Terms & Definitions

WKO4 Terms, Abbreviations, and Definitions

Term Name Definition Units
AEPF Average Effective Pedaling Force the average pedaling force applied to the pedal that causes the crank to turn around a complete revolution and contributes to effectively moving the bike forward Newtons (N)
ATL Acute Training Load a rolling short-term (default is seven days) or an athlete's training load TSS per day
Cad Cadence Pedaling revolutions per minute RPM
CIL Chronic Intensity Load an indicator of how the quality of training is progressing through the season; CIL = [(1000* Todays IF) * (1-e^(-1/42)] + {Yesterdays CIL * (e^(-1/42)]  
CPV Circumferential Pedal Velocity how fast the pedal moves around the circle it makes while pedaling IF per day
CTL Chronic Training Load a rolling long-term (default is six weeks) of an athlete's training load TSS per day
EF Efficiency Factor Normalized power (NP) or Normalized Graded Pace (NGP) divided by average heart rate for a workout or a selected portion of a workout  
Fmax Fmax maximal ground reaction force, based on stance time, cadence, and weight Newtons (N) or g force
Form Form, or another term for TSB an athlete's readiness to perform at peak TSS per day
FRC Functional Reserve Capacity the total amount of work that can be done during continuous exercise above FTP (functional threshold power) before fatigue occurs kJ or J/kg
FTP Functional Threshold Power the highest power a rider can maintain in a quasi-steady state without fatiguing Watts
GCT Ground Contact Time the amount of time your foot is in contact with the ground on each stride ms
GPA Gross Power Absorbed the power in a pedal stroke that does NOT contribute to moving the bicycle forward Watts
GPR Gross Power Released the power that contributes to moving the bicycle forward; there is both positive and negative power in each pedal stroke by each leg Watts
HR Heart Rate the number of times your heart beats per minute BPM
IF Intensity Factor the ratio of Normalized Power to Functional Threshold Power Ratio of NP:FTP
KI Kurtotic Index the ratio of the maximum effective pedal force to the average effective pedal force during the power-producing phase of the pedal stroke  
Kleg Kleg the leg spring stiffness constant  
Max Maximum the highest of a collection of numbers N/A
MEPF Maximum Effective Pedaling Force the maximum pedaling force applied to the pedal that causes the crank to turn around a complete revolution and contributes to effectively moving the bike forward  
mFTP Modeled FTP the estimated/modeled FTP supplied by the Power Duration Model in WKO4; mFTP is not directly linked to TSS or PMC metrics and is a guide to help you better establish your sFTP Watts
MMP Mean Max Power the single highest power number achieved for a select time range Watts
NP Normalized Power estimated average power of a workout if it had been completed at a constant power output  
Pa:Hr Pace to Heart Rate the relationship between pace and heart rate  
PDC Power Duration Curve an estimate of the relationship between time to exhaustion and work rate during both anaerobic and aerobic exercise W or W/kg
Pmax Pmax the maximal power that can be generated for a very short period of time over at least a full pedal revolution with both legs W or W/kg
Ramp Ramp Rate the rate at which CTL (chronic training load) is rising or declining TSS per day
RE Running Effectiveness the ratio of speed to power; the inverse of the effective horizontal retarding force that a runner must overcome to achieve a particular speed kg per Newton
RPM Rotations Per Minute used with cadence RPM
sFTP Set FTP the user-defined and user-set FTP in WKO4; the base calculation for all TSS and PMC metrics Watts
SLR Simple Linear Regression a method of predicting scores on one variable based on the scores on a second variable; produces a line representing the best-fitting straight line through the predicted scores N/A
Stamina Stamina a measure of resistance to fatigue during prolonged duration, moderate intensity (i.e., sub-FTP) exercise % of Max (0-100%)
TiZ Time in Zone cumulative (but not necessarily consecutive) time spent in a specific training zone H:M:S (time)
TSB Training Stress Balance intersection of CTL (chronic training load) and ATL (acute training load); an athlete's readiness to perform at peak TSS per day
TSS Training Stress Score the total workload of a ride as a function of duration and intensity TSS
TTE Time to Exhaustion the maximum duration for which a power equal to FTP can be maintained H:M:S (time)
VAM Velocita Ascensionale Media average ascent speed (the acronym and term are Italian) m/h
Vertical oscillation Vertical oscillation how much your center-of-mass bounces or travels up-and-down while running cm
VI Variability Index the measure of how smooth or evenly paced an athlete's power output was during a race or workout  
WAC Williams Allen Coggan "Against World Class" - measured power duration curve against world class curve
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