Anyone who ever said personal training was an easy profession was never a certified personal trainer. Being a skilled fitness professional requires significant education and training, planning, communication skills, expertise with exercise technique and assessments, risk management, sophisticated organizational skills, and flexibility (in more than just the physical sense). That said, sometimes things can still go awry during a session. And, it might not be the result of poor planning or a frenzied day. Fitness professionals are human too and we make mistakes and wrong turns just as other professionals do.

Here are seven common mistakes to avoid in your practice:

1. Forgetting to document

Documentation is of the utmost importance. Thinking that you’ve got it all in the back of your head is one of the mistakes that many seasoned trainers make. However, in order to make modifications, know when to progress, or identify a client’s areas of struggle or success, careful notes must be taken during each session. Avoid focusing only on the “science-y” notes – the reps, the sets, the exercise modes, etc. Be sure to document comments the client makes such as, “I’m stressed at work” or “I don’t like this exercise”. These anecdotal notes are important for you to be able to connect with the client on a personal level and fully engage with the events of their life and the qualitative experience of their session with you. Additionally, carving out time to reflect on those notes before the next session allows the fitness professional to make a solid plan for the next workout and serves as a reminder to the fitness professional to ask follow-up questions about whatever significant events the client shared previously.

2. Focusing too much on the conversation

Fitness professionals tend to be “people” people. We love to chat with our clients and make meaningful connections by building rapport. However, we need to strike a balance between conversing too much and conversing just enough. Doing too much side chatting detracts from the session and pulls the focus off of the work to be done. Carve out time before or after the workout to touch base on the small talk. 

3. Not varying program design

Here’s where we can start to see a client plateau or experience regressions in their progress or develop an injury. The process of periodization will help you engineer the right structure and provide specific points during the training cycle to make necessary changes, advance exercises, modify the rep scheme, or switch up the mode of exercise. Anticipate that every client has the potential to burn out or reach a stalemate with regard to their exercise regimen. Integrate thoughtful and intentional changes before a client exhibits boredom or their progress halts.

4. Varying the program design too much

Variety is great. It is what makes a program unique, fun, and effective. However, changing the program too much, too frequently has its downsides and one of those mistakes that can be avoided with some attention. Making every single workout completely different from the last doesn’t allow for adequate time for physical adaptations to occur. As a result, a client will likely not experience progress – or not the type of progress they so desire. Again, periodization can help you avoid this landmine and strike the perfect balance when it comes to the frequency of alterations. For the client who gets bored easily and insists they don’t want to do the same exercise twice, explain the concept of adaptation, and then “trick” them into similar movements that are just different enough from the last session’s moves.

5. Thinking “hard” is good

Clients need a challenge; the body needs to be consistently overloaded in order to make meaningful adaptations. We can do this with a thoughtful approach and while considering the likes and dislikes our clients communicate to us. There’s a difference between an exercise being “hard” because the client is being challenged beyond a previous physical threshold and an exercise being “hard” because the client despises the activity. There’s also a lot of risk and less reward (with regard to achieving goals) to leaving a client on the floor heaving in a puddle of sweat at the end of every session. Choose activities and exercises wisely and in cooperation with each client so that you demonstrate your caring regard for their preferences and needs.

6. Not aligning a program with client goals

This “sin” has two parts. The goal itself (and the type of goal) and program alignment with that goal. First, developing physical fitness should be goal-driven but not only based on a specific outcome. For a program (and the personal training experience) to be valuable and effective, fitness professionals need to help clients identify process goals (i.e. eating four servings of fruits a day; committing to exercise three days a week, etc.) in addition to outcome goals (i.e. weight loss, muscle “tone”, etc.). In other words, a client expresses their desire to lose an arbitrary amount of weight.

There is value (and health benefits) to that outcome. But the questions to ask relate to the “how” the outcome is achieved. How will weight loss occur? What behaviors underpin the process of achieving weight loss? Here, we need to probe a little deeper and help uncover existing behaviors that may be preventing the client from achieving the outcome or sabotaging their otherwise well-intended efforts. Second, once those behavior goals are identified, the program the fitness professional develops must align with and support those goals. Check in with the program design and determine if the design supports the process and the outcome.

7. Favoring additional reps over form

It occurs in every exercise session – a breakdown in form when fatigue sets in. While you might want the client to perform three sets of 12 repetitions of a lunge, but the client – on the last set, starts to lean forward or fall to one side. At this point, stop the exercise. Document it. Move on to the next exercise. It could be the client needs more rest between sets to hit the 12 rep goal.

Always prioritize form and function over a predetermined number of reps and sets. When form starts to deteriorate, the body tends to compensate by relying on other parts of the kinetic chain to “get the job done”. This can lead to injury and the client will not reap the total intended benefit of that specific movement. Keep the form in check and cue often.

Personal training is a tough business. Mistakes are going to happen. That’s ok – it doesn’t mean you are “bad” at what you do or that you won’t succeed. It just means pressing the pause button and reflecting on your practice and ensuring you work hard to avoid the biggest landmines and most common mistakes.

Erin Nitschke

Dr. Erin Nitschke, NFPT-CPT, NSCA-CPT, ACE Health Coach, Fitness Nutrition Specialist, Therapeutic Exercise Specialist, and Pn1 is a health and human performance college professor, fitness blogger, mother, and passionate fitness professional. She has over 15 years of experience in the fitness industry and college instruction. Erin believes in the power of a holistic approach to healthy living. She loves encouraging her clients and students to develop body harmony by teaching focused skill development and lifestyle balance. Erin is also the Director of Educational Partnerships & Programs for the NFPT. Erin is an editorial author for ACE, IDEA, The Sheridan Press, and the Casper Star Tribune. Visit her personal blog at