Impulse describes the total force applied over a selected period of time. In force-time testing, impulse is calculated as the area under the force-time curve. In simple terms, it reflects both how much force a client produces and how long that force is applied.
Impulse is commonly used in force plate testing, jump testing, isometric strength testing, sprint-related testing, push-pull testing, load cell testing and performance monitoring. It helps professionals understand force application beyond peak force alone.
A high impulse generally means the client applied more total force across the selected phase or time window. A low impulse generally means less total force was applied across that same phase or time window. However, high or low impulse should not be interpreted as automatically good or bad. The meaning depends on the test, movement phase, time window, body mass, symptoms, task goal and related metrics.
Systematic review evidence shows that isometric force-time characteristics, including impulse, can provide insight into force production capability and may relate to dynamic performance, although the strength of these relationships varies by test and population.
Peak force tells you the highest force a client produces. Impulse tells you something different: how much force was applied across time.
This matters because most human movement is time-dependent. A client may reach a high force, but if it happens too late or only for a very short moment, it may not meaningfully support the task. Another client may produce a lower peak force but apply useful force for longer, resulting in a higher impulse.
Impulse helps answer:
“How much force did the client apply across the available time?”
This can be useful in jumping, sprinting, change of direction, stepping, balance recovery, pushing, pulling and isometric strength testing. In Measurz, impulse can help professionals monitor force application strategy, compare sides, track progress and explain client performance using more than a single peak value.
Impulse should not be used as a diagnosis, clearance tool or standalone performance decision. It should be interpreted with peak force, rate of force development, time to peak, symptoms, movement quality, task demands and the client’s baseline.
Metric name: Impulse
What it means: Total force applied over a selected period of time
Simple explanation: Force × time
Graph explanation: Area under the force-time curve
Common units: Newton-seconds, or N·s
Other possible device units: kg·s, lb·s, N·s/kg, body weight seconds, or device-specific units
Common testing methods: Force plates, load cells, dynamometers, Muscle Meter-style devices, jump testing systems and push-pull devices
Best use: Understanding force application over time, side-to-side comparison, jump strategy, baseline tracking, fatigue monitoring and progress tracking
High impulse: Usually indicates greater total force-time output across the selected phase or window
Low impulse: Usually indicates lower total force-time output across the selected phase or window
Major limitation: Impulse cannot be interpreted properly without knowing the test, time window, phase and calculation method
Impulse is the total force applied across time.
In force-time testing, impulse is calculated from the area under the force-time curve. A larger area under the curve means a greater impulse.
Impulse can increase because:
The client applies more force
The client applies force for longer
The client applies force more consistently
The client changes movement strategy
The selected time window is longer
This is important because the same impulse can be achieved in different ways. For example, a client may use a high-force, short-duration strategy, while another uses a lower-force, longer-duration strategy. Countermovement jump research has shown that force-time curve shape can reveal different movement strategies even when the overall performance output appears similar.
Impulse is usually measured using a device that records force over time, such as:
Force plates
Load cells
Fixed dynamometry systems
Cable-based force devices
Jump testing platforms
Push-pull devices
Isometric strength testing systems
Impulse is commonly recorded in:
N·s: Newton-seconds
kg·s: kilogram-seconds, when the device displays force in kilograms
lb·s: pound-seconds, when the device displays force in pounds
N·s/kg: impulse normalised to body mass
BW·s: body weight seconds, sometimes used in jump testing contexts
The safest approach is to record the exact unit displayed by the device and use the same device, unit, test protocol, time window and calculation method for retesting.
Impulse is used because performance is often about more than the highest force number.
For example:
A jump requires force to be applied during a limited push-off phase.
A sprint step requires force to be applied quickly within a short ground contact.
A balance correction requires force to be generated and applied within a useful time window.
A push or pull task may require force to be sustained.
A repeated effort test may show whether impulse declines with fatigue.
In isometric testing, impulse is commonly examined alongside peak force and rate of force development. A systematic review of multi-joint isometric tests reported that force-time characteristics such as peak force, RFD and impulse can show small to very large relationships with dynamic performance, depending on the test and performance task.
Impulse measures force contribution across a selected time period.
It may provide context about:
Total force application
Ability to sustain force
Early force contribution
Late force contribution
Braking strategy
Propulsive strategy
Side-to-side contribution
Movement strategy
Fatigue-related decline
Force-time adaptation over repeated testing
Impulse does not directly measure:
Peak strength
Power
Speed
Skill
Tissue status
Pain source
Movement quality
Readiness to return to sport
Overall fitness
Why the result changed
Impulse is valuable because it adds context, not because it explains everything on its own.
