The claimant, Floyd Wilson, appeals the decision of the Labor and Industrial Relations Commission (Commission), wMch found that he was not entitled to receive workers’ compensation benefits for an acute myocardial infarction suffered while he was working. The claimant argues that the Commission’s decision was not based on competent and substantial evidence, and was against the weight of the evidence. He further asks tMs court to consider two articles published in The New England Journal of Medicine as newly discovered evidence.
On July 25, 1990, claimant, employed by ANR Freight Systems, went to the Hillyard Chemical Company in St. Joseph, Missouri, to pick up a load of freight, weighing approximately 13,000 pounds. Since Hillyard was a new customer, claimant wanted to fimsh the job quickly in order to make a good first impression. The ambient temperature was 85 degrees, and claimant estimated that it was about 30 degrees hotter inside the truck.
While loading the freight, the claimant began to experience angina-type pain, with associated jaw and chest discomfort. He finished loading the truck and went to his next destination. When Ms symptoms did not improve, he went to Heartland East Hospital in St. Joseph, where he was admitted and treated by Dr. StaMey Crie. As part of his medical history, claimant told the doctor at the Heartland East Hospital that the day before he had experienced jaw discomfort. Two days later, claimant was transferred to North Kansas City Hospital, where he was under the care of Dr. John Miller.
There is no dispute that the claimant suffered an acute myocardial infarction. The issue litigated at trial was whether the claimant’s heart attack was causally connected to Ms work related activities on that day. The ALJ made the followmg finding, which was adopted by the Commission:
I find after careful review of all the evidence and testimony provided that the myocardial infarction which the claimant suffered on July 25, 1990, was not triggered, induced or precipitated by the claimant’s work activities of July 25, 1990, and therefore not compensable under the Missouri Workers’ Compensation Act. I make this finding after careful consideration of all the medical expert testimony regarding causation of heart attacks and also in light of the current status of the Missouri Law on their compensability.
In Ms first three pomts, the claimant argues that the Commission’s decision is not supported by substantial and competent evidence. He complains that the testimony of expert witnesses Bell and Crie amounted to incompetent evidence, and argues that the findings of fact and the award are “based on suspicion and conjecture.”
When reviewmg the decision of the Commission, we examine the evidence in the light most favorable to the findings of the Commission and its decision, accepting all reasonable inferences therefrom and disregarding all unfavorable evidence. Reves v. Kindell’s Mercantile Co., Inc., 793 S.W.2d 917, 919 (Mo.App.1990). The Commission’s decision may be set aside only if there is no substantial evidence to support it or if it is clearly contrary to the overwhelming weight of the evidence. Jones v. Jefferson City Sch. Dist., 801 S.W.2d 486, 488 (Mo.App.1990). We will not substitute our judgment for that of the Commission, even if we would have made a different mitial conclusion. Lawson v. Emerson Elec. Co., 833 S.W.2d 467, 471 (Mo.App.1992). The Commission is the sole *661judge of witness credibility and the weight and value of the evidence. Id. at 470-71.
The issue in dispute in this case was causation. The Missouri Supreme Court, in Wynn v. Navajo Freight Lines, Inc., 654 S.W.2d 87 (Mo. banc 1988), set out the standard by which heart attack cases are deemed to be compensable in Missouri:
[T]he right to compensation should exist if the actual triggering causes are found, on the basis of substantial evidence, to meet the “job related” or “work related” test of Wolfgeher.
Id. at 89-90 (citing Wolfgeher v. Wagner Cartage Serv., Inc., 646 S.W.2d 781 (Mo. banc 1983)). Expert medical testimony was provided by three board certified cardiologists. All three physicians agreed that the claimant’s medical history contained several factors which placed him in a high risk category for a heart attack. These include: (1) hypertension; (2) high cholesterol; (3) smoking a pack a day for thirty years; and (4) a family history of heart disease, including a father who died of a heart attack at age 49. The evidence is undisputed that these factors contributed to his heart attack.
The evidence was conflicting, however, with regard to whether heavy physical exertion triggered or precipitated the claimant’s myocardial infarction. Dr. John Miller, the claimant’s treating physician in North Kansas City, testified that it was his opinion that the claimant’s strenuous work activities on July 25, 1990, triggered his heart attack. The claimant also questioned expert witnesses, Drs. Bell and Crie, about several articles from medical treatises which stated that heavy physical exertion may induce myocardial infarctions.
Dr. Hubert Bell testified for the employer that the work performed by claimant was not a precipitating factor. Acknowledging that heavy physical exertion may, on occasion, cause heart attacks, he testified that he did not believe this to be the case with claimant. Dr. Bell stated that the angina-like jaw pain experienced by the claimant the day before his myocardial infarction made it more likely that the claimant’s heart attack was caused by a blood clot which had formed over time.
