Mackenzie Skelly's Record-Breaking 2025 on the Track

Last fall, Mackenzie Skelly burst onto the Inter-Ac Upper School cross country scene as an eighth grader. She won the Inter-Ac championship race by more than 30 seconds and quickly followed that performance up with a nearly 20-second margin of victory in the PAISAA championship less than two weeks later. The Quakers won team titles in both events as a result, and Skelly was named the league’s Most Valuable Runner for her efforts.

As it turns out, the speedy Penn Charter lifer from the Philly suburbs was just getting started.

On Feb. 21 at The Circuit Boston Race, Skelly broke the national middle school indoor track record in the 3k race with a time of 9:37.69. Then, back in Boston at The TRACK at New Balance for Indoor Nationals from March 13-16, Skelly broke two more middle school national indoor marks: she ran the one-mile race in 4:48.97, then later in the weekend secured the top mark in the two-mile event, finishing that one in 10:14.39.

The three record-breaking runs were impressive on their own, and perhaps even more so considering they occurred during Skelly’s running offseason. She swam all winter and remained in great shape, but at the same time she more or less exited the pool after not running competitively for months and casually set three records in which she now stands alone above everyone in the United States at her age level.

“The whole swim season I pretty much was looking forward to track,” Skelly said during a recent sit down on PC’s campus. “I ran a couple of times a week during swim season, but that was mostly for joy and not to train. It was just to keep me satisfied because I love running. 

“Going into the [February] race, I had the record on my mind. The record holder was a girl I looked up to, so I was going in hoping to break that record. While racing I was hitting all of my splits that I needed and executing my plan really well. Then I ended up breaking it, which was awesome.”

Skelly ran one additional warm-up circuit race in Philadelphia between the two Boston events, and her 4:51 time, while approximately a second short of the one-mile record she would be shooting for at Indoor Nationals, felt easy and effortless. With a week to go before heading north to New England again, Skelly was convinced she was armed with the necessary confidence to finish the job.

“The race was crowded, but it didn’t feel that hard,” she said. “It was motivating knowing I was so close to the record in a race I didn’t consider my best. I could only imagine what a really good race might feel like where I ran better.”

Both of Skelly’s parents ran in college and post-collegiately, so perhaps it’s no surprise that Skelly herself has a predilection for the sport. Her mom, Renee Gunning, is a teacher and Varsity Cross Country Coach at Penn Charter who, along with Brian Rosetti (founder of V.O2), carefully devises and coordinates Skelly’s training regimen, prioritizing the longevity of her running career.

“I knew she had talent, but she also had this inner drive and love of the sport,” Gunning said. “We tried to put her in lacrosse, but she’s not really an ‘in-my-space’ kind of kid and was more happy with the individual-type sport. It was obvious pretty quickly that Mackenzie had a very strong little engine. She could just go, go, go, not get tired, and recover very quickly. Mackenzie’s love of the sport, drive and work ethic were even stronger than her ability.”

Gunning said the trickiest part of her daughter’s fast breakout on the track has been managing Mackenzie’s desire to always push herself harder and further. With a still-developing body, it remains critical that Skelly does not do too much and overexert herself before she is able to actualize all of her running goals.

So, the compromise was made to swap the track for the pool for most of the winter, as swimming is a low-impact sport that still offers the resistance training while increasing the lung capacity that Skelly needs. Gunning told Skelly that she was “either going to be a couch potato or swim.” 

“The trickiest thing is keeping her chill,” Gunning added. “She’s done a good job of listening to us. She pushes back every once in a while because she always wants to do more. But she has big goals and knows that she has to go about that in the correct way and not rush things.”

For her part, Skelly understands that she sometimes needs to be reined in while at the same time craving more and more. 

“I think I love the feeling of being proud of myself,” she said.

Skelly said without much more fitness to gain until Indoor Nationals, she instead mentally visualized herself setting the one-mile record. The mile race took place on March 13, and as good of a runner as Skelly is and knows she is, she’s also human and thus felt plenty of butterflies at the starting line. 

“I was trying to control my nerves but also trying to convert them into energy,” she said, “which I could really use to push myself.”

Skelly’s manifestation worked wonders, as her 4:48.97 was the first middle school mile run to ever break 4:50. Gunning said she worried her daughter’s full-out sprint strategy might backfire, but that never happened. “She was on a mission, and she put on a show,” Gunning recalled.

“As I was running, I kept getting more and more adrenaline,” Skelly added. “I was like, ‘Oh, my gosh. I’m doing it. I’m on pace to break this record.’ I just stayed so positive.”

The next day, Skelly returned aiming for more national accolades. Gunning was again concerned as a coach and mother that her daughter could replicate her performance after such a big adrenaline dump. The two distracted themselves by going shopping and keeping Skelly’s preparation the exact same for the longer race. 

Only this time, Skelly did not go all-out for the entire race, instead maintaining a slower pace at the outset and staying behind the leader while waiting for her moment to pounce. With about 600 meters to go, the moment came, and Skelly did not miss. 

“She laid the hammer down,” Gunning said.

“With the last 600, I knew I was going to do it,” Skelly added.”I was just trying to control my kick.”

Some of her Upper School cross country teammates were there to cheer her on in the two-mile, including Alli DeLisi, Michaela Poland, Gwen Hamilton and Marlie Klein — all girls the younger Skelly idolized before she joined the cross country team.

“I’ve always looked up to Alli DeLisi,” Skelly said. “She is one of my biggest idols in the running world. All of them were a great motivation, and I feel like I’ve really connected with them. Running feels like a home to me, and home is where the people are. They have made running feel like an even greater home.”

As for the spring, Skelly is currently finishing up her final season of CYO outdoor track and is thus not running competitively for Penn Charter at the moment. She also plans to compete in some big invitationals via the New Balance circuit, which will keep her plenty busy until fall cross country season comes around.

Now that Skelly has broken three national middle school records, it has only affirmed her belief that she is on the right path moving forward. She will have even more opportunities to excel once she reaches her freshman year, and Gunning said she and Skelly will remain in lockstep on the latter’s training.

“Our goal is definitely the longevity of her career,” Gunning said. “She obviously wants to run at the Division-I level in college and her dream is also to run post-collegiately. She pretty much has it all planned out.”

For her part, Skelly said it would be a dream come true to break NCAA records and even qualify for the Olympic trials in the future. Gunning herself was a two-time All-American runner in college, and it’s quite clear that the apple has not fallen far from the tree in that regard. 

Of course, Skelly is also thrilled to be developing as a record-setting runner at a place like Penn Charter, an institution that always encourages its students to reach for the stars in anything that brings them passion.

“At Penn Charter there’s so many different opportunities to find what you love,” Skelly said. “There’s so many different paths you can take, and no matter which path you take, there’s so much support. After I have a big race, just walking down the hallway there’s always people saying 'good job' to me and supporting me, asking me how I feel. That’s really awesome.”

- Ed Morrone, OPC '04