The Experts below are selected from a list of 44328 Experts worldwide ranked by ideXlab platform

David Lentink - One of the best experts on this subject based on the ideXlab platform.

  • the aerodynamic Force Platform as an ergometer
    The Journal of Experimental Biology, 2020
    Co-Authors: Marc E Deetjen, Diana D Chin, David Lentink
    Abstract:

    Animal flight requires aerodynamic power, which is challenging to determine accurately in vivo. Existing methods rely on approximate calculations based on wake flow field measurements, inverse dynamics approaches, or invasive muscle physiological recordings. In contrast, the external mechanical work required for terrestrial locomotion can be determined more directly by using a Force Platform as an ergometer. Based on an extension of the recent invention of the aerodynamic Force Platform, we now present a more direct method to determine the in vivo aerodynamic power by taking the dot product of the aerodynamic Force vector on the wing with the representative wing velocity vector based on kinematics and morphology. We demonstrate this new method by studying a slowly flying dove, but it can be applied more generally across flying and swimming animals as well as animals that locomote over water surfaces. Finally, our mathematical framework also works for power analyses based on flow field measurements.

  • design and analysis of aerodynamic Force Platforms for free flight studies
    Bioinspiration & Biomimetics, 2017
    Co-Authors: Ben Hightower, Rivers Ingersoll, Diana D Chin, Carl Lawhon, Andreas F. Haselsteiner, David Lentink
    Abstract:

    : We describe and explain new advancements in the design of the aerodynamic Force Platform, a novel instrument that can directly measure the aerodynamic Forces generated by freely flying animals and robots. Such in vivo recordings are essential to better understand the precise aerodynamic function of flapping wings in nature, which can critically inform the design of new bioinspired robots. By designing the aerodynamic Force Platform to be stiff yet lightweight, the natural frequencies of all structural components can be made over five times greater than the frequencies of interest. The associated high-frequency noise can then be filtered out during post-processing to obtain accurate and precise Force recordings. We illustrate these abilities by measuring the aerodynamic Forces generated by a freely flying bird. The design principles can also be translated to other fluid media. This offers an opportunity to perform high-throughput, real-time, non-intrusive, and in vivo comparative biomechanical measurements of Force generation by locomoting animals and robots. These recordings can include complex bimodal terrestrial, aquatic, and aerial behaviors, which will help advance the fields of experimental biology and bioinspired design.

  • In vivo recording of aerodynamic Force with an aerodynamic Force Platform: From drones to birds
    Journal of the Royal Society Interface, 2015
    Co-Authors: David Lentink, Andreas F. Haselsteiner, Rivers Ingersoll
    Abstract:

    Flapping wings enable flying animals and biomimetic robots to generate elevated aerodynamic Forces. Measurements that demonstrate this capability are based on experiments with tethered robots and animals, and indirect Force calculations based on measured kinematics or airflow during free flight. Remarkably, there exists no method to measure these Forces directly during free flight. Such in vivo recordings in freely behaving animals are essential to better understand the precise aerodynamic function of their flapping wings, in particular during the downstroke versus upstroke. Here, we demonstrate a new aerodynamic Force Platform (AFP) for non-intrusive aerodynamic Force measurement in freely flying animals and robots. The Platform encloses the animal or object that generates fluid Force with a physical control surface, which mechanically integrates the net aerodynamic Force that is transferred to the earth. Using a straightforward analytical solution of the Navier-Stokes equation, we verified that the method is accurate. We subsequently validated the method with a quadcopter that is suspended in the AFP and generates unsteady thrust profiles. These independent measurements confirm that the AFP is indeed accurate. We demonstrate the effectiveness of the AFP by studying aerodynamic weight support of a freely flying bird in vivo. These measurements confirm earlier findings based on kinematics and flow measurements, which suggest that the avian downstroke, not the upstroke, is primarily responsible for body weight support during take-off and landing.

Shayne Taback - One of the best experts on this subject based on the ideXlab platform.

  • Force Platform feedback for standing balance training after stroke
    Stroke, 2005
    Co-Authors: Ruth Barclaygoddard, Ted J Stevenson, William Poluha, Michael E K Moffatt, Shayne Taback
    Abstract:

    Standing balance deficits are common in individuals after stroke. One way to address these deficits is to provide the individual with feedback from a Force Platform while balance activities are performed. The feedback can take visual and/or auditory form. Our goal was to determine if visual or auditory Force Platform feedback improves the clinical and Force Platform standing balance outcomes in clients with stroke. We searched the Cochrane Stroke Group trials register (last searched December 2003) and the following electronic bibliographic databases: the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 3, …

  • Force Platform feedback for standing balance training after stroke
    Cochrane Database of Systematic Reviews, 2004
    Co-Authors: Ruth Barclaygoddard, Ted J Stevenson, William Poluha, Michael E K Moffatt, Shayne Taback
    Abstract:

