Saturday, November 13, 2010

Group Dynamics and Individual Success

As important as personalized goals and attention are to individual success, it’s equally important to recognize the effect of group dynamics on individual success. A great many physical activities take place in groups and for many the group’s success is dependent on encouraging positive group dynamics. However, positive group dynamics can also have a positive effect on individual success. Understanding the effects can help maximize not only the group’s success but individuals’ success.

One form of group dynamics is team building. Carron, Hausenblas, & Eys (as cited in Gill & Williams, 2008, p. 261) defined team building as "team enhancement for both task and social purposes." This definition acknowledges the dual nature of team building: not just improved task performance, but also improved social connectedness. And as Carron, Colman, Wheeler, & Stevens (2002) discovered, both task and social cohesion are positively associated with performance. But how can team building help with individual success? A physical education class for seventh grade boys and girls with varying levels of interest and skill provides an excellent example. Students with less skill may feel intimidated by their more skilled peers. Smith and Smoll (1997) found that team building was an effective way of reducing performance anxiety as well as improving self-esteem. Therefore team building is a way in which students can be encouraged to participate and improve their skills.

Based on Yukelson’s (1997) advice, there are several strategies that can be used in team building. Having the students create a special name for their class and wear a colored wristband unique to their class can help to create a team identity. Assigning a more skilled student to work with a less skilled student and creating an environment where positive feedback is expected from and for all students can help foster peer helping and social support. Setting group goals as well as individual goals with the input of students on both topics can create a unity of purpose. And to maintain open and honest communication, students should be encouraged to share their concerns, ideas, and accomplishments with the group during a group share at the end of each class.

As touched on earlier, social support is an important component of group dynamics. Shumaker and Brownell (as cited in Gill & Williams, 2008, p. 251) define social support as "an exchange of resources between at least two individuals perceived by the provider or the recipient to be intended to enhance the well-being of the recipient." Social support can be seen, then, as a positive dynamic between two or more people. To examine how social support might impact individual performance, let’s look at an exercise program for older adults in good health at a senior center. One of the main reasons that older adults attend senior centers is for the social support (Krout, 1983). This social support can have a positive effect on the older adults’ well-being, but it can also help improve their physical activity performance. Duncan and McAuley (1993) found that social support improves self-efficacy which is a crucial part of performance.

Rosenfeld and Richman (as cited in Gill & Williams, 2008, p. 252) created a model of social support that includes three broad types of social support: tangible, informational, and emotional. All three types can be incorporated into the senior center’s exercise program. Tangible support can be provided as assistance with utilizing exercise equipment and with performing other physical activities. Informational support can be provided with positive feedback and advice from the instructor as well as fellow participants. Emotional support can be provided as part of a consultation with the instructor when setting and evaluating personalized goals for the individual participants as well as during group instruction when instructors and participants can provide encouragement.

Improving group dynamics through team building and social support can have a positive impact on individual success as well as group success. Team building can encourage participation by improving self-esteem and reducing performance anxiety. Social support can improve performance by increasing self-efficacy. Groups that take into account the effects of group dynamics on individuals can increase both performance and effectiveness.


Carron, A., Colman, M., Wheeler, J., & Stevens, D. (2002). Cohesion and performance in
     sport: A meta analysis. Journal of Sport & Exercise Psychology, 24(2), 168-188.

Gill, D. L., & Williams, L. (2008). Psychological dynamics of sport and exercise (3rd
     Ed.). Champaign, IL: Human Kinetics.

Krout, J. (1983). Correlates of senior center utilization. Research on Aging, 5(3), 339-352.

Smith, R. E. & Smoll, F. L. (1997). Coach-mediated team building in youth sports. Journal of
     Applied Sport Psychology, 9
(1), 114-132. doi:10.1080/10413209708415387

Yukelson, D. (1997). Principles of effective team building interventions in sport: A direct
     services approach at Penn State University. Journal of Applied Sport Psychology,
(1), 73-96. doi:10.1080/10413209708415385

Thursday, November 4, 2010

Promoting Physical Activity in Families

Family activities provide an opportunity for socializing in an age where families are increasingly disconnected by divergent daily schedules. Engaging in physical activities as a family can not only provide a way for families to spend more time together, but it can also help sustain parent-child communication (Thompson, Jago, Brockman, Cartwright, Page, et al., 2010) and assist each member of the family in developing healthy fitness habits. Many Parks & Recreation departments offer adequate facilities and programs, but the programs and classes focus primarily on individuals participating with their peers. The Families Together & Active program aims to provide physical activity instruction geared towards families participating together. The goals of the program are twofold: to improve participants’ performance and to foster positive attitudes toward physical activity.