Dr. Stanley Crie, who was the claimant’s treating physician during the critical first two days at Heartland East Hospital, testified that although some experts in the field do believe that, on occasion, strenuous physical activities may cause myocardial infarc-tions, most people who have myocardial in-farctions have them without physical exertion. Dr. Crie stated that he could not say, to a reasonable degree of medical certainty, whether or not a cause and effect relationship existed between the claimant’s physical exertion and his heart attack. However, citing the jaw pain, indicative of angina, experienced by the claimant the day before his heart attack, it was his opinion that the work conditions did not cause the attack.
Both Drs. Bell and Críe testified on cross examination concerning three articles in medical treatises which linked heavy physical exertion and myocardial infarctions. Regarding Braunwald’s textbook, Heart Disease, the doctors agreed with the text which stated that 13% of heart attack victims were engaged in heavy physical exertion at the onset of the infarction. The article continued to say that there is suggestive evidence that heavy exercise may play a precipitating role in some patients. Another textbook, The Heart, used during the doctors’ cross-examination, states that a single episode of physical stress in individuals prone to heart attacks may trigger infarctions. It further stated that the shorter the time interval between the exercise and the myocardial infarction, the more likely there is a causal relationship. Finally, Dr. Crie testified from an article in The American Journal of Cardiology that the most commonly reported possible triggers of myocardial infarction were emotional upset and physical activity, and that physical activity may predispose to plaque rupture and coronary occlusion, causing myocardial infarction. Dr. Crie testified that he interpreted the articles as saying that there may be occasions when unusual physical exertion could precipitate or cause a myocardial infarction, but in general that is not the case.
The claimant dedicates much of his brief to attacking the testimony of Drs. Bell and Crie, in an attempt to discredit their medical opinions. The thrust of his argu*662ment is that the testimony of Drs. Bell and Crie did not constitute substantial evidence on which the Commission could base its finding that the claimant’s heart attack was not work related. It is possible to argue discrepancies in their testimony but we have carefully reviewed all of the testimony and specifically the medical testimony and conclude that the opinions of Drs. Bell and Crie were based on substantial evidence.
It is the claimant’s burden to prove all material elements of his claim. Haynes v. Emerson Elec. Co., 799 S.W.2d 989, 947 (Mo.App.1990). In order to prevail, the claimant was required to present evidence to convince the Commission that his heart attack was “job related” or “work related” within the meaning of Wynn. Id. The employer, ANR Freight, was not required to present substantial evidence that claimant’s heart attack was not job-induced. Id. The Commission chose not to believe Dr. Miller’s testimony in weighing all of the evidence and evaluating the credibility of the witnesses.
The claimant presented, as evidence of causation, the testimony of Dr. Miller that his heart attack was work-induced, and several articles from medical treatises which stated that heavy physical exertion may precipitate myocardial infarctions. The Commission, however, was not required to believe that this evidence established causation, even if no contradictory or impeaching evidence is introduced. Page v. Green, 686 S.W.2d 528, 530 (Mo.App.1985). The court of appeals must disregard any evidence which might support a finding different from that of the Commission, even though a finding to-the contrary would have been supported by the evidence. Stockman v. J.C. Indus., Inc., 854 S.W.2d 24, 26 (Mo.App.1993).
The facts of this case presented a difficult medical question on which qualified experts held conflicting opinions. “[W]here the right to compensation depends upon the acceptance of one of two conflicting medical theories, the issue is one of fact for determination by the Commission.” Haynes, 799 S.W.2d at 948 (citing Low v. ACF Indus., 772 S.W.2d 904, 906 (Mo.App.1989)). The Commission did not believe that the claimant proved causation, and that was for the Commission to decide.
In his final point, the claimant asks this court “for its equitable interference with the Commission’s finding ... on account of newly discovered evidence published in the December 2, 1993 issue of The New England Journal of Medicine.” The evidence consists of two articles entitled, “Triggering of Acute Myocardial Infarction by Heavy Physical Exertion,” and “Physical Exertion as a Trigger of Acute Myocardial Infarction.” These articles were not presented to the ALJ or to the Commission and are first proffered in this court as “newly discovered evidence.”
The general rule is that presentment of evidence extraneous to the trial court record should not be considered on appeal. Crestwood Commons Redevelopment Corp. v. 66 Drive-In, Inc., 812 S.W.2d 903, 909 (Mo.App.1991). Appellate court review is structured by the statutes. In a workers’ compensation review, § 287.495.1, RSMo 1986, states in part as follows:
Upon appeal no additional evidence shall be heard and, in the absence of fraud, the findings of fact made by the commission within its powers shall be conclusive and binding. The court, on appeal, shall review only questions of law and may modify, reverse, remand for rehearing, or set aside the award upon any of the following grounds and no other:
(1) That the commission acted without or in excess of its powers;
(2) That the award was procured by fraud;
(3) That the facts found by the commission do not support the award;
(4) That there was not sufficient competent evidence in the record to warrant the making of the award.
