Background:　We　aim　to　evaluate　the　causal　relationship　between　different　types　of　physical　activity　and　the　risk　of　knee　osteoarthritis　(KOA)　through　a　two-sample　Mendelian　randomization　study.　Methods:　We　performed　a　two-sample　Mendelian　randomization　analysis　using　publicly　available　Genome-wide　association　study　associated　with　physical　activity　(460　376　individuals)　and　KOA　(403　124　individuals).　Two-sample　Mendelian　randomization　analyses　were　performed　to　investigate　the　effects　of　exposure　traits　on　KOA　risk.　Results:　In　this　Mendelian　randomization　analysis,　we　investigated　the　impact　of　different　types　of　physical　activity　on　the　risk　of　KOA.　Light　do-it-yourself　and　walking　for　pleasure　demonstrated　a　protective　effect　on　the　risk　of　KOA　(P　=　8.19　10　4　and　P　=　4.24　10　6,　respectively).　No　statistically　significant　differences　were　observed　for　heavy　do-ityourself,　strenuous　sports,　other　exercises　or　physical　inactivity.　Conclusion:　This　study　has　revealed　that　engaging　in　light　do-it-yourself　activities　and　walking　may　serve　as　potential　protective　factors　against　KOA.　These　findings　underscore　the　significance　of　introducing　such　activities　into　public　health　strategies　designed　for　the　prevention　and　management　of　KOA.　Additional　research　is　warranted　to　reveal　the　underlying　mechanisms　further.　(c)　2024　Elsevier　B.V.　All　rights　are　reserved,　including　those　for　text　and　data　mining,　AI　training,　and　similar　technologies.