Appendix C - Event definitions

Event detection algorithm can be set on session level, see 'Event mode'. Default event detection algorithm is set to 'Force Plates'. Other options are 'No Force Data (Automatic)' which is using kinematics data and 'Manual' where user sets events manually in QTM. When event mode is set to 'Force Plates', events are always detected from ground reaction forces. 'Manual' event mode is applied only if no GRF is found and is suitable for situations when 'No Force Data (Automatic)' mode fails to detect event correctly.

Kinematics graphs are plotted between PlotStart and PlotEnd events. Kinetics graphs are potted between PlotStartForce and PlotEndForce events. When force plates are used for event detection ON and OFF events are used to define PlotStart and Plot End. Without force plates PlotStart and PlotEnd events are based on foot proximal end velocity and approximately correspond to force based ON and OFF events.

When manual event mode is used, events must be named LON, LOFF, RON, ROFF for all tasks.

Force based events

By default it is assumed that force plates exist and Event mode is set to 'Force Plates'. Automatic event detection is applied that give ON and OFF events based on foot contact to force plate.

Acceleration

LON/RON/LOFF/ROFF events are created based on ground reaction data. It is recommended that only first step hits a plate.

Balance

PlotStart is a first frame.

PlotEnd is a last frame.

Change of direction

LON/RON/LOFF/ROFF events are created based on ground reaction data. It is recommended that there is only contact with the force plate is when direction of movement occurs.

Counter-movemment Jump

LON/RON/LOFF/ROFF events are created based on ground reaction data

TouchDown - either LON or RON or mean of LON and RON, if both events are available

TakeOff - either LOFF or ROFF or mean of LOFF and ROFF, if both events are available

Eccentric_end - calculated as peak body COM vertical velocity. COM vertical velocity calculated from vertical force using F = m*a formula.

Cutting

It is assumed that only one foot contact with force plate is executed during cutting manoeuvre

TouchDown - first instance of ascending crossing of 0.1 on vertical component of ground reaction force

TakeOff - as first instance after TouchDown of descending crossing of 0.1 on vertical component of ground reaction force

Weight Acceptance (END_WA) - first minimum of vertical ground reaction force between TouchDown and TakeOff

Maximum knee flexion (Max_knee_flex) - global minimum of knee flexion between TouchDown and TakeOff

Virtual_gate_start and Virtual_gait_end - set in settings.php as the shortest distance of pelvis origin at the event to pelvis origin at foot contact with force plate.

Drop Jump

LON/RON/LOFF/ROFF events are created based on ground reaction data.

TouchDown_L - first instance of LON

TouchDown_R - first instance of RON

TakeOff_L - first instance of LOFF

TakeOff_R - first instance of ROFF

Landing_L - second instance of LON

Landing_R - second instance of RON

TouchDown - first instance of ascending crossing of 200 on vertical force

TakeOff - first instance after TouchDown of descending crossing of 20 on vertical force

Landing - first instance after TakeOff of ascending crossing of 200 on vertical force

Eccentric_end - calculated from body COM vertical velocity. If cannot be calculated from body COM, lowest point of pelvis vertical displacement is used instead.

Gait

LON/RON/LOFF/ROFF events are created based on ground reaction data.

Lateral Leap

LON/RON/LOFF/ROFF events are created based on ground reaction data

Power Jump

LON/RON/LOFF/ROFF events are created based on ground reaction data.

Running

LON/RON/LOFF/ROFF events are created based on ground reaction data.

Side Hop

LON/RON/LOFF/ROFF events are created based on ground reaction data

Single-leg Cross Drop Landing

TouchDown - first instance of ascending crossing of 200 on vertical force.

PlotEnd - as defined by $SLL_duration in settings.php.

Single-leg Jump

TouchDown - first instance of ascending crossing of 200 on vertical force

TakeOff - last maximum on vertical component of pelvis COG velocity before TouchDown

Weight Acceptance (END_WA) - first minimum of vertical ground reaction force between TouchDown and TakeOff

Maximum knee flexion (Max_knee_flex) - global minimum of knee flexion between TouchDown and TakeOff

Single-leg Landing

The same as Single-leg Jump

PlotEnd - as defined by $SLL_duration in settings.php.

Squatting

TOP - zero crossing of vertical component of pelvis COG velocity

Tapping

LON/RON/LOFF/ROFF events are created based on ground reaction data.

Kinematics based events

When force plates are not available it is possible to derive events from kinematics data by setting Event mode to 'No Force Data (Automatic)'.

Acceleration

LON/RON - minimum on AP component of foot distal end velocity

LOFF/ROFF - maximum on vertical component of foot distal end velocity

Balance

PlotStart is a first frame.

PlotEnd is a last frame.

Change of direction

LON/RON - minimum on vertical component of foot distal end velocity

LOFF/ROFF - onset of ML component of foot distal end velocity after pelvis stop (change of direction)

Counter-movemment Jump

LON/RON - global minimum of vertical component of pelvis COG velocity

LOFF/ROFF - last onset of AP component of foot distal end velocity before global maximum on same signal

TakeOff - mean of LOFF and ROFF

TouchDown - mean of LON and RON

Cutting

TouchDown - last minimum on vertical component of foot distal end velocity before first minimum on AP component of the same signal

TakeOff - onset on vertical component of foot distal end velocity after first minimum on AP component of the same signal

Drop Jump

TakeOff_L/TakeOff_R - global maximum on vertical component of foot distal end velocity

TouchDown_L/TouchDown_R - last minimum on vertical component of foot distal end velocity before TakeOff_L/TakeOff_R

Landing_L/Landing_R - first minimum on vertical component of foot distal end velocity after TakeOff_L/TakeOff_R

TakeOff - same as Takeoff_L

TouchDown - same as TouchDown_L

Landing - same as Landing_L

Gait

Using Zeni (2008) based approach

LHS/RHS - maximum on AP component of heel to pelvis distance

LTO/RTO - minimum on AP component of heel to pelvis distance

LON/RON - same as LHS/RHS

LOFF/ROFF - same as LTO/RTO

Lateral Leap

TouchDown - minimum on vertical component of foot distal end velocity

TakeOff - onset of ML component of foot distal end velocity

Power Jump

TouchDown - ascending zero crossing of vertical component of foot distal end velocity

TakeOff - ascending zero crossing of vertical component of foot distal end velocity

Running

The same as Gait

Side Hop

LON/RON - minimum on vertical component of foot distal end velocity

LOFF/ROFF - global maximum on vertical component of foot distal end velocity between ON events

Single-leg Cross Drop Landing

TouchDown - minimum on vertical component of foot distal end velocity

PlotEnd - as defined by $SLL_duration in settings.php.

Single-leg Jump

TouchDown - global minimum on vertical component of foot distal end velocity

TakeOff - last maximum on vertical component of pelvis COG velocity before TouchDown

Maximum knee flexion (Max_knee_flex) - global minimum of knee flexion between TouchDown and TakeOff

Single-leg Landing

The same as Single-leg Jump

Squatting

TOP - zero crossing of vertical component of pelvis COG velocity

Tapping

LON/RON - minimum on vertical component of foot distal end velocity

LOFF/ROFF - global maximum on vertical component of foot distal end velocity between ON events