    Background Standing balance deficits are common in individuals after stroke. One way to address these deficits is to provide the individual with feedback from a Force Platform while balance activities are performed. The feedback can take visual and/or auditory form. Objectives To determine if visual or auditory Force Platform feedback improves the clinical and Force Platform standing balance outcomes in clients with stroke. Search methods We searched the Cochrane Stroke Group trials register (last searched December 2003), and the following electronic bibliographic databases: the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 3, 2003), MEDLINE (1966 to May 2003), EMBASE (1974 to May 2003), CINAHL (1982 to May 2003), PEDro (May 2003), CIRRIE (May 2003) and REHABDATA (May 2003). Reference lists of articles were reviewed and manufacturers of equipment were contacted. Selection criteria Randomized controlled trials comparing Force Platform with visual feedback and/or auditory feedback to other balance treatments. Data collection and analysis Two reviewers independently assessed trials for inclusion, methodological quality, and data extraction. Trials were combined for meta-analysis according to outcome and type of feedback. Main results We included seven trials (246 participants). Force Platform feedback did not improve clinical measures of balance when moving or walking (Berg Balance Scale and Timed Up and Go). Significant improvements in laboratory Force Platform indicators of stance symmetry were found for regimens using visual feedback (standardised mean difference (SMD) -0.68, 95% confidence interval (CI) -1.31 to -0.04, p = 0.04) and the concurrent visual and auditory feedback (weighted mean difference (WMD) -4.02, 95% CI -5.99 to -2.04, p = 0.00007). There were no significant effects on laboratory postural sway indicators, clinical outcomes or measures of function at follow-up assessment. Authors' conclusions Force Platform feedback (visual or auditory) improved stance symmetry but not sway in standing, clinical balance outcomes or measures of independence.

Ruth Barclaygoddard - One of the best experts on this subject based on the ideXlab platform.

  • Force Platform feedback for standing balance training after stroke
    Stroke, 2005
    Co-Authors: Ruth Barclaygoddard, Ted J Stevenson, William Poluha, Michael E K Moffatt, Shayne Taback
    Abstract:

    Standing balance deficits are common in individuals after stroke. One way to address these deficits is to provide the individual with feedback from a Force Platform while balance activities are performed. The feedback can take visual and/or auditory form. Our goal was to determine if visual or auditory Force Platform feedback improves the clinical and Force Platform standing balance outcomes in clients with stroke. We searched the Cochrane Stroke Group trials register (last searched December 2003) and the following electronic bibliographic databases: the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 3, …

  • Force Platform feedback for standing balance training after stroke
    Cochrane Database of Systematic Reviews, 2004
    Co-Authors: Ruth Barclaygoddard, Ted J Stevenson, William Poluha, Michael E K Moffatt, Shayne Taback
    Abstract:

    Background Standing balance deficits are common in individuals after stroke. One way to address these deficits is to provide the individual with feedback from a Force Platform while balance activities are performed. The feedback can take visual and/or auditory form. Objectives To determine if visual or auditory Force Platform feedback improves the clinical and Force Platform standing balance outcomes in clients with stroke. Search methods We searched the Cochrane Stroke Group trials register (last searched December 2003), and the following electronic bibliographic databases: the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 3, 2003), MEDLINE (1966 to May 2003), EMBASE (1974 to May 2003), CINAHL (1982 to May 2003), PEDro (May 2003), CIRRIE (May 2003) and REHABDATA (May 2003). Reference lists of articles were reviewed and manufacturers of equipment were contacted. Selection criteria Randomized controlled trials comparing Force Platform with visual feedback and/or auditory feedback to other balance treatments. Data collection and analysis Two reviewers independently assessed trials for inclusion, methodological quality, and data extraction. Trials were combined for meta-analysis according to outcome and type of feedback. Main results We included seven trials (246 participants). Force Platform feedback did not improve clinical measures of balance when moving or walking (Berg Balance Scale and Timed Up and Go). Significant improvements in laboratory Force Platform indicators of stance symmetry were found for regimens using visual feedback (standardised mean difference (SMD) -0.68, 95% confidence interval (CI) -1.31 to -0.04, p = 0.04) and the concurrent visual and auditory feedback (weighted mean difference (WMD) -4.02, 95% CI -5.99 to -2.04, p = 0.00007). There were no significant effects on laboratory postural sway indicators, clinical outcomes or measures of function at follow-up assessment. Authors' conclusions Force Platform feedback (visual or auditory) improved stance symmetry but not sway in standing, clinical balance outcomes or measures of independence.

Rivers Ingersoll - One of the best experts on this subject based on the ideXlab platform.