Impulse must be interpreted based on the phase or time window measured.
Total impulse is the force-time output across the full selected task or contraction.
This may be useful during:
Isometric strength testing
Sustained push or pull tests
Repeated effort testing
Strength-endurance style tasks
Early impulse measures the force applied in the early part of a contraction, such as 0–50 ms, 0–100 ms or 0–200 ms.
This is more relevant when rapid force application matters, such as sprinting, jumping, cutting or balance recovery.
Braking impulse is commonly used in countermovement jump analysis. It reflects the force-time contribution during the braking or deceleration portion of the movement.
This may help professionals understand how the client absorbs and redirects force before propulsion.
Propulsive impulse reflects the force-time contribution during the upward propulsion phase of a jump or similar movement.
Relative net vertical impulse has been shown to be strongly related to jump height in static and countermovement jump conditions, supporting the idea that vertical jumping depends on the ability to generate sufficient impulse relative to body mass.
Net impulse usually refers to impulse after body weight or system weight is accounted for, depending on the device and calculation method.
This is especially important in force plate testing because body weight contributes to the vertical force signal.
This expresses impulse relative to body mass, commonly as:
N·s/kg
BW·s
Similar body-mass-normalised outputs
This can help compare clients of different sizes, especially in bodyweight tasks such as jumping, stepping and sprinting.
A high impulse usually means the client applied more total force over the selected time window or movement phase.
This may suggest:
Greater total force-time output
Better force sustainment
Stronger propulsive contribution
More effective braking or deceleration contribution
Improved jump or push-off strategy
Better ability to apply force across the available time
Improved performance in tasks where force must be applied over a longer phase
However, high impulse is not automatically better.
A high impulse can occur because the client:
Applied more force
Took longer to apply force
Used a deeper countermovement
Increased movement duration
Changed technique
Produced more braking force
Spent more time in the propulsive phase
This matters because some tasks require impulse to be produced quickly. A client may create high impulse by taking more time, but that may not be useful for a sport task with short contact times.
High impulse may be a positive finding when:
It occurs in the correct movement phase
It supports the client’s task goal
It improves without excessive slowing
It aligns with better jump, sprint, strength or function outcomes
Symptoms are stable or improved
Movement quality remains acceptable
High impulse may need more context when:
The movement became slower
The client used a much deeper or longer strategy
Braking impulse increased without improved performance
The result changed because of altered technique
The score is high only because body mass is high
A safer Measurz-style interpretation is:
“Impulse was higher in this test, suggesting greater force-time output across the selected phase. This should be interpreted with movement duration, technique, peak force, RFD, symptoms and task goals.”
A low impulse usually means the client applied less total force over the selected time window or movement phase.
This may suggest:
Lower force output
Shorter force application time
Reduced ability to sustain force
Poorer propulsive contribution
Reduced braking or deceleration contribution
Fatigue
Pain or symptom limitation
Hesitation or guarding
Lower confidence
Reduced intent
Different movement strategy
Poor familiarisation
Low impulse does not automatically mean “weak”. It only tells you that the force-time output was lower in that specific test window.
Low impulse may be meaningful when:
It is lower than the client’s baseline
It is lower on one side compared with the other
It occurs with reduced performance
It occurs with increased pain, fatigue or apprehension
It appears consistently across repeated trials
It aligns with related findings such as lower peak force or slower RFD
Low impulse may be less concerning when:
It reflects a deliberate faster strategy
It occurs in a phase that is not central to the task goal
It is caused by a shorter movement duration but performance is unchanged or improved
It is within normal day-to-day variation
The client is unfamiliar with the test
A safer Measurz-style interpretation is:
“Impulse was lower in this test today, which may indicate reduced force-time output across the measured phase. This should be interpreted with baseline, symptoms, movement strategy, peak force and related performance measures.”
Impulse and peak force are related, but they answer different questions.
Peak force asks:
“What was the highest force reached?”
Impulse asks:
“How much force was applied across the selected time period?”
A client can have:
High peak force and low impulse
Low peak force and high impulse
High early impulse and low total impulse
High total impulse and slow force application
This is why impulse can add important context when peak force alone does not explain the client’s performance.
Impulse and Rate of Force Development, or RFD, also tell different stories.
