Prediction of segmental lean mass using anthropometric variables in young adults

Abstract

The aim of the present study was to develop and cross-validate anthropometrical prediction equations for segmental lean tissue mass (SLM). One hundred and seventeen young healthy Caucasians (67 men and 50 women; mean age: 31.9 ± 10.0 years; Body Mass Index: 24.3 ± 3.2 kg · m^?2) were included. Body mass (BM), stretch stature (SS), 14 circumferences (CC), 13 skinfolds (SF) and 4 bone breadths (BB) were used as anthropometric measurements. Segmental lean mass of both arms, trunk and both legs were measured by dual energy X-ray absorptiometry as the criterion method. Three prediction equations for SLM were developed as follows: arms = 40.394(BM) + 169.836(CCarm-tensed) + 399.162(CCwrist) – 85.414(SFtriceps) – 39.790(SFbiceps) – 7289.190, where Adj.R ² = 0.97, P < 0.001, and standard error of estimate (SEE) = 355 g;trunk = 181.530(BM) + 155.037(SS) + 534.818(CCneck) + 175.638(CCchest) ? 88.359(SFchest) ? 147.232(SFsupraspinale) ? 46522.165, where Adj.R ² = 0.97, P < 0.001, and SEE = 1077g; and legs = 55.838(BM) + 88.356(SS) + 235.579(CCmid-thigh) + 278.595(CCcalf) + 288.984(CCankle) ? 84.954(SFfront-thigh) ? 53.009(SFmedial calf) ? 28522.241, where Adj.R ² = 0.96, P < 0.001, and SEE = 724 g. Cross-validation statistics showed no significant differences (P < 0.05) between observed and predicted SLM. Root mean squared errors were smallest for arms (362 g), followed by legs (820 g) and trunk (1477 g). These new prediction equations allow an accurate estimation of segmental lean mass in groups of young adults, but estimation errors of 8 to 14% can occur in certain individuals.     

Moral disengagement and associated processes in performance-enhancing drug use: a national qualitative investigation

Abstract

This study investigated psychosocial processes associated with avoidance of health- and morality-based deterrents to performance-enhancing drug (PED) use. In-depth semi-structured interviews were conducted with 64 English male bodybuilders with experience of doping. Resultant data were content analysed deductively using definitions for the eight mechanisms of moral disengagement (MD; Bandura, A. (1991). Social cognitive theory of moral thought and action. In W. M. Kurtines & J. L. Gewirtz (Eds.), Handbook of moral behavior and development: Theory research and applications (pp. 71–129). Hillsdale, NJ: Lawrence Erlbaum Associates.), and three further themes from Boardley and Grix (2013. Doping in bodybuilders: A qualitative investigation of facilitative psychosocial processes. Qualitative Research in Sport, Exercise, and Health. Advance online publication, doi 10.1080/2159676X.2013.766809). These analyses evidenced six MD mechanisms, and all three of the themes from Boardley and Grix (2013. Doping in bodybuilders: A qualitative investigation of facilitative psychosocial processes. Qualitative Research in Sport, Exercise, and Health. Advance online publication). Subsequent frequency analyses revealed six of the eight MD mechanisms, and two of the three additional themes, were common across the sample. Overall, the findings suggest MD may help athletes circumvent health- and morality-based deterrents to doping, describe a process linking supplement and PED use and detail how some athletes may actively avoid social censure for doping by only discussing PED use with other PED users from within their training environment.     

Shooting motion in high school,collegiate, and professional men’s lacrosse players

The purposes of this research were to quantify the kinematics of the lacrosse shot, based on arm dominance and player experience level. Male players (N = 39; 14–30 years; high school [n = 24], collegiate [n = 9], professional [n = 6]), performed overhead shots using dominant and non-dominant sides. Motion was captured using a high-speed, 12-camera optical system and high-speed filming. Body segment rotational velocities and joint angles were determined at key points in the shot cycle from foot contact (0% of shot) to ball release (100% of shot). All players shot with less anterior trunk lean, less transverse shoulder rotation, and slower trunk-shoulder rotational velocities with the non-dominant side than the dominant side (all p < 0.05). Professional players produced crosse angular velocities 21% faster than high school or collegiate players (p < 0.05). Transverse shoulder rotation range of motion on both dominant and non-dominant and trunk rotation sides was highest in the professional players (p < 0.05). These kinematic features enable professional players to produce faster ball speeds than younger players (138 ± 7 km/h vs. 112 ± 15 km/h, respectively; p < 0.05). Less anterior lean or suboptimal rotation sequence could increase proximal shoulder forces that could contribute to injury as in other throwing sports.     

