|how did dinosaurs stay balanced with these skinny arms?|
From time to time I’ll catch myself not using my arms while running. I nonchalantly let them kind of dangle from side to side as if they’re getting in the way. I suspect most runners don’t realize how important our arms are for propelling forward. They act like counter weights to our legs. Try running with the arms down to the sides and you’ll notice how difficult it is. The body isn’t balanced and there’s a wobble. I’m guessing that the energy coming up through the body is being absorbed completely by the core instead of being directed to the arms.
Being more deliberate with the arms helps form and running economy. I especially notice the importance of the arms (and core) while running uphill. I’m using my arms to aid in the vertical motion upwards. Compare jumping up steps with and without the use of your arms. Using only the legs to counteract gravity gets tiring real quick.
On downhills the arm movement is less pronounced, gravity is pulling us down. It’s more important to coast and have a controlled fall downward. This is when I again allow myself to have dinosaur arms and let them go a little limp.