Christopher Löffelmann

Advisors:
Prof. Dr. Anne Koelewijn, Marlies Nitschke (M.Sc.)

Duration:
02/2021 – 07/2021

Abstract:

Predictions of movement can have many different applications, e.g. to predict the effect of training, or in the design process. In recent years, trajectory optimization has been explored to generate predictions of walking [1] and submaximal running [2]. In these trajectory optimization problems, an objective related to energy is minimized, since it is known that humans minimize energy during walking and submaximal running. Furthermore, we have already shown that such simulations can predict the energy savings of a softer midsole material in running shoes [2].

Similarly, we would like to generate predictions of running at maximal speed, or sprinting, because this would also allow us to predict the effect of running shoes or training on sprint performance. Sprinting is different from submaximal running or walking, because instead of aiming to be energy efficient, in sprinting the goal is to generate a speed as high as possible. Therefore, the trajectory optimization problem for sprinting would also be slightly different. Previous work has shown that theoretically, a sprinter with bilateral lower-leg amputations can achieve a higher sprinting speed by employing a running strategy that is impossible with healthy legs [3]. However, so far, there has not been a rigorous validation of the kinetics and kinematics found for sprinting.

Therefore, the goal of this thesis is to set up and validate a trajectory optimization problem to predict sprinting. We will compare objectives with and without data-tracking to investigate how well sprinting can be predicted. Then, we will validate against existing kinetic and kinematic data of sprint running. Finally, we will investigate the influence of different model parameters of the calf muscle-tendon unit on the running speed. Specially, we will research if we can predict that sprinters generally have shorter moment arms in the achilles tendon [4].

References:

1. Koelewijn, Anne D. and Van den Bogert, Antonie J.: Joint contact forces can be reduced by improving joint moment symmetry in below-knee amputee gait simulations. Gait & Posture, 2016.
2. Dorschky, Eva et al.: Optimal control simulation predicts effects of midsole materials on energy cost of running. Computer methods in biomechanics and biomedical engineering, 2019.
3. Van den Bogert, Antonie J. and Ackermann, Marko: Effect of a prosthetic limb on sprint running performance. XXII Congress of the International Society of Biomechanics, 2009.
4. Lee, Sabrina S. M. and Piazza, Stephen J.: Built for speed: musculoskeletal structure and sprinting ability. Journal of Experimental Biology, 2009.