(Emphasis added). Although the act should be liberally construed in favor of the employee, to secure its benefits to the greatest number, procedures outlined for appeal by this section are mandatory. Knuckles v. Apex Indus., Inc., 762 S.W.2d 542, 543 (Mo.App.1988). Absent ambiguities in the statute, strict compliance with the requirements of the workers’ compensation law relating to review and appeal are jurisdictional. *663Abrams v. Ohio Pac. Express, 819 S.W.2d 338, 342 (Mo. banc 1991). Abrams involved the construction of an ambiguity in the statute concerning the time of posting of an application for review which had been imprinted by a postage meter, and the meaning of the word “endorsed.” In our case, the words of § 287.495 are plain and clear and leave no room for construction. They admit to but one meaning. See State ex rel. Missouri State Bd. of Registration for the Healing Arts v. Southworth, 704 S.W.2d 219, 224 (Mo. banc 1986). While Abrams addresses the timing provisions of § 287.480, RSMo. 1986, dealing with the procedure to be followed when appealing a decision of an ALJ to the Commission, the same principle applies when a party appeals the decision of the Commission to the circuit court, § 287.490, and to the appellate court, § 287.495. When no ambiguity exists, there is no need to resort to rules of construction and the statute requires strict compliance. Abrams, 819 S.W.2d at 340.
The scope of appellate review of a workers’ compensation case is limited to the four grounds specified in the statute. Katzenberger v. Gill, 690 S.W.2d 473, 475 (Mo.App.1985). Our jurisdiction is derived from § 287.495, which does not provide for a disposition and remand on the basis of newly discovered evidence which is presented in the first instance to this court. It clearly defines our review to the four grounds set forth, and “no other” grounds. There exists no authority for an appellate court to consider newly discovered evidence first presented on appeal.
Nevertheless, our case law has dealt with the subject. There are only three eases in Missouri which our research has discovered that have allowed “newly discovered evidence” to be considered when the matter was first presented to the appellate court. All three cases were criminal matters and in two of the cases, the newly discovered evidence completely exonerated the defendant who had been convicted. In State v. Mooney, 670 S.W.2d 510 (Mo.App.1984), the only witness to support the defendant’s conviction of molestation was a “troubled youth” who, after the time for the filing of a motion for new trial, was taped admitting that he lied under oath at the defendant’s trial and made up his testimony. The court in Mooney relied upon State v. Harris, 428 S.W.2d 497 (Mo.1968), which held that “where it appears from competent and satisfying evidence that a witness for the prosecution has deliberately perjured himself and that without his testimony [the] accused would not have been convicted, a new trial will be granted.” Id. at 501. In State v. Williams, 673 S.W.2d 847 (Mo.App.1984), both the Prosecuting Attorney of St. Louis County and the Missouri Attorney General agreed that jurisdiction should be returned to the trial court for the purpose of conducting a hearing on a motion for new trial based upon newly discovered evidence. id. at 848. The third case, State v. Post, 804 S.W.2d 862 (Mo.App.1991), involved newly discovered evidence of juror misconduct. The defendant was convicted of murder in the first degree and sentenced to life imprisonment without eligibility for parole. While the appeal was pending, the defendant filed a motion to remand for a new trial because of the activities of at least five deputy sheriffs not assigned to the case who visited with the sequestered jury in their hotel rooms. The deputy sheriffs engaged in card-playing, beer-drinking, and casual conversation with and in front of the jurors about the case, and one deputy had sexual relations with a juror. The court found the law enforcement officers’ conduct outrageous and held that the jury was denied the opportunity and ability to act as a sequestered jury so that they were distracted from “due and fair consideration of the facts.” Id. at 863.
Those extraordinary circumstances do not exist here. There is no basis for our review of this claimed error.
Although not necessary to the disposition of this issue, even if the newly discovered evidence had been presented after trial to the ALJ or Commission,1 it would fail *664because the evidence is cumulative and is evidence which is designed to test the witnesses’ knowledge and credibility. In this more traditional situation, the eases are replete with admonitions that motions for new trial on grounds of newly discovered evidence are not favorites of the law. Williams v. McCoy, 854 S.W.2d 545, 554 (Mo.App.1993). Courts should grant such motions only in exceptional circumstances. Id.
