury. Gaddour’s favorite stretch for helping with swings is a progressive straight-leg hamstring stretch using a staircase. Start with the first step and keep working your way up the staircase until, ideally, you’re stretching your hamstring with more than 90 degrees of hip flexion, with no movement in the lumbar spine.

Hip hinge. With soft knees and heels loaded, hinge back at your hips as if trying to close a car door without squatting excessively. If you feel the movement in your thighs, you’re squatting too much.

Skier swing. In traditional kettlebell swings, you hold the bell(s) between the legs while adopting a wider foot stance. For skier swings, you hold the weights outside the thighs and stand with feet closer together. A closer stance makes it more difficult to squat, which forces you to hinge back more at the hips, cleaning up the form. You may want to start with lighter dumbbells before adding the pendulum effect created by the shape of the kettlebell.