Effects of Kettlebell Swing Style and Mass on Female Hip Joint Kinetics.

Background: Kettlebell (KB) swing exercises, whether performed using shoulder height (SHS) or overhead (OHS) swing variations in therapeutic or strength and conditioning settings, are posterior chain dominant exercises that require hip extension contributions when performed correctly.

Purpose/ hypothesis: The primary purpose of this study was to evaluate the effect of swing style (SHS, OHS) and KB mass on hip extension kinematics and kinetics in young adult females. A secondary purpose was to determine the effects of swing style and KB mass on the forces applied to the total body center of mass and KB. It was hypothesized that velocity, power, and work would be greater for the OHS compared to the SHS, as well as for the heavier compared to the lighter KB's.

Study design: Crossover study design.

Methods: Fifteen physically active females performed 15 swings under four conditions, SHS/12kg, SHS/16kg, OHS/12kg, and OHS/16kg, while three-dimensional dominant limb foot, shank, thigh, pelvis, and KB kinematic and ground reaction force (GRF) data were collected.

Results: KB distance (95%CIDiff: 17.5-25.1 %BH), time (95%CIDiff: 0.067-0.023 s), and peak velocity (95%CIDiff: 0.56-0.74 m‧s-1) were significantly greater during the OHS (p<0.05). During OHS, significantly greater hip joint peak power (95%CIDiff: 1.6-4.1 W‧kg-1), work (95%CIDiff: 0.104-0.527), peak velocity (95%CIDiff: 7.6-40.5 °‧s-1) occurred compared to SHS, although the time and hip angular position of peak velocity and peak power were not statistically different between styles.

Conclusions: These results may influence choices of KB progressions, suggesting that one may first consider changes in KB mass prior to changing from the SHS style to the OHS style.

Level of evidence: Level 3.