Weighted vest effects on impact forces and joint work during vertical jump landings in men and women

Harry, John R.; James, C. Roger; Dufek, Janet S.

doi:10.1016/j.humov.2018.12.001

Cited by 12 publications

(16 citation statements)

References 38 publications

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“…When presented with a physical task, an individual attempts to approach the problem by minimizing energy demand, however, they are limited by their physical capabilities 1 . For example, the ability to conserve energy during a DJ from increasing drop heights (increasing eccentric load) would require a certain level of strength distributed among the available functional units in the proper sequencing 20 . In a human bipedal system, this is represented by how much force a person can exert with their legs and which joints are utilized (hip, knee, ankle) to effectively develop an adequate response 21 .…”

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confidence: 99%

Biological system energy algorithm reflected in sub-system joint work distribution movement strategies: influence of strength and eccentric loading

McBride

Nimphius

2020

Sci Rep

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To better understand and define energy algorithms during physical activity as it relates to strength and movement strategy of the hip, knee and ankle, a model of increasing eccentric load was implemented in the current investigation utilizing a countermovement jump and a series of drop jumps from different heights (15, 30, 45, 60, 75 cm). Twenty-one participants were grouped by sex (men, n = 9; women, n = 12) and muscle strength (higher strength, n = 7; moderate strength, n = 7; lower strength, n = 7) as determined by a maximal squat test. Force plates and 3D motion capture were utilized to calculate work for the center of mass (COM) of the whole body and individually for the hip, knee and ankle joints. Statistically significant lower net work of the COM was observed in women and lower strength participants in comparison to men and moderate strength and higher strength participants respectively (p ≤ 0.05). This was primarily due to higher negative to positive work ratios of the COM in women and lower strength participants during all jumps. Furthermore, the COM negative work was primarily dissipated at the knee joint in women and in the lower strength group, particularly during the higher drop jump trials, which are representative of a demanding eccentric load task. A definitive energy algorithm was observed as a reflection of altering joint work strategy in women and lower strength individuals, indicating a possible role in knee joint injury and modulation of such by altering muscular strength. An energy algorithm is defined by the instructional nature of optimization and efficiency of movement in a biological system and is vital to the capacity of the performer 1-3. This energy algorithm is the transference of negative and positive work and is a representation of the component changes in potential, kinetic and stored elastic energy during a given physical activity, such as jumping 4-6 (Fig. 1). One's system efficiency is the transfer accountability of these energies effectively 7. Tissue viscoelasticity, which is determined by the collagenous and protein structures within the biological subsystem , influences energy storage and dissipation of energy as heat via muscle-tendon dynamics 8. Additionally, there is work contributed from active muscle action, which is fueled by chemical bond energy of either the beta or gamma phosphate group in adenosine triphosphate. The balance of negative and positive work of the center of mass (COM) performed during the eccentric (downward motion) and concentric (upward motion) components of a stretch-shortening cycle are vital to maximizing both performance (i.e. jump height) and economy (i.e. mechanical efficiency) 5,9-13. The energy algorithm for a whole biological system's COM is controlled by subsystem characteristics which is the distribution of work of the corresponding joints (hip, knee, ankle) in a bipedal, tri-articulate model 14. Movement strategy, which is the modulation of hip, knee and ankle work ratios, can ultimately be observed as the acceleration of the COM of the...

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confidence: 99%

Biological system energy algorithm reflected in sub-system joint work distribution movement strategies: influence of strength and eccentric loading

McBride

Nimphius

2020

Sci Rep

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“…26,27 Furthermore, the elbow joint rotation changed the body center of mass position, so the load accommodation strategy was different for the subject. 28 This effect is even more noticeable with higher external loads since it is harder for the subject to maintain the same balance level with a larger load.…”

Section: Resultsmentioning

confidence: 99%

Optimization-based subject-specific planar human vertical jumping prediction: Effect of elbow flexion and weighted vest

