The effect of peer influence on exercise intensity and enjoyment during outdoor running in collegiate distance runners.

Carnes, Andrew J. ; Barkley, Jacob E.

While it is common for competitive athletes to train with teammates or training partners and exercising with a partner is a widely recommended method to increase exercise intensity and motivation (Kravitz, 2011), experimental research on the potential effects of exercising with others is limited. A number of studies on various populations (Corbett, Barwood, Ouzounogluo, Thelwell, & Dicks, 2012; Grindrod, Paton, Knez, & O'Brien, 2006; Plante et al., 2010; Rhea, Landers, Alvar, & Arent, 2003; Rittenhouse, Salvy, & Barkley, 2011; Salvy et ah, 2009; Williams, Nida, Baca, & Latane, 1989; Wilmore, 1968) suggest a positive effect of the presence of others on physical activity behavior, which may be explained by the social facilitation and self presentation theories of Zajonc (1965) and Bond (1982). These theories respectively propose that physical performance is enhanced in the presence of others as a means to "look good" or project an image of competence. In athletes, the impact of the presence of a peer on exercise behavior is equivocal and focuses primarily on maximal performance in a competitive setting (Corbett et al., 2012; Rhea et al., 2003; Williams et al., 1989; Wilmore, 1968). Although competitive performance is the primary concern of athletes, they perform a substantial amount of training at submaximal intensity, yet the effect of a peer on submaximal exercise behavior in athletes has been largely ignored.

Competitive distance runners are a suitable population in which to observe the effect of the presence of peers on athletes' submaximal training, as they frequently perform training runs with other runners (Kolata, 2009) and train at variable intensities in a given week. Current training philosophy (Daniels, 2005; Galloway, 2002; Martin & Coe, 1999; Noakes, 2004) supports a work--recovery model characterized by high intensity workout days followed by light to moderate intensity "recovery" or "easy" days. Training sessions on such "recovery" days are typically unstructured and allow runners to voluntarily select a submaximal level of exertion (Daniels, 2005; Galloway, 2002; Martin & Coe, 1999; Noakes, 2004).

Although runners and other athletes often train at submaximal intensity, we are presently aware of only one preliminary study (Carnes & Barkley, 2012), performed by our research group, that empirically investigated how training in the presence of teammates or partners affects athletes' submaximal training behavior. The study revealed no effect of peer influence on running intensity or enjoyment (i.e., liking). However, this study had a significant limitation in that all exercise was completed using treadmills. When running on adjacent treadmills, as was the case in this previous study, runners remained next to each other even when running different speeds, such that there was no need to "keep up" with a partner or group. Furthermore, the laboratory setting was anecdotally perceived as dull, with several participants commenting about being "bored." It is possible that any change in exercise liking caused by the presence of a peer was obscured or negated by negative feelings about the dullness and boredom of the laboratory environment. This was unsurprising as the runners in this previous study indicated that they trained daily outdoors, where running surfaces and surroundings change throughout the course of the run--which was not the case in the laboratory environment.

To our knowledge, prior to our preliminary study on runners (Carnes & Barkley, 2012), the impact of social interaction on this type of "free choice" exercise format has only been assessed in non-athlete adults (Grindrod et al., 2006; Plante et al., 2010) and children (Rittenhouse et al., 2011; Salvy et al., 2009), in whom the presence of others enhanced exercise behavior and/or liking. If a similar effect occurs in runners who train with others, this could have several possibly divergent implications: greater intensity during these types of sessions could cumulatively result in enhanced fitness and performance, while too great an increase in exercise intensity on intended light training days could prohibit recovery and lead to overtraining. In contrast, greater liking of training could help prevent mental fatigue or "burnout" in the course of an arduous season (Halson & Jeukendrup, 2004; Smith, Gustafsson, & Hassmen, 2010). It is therefore warranted to elucidate the behavioral and psychological effects of training with teammates and/or partners during unstructured exercise.

In the current study, we aimed to observe competitive male collegiate distance runners during nonspecific, voluntarily-paced training runs that coincided with their normal outdoor practice sessions, providing greater ecological validity than our previous study that used a laboratory setting and treadmills. The purpose of this investigation was to empirically examine how running with a single teammate or with a pair of teammates, relative to running alone, would affect exercise intensity and liking during an outdoor, self-paced training session in National Collegiate Athletic Association (NCAA) Division One male distance runners. We hypothesized that relative to running alone, the presence of one or two additional teammates would increase running speed and liking during an outdoor, submaximal, voluntarily-paced run.

