The phrase "a less vigorous" is correct and usable in written English.
It can be used when comparing the intensity or strength of something, indicating that it is not as vigorous as another option.
Example: "The new exercise routine is a less vigorous alternative to the previous one, making it suitable for beginners."
Alternatives: "a milder option" or "a more subdued".
The ballroom version is based on the Cuban son, itself a less vigorous form of the uninhibited Cuban rumba danced in taverns and similar places.
Or, the economic collapse as "a consequence of greed and irresponsibility on the part of some," a less vigorous version of FDR's "The rulers of the exchange of mankind's goods have failed".
The International Monetary Fund has trimmed its growth forecast for the world economy in 2013 after predicting a less vigorous recovery in the US, Britain and the leading countries of the eurozone.
The applicability of previous results can, thus, be tested in a less vigorous, less studied and potentially, somehow, less efficient environment than the stock markets in US.
The stem cells used, mesenchymal stem cells (MSCs), are thought to elicit a less vigorous immune reaction than blood stem cells, and MSCs can develop into bone, along with other connective tissues.
"In fact, turnout was surely affected by many factors including the ID law but also a less vigorous campaign and polling showing Clinton well ahead throughout the campaign," he wrote in an email.
Adelaide Clemens, as the young suffragette Valentine Wannop, may appear a bit less vigorous and sporty than we know her from the novels, but her open-faced radiance and easy, modern humor make her not just an appealing character but also an antidote to the stodgy folk around her.
In addition, the exercise in the present study was a much less vigorous stimulus for provocation of airways and activating the mast cells than allergen provocation in which approximately 200 300% increase is seen in levels of urinary 11β-PGF2α with an allergen challenge[ 34].
I've been temporarily diverted by the need to shift some self-seeded wild primroses from among a spread of less vigorous Barnhaven primulas of a gorgeous blue.
If Roth wrote in a more cautious, less vigorous and provocative way he would not be Roth.
