Take a look at these two cites, its the Chinese view on why this would make complete sense. I guess you can describe this because when you are bloated, things are not moving and flowing in the body. Liquids, bowels, energy, and blood are stuck in the center and not flowing to the muscles and limbs, making them feel weak. The Spleen is in charge of digestion in chinese medicine and if it is deficient two of the symptoms are bloating and weak limbs. Read these websites its pretty interesting, hope this helps! http://docs.google.com/gview?a=v&q=cache:LWWFDV8jnAoJ:www.mybodywisdom.net/pdf/Spleen_Qi_Nutrition.pdf+spleen+qi+deficiency+bloating+weak+limbs&hl=en&gl=us