RFD asks:
“How quickly did force rise?”
Impulse asks:
“How much force was applied over time?”
A client may have high RFD but low impulse if they produce force quickly but cannot sustain it. Another client may have lower RFD but higher impulse if they produce force more gradually and apply it for longer.
Both can be useful when the task requires force to be produced quickly and applied effectively.
When reviewing impulse, look for:
The exact impulse type
The time window
The movement phase
Units
Whether it is absolute or body-mass-normalised
Side-to-side difference
Change from baseline
Related peak force
Related RFD
Related time to peak
Movement duration
Symptoms or pain
Trial consistency
Movement strategy
Whether fatigue affected later trials
The most important question is:
“Impulse across what?”
Impulse without phase, time window and method is incomplete.
No. There is no single universal normative impulse value that applies across all clients, devices, tests and populations.
Impulse is too protocol-dependent. Values change depending on:
Test type
Device
Sampling frequency
Filtering
Start and end thresholds
Movement phase
Time window
Body mass
Task instruction
Whether the value is net, total, braking, propulsive, early or late impulse
Whether the value is absolute or normalised
Because of this, impulse reference data should only be used when the population, protocol and calculation method match closely.
The most relevant peer-reviewed research supports impulse as a task-specific force-time variable, rather than a universal normative score.
In isometric testing, Lum and colleagues reviewed 47 studies and reported that multi-joint isometric force-time variables, including impulse, can show small to very large relationships with dynamic performance. The review also notes that impulse over specific epochs, such as 300 ms, has been related to outcomes such as sprint performance in some studies. This supports the use of impulse as a performance-related metric, but not as a universal “normal value”.
In vertical jumping, Kirby and colleagues reported that relative net vertical impulse was strongly associated with jump height in static and countermovement jumps performed to different squat depths. This supports using relative net vertical impulse as a meaningful reference variable for jump performance, especially when comparing force-time strategies within the same jump protocol.
In basketball monitoring, Philipp and colleagues followed elite NCAA Division-I male basketball players across a season and found that some countermovement jump force-time metrics changed while outcome metrics such as jump height did not. Importantly, some impulse variables did not significantly change across periods, showing that impulse should be interpreted as one part of a broader force-time profile rather than a standalone readiness marker.
In team-sport CMJ research, a 2025 systematic review reported that CMJ performance is influenced by multiple physical and biomechanical characteristics and noted that jump performance depends on generating high impulse relative to body weight. The same review also highlights heterogeneity across CMJ-related measures, which supports cautious interpretation rather than universal impulse thresholds.
For most health and fitness professionals, the best way to interpret impulse is:
Compare the client to their own baseline
Compare left and right sides when relevant
Compare the same test under the same protocol
Use body-mass-normalised impulse when the task involves moving body weight
Use published reference data only when the test, device, population and calculation method match
Interpret impulse with peak force, RFD, time to peak, movement quality, symptoms and performance outcome
Published reference values may be useful when they match:
Same population, such as elite male basketball athletes or rugby league players
Same test, such as countermovement jump or isometric mid-thigh pull
Same device type, such as force plate or load cell
Same calculation method, such as relative net vertical impulse
Same phase, such as propulsive impulse or braking impulse
Same units, such as N·s/kg
If those details do not match, published values should be treated as broad context, not a strict benchmark.
Impulse is often more meaningful when expressed relative to body mass or body weight, especially for bodyweight tasks.
This may be reported as:
N·s/kg
BW·s
Relative net impulse
Body-mass-normalised impulse
This means the result is adjusted for the client’s size.
“Absolute impulse tells us total force-time output. Relative impulse tells us how much force-time output you produced compared with your body size.”
A heavier client may produce a larger absolute impulse simply because they have more mass. However, if the task requires moving their own body, relative impulse may be more informative.
For example:
A 100 kg client and a 70 kg client may have similar absolute impulse.
The 70 kg client may have higher impulse relative to body mass.
That may help explain why the lighter client jumps higher or moves more efficiently in a bodyweight task.
Vertical jump research supports the importance of relative net vertical impulse because jump height is strongly influenced by the impulse generated relative to body mass.
Relative impulse should not be compared across different tests.
For example:
CMJ propulsive impulse is not the same as isometric knee extension impulse.
Braking impulse is not the same as propulsive impulse.
N·s/kg values are not automatically comparable with BW·s values unless the calculation method is known.
Impulse helps clients understand that performance is not just about the highest force number.
