"challenging strategy" is a correct and usable phrase in written English.
You could use it, for example, in a sentence like this: "John devised a challenging strategy that allowed him to build a successful business."
Immobilization of bone morphogenetic proteins (BMP) onto material surfaces is a promising, but still challenging, strategy for achieving dependable and consistent osseointegration of long-term metal implants.
2 A challenging strategy of using antibodies to stimulate the immune response was pioneered in the mid 1990s when the role of cytotoxic T lymphocyte antigen-4 (CTLA-4) as an inhibitory signal for the T-cell response became clearer.
Demba's is an exciting, expansive, yet challenging strategy.
Would any particular denominations make the game of Dollar Nim more interesting (as defined by requiring a more challenging strategy)?
Salmon farming is discussed in relation to the challenging strategy of "sustainable intensification".
This is a more technically challenging strategy, in that intact proteins are harder to fractionate and fragment than peptides, and much harder to separate by liquid chromatography.
It is not encouraging that only one out of five interacted with others about the advice, as group coherence and social support have been expressed as essential in order to transform challenging strategies into action and goal realization [ 68].
A place to capture and share ideas, experiment with and exchange links and resources about the adoption challenges, strategy and ROI of nonprofits and social media.
The silencing of employees who sought to challenge strategy and risk-management practices likely also undermined the banks' moral authority and emboldened those who already felt inclined to do the wrong thing.
Nasal vaccination is a promising, but challenging vaccination strategy.
Back at the Antiques camp, Marty suggested Tyrone should run challenge strategy, craftily not putting himself forward.
