Squat Jump Metrics

Squat Jump - Timepoints

Start:

Definition: Initiation of the squart jump and start of the concentric phase. 
Calculation: GRFz > bodyweight (N) + 5SD
Units: Frame #

Takeoff:

Definition: End of the concentric phase and start of the flight phase.
Calculation: First frame GRFz < 30N 
Units: Frame #

Ground Contact:

Definition: End of the flight phase and start of the landing phase.
Calculation: First frame GRFz > 30N following takeoff
Units: Frame #

Landing End:

Definition: End of the landing phase
Calculation: Minimum vertical COM Displacement following Ground Contact
Units: Frame #

Squat Jump - KPIs

Bodyweight:

Definition: Average GRFz during weighting phase (i.e., when participant stands motionless on the force platform(s). Also referred to as system weight
Calculation: mean(GRFz[0:500])
Units: Newtons (N)

Mass:

Definition: Mass of the participant (system) in kilograms determined during the weighting phase. 
Calculation: Bodyweight (N) / -9.81 m/s2
Units: Kilograms (kg)

Jump Height:

Definition: Measure of jumping performance. Center of mass displacement of the individual. Calculated based on impulse momentum.
Calculation: Jump height = vtakeoff2(m/s) / 2*gravitational acceleration (m/s/s)
Units: Meters (m), Inches (in)

MRSI:

Definition: Measure of explosive jumping performance. Ratio of Jump Height to Jump Time.
Calculation: Jump Height/ Jump Time
Units: Unitless

Concentric Net Impulse:

Definition: Impulse generated by the individual during the concentric phase independent of bodyweight
Calculation: ∫(Force (N) – Bodyweight(N)) * t(s)
Units: Newton · seconds (N·s)

Momentum:

Definition: Vertical center of mass momentum of the individual at takeoff
Calculation:  mass (kg) * velocitytakeoff (m/s)
Units: Kilogram · meters per second (kg·m/s)

Jump Time:

Definition: Elapsed time between the start of the jump and takeoff 
Calculation: Timetakeoff(s) – Timestart(s)  
Units: Seconds (s)

Flight Time:

Definition: Elapsed time between takeoff and ground contact following takeoff 
Calculation: Timeground contact (s) – Timetakeoff(s)  
Units: Seconds (s)

Squat Jump - Sub-Phase Metrics

Phase Time:

Definition: Temporal duration of the selected phase.
Calculation: ∆phase time(s) 
Units: Seconds (s)

Avg Vel:

Definition: Average center of mass vertical velocity across selected phase.
Calculation: mean COMvelocity(m/s). 
Units: Meters per second (m/s)

Peak Vel:

Definition: Peak negative center of mass vertical velocity within the selected phase.
Calculation: maximum COMvelocity (m/s).
Units: Meters per second (m/s)

Avg Force:

Definition: Average vertical force production during the selected phase. 
Calculation: mean vertical GRFz (N)
Units: Newtons (N)

Avg Force Rel:

Definition: Average vertical force production during the selected phase normalized to participant’s body mass.
Calculation: mean vertical GRFz (N)/ body mass (kg)
Units: Newtons per kilogram (N/kg)

Peak Force:

Definition: Peak vertical force production during the selected phase normalized to participant’s body mass.
Calculation: maximum GRFz (N) during the selected phase 
Units: Newtons (N)

Peak Force Rel:

Definition: Peak vertical force production during the selected phase normalized to participant’s body mass.
Calculation: maximum GRFz (N) during the selected phase / mass (kg)
Units: Newtons per kilogram (N/kg)

Avg RFD:

Definition: Average rate of force development during the selected phase.
Calculation: mean GRFz(N)/ Time (s) across the selected phase
Units: Newtons per second (N/s)

Avg RFD Rel:

Definition: Average rate of force development during the selected phase normalized to participant’s body mass.
Calculation: mean GRFz(N)/ Time (s) across the selected phase / mass(kg) 
Units: Newtons per second per kilogram (N/s/kg)