Methods

Participants

Twelve NCAA Division One male distance runners (20.5 [+ or -] 1.98 years old) participated in the current study. Participants were current members of the university men's NCAA cross country team, or recently graduated ([less than or equal to] 2 years post graduation) team members who continued to train with the team. All participants were healthy with no contraindications to physical activity and reported a regular training volume of [greater than or equal to] 60 miles run x [wk.sup.-1]. Participant characteristics are presented in Table 1. Prior to participation, all participants provided written informed consent. All study methods were approved by the university Institutional Review Board.

Materials and Procedures

Each participant completed a baseline laboratory session and subsequently completed three running trials under three different social conditions (alone, with a peer, in a group of three total) in a randomized order. Each trial was performed outdoors on a measured asphalt foot and bicycle path that was closed to motor vehicles. Participants reported to each experimental session in place of their normal team practice session, on days when they were not assigned a structured workout or race. Research personnel collaborated with the head coach of the university cross country team to ensure that the present study did not interfere with the runners' competitive season, and that their runs on trial days were meant to be unstructured and voluntarily paced. These considerations were followed in order to replicate the participants' normal training as closely as possible. Each running trial consisted of a self-paced 6.4 kilometer run, and all trials were completed on the same measured portion of the trail. Participants were instructed to run to the end of the path (3.2 km from the starting point), turn around, and run back to the starting point (6.4 km total). The distance of the experimental trials was selected to replicate the participants' normal training, as both participants and the team's coach stated that a common "recovery day" run of approximately 4 miles (~6.4 km) was typical. This distance also matched a section of the path that was flat, well marked, and free of any road crossings. A researcher was stationed at the end of the path to ensure participants' safety and that each participant reached the turnaround point. The primary dependent variables in each trial were average running speed, enjoyment (i.e., liking) of the run, and ratings of perceived exertion (RPE) during the run. Experimental trials were conducted as close to the same time of day as possible ([+ or -] 2 hours) for each participant and occurred between 1:00 PM and 5:00 PM. Ambient temperature, relative humidity, and wind speed were recorded at the start of each session. All experimental sessions were completed in temperatures between 5[degrees]C and 15[degrees]C, with wind speed below 7 m x [s.sup.-1] and no precipitation. Participants were not permitted to wear personal music players or electronic timing or monitoring devices during the trial.

Baseline session. For the initial session, participants reported to the laboratory alone. Body mass was assessed to the nearest 0.2 kg and height to the nearest 1.0 mm using a balance beam scale (Health O Meter, Alsip, IL) and calibrated digital stadiometer (Charder Medical, Da Li City, Taiwan, China) respectively. Participants then completed a 10 minute warm-up run on a treadmill (Quinton MedTrack CR60, Bothell, WA) at a self selected pace in a climate neutral environment (19-21[degrees]C, ~40% relative humidity). After warming up, participants maintained their speed and the grade of the treadmill was increased by 2.5% every two minutes until volitional exhaustion (Costill & Fox, 1969). VO,, heart rate, and respiratory exchange ratio (RER) were monitored throughout the test. Heart rate was monitored using a downloadable telemetry monitor (RS800, Polar, Kempele, Finland). Expired air was collected and analyzed to determine peak oxygen consumption (VO, peak) using indirect calorimetry (True One 2400, ParvoMedics, Salt Lake City, UT). Undifferentiated, whole-body RPE was obtained in the last 15 seconds of each stage using the validated Borg 6-20 RPE scale (Borg, 1982). A large RPE scale was held in front of the participant, who could point at the number matching his perceived exertion. VO, peak was recorded as the peak VO, in ml-kg'-min-1 achieved during the progressive treadmill test.

