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John Pates and Kieran Kingston

. Typically, I would have players playing in the morning “draw” and afternoon draw, and the draw for the tournament tee times would change from day to day. This meant that my daily routine would have to change accordingly. This often creates additional pressures for both the athlete and the consultant and

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Daniel J. Brown, Rachel Arnold, Martyn Standage and David Fletcher

century. Early descriptions of thriving in sport emerged from conceptual investigations on mental toughness in elite athletes (see Bull, Shambrook, James, & Brooks, 2005 ; Jones, Hanton, & Connaughton, 2002 ). Within these studies, thriving on the pressure of competition was described as a key attribute

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Diego Augusto Santos Silva, Mark Tremblay, Andreia Pelegrini, Roberto Jeronimo dos Santos Silva, Antonio Cesar Cabral de Oliveira and Edio Luiz Petroski

Purpose:

Criterion-referenced cut-points for health-related fitness measures are lacking. This study aimed to determine the associations between aerobic fitness and high blood pressure levels (HBP) to determine the cut-points that best predict HBP among adolescents.

Method:

This cross-sectional school-based study with sample of 875 adolescents aged 14–19 years was conducted in southern Brazil. Aerobic fitness was assessed using the modified Canadian Aerobic Fitness Test (mCAFT). Systolic and diastolic blood pressure were measured by the oscillometric method with a digital sphygmomanometer. Analyses controlled for sociodemographic variables, physical activity, body mass and biological maturation.

Results:

Receiver Operating Characteristic (ROC) curves demonstrated that mCAFT measures could discriminate HBP in both sexes (female: AUC = 0.70; male: AUC = 0.63). The cut-points with the best discriminatory power for HBP were 32 mL·kg-1·min-1 for females and 40 mL·kg-1·min-1 for males. Females (OR = 8.4; 95% CI: 2.1, 33.7) and males (OR: 2.5; CI 95%: 1.2, 5.2) with low aerobic fitness levels were more likely to have HBP.

Conclusion:

mCAFT measures are inversely associated with BP and cut-points from ROC analyses have good discriminatory power for HBP.

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Christoph Dehner, Andreas Schmelz, Hans-Ullrich Völker, Jochen Pressmar, Martin Elbel and Michael Kramer

Context:

Chronic low back pain (LBP) has been reported with a high incidence in elite rowers. It results in less effective training, long interruptions in training, and a drop in performance.

Objective:

The authors hypothesized that exercise-induced LBP in rowers is caused by a chronic functional compartment syndrome (CFCS) of the multifidus muscle.

Design:

Controlled clinical trial.

Setting:

The rowers were tested in their training camp. The control group was tested at a university hospital.

Participants:

14 volunteer elite rowers complaining of LBP and 16 healthy volunteer amateur athletes.

Main Outcome Measurements:

Intramuscular pressure (IMP), tissue oxygenation pressure (pO2), and median frequency (MF) shift in the electromyographic power density spectrum during isometric fatiguing extension at 60% of maximum voluntary contraction.

Results:

At the beginning (controls 186.6 mm Hg vs rowers 60.2 mm Hg, P = .002) and the end (controls 224.1 mm HG vs rowers 77.1 mm Hg, P < .001) of the endurance exercise the median IMP was significantly higher in the healthy controls. Nearly identical resting pO2 was measured in both groups (controls 37.6 mm Hg vs rowers 37.3 mm Hg, P = .740). Rowers showed higher median MF shift (rowers −11.5 Hz vs controls −8.5 Hz, P = .079) during contraction.

Conclusions:

These observations cannot sufficiently be explained by the CFCS model and suggest that factors other than IMP have an additional effect on pain generation during exercise in elite rowers.

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Liana Tennant, David Kingston, Helen Chong and Stacey Acker

Occupational kneeling is associated with an increased risk for the development of knee osteoarthritis. Previous work studying occupational kneeling has neglected to account for the fact that in many industrial settings, workers are required to wear steeltoe work boots. Thus, the purpose of this study was to evaluate the effect of work boot wear on the center of pressure location of the ground reaction force, knee joint angle, and magnitude of the ground reaction force in a kneeling posture. Fifteen healthy males were fit with 3D motion capture markers and knelt statically over a force plate embedded in the floor. Using the tibial tuberosity as the point of reference, the center of pressure in shod condition was shifted significantly medially (on average 0.009 m [P = .005]) compared with the barefoot condition. The knee was significantly less internally rotated (shod: –12.5° vs. barefoot: –17.4° [P = .009]) and the anterior/posterior shear force was significantly greater in the shod condition (shod: 6.0% body weight vs. barefoot: 1.5% body weight [P = .002]). Therefore, wearing work boots alters the kneeling posture compared with barefoot kneeling, potentially loading different surfaces of the knee, as well as altering knee joint moments.

