A method for determining strain in an object using a body for holding a fiber optic strain sensor, the body comprising a surface mountable frame which is plate-shaped, the frame comprising at least two anchor portions for enabling attachment to a surface of the object, a strain sensitive region in an intermediate position between a first anchor portion and a second anchor portion of the at least two anchor portions, a sensor connection portion configured to hold at least one strain sensor for enabling attachment of the strain sensor to the frame in the strain sensitive region, and at least one elastic portion arranged in the strain sensitive region, the elastic portion being formed by a spring structure configured to modify a strain transmission from the object to the sensor connection portion of the frame, the method comprising:
- attaching the frame to the objects by means of the at least two anchor portions,
- anchoring the strain sensor to the frame in the strain sensitive region by means of the sensor connection portion, and
- determining a value indicative of strain in the object by means of the strain sensor.