Although family members may also opt to participate in activities on their own, having activities that families can participate in together offers important benefits. Primarily, it allows parents to serve as models of behavior for their children, both in valuing physical activity and in performing the actual tasks. Bryan (as cited in Gill & Williams, 2008, p. 216) found support for the popular adage “actions speak louder than words” in that individuals (and specifically children) are more likely to do what they see another person doing rather than what the person says to do. Horn and Horn (as cited in Gill & Williams, 2008, p. 218) found more specifically that parents’ attitudes and beliefs regarding physical activity as evidenced by their behaviors had a great influence on their children’s attitudes and behaviors. So parents participating in physical activities with their children can help the children develop positive attitudes towards physical activity. McCullagh and Weiss (as cited in Gill & Williams, 2008, p. 215-216) posited that watching someone else learn a task can help an individual learn the task as well. And watching someone who is perceived to be similar to oneself, such as a family member, can increase performance among individuals as well (Gould & Weiss, as cited in Gill & Williams, 2008, p. 216). Therefore watching their parents learn a task can increase a child’s performance as well as help them to learn the task.

The availability of a variety of physical activities for families to participate in together is also important. Each family member is likely to have their own opinion on what activities interest them. A wide variety increases the likelihood that families will find an activity that they can all agree on. Some of the classes to be offered for families to participate in together (based on instructor availability) include: karate, yoga, tennis, basketball, hiking, soccer, and swimming. The focus in these classes will mainly be on basic skills, but encouraging interaction among the participants will also be an important component. Participants will also be encouraged to practice their skills at home with a “homework assignment.” This “homework” may consist of breathing exercises or practicing movements/poses and should be completed with the help of a family member, who can provide feedback.

In addition to instructor-lead classes, families would have access to facilities for open use on certain days/times. This not only gives families time to practice what they are learning in instructor-lead classes, but it also encourages them to continue their physical activity in a non-structured way. This prepares them for continuing their fitness habits outside of a class setting which helps ensure long-term maintenance of physical activity and fitness.

Parents have a great influence on their children’s attitudes and behaviors when it comes to physical activity. By implementing a program that allows parents and children to participate together in physical activities, the positive effects of parental modeling can be maximized to increase performance and positive attitudes. Additionally, family participation can help to foster an environment at home where physical activity and other healthy habits are the norm.


Gill, D. L., & Williams, L. (2008). Psychological dynamics of sport and exercise
     (3rd Ed.). Champaign, IL: Human Kinetics.

Thompson, J. , Jago, R. , Brockman, R. , Cartwright, K. , Page, A. , et al. (2010).
     Physically active families de-bunking the myth? A qualitative study of family
     participation in physical activity. Child Care, Health & Development, 36(2), 265-

Sunday, October 24, 2010

It's Action Adventure Time!

Developing healthy habits can be difficult at any age. And unfortunately many children develop unhealthy habits that complicate the process of adopting a healthy lifestyle when they are older. A school environment offers an opportunity to introduce healthy habits to children and provide direction that will set up a foundation for maintaining those habits through their adult life. And as being overweight or obese is negatively related to academic achievement and school attendance (Datar & Sturm, 2006; Strong et al., 2005), it is in a school’s best interest to use their resources to advocate fitness among their students. In developing an after-school program for overweight children in middle school, I utilized several strategies that will help students adopt a healthy lifestyle.

The name of this after-school program is “Action Adventure Time!” which is an allusion to the popular animated tv show on Cartoon Network called “Adventure Time.” As a lack of physical activity has been linked by the US Department of Health and Human Services to a number of major health problems (as cited in Gill & Williams, 2008, p. 148), the main goals of the program will be to reduce risk for cardiovascular disease and diabetes and to promote health and well-being through physical activity. Most of the target population for this program are likely to be beginners when it comes to physical activity, so it’s important to start by disseminating information about the program and its benefits. Information about the program will be provided to parents and students in the form of fliers sent home with students, information meetings for both parents and students, and, if feasible, phone calls to parents. Presenting the information in a positive and welcoming manner can help ease some of the concerns of both parents and students and pique their interest in their program.