Lactate accumulation following isometric exercise training and its relationship with reduced resting blood pressure

The purpose of this study was (a) to assess lactate accumulation during isometric exercise, and to quantify the shifts in accumulation following isometric training; and (b) to relate any training-induced changes in lactate accumulation to reductions in resting blood pressure. Eleven male participants undertook isometric training for a 4-week period using bilateral-leg exercise. Training caused reductions in systolic, diastolic, and mean arterial resting blood pressure (of -4.9 ± 6.3 mmHg, P = 0.01; -2.6 ± 3.0 mmHg, P = 0.01; and -2.6 ± 2.3 mmHg, P = 0.001 respectively; mean ± s). These were accompanied by changes in muscle activity, taken as electromyographic activity to reach a given lactate concentration (from 114 ± 22 to 131 ± 27 mV and from 136 ± 25 to 155 ± 34 mV for 3 and 4 mmol · L(-1) respectively. Training intensity expressed relative to peak lactate was correlated with reduced resting systolic and mean arterial blood pressure. Training caused significant shifts in lactate accumulation, and reductions in resting blood pressure are strongly related to training intensity, when expressed relative to pre-training peak lactate. This suggests that higher levels of local muscle anaerobiosis may promote the training-induced reductions in resting blood pressure.     

Bidirectional cross-sectional and prospective associations between physical activity and body composition in adolescence: birth cohort study

The aim of this study was to investigate the cross-sectional and prospective associations between physical activity and body composition in adolescence. This is a prospective study, including 4,103 adolescents belonging to the Pelotas (Brazil) 1993 birth cohort, who were followed up at the mean ages of 11.3 and 14.7 years. Subsample analyses included 511 individuals with accelerometry and deuterium dilution data at 13.3 years. Sum of skinfolds at age 11.3 years was highly correlated with skinfolds at age 14.7 years (rho = 0.74, P < 0.001). More than 85% of participants remained in the same quintile or changed by not more than one quintile during the 3.4 year period. Tracking of physical activity was considerably lower, although still significant; the correlation was 0.24 (P < 0.001) and 61.4% of the adolescents moved one or less quintiles. In fully-adjusted models, no significant cross-sectional or longitudinal associations were found between physical activity and body composition, neither in boys nor in girls. These null results were confirmed in the 511 individuals with accelerometry and deuterium data. We provide evidence of tracking of physical activity and particularly body composition during adolescence. Our results do not support the hypothesis that physical activity and fatness are strongly related in adolescents.     

Up in the air: Are airlines following the new DOT rules on equal pricing for people with disabilities when websites are inaccessible?

This paper details the findings from a study of airline compliance with Department of Transportation (DOT) regulations requiring that persons with disabilities not be discriminated against in the pricing of airline travel. These regulations mandate that if an airline website is inaccessible for persons with disabilities, the airline must charge the same price that is available on the website and may not charge a fee for purchasing tickets over the phone. To evaluate compliance, the websites of leading airlines were examined for accessibility in terms of the ability to check flight schedules and order tickets. Among the four airlines with barriers to accessibility on their websites, a series of phone calls were made by researchers to assess whether the DOT regulations would be followed. Two of the airlines, USAirways and United, practiced discriminatory pricing, even after being made aware of the regulations, in over one-third of the phone calls. This paper details the findings from the study and analyzes the data in terms of website accessibility, civil rights for travelers with disabilities, and policy implications.     

The Teaching/Learning Relationship in the First Years of School: Some Revolutionary Implications of Vygotskya's Theory

During the last twenty years, Vygotsky's theory has increasingly been cited when considering aspects of early education. Most commonly, however, a single concept (the zone of proximal development) has been used to represent the theory, and treated as synonymous with the view that a teacher's job is to scaffold the children's learning. By contrast, in this paper we stress the fact that Vygotsky's theory is one that requires attending to what individuals bring to interactions, what goes on during those interactions, and the cultural contexts (as they have developed over historical time) of the individuals involved. Equally important, we stress that Vygotsky's view of interactions between teachers and children involves the concept of obuchenie, a Russian term meaning both teaching and learning, rather than scaffolded instruction. To take this position seriously involves making dramatic changes in the process of education as typically practiced. For this reason Vygotsky's theory has revolutionary implications, examples of which we discuss in the final section.