Micromotor-mediated sperm constrictions for improved swimming performance Friedrich Striggow, Lidiia Nadporozhskaia, Benjamin M. Friedrich, Oliver G. Schmidt and Mariana Medina-Sánchez Eur. Phys. J. E, 44 5 (2021) 67 Published online: 11 May 2021 DOI: 10.1140/epje/s10189-021-00050-9