Final answer:
The nurse should implement the intervention of performing active lower extremity ROM exercises for the client with an L1 SCI to maintain muscle strength, prevent contractures, improve circulation, and maintain joint mobility.
Step-by-step explanation:
The intervention that the nurse should implement for the client with an L1 SCI is to perform active lower extremity ROM exercises. ROM exercises are important to maintain muscle strength and prevent contractures in patients with spinal cord injury (SCI). These exercises can help improve circulation, prevent blood clots, and maintain joint mobility. The rehabilitation nurse needs to assess the client's abilities and limitations before implementing ROM exercises. They can include exercises such as ankle pumps, knee bends, and hip flexion/extension within the client's range of motion.