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Despite the physical and mental health benefits, few adults meet US Department of Health and Human Services physical activity guidelines for exercise frequency, intensity, and duration. One strategy that may increase physical activity duration is exercising with an Internet partner (ie, someone who is virtually present, as in video chat). Internet partners help people overcome many barriers associated with face-to-face exercise groups (eg, time, coordinating schedules, social physique anxiety). Past research examining individual performance in groups suggests that an increase in effort occurs when performing a task conjunctively, ie, when a participant is (1) less capable than fellow group members, and (2) participants efforts are particularly indispensable for group success (ie, where the group’s potential productivity is equal to the productivity of its least capable member). This boost in effort is more commonly known as the Köhler effect, named after the German psychologist who first observed the effect. While encouragement between group members is common practice in face-to-face group exercise, the effect of encouragement between partners exercising conjunctively across the Internet is unknown.
To examine the impact of exercising alone, compared to exercising conjunctively with an Internet partner, both with and without encouragement, on exercise persistence (primary outcomes) and secondary psychosocial outcomes (self-efficacy, enjoyment, exercise intention).
Participants were recruited online and face-to-face from the campus of Michigan State University. With the assistance of the experimenter, participants (n=115) played an exercise video game in a laboratory, performing a series of five abdominal plank exercises where they were asked to hold the plank for as long as possible (Time 1). They were then randomized to a condition (Individual, Partner-without-encouragement, or Partner-with-encouragement), where they performed the exercises again (Time 2). The impact of condition on the primary outcome measures and secondary outcome measures were evaluated using a 2 (Gender) x 3 (Condition) ANOVA on change scores (Time 2-Time 1).
Those who exercised in online teams (n=80) exercised significantly longer (time=78.8s,
Exercising conjunctively with an Internet partner can boost one’s duration of exercise. However, encouragement from the stronger to the weaker member can mitigate these gains, especially if one perceives such comments being directed at someone other than themselves. To boost exercise duration, Internet-based physical activity interventions involving group interaction should make relative abilities of participants known and communication clear.
Despite the links between regular physical activity and positive health benefits [
Recent research has highlighted the influential role of social factors in physical activity behavior, including exercising with a partner [
The purpose of the current study was to test the efficacy of an Internet partner in increasing exercise duration. Specifically, we tested whether being the “weak link” on a team with an Internet partner could motivate one to exercise longer than when exercising alone. Further, we tested whether encouragement from the partner could motivate one to exercise longer still.
Basic behavioral research in social psychology suggests that the presence of a superior partner may motivate one to exercise longer than they would when exercising alone and further still if one is on a team with that partner and is the team’s “weak link” [
The study used a randomized trial in a 3 (condition: individual control, partner with- encouragement, partner-without-encouragement) x 2 (performance block: Block 1 & Block 2) factorial design. Eligible participants were students who had no physical injuries that would prevent or obstruct their performance during an isometric plank exercise.
The study was conducted in a laboratory on the campus of Michigan State University in the Departments of Kinesiology and Psychology and was approved by the Institutional Review Board. Most of the data for two of the conditions (ie, 26 participants in the individual condition and 47 in the partner-without-encouragement condition) were collected as part of a study [
The task for this study was an abdominal plank exercise. These are body-weight resistance exercises where participants suspend their own body weight using their abdominal muscles. These exercises are also isometric in nature, require very little coordination, and are highly effort-based. Each exercise targeted the abdominal muscles, but there were slight differences between each (eg, holding a push-up position on one’s forearms vs on each side; a detailed description of all exercises is provided elsewhere [
The exercises were performed as part of an exercise video game designed for the PlayStation 2 (PS2) gaming system as used in a previous study [
A detailed description of experimental procedures is provided elsewhere [
After arriving at the laboratory, participant consent was obtained and all were ensured of the confidentiality and voluntary nature of their participation. Participants then watched a brief instructional video from the PS2-Eye Toy: Kinetic software in which a virtual trainer demonstrated the five exercises. A baseline measure of self-efficacy was then taken using an online questionnaire completed in the laboratory. Participants were asked throughout the session if they understood all instructions and, if not, the experimenter addressed his/her questions. All participants then performed the first block of exercises, holding each of the five exercises for as long as they could and with 30s rest periods between each exercise. Immediately after each exercise, the participant announced his/her perceived exertion. All participants were given veridical feedback on their performance (ie, the average of the number of seconds they held each exercise).
