My Secret to Client Retention: A Case for Affective Periodization

We all know that it is much easier to retain an existing personal training client than it is to sign a new one. You have already presented your value to the client, and thus, the sale has already been made. In order to be a successful personal trainer, we need to keep our clients happy. This is where the idea of ‘affect’ comes into play.

Affect is experienced as a broad response to stimuli which is encapsulated by the bipolar dimensions of positive-negative, good-bad, or pleasure-displeasure (Ekkekakis & Petruzzello, 2000). Affect is something that is always present and can be non-reflective. It is also highly primitive as it appears positive affect can direct us towards a stimulus (e.g. food, sex, sleep) and negative affect can direct us away from a stimulus (e.g. poor taste, attack, pain; Kahneman, Diener, Schwarz, & Foundation., 2003). According to Hedonic theory, people tend to engage in behaviors which cause pleasure and avoid behaviors which cause pain (Kahneman et al., 2003). Therefore, a goal of exercise should be to maximize pleasure during training as this may encourage individuals to engage in future exercise sessions (Brand & Ekkekakis, 2017).

But how do we make our clients happy in the first place?

Well that’s an extremely tough question to answer but I guess you could start by not being a complete dick when your client messes up on their diet. If you’re completely new to personal training and have no clue how to behave, I would direct you to Jon Goodman’s Personal Trainer Development Career website. I personally learned a lot from this website during my first year as a trainer.

For those of you in the trenches who know the basics of civil human behavior, I suggest you focus on the client’s affective responses from their workouts. In the research realm, affect during exercise is largely measured by the Feeling Scale (Hardy & Rejeski, 1989) which is a single-item scale ranging from -5 (very bad) to +5 (very good). This scale has salient implications for coaches to help clients obtain results.

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The Feeling Scale can show the trainer the client’s tastes and preferences to exercise. By adjusting the client’s program to meet their desires, it increases the likelihood that the client will stick to their program. This will help them obtain their desired results and they will put more trust in you as their trainer. This means you are more likely to retain your clients for a longer period of time and receive referrals from them.

In this article, we will first explain how to use the Feeling Scale in the context of aerobic and resistance exercise. We will then introduce affective periodization and compare the pros and cons of centering a program around affect. Finally, we will explore the hypothesis that affective periodization may lead to superior physiological adaptations.

Aerobic Exercise Applications

When having your clients perform cardio, you would ideally randomly administer the Feeling Scale at multiple different time points during the workout. This is probably not feasible for most trainers as clients usually perform cardio alone, outside of their personal training sessions. It would be great if there was some type of mobile application that would randomly prompt the client to record how they are feeling and send this data to the trainer. Unfortunately, I am unaware of any free software that can do this at this time.

To explain how the Feeling Scale works for aerobic exercise, I usually read some variation of this script: “Some people can find exercise to feel good while others find it to feel bad. Additionally, feelings may fluctuate across time. That is, some may feel good and bad a number of times during exercise. On the Feeling Scale ‘-5’ represents the worst you have ever felt, whereas ‘+5’ is the best you have ever felt, and ‘0’ is neutral. When I prompt you, estimate how you feel right now, at this moment.” I adapted this from the original script provided by Hardy and Rejeski (1989).

When recording data, I tend to ask the client to record how they are feeling before beginning their cardio session and every 5-10 minutes during their workout. If the client is engaging in high-intensity interval training (HIIT), make sure they are using the Feeling Scale both during the high-intensity and low-intensity intervals. This will usually provide me with a handful of Feeling Scale responses (more if they are doing HIIT) that can reveal the temporal trends of the client’s affective experience of their workout.

I will have the client repeat this procedure on multiple different cardio machines and then compare the data. Sometimes, you will find their Feeling Scale responses to remain relatively steady across all exercise modalities. Other times, you will find consistently higher Feeling Scale responses for one particular cardio machine. If the latter occurs, it may be advantageous to prescribe the bulk of the client’s cardio on that machine. It still may be good to have the client use different machines as having variety can increase enjoyment and physical activity participation (Juvancic-Heltzel, Glickman, & Barkley, 2013).

