What do the metrics mean?

In this article, we summarize the key metrics recorded in Output, explaining their significance and how they can be used to enhance training and analyze performances.

Balance & Stability Measures

Balance / Stability Score

• Definition: A measurement of total body balance, calculated by the variance in accelerations across the x, y, and z planes.
• Significance: Lower scores indicate better balance/stability, with normative data shown below.

Error Count

• Definition: Represents how many errors (such as losing balance or collapsing during a plank) occurred in a set.
• Significance: Manual entry used to track progress over time.

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Barbell Velocity Measures

Peak Velocity

• Definition: The highest bar speed during the concentric phase of a lift. It is a single point in time and will always be higher than the mean.
• Significance: Tracks explosive power and is useful for exercises like loaded jumps or Olympic lifts.

Mean Velocity

• Definition: The average speed of the bar across the entire concentric phase of a lift. Unlike peak velocity, it measures from the start until the end of the concentric phase of the lift.
• Significance: Useful for prescribing training intensity and monitoring fatigue during strength and speed training.

Below chart shows the difference between Mean and Peak Velocity.

Power

• Definition: The measure of the rate of doing work.
• Formula: Power (W) = Force (N) × Velocity (m/s)

Mean Power

• Definition: The average production of work over the concentric phase of the lift.
• Significance: Tracks sustained effort and gauges improvements in work capacity.

Peak Power

• Definition: The highest production of work during the concentric phase of the lift.
• Significance: Essential for evaluating top-end performance in explosive lifts.

Relative Mean Power

• Definition: Mean Power relative to the athlete's bodyweight
• Formula: Mean Power / Bodyweight
• Significance: Compares athletes or tracks progress in sports where the strength-to-weight ratio is important.

Relative Peak Power

• Definition: Peak Power relative to the athlete's bodyweight
• Formula: Peak Power / Bodyweight
• Significance: Ideal for weight-class sports or tracking performance in athletes.

Force

• Definition: Push or pull on an object with mass that causes it to change velocity.
• Formula: Force (N) = Mass × Acceleration

Mean Force

• Definition: The average force generated during a rep in the concentric phase.
• Significance: Tracks consistent strength output.

Peak Force

• Definition: The highest force generated during a rep.
• Significance: Critical for assessing maximum strength and force-generation capacity.

Relative Mean Force

• Definition: The average force produced, across a rep, relative to the athlete's body weight.
• Formula: Mean Force / Bodyweight
• Significance: Evaluates performance in weight-class or efficiency-based sports.

Relative Peak Force

• Definition: The highest force produced, during a rep, relative to the athlete's body weight.
• Formula: Peak Force / Bodyweight
• Significance: Ideal for sports where the strength-to-weight ratio is important.

Work

• Definition: The amount of physiological work performed in lifting the weight.
• Formula: Work (kJ) = Vertical Displacement (m) × Gravity (9.81 m/s) × Weight (kg)

Peak Acceleration

• Definition: The highest rate of change of velocity from the start to the end of a rep.

Mean Propulsive Velocity (MPV)

• Definition: The average velocity before acceleration drops below gravity, taking into account any active deceleration that will naturally occur with lighter loads (>75% of 1RM).
• Significance: Ensures quality reps with lighter loads and refines speed and power output.

Impulse

• Definition: Force applied over time.
• Significance: Improves strength in slower lifts or optimizes acceleration in faster ones.

Vertical Displacement

• Definition: The total vertical distance the bar travels during a lift.
• Significance: Helps assess range of motion and technique consistency, ensuring optimal mechanics and identifying potential inefficiencies in movement patterns.

Concentric Time

• Definition: Time taken to complete the upward phase of a lift.
• Significance: Monitors the speed and efficiency of the concentric phase, which is critical for assessing explosive strength, technique, and fatigue during strength and power exercises.

Eccentric Mean Velocity

• Definition: The average speed of the object during the eccentric (lowering) phase of a movement.
• Significance: Eccentric mean velocity tracks controlled speed during weight lowering, aiding explosive, hypertrophy, or strength training goals.

Eccentric Peak Velocity

• Definition: The highest speed reached during the eccentric (lowering) phase of a movement.
• Significance: This metric helps track how explosively an athlete transitions into the concentric phase and can be useful for understanding dynamic control during explosive or reactive training.

Eccentric Time

• Definition: The amount of time spent in the eccentric (lowering) phase of a movement.
• Significance: Tracking eccentric time helps ensure the athlete is controlling the lowering phase of a movement. This is important for strength development, injury risk mitigation, and teaching movement control.

Rep Duration

• Definition: The total time taken to complete one repetition, including all phases of the movement. 
• Significance: Rep duration ensures the athlete is working at the intended tempo, considering all phases of the movement. It’s also a valuable indicator of fatigue and progression over time.

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Strength Endurance and Strength Pathway Velocity Measures

Mean Angular Velocity

• Definition: The average velocity through a specific range of motion.

Peak Angular Velocity

• Definition: The highest velocity within a given range of motion.

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Jump, RSI & Contact Measures 

Contact Time

• Definition: The time spent on the ground from initial foot contact to lift-off.

Air Time

• Definition: The time spent in the air from foot lift-off to landing.

Drive Index

• Definition: The ratio between ground contact time and air time.
• Formula: Contact Time / Air Time
• Significance: Measures efficiency of jump mechanics.

RSI (Reactive Strength Index)

• Formula: RSI = Height Jumped (m) / Contact Time (s)
• Significance: A measure of explosive strength in plyometric activities.

Jump Height

• Definition: The highest point reached during a jump.

Max Jump Height

• Definition: The highest point jumped across a set.

Average Jump Height

• Definition: The average height jumped across a set.

Flight Time

• Definition: Total time between leaving and landing on the ground.

Takeoff Velocity

• Definition: The velocity at the moment of takeoff.

Total Work

• Definition: The total work exerted throughout the movement, from the lowest point to the highest point.

Air / Contact Index

• Formula: Air Time / Contact Time
• Significance: Similar to RSI but calculated differently.

Momentum

• Formula: Momentum (kg·m/s) = Mass × Velocity
• Significance: Identifies the optimal load for jump-based training.

Takeoff Momentum

• Definition: Momentum at the moment of takeoff.

Average Momentum

• Definition: The average momentum during a set.

Max Momentum

• Definition: Maximum momentum achieved during a set.

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Angular Measures (Nordics, Mobility, Strength Endurance & Strength Pathway)

Range of Motion (ROM)

• Definition: The total range a part of the body can move around a joint.

Average Range of Motion

• Definition: The average ROM across the set.

Max Range of Motion

• Definition: The maximum ROM during a set.

Duration

• Definition: The total time to complete a rep.