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While research has not shown that balance training on a physio ball enhances one's physical performance in any way at all, research has shown that balancing a load on the head certainly can. The research revealing this is intriguing. For those of us who lived in Africa, it was perfectly normal to see the folk there (mainly the women) walking for many kilometres with very heavy loads on their head, while happily chatting away and sharing the news of the day. It is far less strenuous and more comfortable (at least when you grow used to it) to carry loads like that, rather than in the hands or on the back. So, before we had suitcases with little wheels, I always used to put most of my luggage on my head during my overseas travels and walk to my hotel or youth hostel in far greater comfort. Here in the USA, we see endless studies condemning the carrying of heavy school bags in hand or on the back. In Africa, the kids simply put the loads of their heads, kept those wonderfully erect postures and never complained about sore hands, shoulders, backs or arms. Now research is showing that something very interesting is taking place when expert head carriers are balancing and walking with loads on their heads. In reading the extract from the article from Discover journal below, kindly note that head carrying is by no means unique to Kenyans, but is a ubiquitous practice all over the African continent. Maybe, we should be balancing loads on our heads instead of trying to balance on balls in our attempts to enhance balance and locomotion in sporting situations. By the way, the latest issue (July 2001) of Discover also contains an article on the efficiency and value of head carrying in an article on the physics of walking.. The article, by the way, does not mention that longitudinal loading imposed on the head elicits a lengthening response of the spine (sitting on something like a ball actually increases the loading on the lumbar spine - see Chaffin & Andersson "Occupational Biomechanics") and enhances one's posture. Then, of course, this is nothing new to the older members of this group who surely will recall their grandmothers teaching girls of the family better posture by balancing books on their heads. Had they known any better by watching their African counterparts, they would even have indulged in some progressive loading and had the girls walking with more and more books on the head. -------------------------------------- No Skycaps Needed Carl Zimmer <http://www.discover.com/archive/index.html> One of the most startling sights on a first trip to Africa is a common one: women carrying things on their heads. Try to carry a suitcase on your head, and you'll probably bite your tongue in concentration and wave your arms madly for balance. But African women walk for miles with heavy jugs of water or pots of food as if they weren't carrying anything. Energetically speaking, they aren't: researchers have found that the women can carry enormous loads without using any extra energy. They aren't defying any laws of physics, though; they're being good pendulums. <.....non-African researchers couldn't match the carrying capacity of the Kenyan women, at least not with their heads. Heglund and his colleagues had to resort to backpacks and to using old measurements from American Army recruits. Still, the results were extraordinary. The African women could carry a fifth of their weight without burning a single extra calorie; and although larger loads did require more energy, the increase was only half of that needed by the American soldiers. Some women could carry 70 percent of their weight. Funding agencies haven't exactly been desperate for the answer to this riddle, so it's only recently that Heglund has managed to get a step closer to one. While spending a year teaching at the University of Nairobi in 1989, he had some Kenyan women walk across force plates; last year in Belgium he repeated the experiment with European students. Force plates are devices that register the vertical and horizontal forces exerted by a walking animal. A walking human is like a pendulum swinging. When the pendulum is at its lowest point, it is moving fastest, and its energy is almost all kinetic energy of motion. As the pendulum climbs up one side of its arc and is slowed and finally stopped by gravity, that energy isn't all lost; most of it is stored as potential energy and is converted back into kinetic energy when the pendulum starts to fall again. But some of the energy is lost to friction, both in the bearing and between the pendulum and the air. Similarly, when you walk, the kinetic energy of your forward movement turns into potential energy as you rise on one foot and is converted back into kinetic energy as you fall onto the other foot. But with each footfall, only 65 percent of that kinetic energy is carried over into the next step; 35 percent is lost, mostly to internal friction in your leg. That 35 percent has to be made up by your leg muscles, which convert food energy into kinetic energy. The 35 percent rule applies to Kenyan women too--until they start carrying things on their heads. Heglund's force plate readings allowed him to calculate how much energy his subjects were transferring from one step to the next. Without a load, Kenyan women and Europeans both transferred 65 percent. When the Europeans carried loads on their backs, they still lost 35 percent--but now, since they were bearing more weight at the same speed, that 35 percent represented more energy in absolute terms, which they made up by burning more calories. In contrast, the Africans simply became better pendulums. When they carried a fifth of their body weight on their heads, they somehow managed to transfer 75 percent of their energy from one step to the next, losing only 25 percent to friction. With a greater load, one woman reduced her loss to 15 percent. Heglund doesn't know what biomechanical trick the Kenyan women are using--they couldn't tell him--but it must have something to do with carrying things on your head. People who carry things for a living, he notes, from Kenyans to Sherpas, tend to use their heads. "It's just amateurs like us that use suitcases and backpacks," Heglund says. -------------------------- Dr Mel C Siff Denver, USA http://groups.yahoo.com/group/Supertraining/