A cumulative sentence contains an independent clause serving as a base or “core” element, such as “The football Giants lost today,” and then has phrases appended to the core functioning in either coordinate or subordinate roles. For example,
The football Giants lost yesterday, losing safety Stevie Brown for the season.
Above, “losing safety Stevie Brown for the season” refers to the base clause, shown in bold, “backfilling” it, to use a term in Brooks Landon’s book, Building Great Sentences. It’s also a coordinate phrase and a participial phrase, “losing” a present participle.
To provide more detail, to the coordinate phrase I’ll add a subordinate phrase: “his left ACL torn while returning an interception.” This phrase builds upon “losing safety Stevie Brown for the season,” providing specifics about the injury, thus is subordinate to it.
The cumulative sentence now contains this:
The football Giants lost yesterday, losing safety Stevie Brown for the season, his left ACL torn while returning an interception.