Alone condition. The participant reported to the starting point alone. The following instructions were given: "Today you are going to complete a four mile run on the running path by yourself. You will run two miles to the end point of the path, turn around, and return to the starting point. This is not a test to see how fast you can go; treat this as your normal unstructured training run on any day without a structured 'workout'. There is no assigned pace or intensity--you are free to run at any pace you choose and you may change your pace at any time. Do not run with anyone you encounter on the path. When you return, we will ask you some questions about your run. Do you have any questions?" Elapsed time of the run was recorded in minutes and seconds. Average speed was calculated in km x [hr.sup.-1] by dividing the distance (6.4 km) by the elapsed time in hours (i.e., 30 minutes = 0.50 hours). Liking of each exercise session was assessed at the conclusion of the run with a visual analog scale (VAS), consisting of a continuous 100 millimeter line anchored by "do not like it at all" on the left and "like it very much" on the right. The participant was shown the scale and instructed to make a mark on the line to indicate his level of enjoyment. The position of the mark was measured in millimeters from the left anchor of the line, with a higher millimeter measurement indicating greater liking. "Liking" or "hedonics" is an affective rating of a behavior that, when assessed in this manner, directly correlates with physical activity participation (Craig, Goldberg, & Dietz, 1996; DiLorenzo, Stucky-Ropp, Vander Wal, & Gotham, 1998; Motl et al., 2001; Roemmich et ah, 2008). RPE (Borg, 1982) was also obtained at the conclusion of the run. The participant was shown the RPE scale and asked to report his average exertion throughout the course of the run.

Pair and group conditions. Two members (peer condition) or three members (group condition) of the university men's cross country team simultaneously completed the identical exercise trial described in the alone condition. Prior to each pair and group trial, all participants were asked privately about their relationship with any running partner in their pair or group and universally identified each partner as a friend and teammate. The same instructions were given as in the alone condition, but included a statement regarding the participant: "Today you will run together, and you may talk to one another if you wish. However, this is not a race or competition. Do not run with anyone else you encounter on the path." Measures were identical to the alone condition. Each participant rated his liking on the visual analog scale and reported his RPE in a private area separate from any other participants.

Statistical Analyses

All statistical analyses were conducted using SPSS for Windows (version 17.0, SPSS Inc, Evanston, IL) with an a-priori a level of [less than or equal to] 0.05. Means and measures of variability (standard deviation is reported in the text and all tables, standard error is reported in the figures) were calculated for all physical characteristics (height, body mass, age, V[O.sub.2] peak) and the primary dependent variables (average speed, liking of the activity, and RPE) for each social condition (alone, pair, group). Because all individuals in the study were participants, there was interdependence within each pair and group of participants who completed these peer conditions together. Therefore, mixed-effects regression models were utilized to examine all dependent variables over the three social conditions. Mixed models assume that the data within participants are dependent among the observations and can therefore be utilized to analyze data such as these where interdependence must be accounted for (Gibbons & Hedeker, 1994; Hedeker & Gibbons, 1994). The social conditions and groups were dummy-coded as either 0 (alone), 1 (pair), or 2 (group of three). Separate models were performed for each of the dependent variables (average speed, liking, perceived exertion). All regression analyses utilized the following model:

Dependent variable = [alpha] + [[beta].sub.1] (social condition)

Post-hoc paired t-tests were performed between social conditions for any dependent variable which had a main effect of social condition.

Results

Elapsed time (minutes), average speed (km x [hr.sup.1]), liking of the activity (mm), and ratings of perceived exertion (RPE) across social conditions (alone, pair, group) are presented in Table 2. Mixed model regression analysis revealed a significant main effect of condition (alone, peer, group) for average speed, F(2,33) = 5.75, p = .008, and liking, F(2,33) = 4.75, p = .016. Participants ran faster in the alone condition (M = 14.61, SD = 1.35) than in the peer (M = 13.76, SD = 1.26) or group (M = 13.68, SD = 1.81) conditions. Conversely, participants enjoyed running in a group (M = 78.41, SD = 8.86) more than running alone (M = 63.00, SD = 14.25), t(22) = 3.147, p = .005. There was a trend toward greater liking, t(22) = 1.83, p = .08, in the group condition than in the peer condition (M = 70.33, SD = 12.47 cm), but no significant difference in liking between the alone and peer conditions 1(22) = 1.31, p = .202. Average speed and liking across social conditions are presented in Figure 1 and Figure 2, respectively. There was no main effect of condition on RPE (p = .53).

