50lb bag of sand. Ever get hit by one? Check out this RB comparison

[CodyJ.]

50 lbs isnt a huge amount of weight. Most of us can pick up a 50lb bag of sand. Now throw that bag of sand at somebody as hard as you can. It's taveling at about 5mph. bet it'll move ya. Would a 5olb bag of sand traveling at 5mph move a 300lb DL?
Now im going to get all Engineer on you:
Martin Hyppolite -
Mass=216lbs 40 yard dash = 4.45seconds Intial acceleration (1st 10 yards)= 6.07yds/s^2
F=ma---> 537Newtons of Force

Lyle McCombs-
Mass=166lbs 40 yard dash = 4.46seconds Intial acceleration (1st 10 yards)= 6.05yds/s^2
F=ma---> 413Newtons of Force

The difference is 124Newtons of force.
Now back calculating---> 124N = 50lbs @ 12.6mph.
If I threw a 50lb bag of sand at 12.6mph at you, would it move you? Would it move a 300lb DL?
Better yet, take that extra 124Newtons away, now you have Lyle McCombs inbetween the tackles. He's not going anywhere. Not falling forward. Not anything.

Interesting is that they both have the same initial acceleration and same 40 time. both can get to the corner at the same speed. BUT, if you KNOW there is going to be contact(up the middle) you absoluetly need to have more force moving forward. It's in the math.

 

[ktuck911]

nice scientific synopsis... Now how does this help our running game?

 

[Jimmy Serrano]

First, those are fabricated 40 times. Second, nice little analysis....but can the kids play football? There's a reason the fastest Olympic sprinters don't play in the NFL.

 

[CodyJ.]

First, those are fabricated 40 times. Second, nice little analysis....but can the kids play football? There's a reason the fastest Olympic sprinters don't play in the NFL.

40's are not fabricated. they are both their top 40 times.

 

[CodyJ.]

nice scientific synopsis... Now how does this help our running game?

it doesnt. it just puts proof to the theory that McCombs between the tackles wont work well

 

[Jimmy Serrano]

40's are not fabricated. they are both their top 40 times.

Yeah they run 4.45's....except when they run in the combines it's a 4.65.

Are you saying both of them are as fast as Kashif Moore?

 

[pj]

More relevant is how long it takes a hit to stop the player. According to one site, http://www.faqs.org/sports-science/Fo-Ha/Football-Mass-Momentum-and-Collisions.html, the hit from a linebacker on a running back is about 1000 pounds or a deceleration of 4 times the acceleration of gravity, or about 40 m/s^2. For a player running at a 4.45 40 or 8 m/s, or a stopping time of 0.2 seconds, in which case he'll have traveled 0.8 meter = 32 inches during the collision. That's for Hyppolite. McCombs weighing 3/4 as much will progress 3/4 as much = 24 inches after contact. So Hyppolite picks up an extra 8 inches due to his extra mass.

That's if they're equally good runners. If McCombs is a better runner he might pick up more than that 8 inches, eg by evading a head on collision.

 

[CodyJ.]

Yeah they run 4.45's....except when they run in the combines it's a 4.65.

Are you saying both of them are as fast as Kashif Moore?

lemme go get the source and post it for ya. i was surprised too.

 

[Jimmy Serrano]

lemme go get the source and post it for ya. i was surprised too.

Don't worry about it. I'm sure those are their reported times. I'm just saying they aren't close to being accurate.

 

[CodyJ.]

More relevant is how long it takes a hit to stop the player. According to one site, http://www.faqs.org/sports-science/Fo-Ha/Football-Mass-Momentum-and-Collisions.html, the hit from a linebacker on a running back is about 1000 pounds or a deceleration of 4 times the acceleration of gravity, or about 40 m/s^2. For a player running at a 4.45 40 or 9 m/s, or a stopping time of 0.2 seconds, in which case he'll have traveled one meter during the collision. That's for Hyppolite. McCombs weighing 3/4 as much will progress 3/4 meter after contact. So Hyppolite picks up an extra 9 inches due to his extra mass.

That's if they're equally good runners. If McCombs is a better runner he might pick up more than that 9 inches, eg by evading a head on collision.

a hit from a linebacker coming full speed is definitley a factor. I was thinking more along the lines of running into the pile and bouncing off of DL's

 

[uconndogs]

I watch a lot of college football and I probably saw 90% of the plays Donald Brown and Jordan Todman took from scrimmage. Neither McCombs or Hypolite have that speed and both Brown and Todman clocked in the 4.4s at their respective combines. Maybe they've run those 4.4s, but it just doesn't translate onto the field to my eye. With that said, Hypolite got around the corner last week and outran a bunch of folks. I would not be at all surprised if his straight line speed is superior to McCombs.

 

[ktuck911]

it doesnt. it just puts proof to the theory that McCombs between the tackles wont work well

Kinda figured as much... more fodder against the coaches' decision making on how much our back up RBs are involved ( or not )...

