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Gallstone disease affects approximately 10-15% of the U.S. population, whereas the prevalence of physical inactivity in the U.S. is approximately 25%. While epidemiological studies have demonstrated a strengthened relation between physical inactivity and gallstone disease, the experimental research has yet to determine a clear underlying physiologic mechanism for such a relation. In this paper the association between physical activity and exercise to gallbladder function and gallstone disease will be examined. Recommendations for future research and the practical implications for the primary prevention of gallstone disease will also be discussed. [ABSTRACT FROM AUTHOR]

PURPOSE:: To evaluate the accuracy of ultrasound (ULTRA) in assessing fat-free mass (FFM) in comparison with hydrostatic weighing (HW) and skinfolds (SK) in high school wrestlers in a hydrated state. METHODS:: Body composition was determined by ULTRA, HW, and three-site SK in 70 high school wrestlers (mean +/- SD: age, 15.5 +/- 1.5; height, 1.60 +/- 0.08 m; body mass, 65.8 +/- 12.7 kg). For all methods, body density (Db) was converted to percent body fat (%BF) using the Brozek equation. Hydration state was quantified by evaluating urine specific gravity. RESULTS:: There were no significant differences for estimated FFM between ULTRA (57.2 +/- 9.7 kg) and HW (57.0 +/- 9.9 kg); however, SK (54.9 +/- 8.8 kg) were significantly different from HW. The standard errors of estimate for FFM with HW as the reference method were 2.40 kg for ULTRA and 2.74 kg for SK. Significant correlations were found for FFM between HW and ULTRA (r = 0.97, P < 0.001) and between HW and SK (r = 0.96, P < 0.001). A systematic bias was found for SK, as the difference between SK and HW significantly correlated with the FFM average of the two methods (r = -0.38, P < 0.001). This systematic bias was not found for ULTRA (r = - 0.07). CONCLUSIONS:: This study demonstrates that ULTRA provides similar estimates of FFM when compared with HW in a heterogeneous high school wrestling population during a hydrated state. ULTRA should be considered as an alternative field-based method of estimating the FFM of high school wrestlers. [ABSTRACT FROM AUTHOR]

PURPOSE: To evaluate the accuracy of leg-to-leg bioelectrical impedance analysis (BIA) in assessing fat-free mass (FFM) using the TBF-300WA in comparison with hydrostatic weighing (HW) and skinfolds (SK) in high-school (HS) wrestlers in a hydrated state. METHODS: Body composition was determined by BIA, HW, and three-site SK in 129 HS wrestlers (mean +/- SD, age: 15.5 +/- 1.3, height 1.70 +/- 0.08 m, body mass 65.6 +/- 13.1 kg). For all methods, body density (Db) was converted to percent body fat (%BF) using the Brozek equation. Hydration state was quantified by evaluating urine specific gravity. RESULTS: There were no significant differences for estimated FFM between BIA (56.9 +/- 8.4 kg) and HW (56.2 +/- 9.9 kg) or between SK (56.1 +/- 8.9 kg) and HW. The standard errors of estimate for FFM with HW as the reference method were 3.64 kg for BIA and 1.97 kg for SK. Significant correlations were found for FFM between HW and BIA (r = 0.93, P < 0.001), and between HW and SK (r = 0.98, P < 0.001). The FFM difference between BIA and HW was significantly correlated with the FFM average of the two methods (r = -0.39, P < 0.001). The FFM difference between SK and HW was also significantly correlated with the FFM average (r = -0.44, P < 0.001). CONCLUSIONS: This study demonstrates that SK should be considered as the preferred field method of estimating the FFM of HS wrestlers because of its greater individual precision than the leg-to-leg BIA method. Although the BIA is an attractive assessment tool and easy to use, it should be recommended as an alternative to the SK method only when trained skinfold technicians are not available. [ABSTRACT FROM AUTHOR]