Peak RFD:

Definition: Peak rate of force development during the selected phase.
Calculation: maximum GRFz(N)/ Time (s) across the selected phase 
Units: Newtons per second (N/s)

Peak RFD Rel:

Definition: Peak rate of force development during the selected phase normalized to body mass.
Calculation: maximum GRFz(N)/ Time (s) across the selected phase divided by mass(kg)
Units: Newtons per second per kilogram (N/s/kg)

Peak Power:

Definition: Peak power production during the selected phase.
Calculation: maximum GRFz(N) * COMvelocity (m/s)
Units: Watts (W)

Peak Power Rel:

Definition: Peak power production during the selected phase normalized to the participant’s body mass.
Calculation: maximum GRFz(N) * COMvelocity (m/s) across the selected phase / mass(kg)
Units: Watts per kilogram (W/kg)

Avg Power:

Definition: Average power production during the selected phase.
Calculation: mean GRFz(N) * COMvelocity (m/s) across the selected phase 
Units: Watts (W)

Avg Power Rel:

Definition: Average power production during the selected phase normalized to the participant’s body mass.
Calculation: mean GRFz(N) * COMvelocity (m/s) across the selected phase /mass(kg)	
Units: Watts per kilogram (W/kg)

Peak Work:

Definition: Peak work production during the selected phase.
Calculation: maximum GRFz(N) * COMdisplacement (m) across the selected phase
Units: Joules(J)

Peak Work Rel:

Definition: Peak power production during the selected phase normalized to the participant’s body mass.
Calculation: maximum GRFz(N) * COMdisplacement (m) across the selected phase / mass (kg)
Units: Joules per kilogram (J/kg)

Avg Work:

Definition: Average power production during the selected phase.
Calculation: mean GRFz(N) * COMdisplacement (m) across the selected 
Units: Joules (J)

Avg Work Rel:

Definition: Average power production during the selected phase.
Calculation: mean GRFz(N) * COMdisplacement (m) across the selected phase / mass (kg)
Units: Joules per kilogram(J/ kg)

Torso Angle:

Definition: Segment angle of the torso at the end of the selected phase. 
Calculation:
Units: Degrees (°)

Hip Flexion Angle L:

Definition: Left hip joint flexion/ extension angle at the end of the selected phase. 
Calculation:
Units: Degrees (°)

Hip Flexion Angle R:

Definition: Right hip flexion/ extension joint angle at the end of the selected phase.
Calculation:
Units: Degrees (°)

Hip Add Angle L:

Definition: Left hip joint adduction/abduction angle at the end of the selected phase.
Calculation:
Units: Degrees (°)

Hip Add Angle R:

Definition: Right hip joint adduction/abduction angle at the end of the selected phase.
Calculation:
Units: Degrees (°)

Hip IR Angle L:

Definition: Left hip joint internal/external rotation angle at the end of the selected phase.
Calculation:
Units: Degrees (°)

Hip IR Angle R:

Definition: Right hip joint internal/external rotation angle at the end of the selected phase.
Calculation:
Units: Degrees (°)

Knee Flexion Angle L:

Definition: Left knee joint flexion/ extension angle at the end of the selected phase.
Calculation:
Units: Degrees (°)

Knee Flexion Angle R:

Definition: Right knee joint flexion/ extension angle at the end of the selected phase.
Calculation:
Units: Degrees (°)

Ankle Flexion Angle L:

Definition: Left ankle joint flexion/ extension angle at the end of the selected phase.
Calculation:
Units: Degrees (°)

Ankle Flexion Angle R:

Definition: Right ankle joint flexion/ extension angle at the end of the selected phase.
Calculation:
Units: Degrees (°)

Squat Jump - Concentric Metrics

Concentric Time:

Definition: Temporal duration of the concentric phase.
Calculation: Takeoff (s) – Braking End (s) 
Units: Seconds (s)

Concentric Avg Vel:

