Abstracts from the 8th International Conference on cGMP Generators, Effectors and Therapeutic Implications

This work was supported by a restricted research grant of Bayer AG

Comparison of Different Algorithms for Calculating Velocity and Stride Length in Running Using Inertial Measurement Units

Running has a positive impact on human health and is an accessible sport for most people. There is high demand for tracking running performance and progress for amateurs and professionals alike. The parameters velocity and distance are thereby of main interest. In this work, we evaluate the accuracy of four algorithms, which calculate the stride velocity and stride length during running using data of an inertial measurement unit (IMU) placed in the midsole of a running shoe. The four algorithms are based on stride time, foot acceleration, foot trajectory estimation, and deep learning, respectively. They are compared using two studies: a laboratory-based study comprising 2377 strides from 27 subjects with 3D motion tracking as a reference and a field study comprising 12 subjects performing a 3.2-km run in a real-world setup. The results show that the foot trajectory estimation algorithm performs best, achieving a mean error of 0.032 ± 0.274 m/s for the velocity estimation and 0.022 ± 0.157 m for the stride length. An interesting alternative for systems with a low energy budget is the acceleration-based approach. Our results support the implementation decision for running velocity and distance tracking using IMUs embedded in the sole of a running shoe

Spatially Resolved Spectroscopy of Single and Coupled Quantum Dots

Optical properties of single and coupled quantum dots are studied with high spatial resolution. Several techniques are used to resolve spectra of individual dots. Spatially isolated dots produced by double cleaved edge overgrowth are investigated by diffraction limited spectroscopy using a special microscope setup. Self-assembled InGaAs dots have been investigated by near-field optical techniques with metallic masks and by scanning tunneling microscopy cathodoluminescence. Photoluminescence and photoluminescence excitation spectra of selected quantum dots are discussed which reveal detailed information on ground and excited states as well as their coupling with neighboring dots

Does the Position of Foot-Mounted IMU Sensors Influence the Accuracy of Spatio-Temporal Parameters in Endurance Running?

Wearable sensor technology already has a great impact on the endurance running community. Smartwatches and heart rate monitors are heavily used to evaluate runners’ performance and monitor their training progress. Additionally, foot-mounted inertial measurement units (IMUs) have drawn the attention of sport scientists due to the possibility to monitor biomechanically relevant spatio-temporal parameters outside the lab in real-world environments. Researchers developed and investigated algorithms to extract various features using IMU data of different sensor positions on the foot. In this work, we evaluate whether the sensor position of IMUs mounted to running shoes has an impact on the accuracy of different spatio-temporal parameters. We compare both the raw data of the IMUs at different sensor positions as well as the accuracy of six endurance running-related parameters. We contribute a study with 29 subjects wearing running shoes equipped with four IMUs on both the left and the right shoes and a motion capture system as ground truth. The results show that the IMUs measure different raw data depending on their position on the foot and that the accuracy of the spatio-temporal parameters depends on the sensor position. We recommend to integrate IMU sensors in a cavity in the sole of a running shoe under the foot’s arch, because the raw data of this sensor position is best suitable for the reconstruction of the foot trajectory during a stride

Retrospective Analysis of Training and Its Response in Marathon Finishers Based on Fitness App Data

Objective: Finishing a marathon requires to prepare for a 42.2 km run. Current literature describes which training characteristics are related to marathon performance. However, which training is most effective in terms of a performance improvement remains unclear. Methods: We conducted a retrospective analysis of training responses during a 16 weeks training period prior to an absolved marathon. The analysis was performed on unsupervised fitness app data (Runtastic) from 6,771 marathon finishers. Differences in training volume and intensity between three response and three marathon performance groups were analyzed. Training response was quantified by the improvement of the velocity of 10 km runs Δv(10) between the first and last 4 weeks of the training period. Response and marathon performance groups were classified by the 33.3rd and 66.6th percentile of Δv(10) and the marathon performance time, respectively. Results: Subjects allocated in the faster marathon performance group showed systematically higher training volume and higher shares of training at low intensities. Only subjects in the moderate and high response group increased their training velocity continuously along the 16 weeks of training. Conclusion: We demonstrate that a combination of maximized training volumes at low intensities, a continuous increase in average running speed up to the aimed marathon velocity and high intensity runs ≤ 5 % of the overall training volume was accompanied by an improved 10 km performance which likely benefited the marathon performance as well. The study at hand proves that unsupervised workouts recorded with fitness apps can be a valuable data source for future studies in sport science

Spatially resolved magneto-optics on confined systems

We report about spatially resolved magneto-optical experiments on two different confined semiconductor systems. Using near-field spectroscopy through AFM-written shadow masks we have investigated the optical properties of single self-assembled InGaAs quantum dots as a function of excitation power and magnetic field. This allows us to identify and fully resolve diamagnetic/orbital effects and the Zeeman splitting in the ground state and excited state of a given quantum dot. Further we report on the transport properties of minority holes in a high mobility two-dimensional electron gas at finite electric fields and high magnetic fields. Making use of spatially resolved optical excitation and detection we study the propagation of optically excited minority holes within the sea of a drifting two-dimensional electron gas. At high magnetic fields we observe an E × B drift of holes which is dominated by the Hall-field of the electron gas. At the edge of the Hall-bar, we observe edge state transport of holes via skipping orbits opposite to the direction of the initial E × B drift