A party seeking a new trial on the ground of newly discovered evidence presented in the first incidence to the ALJ or the Commission must show the following: (1) the evidence came to the movant’s knowledge since the trial; (2) due diligence would not have uncovered the evidence sooner; (3) the new evidence is so material it would probably have produced a different result had it been presented at trial; (4) the new evidence is not merely cumulative of evidence already presented; and (5) the evidence is not offered to impeach the character or credibility of a witness. Id. (citing Young v. St. Louis Public Serv. Co., 326 S.W.2d 107, 111 (Mo.1959)).
The journal articles advanced by the claimant meet the first two requirements. The articles were not published in the New England Journal of Medicine until December 2, 1993, approximately three months following the Commission’s decision. There is substantial doubt as to whether the claimant has satisfied the third requirement. However, we address only the fourth and fifth elements.
The fourth element requires that the new evidence must not be cumulative of evidence presented at trial. The articles here are cumulative to evidence considered by the Commission. Dr. Miller testified that about 50% of myocardial infarctions were causally related to physical exertion, while 50% were not. Additionally, Dr. Crie testified from several articles printed in authoritative medical studies which linked heart attacks to physical exertion that most experts in the field believed that heavy exertion could, on occasion, cause heart attacks. In particular, he testified that one study, published in The American Journal of Cardiology, showed that the most commonly reported triggers of myocardial infarction patients were emotional upset and physical activity.2 In the final analysis, the studies all come to the same conclusion—that there appears to be a causative link between physical exertion and heart attacks. The new evidence may be more authoritative, but that confirms our holding that it is cumulative.
The final requirement states that the object of the evidence must not be to impeach the character or credibility of a witness. The articles in The New England Journal of Medicine are hearsay. Kelly v. St. Luke’s Hospital, 826 S.W.2d 391, 396 (Mo.App.1992). Medical journal articles are not admissible as independent, substantive evidence. Hemminghaus v. Ferguson, 358 Mo. 476, 215 S.W.2d 481, 489 (1948). See also Cooper v. Atchison, T. & S.F. RR. Co., 347 Mo. 555, 148 S.W.2d 773, 780 (1941), cert. denied, 313 U.S. 591, 61 S.Ct. 1116, 85 L.Ed. 1546 (1941) (medical textbooks). This is because if the articles were asserted as substantive evidence, they would be hearsay offered to prove the truth of the matter asserted. Ball v. Burlington Northern RR. Co., 672 S.W.2d 358, 362 (Mo.App.1984).
Medical journal articles may be used on direct or cross-examination to test the knowledge of the expert witness and the reliability of his opinion. See Stallings v. Washington Univ., 794 S.W.2d 264, 270-71 (Mo.App.1990) (direct examination); Ball, 672 S.W.2d at 363 (cross-examination). This is usually accomplished by reading from the publication and asking the expert if he agrees with the statement, as was done in this case with the three medical articles which were used at trial. Langley v. Mi*665chael, 710 S.W.2d 373, 377 (Mo.App.1986). However, this use of an article does not change the character of the evidence even if, as in Stallings, it is used on direct examination of a medical witness as data upon which the witness bases an opinion. § 490.065.3 RSMo.Supp.1993. The medical articles are still hearsay and remain as evidence that tests the credibility or knowledge of the witness; i.e., the facts or data upon which the witness bases the opinion. Stallings, 794 S.W.2d at 271; Ball, 672 S.W.2d at 362. The medical articles do not become transformed into substantive evidence.
In his brief, claimant states that both Drs. Bell and Crie testified that they were unaware of any medical text that conclusively established a link between heavy exercise and myocardial infarctions. Since the articles are inadmissible as independent evidence, the only use to which they could be put is to test the knowledge of the experts and to challenge the factual basis for their opinions. The claimant has not satisfied the fifth requirement of the test stated in Williams. Therefore, even if claimant had presented the journal articles to the Commission as newly discovered evidence, he failed to meet the requirements of Missouri case law. Point denied.
The decision of the Commission denying compensation is affirmed.
BRECKENRIDGE, J., concurs in separate opinion.
ELLIS, J., dissents in separate opinion.
. The Commission has authority to hear newly discovered evidence and its decision whether or not to hear additional evidence under § 287.480, RSMo 1986, is discretionary. Had the claimant presented the newly discovered evidence to the Commission, its decision would be subject only *664to review for an abuse of discretion. See Schneider v. Ashburn/Schneider Painting, 849 S.W.2d 271, 273 (Mo.App.1993).
. The dissent criticizes this study because it lacked sufficient prospective control data on the relationship between the triggers and the onset of the heart attack. This simply goes to the weight the evidence should be given. The very argument the dissent makes, that the newly discovered evidence should be considered because it is more probative, proves the cumulative nature of the new articles.