Every personal trainer or fitness instructor has a story about something they wish a client or class participant would do differently—use deodorant, brush teeth, wear a more supportive bra…

Personal hygiene and wardrobe malfunctions aside, a health and fitness professional’s insider perspective could help you perform better and get more results—and enjoyment—out of your workouts. Here are four disclosures that your personal trainer or fitness instructor wants you to know, but might not come right out and say.

1. Don’t Be Late If You Can Help It

You might think that popping into a fitness class 10 or 15 minutes after it’s started, or arriving to a training session well behind schedule, is no big deal because only you miss out, right? It's not just about you, though.

Your tardiness in group exercise is disruptive to the other people in class and distracting to the instructor. Plus you don’t get to properly warm up, which can hamper your performance and increase your risk of injury. This is what’s going through your instructor’s mind as you slip in late.

Even though you still get to warm up when you’re late for a personal-training session, it’s not ideal. Your trainer likely had a program mapped out for whatever allotted time you were supposed to be together. When you unexpectedly show up late, your trainer has to either figure out on the fly how to cover the program in less time or mentally scramble to come up with a modified plan. 

2. Your Facial Expression Says It All

Demanding more from your body than it’s used to doing can feel uncomfortable—but it’s how you progress with fitness. Still, sometimes clients and fitness participants try to avoid the discomfort of vigorous exercise by going through the motions of a movement without really pushing themselves. Guess what? Trainers and instructors are well aware.

Luckily, many clients/participants display a clear and immediate “tell” about their true effort: facial expressions. When people work hard and are focused on an exercise, you can see it on their faces: they look like they’re concentrating, and they might grimace or grit their teeth. Trainers/instructors search for cues such as these to help determine if you’re going for it, faking it or simply need more of a challenge.

3. If It Doesn’t Feel Right, Speak Up

With the above said, no trainer or instructor wants you to grin and bear it when something doesn’t feel right or is just plain painful. There’s a difference between challenging yourself and hurting yourself. If a trainer asks you to do an exercise that feels “wrong” for your body or as if you’re going to do damage, say something. In a fitness class, modify as needed and then let the instructor know after class so you can discuss alternatives for next time.  

4. Energy Flows Both Ways

As a client or class participant, you likely appreciate a personal trainer or fitness instructor with good energy—it helps you get motivated for the workout! But the flow of energy goes both ways, and this is what health and fitness pros want you to know.

A client who complains constantly or always mopes around the gym will eventually zap a trainer’s energy. Fitness class participants who appear completely unenthused do the same to an instructor. While it’s a health and fitness pro’s job to set an upbeat tone for the workout, a client’s attitude can either heighten or hinder the overall experience.