This is perhaps the most important thing I learned in Japan; for people who work with their hands the most precious tool of all is the body. I had previously noticed when working with German carpenters that they have good posture and lift things well, bending the knees even to lift light objects. The Japanese take things further and each morning started with 5 minutes warm up exercises. I would love to see this adopted on English building sites, we have a macho culture that just gets stuck in and then gets a bad back! We now find it normal for kids at school as well as top athletes to warm up before sport, and a few simple stretches could save many days off work.The other thing which I feel is a good policy, but also found frustrating at times, is to all stop work together half an hour before the end of the day. Even if you are only 2 minutes from finishing your joint you have to stop. Then everyone from the head carpenter to the new apprentice work together on sweeping the site, taking care of the tools and leaving everything in good order for the next day. Most accidents and mistakes occur in that last half hour as tired people are rushing to get the job done and it created a great feeling of teamwork all sweeping up together.
After giving a talk to the Carpenters Fellowship and mentioning this I was approached by a chiropractor who told me that if you bend from the waist to 90 degrees you are putting 2 tons of pressure on the vertebrae at the base of the spine and that is before you pick anything up, so it really is worth getting into the habit of bending the knees and keeping back vertical even to lift light objects.