You might say:
“Peak force tells us your highest force. Impulse tells us how much force you applied across the movement.”
If impulse increases under the same protocol, this may suggest improved force-time output.
For example:
Higher propulsive impulse may support better jump performance.
Higher early impulse may suggest better rapid force contribution.
Higher total impulse may suggest better force sustainment.
Impulse can reveal side-to-side differences that peak force may miss.
For example, both limbs may reach a similar peak force, but one side may apply less total force over the movement phase.
Impulse can help explain how a client achieved the result.
Two clients may jump the same height but use different force-time strategies. One may produce force quickly. Another may use a deeper, longer movement to accumulate impulse.
Impulse may drop across repeated efforts if the client cannot maintain force-time output.
This can support fatigue monitoring when interpreted with RPE, symptoms, peak force and performance outcome.
Impulse can help guide progression from slow controlled tasks to faster or more dynamic tasks.
For example:
Low total impulse may suggest more work is needed on force capacity.
Low early impulse may suggest the client struggles to apply force quickly.
Improved impulse with stable symptoms may support gradual progression, depending on the broader assessment.
For general fitness clients, impulse is most useful for tracking progress over time. It can show whether the client is applying more force over a task or test window.
Use impulse for:
Baseline tracking
Strength program monitoring
Push-pull assessment
Jump progression
Lower-limb force testing
Avoid comparing general fitness clients to elite sport reference data unless the protocol and population are relevant.
For athletes, impulse can be useful because sport tasks often depend on applying force within limited time windows.
Relevant tasks include:
Jumping
Sprinting
Landing
Cutting
Decelerating
Accelerating
Contact or collision tasks
Athletes may need both high impulse and appropriate timing. A high impulse produced slowly may be less useful in tasks requiring short ground contact times.
For older adults, impulse may help show how force is applied across functional tasks such as sit-to-stand, stepping or balance-related movements.
However, interpretation should consider:
Balance
Confidence
Movement speed
Symptoms
Strength
Functional performance
Familiarity with the test
Impulse may be useful, but simple functional measures may sometimes be more meaningful for client education.
For clients with pain, impulse can show how much force they are willing or able to apply across the test.
A low impulse may reflect:
Pain
Guarding
Reduced confidence
Apprehension
Reduced force capacity
Fatigue
Strategy change
Record symptoms and pain score so the number has context.
Impulse can help track whether force-time output is improving across a specific task.
For example:
Peak force may return before impulse normalises.
Propulsive impulse may remain lower on one side.
Braking impulse may show a strategy difference during jumping or landing tasks.
This should support monitoring, not standalone clearance.
For youth clients, impulse changes may reflect growth, maturation, coordination, body mass changes, training age or familiarisation.
Use baseline and repeat testing rather than adult reference values unless youth-specific data are available for the exact protocol.
For higher body mass clients, absolute impulse may be high, but body-mass-normalised impulse may provide better context when assessing bodyweight tasks.
Use both absolute and relative values where useful.
Not always. Higher impulse may be useful, but it may also reflect a slower or deeper strategy.
No. Low impulse may reflect reduced force, shorter movement time, pain, fear, fatigue, unfamiliarity or task strategy.
No. Peak force is the highest force. Impulse is force applied over time.
No. You need to know whether it is total, braking, propulsive, net, early or late impulse.
No. Published impulse values are only useful when the test, device, phase, calculation method and population match.
No. Normalisation helps, but age, sex, training history, body composition, technique and task familiarity still matter.
Impulse can be affected by:
Device type
Sampling rate
Filtering
Start and end thresholds
Movement phase definition
Time window selection
Body mass
Warm-up
Instructions
Familiarisation
Pain
Fatigue
Technique
Motivation
Test environment
Footwear or surface in movement tests
Research on force-time testing shows that methodological choices such as thresholds, filtering and calculation methods can affect force-time variables. In one season-long basketball study, force-time metrics were grouped into strategy, driver and outcome variables, highlighting that interpretation depends on how the metric is defined and used.
