Bests & Worsts Reviews from Amazon

After having little success using a $250 Timex Bodylink GPS watch (see review) in Manhattan, I decided to try this $15 pedometer. At first I was quite skeptical. However my tests showed the Sportline 340 Pedometer having astounding repeatability (better than 1%) and accuracy. Most pedometers, including this one, are very basic instruments. Inside the device, there is a balanced weight that is very sensitive to vertical motion. When clipped to your belt, it increments the counter as you step driven by the translation of one side of your waist. In order to test and calibrate the Sportline 340 Pedometer, I walked a very straight stretch of six Manhattan blocks. In the first group of tests, there were few sidewalk obstacles and minimal pedestrian traffic that impeded my movements. In order to be moderately scientific, I was certain to start and stop on the proper side of the street so the distance included exactly six stretches of cross street and six stretches of sidewalk. After four trips of walking the same path, my step counter showed an amazingly small range of 588 to 594 steps. When one considers the variables imposed, such as not always being able to walk completely straight, the results are even more impressive. As you can see from the data below, the accuracy was quite amazing. The difference from the mean never exceeded 1%. Given the simplicity of the pedometer, I didn't expect this level of repeatability. Moreover, I didn't expect my stride length to be so uniform. My hypothesis was that the exceptional accuracy may have been fostered, in part, by the shoes I was wearing. The Kenneth Cole Building Block shoes (see review) have very heavy soles and large heals. These may insure that the impact is harsh enough to always trigger the movement of the weight. On a second grouping of tests, I walked precisely the same path wearing my New Balance 620 cross trainers (see review). The conditions were not the same as the first group due to far more pedestrian traffic and other obstacles, which made it very difficult to walk in a straight line. In fact, one test had to be scrapped as I was nearly run over by a taxi. As you can see below, the second group produced a step count about 2% greater than the first group. Yet this was probably due to the unavoidable path changes. Considering that the pedometer is only calibrated in whole inches, the accuracy truly limited by the precision of the calibration settings. This means there is no difference in the two calibrations as both stride lengths would round to 32 inches. For the price, the Sportline 340 pedometer is an excellent piece of fitness equipment. If you enjoy low-impact exercise by walking, consider this device as an excellent tool for tracking your efforts. Pros Inexpensive Light Accurate Cons Lack of speed, time or other measurements Requires user to look down while tilting the device upward Possible inaccuracy caused by movement other than walking Needs greater calibration precision TEST DATA Experimental conditions: 1) NYC Avenue N/S: Amsterdam from 73rd to 79th 2) Measured distance on MS Streets and Trips 2005: .301 miles/1589 feet 3) Calculated distance based on NYC grid: .300 miles/1584 feet Group1 - Wearing Kenneth Cole Building Block Shoes ________steps____diff from mean____calculated stride length Test 1____592____0.04%________32.22 Test 2____593____0.21%________32.16 Test 3____594____0.38%________32.11 Test 4____588____-0.63%________32.43 Average____591.8____________32.23 Std Dev____2.6 Group2 - Wearing New Balance 620 Cross trainers ________steps____diff from mean____calculated stride length Test 1____597____-0.75%________31.95 Test 2____614____2.08%________31.06 Test 3____595____-1.08%________32.05 Test 4____600____-0.25%________31.79 Average____601.5____________31.71 Std Dev____8.6