Once it starts, the program will continue with cognitive processes of behavior change which include increasing knowledge, becoming aware of risks, understanding benefits, and increasing opportunities to apply knowledge. These processes work well for people who are in either the precontemplative (do not intend to exercise within the next 6 months) stage or contemplative (intend to start exercising within the next 6 months) stage as defined by Marcus, Rossi, Selby, Niaura, & Abrams (as cited in Gill & Williams, 2008, p.155). Moving to the preparation stage where people are exercising, although not regularly (again defined by Marcus et al.) is the objective that must be reached first. An individualized plan with short-term, achievable goals for physical activity should be implemented for each child to boost their self-efficacy. The physical activity will start off slowly with basic stretching and aerobics in addition to sports-related activities. Frequent reinforcements in the form of praise, support from the other children in the program, and feedback on progress will be provided to all of the children. Additional support in the form of behavioral contracts, exercise cues, and positive self-talk may also be used to help students acquire exercise habits. As the students begin to progress, the amount of physical activity will gradually increase as will the intensity of the activities offered (i.e. running in place of walking).

As students move into the preparation stage, behavioral processes will be added to help them begin the transition to maintaining their exercise habits. Activities that can be performed at home will be added to student plans. Students will be encouraged to talk to each other outside of the program about their continued physical activity. Parents will be encouraged to reinforce good habits at home. Students will develop their own personal reward system to help themselves stay committed to their exercise habits. Relapse prevention will be discussed. This will help students move to the final stages described by Marcus et al.: action (exercising regularly for less than 6 months) and maintenance (exercising regularly for more than 6 months). The ultimate goal will be for students to participate in at least 60 minutes of physical activity each day which is the recommended amount for the most health benefits in the dimensions of skeletal health, aerobic fitness, and muscular strength and endurance (Strong et al., 2005). This total will include recess time and school-based physical education as well as the activities developed in the after-school program.

In conclusion, the “Action Adventure Time!” after-school program can assist overweight youth to develop healthy habits by helping them to add more physical activities to their daily lives. This will improve not only their current health and well-being, but it will form the groundwork for future goal-setting and achievement.


Datar, A., & Sturm, R. (2006). Childhood overweight and elementary school
     outcomes. International Journal of Obesity, 30(9), 1449-1460.

Gill, D. L., & Williams, L. (2008). Psychological dynamics of sport and exercise
     (3rd Ed.). Champaign, IL: Human Kinetics.

Strong, W. B., Malina, R. M., Blimkie, C. J. R., Daniels, S. R., Dishman, R. K.,
     Gutin, B., ... Trudeau, F. (2005). Evidence based physical activity for 
     school-age youth. The Journal of Pediatrics, 146, 732 – 737.

Friday, October 15, 2010

Motivating Positive Behaviors and Attitudes

Participation in a physical education class can be influenced by a number of factors. Some children are ready and eager to try every activity. And some children seem unwilling to try any. Understanding what motivates these behaviors can help physical education teachers to connect with the children they teach and encourage participation.

Let’s take the example of Kate and Robin who are both in the ninth grade. Kate is an eager participant and readily takes on challenges. She isn’t deterred by her failures and enjoys participating in the different activities. Robin doesn’t appear to enjoy physical education and avoids participating if possible, even though she is quite capable. When she does participate, she chooses either simple tasks or impossible challenges to ensure the easy success or assured failure. Although it is tempting to focus on only Robin’s needs in this scenario, it is important to not neglect Kate. It is the extremes of these two girls that illustrate the challenge that faces physical education teachers: what is the best way to address the differing needs of students?

We’ll start with an achievement motivation assessment profile of each student. Kate clearly shows that she is task-oriented. Task-oriented individuals are focused on learning and improving. For Kate, failures are not a problem because the point is not to win: the point is to work on getting better and have fun. Without the pressure of always succeeding, Kate enjoys physical education. Robin, on the other hand, is ego-oriented. Ego-oriented individuals are focused on performing better or equal to their peers. For Robin, failures are unacceptable risks because the point is to win or to always perform a task successfully. This means that the pressure is always on to succeed and consequently Robin is not able to enjoy athletic activities. Although ego-orientation can work under some circumstances, it’s not working for Robin because she doesn’t believe she can succeed if challenged. To have a more positive experience, Robin needs to become more task-oriented like Kate is. Not only would Robin be more successful, she would also have more fun.

