As an orthopedic physiotherapist, please feel free to squat past 90 degrees. There is no evidence that squatting deeper is associated with injury risk. A 90 degree limit is completely arbitrary.

Any movements you do in everyday life should be replicated at heavier loads in the controlled, focused environment of a gym.

Squat depth is a whole religious debate, and strong emotions are quick to emerge. Pick something close to 90, call it good. Just be consistent. I like thighs parallel, hips at about knee level, which is usually a bit beyond 90, since the shins rotate forward a bit for balance. But I'm not part of the ass-to-grass (ATG) cult, though I do ATG in CrossFit since CrossFit is in the ATG cult, and I don't want to fend off the inevitable comments.

If it's a hex bar deadlift with the elevated grip, most people are considerably less than 90, depending on body geometry.

Recently listened to Peter Attia’s interview with Ryan Hall about this. Definitely suggested not going to standard depth.

Also on Joe Skipper’s YouTube said the same thing.

They both acted as if it was actually counterproductive to do so.

Not replying to you in particular. My understanding is that around 90° is where the knee is handling more stress. And the point where you stop and return is the point where you spend more time. You should try to avoid spending the mood time where the stress to the knees is higher.

If this is correct you would either not want to reach 90°, or go past it. How much above or beyond I guess is debatable.

Wow, I haven't heard someone say don't go to 90degrees in years! I thought this stupid mentality had died like 2 decades ago!!!
It's amazing how dumb things don't die.

I just heard a parent at the pool telling their kid they couldn't go in until 30 minutes after he ate.

I thought so myself, until Ryan Hall mentioned this. Left me a bit confused. Also talking about Meb Keflezighi and his supposed concentric while eliminating eccentric motion.

Why not do the exercises most specific to your goal? For cycling there's not much reason to go past 90deg. For running there's even less reason. Likewise it's probably better to keep your stance a bit narrower than wider and feet more forward pointing.

If you're training for Olympic lifts you better be squatting past 90 since that's how both of your events start.

Specificity only works to a point. Goal of resistance training is to build strength and hypertrophy. An exercise that optimises these things is likely going to produce a better performance outcome regardless of it looking similar to cycling. Low cadence work is a example of this, it's much more specific to cycling, but arguably less effective. A squat is probably better than single leg work, even though that better reflects cycling.

A deeper squat gets more glute activation. Lots of benefits to that, including potentially balanced out more over developed rectus femorus from lots of cycling.

Deeper squat is also good for maintaining flexibility.

Deeper squat means less weight on the bar, which may decrease risk of injury.

I don't see a good reason to not squat deep. Ime it's mostly down to ego (the less deep you squat the more weight you can put on the bar) or lack of flexibility (in which case you should focus on improving that the have a full range of motion).

Completely correct that you could get too specific, especially for off-season stuff like lifting.

Regardless of depth I would still shy away from the traditional wide stance, feet splayed type squat. It has a ton of activation on the adductor magnus (had to look up that name) which is minimally important to running and cycling.

This might be falling into bro-science territory, but I'd argue a 500lb half squat is better for cycling than a 300lb ATG squat. Yes, there is more glute activation ATG, but it's in the fully stretched state, something you'll never use on the bike. So you're trading performance in the pedal stroke range for performance outside of that range.

Flexibility and risk of injury I'm with you, deeper is better. But for me it's not enough to offset the benefits of heavier, more specific loading.

Most fitness related issues seem like religious or political debates. People just assert things without citing any studies that show it's actually true. And like religion or politics the more dogmatically you assert something the more followers you are likely to attract, even though what you're advocating is nothing more than something you've pulled our of your ass or just decided is true because you figure it is.

Would overused or injured knees be a good excuse? Or is it better to let the hell loose even in that case?

Excellent excuse. Any hindrance to easy range of motion that's not fixable, or takes time to fix, just do what you can. Shallower squats are better than painful squats or no squats. Tune out the ATG crowd.

That said if the flexibility or balance limitation is workable, air squats are great too. Or empty bar or just holding a light barbell or kettlebell in the front rack position.

To be fair I don't think anyone other than powerlifters are using the super wide stance. I'd say "traditional" squat would be high bar, feet close to or just a bit wider than shoulder width, and feet only turned slightly out.

In regards to bigger half squat being better than a lesser full squat. There is probably a point where the discrepancy is so big it's true. But ime anyone with a huge full rom squat has a huge half squat, whereas the opposite is not true.

People also assert things and cite studies that conform to their world view---a few citations does not a defense make. There are as many shit studies as there are Youtube crackpots.

I have extremely long femurs (both objectively and relatively) and limited lower back and ankle flexibility; i'd basically fall over if I tried a deep squat. Any movement should be adjusted to one's physiology and specific fitness goals. I've ultimately found kettlebells and body weight movements focused on range of motion to be a better option than squats at all. My point is, nothing about range of motion should be purely dogmatic ("this is the only correct way"), at best you can come up with guidance and individuals need to adjust (and they aren't "doing it wrong" because they've best tailored to their personal situation).

Sure and that can form the basis of a debate on the strength of the evidence, which is preferable to people just asserting something is true and then arguing on the basis of who knows what.

at the 90* point of the squat - yes the most stress is on the knees. Going ATG is safer because you get to use your stomach as an airbag to assist the lift, with a rebound effect. Run specific training would be single leg squats, or heavy quarter reps for sprinting. Garage strength on youtube has a lot of great videos. Hex bar dead would be safer and more muscle activating with the lower grips.

Long femurs are certainly a disadvantage, you are never going to be an elite weightlifter with them. However, they don't stop a full rom squat being possible, plenty of people with long femurs manage just fine. As for lack of flexibility, my point is if you don't have the flexibility to perform a deep squat (and there is not some medical issue), you probably should be working on fixing that just from a general health and healthy aging point of view. Also some issues like lack of ankle flexibility can be overcome with equipment e.g. weightlifting shoes with a raised heel.

While I think barbell squats and deadlifts are probably the 2 best strength training exercises, you can certainly get plenty strong without doing either. Lunges are great, leg press/hack squat machines also work. Kettlebells and bodyweight exercises can be difficult to get sufficient loading.

So I wouldn't say you have to squat, let alone full rom. However, unless you have some kind of medical issue there's probably no reason you shouldn't be at least able to do a full rom squat.

Not my experience. Generally, it's a person who is still subject to confirmation bias and has simply found a study that fits. They are not rational or interested in a reasoned discussion of the entire depth of the topic...partixularly when that might lead to them being wrong.

Repeating this one, yet again ... it's been a while and some may not know it

I was far out of my element, on unfamiliar and slightly scary ground: the Strength Training area. Two stereotypical muscleheads in spaghetti strap wife-beaters, baggy b-ball shorts with nu-tech weight-belts were doing the Sausage Contest Pre-Game One-Upmanship Dance around the Leg-Press machine.

While Skinny Little Triathlete Boy was taking his turn, they looked over, dumbfounded by how much his Short-Lever Thunder-Thigh Biker Legs could push.

"What do you Squat?" El Bulko #1 asked.

"I dunno? 5? 515? Depends on when I get home from work. About 10 minutes after that"

Ba-dum-DUM!!!

I threw my towel over my shoulder and strutted away like I was their New Hero

****

Now that I'm WFH full-time, I guess I could change that part to "I dunno? 515? 530? Depends on when I get up to run in the morning. About 10 minutes after that" if anyone asks me again?

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"What's your claim?" - Ben Gravy
"Your best work is the work you're excited about" - Rick Rubin

How about you video those quarter way down leg presses