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Christopher Mesagno, Jack T. Harvey and Christopher M. Janelle

Whether self-presentation is involved in the choking process remains unknown. The purpose of the current study was to determine the role of self-presentation concerns on the frequency of choking within the context of a recently proposed self-presentation model. Experienced field hockey players (N = 45) were randomly assigned to one of five groups (i.e., performance-contingent monetary incentive, video camera placebo, video camera self-presentation, audience, or combined pressure), before taking penalty strokes in low- and high-pressure phases. Results indicated that groups exposed to self-presentation manipulations experienced choking, whereas those receiving motivational pressure treatments decreased anxiety and increased performance under pressure. Furthermore, cognitive state anxiety mediated the relationship between the self-presentation group and performance. These findings provide quantitative support for the proposed self-presentation model of choking, while also holding implications for anxiety manipulations in future sport psychology research.

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Adam M. Bruton, Stephen D. Mellalieu and David A. Shearer

The purpose of this multistudy investigation was to examine observation as an intervention for the manipulation of individual collective efficacy beliefs. Study 1 compared the effects of positive, neutral, and negative video footage of practice trials from an obstacle course task on collective efficacy beliefs in assigned groups. The content of the observation intervention (i.e., positive, neutral, and negative video footage) significantly influenced the direction of change in collective efficacy (p < .05). Study 2 assessed the influence of content familiarity (own team/sport vs. unfamiliar team/sport) on individual collective efficacy perceptions when observing positive footage of competitive basketball performance. Collective efficacy significantly increased for both the familiar and unfamiliar conditions postintervention, with the largest increase for the familiar condition (p < .05). The studies support the use of observation as an intervention to enhance individual perceptions of collective efficacy in group-based activities. The findings suggest that observations of any group displaying positive group characteristics are likely to increase collective efficacy beliefs; however, observation of one’s own team leads to the greatest increases.

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Leanna Ferrand and Slobodan Jaric

The purpose of this study was to explore the effects of handedness on coordination of grip (G) and load (L) forces in static bimanual manipulation tasks. Participants (N = 10) exerted various L profiles against an externally fixed hand-held device based on presumably open-loop and closed-loop neural control mechanisms, (i.e., mediated and not mediated, respectively, by sensory feedback). Average G/L ratio and the coupling of G and L (i.e., stability of the G/L ratio and correlation between G and L) were separately assessed in each hand. The results revealed a lower average G/L ratio in the non-dominant hand suggesting a more economical grip, while the indices of G and L coupling were similar in two hands. The dominant and non-dominant hand failed to reveal relative advantages in the tasks predominantly based on open- and closed-loop control mechanisms, respectively. We conclude that, due to the static nature of the tested tasks, the particular advantage of the non-dominant hand in G and L coordination could be in line with the recently proposed specialization of the non-dominant limb for control of position. However, the overall results are not in line with classic views of the prevailing open- closed-loop neural mechanisms in the control of the dominant and nondominant limb, respectively.

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Vennila Krishnan, Paulo Barbosa de Freitas and Slobodan Jaric

We investigated hand function in mildly involved multiple sclerosis (MS) patients (N = 16; Expanded Disability Status Scale 1–5, 9-hole peg test 14–32 s) during static and dynamic manipulation tasks using an instrumented device. When compared with healthy controls (N = 16), the patients revealed impaired task performance regarding their ability to exert prescribed patterns of load force (L; force acting tangentially at the digits-object surface). Regarding the coordination of grip force (G; normal component) and L, the data only revealed an elevated G/L ratio, although both the G and L coupling (maximum correlation coefficients and the time lags between them) and the G modulation (gain and offset of G with respect to L) remained comparable in the two groups. Finally, most of the data suggested no MS-specific effects of switching from uni- to bimanual tasks, from available visual feedback to deprived feedback conditions. We conclude that the deterioration in the ability for precise control of external forces and overgripping could precede the decoupling of G and L and decreased G modulation in early phases of the disease. The results also suggest that the applied methodology could be sensitive enough to detect mild levels of impairment of hand function in MS and, possibly, other neurological diseases.

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Liang Hu, Shoubin Cheng, Jiaying Lu, Lele Zhu and Ling Chen

Purpose:

In this study, we examined the effect of the manipulation of exercise self-efficacy on the enjoyment of physical activity in a sample of 44 Chinese adolescents (age = 14.27 ± .87 y), including 22 boys and 22 girls.

Methods:

The participants were randomized into a low-efficacy or high-efficacy condition, and their self-efficacy beliefs for engaging in moderate-intensity physical activity were manipulated by providing false feedback after a submaximal exercise test. The participants’ self-efficacy was measured and compared before and after the exercise test and the participants’ enjoyment of physical activity was assessed after the exercise test.

Results:

It was found that exercise self-efficacy was successfully manipulated in the expected direction in both conditions, which significantly influenced the participants’ enjoyment of physical activity. After the exercise test, the participants in the low-efficacy condition reported lower enjoyment scores relative to the high-efficacy participants.

Conclusions:

These results suggest that self-efficacy may have an important influence on the enjoyment of physical activity among Chinese adolescents. We recommend that physical activity promotion programs should be tailored to enhance adolescents’ self-efficacy beliefs and enjoyment of the experience of physical activity.