The challenge now is how to encourage task-oriented behavior in both girls. The answer is by changing the motivational climate. Ames and Archer (1988, as cited in Gill & Williams, 2008) defined motivational climate as people’s perceptions of the goal structure and is a function of the group goals, underlying reward system, interactions among group members, and individual interpretation of the specific social structure. In simple terms: what goals and behaviors are rewarded? Rather than having winning or success be the behaviors primarily rewarded, the emphasis needs to be on learning and effort. Mastery climate is more likely to encourage self-referenced improvement and effort (Wang, Woon Chia, Chatzisarantis, & Lim, 2010). In creating an environment that rewards task-oriented behaviors, both girls will be encouraged: Kate to continue on her path and Robin to change her focus from comparing herself to others.

Part of implementing this change in climate is going to involve setting more personal goals for each girl. Kate may already be setting personal goals like improving her volleyball serve, but talking with her on an individual basis can help reinforce these goals and the goal-setting behavior. Robin will need a little more help setting goals for herself. And in the beginning the goals may need to be short-term goals that she can accomplish in a single practice session to boost her self-confidence. Then as she advances she can set more long term personal goals. Both students should be rewarded for their efforts with verbal praise or other rewards that the girls find motivating.

Although it may seem that Kate and Robin’s needs are at odds with each other, there is a solution that addresses both of their needs. By encouraging task-oriented behavior within a mastery climate, both girls will receive the encouragement that they need to be successful and enjoy physical education.


Gill, D. L., & Williams, L. (2008). Psychological dynamics of sport and exercise
     (3rd Ed.). Champaign, IL: Human Kinetics.

Wang, J., Woon Chia, L., Chatzisarantis, N., & Lim, C. (2010). Influence of
     perceived motivational climate on achievement goals in physical education: A
     structural equation mixture modeling analysis. Journal of Sport & Exercise
     Psychology, 32 (3), 324-338. Retrieved from SPORTDiscus with Full
     Text database.

Managing stress through exercise

Following a routine for exercise and physical fitness is often difficult. There are numerous factors that can affect one’s ability to adhere to the routine and once you stop, it can be difficult to get back into the routine. In my past life as a Marine, it was easy to maintain an exercise routine since routine was built into nearly every aspect of my daily life. In my current life as a father, full-time employee, and part-time student, maintaining a routine of any kind is nearly impossible. However, given the stress currently going on in my life an exercise routine can offer me numerous benefits both physically and mentally.

To implement a behavior plan for myself, I need to: clarify the problem, formulate goals for the consultation, design target behaviors, identify the maintaining conditions of the target behavior, design a treatment plan, implement the plan, and evaluate the success of the plan (Gill & Williams, 2008, p.101-102).

The main problem for me at the moment is overwhelming stress. The physical and mental fatigue of the stress makes it incredibly difficult to focus on the things that I need to accomplish. One of my target goals, then, is to decrease the negative effects of the stress by getting back into a daily running routine. It will take time to reach that goal, so the initial target behavior is to find at least 15 minutes every day to run. The ultimate target behavior will be to find at least 30-45 minutes a day to run, so as I am able to find more time I will increase my target behaviors.

To not only determine my maintaining conditions but also to facilitate continued adherence to the routine, I opted to do some self-monitoring as Polaha, Allen, & Studley  (2004, as cited in Gill & Williams, 2008) found it to be a simple and effective way of changing behavior. Over the past few weeks, when I have found time to go running I have felt the physical benefits almost immediately. I am able to calm my mind and focus only on running. The endorphins I felt after running gave me a respite from all of the tension and mental stress. There haven’t really been any punishments associated with running, with the possible exception of leaving less time to accomplish the other things that I need to accomplish. I often feel like there isn’t time to run because there is so much else that needs to be done.

Running does provide its own negative reinforcement as the physical and mental effects of stress are lessened after I run. However, I feel that some additional positive reinforcement would help me to get back into the routine. I decided to enlist the assistance of my friends as positive reinforcement. I will talk with at least one friend each day about how my routine is going and what I have accomplished. They’ll provide positive encouragement and praise to encourage me to keep up with the routine. I’m also going to incorporate some self-talk and progressive relaxation techniques into my day as ways of combating the thoughts that dissuade me from exercising.