[FIGURE 1 OMITTED]

[FIGURE 2 OMITTED]

Discussion

To our knowledge, this was the first study to empirically assess the effect of the presence of a single and multiple teammates, versus running alone, on the intensity and liking of outdoor running in competitive male distance runners. Participants in the present study ran significantly slower in pairs and in a group of three teammates total relative to running alone, but reported greater liking when running in a group. This conflicted with our hypothesis that exercising together with one or two teammates would result in greater exercise intensity, but supported our hypothesis that the presence of a teammate or teammates would result in greater liking of the exercise session. Our hypotheses were based on previous research in athlete (Corbett et al., 2012; Rhea et al., 2003; Williams et al., 1989; Wilmore, 1968) and non-athlete adults (Grindrod et al., 2006; Plante et al., 2010) and children (Rittenhouse et al., 2011; Salvy et al., 2009) which showed increased performance and/or physical activity behavior in the presence of others, as well as studies on children showing that the presence of peers increased the liking of physical activity (Craig et al., 1996; DiLorenzo et al., 1998; Motl et al., 2001; Roemmich et al., 2008).

In athletes, studies on weightlifters (Rhea et al., 2003), swimmers (Williams et al., 1989), and cyclists (Corbett et al., 2012; Wilmore, 1968) suggest that the presence of an audience or competition with other athletes can improve performance, but a conflicting study on runners (Bath et al., 2011) did not show the presence of another runner to affect 5k running performance. Our study also focuses on competitive athletes, but relates more closely to studies on adult non-athletes and children which do not involve competition and instead consider how the presence of others affects submaximal exercise. This question has not been adequately addressed in the previous literature involving competitive athletes, but is an important consideration as athletes spend substantial time training at submaximal intensity. In non-athlete adults, an unfamiliar single peer or a group of peers increased exercise intensity during walking (Grindrod et al., 2006) and cycling (Plante et al., 2010) exercise. Likewise, in studies on children the presence of a peer increased the amount, intensity, and liking of physical activity, as well as the motivation to be physically active, in a playground environment (Rittenhouse et al., 2011) and during cycling (Salvy et al., 2009) exercise. The present study is the first to observe competitive athletes during a training session of light to moderate intensity in order to examine how the presence of a single teammate or two other teammates would affect their voluntary exercise intensity and their liking of that session.

To our knowledge, it is also the first study to examine the effect of the presence of a peer or peers on exercise behavior in athletes or non-athletes that has reported that the presence of a peer(s) decreased exercise intensity relative to an alone condition.

While participants ran slower in the pair or group of three teammates conditions, they reported greater liking of running in a group than running alone. Although we hypothesized that social facilitation effects would encourage a greater exercise intensity in the presence of teammates, several participants stated that during the alone condition "I just wanted to get it done" when asked for any comments regarding each trial--suggesting a negative affect in this condition which may explain the faster speed when running alone. Furthermore, all participants mutually indicated being both teammates and friends with each person in their pair and group trials. Since we observed these participants during a training session that was not meant to be competitive or evaluative and all participants were friends with each other, the desire to demonstrate competence--that is, an individual's need for "self presentation" (Bond, 1982)--may have been lessened relative to running with someone unfamiliar. In studies on non-athlete adults that showed an increase in physical activity in the presence of others (Grindrod et al., 2006; Plante et al., 2010), subjects were not familiar with the other exercisers. In the current study, participants running with their teammates may have likened the training session to an enjoyable activity, possibly causing them to slow down and not rush to complete the session. Conversely, participants may have run faster when they were alone because this condition was less enjoyable and they wished to finish it as quickly as possible. In addition, Latane's "social loafing" theory (Karau & Williams, 1995) adds another possible explanation for slower running speed in the group condition. Although runners in the present study were not contributing to a competitive task requiring input from each individual to complete, such as a relay, the combination of participating in a group and a lack of pressure from the other group members being friends may have lessened participants' sense of personal accountability and thus promoted a reduced running effort.

While the results of the present study were unexpected, they still have potentially important implications. When predicting that training with others could lead to increased exercise intensity, we believed that such an effect could result in a cumulatively greater workload and ultimately enhance performance. However, in order to allow recovery and build aerobic endurance, prominent distance running coaches (Daniels, 2005; Galloway, 2002; Martin & Coe, 1999; Noakes, 2004) recommend that specific, high intensity training days be separated by unstructured, light intensity "easy days", usually performed at 50-75% of maximum heart rate (Daniels, 2005). For competitive runners who commonly have a tendency to inadequately vary their training intensity (Sallade & Koch, 1992), running with teammates/friends during sessions intended to be at light to moderate intensity could prevent overexertion in such sessions and thus prevent overtraining or injury. Furthermore, some research suggests that increasing exercise enjoyment (i.e., liking) may promote exercise adherence (Hagberg, Lindahl, Nyberg, & Hellenius, 2009) and prevent psychological burnout (Lemyre, Hall, & Roberts, 2007; Smith et al., 2010). Conversely, runners could reduce their fitness gains if the presence of teammates causes them to run too slowly during unstructured, submaximal running sessions.