You may also learn how long the client should be performing cardio. For example, if you are looking at the Feeling Scale data and notice that after 15 minutes the client’s affective response become less positive, you may want to only have the client do 10-15 minutes of cardio at a time. Remember, our goal as personal trainers is to keep out clients physically active. While 10-15 minutes of cardio is not ideal, it is far better than not performing any aerobic exercise at all. Additionally, you could always prescribe multiple short cardio sessions throughout the day to reach the physical activity guidelines of performing 150 minutes of aerobic exercise per week (Piercy et al., 2018).

Lastly, you may find that the client is better suited for a particular style of cardio. Trainers usually prescribe moderate intensity continuous exercise (MICE), HIIT, or a combination of both. If you prescribe both MICE and HIIT, you can compare the Feeling Scale responses to see if the client is experiencing greater pleasure from one style of cardio. You can then focus the majority of their aerobic exercise regimen around that style of cardio. Additionally, as there are infinite ways to structure a HIIT workout, you may be able to use the Feeling Scale to find out what work to rest ratio the client likes the most. For example, you may find higher Feeling Scale responses working with a 1:3 work to rest ratio rather than a 1:2 ratio.

At this point, you may be asking: “why can’t I just ask the client what they prefer to do?” Yes, you can and absolutely should ask your client what they prefer. However, people are notoriously poor at rating their affective memory of an event (Kahneman et al., 2003). This is largely from what we call recall bias (Hassan, 2006). Therefore, I think it’s most appropriate to administer the Feeling Scale during exercise. In fact, the affective responses experienced during exercise seem to be a stronger predictor of physical activity participation that the affective responses experienced after exercise (Rhodes & Kates, 2015).

Resistance Exercise Applications

With resistance exercise I usually ask for the client’s Feeling Scale rating before beginning their workout and then immediately after each set. I then add this information to an excel spreadsheet along with their sets, reps, load, and rating of perceived exertion for each lift. As affective responses seem to become more positive with time (Benites, Alves, Ferreira, Follador, & da Silva, 2016), I tend to sit on this information for about a month or so before I start making adjustments to the client’s training program.

This data will provide valuable information about exercise selection, rep ranges, loads, and intensities. In practice, you may find that the client feels better with heavier weights, and therefore, choose to focus their training regimen around building strength. You could also find their Feeling Scale responses to be lower for some specific exercises and choose to eliminate these exercises from their program.

I use a slightly different script to explain how the Feeling Scale works in the context of resistance exercise: “Some people can find exercise to feel good while others find it to feel bad. Additionally, feelings may fluctuate across time. That is, some may feel good and bad a number of times during exercise. On the Feeling Scale ‘-5’ represents the worst you have ever felt, whereas ‘+5’ is the best you have ever felt, and ‘0’ is neutral. After the completion of each set, reflect about how you felt during the set and estimate how you felt.” This may be a less effective way of measuring affect as the client must reflect about how they felt after completing the set. Due to a phenomenon known as ‘affective rebounding,’ most people tend to feel better after finishing exercise (Ekkekakis, Parfitt, & Petruzzello, 2011). For this reason, the affective responses you record during resistance exercise may be slightly inflated.

Notes About the Feeling Scale

In my experience, the affective responses from exercise will be predominantly positive unless the client is engaging in near-maximal intensities of exercise. Therefore, a trainer should expect to look for changes that are roughly 0.5-2 units more positive on the Feeling Scale. While this may sound small, it has been shown that a one unit increase on this scale corresponds to 38-41 additional minutes of physical activity per week (Williams et al., 2008). This translates to roughly an additional 2,080 minutes of physical activity per year!

