Kettlebells are most often viewed as a strength training tool, but they can also lead to significant gains in aerobic fitness, according to research published in the Journal of Strength & Conditioning Research.
In a small study, female soccer players who did an intense kettlebell workout three times a week for four weeks in addition to their usual training increased their VO2 max, a measure of aerobic fitness, by 6 per cent, while teammates who added a regular circuit training workout to their program saw no such improvement.
The kettlebell workout the women did consisted of 15 seconds of kettlebell snatches followed by 15 seconds of rest, repeated continuosly for 20 minutes. Kettlebell snatches (demonstrated in the video below) are done by bringing the kettlebell from between the legs to above the head with one arm. In the study, the soccer players alternated arms for each 15-second work bout, and were told to do the snatches as quickly as possible.
The circuit training workout consisted of five sets of a series of exercises such as ball squats, push-ups and a sprint performed in two minutes, with two minutes of rest between the set. Therefore, as with the kettlebell workout, the total work time was 10 minutes.
The kettlebell group’s jump in aerobic fitness didn’t occur because they were otherwise inactive. As the researchers wrote, “Athletes performed a resistance session for approximately 1 hour, then the [20-minute kettlebell or circuit training workout] followed by aerobic/anaerobic cardiovascular training. The only difference in the training program between groups was the [kettlebell or circuit training workout].”
For their workouts, the women used 12-kilogram kettlebells, which were approximately 18 per cent of their body weight.
The researchers said that their finding has potential relevance beyond the immediate scope of their study.
“This protocol may also be used during injury rehabilitation,” they wrote. “Athletes who have sustained a lower extremity injury that warrants little to no impact can perform this protocol as an alternative to maintain aerobic conditioning. The kettlebell snatch is a low-impact, dynamic exercise that provides sufficient resistance for muscle strengthening, in addition to enhancing aerobic capacity.”
The video below demonstrates how to safely do a kettlebell snatch.