I implemented this plan in the past week and so far the results have been satisfactory. I managed to go running for at least 15 minutes on three days and as much as 30 minutes on one of those days. I think in the coming weeks, I need to focus more on stress coping skills outside of exercise. Taking a break from the stressors in my life is beneficial, but I also need to incorporate more coping skills into my day to avoid falling right back into the overwhelming stress and tension that I took a break from.


Gill, D. L., & Williams, L. (2008). Psychological dynamics of sport and exercise
     (3rd Ed.). Champaign, IL: Human Kinetics.

Thursday, October 14, 2010

Improving Quality of Life Through Exercise

When implementing any exercise program, it is crucial to consider the individual needs of the participants. However, it is also important to be familiar with the particular needs of the population that you are serving. Many populations have specific issues and concerns that can impact the effectiveness of the program.  For breast cancer survivors, quality of life is one major concern and an exercise program geared for this population needs to address that issue.

First, let’s define quality of life. As defined in Gill and Williams (2008), quality of life (QoL) is “a broad, integrative construct, comprising the person’s perceived physical, social and psychological well-being” (p. 177). And Gill et al. (as cited in Gill & Williams, 2008) proposed a hierarchy of well-being that further delineated these three categories into: social well-being, physical well-being (including physical health symptoms, physical fitness, and physical functioning), cognitive well-being, emotional well-being, and spiritual well-being. This holistic approach to quality of life allows for the various personal definitions of quality of life among individuals and addresses the multifaceted aspects of quality of life.

An exercise program’s main purpose is to address physical quality of life issues, as research supports the notion that physical activity can improve quality of life (Gill & Williams, 2008). Breast cancer survivors have been weakened by illness and treatment. Exercise offers a road to recovery from the physical effects on their body. However, there is great variance among breast cancer survivors:  age, length of illness, severity of illness, and physical activity level prior to illness can all impact the exercise needs and abilities of the individual. Offering a variety of types of exercise allows not only for these individual differences but also provides a more comprehensive approach to physical rehabilitation. Offering enjoyable types of activities that are not normally associated with “exercise” such as dancing can help motivate participants who might be disinclined to participate in more traditional types of exercise.

The good news is that an exercise program can actually address more than just the physical aspects of quality of life. Milne, Guilfoyle, Gordon, Wallman, and Courneya (2007) found that participants in an exercise program often focused more on the social benefits of the exercise program. They saw the main benefit of the exercise program not as the physical benefits, but the social benefits of a shared experience with others who had experiences similar to theirs. Social support has been found to be an important predictor of successful recovery from breast cancer (Kroenke, Kubzansky, Schernhammer, Holmes, & Kawachi, 2006), so an exercise program that encourages socialization among participants can serve a dual purpose. One could even argue that this socialization can improve the emotional well-being of the participants by giving them opportunities to have discussions with other survivors in various stages of recovery. For example, a newly recovering participant may find comfort in talking with a survivor who has been in recovery for several years.

Additionally, Milne et al. (2007) found that exercise gave breast cancer survivors a sense of mastery over their own bodies. In both the effects of breast cancer and its treatment, women felt as if their own bodies were turned against them. Exercise allowed them a way of returning that control to themselves. Although this could be seen as an indicator of physical well-being (and it is), this can also be seen as a sign of cognitive well-being. The participants are returning to a way of thinking positively about their bodies and repairing their mind-body connection. It’s also important to recognize that women need to regain control over their lives as well as bodies. Andersen, Bowen, Morea, Stein, & Baker (2009) found that the long-term prognosis for breast cancer survivors improved if the survivors felt that they had more power over the decision making in their follow-up care. In an exercise program, then, it is not only important to assess individual needs but to allow the individual to have a say in what form that program takes.

In conclusion, an exercise program can improve quality of life for breast cancer survivors (as well as other populations) in a variety of different ways. Keeping these aspects in mind when creating the program can help to enhance the positive effects of the program and improve the chances of recovery for all of the participants.



Andersen, M., Bowen, D., Morea, J., Stein, K., & Baker, F. (2009). Involvement in decision-

     making and breast cancer survivor quality of life. Health Psychology, 28(1), 29-37.



Gill, D. L., & Williams, L. (2008). Psychological dynamics of sport and exercise (3rd

     Ed.). Champaign, IL: Human Kinetics.


