Running seems easy enough: Just grab a pair of sneakers and put one foot in front of the other, right? Well, anyone who’s struggled to get through a mile or even the first five minutes (yep, we’ve been there) knows it’s not quite that simple. The concept of running for fun or even a social activity can be mysterious. And setting a personal record in a race? That seems like it’s just for the pros.

If you’ve ever considered joining the sweaty, endorphin-fueled tribe of runners but are even the tiniest bit intimidated at the thought of running a 5K or figuring out what the heck a fartlek is, we’re here to help. We asked now-seasoned runners to confess the biggest mistakes they made as newbies to the sport, so you can avoid them as you begin pounding the pavement.

1. Only Running

During my first two months of marathon prep, I didn’t incorporate any other form of training besides running. My legs were constantly sore, and I started to hate running. I realized I needed to run less and incorporate more cross-training into my schedule. —Alyssa Arnold, marathon finisher

2. Not Moving Post Workout

My biggest regret was plopping down on the couch and not moving after my first 10K. My legs got so stiff I could barely walk for a few days, and stairs were torture. I’ve learned to keep the blood flowing by walking, gentle stretching, and foam rolling in the hours after a hard run. It’s really helped my recovery! —Jen Batista, avid 5K and 10K runner training to conquer the half-marathon

3. Eating New Foods Before a Run

I tried a new breakfast the morning of a long run. I forgot to buy bananas for my usual bagel, peanut butter, and banana breakfast, so I improvised. I was cramping after the first 45 minutes and vomited later on. —Christopher Lopez, multiple marathon finisher and co-leader of The Rise NYC

4. Being Too Ambitious

Running Tips

I got excited and signed up for a half-marathon with a few more-experienced runner friends, but I wasn't adequately prepared and didn't train efficiently. I ended up with blisters the size of small children on my feet. I couldn’t wear shoes for two days! —Cali Lavey, recreational runner

5. Forgetting to Take Rest Days

Training too much and not resting enough zapped me for months. I was exhausted, and my stoke levels for running were at an all-time low. I’ve since learned to run, rest, and be patient more than being dramatic and drastic. —Dominic Grossman, professional runner for Injinji

6. Ignoring Your Form

I didn’t do enough form work and strength training until I got a few injuries. Now I actively do a lot of form drills and strengthening of the hips and glutes to balance out my natural tendency to overpronate. —Marnie Kunz, CEO of Runstreet and run coach

7. Trying to Race Every Run

When I first started running, I tried to PR [run a personal record] every time I stepped out the door and do speed work on the treadmill as often as possible. It worked great for a couple of weeks—until I got a stress fracture. —Ron, runner for 14 years

8. Skipping Leg (or Hip) Day

I had IT Band syndrome all through training because I didn't do any hip strengthening. When I tried to keep running with my weak hips, I eventually ended up with a stress fracture in my back. On top of good form, strength training is crucial. —Meredith Harclerode, two-time marathon finisher

9. Believing Your Sneakers Are Immortal

Running Tips Shoes

I only bought one pair of sneakers to train for my first marathon, thinking their shape deteriorated based on how long you owned them, not how many miles you run in them. On my final 20-mile training run, I had so much swelling and pain in my feet I had to stop. After a doctor-ordered MRI, I discovered my sneakers had been “dead” for over a month. I then had a choice: to run the marathon on dead shoes or buy brand new ones. I opted for new shoes, but next time I train for a marathon, I will have a couple of shoes in rotation! —Kate Barry, four-time half-marathon finisher, one-time marathon finisher

10. Refusing to Stop

After weeks of barely being able to run due to IT band pain, I lined up for the San Diego marathon. When I found myself hobbling at a 20-minute per mile slog, I still refused to stop. I thought, “Runners don’t quit; we push through!” As a result of my "powering through" to the finish, I couldn’t run for six months. Now I know that one race or run isn’t worth months of frustration. —Amanda Brooks, eight-time marathon finisher, personal trainer, and author of Run to the Finish

