Rhythmic Isometric Fatigue Patterns of the Elbow Flexors and Knee Extensors

Abstract

Twenty-seven male subjects performed two 5-min bouts of rhythmic, isometric elbow flexion and two similar bouts of knee extension at a rate of 30 maximal contractions per min. Exponential analyses revealed that the pattern of fatigue for each limb followed a single component curve of the form: Y_t = a₀e ^?Kot + c. An analysis of variance comparing the results from the two limbs revealed that (a) the strength scores for the leg were significantly (p < .05) higher than those for the arm throughout the exercise bouts; (b) both limbs experienced a significant strength decrement; and (c) there was significant interaction between trials and limbs. It appeared that the greater loss of strength by the knee extensors was reponsible for this interaction. It was concluded that during a rhythmic, all-out task, the rates of fatigue experienced by the two muscle groups tend to differ, with the elbow flexors fatiguing more rapidly initially but reaching a plateau at a relatively higher level than the knee extensors.     

Athletics

The purposes of this study were to investigate (1) the relationships between official distance and selected ground reaction measures during discus throwing; and (2) the relationships between selected ground reactions and selected lower extremity joint kinetics. Three high‐speed video cameras and three force plates were used to collect three‐dimensional videographic and force plate data in this study. An inverse dynamic model was used to determine the lower extremity kinetics. Multiple regression analyses were conducted to determine relationships of the selected kinematic and kinetic measures with the official distance. Official distance was significantly correlated with ground reaction forces on the left foot during the first single‐support phase, on the right foot during the second single‐support phase and delivery phase, and on the left foot during the delivery phase. Also, the right‐hip extension and internal rotation moments and left‐knee extension moment during the delivery phase were significantly correlated with official distance. These results suggest that discus throwers should drive vigorously forward during the first single‐support phase and increase the landing impact force on the right foot after flight. Also they should increase forward and rightward ground reaction force on the right foot and backward and vertical force on the left foot by powerful right‐hip extension and internal rotation and left‐knee extension during the delivery phase. These results provide critical information regarding the training of discus‐throwing techniques, and the direction of future biomechanical studies on this event.     

Multi-postpath-based lookahead multiconstraint QoS routing

Multiconstraint QoS (quality of service) routing is an essential mechanism for QoS-guaranteed services. Unfortunately, the multiconstraint QoS routing problem is NP-complete. In this paper, we propose a heuristic multiconstraint QoS routing scheme, MPLMR (multi-postpath-based lookahead multiconstraint routing). MPLMR is a routing scheme using an extended shortest-path algorithm. As in previous schemes such as TAMCRA and H_MCOP, MPLMR stores a limited number of subpaths between the source node and each intermediate node, and extends these subpaths toward the destination node. However, MPLMR uses an improved “lookahead” method to estimate the path length of the full path to which each subpath is extended. MPLMR then selects and stores the subpaths that have higher likelihood than other subpaths to be extended to feasible paths. We show via simulation that MPLMR has a smaller probability of missing a feasible path than competing schemes in the literature.     

THE EMERGENCE OF COMMUNICATION STUDIES

This article charts the vast multiplicity of phenomena that can be brought under the ‘communication’ umbrella. The author denies that these can be integrated within a framework of communication regarded as a discipline in its own right. He then considers successively the possibility of tackling communication from the perspective of some single established discipline (sociology, political science, etc.) and that of treating it as the meeting ground of several disciplines. Criteria for designing multi‐disciplinary courses are advanced and illustrated in the mass communication field. Finally, a number of structurally based obstacles to further progress are identified in the lack of effective linkages between the chief sectors concerned with communication study ‐‐ researchers, teachers and media professionals.     

Learning Disabilities in Taiwan: A Case of Cultural Constraints on the Education of Students with Disabilities

Learning disabilities (LD) has been recognized as a category of special education in Taiwanese law since 1984, and policies ensure educational services for children and youth who have LD. The official definition and identification criteria established in Taiwan's laws closely correspond with those of the United States, but practice differs, largely influenced by the people's cultural and linguistic background. I discuss these legal and cultural features as well as other matters (e.g., growth and change in professional literature on LD). Compared to economically developed countries such as the United States, the educators in Taiwan implement identification procedures, placement, and services at a lower cost. Contents of implementation are introduced in detail. The prevalence rate of LD has been very low (<1 percent). I examine culture‐ and/or society‐specific reasons for low prevalence, such as Chinese orthography, regular teachers' compliance with referral procedures, the education‐first belief of parents, and problems with identification procedures.     

Innovation in postgraduate teaching: mixed methods to enhance learning and learning about learning

Growing pressure to restructure and reform tertiary education is encouraging university academics to use innovative practices that assist students to develop ‘employable’ skills. The hybrid approach described in this paper stimulated students to be self‐directed adult learners who maximized their learning of content and skills by means of problem‐based learning and action research strategies. The lecturer also operated as a reflective practitioner and role model by using an action research approach. This paper demonstrates the value of student empowerment, communication and leadership in autonomous learning groups. It outlines methods by which academic teaching staff can build continuous improvement into a university unit’s curriculum design and processes. These can be powerful additions to lecturers’ teaching strategies and to students’ learning experiences.