 

[CodyJ.]

These numbers are based on a straight line and amount of force. Regardless if the 40's are correct or not, the two kids are comprable in speed according to the web. The difference in force is 124N regardless if they both ran a 5sec -40.
The difference is what is the factor here. not the overall values.

 

[UCername]

Deleone > Newton, it's science

 

[businesslawyer]

Have I ever been hit by a 50 pound sack of sand? No.

Do I assume there are people in the Boneyard who would hit me with one given the chance? Heck yes.

 

[Jimmy Serrano]

Have I ever been hit by a 50 pound sack of sand? No.

Do I assume there are people in the Boneyard who would hit me with one given the chance? Heck yes.

LMAO. I'm not one of them, but you do seem to draw a crowd who for whatever reason just hates everything you write.

 

[CTMike]

Have I ever been hit by a 50 pound sack of sand? No.

Do I assume there are people in the Boneyard who would hit me with one given the chance? Heck yes.

This could be one heck of a fundraiser. Sort of like a dunk tank, just way more painful.

 

[IMind]

First, those are fabricated 40 times. Second, nice little analysis....but can the kids play football? There's a reason the fastest Olympic sprinters don't play in the NFL.

Because they don't have football in Jamaica?

 

[J187Money]

LMAO. I'm not one of them, but you do seem to draw a crowd who for whatever reason just hates everything you write.

Why do you think I didn't point him out to the people that came looking for him in 241? Wasn't sure of their agenda lol.

 

[pj]

a hit from a linebacker coming full speed is definitley a factor. I was thinking more along the lines of running into the pile and bouncing off of DL's

If the linebacker is running at the same speed as the running back, then the linebacker will reverse the running back immediately and drive him backward. But that rarely happens. Usually the running back has more momentum than the linebacker.

 

[Carl Spackler]

Cody - you left out the most important thing in body contact in football - leverage.

Your F=ma center of gravity player vectors look like this:

→←


But it's actually a very rare thing when something like that happens in football, it's almost always one player lower than the other, and almost always some kind of angle involved in 3-d space, not parallel head to head, and there's a lot that can happen to make a lighter mass, overcome a heavier mass in those circumstances, after an impact.

D →
← O

OR

← O
D →

That old term you hear Gruden talking about on ESPN national TV - pad level.

Being shorter as a TB - is desireable simply because it's harder for a defender to get low enough on the tackles to change the momentum easily. Don't see many 6'1"+ running backs at the highest levels. The difference between guys like Ray Rice and Lyle McCombs - is absolutely right on the money Cody - about the equivalent of a 40-50lb bag of sand. Without that bag of sand, even with the lower contact position, very very hard for an offensive player to generate continued forward motion after getting contact, a guy like McCombs, is fighting to hold his ground, not to gain more ground against much heavier defenders.

 

[Carl Spackler]

There may even be one or two who would prefer the bag be filled with gravel.

I think the gravel, batteries, nails and such are reserved for me.

 

[FfldCntyFan]

The board's beginning to get its sense of humor back!

I see this as a good thing.

 

[husky210]

50 lbs isnt a huge amount of weight. Most of us can pick up a 50lb bag of sand. Now throw that bag of sand at somebody as hard as you can. It's taveling at about 5mph. bet it'll move ya. Would a 5olb bag of sand traveling at 5mph move a 300lb DL?
Now im going to get all Engineer on you:
Martin Hyppolite -
Mass=216lbs 40 yard dash = 4.45seconds Intial acceleration (1st 10 yards)= 6.07yds/s^2
F=ma---> 537Newtons of Force

Lyle McCombs-
Mass=166lbs 40 yard dash = 4.46seconds Intial acceleration (1st 10 yards)= 6.05yds/s^2
F=ma---> 413Newtons of Force

The difference is 124Newtons of force.
Now back calculating---> 124N = 50lbs @ 12.6mph.
If I threw a 50lb bag of sand at 12.6mph at you, would it move you? Would it move a 300lb DL?
Better yet, take that extra 124Newtons away, now you have Lyle McCombs inbetween the tackles. He's not going anywhere. Not falling forward. Not anything.

Interesting is that they both have the same initial acceleration and same 40 time. both can get to the corner at the same speed. BUT, if you KNOW there is going to be contact(up the middle) you absoluetly need to have more force moving forward. It's in the math.

I'm not a mechanical engineer. I'm a civil structural guy so I don't claim to be familiar with forces in moving objects. I haven't done that stuff since college/fe exam days, but it seems to me your throwing alot out the window with your math. What about momentum and center of gravity ( where Carl's pad level comes into play) also players tend to prep themselves for hits where they get low and push forward like a spring. This is where lower body strength comes into .

 

[businesslawyer]

I think you've proven that, everything else being equal, you'd prefer to play football with bigger guys.

Gee, thanks.