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Coaches often use different exercises to encourage similar strength adaptations and limit monotony. Anecdotally, the hexagonal barbell deadlift (HBD) exhibits similarities to the back squat (BS). To date, research has not examined the empirical differences between these exercises. This study examined kinematic and kinetic differences between the BS and the HBD across different loads. Sixteen resistance-trained individuals (6 men and 10 women) volunteered to participate. Subjects performed 1-repetition maximum (1RM) testing under BS and HBD conditions. Kinematic and kinetic data were collected during performance of both exercises at submaximal (warm-up sets) and maximal (1RM) loads using a 3D motion capture and force-plate system. Results showed that subjects lifted greater 1RM loads in the HBD relative to the BS (p, 0.05; d521.75). Kinematic data indicated that subjects exhibited greater maximum forward lean of the trunk and decreased maximum knee flexion while performing the HBD compared with the BS. The BS resulted in higher maximum extension moments at the hip joint than the HBD. Maximum extension moments at the knee joint showed no difference between the exercises. Data suggest that bar design and position facilitate balanced moment arm length at hip and knee joints during performance of the HBD. By contrast, bar position during performance of the BS increases moment arm length at the hip joint, making it a hip-dominant exercise. The present data have implications for the programming of both exercises. Future research should examine differences in muscle-activation strategies between the 2 exercises. [ABSTRACT FROM AUTHOR]

To be competitive internationally, figure skaters today must perform complex athletic skills such as triple axels. However, few skaters are executing such jumps consistently. In this study, a 3D kinematic analysis of five elite male skaters was undertaken to compare characteristics of single, double, and triple axels and to determine which parameters are most critical to completion of the triple axel. Results indicate that skaters increase their number of revolutions by increasing their rotational velocity, not by increasing their time in the air. The study also shows that skaters' triple axels travel horizontally only 70% as far as their single axels, an observation attributable to skaters' greater skid distances, greater takeoff angles, and consequently lower horizontal velocities in their triple axels. It appears that achieving a high rotational velocity by generating angular momentum at takeoff and by minimizing moment of inertia about the spin axis is a key to completing the triple axel. [ABSTRACT FROM AUTHOR]

Content: Lower extremity landing mechanics have been implicated as a contributing factor in knee pain and injury, yet cost effective and clinically accessible methods for evaluating movement mechanics are limited. The identification of valid, reliable, and readily accessible technology to assess lower extremity alignment could be an important tool for clinicians, coaches, and strength and conditioning specialists., Objective: The purpose of this study was to examine the validity and reliability of using a hand-held tablet and movement analysis application (app) for assessing lower extremity alignment during a drop vertical jump task., Design: Concurrent Validation., Setting: Laboratory., Participants: Twenty-two healthy college aged subjects (11 female and 11 male, mean age = 21 ± 1.4 years; mean height: 1.73 ± .12 m, mean mass: 71 ± 13 kg) with no lower extremity pathology that prevented safe landing from a drop jump., Intervention: Subjects performed six drop vertical jumps which were recorded simultaneously using a 3D motion capture system and a hand-held tablet., Main Outcome Measures: Angles on the tablet were calculated using a motion analysis app and from the 3D motion capture system using Visual 3D. Hip and knee angles were measured and compared between both systems., Results: Significant correlations between the tablet and 3D measures for select frontal and sagittal plane ranges of motion (ROM) and angles at maximum knee flexion (MKF) ranged from r = 0.48 (P = .036) for frontal plane knee angle at MKF to r = .77 (P<.001) for knee flexion at MKF., Conclusion: Results of this study suggest that a hand-held tablet and app may be a reliable method for assessing select lower extremity joint alignments during drop vertical jumps, but this technology should not be used to measure absolute joint angles. However, sports medicine specialists could use a hand-held tablet to reliably record and evaluate lower extremity movement patterns on the field or in the clinic.