The aim of this study was to compare the plantar pressures and forces recorded from both feet of two groups of javelin throwers of different performance levels, in order to investigate differences between skill levels. The study was carried out using an EMED insole system on a Tartan javelin runway at the University of Innsbruck, Austria. Most of the differences (at p < .01) between the two groups were found in the two foot contacts during the delivery stride. Higher maximum total forces (forces on the whole foot) and maximum pressures were recorded for the more skilled or club throwers during the right foot contact at the beginning of this stride. For the left foot landing before release, the club throwers exhibited higher overall maximum forces and overall pressures (the largest forces and pressures recorded on any of the different foot regions) than the novices. The differences between the groups in the medial forefoot region contributed significantly to this result.
Roger Bartlett, Erich Müller, Christian Raschner, Stefan Lindinger and Caroline Jordan
Justine J. Reel, Sonya SooHoo, Trent A. Petrie, Christy Greenleaf and Jennifer E. Carter
Previous research with female athletes has yielded equivocal findings when comparing disordered eating rates to nonathlete populations, but the rates differ for athletes in leanness and nonleanness sports (Sherman & Thompson, 2009). The purpose of the current study was to develop a measure to assess sport-specific weight pressures for female athletes. Secondly, this study identified frequencies of weight, size, and appearance pressures across sports. Participants (N =204) were female Division I athletes from three universities who represented 17 sports. Exploratory factor analysis yielded a 4-factor solution for the 16-item Weight Pressures in Sport for Females (WPS-F) scale with strong internal consistency (Cronbach’s alpha of 0.90). The most frequently reported pressures among female college athletes were teammates (36.8%), uniform (34.3%), and coach (33.8%). These findings are discussed in comparison with previous research along with clinical and research implications for using the WPS-F in sport psychology settings.
Choking research in sport has suggested that an athlete's tendency to choke, versus give a better than usual (i.e., “clutch”) performance depends on his or her personality, as well as on situational influences, such as a reliance on explicit (versus implicit) knowledge when pressured. The current study integrated these hypotheses and tested a structural equation model (SEM) to predict sport performance under pressure. Two hundred and one participants attempted two sets of 15 basketball free throws, and were videotaped during their second set of shots as a manipulation of pressure. Results of the model suggest that “reinvesting” attention in the task leads to greater anxiety (cognitive and somatic), which then predicts a higher level of self-focus; self-focus, then, did not lead to improved performance under pressure, whereas feelings of self-reported “perceived control” did help performance. Implications for measurement of these constructs, and their relationships with performance, are discussed.
George A. Kelley and Kristi S. Kelley
The purpose of this study was to use the meta-analytic approach to examine the effects of exercise on resting systolic and diastolic blood pressure in children and adolescents. Twenty-five studies that included 84 groups (45 exercise, 39 control) and 3,189 subjects (1,885 exercise, 1,304 control) met the criteria for inclusion. Using a random effects model, non-significant decreases of approximately 2% were found for resting systolic (mean – SEM, –2 – 1 mmHg, 95% CI, –4 to 1 mmHg) and diastolic (mean – SEM, –1 – 1 mmHg, 95% CI, –3 to 1 mmHg) blood pressure. Greater decreases in resting systolic blood pressure were found for nonrandomized versus randomized controlled trials (p = 0.001). There was also a statistically significant association between changes in resting systolic blood pressure and initial blood pressure (r = 0.73, p < 0.001) and body weight (r = 0.64, p < 0.001). However, when limited to randomized trials, these results were no longer statistically significant. The results of this study suggest that exercise does not reduce resting systolic and diastolic blood pressure in children and adolescents. However, a need exists for additional randomized controlled trials, especially among hypertensive children and adolescents.
Carmelo Bazzano, Lee N. Cunningham, Giustino Varrassi and Tony Falconio
The present study examined the relationships among the AAHPERD Physical Best health related physical fitness test (HRPFT) items to resting blood pressure in 80 boys and 84 girls from the Lanciano, Italy, school system. Systolic blood pressure (SBP) was significantly associated with age for both sexes. Diastolic blood pressure (DBP) for boys was found to be associated with fatness when age was held constant. To examine the relationship between blood pressure and the HRPFT, data were sorted into two groups of students passing or failing to meet the criterion-referenced standard (CRS) by 1-mile run performance and sum of skinfolds. SBP did not differ significantly between groups for either sex. Boys who failed to meet the CRS for 1-mile run performance showed a higher DBP of 4 mmHg when compared to boys who achieved the CRS. The group passing the aerobic fitness and body composition tests tended to perform better on all test items. With the possible exception of DBP for boys, it is concluded that performance on the Physical Best HRPFT is not associated with resting blood pressure in children and adolescents.
