In the STATSports Sonra software, data from any Apex unit can be downloaded in “GK Mode”. Once downloaded in GK Mode, goalkeeper specific metrics will be calculated for the relevant session, in addition to the full 250+ metrics available in a standard download. Users can specify for selected players to download as GK automatically or turn off GK features for certain training days where a standard download is most appropriate (e.g. aerobic fitness session).
GK sessions will be indicated by a net icon on the session selector and will display GK metrics by default in dashboards. Furthermore, all GK metrics are available in Sonra’s Custom Metric Calculator, meaning practitioners can take the existing GK metrics and create their own bespoke metrics.
The GK metrics available in Sonra are; Total Dives, Dives Left, Dives Right, Average GK Power, GK Load, Return to Feet, Average Time Since Last Dive and Average Dive Impact.
Dives
Dives are calculated from the Apex devices inertial sensors to identify when a goalkeeper has performed a dive and determines the direction, either left or right. This can be used to display an absolute count of the Total Dives performed, or the number of dives left and right, either throughout a range of drills in a session, a range of training days throughout the week, or to compare outputs from multiple goalkeepers in a single session. This information can be useful in describing not only the load incurred across training days, but also at the individual drill level to inform session design. These can be viewed in customisable dashboards like all other metrics.
Average Dive Impact
Average dive impact is the average impact value recorded across all detected dive events. Impacts can be viewed per dive, or as an average across all dives.
Average GK Power
Average GK Power is based on the principle of mechanical power and is reported during dive events. The Average GK power per dive indicates the intensity of individual dives, while also allowing users to estimate the rate of fatigue throughout a session or drill. Average GK Power can be viewed per individual dive event, or for selected time periods/drills and full session averages.
Average GK Power could be used to assess the output in a maximal effort in either direction to highlight any asymmetries which may exist. However, it should be considered that the dive response of a goalkeeper is proportionate to the stimulus they are exposed to (i.e. shot/serve), so a decrease in output could simply be due to the demands of the drill.
GK Load
GK Load is an external load score calculated during goalkeeper specific events only, effectively quantifying the loading experienced during all dives performed within a session. GK Load is calculated based on several key factors during the dive, such as the peak acceleration leading into the dive, impact at ground contact and the return to feet effort post impact. This value can be used as cumulative loading score per session and should monitored at an individual level.
Return to Feet
Return to Feet is simply the time taken to return to an upright position following ground contact and can be viewed per individual dive effort. This can be used as a performance marker for dive recovery.
Average Time Since Last Dive
Average Time Since Last Dive takes the time period selected by the user to give an indication of the frequency dives are occurring within a particular session or drill to indicate the dive response various activities will have on a goalkeeper. This value is reported in seconds.