I wanted to share a new training idea I've incorporated recently. I do a fair amount of my treadmill running holding a pool ball in each hand. They weigh about 6 oz each , and are therefore light enough not to alter my gait appreciably , yet keep my heart rate up. I've tried running with 2 lb weights and realized quickly that it didn't feel right. I find that the size and the weight of pool balls is ideal.
I know there are a lot of crazy ideas shared on this site , designed to elicit humorous responses. I'm actually sincere in sharing this tip. Just thought I'd " carom " this idea off you.