When analyzing the Feeling Scale data, you need to account for how your client felt before the workout began. Your client is doomed to have bad days which will influence their affective responses during exercise. At this time, I do not know of any easy and effective way of correcting for baseline affect. There are some statistical methods out there but I believe these would be too complicated for personal training. To account for baseline affect, I recommend periodically looking for outliers in the data and simply looking to see if their baseline affect can account for the discrepancies. For example, if you find your client is usually at a +3 for squats but one day is at a +1, you can refer back to how they felt before the training sessions. The day the client was only at a +1 for squats, they may have simply began the training session 2 units lower on the Feeling Scale. So, they simply found less pleasure from that workout than usual.

Overall, baseline affect shouldn’t be something you will have to worry too much about. This is especially true if you do in-person personal training as the presence of a personal trainer should help to stabilize the client’s affect. Outliers will show up in your data but I think it is pretty easy to spot them. You can then refer back to the client’s baseline affect to see if this can account for the outlier.

Pros vs. Cons: A Case for Affective Periodization

I often experience resistance from other personal trainers when I talk about how they should consider using the Feeling Scale during their client’s sessions. In fact, I myself would have probably disregarded the Feeling Scale during my first year as a personal trainer.

In short, most personal training clients are looking to lose fat and build muscle. These are not easy results to obtain. This can be seen by the high rates of obesity in industrialized nations (Bleich, Cutler, & Murray, 2008). Therefore, many personal trainers try to push their clients to their physical limits. The trainers know that the client is most likely not working out super hard (if at all) on their own. So, the trainer needs to try to burn as many calories as possible in their training session. This usually involves using a high intensity style of training. Think about doing wind sprints until someone pukes, burpees until a kid passes out, and then heavy squats until everyone is lying on the floor in pain.

The problem is, this style of training seems to not be pleasurable for most people (Ekkekakis, Parfitt, & Petruzzello, 2011). Now don’t get me wrong, this style of training works for some people. Some people out there truly like to push their bodies to their physical limits. Additionally, there are many people out there who have seen terrific body transformations by engaging in high intensity exercise.

The problem is, most personal training clients don’t want to exercise at these super high intensities. They may tell you that they liked their training session after finishing. They may even work with you for a while and see some good results. The problem is you will eventually burn them out. They will leave you and resort back to their sedentary life styles and poor eating habits.

This is where the personal training industry has failed significantly. Our job is not to create significant body transformations. These transformations are really hard to do and are rarely sustainable (Dombrowski et al., 2014). Our job is to get our clients to be physically active. This seems to be the best thing a person can do for their health. If an obese client can lose just 10% of their initial body weight and stay physically active, they will receive many of the health benefits as having one of these terrific body transformations (Goldstein, 1992). Additionally, it will come without the psychological stress of extreme weight loss.

This is where affective periodization comes into play. Affective periodization is the process of centering an individuals training regimen around pleasure and enjoyment. In this style of training, you let affect be your muse in the structure of your programming variables (e.g., exercise selection, volume, load, tempo). I have had the opportunity to review a good amount of literature on the effects of exercise on the human body. What I have concluded is that everything basically works. Yes, some ways are more optimal than others but at the end of the day, some exercise is better than no exercise.

In sum, affective periodization is a way of playing the long game in personal training. You will not see a large decrease in body fat from your clients in their first couple of weeks. You may even lose some clients as they believe their lack of results is your fault. However, it is my opinion that you will have a greater likelihood of having long term success with the client. I have slowly switched to this style of coaching over the last couple of years and am pleasantly surprised by the results.

Can Affective Periodization Further Training Adaptations?

At this point, you have pretty much finished reading the article. You should now understand why affect is important and how to use the Feeling Scale to try and create more pleasurable workouts for your clients.

Now I would like to ‘geek-out’ and explore the possibility that having a more positive affective experience of exercise can further physiological adaptations. This may sound far fetch as we know that to some extent, higher levels of effort seem to yield better physical adaptations (Fisher & Steele, 2014). If your client doesn’t enjoy training with a high intensity of effort, you may think that they will not receive the most optimal adaptations.

