EE WAS LOADING 6"" PLASTIC PIPE ONTO A TRAILER WITH A FORKLIFT AND DECIDED ONE PIPE (APPROX. 50-70 LBS) NEEDED MOVED. HE DECIDED TO MOVE THIS MANUALLY WITHOUT THE HELP OF A COWORKER, OR USING THE FORKLIFT. WHILE DOING THIS, HE TWISTED WHILE LIFTING, CAUSING A LUMBAR STRAIN. EE WAS TAKEN TO AN OCCUPATIONAL CLINIC. EE RETURNED BACK TO WORK THAT DAY -RESTRICTIVE DUTY.