Carbohydrate intake and training efficacy – a randomized cross-over study

Carbohydrate (CHO) availability during endurance exercise seems to attenuate exercise-induced perturbations of cellular homeostasis and might consequently diminish the stimulus for training adaptation. Therefore, a negative effect of CHO intake on endurance training efficacy seems plausible. This study aimed to test the influence of carbohydrate intake on the efficacy of an endurance training program on previously untrained healthy adults. A randomized cross-over trial (8-week wash-out period) was conducted in 23 men and women with two 8-week training periods (with vs. without intake of 50g glucose before each training bout). Training intervention consisted of 4x45 min running/walking sessions/week at 70% of heart rate reserve. Exhaustive, ramp-shaped exercise tests with gas exchange measurements were conducted before and after each training period. Outcome measures were maximum oxygen uptake (VO_2max) and ventilatory anaerobic threshold (VT). VO_2max and VT increased after training regardless of CHO intake (VO_2max: Non-CHO 2.6 ± 3.0 ml*min^?1*kg^?1 p = 0.004; CHO 1.4 ± 2.5 ml*min^?1*kg^?1 p = 0.049; VT: Non-CHO 4.2 ± 4.2 ml*min^?1*kg^?1 p < 0.001; CHO 3.0 ± 4.2 ml*min^?1*kg^?1 p = 0.003). The 95% confidence interval (CI) for the difference between conditions was between +0.1 and +2.1 ml*min^?1*kg^?1 for VO_2max and between ?1.2 and +3.1 for VT. It is concluded that carbohydrate intake could potentially impair the efficacy of an endurance training program.     

Adapting,correcting and sequencing movements: does working-memory capacity play a role?

Interest in the role of working-memory capacity in everyday abilities has recently extended to the acquisition of motor skills. This review article examines the role of working-memory capacity in two areas of motor skill acquisition: (1) adapting and correcting movements in response to errors, and (2) sequencing movement patterns. Across a number of studies it was evident that individuals with low or underdeveloped working-memory capacity experienced diminished learning when the practice contexts placed high demands on working memory. Verbal working-memory capacity was associated with the ability to correct movement errors, while several studies revealed the importance of spatial abilities, including spatial working-memory capacity, when learning movement adaptations. Visuo-spatial working-memory capacity correlated with movement sequence learning, either explicitly or implicitly, but old age affected this relationship. Despite these correlations, however, our understanding of the relationship between working-memory capacity and motor skill acquisition is clouded by inconsistent results and a reliance on correlational analyses. To extend understanding of the role of working-memory capacity in motor skill acquisition, researchers should seek to explore novel experimental paradigms that bear closer resemblance to everyday tasks.     

Virtual Knowledge‐Sharing Communities of Practice at Caterpillar: Success Factors and Barriers

This article reports the results of a qualitative study of success factors and barriers to the development of virtual knowledge‐sharing communities of practice at Caterpillar Inc., a Fortune 100 multinational corporation. The study identified several prerequisites for successful knowledge management through virtual communities of practice: knowledge sharing as a key element of the corporate culture; employees regarding knowledge as a public good belonging to the whole organization, and not as their individual asset; communities self‐organizing around specific performance‐related problems or areas of professional interest of their members; and communities supported by volunteer managers and active core groups of experts. At the same time, the study has identified a number of important barriers to virtual community development. Specifically, even when employees give the highest priority to the interests of the organization, they tend to shy away from contributing knowledge for a variety of other reasons not related to information hoarding. In addition, corporate security considerations and concerns about the accuracy of the information and the potential information overload could clash with the need to promote spontaneous generation of information. Suggestions for overcoming the identified barriers, future research directions, and implications for HRD professionals are formulated.