This is an interesting question, to which I have been unable to get a consistent answer, either. I'm interested in the number of steps per minute--used in running training--e.g., the Chi running method, but can't quite pin down what a "step" is. There's an operational definition: whatever a pedometer measures, but some pedometers measure a step as 1 left _or_ right foot, while others measure a step as 1 left _and_ 1 right foot. Modern run training watches--e.g., Polar, Suunto, Garmin, etc.--utilize a shoe-mounted "pod", which is a cheap accelerometer (same technology as is used to set off car airbags) that talks to the watch & tells it the number and "length" of the steps that it takes. Since one usually wears a single "pod" on only one foot, the "cadence" as reported by the watch is the number of steps taken by the left or right foot, depending upon which foot you have mounted the "pod" on. (This usage of "cadence" is at odds with the scientific literature; see below.) By coincidence, this definition of cadence is also appropriate for a bicycle pedaling rhythm, where cadence is consistently measured in rpm -- i.e., the number of times the left (or right) foot is pushed down. Thus, a Polar/Suunto/Garmin watch can report "cadence" equally well when either running or cycling. Another term I've seen used is "leg turnover", also in "steps per minute", but this time the number of steps is the total of left plus right foot steps. I've seen "stride rate" mean the total number of left+right foot steps per minute. When there is TV coverage of a marathon, one of the commentators usually talks about the leg turnover or stride rate of the leaders, which is typically in the range of 180 steps per minute. This clearly means counting the sum of left & right steps. There's also a scientific literature on running & walking, and I think that the following web page provides the definitions from the scientific literature: http://moon.ouhsc.edu/dthompso/gait/knmatics/stride.htm Regarding the measurement of the "mile", wikipedia defines a "pace" as two "steps" (1 left + 1 right): http://en.wikipedia.org/wiki/Mile If a marathoner runs a marathon in 2:11 (=131 minutes=elite world class men's time) at 180 steps per minute (23,580 steps total), this is exactly 900 _steps_ (not paces) per mile, or about 5.87' per step. If he/she runs @ 180 steps per minute, but takes exactly 1000 _steps_ per mile (=5.28' per step), then this marathon time is 2:25:33 (=elite world class women's time). A messenger/courier/scout--e.g., Phidippides--would run about twice as slow as this for very long distances--e.g., 50-100 miles, @ about 5 hour marathon speed, and would take about 1000 _paces_ per mile, which agrees with the basic Roman definition. At 01:20 PM 7/30/2009, James Propp wrote:
Is there a words that means the operation of taking a pair of steps (one with the left foot and one with the right), or the distance travelled during such an operation?
I had hoped that the term "stride" meant this. And indeed, according to at least one website, the stride of a horse is defined as the distance the horse has advanced when each of its legs has returned to its initial position (that is, the distance the horse travels during a full period). But that same site says that a person's stride is defined as the distance the person travels when taking a single step (that is, the distance the person travels during a half-period).
For that matter, is a "lap" equal to one pool-length, or two?
Jim