SpeedCoach Mobile uses the built-in accelerometer in the iPhone (and iPod touch) to accurately measure your stroke rate. But the accelerometer is capable of much more. With it, SpeedCoach Mobile can also calculate metrics that provide insight into the “quality” of your rowing. It does this through two separate metrics – “check” and “bounce”.
The first of these (check) is well understood by rowers and coaches, but can be described and measured in many different ways. After much experimentation, we found that a useful way to think about check is to consider the smoothness of the recovery. During the recovery phase, the rowing shell naturally decelerates. However, irregularities in the natural deceleration can be indicators of flaws in the stroke. Rushing the slide or driving with the legs before the blade is in the water both cause the natural (and gradual) deceleration of the boat to be disrupted.
In SpeedCoach Mobile, the “check” factor is an indicator of the consistency of your deceleration during the recovery phase of the stroke. The lower the number, the smoother your recovery. Higher numbers may indicate one of the flaws mentioned above. Many factors will naturally influence the check factor – boat type, stroke rate, power, water conditions, wind, and so on. It’s best to look at the check factor within the course of a single interval or workout. Comparisons from day to day will be much less meaningful. Within a single interval, you may find it helpful to experiment with your stroke to see what changes can lower the check factor.
To reduce the effects of any single stroke, the check factor is calculated as a running average over your last five strokes. This makes it easier to focus on long-term habits and trends that affect your rowing, rather than focusing on a single bad (or good) stroke.
The bounce factor is easier to describe. Bounce is just a measurement of the energy associated with the vertical displacement of the boat in each stroke, the idea being that vertical motion generally represents wasted effort. High “bounce” numbers may mean that you are lunging at the catch (causing the stern to dip), pulling through too high with the handles during the drive (lifting the hull), or not maintaining good posture at the release (causing the bow to dip). Like the check measurement, bounce is averaged over your last five strokes and comparisons from day to day or boat to boat are discouraged.
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The third annual Kossev Symposium is coming up on November 19-20 in Seattle. Representatives from Performance Phones will be in attendance to demonstrate our application, answer questions, and listen to your feedback. If you plan to attend, please stop by our booth and attend our vendor presentation to learn more about our product and get a sneak-preview of the Windows Phone version currently in development.
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The latest update to SpeedCoach Mobile provides full access to all application settings directly within the app, in a new “Settings” tab. All settings can be changed at any time and will take effect immediately. A new setting in the “advanced” section lets you adjust the threshold for detecting a stroke. This is most useful for some paddling sports where the default settings may require too much power for average users to register a stroke.
This update also includes a couple of bug fixes, including a fix for one rather old bug that could (on some devices) cause the application to auto-pause unexpectedly during a workout. Both the free and paid versions of the application are updated and available as a free upgrade for all current customers.
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SpeedCoach Mobile version 2.2.2 is now available as a free update for all customers. This version adds support for “meters per stroke” on the Row/Paddle screen. The display shows an average over your last 10 strokes (or a countdown until you’ve taken 10 strokes). The distance value is rounded to the nearest 5 cm, and is updated on each stroke.
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The latest update to SpeedCoach Mobile adds support for “meters per stroke”, which many coaches consider an important measure of efficiency. This is computed as a running average over the last 10 strokes and is rounded to the nearest 5 cm. As always, this is provided as a free update for all current customers.
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SpeedCoach Mobile version 2.2.1 is now available as a free update through the iTunes App Store. This is a minor update that fixes a few bugs in exporting, and adds a couple of new data fields (average speed & pace) to the detailed CSV format.
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