The pattern matcher cries for a state machine. State 0 is IDLE, from which a transition to state 1 is made when the strain gauge input becomes >50. In state 1 you either wait for certain time (1s) before a transition into state 2, or for some unwanted strain gauge value to go back e.g. to IDLE. And so on, until a state is reached that requires to turn on (or off) the motor.