Force generating protein component of the outer dynein arms (ODAs) in the sperm flagellum (PubMed:32619401). Produces force towards the minus ends of microtubules (PubMed:32619401). Key component of dynein, a family of motor proteins essential for movement along microtubules (By similarity). Dynein has ATPase activity; the force- producing power stroke is thought to occur on release of ADP (PubMed:32619401). Involved in sperm motility; implicated in sperm flagellar assembly (PubMed:32619401). {ECO:0000250|UniProtKB:Q22A67, ECO:0000269|PubMed:32619401}. This is the function of ENSG00000124721 (DNAH8, dynein axonemal heavy chain 8).