The present study does have limitations that should be addressed in future empirical research on the effects of peer influence on exercise behavior in athletes and non-athletes. The study sample size was small (N = 12) due to a limited number of participants on the cross country team being observed. However, a post hoc power analysis showed that this sample size (N = 12) yielded adequate power ([greater than or equal to] 0.81) to reject the null hypothesis for average speed and liking. All participants were highly trained and competitive athletes accustomed to a high training volume and frequency. Therefore, observations in this study may not be applicable to general populations who exercise with a partner. Instead these results are to be generalized only to competitive athletes. Additionally, participants in each pair and group mutually indicated being friends with each other, which precludes the present study addressing the potential effect of exercising with an unfamiliar peer on exercise intensity and liking. The distance of the run was also held constant, which did not allow us to make inferences about the potential for the greater enjoyment observed in the group running condition to encourage the increased distance of a run. Runners were observed only for a single training session in each social condition, but varying fatigue from workouts or races may present another factor which could acutely impact the voluntary intensity of unstructured running sessions. Lastly, the present study observed only male subjects. Because of possible gender differences in the effect of social influence on physical activity (King, Blair, Bild, & Dishman, 1992), females may respond differently to an exercise partner or group. To address these concerns, future studies should include non-athlete adults and recreational athletes of both sexes, test the effect of an unfamiliar peer on exercise intensity and liking, and consider the possibility for social facilitation to affect not only exercise intensity and liking, but duration as well. Future research may also consider tracking runners longitudinally in different social environments to determine if regularly training in the presence of others has an effect on cumulative training volume or intensity over a period of weeks or months.

Conclusion

The purpose of this investigation study was to determine if, relative to an alone condition, exercising with a familiar peer or in a group of familiar peers affects average running speed and/or liking of the exercise bout during a self-paced outdoor run in a sample of competitive male collegiate distance runners. The presence of peers, relative to the alone condition, increased participants' reported level of liking of the exercise bout. Greater liking could potentially increase exercise behavior and/or reduce perceptions of burnout. However, contrary to the hypothesis, both peer conditions reduced average running speed in this group of athletes. A reduced submaximal running speed in the presence of teammates could potentially be beneficial if it prevents overexertion during light intensity sessions, but could also lessen aerobic development if submaximal runs are performed too slowly. As all participants were friends, more research is needed to determine if the presence of an unfamiliar peer will have a different effect on exercise behavior. Female participants and recreational exercisers may also have different responses to exercise with a peer.

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Andrew J. Carnes

Bellarmine University

Jacob E. Barkley

Kent State University

Address Correspondence to: Andrew J. Carnes Bellarmine University. 2001 Newburg Road, Louisville KY 40205. Email: acarnes@bellarmine.edu.

Table 1
Participant Characteristics

Age (yr)                                            20.5 [+ or -] 0.57

Body Mass (kg)                                      69.3 [+ or -] 2.14

Height (cm)                                        179.8 [+ or -] 1.85

V[O.sub.2] Max (ml x [kg.sup.-1] x [min.sup.-1])    73.3 [+ or -] 5.73

Values are reported as means [+ or -] SD, N = 12

Table 2
Elapsed Time, Average Speed, Liking, and RPE Across Social Conditions

                                  Alone                 Peer

Elapsed Time (min) *       26.4 [+ or -] 1.35    28.0 [+ or -] 1.26

Speed (km-[hr.sup.-1]) *   14.6 [+ or -] 1.35    13.7 [+ or -] 1.26

Perceived exertion         11.0 [+ or -] 1.50    10.0 [+ or -] 1.13

Liking (mm) *              63.0 [+ or -] 14.24   70.3 [+ or -] 3.59

                                 Group

Elapsed Time (min) *       28.3 [+ or -] 1.80

Speed (km-[hr.sup.-1]) *   13.6 [+ or -] 1.81

Perceived exertion         11.5 [+ or -] 2.19

Liking (mm) *              78.4 [+ or -] 8.85

Values are reported as means [+ or -] SD, N = 12. * Significant
difference between social conditions (p < 0.016).