It is highly unlikely Martin will win the 100 meters due to his lack of training. What is the correct phrasing?

The phrase "no chance of winning" accurately captures the sentiment expressed in the original sentence. It conveys the strong likelihood that Martin's lack of training will prevent him from achieving victory in the 100 meters. This choice reflects a definitive and absolute statement about the unlikelihood of success, aligning closely with "highly unlikely," which suggests virtually no chance of winning.

Other options do not encapsulate the same degree of certainty or the specific context of winning a race. For instance, "little chance of succeeding" implies there is still some possibility, which dilutes the strong implication of improbability in the original statement. Similarly, "no possibility of victory" and "high risk of failure" suggest an absolute outcome or a focus on potential failure, respectively, rather than the specific scenario of actually winning the race, which is the central concern of the original sentence. Thus, "no chance of winning" stands out as the most fitting transformation.