The employer and insurer appeal from the judge’s finding that the employee’s injury arose out of his employment.  We affirm.

The employee was employed by Robert L. Carr Co. [the employer].  On August 12, 2009, while working at the Waseca Wastewater Treatment Plant construction site, the employee injured his left knee.  According to the record, the employee’s symptoms occurred while he was exiting a construction trailer.  Having stepped to the ground with his left foot, he went to step down from the stairs with his right foot, and, turning to the right, he felt a sharp pain in his left knee.  At the time of this incident, the employee was wearing work boots that had extra traction, with grips to prevent sliding, and his left foot was planted on an area of grass and dirt.

The employee filed a claim petition on September 2, 2009, seeking benefits for temporary total disability from August 12, 2009, undetermined permanent partial disability, and medical expenses.  The employer and insurer denied primary liability.

The employee was diagnosed with a medial meniscus tear of the left knee, and treatment eventually included a left knee arthroscopy with partial medical meniscectomy.  He was released to return to work without restrictions on October 5, 2009.

The employee’s claim petition came on for hearing on July 29, 2010.  At that time, the parties stipulated that, if the employee established that he had sustained a compensable injury on August 12, 2009, the claimed benefits would be payable.  In findings and order filed on September 30, 2010, the compensation judge found that the employee’s injury arose out of and in the course of his employment.  The employer and insurer appeal.

On appeal, the Workers’ Compensation Court of Appeals must determine whether “the findings of fact and order [are] clearly erroneous and unsupported by substantial evidence in view of the entire record as submitted.”  Minn. Stat. § 176.421, subd. 1 (2010).  Substantial evidence supports the findings if, in the context of the entire record, “they are supported by evidence that a reasonable mind might accept as adequate.”  Hengemuhle v. Long Prairie Jaycees, 358 N.W.2d 54, 59, 37 W.C.D. 235, 239 (Minn. 1984).  Where evidence conflicts or more than one inference may reasonably be drawn from the evidence, the findings are to be affirmed.  Id. at 60, 37 W.C.D. at 240.  Similarly, findings of fact should not be disturbed, even though the reviewing court might disagree with them, “unless they are clearly erroneous in the sense that they are manifestly contrary to the weight of evidence or not reasonably supported by the evidence as a whole.”  Northern States Power Co. v. Lyon Food Prods., Inc., 304 Minn. 196, 201, 229 N.W.2d 521, 524 (1975).

On appeal, the employer and insurer contend that the compensation judge erred by failing to determine whether a work-related hazard caused the employee’s injury.  They also contend that substantial evidence does not support the judge’s finding as to causation, alleging that the employee “failed to submit a causation report identifying how any alleged increased risk was a substantial contributing cause of his left knee diagnosis and need for surgery.”  We are not persuaded.

With regard to the question of medical causation, the employee relied on reports from treating physicians.  In a report dated March 29, 2010, Dr. Timothy Walker diagnosed the employee with a left knee medial meniscal tear, caused by a work activity or environment, indicating that the employee “twisted knee going down stairs at work on 8/12/09.”  A similar history is contained in other providers’ records.  There is no evidence suggesting that the employee’s left knee condition was caused by any preexisting condition or other injury.  Substantial evidence supports the judge’s implied finding of medical causation.

The employer and insurer’s other argument on appeal requires more analysis.  Pursuant to Minn. Stat. § 176.011, subd. 16, the term personal injury “means injury arising out of and in the course of employment.”  “In the course of” refers to the time, place, and circumstances of the injury, while “arising out of” refers to the causal connection between the injury and the employee’s work activity.  Gibberd v. Control Data Corp., 424 N.W.2d 776, 780, 40 W.C.D. 1040, 1047 (Minn. 1988).  There is apparently no dispute that the employee’s injury occurred in the course of his employment, in that the employee was on the premises where his employment required him to be, during his working hours, and was walking from the construction trailer to his work area.

For an injury to “arise out of “ employment, “the requisite causal connection - - which need not embrace direct and proximate causation as for a tort - - exists if the employment, by reason of its nature, obligations or incidents may reasonably be found to be the source of the injury-producing hazard.”  Nelson v. City of St. Paul, 249 Minn. 53, 55-56, 81 N.W.2d 272, 275-276, 19 W.C.D. 120, 123 (1957).  In Bohlin v. St. Louis County/Nopeming Nursing Home, 61 W.C.D. 69 (W.C.C.A. 2000), this court indicated that the “increased risk” test^[1] is the primary test in this jurisdiction for determining whether an injury arises out of the employment.

In the present case, the compensation judge made no specific finding as to the existence of an increased risk, per se.  She did, however, make unappealed findings as to the circumstances of the injury, including the fact that the employee was wearing work boots that had extra traction to prevent sliding, and that he had planted his left foot on the ground before turning to the right and experiencing immediate knee pain.  In her memorandum, the judge noted that the employee “was wearing work boots, turning to go to his work area, when his knee twisted and the result was a medial meniscus tear.”  The employer and insurer argue that the employee did not “trip or fall,” suggesting that there is no explanation for the injury.  However, the judge’s findings as a whole imply the conclusion that the employee’s left leg did not turn with him to the right because he was wearing boots with extra traction and his left foot was planted on a grass and dirt surface.  As such, a conclusion as to increased risk may be inferred from the judge’s decision.  We would also note that the injury need not be peculiar to the employment, so long as the injury-producing risk or hazard has its origin or source in the employment.  Briemhorst v. Beckman, 227 Minn. 409, 35 N.W.2d 719, 15 W.C.D. 395 (1949).

The “arising out of” and “in the course of” requirements of Minn. Stat. § 176.011, subd. 16, are not independent, but are elements of a single test of work-connection.  United Fire & Casualty Co. v. Maw, 510 N.W.2d 241, 243 (Minn. Ct. App. 1994) (citing A. Larson, Workmen’s Compensation for Occupational Injuries & Death, §29.00 (1993)).  In any given case, a certain minimum level of work connection must be established.  If the “course of” element is weak but the “arising out of” element is strong, the necessary minimum quantum of work-connection will be satisfied, and vice versa.  “When a line is drawn, there are always cases very close to each side of the line.  No absolute rule can be derived, since there are too many factual variables that could affect the result.”  Bohlin, 61 W.C.D. at 81.

Given the record as a whole, it was reasonable for the compensation judge to conclude that the employee’s injury arose out of and in the course of his employment.  We therefore affirm the judge’s decision.