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Mark H. Roltsch, Judith A. Flohr and Patricia B. Brevard

The purpose of this study was to examine the metabolic consequences of a moderate variation in dietary fat content of male endurance athletes during submaximal exercise. Six males (age, 29.8 ± 11 years; weight, 72.3 ± 10 kg) · with an average maximum oxygen uptake (V̇O2max) of 66 ± 10 ml/kg/min were tested on their normal diet and 3 experimental diets. The energy contributions from protein, carbohydrates, and fats were 16/59/22 (3% alcohol), 14/53/33, 13/72/15, and 16/61/23% for the normal diet (N), fat supplemented diet (F), high carbohydrate diet (C), and adjusted normal diet (AN), respectively. The F diet was designed to significantly increase fat content compared to the normal diet and be easily maintained by the athletes. Caloric content of the F, C, and AN diets were adjusted to meet estimated total daily energy expenditure. The difference between the N and AN diets is that the AN has been adjusted to meet estimated total daily energy expenditure. The diets were randomly assigned after substrate utilization testing on the N diet and were consumed for 7 days prior to testing. Substrate utilization was recorded at steady state (73 ± 1.4% of V̇O2max) while running on a treadmill for 40 min. There were no significant differences in respiratory exchange ratio between any of the dietary manipulations. No significant differences were observed for lactate, V̇O2, or HR during submaximal testing on the N, F, C, and AN diets. These data indicate that a fat supplemented diet did not affect substrate utilization during 40 min of steady-state submaximal exercise when compared to a high carbohydrate diet or the participant’s normal and adjusted normal diets.

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Anthony J. Lisi, Conor W. O’Neill, Derek P. Lindsey, Robert Cooperstein, Elaine Cooperstein and James F. Zucherman

This paper presents the first reported measurements of lumbar intervertebral disc pressure in vivo during spinal manipulation. A pressure transducer was inserted into the nucleus pulposus of one normal-appearing lumbar disc in an asymptomatic adult volunteer. Pressures were recorded during several body positions and maneuvers, then during spinal manipulation, and lastly during a repetition of the preintervention body positions. Baseline pressures in the prone and side-lying positions measured 110 kPa and 150 kPa, respectively. During the manipulation, pressure rose to a peak of 890 kPa over 250 ms. Immediately following, pressures in the prone and side-lying positions measured 150 kPa and 165 kPa, respectively. These data do not support the hypotheses that manipulation can reduce a herniation by decreasing intradiscal pressure, or cause a herniation by raising pressure to failure levels. Further work may lead to a better understanding of this treatment method.

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Laura Yan Lan and Diane L. Gill

The influence of self-efficacy on physiological arousal and self-reported anxiety was examined in the first phase of this study. All 32 undergraduate females in the study performed five trials of both an easy task and a difficult task, with half of them performing the easy task first and half performing the difficult task first. A manipulation check revealed that the easy task clearly elicited higher self-efficacy than the difficult task. Individuals reported lower cognitive and somatic anxiety and higher self-confidence, as assessed with the CSAI-2, and had lower heart-rate increases when performing the easy (high-efficacious) task. After the subjects finished both the easy and difficult tasks, half of them were given a cognitive feedback manipulation suggesting that elevated arousal levels were typical responses of good competitors under stress. Contrary to predictions, the manipulation did not induce higher self-efficacy and the manipulation group did not differ from the no-manipulation group on self-reported anxiety scores or heart rates. The findings support Bandura's contention that self-efficacy mediates arousal changes and demonstrate the influence of self-efficacy on multidimensional anxiety measures, but fail to demonstrate any influence of a cognitive feedback manipulation on self-efficacy or subsequent stress responses.

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Sabrina Skorski, Oliver Faude, Chris R. Abbiss, Seraina Caviezel, Nina Wengert and Tim Meyer

Purpose:

To date, there has been limited research examining the influence of pacing pattern (PP) on middle-distance swimming performance. As such, the purpose of the current study was to examine the influence of PP manipulation on 400-m freestyle swimming performance.

Methods:

15 front-crawl swimmers (5 female, 10 male; age 18 ± 2 y) performed 3 simulated 400-m swimming events. The initial trial was self-selected pacing (PPSS). The following 2 trials were performed in a counterbalanced order and required participants to complete the first 100 m more slowly (PPSLOW: 4.5% ± 2.2%) or quickly (PPFAST: 2.4% ± 1.6%) than the PPSS trial. 50-m split times were recorded during each trial.

Results:

Overall performance time was faster in PPSS (275.0 ± 15.9 s) than in PPFAST (278.5 ± 16.4 s, P = .05) but not significantly different from PPSLOW (277.5 ± 16.2 s, P = .22). However, analysis for practical relevance revealed that pacing manipulation resulted in a “likely” (>88.2%) decrease in performance compared with PPSS.

Conclusion:

Moderate manipulation of the starting speed during simulated 400-m freestyle races seems to affect overall performance. The observed results indicate that PPSS is optimal in most individuals, yet it seems to fail in some swimmers. Future research should focus on the identification of athletes possibly profiting from manipulations.

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Mehmet Uygur, Goran Prebeg and Slobodan Jaric

We compared two standard methods routinely used to assess the grip force (GF; perpendicular force that hand exerts upon the hand-held object) in the studies of coordination of GF and load force (LF; tangential force) in manipulation tasks. A variety of static tasks were tested, and GF-LF coupling (i.e., the maximum cross-correlation between the forces) was assessed. GF was calculated either as the minimum value of the two opposing GF components acting upon the hand-held object (GFmin) or as their average value (GFavg). Although both methods revealed high GF-LF correlation coefficients, most of the data revealed the higher values for GFavg than for GFmin. Therefore, we conclude that the CNS is more likely to take into account GFavg than GFmin when controlling static manipulative actions as well as that GFavg should be the variable of choice in kinetic analyses of static manipulation tasks.