Concept2 ergometers display pace, watts, and calories per hour on the performance monitor (PM) during a workout. Below is an interactive chart that displays each of these, as well as speed, to help in planning and performing your workouts. Mouse over or tap to see metrics at a given pace.

Below are descriptions of the terms and math involved in calculating the verious metrics in the above graph. Reading these is not necessary.

Note: formulas are presented in MathML, currently unsupported in the Google Chrome browser.

## Split

Pace is the length of time in seconds to cover a set distance. In the chart above, it is shown on the X axis, starting at 3:00 and going down to 1:00.

The PM shows split, which is pace over 500m for RowErg and SkiErg, and 1000m for BikeErg. It is the basis for other metrics in the chart above.

${\mathrm{split}}_{\mathrm{seconds}}={\mathrm{split distance}}_{\mathrm{metres}}×\left(\frac{{\mathrm{work time}}_{\mathrm{seconds}}}{{\mathrm{work distance}}_{\mathrm{metres}}}\right)$

## Power

The PM shows power (P) each stroke, measured in watts.

${P}_{watts}=\frac{2.8}{{\left(\frac{{\mathrm{split}}_{\mathrm{seconds}}}{{\mathrm{500}}_{\mathrm{metres}}}\right)}^{3}}$

## Calories per hour

The PM shows calories per hour. This is roughly how many calories a 79.5kg individual would “burn” over an hour based on the last recorded stroke variables of power (P) and time (t).

First we calculate the mechanical work (W) in kilojoules:

${W}_{\mathrm{kJ}}=\frac{\left({P}_{\mathrm{watts}}×{t}_{\mathrm{seconds}}\right)}{1000}$

Then we determine calories per hour (E) based on this mechanical work W and time t of the stroke:

${E}_{\mathrm{calories per hour}}=\frac{\left(4×{W}_{\mathrm{kJ}}+0.35×{t}_{\mathrm{seconds}}\right)}{4.2}$

(See The Physics of Ergometers section 11 for information on the constants)

## Speed

Speed is not displayed by the PM. It is calculated by scaling the pace across an entire hour, and is measured in kilometres per hour (kph).

${\mathrm{Speed}}_{\mathrm{kph}}=\left(\frac{{\mathrm{split distance}}_{\mathrm{metres}}}{{\mathrm{Pace}}_{\mathrm{seconds}}}\right)×\left(\frac{{60}_{\mathrm{minutes}}×{60}_{\mathrm{seconds}}}{{\mathrm{1000}}_{\mathrm{metres}}}\right)$

Note: speed is calculated and shown here to provide rough equivalency between Concept2 ergometers and other machines in terms of distance and time. This does not equate effort nor energy expenditure.

## Source

The above formulas and notes are summarised from original works by Concept2 and Anu Dudhia. More detailed information can be found by following the links below.

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