Kettlebell training offers unique benefit to the core and spine, says a study from the Journal of Strength and Conditioning Research.
The authors set out to simply study the mechanics and muscle activation patterns of kettlebell training, since no previous studies existed. They studied the swing, snatch, and carry. They found that kettlebell swings and snatches use a whole host of core muscles. Starting at the bottom of the swing, muscle activation proceeded from the back to the abs, glutes, and legs. The kettlebell snatch activated the same muscles as the swing, just in greater magnitude—sometimes more than 50% greater for a kettlebell of the same weight!
Kettlebell carries at shoulder height were also studied. Participants carried a kettlebell either racked on the back of the arm or balanced upside down, with the bell above the handle. The authors found that carrying the kettlebell upside down forced more grip and core activation. The upside down carry undoubtedly turns the exercise into an active game of balance and motor control.
But perhaps the most interesting finding is that kettlebell training stresses the spine much differently than traditional barbell lifts like a deadlift or a squat. Shear forces on the spine during kettlebell swings and snatches act in the opposite direction from those of lifting a barbell. The authors suggest this may be beneficial to back health as part of a strength training program.
This doesn’t mean you can ignore safety when choosing kettlebell loads. Shear forces on the spine in any direction can injure if your body is not prepared for them. But this does indicate that kettlebell training may be more than just an accepted accessory to the barbell. Kettlebells may indeed be a necessary companion to the barbell in a proper strength program.