Workers’ Compensation · Primary-source case analysis

Strong: A Prior Award for Another Body Region Can Still Overlap

By Aneeta Mishra and Timothy Chan

Published April 30, 2026 · Updated October 18, 2026

Decision: Strong v. City and Cnty. of San Francisco, No. SFO 0479038 (WCAB Oct. 26, 2005) (en banc).

A prior knee or shoulder award does not answer a later back-disability claim simply by naming a different body part. Strong examined whether the old and new disabilities affected the same work abilities. But its 2005 statement that the worker must disprove overlap cannot be used as today’s burden rule: The Court of Appeal later rejected that allocation in Kopping v. WCAB.

Keep two questions separate: Does the prior awarded disability legally continue to exist, and how much does it overlap the current disability? A conclusive presumption on the first question does not automatically decide the second.

The new injury involved a different region

Jack Strong, a stationary engineer, had prior awards involving his left knee and later his shoulder, knee, ankle and wrist. The earlier medical record progressed from a restriction against heavy lifting to a light-work limitation. After a May 2002 back injury, the parties stipulated to 70 percent overall disability based on a semi-sedentary-work limitation. The question was how much of that overall disability overlapped the disability already awarded. Strong, slip opinion, pages 3–5.

The judge awarded 10 percent after deducting a 60-percent rating for the prior light-work limitation from the stipulated 70-percent overall rating. Strong argued that different statutory body regions barred the deduction and, alternatively, that the deduction should use monetary values. These were disputes about the relationship between the ratings, not just the names of the injuries. Strong, slip opinion, pages 4–5, 22–24.

Different regions do not preclude overlap

The Board rejected the idea that a different anatomical region necessarily prevents overlap. What mattered was whether the disability factors affected the same abilities to compete and earn. A lifting restriction from a knee injury and a later restriction associated with a back injury cannot be compared accurately by looking only at the words knee and back. The actual restrictions and rating evidence matter. Strong, slip opinion, pages 7–13.

Senate Bill 899 changed the apportionment statutes in 2004, repealing former section 4750 and adding section 4664. Strong concluded that the functional comparison of overlapping disabilities continued, substantially using earlier overlap principles. It did not hold that all older apportionment law remained unchanged; it expressly recognized the new conclusive presumption tied to a prior award. Strong, slip opinion, pages 10–16, 21–22.

Kopping later rejected the worker’s burden to disprove overlap

Strong required the employer to prove a prior permanent-disability award, then placed the burden on the worker to disprove overlap. That latter step is the part a present reader must not copy. Kopping held that the employer or insurer seeking apportionment must prove both the prior award and the extent of overlap with current disability. The statute conclusively establishes the continued existence of the prior awarded disability; it does not establish overlap by itself. Kopping v. WCAB, No. C051885 (Cal. Ct. App. Sept. 11, 2006), slip opinion, pages 23–26.

Kopping retained the conclusive-presumption point: The worker cannot defeat section 4664(b) by proving medical rehabilitation from a disability covered by a prior permanent-disability award. But showing that prior disability legally persists is different from proving it reduces the present award. The employer still needs the comparison evidence. Kopping, slip opinion, pages 23–25.

For example, a prior award’s percentage alone may not explain the underlying restriction or how it relates to the new disability. Obtain the award, its medical and rating basis, and the current reports. A worker may challenge a claimed overlap without assuming the legal burden shifted merely because an award was produced.

Disposition

In the 2005 Strong decision, the Board affirmed the 10-percent award. It found only partial overlap between the prior light-work limitation and the current semi-sedentary limitation; it did not simply add the percentages of all earlier awards and subtract their total. The opinion expressly left unchallenged the legal correctness of the adjustment producing the 60-percent prior rating and reserved novel questions about comparisons between the 1997 and 2005 schedules. Strong, slip opinion, pages 21–25 & notes 19–20.

Read that historical result together with Kopping’s later correction of the proof burden. This article does not suggest every proposition in Strong was annulled, or that its rating arithmetic can be transferred to a different medical record or rating schedule.

Key takeaways

• Obtain the actual prior award and its medical and rating basis, not just a settlement amount or old percentage.
• Compare functional disability and rating evidence; different anatomy alone does not resolve overlap.
• Apply Kopping’s burden: The employer seeking apportionment must prove the prior award and the extent of overlap.
• Distinguish the conclusive persistence of awarded disability from the separate question whether it overlaps current disability.