This is not necessarily incorrect but I do have a couple of counterpoints I would like to make. First, everything comes down to adherence. Since experiencing a more positive affective response during exercise leads to greater exercise participation (Rhodes & Kates, 2015), it is possible that focusing your clients program around pleasure and enjoyment will lead to greater adherence. If they are adhering to your program, they should see great results!

My second point is that it is possible that there is a relationship between feeling better during training and the muscular adaptations that are seen as a response from training. When thinking about ways to enhance adaptations from training, we have to consider the huge amount of variability in adaptations that are seen across studies. Evidenced-based training recommendations have been made based off the average response across a group of individuals. While most people probably will respond best to these recommendations, there are numerous outliers and your client may be one of them. For more information on the wide range of responses that are seen in research, I direct readers to this article written by James Krieger and Brett Contreras.

It is my belief that affective periodization, or centering training around pleasure and enjoyment, may be one way of figuring out what type of training your client responds best to. I do believe affective periodization is probably not optimal in the short-term but it may win out in the long term. At this time, I can only provide metatheoretical support for the hypothesis that feeling better during training leads to superior gains. As I am a big advocate of resistance exercise, I will focus on the increases in muscular size and strength. Below, I have described five research examples that provide some support for why I think it is possible that this link exists.

  1. There is a large body of research in neuromotor control which shows that giving a person more choices and the autonomy to choose whichever choice they desire increases their ability to learn (Sanli, Patterson, Bray, & Lee, 2012). If strength is a skill that requires us to learn a specific movement, it can be theorized that giving people the autonomy to choose specific aspects of their training will increase their levels of strength. I tend to draw a connection with autonomy and affect based on research that has shown people to experience a more positive affective response when exercising at a self-selected intensity rather than a prescribed one (Rose & Parfitt, 2007). This relationship seems to hold true even when the two intensities are the same (Hamlyn-Williams, Freeman, & Parfitt, 2014).

    One study showed that giving an elite athlete the autonomy to choose aspects of his practice conditions led to greater performance than when he was prescribed the practice conditions (Halperin, Chapman, Martin, Lewthwaite, & Wulf, 2017). In the first part of this experiment, an elite male kick boxer completed a control and experimental condition. In the control condition, the researchers had the participant perform 12 maximal effort punches using four different techniques (lead straight, rear straight, lead hook, and rear) in a specific order. In the experimental condition, the kick boxer performed the same number and type of punches but was able to perform them in any order that he desired. This study found the kick boxer to punch with greater velocity and force when given the autonomy to choose the punching order. In the second part of this study, the researchers confirmed these findings among a group of 12 amateur kick boxers. This shows that giving a person more autonomy (which may lead to a more positive affective response) leads to improvements in performance (or possibly maximal strength in the context of resistance exercise).

  2. We have evidence to suggest that two of the exact same workout regimens do not yield equivalent results when a person is given the autonomy to choose which workout to perform on which day. McNamara and Stearne (2010) compared the effects of a flexible nonlinear periodized resistance training program versus a nonlinear periodized resistance training program on changes in strength over the course of 12 weeks. This experiment showed that giving participants the flexibility to choose a 10, 15, or 20 repetition workout (flexible nonlinear) to perform on a given day resulted in greater increases in strength on the leg press. Affect could be a potential mechanism to explain the results of this study. By giving participants the autonomy to select the repetition scheme they would perform that day, the participants may have experienced a more positive affective response during their workouts. Through some neurophysiological mechanism, this may have allowed the participant to lift more weight.

