Graphene nanoribbons present diverse electronic properties ranging from semi-conducting to half-metallic, depending on their geometry, dimensions and chemical composition. Here we present a route to control these properties via externally applied mechanical deformations. Using classical elasticity theory considerations, we find a remarkable Young's modulus value of ~7 TPa for ultra-narrow graphene strips. Pronounced electromechanical response towards bending and torsional deformations suggests the possible design of miniature electromechanical sensors and devices based on ultra-narrow graphene nanoribbons.