No, it's an adjective (word describing a noun)
The nearest 'connected' verb would be 'strain', i.e. endeavour. There is no original verb - it only exists as an adjective or adverb.
Strenuous is an adjective. Strenuous means requiring or using great exertion.
Strenuous exercise makes me tired.
Strenuous exercise is good for your heart.
The workout was quite strenuous.
According to the Merriam-Webster thesaurus the word challenging has 30 synonyms. The more commonly used ones include backbreaking, difficult, killer, strenuous and sever.
Strenuous describes hard and extended physical exertion or exercise.
The strenuous exercise made my muscles ache.
Too much strenuous exercise can result in jury.
He lifted the boulder, but not without heavy exertion.you can not win without exertion . Your highest exertion is required.
Building the house was a strenuous job, but John's love of hard work showed through.
Some of the days are quite long, and the walking feels more strenuous at altitude.