O. Girard, J.-P. Micallef and G.P. Millet
This study aimed at examining the influence of different playing surfaces on in-shoe loading patterns in each foot (back and front) separately during the first serve in tennis.
Ten competitive tennis players completed randomly five frst (ie, fat) serves on two different playing surfaces: clay vs GreenSet. Maximum and mean force, peak and mean pressure, mean area, contact area and relative load were recorded by Pedar insoles divided into 9 areas for analysis.
Mean pressure was significantly lower (123 ± 30 vs 98 ± 26 kPa; -18.5%; P < .05) on clay than on GreenSet when examining the entire back foot. GreenSet induced higher mean pressures under the medial forefoot, lateral forefoot and hallux of the back foot (+9.9%, +3.5% and +15.9%, respectively; both P < .01) in conjunction with a trend toward higher maximal forces in the back hallux (+15.1%, P = .08). Peak pressures recorded under the central and lateral forefoot (+21.8% and +25.1%; P < .05) of the front foot but also the mean area values measured on the back medial and lateral midfoot were higher (P < .05) on clay. No significant interaction between foot region and playing surface on relative load was found.
It is suggested that in-shoe loading parameters characterizing the first serve in tennis are adjusted according to the ground type surface. A lesser asymmetry in peak (P < .01) and mean (P < .001) pressures between the two feet was found on clay, suggesting a greater need for stability on this surface.
Patrick F. Curran, Russell D. Fiore and Joseph J. Crisco
Self-myofascial release (SMR) is a technique used to treat myofascial restrictions and restore soft-tissue extensibility.
To determine whether the pressure and contact area on the lateral thigh differ between a Multilevel rigid roller (MRR) and a Bio-Foam roller (BFR) for participants performing SMR.
Ten healthy young men and women.
Participants performed an SMR technique on the lateral thigh using both myofascial rollers. Thin-film pressure sensels recorded pressure and contact area during each SMR trial.
Mean sensel pressure exerted on the soft tissue of the lateral thigh by the MRR (51.8 ± 10.7 kPa) was significantly (P < .001) greater than that of the conventional BFR (33.4 ± 6.4 kPa). Mean contact area of the MRR (47.0 ± 16.1 cm2) was significantly (P < .005) less than that of the BFR (68.4 ± 25.3 cm2).
The significantly higher pressure and isolated contact area with the MRR suggest a potential benefit in SMR.
Juliane P. Hernandez, Kristin Roever and Tonya Seed
This investigation attempted to determine whether heart-rate and blood pressure responses to maximal acute lower body negative pressure (LBNP) are exacerbated compared with maximal graded LBNP in active older (n = 9, 70 ± 7 yr) and endurance-trained younger (n = 10, 23 ± 3 yr) individuals. Heart rate increased earlier during graded LBNP in the younger group (−40 mm Hg vs. tolerance) and was significantly higher than that of the older adults at the point of tolerance. Mean arterial pressure (MAP) decreased more in the older than the younger individuals during graded LBNP. LBNP-tolerance index was significantly greater in the younger group (309 ± 52 vs. 255.6 ± 48 mm Hg/min). Acute doses of LBNP elicited slower heart-rate responses in the older group. Despite these age-related differences, MAP responses were not different between groups with acute LBNP, so age per se does not appear to predispose individuals to orthostatic intolerance.
Tim Berrett and Trevor Slack
Sport sponsorship is frequently described as a strategic activity, and thus, it is influenced by both competitive and institutional forces. Using a sample of 28 Canadian companies, this study explores the influence of competitive and institutional pressures on those individuals who make decisions about their company's sport sponsorship initiatives. The results show that the sponsorship activities of rival companies were influential in a company's sponsorship choices. This was particularly the case in highly concentrated industries. We also show some evidence of a first-mover advantage in sponsorship decision-making but found preemptive strategies to yield little competitive advantage. In addition to these pressures from the competitive environment, institutional pressures from companies in the same geographic area, in the form of mimetic activity, in the form of involvement in social networks, and through the occupational training of the decision makers—all played a role in the choices made about what activities to sponsor.
Riann M. Palmieri, Christopher D. Ingersoll, Marcus B. Stone and B. Andrew Krause
To define the numerous center-of-pressure derivatives used in the assessment of postural control and discuss what value each might provide in the assessment of balance.
MEDLINE and SPORTDiscus were searched with the terms balance, postural control, postural sway, and center of pressure. The remaining citations were collected from references of similar papers. A total of 67 references were studied.
Understanding what is represented by each parameter used to assess postural control is crucial. At the present time the literature has failed to demonstrate how the variables reflect changes made by the postural-control system. Until it can be shown that the center of pressure and its derivatives actually reveal changes in the postural-control system, the value of using these measures to assess deficits in postural control is minimized.