The aim of this study was to establish the effect that kettlebell swing (KB) training had on measures of maximum (half squat-HS-1 repetition maximum [1RM]) and explosive (vertical jump height-VJH) strength. To put these effects into context, they were compared with the effects of jump squat power training (JS-known to improve 1RM and VJH). Twenty-one healthy men (age = 18-27 years, body mass = 72.58 ± 12.87 kg) who could perform a proficient HS were tested for their HS 1RM and VJH pre- and post-training. Subjects were randomly assigned to either a KB or JS training group after HS 1RM testing and trained twice a week. The KB group performed 12-minute bouts of KB exercise (12 rounds of 30-second exercise, 30-second rest with 12 kg if <70 kg or 16 kg if >70 kg). The JS group performed at least 4 sets of 3 JS with the load that maximized peak power-Training volume was altered to accommodate different training loads and ranged from 4 sets of 3 with the heaviest load (60% 1RM) to 8 sets of 6 with the lightest load (0% 1RM). Maximum strength improved by 9.8% (HS 1RM: 165-181% body mass, p < 0.001) after the training intervention, and post hoc analysis revealed that there was no significant difference between the effect of KB and JS training (p = 0.56). Explosive strength improved by 19.8% (VJH: 20.6-24.3 cm) after the training intervention, and post hoc analysis revealed that the type of training did not significantly affect this either (p = 0.38). The results of this study clearly demonstrate that 6 weeks of biweekly KB 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.

The aims of this study were to establish mechanical demands of kettlebell swing exercise and provide context by comparing them to mechanical demands of back squat and jump squat exercise. Sixteen men performed 2 sets of 10 swings with 16, 24, and 32 kg, 2 back squats with 20, 40, 60, and 80% 1-repetition maximum (1RM), and 2 jump squats with 0, 20, 40, and 60% 1RM. Sagittal plane motion and ground reaction forces (GRFs) were recorded during swing performance, and GRFs were recorded during back and jump squat performances. Net impulse, and peak and mean propulsion phase force and power applied to the center of mass (CM) were obtained from GRF data and kettlebell displacement and velocity from motion data. The results of repeated measures analysis of variance showed that all swing CM measures were maximized during the 32-kg condition but that velocity of the kettlebell was maximized during the 16-kg condition; displacement was consistent across different loads. Peak and mean force tended to be greater during back and jump squat performances, but swing peak and mean power were greater than back squat power and largely comparable with jump squat power. However, the highest net impulse was recorded during swing exercise with 32 kg (276.1 ± 45.3 N·s vs. 60% 1RM back squat: 182.8 ± 43.1 N·s, and 40% jump squat: 231.3 ± 47.1 N·s). These findings indicate a large mechanical demand during swing exercise that could make swing exercise a useful addition to strength and conditioning programs that aim to develop the ability to rapidly apply force.

The aim of this study was to compare mechanical output from kettlebell snatch and 2-handed kettlebell swing exercise. Twenty-two men performed 3 sets of 8 kettlebell snatch and 2-handed swing exercise with a 24 kg kettlebell on a force platform. Vertical and horizontal net impulse, mean force, displacement, the magnitude and rate of work vertical CM displacement was significantly larger than horizontal CM displacement, regardless of exercise (20±3 vs. 7±1 cm, p<0.0001); 2) the magnitude (253±73 vs. 3±1 J, p<0.0001) and rate of work (714±288 vs. 11±4 W, p<0.0001) performed to vertically displace the CM was larger than the horizontal equivalent in both exercises, and the magnitude (5±2 vs. 1±1 J, p<0.0001) and rate of work (18±7 vs. 4±3 W, p<0.0001) performed to horizontally displace the CM during 2-handed swing exercise was significantly larger than the kettlebell snatch equivalent; 3) this was underpinned by the magnitude of horizontal impulse (29±7 vs. 18±7 N.s, p<0.0001) and the impulse ratio (23 vs. 14%, p<0.0001). These findings reveal that, apart from the greater emphasis 2-handed swing exercise places on horizontal mechanical output, the mechanical output of the two exercises is similar. Research shows that 2-handed swing exercise improves maximum and explosive strength. These results suggest that strength and conditioning coaches should consider using kettlebell snatch and 2-handed swing exercise interchangeably for the ballistic component of athlete strength and conditioning programs.

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The aim of this study was to compare measures of power output applied to the center of mass of the barbell and body system (CM) obtained by multiplying ground reaction force (GRF) by (a) the velocity of the barbell; (b) the velocity of the CM derived from three-dimensional (3D) whole-body motion analysis, and (c) the velocity of the CM derived from GRF during lower-body resistance exercise. Ten resistance-trained men performed 3 maximal-effort single back squats with 60% 1 repetition maximum while GRF and whole-body motion were captured using synchronized Kistler force platforms and a Vicon Motus motion analysis system. Repeated measures analysis of variance of time-normalized kinematic and kinetic data obtained using the different methods showed that the barbell was displaced 13.4% (p < 0.05) more than the CM, the velocity of the barbell was 16.1% (p < 0.05) greater than the velocity of the CM, and power applied to the CM obtained by multiplying GRF by the velocity of the barbell was 18.7% (p < 0.05) greater than power applied to the CM obtained by multiplying the force applied to the CM by its resultant velocity. Further, the velocity of the barbell was significantly greater than the velocity of the trunk, upper leg, lower leg, and foot (p < 0.05), indicating that a failure to consider the kinematics of body segments during lower-body resistance exercise can lead to a significant overestimation of power applied to the CM. Strength and conditioning coaches and investigators are urged to obtain measures of power from the force applied to and the velocity of either the barbell (using inverse dynamics) or CM (GRF or 3D motion analysis). Failure to apply these suggestions could result in continued overestimation of CM power, compromising methodological integrity.

This study compared differences between ballistic jump squat (B) and nonballistic back squat (NB) force, velocity, power, and relative acceleration duration, and the effect that the method used to identify the positive lifting phase had on these parameters. Ground reaction force and barbell kinematics were recorded from 30 resistance trained men during B and NB performance with 45% 1RM. Force, velocity, and power was averaged over positive lifting phases identified using the traditional peak barbell displacement (PD) and positive impulse method. No significant differences were found between B and NB mean force, and mean power, but B mean velocity was 14% greater than the NB equivalent. Positive impulse mean force was 24% greater than PD mean force, and B relative acceleration duration was 8.6% greater than the NB equivalent when PD was used to identify the end of the positive lifting phase. These results challenge common perceptions of B superiority for power development.

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The aim of this study was to examine the effects of barbell load on countermovement vertical jump (CMJ) power and net impulse within a theoretically valid framework, cognisant of the underpinning force, temporal, and spatial components. A total of 24 resistance-trained rugby union athletes (average ± SD: age: 23.1 ± 3.4 years; height: 1.83 ± 0.05 m; body mass (BM): 91.3 ± 10.5 kg) performed maximal CMJ under 5 experimental conditions in a randomised, counterbalanced order: unloaded, and with additional loads of 25%, 50%, 75%, and 100% of BM. Peak power and average power were maximised during the unloaded condition, both decreasing significantly (P < 0.05) as load increased. Net impulse was maximised with 75% of BM, which was significantly greater (P < 0.05) than the unloaded and 100% of BM conditions. Net mean force and mean velocity were maximised during the unloaded condition and decreased significantly (P < 0.05) as load increased, whereas phase duration increased significantly (P < 0.05) as load increased. As such, the interaction between barbell load and the underpinning force, time, and displacement components should be considered by strength and conditioning coaches when prescribing barbell loads.