The phrase "a powerful grip" is correct and usable in written English.
It can be used to describe a strong hold or control over something, whether physically or metaphorically.
Example: "The athlete demonstrated a powerful grip on the barbell, showcasing his strength and determination."
Alternatives: "a strong hold" or "a firm grasp."
Even a decade ago, Chile's armed forces still had a powerful grip on the country, overseeing not only its defense, but also its economic and political affairs.
Tradition has a powerful grip on the Eastern Shore.
The Anglo-Saxons retain a powerful grip on English imaginations.
All-too-often it develops a powerful grip on the mind.
What's more, they have a powerful grip on the nation's collective imagination.
The Dismal had a powerful grip on the literary imagination (before movies).
It is a powerful, gripping story with some strong set-pieces.
"The beauty of this is not those oak trees or the goshawk that's probably in there hunting something at the moment, which is an extraordinary bird, and a powerful, gripping presence, a real enigma.
No amount of disastrous failures or fraudulent wrongdoing, it seems, debars companies such as G4S, Atos and Serco from lucrative new contracts in what is already an £80bn business – and one with an increasingly powerful grip on Westminster and Whitehall.
These new, emergent forms of archival capital have an increasingly powerful grip upon culture and its reproduction.
His appearance at the gun lobby's annual gathering also came at a moment when its powerful grip on gun legislation is under renewed scrutiny because of permissive self-defense laws it has promoted, like the one in Florida that may complicate the prosecution of George Zimmerman, who killed an unarmed teenager, Trayvon Martin, six weeks ago.
