Spring & Summer 2020

Eryn Gerber (Bioengineering MS/PhD Student) presented a poster in the ASB 2020 Annual Meeting hosted virtually. The study explored the use of rembling and trembling on center of pressure (COP) time series to determine if they could differentiate between different somatosensory deficiciency levels (i.e. foam thicknesses) and visual conditions (eyes open and closed). It was found that COP velocity, and its respective rembling and trembling time series showed significant differences for eyes closed between the highest somatosensory deficiency and no deficiency. In addition, it was shown that COP jerk rembling for eyes closed in the anterior-posterior direction showed the highest sensitivity to diferentiate multiple somatosensory deficiencies (i.e. foam levels). Eryn's poster was based on her MS Thesis work, which she defended over the Summer of 2020.

Paris Nichols (Mechanical Engineering MS) presented a poster in the ASB 2020 Annual Meeting hosted virtually. The first aim of the study was to determine the best practices of Sample Entropy and Fuzzy Sample Entropy on the center of pressure (COP) time series obtained from healthy subjects who received multiple levels of somatosensory deficiency (i.e. foam levels). Through a parameter study on both entropies, it was found that for the used data, values of m = 2 and R = 3*RoN maximize the differences between somatosensory deficiencies. The second aim of the study was to determine which entropy calculation could differentiate better levels of somatosensory deficiency. It was found that Sample Entropy outperformed Fuzzy Sample Entropy, since Sample Entropy could differentiate 3 levels of deficiency while Fuzzy Sample Entropy could only differetiate 1. This work's significance can be divided in two: 1) It shows the importance of conciously selecting entropy parameters. Unfortunately, it is possible to irresponsibly select parameters, and still get an answer. 2) It furthers the list of measures that can measure and quantify human balance. Paris' poster was based on his MS Thesis work, which he defended over the Summer of 2020.

Brett Whorley (Bioengineering MS/PhD Student) mentored Austin Gartner (Mechanical Engineering Undergraduate Student) on the initial analysis of white noise sub-threshold vibration at the feet on people's center of pressure. Austin's project used the newly vibrating mat at the laboratory, and obtained similar results to already published studies. It was found that that white and sub-threshold vibration under the feet had an immediate effect on people's center of pressure in the anterior-posterior direction. The significance of Austin's work to the Biodynamics Laboratory is that it shows that our vibrating mat can obtain results that other labs have obtained, which partially validates our system. Brett, in addition to mentor Austin, succesfully defended his MS Thesis over the Summer of 2020. His MS Thesis explored a new method to determine sensing threshold by determining if it had any effects on people's balance, and how reliable it is. For more information, visit the Projects tab.

Finally, Eryn and Brett completed their qualifying exams, meaning that they are ready to continue their doctoral work!

Fall & Winter 2019

Conferences, Defenses and Papers

Camilo Giraldo (Mechanical Engineering PhD Student) presented a poster in the BMES 2019 Annual Meeting hosted in Philadelphia. The study showed that the single inverted pendulum (SIP) mechanical model is neither perfect or wrong for unperturbed sway studies in healthy old adults and people with mild Parkinson's disease. It was found that the SIP mechanical model accuracy is sensitive to initial conditions; but not to the linearization of the equations or motion. The significance of this study is that the sway models that use a SIP are not all wrong; meaning that the studies dedicated to model sway using a SIP are not pointless and useless. This is an important statement to make today since there has been negative criticism about the usage of the SIP as the mechanical model in sway studies. Camilo will focus next on publishing this study, and looking for new forms of optimizing the presented methodology.

Brett Whorley (Bioengineering MS/PhD Student) presented on Absorb-Do-Connect Learning Units (ADCLU's) at American Society of Engineering Education Midwest Section Conference in September 2019 in Wichita, KS. ADCLU's are the new pedagogy that Dr. Luchies has implemented into his graduate-level mechanical modeling course. Students have self-reported higher levels of motivation and engagement under the ADCLU framework when compared to standard active learning. This ongoing work is part of Dr. Luchies' efforts to improve engineering education for the 21st century.

Research Projects

Eryn Gerber (Bioengineering MS/PhD Student) and Paris Nichols (Mechanical Engineering MS Student) continued with the collection of data of healthy young subjects standing on different levels of foam. Different levels of foam under the feet has the potential of simulating the somatosensory deficiency (loss of feeling at the feet) that elderly populations experience. In a previous study conducted by Logan Sidener, he found that it is possible to detect a difference between no foam and a large foam using machine learning algorithms. However, he concluded that not until more data is available, it is not possible to say if different foam levels create significant differences in healthy sway. Now that more data is available, Eryn and Paris are using new strategies to determine if there are multiple significant differences across multiple foam levels (more than no foam and large foam), and to determine if they simulate reliable somatosensory deficiencies. Eryn and Paris will be sharing their discoveries in their MS thesis, journal papers or conferences presentations/posters.

Using the data collected from healthy subjects standing on foam, Renee Kryk (Mechanical Engineering BS Student) completed her undergraduate research project (ME 360) under the supervision of Eryn Gerber. Renee did an initial exploration on the significant differences between multiple foam levels, visual conditions and sway trajectory (Anterior-Posterior and Medial-Lateral). Thanks to Renee's initial analysis, the Biodynamics Lab has now a better idea of the possibility of foam simulating the somatosensory deficiency elderly populations experience.

If foam realistically simulates somatosensory deficiency, it would be possible to test balance improvement treatments on healthy subjects standing on foam; instead of testing them on elderly populations who have lost some of their sensation at their feet. This reduces human risk! It is understood that the only way to know if something works is by testing it in the population that is intended for; however, these studies could open an additional middle point between a treatment idea and a product.

Finally, the Biodynamics Lab research team worked on the fabrication of the vibrating mat that will allow the start of multiple studies in the Spring of 2020. Now that the vibrating mat has been manufactured, the Biodynamics Lab is going to explore the effects of mechanical vibration on balance, and to determine if mechanical vibration is a possible non-invasive treatment for balance deficiency. This new piece of equipment offers the following features:

  • It determines sensation threshold under 2 minutes
  • It creates mechanical vibrations up to 12 Newtons for a range of static loads of 80 to 240 pounds
  • It outputs different types of mechanical vibrations

A more detailed description of the vibrating mat will be shared in 2020 in the form of a research article, or conference presentation/poster.


In August 2019, Brett was a summer program mentor for Design the Future, a national summer program that pairs high school students with local community members living with disabilities. Throughout the week, students work in teams to design and develop custom assistive technologies to improve independent daily living for their project partners. Brett's group worked with an incoming KU freshman who needed a better way to store and access her personal items when using her wheelchair. Read more about Design the Future in the Lawrence Journal-World, here:  https://www2.ljworld.com/news/schools/2019/aug/11/summer-stem-camp-challenges-students-to-design-products-for-people-with-disabilities/