***Below are the metrics as defined by and used by Hawkin Dynamics in Countermovement Jump analyses.**

**Unweighting Phase (Yellow) – Braking Phase (Red) – Propulsive Phase (Green)**

**System Weight is the 1-second period prior to the athlete initiating movement. It is important that the athlete remains as still as possible during this time for an accurate measurement of weight. It is a combination of the athlete’s bodyweight, gravity, and any additional load (i.e. dumbbells, vest).**

**Average Braking Force**– Average force during the braking phase.**Average Braking Power**– Average power during the braking phase.**Average Braking Velocity**– Average velocity during the braking phase – always negative.**Average Landing Force**– Average force during the landing phase.**Average Propulsive Force**– Average force during the propulsive phase.**Average Propulsive Power**– Average power generated during the propulsive phase.**Average Propulsive Velocity**– Average velocity during the propulsive phase – always positive.**Average Relative Braking Force**– Average braking force as a percentage of system weight – higher is better.**Average Relative Braking Power**– Average power per kilogram during the braking phase.**Average Relative Propulsive Force**– Average propulsive force as a percentage of system weight.**Average Relative Propulsive Power**– Average power per kilogram the subject produced during the propulsive phase.**Braking Impulse**– Impulse the subject generated during the braking phase.**Braking Net Impulse**– Impulse of braking phase above system weight (red shaded area of the graph).**Braking Phase**– The time of the braking phase (seconds).**Braking Phase %**– The length of the braking phase relative to the entire movement.**Braking Rate of Force Development (RFD)**– The rate of force development during the braking phase – higher is typically better for explosive athletes. Can be highly variable between tests.**Countermovement Depth**– The distance the athlete’s center of mass travelled downwards during the countermovement. Can be useful in analyzing changes in jumping strategy overtime.**Flight Time**– Time spent in the air, begins at take-off (athlete leaves the force plate) and ends upon landing (athlete comes back into contact with the force plate).**Impulse Ratio**– The ratio of propulsive net impulse to braking net impulse – useful to understanding how an athlete utilizes the braking phase and the transition from braking to propulsive.**Landing Stiffness**– The force at the lowest point after landing divided by the depth (in meters) at the lowest point – higher means more force is generated with less movement, resulting in higher landing stiffness.**L/R Average Braking Force**– Asymmetry during the braking phase – positive means left dominance, negative means right dominance.**L/R Average Braking Rate of Force Development (RFD)**– Asymmetry of each individual limb’s Rate of Force Development –*positive*means left dominance,*negative*means right dominance.**L/R Average Landing Force**– Asymmetry during landing –*positive*means left dominance,*negative*means right dominance.**L/R Average Propulsive Force**– Asymmetry during the propulsive phase –*positive*means left dominance,*negative*means right dominance.**L/R Braking Impulse Index**– Left/Right asymmetry of total braking impulse –*positive*means left dominance,*negative*means right dominance.**L/R Landing Impulse Index**– Total impulse asymmetry during landing –*positive*means left dominance,*negative*means right dominance.**L/R Peak Braking Force**– Left/Right asymmetry at moment of peak braking force –*positive*means left dominance,*negative*means right dominance.**L/R Peak Landing Force**– Left/Right asymmetry at moment of peak landing force –*positive*means left dominance,*negative*means right dominance.**L/R Peak Propulsive Force**– Left/Right asymmetry at moment of peak propulsive force –*positive*means left dominance,*negative*means right dominance.**L/R Propulsive Impulse Index**– Left/Right asymmetry of total propulsive impulse –*positive*means left dominance,*negative*means right dominance.**Peak Braking Force**– Peak force during the braking phase.**Peak Braking Power**– Peak (lowest in this case) power during the braking phase – this will always be negative because the athlete is moving downward with negative velocity.**Peak Landing Force**– Peak force during the landing phase.**Peak Propulsive Force**– Peak force during the propulsive phase – commonly used to assess maximal concentric force output.**Peak Propulsive Power**– Peak power during the propulsive phase – commonly used to assess power output.**Peak Relative Braking Force**– Peak force during the braking phase relative to system weight.**Peak Relative Braking Power**– Peak (lowest) power per kilogram during the braking phase – this will always be negative because the athlete is moving downward with negative velocity.**Peak Relative Propulsive Force**– Peak force during propulsive phase relative to system weight.**Peak Relative Propulsive Power**– Peak power per kilogram during the propulsive phase.**Peak Velocity**– Peak velocity of the athlete during the entire movement.**Positive Impulse**– Total impulse of the propulsive and braking phase. Impulse is the product of Force x Time.**Positive Net Impulse**– Total impulse of the propulsive and braking phase above system weight (green and red shaded area of the graph).**Propulsive Impulse**– Impulse the subject generated during the propulsive phase.**Propulsive Net Impulse**– Impulse of the propulsive phase above system weight (green shaded area of the graph).**Propulsive Phase**– Time of the propulsive phase (seconds).**Propulsive Phase %**– The length of the propulsive phase relative to the entire movement.**Reactive Strength Index (RSI)**– Flight Time divided by contact time (beginning of movement to flight) – useful to assess quickness and reactivity ( Flight Time / Contact Time = RSI ) *not to be mistaken with modified RSI.**Modified RSI (mRSI)**– Jump Height (in meters) divided by contact time (beginning of movement to take-off). Also useful to assessment of quickness and reactivity in athletes. There is some good quality research on mRSI as an ideal metric to use for general assessments of athletes.**Relative Braking Impulse**– Impulse per kilogram the subject generated during the braking phase.**Relative Braking Net Impulse**– Impulse per kilogram the subject generated during the braking phase above system weight.**Relative Peak Landing Force**– Highest force during landing as a percentage of system weight.**Relative Propulsive Impulse**– Impulse per kilogram the subject generated during the propulsive phase.**Relative Propulsive Net Impulse**– Impulse per kilogram the subject generated during the propulsive phase above system weight.**Stiffness**– The force at the lowest point in the movement divided by the depth (in meters) at the lowest point (see countermovement depth) – higher means more force is generated with less movement, resulting in higher stiffness.**System Weight**– Average force during the quiet phase (the period of time before the test).**Takeoff Velocity**– The velocity right before the athlete leaves the force plates – this metric dictates jump height – higher is always better.**Time To Takeoff**– Time from the initiation of movement (unweighting) to takeoff.**Time To Stabilization**– Time to stabilize after landing – starts when the athlete lands back onto the force plates after flight and ends when system weight returns stabilizes back to normal.**Unweighting Phase**– Time of the unweighting phase (seconds).**Unweighting Phase %**– The length of the unweighting phase as a percentage relative to the entire movement.