  3. If affect is more positive, a lifter may put in more effort into the given exercise. This may enhance the mind-muscle connection or encourage the lifter to try harder; and thus, push them closer to muscular failure. A study by Schoenfeld et al. (2018) showed that when participants focused on establishing a mind-muscle connection with the muscles contracting, they experienced greater increases in strength and hypertrophy of the biceps than the participants who just focused on lifting the weight. Interestingly, the participants experienced similar growth in their quadriceps but the group who focused on just lifting the weight had greater increases in strength.

    The participants in this study (Schoenfeld et al., 2018) only performed 4 sets of 8-12 repetitions of the barbell biceps curl and machine knee extension 3 times a week for 8 weeks. Considering the participants were all male and relatively untrained (not having engaged in regimented resistance training for the past year) they may have had an easier time establishing a mind-muscle connection with their biceps than their quads. An interpretation of these results could be that the participants experienced greater pleasure when successfully establishing a mind-muscle connection with the biceps compared to when they struggled to find the mind-muscle connection with their quads.

  4. We know that major physiological adaptations can occur from the placebo effect (Crum & Langer, 2007). Perceptions and beliefs truly form our reality. To go on a little rant to support this statement, there is evidence to suggest that perceived health better predicts mortality than objective health markers (Kaplan & Camacho, 1983); increases in perceived levels of physical activity can confer physiological adaptations despite there being no actual changes in physical activity [1] (Crum & Langer, 2007); blood glucose levels in diabetics change based on how much time a diabetic has perceived to pass versus how much time has actually passed (Park, Pagnini, Reece, Phillips, & Langer, 2016); and, when perceived carbohydrate ingestion is similar, there are similar increases in performance despite there being differences in the actual amount of carbohydrates consumed (Mears et al., 2018). This list could keep going on and on.

    What readers of this blog will probably find most interesting is the effects of placebo anabolic-androgenic steroids on strength. Maganaris, Collins, and Sharp (2000) gave nationally ranked powerlifters what they described as “new, fast acting oral AS (anabolic-androgenic steroids).” At baseline, the researchers performed a 1RM test on two separate occasions to determine the best 1RM for each participant on each of the big three lifts. Then the participants performed the first experimental session where they were given two tablets of saccharin that they were led to believe were steroids. After this, one group performed the same procedure (given placebo steroids and performed a 1RM for squat, bench, and deadlift) while the second group was told that the oral steroid given to them was actually a placebo. This study showed all participants to increase their 1RM by anywhere between 2.5 to 12.5 kg for each lift when they thought they were receiving steroids. The group who thought they were still receiving steroids maintained this increase in load during the second experimental session while the group who was told that they were receiving placebo steroids saw a change of anywhere between -2.5 to +7.5 kg on their lifts. This study shows that the expectancy effect of ingesting anabolic steroids can significantly improve 1RM strength. It is possible that the participants felt better when they thought they were consuming steroids and were able to lift more weight. 

  5. To explain this last point, I have to go on a little tangent about the results of some studies dealing with stress before tying it back to affect. We know that stress has a negative impact on a lifter’s ability to increase strength and recover from training. Bartholomew, Stults-Kolehmainen, Elrod, and Todd (2008) investigated the effects of recent negative life events (stress) on changes in strength and hypertrophy over the course of a 12-week periodized resistance training regimen. They provided evidence to suggest that individuals with lower amounts of recent negative life events experience greater increases in strength from weightlifting. However, there appears to be no differences in hypertrophy [2].

    A major limitation of this study is that the participants were encouraged to engage in a third day of resistance exercise each week, but did not have to report if they completed it or not (so the authors could not provide rates of adherence). It is possible that the participants with lower amounts of stress, were simply able to train more. Since volume is a major driver of increases in strength (Ralston, Kilgore, Wyatt, & Baker, 2017) and hypertrophy (Schoenfeld, Ogborn, & Krieger, 2016), the low stress lifters may have performed more volume via training more frequently or adhering more to their program.

