You guess wrong. People who are in drink or drugs can sometimes muster great strength. If someone kicks off, getting them fully restrained with only two officers is an achievement in itself.
Aye, IIRC we (as humans in general) only ever use about 20-25% of our muscle strength day to day - as the body risks serious damage if we use it all, and the muscles themselves are evolved to share the load (some cells basically rest whilst others continue the job).
From memory the muscles in the human body (or at least certain ones) are more than strong enough when used at full potential to cause major harm to the body, hence the normal automatic limiting function the brain imposes (IIRC the arm muscles can provide enough force that they'll tear themselves free from the anchor points as an example).
When someone is drunk/on drugs or under extreme levels of stress (high adrenaline for example) the body can/does ignore the normal safety limits, and that small timid looking fellow, suddenly becomes a lot harder to handle.
It's why certain drugs are considered so dangerous, and why you get reports of people lifting cars etc to get to someone under them.
I've seen it take 4-5 people to stop a single, smallish but very drunk woman in the past.
The video looks very bad for the officers involved, but the video doesn't show everything (for one thing the officers themselves will be blocking the view of some of what was going on).
Rapid, is that the clip of the "OAP" who'd already driven off from the police whilst they were doing a check because he'd committed an offence?
The OAP who ignored the police who were then following him for something like 15 minutes with their lights and sirens, the police who then when he finally stopped used a home office approved method to distract him/immobilise the car and get the keys before he could drive off again, without causing any physical harm to him?
I thought so.