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Optimal coordination of maximal-effort horizontal and vertical jump motions--a computer simulation study.

ABSTRACT: BACKGROUND: The purpose of this study was to investigate the coordination strategy of maximal-effort horizontal jumping in comparison with vertical jumping, using the methodology of computer simulation. METHODS: A skeletal model that has nine rigid body segments and twenty degrees of freedom was developed. Thirty-two Hill-type lower limb muscles were attached to the model. The excitation-contraction dynamics of the contractile element, the tissues around the joints to limit the joint range of motion, as well as the foot-ground interaction were implemented. Simulations were initiated from an identical standing posture for both motions. Optimal pattern of the activation input signal was searched through numerical optimization. For the horizontal jumping, the goal was to maximize the horizontal distance traveled by the body's center of mass. For the vertical jumping, the goal was to maximize the height reached by the body's center of mass. RESULTS: As a result, it was found that the hip joint was utilized more vigorously in the horizontal jumping than in the vertical jumping. The muscles that have a function of joint flexion such as the m. iliopsoas, m. rectus femoris and m. tibialis anterior were activated to a greater level during the countermovement in the horizontal jumping with an effect of moving the body's center of mass in the forward direction. Muscular work was transferred to the mechanical energy of the body's center of mass more effectively in the horizontal jump, which resulted in a greater energy gain of the body's center of mass throughout the motion. CONCLUSION: These differences in the optimal coordination strategy seem to be caused from the requirement that the body's center of mass needs to be located above the feet in a vertical jumping, whereas this requirement is not so strict in a horizontal jumping.

SUBMITTER: Nagano A

PROVIDER: S-EPMC1896168 | biostudies-literature | 2007

REPOSITORIES: biostudies-literature

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Optimal coordination of maximal-effort horizontal and vertical jump motions--a computer simulation study.

Nagano Akinori A Komura Taku T Fukashiro Senshi S

Biomedical engineering online 20070601

<h4>Background</h4>The purpose of this study was to investigate the coordination strategy of maximal-effort horizontal jumping in comparison with vertical jumping, using the methodology of computer simulation.<h4>Methods</h4>A skeletal model that has nine rigid body segments and twenty degrees of freedom was developed. Thirty-two Hill-type lower limb muscles were attached to the model. The excitation-contraction dynamics of the contractile element, the tissues around the joints to limit the join ...[more]

PMID: 17543118

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Project description:Objectives The purpose of this study is to determine the associations between horizontal jump and sprint acceleration, as well as maximal speed performance. Methods A systematic literature search was performed using PubMed, MEDLINE (EBSCOhost), and Web of Science. The studies that were included in this review must meet the following criteria: (1) well-trained individuals over the age of 18 years old; (2) Pearson’s correlation coefficients between sprint time and horizontal jump distance were provided; (3) the sprint distance was limited to 0–100 m. The quality of the studies was assessed using a modified version of the Downs and Black Quality Index test. A random-effects model was used to determine the effect sizes, and heterogeneity between studies was examined using the Q statistic and I2. Results From the identified 2,815 studies, 27 studies were included in this study (two from reference lists). The sprint time of the sprint acceleration phase was moderately and negatively correlated with the standing long jump (r = − 0.45, z = 7.48, p < 0.001), single leg standing long jump (r = − 0.48, z = 3.49, p < 0.001) and horizontal drop jump distance (r = − 0.48, z = 3.49, p < 0.001), and was largely and negatively correlated with multiple jump distance (r = − 0.69, z = 6.02, p < 0.001). Out of five studies assessed the standing triple jump, three studies reported significant positive association with the sprint acceleration performance. The sprint time of maximal speed phase was very largely and negatively associated with standing long jump distance (r = − 0.73, z = 4.44, p < 0.001) and multiple jump distance (r = − 0.76, z = 6.86, p < 0.001). Conclusions This review indicates the moderate to very large associations between horizontal jump and sprint acceleration and maximal speed performance, and the highest magnitude of associations between them is found in the multiple jump. Moreover, compared to the sprint acceleration performance, there are greater associations between maximal speed performance and standing long jump and multiple jump distance.

Project description:BACKGROUND:In return-to-work (RTW) programs, coordinators are often provided in order to integrate services. However, models of coordinating services vary widely internationally, and across different programs, where one distinction is between vertical and horizontal integration (i.e. between levels/institutions, or within one service/level). The aim of this study was therefore to explore and describe if and how a coordinator was provided in RTW-programs, and whether the provision of a coordinator was associated with certain personal or intervention characteristics. METHODS:The study was designed as a cohort study following employees participating in a variety of Rapid-RTW-programs in Norway (n?=?39). Employees (n?=?494) answered a self-administered questionnaire, which was linked to register-data on diagnoses and sickness-absence. Employees who replied yes/no to the question "Did the program provide a person who tailored or coordinated your services?" were included in this analysis. Associations for being provided with a coordinator were tested in adjusted logistic regression models. RESULTS:Sixty-nine percent of the employees reported having a coordinator. These coordinators were mainly responsible for coordinating treatment within own programs (i.e. horizontal coordination, 68%). As expected, rehabilitation programs more often provided a coordinator compared to treatment programs (OR 3.87 95% CI 2.42-6.24). The odds for being provided with a coordinator were reduced for each additional year of age of the employee (OR 0.97, 95% CI 0.96-0.99). More professions were involved in programs that provided coordinators, also more contact with other stakeholders like leaders and social insurance services (NAV), but only contact with supervisor remained statistically significant in adjusted analysis (OR 1.69 95% CI 0.31-9.27). The programs with a coordinator more often provided adaptations at the workplace for the individual employee (OR 0.08 95% CI 0.01-0.60). However, these signs of vertical integration were only evident for a limited number of employees. CONCLUSION:In this study, seven of ten employees reported to have a coordinator, which was associated with more professions and stakeholder involvement in the RTW-process. Most of these coordinators did not coordinate vertically between the service levels and types of intervention arenas for sick listed employees (i.e. workplace, social security, and health care services), as recommended in earlier research.

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Optimal coordination of maximal-effort horizontal and vertical jump motions--a computer simulation study.

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Optimal coordination of maximal-effort horizontal and vertical jump motions--a computer simulation study.

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