  • design and analysis of aerodynamic Force Platforms for free flight studies
    Bioinspiration & Biomimetics, 2017
    Co-Authors: Ben Hightower, Rivers Ingersoll, Diana D Chin, Carl Lawhon, Andreas F. Haselsteiner, David Lentink
    Abstract:

    : We describe and explain new advancements in the design of the aerodynamic Force Platform, a novel instrument that can directly measure the aerodynamic Forces generated by freely flying animals and robots. Such in vivo recordings are essential to better understand the precise aerodynamic function of flapping wings in nature, which can critically inform the design of new bioinspired robots. By designing the aerodynamic Force Platform to be stiff yet lightweight, the natural frequencies of all structural components can be made over five times greater than the frequencies of interest. The associated high-frequency noise can then be filtered out during post-processing to obtain accurate and precise Force recordings. We illustrate these abilities by measuring the aerodynamic Forces generated by a freely flying bird. The design principles can also be translated to other fluid media. This offers an opportunity to perform high-throughput, real-time, non-intrusive, and in vivo comparative biomechanical measurements of Force generation by locomoting animals and robots. These recordings can include complex bimodal terrestrial, aquatic, and aerial behaviors, which will help advance the fields of experimental biology and bioinspired design.

  • In vivo recording of aerodynamic Force with an aerodynamic Force Platform: From drones to birds
    Journal of the Royal Society Interface, 2015
    Co-Authors: David Lentink, Andreas F. Haselsteiner, Rivers Ingersoll
    Abstract:

    Flapping wings enable flying animals and biomimetic robots to generate elevated aerodynamic Forces. Measurements that demonstrate this capability are based on experiments with tethered robots and animals, and indirect Force calculations based on measured kinematics or airflow during free flight. Remarkably, there exists no method to measure these Forces directly during free flight. Such in vivo recordings in freely behaving animals are essential to better understand the precise aerodynamic function of their flapping wings, in particular during the downstroke versus upstroke. Here, we demonstrate a new aerodynamic Force Platform (AFP) for non-intrusive aerodynamic Force measurement in freely flying animals and robots. The Platform encloses the animal or object that generates fluid Force with a physical control surface, which mechanically integrates the net aerodynamic Force that is transferred to the earth. Using a straightforward analytical solution of the Navier-Stokes equation, we verified that the method is accurate. We subsequently validated the method with a quadcopter that is suspended in the AFP and generates unsteady thrust profiles. These independent measurements confirm that the AFP is indeed accurate. We demonstrate the effectiveness of the AFP by studying aerodynamic weight support of a freely flying bird in vivo. These measurements confirm earlier findings based on kinematics and flow measurements, which suggest that the avian downstroke, not the upstroke, is primarily responsible for body weight support during take-off and landing.

H Hanscheid - One of the best experts on this subject based on the ideXlab platform.

  • identification of factors associated with risk of fall using a Force Platform and power spectrum analysis technique
    Journal of Biomechanics, 2011
    Co-Authors: P Schneider, M Schwab, H Hanscheid
    Abstract:

    The purpose of this retrospective study was to investigate some parameters of neuromuscular performance of the lower limbs in a population cross-section and their relationship to the risk of falls, using a Force Platform (FP). Individuals from the Lower Franconia population were invited by public advertisement. Out of a total of 1720 invited subjects 50-90 years of age, the successful completion of all tests were achieved by 807 women, age 66.4±9.3, and 442 men, age 64.0±9.2. A novel FP measured the time series of vertical Forces over 10 s during 3 kinds of tests: tandem stand with eyes closed, knee bends, and chair rise. Proprietary software captured the peak Force and calculated the power density distribution (PSD), intended to characterize balance and power through the FP. Grip strength as a common geriatric Force test was dynamometrically measured for comparison. The parameters were related to the number of falls in the past 12 months in both genders. Mean PSD showed little age dependency and was not related to falls in tandem stance. Peak Forces and power over 10 s knee bends showed a larger age-related decrease in men than in women and these parameters were related to falls (p<0.001), whereas they were not related to falls in the chair rise test. Chair rise time and grip strength was related to falls in women (p<0.01). The PSD obtained from the tandem test with eyes closed did not provide a sensitive parameter associated with falls. Knee bends may be a meaningful FP screening test that justifies further studies of physical performance related to the risk of falls, whereas chair rise and grip measurements provided inferior information in this study.

  • assessment of neuromuscular function with a new ground reaction Force Platform using power spectrum analysis technique
    2009
    Co-Authors: P Schneider, M Schwab, H Hanscheid, Franz Jakob
    Abstract:

    In the elderly, sarcopenia is leading to frailty, increased risk of fall and osteoporosis. Two categories of muscle function related tests in geriatrics can estimate physical performance and sarcopenia associated with falls: movement and balance during stance.