    However, there is more evidence to suggest that stress may be cock-blocking your gains. The same researchers who found stress to have a negative impact on strength went on to discover that higher levels of stress decreased the ability of muscles to recover from resistance exercise (Stults-Kolehmainen & Bartholomew, 2012). In this study, the participants performed a maximal isometric force test on a leg press, waited an hour, and then repeated the procedure. They also performed several other exercises/tests. It was found that lifters in the high stress group saw a greater decrease in performance when repeating this maximal isometric force test than lifters in the low stress group. Some may argue that this is simply because if you’re less stressed, you would probably have more energy and perform the maximal isometric force test with a greater intensity. However, it was found that participants in both groups had similar amounts of perceived energy and fatigue after performing the first round of tests and that stress was unrelated to absolute workload and heart rate during the tests. Therefore, this study suggests that perceived levels of stress attenuate a lifters ability to recover from training.

    I would like to point out that this is simply a correlational relationship and that there could be a third casual variable. The researchers realized this and went on to find out that lifters who are more stressed have a less positive affective responses to an acute bout of resistance exercise (Stults-Kolehmainen et al., 2016). Now it could very well be that more stressed individuals simply exhibit less positive affect as a result of being stressed. While this may very well be the case, the study still shows that high levels of perceived stress blunts the affective responses from exercise.

    Affect could be one of the mediating factors between the increases in strength and recovery seen in low stress individuals (Bartholomew et al., 2008; Stults-Kolehmainen & Bartholomew, 2012). The low stress lifters in both studies may have had a more positive affective response from resistance exercise which led to superior increases in strength and recoverable capabilities.

Chill out! Don’t let stress cock-block your gainz!

Potential Mechanisms

Before ending this article, I think it’s important for readers to understand that the whole body is connected through our lovely nervous system. The affective responses from exercise are mediated mainly by our limbic system (Burt, 1993). Researchers in neuroscience tend to focus on specific structures (e.g. amygdala, dorsolateral prefrontal cortex, insula) but all of the structures in the limbic system seem to play a role. The limbic system contains the hypothalamus which regulates many of the functions of the autonomic nervous system and plays a significant role in the endocrine system. Having a positive affective response from exercise could potentially allow the body to provide more fuel for the workout or release more anabolic hormones. Although current evidence suggests that acute increases in anabolic hormones doesn’t play a significant role in hypertrophy (Schroeder, Villanueva, West, & Phillips, 2013), the concept of increasing them through feeling good is intriguing. Additionally, the limbic system contains, or has direct connections, with many of the structures involved in motor control which may help with motor unit recruitment, synchronization, and firing rate (Burt, 1993). This will allow us to lift more weight in the gym.

I know the notion of feeling better during a workout leading to greater gains is dubious. However, I do think there is some evidence drawing a connection between affect and strength. If feeling better allows us to lift more weight for more repetitions, this will increase the volume of our workouts which should lead to greater increases in muscular size. Therefore, experiencing a more positive affective response during resistance exercise may lead to greater hypertrophy.

Again, I simply provided metatheoretical support for this hypothesis. I did so because I think it is important for people to realize that adaptations from training are complex and differ from person to person.


The main purpose of this article is for personal trainers to place a greater emphasis on how their clients feel during their workouts. Affect plays a major role in our decisions and has been shown to provide a strong influence over many health behaviors (Williams, Rhodes, & Conner, 2018). At the very least, having your clients experience pleasure and enjoyment from their training should lead to greater adherence to their training program.

Attention all personal trainers! Most of your client’s workouts should be centered around pleasure and enjoyment


Bartholomew, J. B., Stults-Kolehmainen, M. A., Elrod, C. C., & Todd, J. S. (2008). Strength gains after resistance training: the effect of stressful, negative life  events. Journal of Strength and Conditioning Research, 22(4), 1215–1221.

Benites, M. L., Alves, R. C., Ferreira, S. S., Follador, L., & da Silva, S. G. (2016). Are rate of perceived exertion and feelings of pleasure/displeasure modified in elderly women undergoing 8 week of strength training of prescribe intensity? Journal of Physical Therapy Science, 28(2), 407–411.