Definition: Average center of mass vertical velocity across the concentric phase.
Calculation: mean (com_velocity)[start:takeoff]
Units: Meters per second (m/s)

Concentric Peak Vel:

Definition: Peak negative center of mass vertical velocity within the concentric phase.
Calculation: max (com_velocity) [start:takeoff]
Units: Meters per second (m/s)

Concentric Avg Force:

Definition: Average vertical force production during the concentric phase. 
Calculation: mean(Force(N))[start:takeoff]
Units: Newtons (N)

Concentric Avg Force Rel:

Definition: Average vertical force production during the concentric phase normalized to participant’s body mass.
Calculation: mean(Force(N))[start:takeoff] / mass (kg)
Units: Newtons per kilogram (N/kg)

Concentric Peak Force:

Definition: Peak vertical force production during the concentric phase normalized to participant’s body mass.
Calculation: max(Force(N))[start:takeoff] 
Units: Newtons (N)

Concentric Peak Force Rel:

Definition: Peak vertical force production during the concentric phase normalized to participant’s body mass.
Calculation: max(Force(N))[takeoff: braking_end] / mass (kg)
Units: Newtons per kilogram (N/kg)

Concentric Avg RFD:

Definition: Average rate of force development during the concentric phase.
Calculation: mean(Force(N)[start:takeoff] / Concentric Time (s)
Units: Newtons per second (N/s)

Concentric Avg RFD Rel:

Definition: Average rate of force development during the concentric phase normalized to participant’s body mass.
Calculation: mean(Force(N)[takeoff: braking_end] / Concentric Time (s))/ mass (kg) 
Units: Newtons per second per kilogram (N/s/kg)

Concentric Peak RFD:

Definition: Peak rate of force development during the concentric phase.
Calculation: max(Force(N)[start:takeoff] / Concentric Time (s)
Units: Newtons per second (N/s)

Concentric Peak RFD Rel:

Definition: Peak rate of force development during the concentric phase normalized to body mass.
Calculation: max(Force(N)[start:takeoff] / Concentric Time (s) / mass(kg).
Units: Newtons per second per kilogram (N/s/kg)

Concentric Peak Power:

Definition: Peak power production during the concentric phase.
Calculation: max(Force(N)[start:takeoff] * com_velocity(m/s)[start:takeoff]
Units: Watts (W)

Concentric Peak Power Rel:

Definition: Peak power production during the concentric phase normalized to the participant’s body mass.
Calculation: max(Force(N)[start:takeoff] * com_velocity(m/s)[start:takeoff]) / mass(kg)
Units: Watts per kilogram (W/kg)

Concentric Avg Power:

Definition: Average power production during the concentric phase.
Calculation: mean(Force(N)[start:takeoff] * com_velocity(m/s)[ start:takeoff])
Units: Watts (W)

Concentric Avg Power Rel:

Definition: Average power production during the concentric phase normalized to the participant’s body mass.
Calculation: mean(Force(N)[start:takeoff] * com_velocity(m/s)[[start:takeoff]) / mass(kg)
Units: Watts per kilogram (W/kg)

Concentric Peak Work:

Definition: Peak work production during the concentric phase.
Calculation: max(Force(N)[start:takeoff] * com_position(m)[[start:takeoff])
Units: Joules(J)

Concentric Peak Work Rel:

Definition: Peak power production during the concentric phase normalized to the participant’s body mass.
Calculation: max(Force(N)[start:takeoff] * com_position(m)[[start:takeoff]) /  mass(kg)
Units: Joules per kilogram (J/kg)

Concentric Avg Work:

Definition: Average power production during the braking phase.
Calculation: mean(Force(N)[start:takeoff] * com_position(m)[[start:takeoff])
Units: Joules (J)

Concentric Avg Work Rel:

Definition: Average power production during the concentric phase.
Calculation: mean(Force(N)[takeoff_end:braking_end] * com_position(m)[[start:takeoff]) / mass(kg)
Units: Joules per kilogram(J/ kg)

