Seasonal and spatial variability of nitrosamines and their precursor sources at a large-scale urban drinking water system.

Nitrosamines are considered to pose greater health risks than currently regulated DBPs and are subsequently listed as a priority pollutant by the EPA, with potential for future regulation. Denver Water, as part of the EPA's Unregulated Contaminant Monitoring Rule 2 (UCMR2) monitoring campaign, found detectable levels of N-nitrosodimethylamine (NDMA) at all sites of maximum residency within the distribution system. To better understand the occurrence of nitrosamines and nitrosamine precursors, Denver Water undertook a comprehensive year-long monitoring campaign. Samples were taken every two weeks to monitor for NDMA in the distribution system, and quarterly sampling events further examined 9 nitrosamines and nitrosamine precursors throughout the treatment and distribution systems. NDMA levels within the distribution system were typically low (>1.3 to 7.2 ng/L) with a remote distribution site (frequently >200 h of residency) experiencing the highest concentrations found. Eight other nitrosamines (N-nitrosomethylethylamine, N-nitrosodiethylamine, N-nitroso-di-n-propylamine, N-nitroso-di-n-butylamine, N-nitroso-di-phenylamine, N-nitrosopyrrolidine, N-nitrosopiperidine, N-nitrosomorpholine) were also monitored but none of these 8, or precursors of these 8 [as estimated with formation potential (FP) tests], were detected anywhere in raw, partially-treated or distribution samples. Throughout the year, there was evidence that seasonality may impact NDMA formation, such that lower temperatures (~5-10°C) produced greater NDMA than during warmer months. The year of sampling further provided evidence that water quality and weather events may impact NDMA precursor loads. Precursor loading estimates demonstrated that NDMA precursors increased during treatment (potentially from cationic polymer coagulant aids). The precursor analysis also provided evidence that precursors may have increased further within the distribution system itself. This comprehensive study of a large-scale drinking water system provides insight into the variability of NDMA occurrence in a chloraminated system, which may be impacted by seasonality, water quality changes and/or the varied origins of NDMA precursors within a given system.

Exercise dependence and muscle dysmorphia in novice and experienced female bodybuilders.

BACKGROUND AND AIMS: Extensive research has shown that male bodybuilders are at high risk for exercise dependence, but few studies have measured these variables in female bodybuilders. Prior research has postulated that muscular dysmorphia was more prevalent in men than women, but several qualitative studies of female bodybuilders have indicated that female bodybuilders show the same body image concerns. Only one study has compared female bodybuilders with control recreational female lifters on eating behaviors, body image, shape pre-occupation, body dissatisfaction, and steroid use. The purpose of this study was to compare exercise dependence and muscle dysmorphia measures between groups of female weight lifters. METHODS: Seventy-four female lifters were classified into three lifting types (26 expert bodybuilders, 10 or more competitions; 29 novice bodybuilders, 3 or less competitions; and 19 fitness lifters, at least 6 months prior lifting) who each completed a demographic questionnaire, the Exercise Dependence Scale (EDS), the Drive for Thinness scale (DFT) of the Eating Disorder Inventory-2, the Bodybuilding Dependence Scale (BDS), and the Muscle Dysmorphia Inventory (MDI). RESULTS: Female bodybuilders scored higher than fitness lifters for EDS Total, BDS Training and Social Dependence, and on Supplement Use, Dietary Behavior, Exercise Dependence, and Size Symmetry scales of the MDI. DISCUSSION AND CONCLUSIONS: Female bodybuilders seem to be more at risk for exercise dependence and muscle dysmorphia symptoms than female recreational weight lifters.

Grip width and forearm orientation effects on muscle activity during the lat pull-down.

Based on electromyographic (EMG) studies, an anterior (in front of the face) wide grip with a pronated forearm has been recommended as the optimal lat pull-down (LPD) variation for strengthening the latissimus dorsi (LD) (Signorile, JF, Zink, A, and Szwed, S. J Strength Cond Res 16: 539-546, 2002; Wills, R, Signorile, J, Perry, A, Tremblay, L, and Kwiatkowski, K. Med Sci Sports Exerc 26: S20, 1994). However, it is not clear whether this finding was because of grip width or forearm orientation. This study aimed to resolve this issue by comparing wide-pronated, wide-supinated, narrow-pronated, and narrow-supinated grips of an anterior LPD. Twelve healthy men performed the 4 grip variations using an experimentally determined load of 70% of 1 repetition maximum. Two trials of 5 repetitions were analyzed for each grip type. Participants maintained a cadence of 2-second concentric and 2-second eccentric phases. The grip widths were normalized for each individual by using a wide grip that corresponded to their carrying width and a narrow grip that matched their biacromial diameter. Surface EMG of the LD, middle trapezius (MT), and biceps brachii (BB) was recorded, and the root mean square of the EMG was normalized, using a maximum isometric voluntary contraction. Repeated-measures analysis of variance for each muscle revealed that a pronated grip elicited greater LD activity than a supinated grip (p < 0.05), but had no influence of grip type on the MT and BB muscles. Based on these findings, an anterior LPD with pronated grip is recommended for maximally activating the LD, irrespective of the grip width (carrying width or biacromial diameter).

Exercise dependence and the drive for muscularity in male bodybuilders, power lifters, and fitness lifters.

Researchers have hypothesized differences in exercise dependence and drive for muscularity between bodybuilders and power lifters, while others have not found the predicted differences. This study assessed 146 weight lifters (bodybuilders, n=59; power lifters, n=47; fitness lifters, n=40) on the Exercise Dependence Scale, Bodybuilding Dependence Scale, and the Drive for Muscularity Scale. Results showed that bodybuilders and power lifters were significantly higher than fitness lifters on EDS Total, 7 EDS scales, and the 3 BDS scales. In contrast, power lifters were found to be significantly higher on DMS Total and DMS Behavior scales than bodybuilders. The regression results suggest that exercise dependence may be directly related to the drive for muscularity.

Competitive state anxiety and self-confidence: intensity and direction as relative predictors of performance on a golf putting task.

This study considered relationships between the intensity and directional aspects of competitive state anxiety as measured by the modified Competitive Sport Anxiety Inventory-2(D) (Jones & Swain, 1992) in a sample of 12 experienced male golfers. Anxiety and performance scores from identical putting tasks performed under three different anxiety-manipulated competitive conditions were used to assess both the predictions of Multidimensional Anxiety Theory (MAT; Martens et al., 1990) and the relative value of intensity and direction in explaining performance variance. A within-subjects regression analysis of the intra-individual data showed partial support for the three MAT hypotheses. Cognitive anxiety intensity demonstrated a negative linear relationship with performance, somatic anxiety intensity showed a curvilinear relationship with performance, and self-confidence intensity revealed a positive linear relation. Cognitive directional anxiety illustrated a positive linear relationship with putting performance. Multiple regression analyses indicated that direction (42% of variance) was a better predictor of performance than intensity (22%).