Bleich, S., Cutler, D., Murray, C., & Adams, A. (2008). Why Is The Developed World Obese? 273-295. doi:10.3386/w12954

Brand, R., & Ekkekakis, P. (2017). Affective–Reflective Theory of physical inactivity and exercise. German Journal of Exercise and Sport Research, (6).

Burt, A. M. (1993). Textbook of neuroanatomy. Philadelphia: W.B. Saunders.

Crum, A. J., & Langer, E. J. (2007). Mind-set matters: exercise and the placebo effect. Psychological Science, 18(2), 165–171.

Dombrowski, S. U., Knittle, K., Avenell, A., Araujo-Soares, V., & Sniehotta, F. F. (2014). Long term maintenance of weight loss with non-surgical interventions in obese adults: Systematic review and meta-analyses of randomised controlled trials. BMJ,348(G2646). doi:10.1136/bmj.g2646

Ekkekakis, P., Parfitt, G., & Petruzzello, S. J. (2011). The pleasure and displeasure people feel when they exercise at different intensities. Sports Medicine, 41(8), 641–671.

Ekkekakis, P., & Petruzzello, S. J. (2000). Analysis of the affect measurement conundrum in exercise psychology: I. Fundamental issues. Psychology of Sport and Exercise, 1(2), 71–88.

Fisher, J., & Steele, J. (2014). Questioning the Resistance/Aerobic Training Dichotomy: A Commentary on Physiological Adaptations Determined by Effort Rather than Exercise Modality. Journal of Human Kinetics,44(1), 137-142. doi:10.2478/hukin-2014-0119

Halperin, I., Chapman, D. W., Martin, D. T., Lewthwaite, R., & Wulf, G. (2017). Choices enhance punching performance of competitive kickboxers. Psychological Research, 81(5), 1051–1058.

Hamlyn-Williams, C. C., Freeman, P., & Parfitt, G. (2014). Acute affective responses to prescribed and self-selected exercise sessions in adolescent girls: an observational study. BMC Sports Science, Medicine & Rehabilitation, 6, 35.

Hardy, C. J., & Rejeski, W. J. (1989). Not what, but how one feels: the measurement of affect during exercise. Journal of Sport and Exercise Psychology, 11(3), 304–317.

Hassan, E. (2006). Recall Bias can be a Threat to Retrospective and Prospective Research Designs. Internet Journal of Epidemiology (Vol. 3).

Juvancic-Heltzel, J. A., Glickman, E. L., & Barkley, J. E. (2013). The effect of variety on physical activity: a cross-sectional study. Journal of Strength and Conditioning Research, 27(1), 244–251.

Kahneman, D., Diener, E., Schwarz, N., & Foundation., R. S. (2003). Well-being : the foundations of hedonic psychology. New York : Russell Sage Foundation,.

Kaplan, G. A., & Camacho, T. (1983). Perceived health and mortality: a nine-year follow-up of the human population laboratory cohort. American Journal of Epidemiology, 117(3), 292–304.

Maganaris, C. N., Collins, D., & Sharp, M. (2000). Expectancy Effects and Strength Training: Do Steroids Make a Difference? The Sport Psychologist, 14(3), 272–278.

McNamara, J. M., & Stearne, D. J. (2010). Flexible nonlinear periodization in a beginner college weight training class. Journal of Strength and Conditioning Research, 24(1), 17–22.

Mears, S. A., Dickinson, K., Bergin-Taylor, K., Dee, R., Kay, J., & James, L. J. (2018). Perception of Breakfast Ingestion Enhances High-Intensity Cycling Performance. International Journal of Sports Physiology and Performance, 13(4), 504–509.