Concentric Torso Angle:

Definition: Segment angle of the torso at the end of the concentric phase. 
Calculation:
Units: Degrees (°)

Concentric Hip Flexion Angle L:

Definition: Left hip joint flexion/ extension angle at the end of the concentric phase. 
Calculation:
Units: Degrees (°)

Concentric Hip Flexion Angle R:

Definition: Right hip flexion/ extension joint angle at the end of the concentric phase.
Calculation:
Units: Degrees (°)

Concentric Hip Add Angle L:

Definition: Left hip joint adduction/abduction angle at the end of the concentric phase.
Calculation:
Units: Degrees (°)

Concentric Hip Add Angle R:

Definition: Right hip joint adduction/abduction angle at the end of the concentric phase.
Calculation:
Units: Degrees (°)

Concentric Hip IR Angle L:

Definition: Left hip joint internal/external rotation angle at the end of the concentric phase.
Calculation:
Units: Degrees (°)

Concentric Hip IR Angle R:

Definition: Right hip joint internal/external rotation angle at the end of the concentric phase.
Calculation:
Units: Degrees (°)

Concentric Knee Flexion Angle L:

Definition: Left knee joint flexion/ extension angle at the end of the concentric phase.
Calculation:
Units: Degrees (°)

Concentric Knee Flexion Angle R:

Definition: Right knee joint flexion/ extension angle at the end of the concentric phase.
Calculation:
Units: Degrees (°)

Concentric Ankle Flexion Angle L:

Definition: Left ankle joint flexion/ extension angle at the end of the concentric phase.
Calculation:
Units: Degrees (°)

Concentric Ankle Flexion Angle R:

Definition: Right ankle joint flexion/ extension angle at the end of the concentric phase.
Calculation:
Units: Degrees (°)

Squat Jump - Landing Metrics

Landing Time:

Definition: Temporal duration of the landing phase.
Calculation: Landing End (s) – Ground Contact (s) 
Units: Seconds (s)

Landing Avg Vel:

Definition: Average center of mass vertical velocity across the landing phase.
Calculation: mean (com_velocity)[landing_end:ground_contact]
Units: Meters per second (m/s)

Landing Peak Vel:

Definition: Peak negative center of mass vertical velocity within the landing phase.
Calculation: min (com_velocity) [landing_end:ground_contact]
Units: Meters per second (m/s)

Landing Avg Force:

Definition: Average vertical force production during the landing phase. 
Calculation: mean(Force(N))[ landing_end:ground_contact]
Units: Newtons (N)

Landing Avg Force Rel:

Definition: Average vertical force production during the landing phase normalized to participant’s body mass.
Calculation: mean(Force(N))[ landing_end:ground_contact] / mass (kg)
Units: Newtons per kilogram (N/kg)

Landing Peak Force:

Definition: Peak vertical force production during the landing phase normalized to participant’s body mass.
Calculation: max(Force(N))[landing_end:ground_contact] 
Units: Newtons (N)

Landing Peak Force Rel:

Definition: Peak vertical force production during the landing phase normalized to participant’s body mass.
Calculation: max(Force(N))[ landing_end:ground_contact] / mass (kg)
Units: Newtons per kilogram (N/kg)

Landing Avg RFD:

Definition: Average rate of force development during the landing phase.
Calculation: mean(Force(N)[ landing_end:ground_contact] / Concentric Time (s)
Units: Newtons per second (N/s)

Landing Avg RFD Rel:

Definition: Average rate of force development during the landing phase normalized to participant’s body mass.
Calculation: mean(Force(N)[ landing_end:ground_contact] / Concentric Time (s))/ mass (kg) 
Units: Newtons per second per kilogram (N/s/kg)

Landing Peak RFD:

Definition: Peak rate of force development during the landing phase.
Calculation: max(Force(N)[ landing_end:ground_contact] / Concentric Time (s)
Units: Newtons per second (N/s)

Landing Peak RFD Rel:

