meaning the "otherwise" word in the contest
I don't get meaning of this sentence (because of the "otherwise" word):
"But whatever the reason, running definitely mitigated the otherwise substantial decline in walking economy that seems to occur with age, he said, a result that has implications beyond the physiology lab. "

Could you rephrase this sentence?
Thanks in advance

Question

meaning the "otherwise" word in the contest
I don't get meaning of this sentence (because of the "otherwise" word):
"But whatever the reason, running definitely mitigated the otherwise substantial decline in walking economy that seems to occur with age, he said, a result that has implications beyond the physiology lab. "

Could you rephrase this sentence?
Thanks in advance

Answer

"running definitely mitigated the otherwise" here means that if there wasn't running, there would only be "substantial decline...", so running makes this decline less severe.

A simpler example of "otherwise":

"Today it's raining on an otherwise beautiful week." - means if it wasn't raining today (or you just ignore today) it would be sunny all week.