Considering the article example is a marathon (26.2 miles, burns ~2600 calories) and your example is deadlifting (4 sets of 8 deadlifts @ 175 kilograms burns ~1

Considering the article example is a marathon (26.2 miles, burns ~2600 calories) and your example is deadlifting (4 sets of 8 deadlifts @ 175 kilograms burns ~100 calories - equivalent of running .5 miles).. I'd define this test case as 1.9% as 'Strenuous'.