) and in overweight (solid line) groups. Kinematics Descriptive statistics of vertical jump kinematics are presented in Table 2 . The overweight group exhibited about 10° less flexion of the hip ( P = .045; Figure 2A ) and about 12° less flexion of the knee ( P = .02; Figure 2A ) at the bottom of
Jeffrey C. Cowley, Steven T. McCaw, Kelly R. Laurson and Michael R. Torry
Kym J. Williams, Dale W. Chapman, Elissa J. Phillips and Nick Ball
Purpose: To establish the influence of athlete-dependent characteristics on the generation and timing of system and individual joint powers during a countermovement jump (CMJ). Methods: Male national representative athletes from volleyball (n = 7), basketball (n = 6), and rugby (n = 7) performed a set of 3 CMJs at relative barbell loads of 0%, 10%, 20%, 30%, and 40% of absolute back-squat strength. Ground-reaction forces and joint kinematics were captured using a 16-camera motion-capture system integrated with 2 in-ground force plates. Limb lengths and cross-sectional areas were defined using 3-dimensional photonic scans. A repeated-measures analysis of variance determined the interaction between system and joint load–power profiles, whereas a multiregression analysis defined the explained variance of athlete-dependent characteristics on the load that maximized system power. Results: System and isolated hip, knee, and ankle peak powers were maximized across a spectrum of loads between and within sports; power values were not significantly different across loads. A positive shift in the timing of hip and ankle peak powers corresponded to a significant (P < .05) positive shift in the timing of system peak power to occur closer to toe-off. An optimal 3-input combination of athlete-dependent characteristics accounted for 68% (P < .001) of the explained variance in the load that maximized system peak power. Conclusion: The load maximizing system power is athlete-dependent, with a mixture of training and heredity-related characteristics influencing CMJ load–power profiles. The authors recommend that a combination of relative loads be individually prescribed to maximize the generation and translation of system CMJ power.
Bradley S. Beardt, Myranda R. McCollum, Taylour J. Hinshaw, Jacob S. Layer, Margaret A. Wilson, Qin Zhu and Boyi Dai
-takeoffs, but were similar and strongly correlated between the 2 volleyball-takeoffs. Drop-jump kinematics may not represent jump-landing kinematics exhibited during volleyball competition. Although screening jump-landing mechanics during sports competition may provide unique value in screening, jump
Marianne Haguenauer, Pierre Legreneur and Karine M. Monteil
To our knowledge jumping kinematics have never been studied in elderly persons. This study was aimed at examining the influence of aging on vertical jump performance and on interjoint coordination. Two groups of adults, 11 young men ages 18–25 years and 11 older men ages 79–100 years, were filmed while performing a maximal squat jump. Compared to young adults, jump height was significantly decreased by 28 cm in the elderly. Older adults spontaneously jumped from a more extended position of the hip. Results showed a decrease in hip, knee, and ankle linear velocity and angular amplitude with aging. The decrease in jump height was attributed to a decrease in explosive force and in the range of shortening of extensor muscles. In agreement with the literature, a proximo-distal coordination pattern was observed in young adults. Older adults used a simultaneous pattern. This may indicate that adults adjust their pattern of joint coordination as they age.
Yuji Kobayashi, Junjiro Kubo, Takeo Matsubayashi, Akifumi Matsuo, Kando Kobayashi and Naokata Ishii
The aims of the study were to investigate the differences in kinematics and kinetics between the dominant and nondominant leg during single-leg jumps without arm swing, and to determine the relationship between bilateral asymmetry in isokinetic knee strength and the single-leg jump. Isokinetic knee strength and single-leg jump kinematics and kinetics were measured in 11 male participants. The bilateral asymmetry index was calculated for each parameter. For isokinetic knee strength, there were no significant differences between the dominant and nondominant legs. Significant correlations were observed for the bilateral asymmetry index for isokinetic knee strength at 180 degrees per second and the bilateral asymmetry indexes for maximum flexion angle and the mean knee joint torque during the single-leg jumps. In conclusion, the findings of the current study suggest an association between knee strength imbalances and the joint angle, as well as the torque produced in single-leg jumps, although no relationship between knee strength and jump height was observed.
Kajetan J. Słomka, Slobodan Jaric, Grzegorz Sobota, Ryszard Litkowycz, Tomasz Skowronek, Marian Rzepko and Grzegorz Juras
direct measurement of ground reaction forces ( Cormie, McBride, & McCaulley, 2008 ; Mandic et al., 2016 ), the recorded jumping kinematics ( García-Ramos, Jaric, Pérez-Castilla, Padial, & Feriche, 2017 ), or both ( Salles, Baltzopoulos, & Rittweger, 2011 ). These studies interpret jump force and power
Guilherme S. Nunes, Débora Faria Wolf, Daniel Augusto dos Santos, Marcos de Noronha and Fábio Viadanna Serrão
Patellofemoral Pain, Mean (SD) Squatting Jumping Difference within groups Difference between groups (95% CI) Exp Sham Exp Sham Squatting Jumping Variables Pre (n = 14) Post (n = 14) Pre (n = 14) Post (n = 14) Pre (n = 14) Post (n = 14) Pre (n = 14) Post (n = 14) Exp Sham Exp Sham Squatting Jumping Kinematics
Gustavo Ramos Dalla Bernardina, Tony Monnet, Heber Teixeira Pinto, Ricardo Machado Leite de Barros, Pietro Cerveri and Amanda Piaia Silvatti
negligible for human 3D kinematic analysis. In this study, we adopted 4 cameras and only one testing subject. However, the aim was to examine the potential of the gait and jump kinematics assessment and not an extensive validation. In future works, a setup with more cameras and more subjects will be
Antonio Dello Iacono, Marco Beato and Israel Halperin
the ground as hard and fast as possible during the upward movement, and to jump in a ballistic manner as high as possible. To minimize variation in jump kinematic and kinetic patterns, jump squat depth was standardized using an adjustable rod placed on a tripod, and a manual goniometer was used to set
Zachary M. Gillen, Lacey E. Jahn, Marni E. Shoemaker, Brianna D. McKay, Alegra I. Mendez, Nicholas A. Bohannon and Joel T. Cramer
of methods for analyzing drop jump performance . Med Sci Sports Exerc . 1999 ; 31 ( 3 ): 437 – 442 . PubMed ID: 10188749 doi:10.1097/00005768-199903000-00013 10188749 10.1097/00005768-199903000-00013 27. Meylan C , Cronin J , Oliver J , Hughes M , McMaster T . The reliability of jump