The condition manipulation was introduced at this point. Participants in the individual control conditions simply rested for 10 minutes. Participants in the partner conditions were told that another participant was being run simultaneously at another lab on campus and that the 2 participants would be able to see one another over an Internet video connection during future trials. The participants then met briefly with that other same-sex participant in a controlled Skype-like interaction (we will refer to that other participant hereafter as “the partner”). In reality, the partner was an experimental confederate whose side of the interaction was prerecorded. After the interaction, participants were also given bogus feedback on how well the partner had done on the first trial. That feedback score was manipulated to be 1.4 times the participant’s own actual performance. This discrepancy was chosen based on previous research that suggests that this moderate discrepancy leads to the greatest increases in exercise duration (ie, the greatest Köhler effect) [
Participants were told that they and their partners would be a 2-person exercise team. In the encouragement condition, both teammates were told that they would have the opportunity to communicate with each other during the exercises but that, due to technical problems, this capability would be provided only for the partner. Thus, ostensibly both could speak, but only the partner would be heard by the subject. No mention was made of any audio link between partners in the no-encouragement condition. For both partner conditions, it was further explained that they were working towards a team score, where the team score would be the persistence score of the first teammate to quit an exercise (ie, as soon as either partner quit, the exercise was over). This task structure is more commonly known as a conjunctive task—when the group’s performance is defined by the performance of the least-capable member (ie, the “weak link”). Following these instructions, all participants responded again to the self-efficacy measure.
Block 2 then commenced. In the individual control condition, the participants could only see him/herself on the screen, as during Block 1. In the partner conditions, the participant could see the partner’s image (which was actually prerecorded) before and during the exercise; the participant believed that the partner could likewise see his/her (the participant’s) image. The images available to the participant suggested that s/he was always the first to quit each exercise. The video link was allegedly frozen as soon as either teammate quit an exercise and until just before the start of the next exercise; hence, the participant knew only that his/her partner had been able to persist longer, but not just how much longer. In the encouragement condition, a prerecorded series of phrases of encouragement was played through a set of computer speakers controlled by the experimenter. The phrases were audible approximately every 15s (±3s) and followed the following fixed progression: “you can do it”, “you got this”, “keep it going”, “you’re doing good”, “stay strong here”, “give it your best”. After Block 2 was over, the participant completed a series of questionnaires (self-efficacy, intention to exercise, enjoyment of physical activity, and manipulation checks). S/he was then debriefed, thanked, and excused.
Duration of exercise was measured via the total number of seconds that the exercise was held. Block scores were calculated by taking the summed total of the five exercises within each trial.
Task self-efficacy (SE) was measured with a scale developed specifically for this program of research using an online questionnaire. The measures contained five items, each corresponding to one of the five exercises within each trial. All items were preceded by the stem “What is the number of seconds that you are completely confident you can hold” followed by “The first exercise”, “the second exercise”, and so on for each of the five exercises. Respondents wrote in the number of seconds in a blank box following each item. The questionnaire was administered at three time points: once before Block 1 (after the participant had watched a brief instructional video demonstrating the exercises), a second time after Block 1 but before performing the five exercises at Block 2, and a third time after Block 2. A total SE score for each trial was calculated by taking the sum of the five items within each trial.
Ratings of perceived exertion (RPE) was measured using the 6-20 version of the Borg RPE scale [
Task enjoyment was measured using a short 8-item version of the Physical Activity Enjoyment Scale (PAES) using an online questionnaire [
Adapted from another measure [
Besides some questions checking participants’ understanding of the instructions and procedures, there were questions probing their perceived task ability, a rating of task difficulty, and a rating of effort expended on the task, each made on 8-point scales. Participants in the partner conditions were also asked to rate their partner’s relative ability on a 9-point scale (where 1=“I am much more capable” and 9=“my partner is much more capable”).
Following the methods of analyses done in earlier studies, exercise duration was taken as the sum of the time each participant held the five exercises within each block, producing a Block 1 and Block 2 score. There are, of course, individual differences in fitness, intrinsic task interest, and strength that we wished to control for. This can be done in different ways. In many prior studies [
The analyses of the exercise duration data was to proceed in two stages. The first was to check whether there were any history or cohort effects attributable to the interval between the two data collection waves. It employed a 2 (Condition: Individual vs partner-without-encouragement) x 2 (Sex) x 2 (Data collection wave: Early vs Late) ANOVA on exercise duration difference scores (ie, Trial 2 duration-Trial 1). Although overall sex differences in the magnitude of the Köhler effect are rare, some interesting sex effects have been reported, eg, [
Although our primary focus was on exercise duration, we also examined several other variables, primarily to determine if encouragement altered any of the effects previously observed [
Students were recruited from introductory psychology (online) and kinesiology courses (online and face-to-face) at a large Midwestern university and were given course credit for their participation. Students were recruited based on their interest in getting a good workout and were told that they would be playing an exercise video game and performing abdominal plank exercises for as long as they felt comfortable. The final total sample consisted of 115 participants (58 male, 57 female) college students (mean age 20.31, SD 3.26; see
As noted earlier, the participant pool and methods of recruitment were identical for the two waves of data collection, and participants were randomly assigned to conditions (single blind) within each wave using a randomization function on Microsoft Excel generated by one of the primary investigators. Hence, we expected rough equivalence in participant characteristics across waves and conditions. This could be checked for the two characteristics collected in the study—age and year in school. As expected, when the five combinations of wave and condition were compared in analyses of variance, there was no hint of between wave/condition differences (all
Participant flow.