Kroenke, C. , Kubzansky, L. , Schernhammer, E. , Holmes, M. , & Kawachi, I. (2006).

     Social networks, social support, and survival after breast cancer diagnosis. Journal of

     Clinical Oncology, 24(7), 1105-1111.


Milne, H., Guilfoyle, A., Gordon, S., Wallman, K., & Courneya, K. (2007). Personal accounts

      of exercise and quality of life from the perspective of breast cancer survivors. Quality of

     Life Research, 16(9), 1473-1481. doi:10.1007/s11136-007-9251-z.

Monday, October 4, 2010

Workplace Stress and Coping Through Exercise

Many people use exercise as a way of coping with stress and with good success. Creating a stress management plan that incorporates emotional control as well as exercise can ensure that even when a person is unable to get to the gym, they will have coping methods that they can use to deal with immediate stressors.
Long hours and high responsibility have created a lot of stress for a financial manager, but she finds that exercise relieves the stress. As her personal trainer, I can help her to incorporate additional coping methods that will increase the stress relief that she feels when exercising as well as help her deal with stressors when she is not exercising.
Emotional control is an important first step in stress management. As noted by Ziegler (as cited by Gill & Williams, 2008), emotions can affect a person physically and likewise physical symptoms can affect emotions which creates a negative thought-anxiety cycle. The two feed into and off of each other, increasing the negative effects of both. Breaking this cycle using cognitive skills or cognitive-behavioral skills is a way of taking this first step.
Focus is an important part of exercise as well as sports. Gill & Strom (1985) found that a narrow and external focus resulted in more repetitions of an endurance task and participants preferred that method to a narrow and internal focus. A narrow and external focus is another way of describing dissociation: that is, the person is focusing on a very specific thing that is outside of their bodies, such as a photograph or clock. In terms of stress management, this would manifest itself as putting aside all of the worries and stresses that an individual is feeling and focusing attention on the specific task at hand or on a specific external item as  the individual is exercising. This should result in not only better results when exercising, but also provides a respite from the worries and stresses the individual is feeling.
Cognitive-behavioral techniques are beneficial as they address both the cognitive and physical aspects of stress. In a way, the two work together as an antidote to the negative thought-anxiety cycle by creating a positive correlation between thoughts and physical reactions, with each feeding into and expanding on the other. The cognitive component may involve cognitive skills such as cognitive restructuring in which the individual identifies that a thought is negative, replaces the negative thought with a more positive and constructive one, and then reinforces this using self-talk. The physiological component may involve relaxation techniques such as progressive relaxation which is a method of relaxation that involves tensing a specific muscle group and then relaxing it, using breathing techniques as a cue (i.e. tense the muscle group, then slowly relax it as you breathe in and out deeply). The process is then repeated for various other muscle groups.
So how does this apply to the stressed financial manager? Using Ron Smith’s (as cited by Gill & Williams, 2008) model for cognitive-affective stress management, we start with an initial consultation with the financial manager to fully identify her situation and her specific needs. Following that, we can develop a stress management plan together and I can inform her of the ways in which this specific plan is going to assist her to ensure her buy-in. Next, we’ll start working on acquiring the necessary cognitive and cognitive-behavioral skills she needs to use. We’ll practice focusing on a specific external object while she exercises to help clear her mind and improve her endurance. We’ll practice cognitive restructuring by examining some of her negative thoughts and specific counter-points to those negative thoughts. We’ll practice progressive relaxation to help relieve the physical tension in her body any time she feels stressed. With the skill rehearsal, we’ll construct imaginary but plausible scenarios that she may encounter in the future and ways in which she can apply cognitive restructuring or progressive relaxation in these scenarios. Throughout this process, we’ll continue to evaluate the benefit of this model and alter it as needed.
Workplace stress can be especially daunting when an individual works long hours and has a great degree of responsibility. Exercise can help alleviate stress by offering both a distraction and an outlet. Cognitive skills can help an individual focus on the physical task and Cognitive-behavioral skills can also help an individual develop coping mechanisms that they can use in the workplace.


Gill, D.L., & Strom, E.H. (1985). The effect of attentional focus on performance of an endurance 
     task. International Journal of Sport Psychology, 16, 217-223.

Gill, D. L., & Williams, L. (2008). Psychological dynamics of sport and exercise (3rd
      Ed.). Champaign, IL: Human Kinetics.