Mike A. Lauder

Kettlebell swing training improves maximal and explosive strength

Abstract Lake, JP and Lauder, MA. Kettlebell swing training improves maximal and explosive strength. J Strength Cond Res 26(8): 2228–2233, 2012—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.

Improved accuracy and reliability of sweepback angle, pitch angle and hand velocity calculations in swimming

The estimation of forces in swimming using the quasi-static approach (Schleihauf, In: J. Terauds, J.P. Clarys (Eds.), Swimming III, International Series on Sports Sciences. Vol. 8, University Park Press, Baltimore, 1979, 70-109) has been popular in recent years as propulsion is an important determinant of performance. The aim of this study was to establish the accuracy and reliability of current and newly proposed procedures for the reconstruction of hand velocity, sweepback angle and pitch angle from underwater three-dimensional video analysis. A full-scale mechanical arm capable of simulating a controlled and highly repeatable underwater phase of the front-crawl stroke was filmed for a set of five trials. A seven-point model of the arm and hand was then digitised at 25 Hz. Hand velocity, sweepback angle and pitch angle were calculated using the procedures of Schleihauf (1979), Berger et al. J. Biomech. 28 (1995) 125-133 and a newly proposed procedure (Lauder). Statistical comparisons were made between procedures to establish their relative accuracy and reliability throughout the stroke. The mean absolute error in measurement of hand velocity between points on the hand was very small (+/- 0.04 and +/- 0.06 m s(-1) in the x and z directions, respectively). The mean errors in sweepback angle and pitch angle were, respectively, 9.3 degrees and 7.6 degrees (Berger), 10.1 degrees and 8.1 degrees (Schleihauf and 10.7 degrees and 7.0 degrees (Lauder). Agreement between procedures showed the standard error between Schleihauf and Lauder to be the least (Schleihauf and Lauder, 0.4 degrees; Berger and Schleihauf, 1.3 degrees; Berger and Lauder; 1.6 degrees). The use of four points in the reconstruction of the orientation of the hand (Schleihauf and Lauder procedures) was shown to be less sensitive to errors in the digitising procedure. The reconstruction procedure proposed in this study (Lauder). further reduced the sensitivity to digitising error in the reconstruction of sweepback and pitch angles in swimming.

Barbell Kinematics Should Not Be Used to Estimate Power Output Applied to the Barbell-and-Body System Center of Mass During Lower-Body Resistance Exercise

Abstract Lake, JP, Lauder, MA, and Smith, NA. Barbell kinematics should not be used to estimate power output applied to the barbell-and-body system center of mass during lower-body resistance exercise. J Strength Cond Res 26(5): 1302–1307, 2012—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.

Mechanical demands of kettlebell swing exercise.

Abstract Lake, JP and Lauder, MA. Mechanical demands of kettlebell swing exercise. J Strength Cond Res 26(12): 3209–3216, 2012—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.

Effect of incremental exercise on initiation and movement times in a choice response, whole body psychomotor task

Objectives: To examine how exercise at moderate and maximal intensities affects performance on a choice response time, whole body psychomotor task. Methods: Subjects (n  =  12) were tested on a three-choice response time task, after rest and after exercise at 70% and 100% maximum power output (W˙max). The dependent variables were time to begin forward momentum (initiation time) and time to complete the movement (movement time). Stride time for the first and second strides and number of strides to cover first 1.1 m were also measured. Blood lactate concentrations and heart rate were recorded before and after completion of each psychomotor test. The subjects subjectively assessed the amount of effort that they used to complete the task. Results: Repeated measures analysis of variance showed a significant effect for initiation (F2,22  =  11.47, p<0.001) and movement times (F2,22  = 14.61, p<0.001). Post hoc least significant difference (LSD) tests showed that initiation time after exercise at 70% W˙max was significantly faster than that in the other two conditions. Speed of initiation after rest was significantly quicker than that after exercise at W˙max. For movement time, LSD tests showed that time after maximal exercise was significantly slower than that in the other two conditions. Stride time for the second stride showed a significant effect (F2,22  =  6.20, p<0.01). LSD tests found that time after exercise at W˙max was significantly slower in the other two conditions. Stepwise multiple regression analyses found that the increment of change, from rest, of lactate concentrations could significantly predict the increment of change in initiation (R2  =  0.40) and movement (R2  =  0.50) times. Conclusions: Exercise affects a whole body task differently from purely cognitive tasks. Central factors are probably more important than peripheral factors.

Biomechanical comparison of unilateral and bilateral power snatch lifts.