The initial stage 1 analyses looked for possible history or cohort effects attributable to the interval between the two data collection waves. A boost in exercise duration (ie, the Köhler effect) was evident (Condition main effect
In the primary stage two analyses, the data for the Partner-with-encouragement condition was included to see whether and how adding verbal encouragement might affect the duration-boosting effect. The 3 (Condition: Individuals, Partner-without-encouragement, Partner-with-encouragement) x 2 (Sex) ANOVA on difference scores resulted in only one significant effect: the Condition main effect,
Condition Block 2 - Block 1 exercise duration means.
PostBlock efficacy judgments (sum of number of seconds participants estimated they could persist at all 5 exercises) were examined in a 2 (Block: postBlock 1, postBlock 2) x 3 (condition) x 2 (sex) ANCOVA, which used the preBlock 1 SE score as a covariate (ie, the participant’s estimated persistence at the five exercises collected prior to the first block of exercises). The latter should reflect and control for chronic individual differences in perceived self-efficacy at such exercises. As in previous studies, there was a Block main effect,
Two variables were relevant here—ratings of perceived exertion (RPE), averaged across exercises within blocks (for Block 1 alpha=.93, for Block 2 alpha=.96), and the postexperimental rating of effort expended at the task. A 2 (sex) x 3 (work condition) x 2 (block) analysis of the RPE data found that participants reported greater exertion at Block 2 (14.75; SD 1.97) than Block 1 (13.88, SD 1.89;
An overall task enjoyment measure was computed based on the 8 items of the PAES scale (alpha=.86). The grand mean (4.68, SD .97, on the 8-point scale) was not significantly different from the scale midpoint (4.5), suggesting that participants were, at worst, indifferent toward the exercise task. There were no significant effects in a 3 (condition) x 2 (sex) ANOVA of this measure—working harder at the task with a partner did not appear to undercut participants’ enjoyment of it. Participants’ postexperimental rating of the difficulty of the task suggested that they viewed it as moderately difficult (grand mean 4.90, SD 1.65, significantly above the scale midpoint,
Overall, at the end of the experimental session, participants expressed a positive intent to exercise for at least 30 minutes the following day. The grand mean was 1.61 (SD 1.70) on the 7-point scale anchored by -3 (“Not at all true for me”) to +3 (“Completely true for me”); this was significantly (
In the final questionnaire, participants were asked to rate their own ability (on an 8-point scale) and in the partner conditions, to rate their partner’s relative ability (on a 9-point scale where 0=“Not applicable. I didn’t have a partner”, 1=“I was much more capable” and 9=“My partner was much more capable”). A 3 (condition) x 2 (sex) ANOVA of own ability ratings produced a significant condition effect,
However, the encouragement manipulation did affect participants’ perceptions of their partner’s ability. A 2 (encouragement vs no-encouragement) x 2 (sex) ANOVA of partner relative ability ratings revealed a strong condition effect,
The purpose of this study was to test the efficacy of a superior Internet partner (with and without encouragement) as a strategy for increasing the duration of exercise. Consistent with previous studies [
The fact that encouragement attenuated the duration-boosting effect of being the weak link could be explained by a few competing explanations. First, at the outset of the study, we reasoned that receiving positive encouragement could bolster one’s self-efficacy [
Second, it was also possible that receiving encouragement from a superior other might be interpreted as condescending or patronizing [
One last possibility was that encouragement from a superior partner would be interpreted not as teammate support, but rather a method of self
There are a number of implications of this study for physical activity promotion. First, while many studies have shown the effectiveness of group-based approaches to physical activity promotion [
Of course, this study has its limitations. The study was conducted in a highly controlled laboratory setting, and it may be premature to suggest that these findings generalize to free-living conditions and other populations who are more physically inactive. Second, subjects were recruited through both face-to-face and web-based systems, and because we did not code participants for how they were recruited, we were unable to control for any individual differences between recruitment strategy (eg, being recruited via Internet may have selected for people who are more motivated to work out alone). Third, although we found that being the weak link can motivate participants to exercise longer, it is not clear if the same strategy could have the same positive impact on other dimensions of physical activity behavior (eg, frequency and intensity of exercise). Last, we tested participants in only one session of exercise, and repeatedly being the “weak link” over several sessions may actually be de-motivating [
The current study corroborates a growing body of research, which shows that exercising with a moderately superior Internet partner as the weak link can boost effort and lead to longer bouts of exercise [
Physical Activity Enjoyment Scale
ratings of perceived exertion
self-efficacy
The authors would like to acknowledge Nate Kenniston, Nick Thompson, Sam Forlenza, and Kaitlynn Sedabres for their help in conducting the study and David Dzewaltowski for his comments on an earlier draft of this manuscript.
None declared.
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