Definition: Peak rate of force development during the landing phase normalized to body mass.
Calculation: max(Force(N)[ landing_end:ground_contact] / Concentric Time (s) / mass(kg).
Units: Newtons per second per kilogram (N/s/kg)

Landing Peak Power:

Definition: Peak power production during the landing phase.
Calculation: max(Force(N)[ landing_end:ground_contact] * com_velocity(m/s)[ landing_end:ground_contact]
Units: Watts (W)

Landing Peak Power Rel:

Definition: Peak power production during the landing phase normalized to the participant’s body mass.
Calculation: max(Force(N)[ landing_end:ground_contact] * com_velocity(m/s)[landing_end:ground_contact]) / mass(kg)
Units: Watts per kilogram (W/kg)

Landing Avg Power:

Definition: Average power production during the landing phase.
Calculation: mean(Force(N)[ landing_end:ground_contact] * com_velocity(m/s)[landing_end:ground_contact
Units: Watts (W)

Landing Avg Power Rel:

Definition: Average power production during the landing phase normalized to the participant’s body mass.
Calculation: mean(Force(N)[ landing_end:ground_contact] * com_velocity(m/s)[landing_end:ground_contact]) / mass(kg)
Units: Watts per kilogram (W/kg)

Landing Peak Work:

Definition: Peak work production during the landing phase.
Calculation: max(Force(N)[ landing_end:ground_contact] * com_position(m)[ landing_end:ground_contact])
Units: Joules(J)

Landing Peak Work Rel:

Definition: Peak power production during the landing phase normalized to the participant’s body mass.
Calculation: max(Force(N)[ landing_end:ground_contact] * com_position(m)[ landing_end:ground_contact]) /  mass(kg)
Units: Joules per kilogram (J/kg)

Landing Avg Work:

Definition: Average power production during the landing phase.
Calculation: mean(Force(N)[ landing_end:ground_contact] * com_position(m)[landing_end:ground_contact])
Units: Joules (J)

Landing Avg Work Rel:

Definition: Average power production during the landing phase.
Calculation: mean(Force(N)[ landing_end:ground_contact] * com_position(m)[ landing_end:ground_contact]) / mass(kg)
Units: Joules per kilogram(J/ kg)

Landing Torso Angle:

Definition: Segment angle of the torso at the end of the landing phase. 
Calculation:
Units: Degrees (°)

Landing Hip Flexion Angle L:

Definition: Left hip joint flexion/ extension angle at the end of the landing phase. 
Calculation:
Units: Degrees (°)

Landing Hip Flexion Angle R:

Definition: Right hip flexion/ extension joint angle at the end of the landing phase.
Calculation:
Units: Degrees (°)

Landing Hip Add Angle L:

Definition: Left hip joint adduction/abduction angle at the end of the landing phase.
Calculation:
Units: Degrees (°)

Landing Hip Add Angle R:

Definition: Right hip joint adduction/abduction angle at the end of the landing phase.
Calculation:
Units: Degrees (°)

Landing Hip IR Angle L:

Definition: Left hip joint internal/external rotation angle at the end of the landing phase.
Calculation:
Units: Degrees (°)

Landing Hip IR Angle R:

Definition: Right hip joint internal/external rotation angle at the end of the landing phase.
Calculation:
Units: Degrees (°)

Landing Knee Flexion Angle L:

Definition: Left knee joint flexion/ extension angle at the end of the landing phase.
Calculation:
Units: Degrees (°)

Landing Knee Flexion Angle R:

Definition: Right knee joint flexion/ extension angle at the end of the landing phase.
Calculation:
Units: Degrees (°)

Landing Ankle Flexion Angle L:

Definition: Left ankle joint flexion/ extension angle at the end of the landing phase.
Calculation:
Units: Degrees (°)

Landing Ankle Flexion Angle R:

Definition: Right ankle joint flexion/ extension angle at the end of the landing phase.
Calculation:
Units: Degrees (°)