11. Not Fueling Carefully

I ran a military-style race and brought a goo packet along for fuel. It exploded when I opened it mid-race, which made everything sticky and smelling like a sour apple for five miles. Gross. —Lavey

12. Waiting to Get Pain Checked Out

I’ve always been athletic and I’ve never been badly injured, but one day I felt a slight pain in my knee. I ignored it for a month until I realized I was having a hard time putting weight on my right leg. I finally went to a doctor and found out I had an IT band issue. It took four months of weekly physical therapy to heal. I shouldn’t have waited so long to get it checked out. I put a damper on my training, and it ended up taking longer to heal. —Arnold

13. Blindly Following Trends

I bought minimalist shoes without knowing what minimalist even was; I just knew people liked the shoes. What happened? You guessed it: I ended up injured. —User TheRunningTroll on LetsRun.com

14.  Letting Your Playlist Get Stale

Running Tips: Music

Music helps set the pace of your run and makes it more enjoyable. For every race or tough run, I learned I need to update my playlist so I can look forward to new songs that help push me to the finish. Whenever I forget, I can noticeably see my pace and attitude decline. —Arnold

15. Not Hydrating Properly 

I decided to go out for a run during the hottest part of the day. At the time, I told myself that it would be refreshing to sweat a little, but I didn’t bring adequate hydration. I returned feeling completely rundown, dehydrated, and fatigued. If you must go out on a run during unfavorable weather, wear proper attire and bring enough water to keep you feeling strong. —Sarah Robertson, Marketing Education Coordinator at Precor and recreational runner

16. Failing to Switch It Up 

It took me six years to realize that I actually got better at running when I was running longer distances. I started out running shorter distances and wasted a couple years trying to conquer the mile. —User X Trackster on RunningAhead

17. Using the Same Shoes for Every Run

I ran my first and only road marathon in a pair of very structured, overbuilt, and cushioned trail shoes. I had no idea what I was doing, but I thought I needed the extra protection to save my knees. In retrospect, I realize why I felt slow and sluggish! —Joe Grant, Buff USA Ultrarunner

18. Thinking Resting Is Enough

You Might Also Like {{displayTitle}} READ

After experiencing some pain in my right knee during a half-marathon, I took off for a couple of weeks. When I started long-distance training again, I had the same issue. I realized I couldn't fix it by just resting. Now that I know how to stretch properly, most of my IT troubles are fading away. —Mary Rose, recreational runner and triathlete-in-training

19. Not Familiarizing Yourself With the Route

I have gotten lost and misled more times than I can recall, so if something sounds off or looks wrong—especially on trails—go back to where things looked right and start again. —Michael Wardian, runner for Injinji

20. Treating Running Like Other Sports

My biggest mistake was treating running like soccer practice: If I wasn’t exhausted by the end of practice, I felt as though I didn't work hard enough. I’d run all of my runs at 80 percent effort, or the equivalent of what I now call tempo runs. I wasn’t warming up to the pace or cooling down effectively. —User stadjack at RunningAhead

21. Failing to Take Advantage of PR Opportunities

I did not strike when the iron was hot. I was at my peak fitness during a period, and now I regret deeply not trying to PR across the board. —Seth Ariel Green, former Division III collegiate runner

22. Not Valuing Recovery Runs

Recovery runs should be done at an easy, moderate pace. My biggest mistake in my early years of running was doing too many fast workouts and letting individual runs turn into mini races themselves. —X Trackster

23. Forgetting Anti-Chafe Cream

…..especially “down there.” During the Ultra-Trail du Mont-Blanc ultramarathon, I had to use mud in my nether regions. —Wardian

24. Overlooking Safety Measures

I forgot to change the batteries in my head lamp before a race that required me to run in the dark. It cost me a lot of time. —Michele Yates, Ultimate Direction run ambassador

25. Not Having an Exit Plan

I did a long run without a subway card or money and ended up getting stuck in the rain with no way to get home. I had to sit and wait until the rain let up enough to see. Another time, I got lost and ended up running an extra eight miles(!) because I forgot my subway card. —Kunz

READ THIS NEXT: Why All Runners Should Strength Train 34U34 Health Care Promo