To improve impulse data quality:
Use the same device each time
Use the same unit each time
Record the impulse type
Record the time window
Record the movement phase
Use the same test setup
Use the same instructions
Standardise warm-up
Allow familiarisation trials
Record multiple trials
Use the same scoring method
Record body mass if using relative impulse
Record pain, symptoms and effort
Interpret impulse with peak force, RFD and time to peak
Avoid comparing different protocols
Record:
Metric: Impulse
Score/result: impulse value
Units: N·s, kg·s, lb·s, N·s/kg, BW·s or device-specific unit
Impulse type: total, net, braking, propulsive, early, late or phase-specific
Time window: for example, 0–100 ms, 0–200 ms, total contraction, braking phase or propulsive phase
Test name: countermovement jump, isometric knee extension, isometric pull, push test or other test
Side: left, right or bilateral
Dominance: dominant or non-dominant side
Position: seated, standing, supine, prone or sport-specific position
Device used: force plate, load cell, dynamometer, Muscle Meter or other device
Trial number: trial 1, trial 2, trial 3
Final score method: best score, average score or selected trial
Body mass: if normalising impulse
Pain score: before, during or after testing
Symptoms: pain, apprehension, fatigue, cramping or none
Effort quality: maximal, submaximal, hesitant or unclear
Related metrics: peak force, RFD, time to peak, fatigue index, jump height or torque
Baseline comparison: previous result
Retest date: planned follow-up
Progress note: contextual factors that may explain the result
Measurz should be used to support measurement, comparison, monitoring, education and progress tracking. Impulse should not be positioned as diagnosing a condition or confirming readiness on its own.
A client increases propulsive impulse during a countermovement jump and jump height also improves. This may suggest improved force-time output during the propulsive phase.
A client increases total impulse by using a much deeper countermovement and taking longer to jump. This may not be positive if their sport requires fast ground contact or rapid movement.
A client shows similar peak force between limbs but lower impulse on one side. This may suggest they can reach a high force but do not apply force as effectively across the measured phase.
A runner has acceptable total impulse but low early impulse. This may suggest they apply force too slowly for tasks with short contact times.
A client improves peak force symmetry, but propulsive impulse remains lower during a unilateral jump. This may suggest peak force alone is not capturing the full force-time difference.
A client has high absolute impulse but lower body-mass-normalised impulse. This may mean their total force-time output is high, but the relative output available to move their body is lower.
Impulse is the total force applied over a selected period of time. It is calculated as the area under the force-time curve.
High impulse usually means greater force-time output across the measured phase or window. It may suggest better force application, but it can also reflect a slower or longer movement strategy.
Low impulse usually means less force-time output across the measured phase or window. It may reflect reduced force, shorter force application time, fatigue, pain, hesitation, poor confidence or altered technique.
No. Peak force is the highest force reached. Impulse is total force applied over time.
No. Impulse is force over time. Power includes force and velocity, or work over time.
Impulse is commonly measured in N·s. Some devices may display kg·s, lb·s, N·s/kg or BW·s.
It means impulse is expressed relative to body mass. This can help compare force-time output between clients of different sizes.
There are no universal impulse norms. Published data are usually test-specific, sport-specific, phase-specific and device-specific. Use published values only when the protocol and population match closely.
Impulse helps explain how the client generates take-off velocity and jump height. Relative net vertical impulse has been shown to be strongly related to jump height in vertical jump research.
No. It should be interpreted with peak force, RFD, time to peak, symptoms, movement quality and the client’s goal.
Impulse measures force applied over time.
High impulse usually means greater force-time output, but context matters.
Low impulse usually means reduced force-time output, but it does not explain why.
Impulse must be interpreted with the phase, time window, units and protocol.
Body-mass-normalised impulse can be useful for bodyweight tasks.
Published impulse reference data are task-specific, not universal.
Measurz should record impulse with units, phase, time window, symptoms and related metrics.
Kirby, T. J., McBride, J. M., Haines, T. L., & Dayne, A. M. (2011). Relative net vertical impulse determines jumping performance. Journal of Applied Biomechanics, 27(3), 207–214. https://doi.org/10.1123/jab.27.3.207
Lum, D., Haff, G. G., & Barbosa, T. M. (2020). The relationship between isometric force-time characteristics and dynamic performance: A systematic review. Sports, 8(5), Article 63. https://doi.org/10.3390/sports8050063
Philipp, N. M., Cabarkapa, D., Nijem, R. M., & Fry, A. C. (2023). Changes in countermovement jump force-time characteristic in elite male basketball players: A season-long analyses. PLOS ONE, 18(9), Article e0286581. https://doi.org/10.1371/journal.pone.0286581
Pocek, S., et al. (2025). Physical and biomechanical relationships with countermovement jump performance in team sports: Implications for athletic development and injury risk. Sports, 13(8), Article 277. https://doi.org/10.3390/sports13080277
