Does a Running Back’s Height Affect Performance?

By Joe Leonard

With Derrick Henry’s recent success in the NFL, his first attribute many point out is his 6’ 3 stature that looks almost comical to other running backs. After leading the league in rushing yards in 2020, some are starting to think that the conventional     5’ 10 build for a running back is no longer ideal. I wanted to test this theory amongst running backs across NCAAF and even more specifically, the ACC. 

Besides returning contender Clemson, the ACC hasn’t been considered a threatening Power-5 conference in football. The week one performance from our top 25 teams did not help either. There must be a reason why the SEC and BIG 10 compete for more titles than the ACC and consistently reign superior in bowl games. Could it be the BIG 10’s bigger draw in terms of recruits? Yes. Could it be because there are only 9 teams in the top 75 for strength of schedule? Yes. But is there anything we, as the ACC, can do to compete with our fellow Power-5 conferences on the field? Maybe we can find the answer to this question in the backfield. 

Height vs. Rank

To start, let’s look at the top 25 running backs from 2020 according to PFF rankings and compare their heights. The top four players all have different heights, with two over six-foot and two under, which can be evaluated as height has no real correlation to success. But with PFF having NFL rookie breakout candidate, Trey Sermon, ranked 23rd, let’s see if we can tweak these rankings. 

There are five attributes scouts and coaches look for when dealing with running backs. These five attributes are speed, vision, blocking, ball security, and durability. If we rank these top running backs in each of these categories and take their average amongst the five skills, we will be left with our own rankings. For speed, I looked up the 40-yard dash times of all the players on DraftScout. For ball security, I took the average fumbles per game of every player using ESPN stats. For blocking, PFF had given each running back a pass and run block grade, so I just needed to take the average of those two scores. For visibility and durability, we see some problems. Durability is hard because for the most part, everyone is in that 18 to 22 age range. What I decided to do was see how many years players had left to see how long they could be in the program for. Younger players had an obvious advantage in this category. To get a more accurate ranking, we could weigh in injuries or even injury risk as some websites have provided that statistic. Another bias pops up for visibility. It is hard to rank down-field vision, so for visibility, I subtracted the player’s height from the average height of their team’s offensive line. This creates a height bias which could be very bad for our rankings, but let’s see what these five rankings leave us with.

This Table Shows the Composite Rank of the Top 25 Running Backs in College Football. They are Organized by Height. The Lower Their Composite Rank, The Higher Their Value. The Rank Was Calculated Using the 5 Metrics Spoken About in the Paragraph Above. 

The average height for an NCAA running back is 5’ 10, so we can see from the chart that out of the 11 players over that height, 4 are in the top 5 (The smaller the bar, the better ranking). When we compare our new rankings to PFF’s we barely see any similarities. PFF had App State’s Camerun Peoples ranked 10th, but with our evaluation he ends at number 2. Although their site contains tons of information and resources, you cannot always trust PFF to give an accurate rating of what you’re looking for. 

“Running Back University”

The term “RBU” has been thrown around in recent years and there have been many debates as to who it really is. We are going to use Sports Illustrated’s 2020 article to see if height has anything to do with who reigns supreme. The top three teams are Alabama, LSU, and Georgia. These are all SEC teams, so to get more of a variety, we will also be looking at ranks 8th through 10th, which are Wisconsin, Miami, and Oregon. If we look at these teams’ RB1 since 2014 and their heights, we find something interesting. 

Alabama, also known as the number one “running back university”, has a significantly higher average RB1 height than the rest of the teams. At an average height of 6’ 1, Alabama’s recent history of running backs include Damien Harris (5’ 11), Najee Harris (6’ 1), Bo Scarbrough (6’ 2), and Derrick Henry (6’ 3). All four are in the NFL and over that 5’ 10 NCAA average. If we look at the ACC teams, we notice they are in the bottom two spots. Miami, who is considered the eighth “RBU”, has an average RB1 height of just under 5’ 10 and UVA, who we are looking at just for comparison reasons, has an average RB1 height of 5’ 9.5. This chart somewhat agrees with our hypothesis, but for it to be useful, we need to prove that those top teams have a better success rate. If we look at winning percentage, number of playoff appearances, and number of bowl games all in the last five years, we can come up with a pretty good success rate equation.

