We make physical efforts when we swim, carry shopping bags, push heavy doors, or cycle up hills. A growing concern among philosophers and scientists in related fields is the absence of a well-defined concept for physical efforts. This paper addresses this issue by presenting a force-based definition of physical efforts. In Sect. 1, we explore the shortcomings of existing definitions of effort. Section 2 introduces the force-based account of efforts according to which making an effort consists in exerting a force (...) so as to make an object move or stay at rest. Section 3 introduces three central distinctions stemming from the account: failed vs. successful efforts; resisted vs. unresisted efforts; and efforts vs. effortful actions. Section 4 presents a key objection, to the effect that the force-based theory cannot account for the difficulty of efforts: efforts usually feel difficult, but effort’s difficulty is not always a function of the magnitude of force(s) exerted. Section 5 argues that the most in-depth account of difficulty so far, that developed by Bradford ( 2015 ), cannot account for the difficulty of efforts. Sections 6 & 7 develop a novel account of effort’s difficulty. (shrink)