Park, C., Pagnini, F., Reece, A., Phillips, D., & Langer, E. (2016). Blood sugar level follows perceived time rather than actual time in people with type 2 diabetes. Proceedings of the National Academy of Sciences of the United States of America, 113(29), 8168–8170.

Piercy, K. L., Troiano, R. P., Ballard, R. M., Carlson, S. A., Fulton, J. E., Galuska, D. A., … Olson, R. D. (2018). The physical activity guidelines for americans. JAMA, 320(19), 2020–2028.

Ralston, G. W., Kilgore, L., Wyatt, F. B., & Baker, J. S. (2017). The Effect of Weekly Set Volume on Strength Gain: A Meta-Analysis. Sports Medicine (Auckland, N.Z.), 47(12), 2585–2601.

Rhodes, R. E., & Kates, A. (2015). Can the affective response to exercise predict future motives and physical activity behavior? A systematic review of published evidence. Annals of Behavioral Medicine : A Publication of the Society of Behavioral Medicine, 49(5), 715–731. doi:10.1007/s12160-015-9704-5

Rose, E. A., & Parfitt, G. (2007). A quantitative analysis and qualitative explanation of the individual differences in affective responses to prescribed and self-selected exercise intensities. Journal of Sport and Exercise Psychology, 29(3), 281–309.

Sanli, E. A., Patterson, J. T., Bray, S. R., & Lee, T. D. (2012). Understanding Self-Controlled Motor Learning Protocols through the Self-Determination Theory. Frontiers in Psychology, 3, 611.

Schoenfeld, B. J., Ogborn, D., & Krieger, J. W. (2016). Dose-response relationship between weekly resistance training volume and increases in muscle mass: A systematic review and meta-analysis. Journal of Sports Sciences, 35(11), 1–10.

Schoenfeld, B. J., Vigotsky, A., Contreras, B., Golden, S., Alto, A., Larson, R., … Paoli, A. (2018). Differential effects of attentional focus strategies during long-term resistance training. European Journal of Sport Science, 1–8.

Schroeder, E. T., Villanueva, M., West, D. D. W., & Phillips, S. M. (2013). Are acute post-resistance exercise increases in testosterone, growth hormone, and IGF-1 necessary to stimulate skeletal muscle anabolism and hypertrophy? Medicine and Science in Sports and Exercise, 45(11), 2044–2051.

Stults-Kolehmainen, M. A., & Bartholomew, J. B. (2012). Psychological stress impairs short-term muscular recovery from resistance exercise. Medicine and Science in Sports and Exercise, 44(11), 2220–2227.

Stults-Kolehmainen, M. A., Lu, T., Ciccolo, J. T., Bartholomew, J. B., Brotnow, L., & Sinha, R. (2016). Higher chronic psychological stress is associated with blunted affective responses to strenuous resistance exercise: RPE, pleasure, pain. Psychology of Sport & Exercise, 22, 27–36.

Williams, D. M., Dunsiger, S., Ciccolo, J. T., Lewis, B. A., Albrecht, A. E., & Marcus, B. H. (2008). Acute affective response to a moderate-intensity exercise stimulus predicts physical activity participation 6 and 12 months later. Psychology of Sport and Exercise, 9(3), 231–245.

Williams, D. M., Dunsiger, S., Jennings, E. G., & Marcus, B. H. (2012). Does affective valence during and immediately following a 10-min walk predict concurrent and future physical activity? Annals of Behavioral Medicine : A Publication of the Society of Behavioral Medicine, 44(1), 43–51.

Williams, D. M., Rhodes, R. E., & Conner, M. T. (2018). Affective determinants of health behavior. New York: Oxford University Press.


[1] The participants in this study did not use accelerometers so there is actually no way of knowing if physical activity increased or not. However, since the participants reported not changing the amount of perceived activity outside of work, it is likely that their levels of physical activity remained fairly constant.

[2] It should be noted that the researchers did not use the best measurement of muscle hypertrophy. It is possible that the low stress group did see more growth but it wasn’t detected.