The spread offense has become the dominant philosophy across most of football. For years the game was about moving big, powerful people around to create angles and advantages at the point of attack but specialization and skills development have led to the forward pass becoming the dominant aspect of the game.
It's hard to have the strongest and most powerful team, especially if you're a program at the high school or collegiate level that doesn't have access to a wider talent pool. However, lots of teams can find a quick-thinking leader who can fling the ball around. Eventually the bigger programs in college football also realized that putting their speedsters in space only helped their cause and even helped their run games. As a result, now you only tend to see bigger, pro-style formations forming the basis of the offense for schools who's talent pool primarily consists of big, powerful people.
Now that the spread has proliferated across multiple leagues there is a ton of variety to the systems you see on a given Saturday. This is going to be an attempt to try and categorize some of the main schools of spread offense that have developed and to describe their philosophies of how to use spread formations to score points.
Tempo and formations won't factor as much into these breakdowns as virtually every spread offense in existence will utilize tempo and some of the same formational tactics in order to create the spacing and stress they want.
Papa Air Raid
The Air Raid put "the spread" on the map in a major way. When Hal Mumme was whipping defenses at Kentucky and Mike Leach was dropping 70 on people out in Lubbock it caught a lot of attention from eyeballs across the country. Most college coaches and power programs dismissed it as "finesse" offense (which it was) and continued to focus on systems that would allow them to run the ball down people's throats.
But high schools (especially in Texas) and other smaller programs embraced the system as a way to gain a marginal advantage and it ended up becoming the dominant strain in the Big 12. Today half the Big 12 runs a variety of Air Raid offense and two more run a system that's been influenced by the Mike Leach coaching tree (Texas and Baylor). Every school in the league runs a spread.
The original Air Raid was basically taking the West Coast passing game, simplifying it to a purely conceptual level, and then making every formational and personnel decision around maximizing those passing concepts. So Leach would use wide OL splits to help buy time for his QBs to make full field reads, he'd choose tall, heavy OL that were good at being obstacles, and he'd flood the field with fast, sure-handed receivers.
The modern versions of the Air Raid have tended to mute the wide splits and overly pass-heavy emphasis of the original Air Raid. Run/pass options (RPOs) and dual-threat QBs have been a major boon to the system and allowed teams to get enough out of their running game to be balanced and stop defenses from embracing the same kind of extreme, pass-focus to stop them.
TCU under Trevone Boykin is a fantastic example of what the offense often looks like now, there's still a major focus on flinging the ball around but with outside zone and QB option mixed in to provide some balance.
Main strategy of the Air Raid
As Mike Leach put it, "we want to throw it short to people who can score."
Perhaps what really made Leach's Air Raid take off was when they mastered the 4-verticals passing concept and could tag receivers to run stop routes or comebacks if they found open grass:
This approach really got going with Rich Rodriguez at West Virginia but is also a good way to characterize the offenses at Oregon, Hugh Freeze's Ole Miss system, and what Urban Meyer was running at Utah and Florida.
Spread-option teams are "spread to run" squads but they aren't looking to smash people out of the paths of their runners but use conflicts to out-leverage them. The zone read play was one of the initial means to achieve this goal but now teams have a wide variety of QB option schemes and RPOs to allow them to put conflict on defenders all over the field and "hit em where they ain't."
Some of these teams could thus be described as "spread to run" teams but are also "finesse spreads" in that they often aren't very physical at the point of attack. Oregon for instance does not usually field linemen and backs that can bowl over the depleted numbers in the box, instead they'll use outside zone and screening techniques to open up creases. Ole Miss runs zone and power schemes but they aren't very physical at the point of attack either, instead relying on leverage created by spacing and putting defenders in conflict with the option.
Main strategy of the spread-option
To put defenders into conflict and distribute the ball wherever leverage advantages result.
The zone read with outside zone blocking and a backside bubble screen is a favorite way Oregon uses to put maximal horizontal stress on an opposing defense:
The smashmouth spread
There's a lot of overlap between these varying philosophies and in particular between the "spread to run" schools of spread-option ball and the smashmouth spread. The difference with this school is that these teams are all about using lead/power run games to be physical at the point of attack in order to set up play-action shots down the field.
Urban Meyer's system has evolved at Ohio State from the spread-option school into the smashmouth spread school as he's found that with midwestern OL it makes sense to take advantage of a spread out defense by running over isolated targets.
There are a few schools and coaching trees within the smashmouth spread that are fairly distinctive from each other and have evolved out of different approaches. First there's the Gus Malzahn school, which came largely out of the Wing-T tradition, and combined QB option with the power run game. Chad Morris is another coach within this school who puts perhaps a greater emphasis on the play-action passing game.
Then there's Dana Holgorsen, who came from the Air Raid tradition but started to emphasize formations like the "diamond" and the "spread-I" in order to get a two-back running game that would set up play-action down the field.
Finally there's the Art Briles school of offense that I call "the veer and shoot." The Air Raid followed the idea of "what if we designed an offense to be phenomenal at the passing game and milked it for all it's worth?" The Briles veer and shoot takes the idea of a power run/play-action spread offense to its logical extremes.
The WR splits make for intense spacing, the passing game focuses on attacking deep or wide with screens and vertical routes, and the run game is filled with down blocking angles and two-back lead runs. Even the personnel are chosen for their extremes, veer and shoot teams target the biggest OL and the fastest WRs they can find so that teams are really punished for failing to use numbers to stop either the passing game or the runs.
Main strategy of the smashmouth spread
Isolate and overpower weak spots.
The power run from a three-WR set:
The pro-style spread
Then there are the teams that want to run pro-style concepts but love the way in which going up-tempo and spreading out your opponent makes everything easier. As Alabama has found under Lane Kiffin, RPOs are like WD40 for a simple zone running game.
There are major spread elements present in the NFL today, because it's usually the best way to isolate match-ups which is what the pro game is all about, thus you're now seeing it at traditional power programs in the college game.
The good pro-style spread teams are concept based, like the Air Raid, and try to do a few things really well. The bad ones try to mix in spread formations and concepts with pro-style language and approaches, call themselves "multiple," and are inefficient at most everything.
It's very difficult for college teams to actually be really, really good at multiple comprehensive concepts. The amount of practice time and the versatility or roster depth necessary to be balanced between the run and pass is usually beyond most programs. You see this most prominently at tight end.
The best tight ends you've heard of are usually just okay run-blockers and great receivers. Then there are tight ends who are great blockers but aren't typically awesome receivers. The challenge of the pro-style spread is usually how to run the ball effectively from formations with a TE if the TE isn't actually a good run-blocker.
The answer has essentially been the RPO game, which is why nominally pro-style teams are now embracing spread formations and tactics. If you can combine your drop-back West Coast passing staples with your zone or power run game on the same play you simplify protections and you put much less burden on your TE to be a master of both blocking and route-running.
Main strategy of the pro-style spread
To use spacing, tempo, and options to augment both pro-style run and pass concepts in a balanced attack.
Dropback passing concepts like Y-stick and curl-flat combined and run from a spread formation.
Those are the main schools that dominant spread systems across the college football landscape. Did I leave any out?