In this dissertation I examine first how the dynamicity of prepositions and the meaning of verbs interact in English motion constructions, and second what role the constructions themselves play in this interaction. I adopt a Construction Grammar perspective, which assumes that constructions can contribute to the interpretation of utterances. Based on an extensive corpus study and additional evidence from a survey on acceptability judgments, I investigate the limits of the semantic import of constructions with respect to the expression of PATH. To that end, I determine the degree of dynamicity of 19 prepositions on the basis of their frequency of occurrence in static versus dynamic utterance types. This degree of dynamicity measures a preposition's contribution to the semantics of utterances instantiating the Caused-Motion Construction (CMC) or the Intransitive-Motion Construction (IMC) with respect to the predication of a dynamic PATH. I show that a dynamic PATH needs to be lexically expressed in motion constructions, either by the preposition or by the verb, if it is not retrievable through contextual factors. This has direct repercussions for the use of prepositions in the two constructions. I show that coercion of non-dynamic prepositions into a dynamic interpretation is only possible if both the verb and the preposition inherently profile the endpoint. The power of constructions to coerce the meanings of lexical items, i.e. to influence the canonical interpretation of these items where they do not correspond to the construction's semantics, is thus much more restricted than commonly assumed. I also show that constructions are limited with respect to the number of lexical items that they can coerce in a given instantiation. The CMC and the IMC can either coerce a non-motion verb or a non-dynamic preposition, but the combination of non-motion verbs with non-dynamic prepositions yields utterances that no longer express a directional PATH. Overall, this thesis illustrates that it is indispensable to consider the lexical semantics of the instantiating verbs and their co-occurrence restrictions with specific prepositions, even when examining the workings of more abstract linguistic units such as constructions.