PURPOSE: Concurrent and construct validity of the OMNI-Walk/Run Scale of Perceived Exertion was examined using young adult women and men (18-36 yr). METHODS: Concurrent validity was established by correlating OMNI-Walk/Run Scale ratings of perceived exertion (RPE-OMNI) with oxygen uptake (VO2), relative maximal oxygen uptake (%VO2(max)), ventilation (VE), respiratory rate (RR), respiratory exchange ratio (RER), and heart rate (HR) to a graded exercise test on a treadmill. Construct validity was established by correlating RPE-OMNI with RPE from the Borg (6-20) Scale (RPE-BORG). Measurements were made every min throughout the test. RESULTS: The range of exercise responses across the incremental walking/running test for the female and male groups were: VO2 = 0.99-3.9 L x min(-1), HR = 98-190 beats x min(-1) and RPE-OMNI = 1.3-9.4. Correlation/regression analyses indicated that RPE-OMNI distributed as a positive linear function for all criterion measures; r = 0.67 to 0.88 (P < 0.05). RPE-OMNI was positively and linearly related to the RPE-BORG; r = 0.96 (P < 0.01) for both the female and male groups. CONCLUSIONS: Concurrent and construct evidence supports use of the OMNI-Walk/Run Scale by adult women and men to estimate RPE during graded exercise test on a treadmill. [ABSTRACT FROM AUTHOR]

PURPOSE: The purpose of this study was to investigate the relationship between carbohydrate energy substrate and hormonal regulation on the perception of exertion during prolonged running. METHODS: Sixteen experienced marathoners ran on treadmills for 3 h at approximately 70% VO2max on two occasions while receiving 1 L x h carbohydrate (C) or placebo (P) beverages. Blood and vastus lateralis muscle biopsy samples were collected before and after exercise. RESULTS: The pattern of change in ratings of perceived exertion (RPE) over time was significantly different between C and P ingestion (P < 0.01) with attenuated RPE responses found in the latter part of the 3 h run. The pattern of change in the respiratory exchange ratio and carbohydrate oxidation rates were significantly greater (P < 0.01) in the C than P condition. Change in muscle glycogen content did not differ between C and P (P = 0.246). C relative to P ingestion was associated with higher plasma levels of glucose, insulin, and lactate and lower levels plasma cortisol. CONCLUSIONS: These data indicate that a lower RPE was associated with a higher carbohydrate oxidation, plasma glucose, and insulin levels, and lower plasma cortisol during prolonged running after C supplementation as compared with P feeding despite no differences in muscle glycogen content. These findings support a physiological link between RPE and carbohydrate substrate availability as well as selected hormonal regulation during prolonged running. [ABSTRACT FROM AUTHOR]

PURPOSE: To study the effect of carbohydrate compared to placebo ingestion on plasma cytokines and muscle cytokine mRNA following 2.5 h of intensive cycling in 15 trained cyclists. METHODS: Fifteen trained cyclists cycled for 2.5 h at 60% Wmax on two occasions while receiving 4 mL.kg.15 min carbohydrate (6%) (CHO) or placebo (PLA) beverages in a randomized, counterbalanced design. Blood and vastus lateralis muscle biopsy samples were collected before and after exercise and 12 h postexercise and compared to samples taken from five cyclists who rested in the lab during the exercise sessions. Blood cell counts were determined, and plasma was analyzed for interleukin (IL)-6, IL-10, IL-1 receptor antagonist (ra), IL-8, cortisol, epinephrine, glucose, and insulin. Muscle was analyzed for glycogen content and relative gene expression of four cytokines, IL-6, IL-8, tumor necrosis factor (TNF) alpha, and IL-1beta, using real-time quantitative reverse transcriptase polymerase chain reaction. RESULTS: Plasma glucose and insulin were higher, and epinephrine, cortisol, IL-6, IL-10, and IL-1ra, but not IL-8, were significantly lower postexercise in CHO versus PLA. Muscle glycogen content decreased 68% immediately postexercise and the pattern of change did not differ between CHO and PLA. Muscle IL-6, IL-8, TNF-alpha, but not IL-1beta mRNA increased immediately postexercise compared to controls, with no differences between CHO and PLA. CONCLUSION: CHO compared to PLA beverage ingestion attenuated the increase in plasma cortisol, epinephrine, IL-6, IL-10, and IL-1ra, but not muscle IL-6, IL-8, and TNF-alpha mRNA in athletes cycling 2.5 h at 60% Wmax. [ABSTRACT FROM AUTHOR]