A420 performance testing system
Evaluate and prescribe with state-of-the-art performance testing
Contact a representativeState-of-the-art performance testing system for training, rehab, and research.
Capture force, velocity, power, acceleration, and other KPIs for analysis.
A420 has demonstrated, scientifically to deliver valid, reliable, and accurate measurements. Learn more.
Access your data via desktop computer.
SOPHISTICATED TESTING.
SURPRISINGLY AFFORDABLE.
BETTER PERFORMANCE TESTING
for almost any application

TEST IN UNDER 8 MINUTES
Capture unilateral data from maximum strength to absolute speed.
Measure kinetic, kinematic, and other variables across the strength continuum.
Force
Power
Reaction time
Velocity
Acceleration
Range of motion
Force
Power
Reaction time
Velocity
Acceleration
Range of motion


Clear visual graphs make it easy to spot key trends and relationships.
Access raw data to crunch your own numbers if needed.

Track where max power is achieved during any concentric range of motion.

Identify unilateral imbalances that lead to injury and underperformance.

Evaluate data during the entire range of motion of each repetition.
TEST ALMOST ANY MOVEMENT PATTERN
YOU CAN TRAIN ON KEISER
A420 turns any new Keiser resistance machine into a state-of-the-art testing device
FUNCTIONAL CABLE MACHINES
RESISTANCE MACHINES
RACKS

VALID RESULTS YOU CAN RELY ON
The problem with compound, independent movements.
Measurable changes in performance can come from adaptation and technical execution of the movement.
It's difficult to know how much improvement came from adaptation or improved technical execution.
Changes in execution between reps and between test make results less repeatable and therefore, less reliable.
Keiser A420 resistance machines fix those problems.
A420 resistance machines confine movement to remove technical execution as a factor.
You know that you are measuring improvement that comes from adaptation.
Results are more consistently repeatable, and differences can’t be attributed to technical execution.
VERTICAL JUMPS AND FREE WEIGHT SQUATS VS. A420 LEG PRESS
SOPHISTICATED, YET SIMPLE
A420 is sophisticated enough for scientific research. But it’s simple enough to be used
by anyone.
1
Enter the participant's 1RM
Set up a test by entering the participant's estimated one-repetition maximum for the motion you’d like to test.
2
A420 automatically creates the test
The A420 automatically creates 10 resistance settings based on the participant's 1RM.
3
Participant takes the test
The system prompts the participant to move as fast as possible at each resistance level, with time for rest between reps.
YOU CAN'T SEE THIS BY MEASURING STRENGTH ALONE
The A420 makes it easy to spot performance issues you can’t afford to miss.

Example: An athlete recovering from a left-leg injury.
1
The absolute, isometric strength of the left leg (blue line) and right leg (red line) is nearly identical. If you only measured strength, you’d think this athlete has fully recovered from their injury.
2
But the left leg is measurably slower than the right leg with a maximum velocity that is almost 11% slower.
3
This disparity reveals a deficiency in peak power output in the left leg (blue line) that could affect performance. Further, targeted rehabilitation can bring the athlete up to return-to-perform condition.
FOUR POWERFUL CHARTS REVEAL THE INSIGHTS YOU NEED
Create baseline profiles. Track and assess progress. Quickly see underlying imbalances and deficiencies at a glance.

VARIABLE TEST CHART
Illustrates the participant’s force-velocity power profile to quickly see unilateral relationships between strength, speed, and power.

FORCE-VELOCITY COMPARISON GRAPH
Compare multiple test to track progress over time. Or compare tests between participants.

GRAPH CHART
Evaluate data during the entire range of motion of each repetition to understand kinetic and kinematic relationships.

BY REP CHART
See left-right unilateral comparisons to find imbalances in power, work, range of motion, and reaction time.

CRUNCH YOUR OWN NUMBERS WITH ACCESS TO RAW DATA
Get detailed numeric data for your own analysis. It’s perfect for scientific research studies or anytime you need direct access to data.
KEISER'S UNIQUE APPROACH TO RESISTANCE MAKES IT POSSIBLE
1
Small, precise increments of resistance
Keiser machines can be adjusted in increments as small as one-tenth of a pound or kilogram.
A420 can calculate precise resistance settings for each participant
2
Digitally controlled resistance
Keiser's resistance is controlled digitally.
A420 automatically creates custom resistance settings and administers the test from the A420 computer.
3
Low-inertia design
With Keiser's low-inertia design, you can train at any speed
A420 can test the high-velocity end of the strength continuum, providing velocity, power, and acceleration insights.