{HEAD ~ The frequency} of {TAIL ~ manipulation} of the control stick during a representative task, such as word processing, will typically be at least every ten minutes, on average, and may be much more frequently, depending on the particular task and the particular user 
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{ HEAD ~ The frequency } of { TAIL ~ manipulation } of the control stick during a representative task , such as word processing , will typically be at least every ten minutes , on average , and may be much more frequently , depending on the particular task and the particular user
HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH