DISSENTING OPINION by
Judge COHN JUBELIRER.I must dissent from the majority’s opinion.
In a workers’ compensation case, the WCJ is the ultimate fact finder and has the sole prerogative of assessing credibility and resolving conflicts in testimony. Bethenergy Mines, Inc. v. Workmen’s Comp. Appeal Bd. (Skirpan), 132 Pa.Cmwlth. 277, 572 A.2d 838, 841 (1990), affirmed, 531 Pa. 287, 612 A.2d 434 (1992). The WCJ may accept or reject, in whole or in part, the testimony of any witness. Id.
It appears to me that the majority has completely re-weighed the evidence that was before the WCJ in this case, then made the findings and reached the result it wished the WCJ had reached on our multiple remands, but did not. In Trimmer I and Trimmer II, the Court reversed the Board, but seemingly allowed the WCJ to find that Claimant was able to work; it remanded the case back to the WCJ for her consideration of Employer’s modification petition and for her determination of Claimant’s earning capacity. Now the majority has not only reversed the Board, but has also dismissed Employer’s suspension/modification petition and determined that Claimant is entitled to total disability benefits as of January 6, 1995, notwithstanding the fact that he is and has been actually performing the job at issue. In essence, the majority has substituted its discretion for that of the WCJ, and made the findings of fact in this case. It is that with which I must disagree.
This Court is required to affirm findings of fact unless those findings are not supported by substantial evidence. Section 704 of Administrative Agency Law, 2 Pa. C.S. § 704. Substantial evidence has been *148defined as relevant evidence that a reasonable mind might accept as adequate to support a conclusion. Bethenergy Mines, 572 A.2d at 840 (quoting Republic Steel Corp. v. Workmen’s Comp. Appeal Bd. (Shinsky), 492 Pa. 1, 5, 421 A.2d 1060, 1062-63 (1980)). Accordingly, we must determine whether there is rational support in the record for a WCJ’s action. See id. Thus, our review here of the WCJ’s findings of fact should be limited to the question of whether they are adequately supported by the evidence as a whole. Id. I believe Employer produced substantial evidence of record to establish Claimant is capable of performing the job of garage supervisor, regardless of his impairment: because he was actually performing the job of a garage supervisor, Claimant had the earning capacity of a garage supervisor.
In a decision dated April 21, 1999, this Court stated that it “must accept the WCJ’s finding that Trimmer has the physical capabilities and impairments ascribed to him in Dr. Boal’s opinion.” Trimmer I, 728 A.2d at 441. The WCJ found that Dr. Boal had the following opinions regarding Claimant’s physical capacities:
(a) Capable of working up to 8 hours per day
(b) Avoid constant standing
(c) Change position as needed
(d) Occasional crawling/squatting
(e) Frequent lifting up to 50 pounds
(f) Occasional lifting up to 100 pounds
(g) Capable of doing any type of physical work he desires
(h) Capable of performing all the tasks that would be done in a general automobile repair shop, including pulling engines, installing engines, changing tires, [and] installing mufflers.
(WCJ Decision 3/22/04, Findings of Fact (FOF) ¶ 24; Dep. Boal, 6-20-95, at 9, 15, 18; Dep. Boal, Ex. 1.)
In Trimmer II, an unreported decision dated September 6, 2002, this Court instructed Employer “[t]o impute an earning capacity [to Claimant] ... of a garage supervisor in the geographical area with the physical limitations ascribed to [him] by Dr. Boal.” Trimmer II, slip. op. at 5. Both Dr. Boal and Employer’s vocational expert, Rodney Benner, testified that Claimant’s impairment does not prevent him from performing the job of garage supervisor. (Dep. Boal, 6-20-95 at 15, 17-19; Dep. Benner, 7-8-03 at 13, 15-16, 19.) Mr. Benner explained that the garage supervisor position is light work, and “well within” Claimant’s restrictions as set forth by Dr. Boal. (Test. 11-1-95, at 23-24; Dep. Benner, 7-8-03, at 16-17.) As found by Mr. Benner, the Dictionary of Occupational Titles provides that a garage supervisor position involves the “supervision and coordination of activities of mechanics engaged in repairing and servicing trucks and automobiles.” (Test. 11-1-95, at 20, 22.) At the hearing in 1995, Mr. Benner testified that:
A supervisor would schedule work for customers, estimate costs, accepts payment for those services rendered, interacts with customers to ensure satisfactory service. And they assign and train, evaluate mechanics performance, diagnoses, and inspects vehicles, orders parts, maintains inventories, maintains records on station operations. And they perform a variety of other administrative tasks like accounting, tax preparation, and that sort of thing.
(Test., 11-1-95, at 22.) In his deposition in 2003, Mr. Benner testified:
Mr. Trimmer can perform the job of garage supervisor with his impairments according to Dr. Boal. If Dr. Boal’s esti*149mates of his physical capabilities is what we are to be adhering to, Mr. Trimmer’s abilities fall well within that to be able to perform the duties of a garage supervisor. ... There is not a lesser variety of garage supervisor.... Frankly, he’s been doing the job. In my mind, he’s demonstrated the ability to perform this position according to his own testimony.
(Dep. Benner, 7-8-08, at 19.)
This case is unusual in utilizing vocational experts because the evidence presented here was not speculative but, rather, irrefutable. Here, the WCJ needed no additional evidence to infer earning capacity for an impaired garage supervisor; Claimant is an impaired garage supervisor, and vocational experts for both Claimant and Employer agreed that $18,780 is a “conservative” and “fair number” for his earnings. (WCJ Decision 3/22/04, FOF ¶ 25(g, h), 26(k).)
There was substantial evidence to support the WCJ’s finding that Claimant’s physical limitations do not affect his ability to perform the job. Because Claimant is self-employed, he does not receive wages from a third party, which is why it was necessary to impute his earning capacity. Garage supervisors in his geographical area have an annual earning capacity of $18,730 and Claimant, regardless of his impairments, has been actually performing the job of garage supervisor. Both the WCJ and the Board have valiantly attempted to comply with this Court’s repeated remands but, nevertheless, continue to reach this determination. Consequently, because the majority does not agree with this outcome, notwithstanding the expert testimony found credible, it is now taking the determination out of the prerogative of the WCJ and the Board. While I agree that continuing to send this case back to the WCJ and the Board is unnecessary and unproductive, I do not agree that we should substitute our understanding of the position of garage supervisor, and Claimant’s ability to perform the work, for that of the experts found credible by the WCJ. Accordingly, I would affirm the decision of the Board.