I belong to a gym that has a pool where I do aqua fitness classes five days a week. One year I worked with a trainer on the gym equipment. I've done yoga classes also but I've never lifted weights. We do work with water weights during aqua fitness. That has helped me stay strong.
Doing some sort of exercise is good for the body. It is good to get your heart rate up and feel strong. I'm sure if tested I would not be very strong.
"But he said to me, "My grace is sufficient for you, for my power is made perfect in weakness." Therefore I will boast all the more gladly about my weaknesses, so that Christ's power may rest on me. That is why, for Christ's sake, I delight in weaknesses, in insults, in hardships, in persecutions, in difficulties. For when I am weak, then I am strong," (2 Corinthians 12:9-10 NIV).
Sometimes I feel especially weak, physically or mentally. That's when I turn to Jesus with open arms. He is my strength for whatever situation I'm in. What a confidence He gives me! He is at my side and makes me strong. Thank you, God, for loving us enough to give us Your strength when we need it most.