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.

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

## Power

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

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

## 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:

${W}_{\mathrm{kJ}}=\frac{\left({P}_{\mathrm{watts}}\times {t}_{\mathrm{seconds}}\right)}{1000}$
Then we determine calories per hour (*E*) based on this mechanical
work *W* and time *t* of the stroke:

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

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

Find me here.