Baus

Harry

Yang

2021

Proc Inst Mech Eng H

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Jumping strategies differ considerably depending on athletes’ physical activity demands. In general, the jumping motion is desired to have excellent performance and low injury risk. Both of these outcomes can be achieved by modifying athletes’ jumping and landing mechanics. This paper presents a consecutive study on the optimization-based subject-specific planar human vertical jumping to test different loading conditions (weighted vest) during jumping with or without elbow flexion during the arm-swing based on the validated prediction model in the first part of this study. The sagittal plane skeletal model simulates the weighting, unweighting, breaking, propulsion phases and considers four loading conditions: 0%, 5%, 10%, and 15% body weight. Results show that the maximum ground reaction forces, the body center of mass position, and velocities at the take-off instant are different for different loading conditions and with/without elbow flexion. The optimization formulation is solved using MATLAB® with 35 design variables with 197 nonlinear constraints for a five-segment body model and 42 design variables with 227 nonlinear constraints for a six-segment body model. Both models are computationally efficient, and they can predict ground reaction forces, the body center of mass position, and velocity. This work is novel in the sense that presents a simulation model capable of considering different external loading conditions and the effect of elbow flexion during arm swing.

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“…In addition to kinetic and kinematic parameters, the advanced Anybody musculoskeletal model and reverse dynamics analysis could calculate 3D net torque, power, and work of the ankle joint. Many studies showed that vGRF increased significantly as the jumping height increased [10,[24][25][26][27], indicating that GRF suffered by subjects was positively correlated with the height. While T-PvGRF reflected landing buffering capacity in the early landing stage, this study showed that increasing the height significantly decreased T-PvGRF, which demonstrated body instability and center-of-mass deviation.…”

Section: Discussionmentioning

confidence: 99%

A novel prophylactic parachute ankle brace CPAB

Zhou

et al. 2020

Preprint

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Background: Comparing the effects of a self-designed and self-manufactured novel prophylactic ankle brace (Chinese parachute ankle brace, CPAB) and two ordinary ankle braces on the ankle joint during a half-squat parachute landing via biomechanical assessment.Methods: Twenty elite paratroopers were in four different conditions: no brace, elastic brace, semi-rigid brace, and CPAB. Each participant was instructed to jump off a platform with three different heights, 40 cm, 80 cm, and 120 cm, and land on the AMTI force plate in a half-squat posture. The vertical ground reaction forces (vGRF), joint angles, moments, powers, and works were calculated. After the experiment, every participant completed the questionnaires designed for this study.Result: Increasing the dropping height increased all of the parameters significantly (P<0.01), except for time to peak vGRF (T-PvGRF). Applying three braces can all slightly increase vGRF (P=0.237) and reduce T-PvGRF by 6-10 ms, as well as decrease the joint angles, velocities, and moments on the sagittal and coronal planes. Wearing CPAB and a semi-rigid brace more efficiently restricted dorsiflexion and inversion (P<0.05), and they both significantly reduced ankle work (t=5.107, P<0.01; t=3.331, P<0.01) and peak power (t=7.237, P<0.01; t=6.711, P<0.01) at 120 cm. The total scores from low-to-high were semi-rigid brace (19.20±2.99), elastic brace (21.91±3.25), and CPAB (23.37±3.08).Conclusion: The CPAB was more effective at restricting ankle joint motion on the coronal and sagittal planes than the other two prophylactic ankle braces. Therefore, the CPAB had the advantages of a novel appearance, high efficiency, and superior comfort, providing a reliable choice for parachute jumping and training in China.

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Weighted vest effects on impact forces and joint work during vertical jump landings in men and women

Cited by 12 publications

References 38 publications

Biological system energy algorithm reflected in sub-system joint work distribution movement strategies: influence of strength and eccentric loading

Biological system energy algorithm reflected in sub-system joint work distribution movement strategies: influence of strength and eccentric loading

Optimization-based subject-specific planar human vertical jumping prediction: Effect of elbow flexion and weighted vest

A novel prophylactic parachute ankle brace CPAB

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