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Kathleen F. Janz and Larry T. Mahoney

To assess the relationship of changes in physical fitness and body composition to heart growth and rising blood pressure (BP) during early puberty, fat-free mass (FFM), body fatness (% fat), physical fitness (peak VO2, peak mechanical power, peak O2 pulse, peak systolic blood pressure [SBP], and grip strength), Tanner stage, resting BP, and echocardiographic left ventricular mass (LVM) were measured in 123 children (age M = 10 years) and remeasured 2 years later. Increased FFM, increased grip strength, and increased peak power explained 28% of the variability in heart growth. Increased FFM, increased % fat, and decreased peak O2 pulse explained 23% of the variability in rising SBP. During puberty, physical fitness is an independent predictor of changing heart size and systolic blood pressure. Results suggest that improvements in physical fitness and decreases in body fatness may have beneficial effects on children’s blood pressure.

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Masashi Miyashita, Stephen Francis Burns and David John Stensel

Background:

This study examined the effect of accumulating short bouts of exercise on postprandial plasma triacylglycerol and resting blood pressure in healthy young men.

Methods:

Nineteen subjects underwent two 2-d trials in a randomized counterbalanced order. On day 1, subjects either rested or performed multiple 6 min running bouts (30 min rest between each) until they had accumulated an energy expenditure of 4.2 MJ (1000 kcal). On day 2, subjects rested and consumed test meals for breakfast and lunch. Blood pressure was measured throughout days 1 and 2. Venous blood samples were obtained throughout day 2.

Results:

Systolic and diastolic blood pressure was lower for the exercise compared with the control trial on day 1. Postprandial plasma triacylglycerol concentrations and systolic blood pressure were lower throughout day 2 on the exercise compared with the control trial.

Conclusion:

Accumulating short bouts of exercise throughout the day may modify cardiovascular disease risk.

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Kenneth R. Turley, D. Eric Martin, Eric D. Marvin and Kelley S. Cowley

To determine the reliability of cardiovascular responses to isometric exercise of different intensities, and to compare adult versus child responses, 27 boys (7–9 years old) and 27 men (18–26 years old) performed static handgrip exercise at 10, 20, and 30% of previously determined maximal voluntary contraction (MVC) for three min each on different days, while heart rate (HR) and blood pressure (BP) were measured. HR reliability was moderately high at all intensities in both boys and men ranging from R = 0.52–0.87. BP reliability was moderate in men and boys at 30% MVC while at 10% and 20% MVC reliability was very low for boys and only moderate for men. HR response from pre- to 3-min of static exercise was not different between boys versus men at any intensity. At 30% MVC diastolic (20.2 vs. 29.3 mmHg), systolic (17.4 vs. 36.2 mmHg) and mean (19.2 vs. 31.6 mmHg) BP responses were lower in boys versus men, respectively. At 20% MVC SBP (6.8 vs. 14.3 mmHg) and MBP (8.4 vs. 12.6 mmHg) responses were lower in boys versus men, respectively. In conclusion, the reliability of cardiovascular response to isometric exercise is low at low contraction intensities and moderate at higher contraction intensities. Further, BP response in men at 30% MVC is higher than boys, while responses are similar at lower contraction intensities.

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Bente R. Jensen, Line Hovgaard-Hansen and Katrine L. Cappelen

Running on a lower-body positive-pressure (LBPP) treadmill allows effects of weight support on leg muscle activation to be assessed systematically, and has the potential to facilitate rehabilitation and prevent overloading. The aim was to study the effect of running with weight support on leg muscle activation and to estimate relative knee and ankle joint forces. Runners performed 6-min running sessions at 2.22 m/s and 3.33 m/s, at 100%, 80%, 60%, 40%, and 20% body weight (BW). Surface electromyography, ground reaction force, and running characteristics were measured. Relative knee and ankle joint forces were estimated. Leg muscles responded differently to unweighting during running, reflecting different relative contribution to propulsion and antigravity forces. At 20% BW, knee extensor EMGpeak decreased to 22% at 2.22 m/s and 28% at 3.33 m/s of 100% BW values. Plantar flexors decreased to 52% and 58% at 20% BW, while activity of biceps femoris muscle remained unchanged. Unweighting with LBPP reduced estimated joint force significantly although less than proportional to the degree of weight support (ankle).It was concluded that leg muscle activation adapted to the new biomechanical environment, and the effect of unweighting on estimated knee force was more pronounced than on ankle force.

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Martin J. Turner, Marc V. Jones, David Sheffield, Matthew J. Slater, Jamie B. Barker and James J. Bell

This study assessed whether cardiovascular (CV) reactivity patterns indexing challenge and threat states predicted batting performance in elite male county (N = 12) and national (N = 30) academy cricketers. Participants completed a batting test under pressure, before which CV reactivity was recorded in response to ego-threatening audio instructions. Self-reported self-efficacy, control, achievement goals, and emotions were also assessed. Challenge CV reactivity predicted superior performance in the Batting Test, compared with threat CV reactivity. The relationships between self-report measures and CV reactivity, and self-report measures and performance were inconsistent. A small subsample of participants who exhibited threat CV reactivity, but performed well, reported greater self-efficacy than participants who exhibited threat CV reactivity, but performed poorly. Also a small subsample of participants who exhibited challenge reactivity, but performed poorly, had higher avoidance goals than participants with challenge reactivity who performed well. The mechanisms for the observed relationship between CV reactivity and performance are discussed alongside implications for future research and applied practice.