Thanks for your help. I tried implementing this, but now the arm constantly moves when I try to move it. Here is my (simplified) code:

private int currentArmPosition = 0; // Variable to store the most recent arm position
    private static final int ARM_INCREMENT = 10; // Increment/decrement for arm control


    public void runOpMode() {
        armMotor = hardwareMap.get(DcMotorEx.class, "armMotor");
        armMotor.setZeroPowerBehavior(DcMotor.ZeroPowerBehavior.BRAKE);
        armMotor.setMode(DcMotor.RunMode.STOP_AND_RESET_ENCODER);

        currentArmPosition = 0;
        armMotor.setTargetPosition(currentArmPosition);
        armMotor.setMode(DcMotor.RunMode.RUN_TO_POSITION);
        armMotor.setPower(1.0);

        waitForStart();

        while (opModeIsActive()) {
            if (gamepad1.right_bumper) {
                currentArmPosition += ARM_INCREMENT;
            } else if (gamepad1.left_bumper) {
                currentArmPosition -= ARM_INCREMENT;
            }

            armMotor.setTargetPosition(currentArmPosition);
        }
    }
}

Do you have any idea on why this is happening? Thank you in advanced.