Valve assemblies for reciprocating downhole pumps are provided. The valve assembly may comprise: a flow cage comprising a housing and a tubular insert; an annular valve seat positioned below the tubular insert; and an elongated sealing member positioned above the annular valve seat and at least partially received into the tubular insert. In some embodiments, the elongated sealing member may be more stable and may more securely engage the valve seat compared to spherical valve balls. Related methods are also provided.