Opinion by
Judge Doyle,Pedro Serrano (Claimant) appeals from a decision of the Workmen's Compensation Appeal Board (Board) which reversed a referees reinstatement of Claimants partial disability benefits.
Claimant suffered a work-related low back injury on December 13, 1978 in the course of his employment as a construction worker with C. Erickson & Sons (Employer). He received benefits for total disability from the date of the injury until June 29, 1979, when Employer filed a termination petition. On August 6, 1980, a referee issued an order terminating Claimants benefits as of June 18, 1979. This order was affirmed by the Board on February 19, 1981.
On July 10, 1981, Claimant filed a reinstatement petition, alleging that benefits should be reinstated as of June 18, 1979, the same date they had been terminat*622ed. Pursuant to this petition, a referee determined that since the termination date, Claimants condition had deteriorated to the extent that as of June 26, 1981, he was re-eligible for partial disability benefits. In support of his decision to award partial rather than total benefits, the referee indicated that Claimant was capable of performing light duty work, and that such work was available to him.
Claimant and Employer both appealed from this decision, Claimant contending that the finding regarding availability of light duty work was not supported by the record, and Employer contending that the finding that Claimants condition had worsened was not supported by the record. The Board sustained Employers appeal and dismissed Claimants. Claimant now appeals to this Court alleging that the referee made a credibility determination in favor of Claimants medical experts, and the Board exceeded its scope of review in overturning this determination. Claimant has also preserved his argument with respect to the availability of light-duty work.
In a workmens compensation case, the referee, and not the Board, is the ultimate fact finder. Lesneski v. Workmen's Compensation Appeal Board (Pittsburgh Press Co.), 94 Commonwealth Ct. 18, 503 A.2d 73 (1985). The Board is limited, as is this Court, to determining whether substantial, competent evidence supports the referees findings of fact or whether an error of law was committed. Id. In the present case, the Board determined that a necessary finding by the referee, viz., that Claimant’s condition had changed for the worse since his benefits were terminated, was not supported by substantial competent evidence in the record. We agree.
In a reinstatement petition the claimant bears the burden of establishing that a disability has increased or recurred after the date of the prior award, and, to meet *623this burden must show that his or her physical condition has actually changed in some manner. Harry Halloran Construction Co. v. Workmen's Compensation Appeal Board, 39 Pa. Commonwealth Ct. 272, 395 A.2d 325 (1978); Memorial Osteopathic Hospital v. Workmen's Compensation Appeal Board (Brandon), 77 Pa. Commonwealth Ct. 518, 466 A.2d 741 (1983).
Employer correctly points out that an increase or recurrence of disability was not even alleged by Claimant in this case. His petition for reinstatement indicated that since the termination date he has been continuously disabled. To back up his petition, he relied on the testimony of Dr. Rabson, who examined Claimant the first time on June 26, 1981, and concluded on the basis of that examination that he currently was unable to do construction work due to a chronic lumbosacral strain. Dr. Rabson had no knowledge of Claimants prior condition or injury other than that gained through notes which were taken by the doctors secretary on the basis of information gathered from Claimant himself. When asked whether or not he would have found Claimant disabled in June of 1979, Dr. Rabson was unable to venture an opinion either way. The doctor did express an opinion, in the form of a conclusion, that Claimants condition had worsened since June of 1979. When asked the basis of such opinion, however, Dr. Rabson stated that since two doctors had testified in June of 1979 that Claimant was able to return to work, and since in his own opinion, Claimant was currently unable to work, then the conclusion must be that Claimant had worsened. Dr. Rabsons opinion, however, could just as well represent a medical opinion that differed from the medical evidence relied upon by the compensation authorities that formed the basis of their determination to terminate as of June of 1979. In other words, Dr. Rabsons medical opinion could simply represent an ongoing *624dispute over whether the disability of the Claimant had ceased or terminated in 1979. The Claimant is really advancing the argument that his disability never ceased, but continued.
Substantial evidence has been defined as such relevant evidence as a reasonable mind might accept as adequate to support a conclusion. Jerry Green & Sons v. Workmen's Compensation Appeal Board, 63 Pa. Commonwealth Ct. 263, 437 A.2d 1279 (1981). We agree with the Board that Dr. Rabsons testimony did not constitute substantial evidence of a change in Claimants condition. As Employer points out, the usual situation in a termination case is that the employer will present expert testimony that the claimants disability has ceased, and the claimant will present contradictory expert testimony that it has not. If a claimant is permitted to base evidence of a change or recurrence for reinstatement purposes on the mere fact that a credibility determination with respect to his allegedly continuing disability was rendered against him on a prior occasion, the requirement that Claimant prove such a change would be rendered absolutely meaningless. Because of our resolution of this issue we need not consider whether the record supports the referees finding of work availability.
We will affirm the Board.
Order
Now, October 31, 1986, the order of the Workmens Compensation Appeal Board, No. A-86000, dated September 27, 1984, is hereby affirmed.