From this success rate chart, we can see similar correlations to average RB1 height. Alabama is leading. UGA, LSU, and Wisconsin are still in the top four. The ACC teams are still in the bottom half. From these charts and the “RBU” rankings, we can see that in some cases, height does play a factor. Now that we understand height as a factor amongst all NCAA teams, let’s dig deep on the running backs in the ACC.

Running Backs Within the ACC

In Bleacher Report’s article titled, “Running Back U: The Top 25 Running Back Schools in College Football”, only five ACC teams are mentioned. When we look at the ACC, the average height of starting running backs in 2020 was 5’ 10, with 10 out of 15 teams equal or below that average. The starting running backs should be the ones taking majority of the snaps and performing for a high percentage of the team’s rushing statistics, but let’s see if this is really the case for all heights. 

On top, you see the involvement in the run game for starting running backs across the entire ACC, and below that you see the same statistic for just the Coastal division. Remember that this information is from 2020, so Notre Dame will be included. In both graphs, we can see that the 5’ 8 and 5’ 9 running backs account for significantly less involvement in the run game than their taller counterparts. Besides 5’ 11 in the Coastal, the running backs equal or above 5’ 10 are above the average involvement in the rushing game. Now, this may be because some offenses have a running game focused around their quarterbacks. To see if this is true, we can look at the QB involvement in the run game as well. 

The five teams under the average line all have running backs equal to or taller than that 5’ 10 average. This shows that the teams with the taller running backs are more likely to include those taller running backs in the run game than the quarterbacks. If we only look at teams above the average, which include UVA, Boston College, FSU, and others, we can get an even better understanding on the heights of their quarterbacks and if they have anything to do with their stats as rushers.

As you can see from the graph, quarterbacks do not have that much correlation with height and rushing statistics. Although 6’ 4 quarterbacks have the highest rushing yards and touchdowns per game, if you try to plot a trend line, none will show up. So, although in previous analysis we found a correlation between height and success for running backs, we cannot assume the same measurement for quarterbacks. Overall, the ACC is not known as a running back heavy conference. In 2015, Ben Kercheval, CBS Sports Editor, published an article on Bleacher Report and ranked the ACC 7th out of the ten FBS conferences in terms of running back depth. Could this be because of the smaller frames of starting running backs? More than likely. If the ACC had the pull of players like the SEC and targeted those high profile, taller running backs, it may have more success in the run game. 

Where Does All This Information Leave Us?

Overall, there seems to be a trend in increasing running back height. Out of the top 25 running backs in the 2022 recruiting class, 68% are over the NCAA average height. This is a 12% increase to the 2005 recruiting class. This trend shows that more college scouts are looking towards taller running backs that can run downhill and take longer strides in open space. Personally, I believe that taller running backs would be more beneficial due to the way they can run downhill and their stride length. Typically, downhill runners can hit holes faster and give more hits then take them. They can generate more speed and force into the ground which allows them to create more power in their strides. Stride length also plays a huge part in running. A quality in Olympic sprinters is that they need to be big enough to produce explosive speed. Using greater strides would produce a greater force to sprint out of the backfield.

Now of course there will be many exceptions from our findings. Even if we look at our original ranking system, we saw a bias in age and height. But besides biases in the statistics we used, the running back is seen as somewhat of a dying position in value. Fantasy football players often refer to the running back as the most replaceable player. We can see this trend in the actual game as well. Coaches are looking at mobile quarterbacks that can pass outside of the pocket, but also scramble if needed to. We can see this highlighted in UVA’s offense. Out of the first two games, UVA’s listed quarterbacks accounted for 51% of carries, 53% of rushing yards, and 75% of rushing TDs. These high percentages show that UVA isn’t afraid to put their QB’s out on a designed run or that Brennan Armstrong uses a dual-threat playstyle. The decrease in running back usage over the past couple of years may hint that the position is beginning to fade away from a focal point in recruiting. But even with the possible decrease in importance, the running back is still a position that could dominate a game if they have the physical attributes to do so. From our statistical analysis, we can see that one of those attributes is a player’s height. 

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