Ever logged countless hours at the gym and still the scale won't budge? I've stared down that plateau before. For weeks, I couldn't figure out why I wasn't progressing, until I zeroed in on six easy-to-miss factors that prevented me from seeing results.

1. I zoned out
I love reading a magazine while peddling away on the elliptical, but I found myself more focused on the latest celebrity gossip than my actual workout. When I realized that 20 minutes had passed and I hadn't even broken a sweat, I knew it was time to change the way I exercised. Now, instead of zoning out, I incorporate intervals into my elliptical workout. I alternate between speeds and resistances. One of my favorite elliptical workouts changes the resistance on the machine every 1 to 2 minutes, which pushes me to work hard for the entire 30-minute duration. Similarly, when running on the treadmill, I pick up the pace by 1 mph during the commercials.

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2. I planned my weekend (via text message)
I used to see the Stairmaster as the perfect place to work and play at the gym. I texted my friends and broke a sweat at the same time. If I put the machine at a slow and steady pace, my hands (and thumbs) were free to see what my friends were up to or plan out my weekend. Looking back on these workouts, I could have worked a lot harder if I had put down my phone! Now, I utilize my iPod to motivate myself through my workouts.

3. I chewed gum
I'm a big gum chewer, so I didn't see anything wrong with popping a piece before starting my cardio workout. I didn't realize that the act of chewing gum prevented me from moving faster. My brain couldn't seem to do both things simultaneously. When I stopped chewing gum during my workouts, I was able to put more of my energy into pushing myself to go faster and farther. And I cut down my risk of choking—an obvious plus.

4. I couldn't hear myself breathing
I exercised in the early morning before the gym got too crowded. I liked working out at this time of day—I had my choice of cardio machines and weights and it was fairly quiet. In fact, the quiet, early-morning hours made me realize that I probably wasn't working hard enough. The only thing I heard was the whirl of the cardio machines. If I was working as hard as possible, shouldn't I also hear my breathing? It's not like I needed to grunt like a tennis pro, but realizing that I wasn't breathing heavily made me want to pick up the pace!

5. I did the same routine
Looking back, it's no wonder I didn't make any progress in the gym. I did the same exact workout from week to week—I didn't increase my pace on the elliptical, I didn't run farther on the treadmill, and I didn't lift more weight or do more reps when strength training. My body got used to doing the same exercises over and over, so I didn't see any changes. Now, I like to switch things up every week. Plus, changing my routine keeps me motivated!

6. I spent too much time chatting with my workout buddy
Making a gym date with a friend is a great way to motivate yourself to work out. But when I spent most of my workout chatting with my buddy, I realized our gabfests distracted me from the real reason I was at the gym—to exercise! Now my friend and I head to a class together and keep quiet (we don't want to be shushed by the instructor) and we save our gossip session for the locker room.

Read Tina's daily food and fitness blog, Carrots 'N' Cake.