1. Flawed “science” - for example: using heart rate as a measure of effort. Performing Hand Strength Assessments using a Bell Curve, Coefficient of Variation, and Rapid Exchange Grip. Utilizing isometric testing or static-to-dynamic strength comparisons.
   
   
2. The subjective opinions of evaluators during lifting assessments (i.e. Visual Estimation of Effort or VEE). Is an estimate good enough?

Can they guess correctly?
Maybe - there is a coin flip’s chance. Peer-reviewed research clearly states that trained therapists are able to accurately identify lifting capacity less than 45% of the time when relying on VEE alone. In similar studies, laypersons do almost as well.

Using antiquated FCE methodology a therapist’s expert opinion is easily rendered moot by another expert opinion. Also, numerous websites detail what a claimant can do during these older FCE models to make the report wholly invalid.

What is it?
X-RTS testing is based on the most basic of scientific principles – Test and Re-Test and it employs a significant degree of distraction making it nearly impossible for a claimant to manipulate the outcome for unwarranted personal gain. It leads to a true reflection of specific limitation which expedites a return-to-work and/or fair settlement for all parties.

X-RTS focuses on two critical aspects of an FCE when it comes to ssessing a claimant’s validity of effort; both are supported by multilayered statistical analysis that is based on nearly two-decades of peer-reviewed research. They’re objective and legally defensible: X-RTS Hand Strength Assessment (H.S.A.) and Lever Arm Lifting Assessment.

Hand Strength Assessment
Current methods (Bell Curve, Coefficient of Variation, and Rapid Exchange Grip) have been found to be only 70% accurate in assessing validity of effort. There have been more than 25 peer-reviewed articles published in the last 20 years that have definitively stated the standard ways of assessing validity of effort during hand strength assessments do not work.

According to published research, the X-RTS H.S.A. is 99.5% accurate in assessing a claimant’s validity of effort during hand strength assessment. Claimants intending to feign weakness cannot do so successfully because the X-RTS approach interrupts the biofeedback loop.

Results of valid testing give a true indication of the client’s ability while invalid effort is reported in a black and white, objective manner. On the reverse is an excerpt from an invalid Hand Strength Assessment report:

Lever Arm Lifting Assessment
Claimants are first asked to perform a “baseline lift” where maximums are found for a series of bilateral and unilateral lifts from varying heights. These maximums are determined either by the client stating they are not capable of lifting more or the therapist’s determination that further increases in weight will not be safe. Later during the FCE, claimants are re-tested on the X-RTS Lever Arm using the same biomechanics employed during the baseline lift.

What makes the Lever Arm so effective is that visual estimations by the claimant of actual workloads applied to the lever arm have an average error of 80%. Unmarked weights can be placed at any of 35 points along the length of the device. Actual workloads are determined not only by the amount of weight added to the device, but also by the position into which the workload is secured.

Persons who fail the validity criteria typically have variation of 30-50% when comparing repeated measures. Persons who have no apparent motivational issues will have 5-15% average variation between repeated measures.

Genuine Effort Since the biomechanical positioning is identical during the “Baseline” dynamic lifts and the Lever Arm lifts, a high degree of reproducibility between repeated measures should be present when a maximum safe voluntary effort is given throughout the lifting evaluation. The client’s average variability between repeated measures, as shown in the table above, was 4.80%. This is considered an extremely consistent presentation consistent with maximum effort. In addition, the client passed the following validity criteria: • Average variability between repeated measures is < 20% • At least half of all comparative lifts have a variability <25% • No single set of comparative lifts have a variability >30%

Invalid Effort The average variability between repeated measures was 73.43%. The client FAILED the validity criteria for this part of the test, based on the following: • Average variability between repeated measures on all the lifts was >25% • At least one set of comparative lifts has a variability >40% • At least half of all comparative lifts have variability >25% • Two or more sets of comparative lifts have variability >30%