Biomechanical characteristics of the one-handed dumbbell power snatch (DBPS) were examined to determine whether significant differences existed between unilateral and bilateral weightlifting movements. Kinetic and kinematic movement data were recorded from 10 male weightlifters (mean ± SD: age: 30.2 ± 10.2 years; height: 174.2 ± 4.4 cm; body mass: 81.5 ± 14.6 kg) during one-handed dumbbell (DB) and traditional barbell (BBPS) power snatch performance with loads of ∼80% of respective lift one repetition maximums (1RM) with the use of 2 synchronized Kistler force plates and high-speed 3-dimensional video. Results highlighted asymmetry in the ground reaction force and kinematic profile of the DBPS, which deviated from the observed patterns of the bilateral movement. This study found that the nonlifting side (the side corresponding with the hand that did not hold the DB) tended to generate a greater pull phase peak vertical ground reaction forces significantly faster (p = 0.001) than the lifting side (the side corresponding with the hand that held the DB) during the DBPS. In addition, the DBPS nonlifting side catch phase loading rate was approximately double that of the lifting side loading rate (p < 0.05). These results quantify symmetrical deviations in the movement patterns of the unilateral power snatch movement both during the concentric muscular contraction of load vertical displacement, and the loading implications of unilateral landing. This asymmetry supports the contention that unilateral variations of weightlifting movements may provide a different training stimulus to athletes.

Notational analysis of sprint kayaking: Differentiating between ability levels

Sprint kayaking involves simultaneously balancing the boat and maintaining peak kayak velocity. Previous investigation focused on the technique and performance of elite competitors, however little research has compared elite and sub-elite paddlers. This study aimed to determine, using notational analysis, whether key technique factors could be identified which would provide insight for lower ability paddlers seeking to develop their paddling technique. 135 kayak paddlers (78 International; 38 national and 19 club) were recorded competing over 200 m and 500 m. For both distances higher stroke rates, shorter stroke times, and shorter glide times were indicative of elite paddlers for both men and women (P < 0.017). Using a 0 – 5 ranking scale for 22 spatial body and boat variables revealed significantly greater stroke width, forward reach, trunk rotation and leg motion in the elite (P < 0.017), indicating that amateur paddlers should incorporate greater use of the musculature in the legs and trunk to improve kayak velocity and performance.

The effect that side dominance has on barbell power symmetry during the hang power clean.

Lake, JP, Lauder, MA, and Smith, NA. The effect that side dominance has on barbell power symmetry during the hang power clean. J Strength Cond Res 24(11): 3180-3185, 2010-The aim of this study was to examine whether ground reaction force (GRF) side differences were transmitted and related to bar end power output asymmetries during hang power clean (HPC) performance and whether progressive loading would intensify this effect. Differences between the dominant (D) and nondominant (ND) side average GRFs (AGRFs) of both feet and average bar end power outputs were recorded simultaneously from 15 recreationally trained male volunteers at 30, 60, and 90% 1RM using 2 force platforms and 3 high-speed digital cameras, quantifying side dominance from perceived handedness (left- or right-side dominance [LRSD]), GRF side dominance (force side dominance [FSD]), and bar end power output side dominance (barbell side dominance [BSD]). With the exception of the LRSD condition, differences between the D and ND side AGRFs were significant (FSD: 1.8-4.3%; BSD: 5.1-6.4%, p < 0.05). Bar end power output side differences were significant for all conditions (LRSD: 1.5-5.4%; FSD: 0.5-3.4%; BSD: 3.9-5.6%, p < 0.05). Progressive loading did not significantly affect GRF side differences or the FSD average bar power side differences. However, during the LRSD and BSD conditions, the 60 and 90% side average bar power side differences were >the 30% equivalents. Average GRF side differences were not related to bar end power output side differences. Because of the consistent side difference of 4-6% investigators and strength and conditioning practitioners should exercise caution when interpreting changes in bar end power output.

Magnitude and relative distribution of kettlebell snatch force-time characteristics.

Abstract Lake, JP, Hetzler, BS, Lauder, MA. Magnitude and relative distribution of kettlebell snatch force-time characteristics. J Strength Cond Res 28(11): 3063–3072, 2014—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 performed displacing the kettlebell-and-lifter center of mass (CM), phase durations and impulse ratio (horizontal to resultant) were calculated from force data. The results of repeated-measures analysis of variance showed that: (a) vertical CM displacement was significantly larger during kettlebell snatch exercise (22 ± 4 vs. 18 ± 5 cm, p = 0.001), and vertical CM displacement was significantly larger than horizontal CM displacement, regardless of exercise (20 ± 3 vs. 7 ± 1 cm, p < 0.0001); (b) 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; (c) 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 2 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.

The effects of barbell load on countermovement vertical jump power and net impulse

ABSTRACT 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.