Singer-actress Jennifer Lopez doesnt need a cape to look and feel like a superhero.The "El Anillo" singer, 49, showed off her buff biceps in a clingy maroon dress and silver hoop earrings on Instagram. With her hair swept back, Lopez flexed her incredible arms as she looked confidently at the camera over her shoulder, reports people.com."Feeling like superwoman after the show tonight," Lopez wrote.In the caption, Lopez reflected on her jam-packed show at Planet Hollywood in Las Vegas, which comes to a close on September 29."When I started this run I thought omg 15 shows in 27 days that's a lot," said Lopez.She added: "But I made a promise to myself that instead of letting it wear me down I would be even stronger at the end of it?I will work out and be in the best shape of my life?""There were moments I was tired and there was travel and I had to fit in my workouts where I could... but here we are with only 3 shows left!! And I am having so many emotions but mostly just feeling strong, happy and grateful."