**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).

1. Average Braking Force – Average force during the braking phase.
2. Average Braking Power – Average power during the braking phase.
3. Average Braking Velocity – Average velocity during the braking phase – always negative.
4. Average Landing Force – Average force during the landing phase.
5. Average Propulsive Force – Average force during the propulsive phase.
6. Average Propulsive Power – Average power generated during the propulsive phase.
7. Average Propulsive Velocity – Average velocity during the propulsive phase – always positive.
8. Average Relative Braking Force – Average braking force as a percentage of system weight – higher is better.
9. Average Relative Braking Power – Average power per kilogram during the braking phase.
10. Average Relative Propulsive Force – Average propulsive force as a percentage of system weight.
11. Average Relative Propulsive Power – Average power per kilogram the subject produced during the propulsive phase.
12. Braking Impulse – Impulse the subject generated during the braking phase.
13. Braking Net Impulse – Impulse of braking phase above system weight (red shaded area of the graph).
14. Braking Phase – The time of the braking phase (seconds).
15. Braking Phase % – The length of the braking phase relative to the entire movement.
16. 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.
17. 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. 
18. 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).
19. 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.
20. 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.
21. L/R Average Braking Force – Asymmetry during the braking phase – positive means left dominance, negative means right dominance.
22. 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.
23. L/R Average Landing Force – Asymmetry during landing – positive means left dominance, negative means right dominance.
24. L/R Average Propulsive Force – Asymmetry during the propulsive phase – positive means left dominance, negative means right dominance.
25. L/R Braking Impulse Index – Left/Right asymmetry of total braking impulse – positive means left dominance, negative means right dominance.
26. L/R Landing Impulse Index – Total impulse asymmetry during landing – positive means left dominance, negative means right dominance.
27. L/R Peak Braking Force – Left/Right asymmetry at moment of peak braking force – positive means left dominance, negative means right dominance.
28. L/R Peak Landing Force – Left/Right asymmetry at moment of peak landing force – positive means left dominance, negative means right dominance.
29. L/R Peak Propulsive Force – Left/Right asymmetry at moment of peak propulsive force – positive means left dominance, negative means right dominance.
30. L/R Propulsive Impulse Index – Left/Right asymmetry of total propulsive impulse – positive means left dominance, negative means right dominance.
31. Peak Braking Force – Peak force during the braking phase.
32. 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.
33. Peak Landing Force – Peak force during the landing phase.
34. Peak Propulsive Force – Peak force during the propulsive phase – commonly used to assess maximal concentric force output.
35. Peak Propulsive Power – Peak power during the propulsive phase – commonly used to assess power output.
36. Peak Relative Braking Force – Peak force during the braking phase relative to system weight.
37. 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.
38. Peak Relative Propulsive Force – Peak force during propulsive phase relative to system weight.
39. Peak Relative Propulsive Power – Peak power per kilogram during the propulsive phase.
40. Peak Velocity – Peak velocity of the athlete during the entire movement.
41. Positive Impulse – Total impulse of the propulsive and braking phase. Impulse is the product of Force x Time.
42. Positive Net Impulse – Total impulse of the propulsive and braking phase above system weight (green and red shaded area of the graph).
43. Propulsive Impulse – Impulse the subject generated during the propulsive phase.
44. Propulsive Net Impulse – Impulse of the propulsive phase above system weight (green shaded area of the graph).
45. Propulsive Phase – Time of the propulsive phase (seconds).
46. Propulsive Phase % – The length of the propulsive phase relative to the entire movement.
47. 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.
48. 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. 
49. Relative Braking Impulse – Impulse per kilogram the subject generated during the braking phase.
50. Relative Braking Net Impulse – Impulse per kilogram the subject generated during the braking phase above system weight.
51. Relative Peak Landing Force – Highest force during landing as a percentage of system weight.
52. Relative Propulsive Impulse – Impulse per kilogram the subject generated during the propulsive phase.
53. Relative Propulsive Net Impulse – Impulse per kilogram the subject generated during the propulsive phase above system weight.
54. 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.
55. System Weight – Average force during the quiet phase (the period of time before the test).
56. Takeoff Velocity – The velocity right before the athlete leaves the force plates – this metric dictates jump height – higher is always better.
57. Time To Takeoff – Time from the initiation of movement (unweighting) to takeoff.
58. 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.
59. Unweighting Phase – Time of the unweighting phase (seconds).
60. Unweighting Phase % – The length of the unweighting phase as a percentage relative to the entire movement.