This is a workers’ compensation case in which the appellant, Forest McMillan, claims that he sustained a shoulder injury at work. The Workers’ Compensation Commission denied benefits. On appeal, appellant argues that he did prove a compensable injury, that his injury was causally related to his employment, and in the alternative, that his injury aggravated a preexisting condition. We affirm.
In determining the sufficiency of the evidence to sustain the findings of the Commission, we review the evidence in the light most favorable to the Commission’s findings and affirm if they are supported by substantial evidence. Weldon v. Pierce Bros. Constr., 54 Ark. App. 344, 925 S.W.2d 179 (1996). Substantial evidence is such relevant evidence as a reasonable mind might accept as adequate to support a conclusion. City of Fort Smith v. Brooks, 40 Ark. App. 120, 842 S.W.2d 463 (1991). The question is not whether the evidence would have supported findings contrary to the ones made by the Commission; there may be substantial evidence to support the Commission’s decision even though we might have reached a different conclusion if we sat as the trier of fact or heard the case de novo. Tyson Foods, Inc. v. Disheroon, 26 Ark. App. 145, 761 S.W.2d 617 (1988). Where, as here, the Commission has denied a claim because of a failure to show entitlement by a preponderance of the evidence, the substantial evidence standard of review requires us to affirm if the Commission’s opinion displays a substantial basis for the denial of relief. Whaley v. Hardee’s, 51 Ark. App. 166, 912 S.W.2d 14 (1995).
In making our review, we recognize that it is the function of the Commission to determine the credibility of the witnesses and the weight to be given their testimony. Id. The Commission is not required to believe the testimony of the claimant or any other witness, but may accept and translate into findings *88of fact only those portions of the testimony it deems worthy of belief. Id.
Appellant’s primary job consisted of operating a machine that made motor shafts. On Friday, January 13, 1995, near the end of his shift, appellant was taking a part out of the machine he was operating and replacing it with another. While following this procedure, appellant’s shoulder popped, and he experienced extreme pain, which he described as feeling “like somebody drove a shaft down through my neck and all the way down that came out my heel in my foot.” Appellant did not complete any additional production work during his shift; he completed some clerical duties and went home.
Appellant testified that he could not use his left arm that weekend. He returned to work the following Monday, using only his right hand and arm to perform his tasks. He did so again on Tuesday; when his supervisor noticed, appellant explained that he had hurt his shoulder the previous Friday. Appellant testified that he continued to work for more than a full week without seeking medical treatment, explaining that he had separated his right shoulder on two prior occasions, and only received medication as treatment.
Appellant contended that his employer required him to take off work because of his physical problems, and would not permit him to return to work without a full medical release. Appellant was examined at the Austin Medical Clinic on January 23, 1995. Appellant previously sought treatment at this clinic on November 2, 1994, for a similar problem with his left shoulder that he developed while chopping wood at home. The doctor’s notes from his January 23, 1995 visit reflect that the appellant’s problems were the same for which the doctor treated appellant on November 2, 1994.
Doctor Austin gave the appellant a release, but his supervisors would not accept it. Appellant testified that his supervisors told him they would not allow him to come back to work until he was “100%.” Appellant then went to see another physician, Dr. Robert Manis, at which time he was given anti-inflammatory medication and prescribed physical therapy. Dr. Manis’ notes reflect *89chronic pain syndrome secondary to old injuries of the appellant’s shoulders, with capsulitis of the shoulders.
Appellant stated that the physical therapy prescribed by Dr. Manis worsened his condition. He never returned to work for appellee. Appellant testified that he was unable to use his left arm for approximately two and one-half months following the alleged injury.
The Commission affirmed and adopted the Administrative Law Judge’s opinion. The Commission found appellant “to be a most credible witness;” it observed that appellant’s testimony concerning his complaints and the reporting of his problems to appel-lee was undisputed. Nonetheless, the Commission found that the medical evidence was in conflict with appellant’s testimony. In support of this observation, the Commission referred to the notes of Dr. Austin and Dr. Manis. Noting that it is appellant’s burden to prove the job relatedness of any injury, the Commission found that appellant was not entitled to benefits because of the inconsistency between his testimony and the medical evidence. It made the following two conclusions, among others:
3. Claimant has failed to prove by a preponderance of the evidence that he sustained an injury arising out of and during the course of his employment which is compensable under our Workers’ Compensation Laws.
4. Claimant has failed to prove by a preponderance of the credible evidence that his physical problems and/or disability is causally related to his employment.
The Commission’s opinion displays a substantial basis for the denial of relief. Appellant alleges that he sustained an injury as the result of a specific incident that is identifiable by time and place of occurrence. Thus, appellant had the burden of proving a compensable injury by a preponderance of the evidence. Ark. Code Ann. § 11-9-102(5)(E)(i) (Repl. 1996). While the Commission found appellant to be a most credible witness, it also found the medical evidence to be conflicting. Specific reference was made to the doctors’ notes, that in turn referenced old injuries as the possible source of appellant’s pain. The inconsistencies between appellant’s testimony and the medical evidence persuaded *90the Commission that appellant failed to prove entitlement to benefits. The Commission concluded that appellant failed to prove by a preponderance of the evidence that he sustained an injury arising out of and during the course of his employment, or that there was a causal relationship between his injury and his employment. Because we believe there is a substantial basis for the Commission’s denial of relief, we affirm.
In affirming the Commission’s decision, we dispose of all three of appellant’s arguments on appeal. First, appellant argues that he suffered a compensable injury. A “compensable injury” is one “arising out of and in the course of employment. ...” Ark. Code Ann. § 11-9-102(5) (A) (i); see Deffenbaugh Indus. v. Angus, 313 Ark. 100, 103, 852 S.W.2d 804, 807 (1993). “Arising out of the employment” refers to the origin or cause of the accident. Deffenbaugh Indus., 313 Ark. at 103, 852 S.W.2d at 807. Thus, in order to prove a compensable injury appellant must prove, among other things, a causal relationship between his employment and the injury. By concluding that the appellant did not prove that there was a causal relationship between the injury and the employment, the Commission precluded a finding of a compensable injury.
Likewise, appellant’s second argument alleges a causal relationship between his employment and his injury. The Commission’s conclusions, and the findings in support of those conclusions, dispose of this argument.
Appellant offers an alternative argument for his third point: that the injury aggravated a preexisting cumulative trauma injury. This argument also requires proof of a compensable injury. It is the rule “that when a pre-existing injury is aggravated by a later compensable injury, compensation is in order.” Wade v. Mr. C. Cavenaugh’s, 298 Ark. 363, 367, 768 S.W.2d 521, 523 (1989)(emphasis supplied). Thus, to prevail on this alternative argument, appellant must prove a compensable injury, which in turn requires proof of a causal relationship between his employment and the injury. Again, as explained above, the Commission’s conclusions foreclose this argument.
Affirmed.
*91Rogers, Griffen, and Crabtree, JJ., agree.
Pittman and Neal, JJ., dissent.