How to Get Used to University Life

Liu Bin刚刚跨入了大学校门。大学里的生活自由灵活。比起高中备受约束的日子可谓天壤之别,可这没有老师“管教”的生活。Liubjn反而有点不适应了。如何安排好自己的大学生活？Brad又会有哪些建议？     

A protocol for measuring the direct effect of cycling on neuromuscular control of running in triathletes

Abstract

The direct effects of cycling on movement and muscle recruitment patterns (neuromuscular control) during running are unknown but critical to success in triathlon. We outline and test a new protocol for investigating the direct influence of cycling on neuromuscular control during running. Leg movement (three-dimensional kinematics) and muscle recruitment (surface electromyography, EMG) were compared between a control run (no prior exercise) and a 30-min transition run that was preceded by 20 min of cycling. We conducted three experiments investigating: (a) the repeatability (between-day reliability) of the protocol; (b) the ability of the protocol to investigate, in highly trained national or international triathletes, the direct influence of cycling on neuromuscular control during running independent of neuromuscular fatigue; and (c) the ability of the protocol to provide a control, or baseline, measure of neuromuscular control (determined using a measure of stability) without causing fatigue. Kinematic and EMG measures of neuromuscular control during running showed moderate to high repeatability: mean coefficients of multiple correlation for repeatability of EMG and kinematics were 0.816 ± 0.014 and 0.911 ± 0.031, respectively. The protocol provided a robust baseline measure of neuromuscular control during running without causing neuromuscular fatigue (coefficients of multiple correlation for stability of EMG and kinematics were 0.827 ± 0.023 and 0.862 ± 0.054), while EMG and force data provided no evidence of fatigue. The protocol outlined here is repeatable and can be used to measure any direct influence of cycling on neuromuscular control during running.     

Age-Related Differences in Muscular Strength and Muscular Endurance among Female Masters Swimmers

Abstract

The purpose of this study was to examine age-related differences in muscular strength and muscular endurance among 73 female masters swimmers aged 24 to 71 years. Each subject was assessed on measures of body size, grip strength, peak isokinetic torque of shoulder and knee flexion and extension, and endurance of shoulder and knee movements. Although swim training appears to have resulted in higher strength values for these swimmers than for less active women, an age-related decline in muscular strength values was nevertheless apparent. The results fail to reveal a similar age-related trend for muscular endurance, suggesting that swim training influences muscular endurance more than muscular strength among adult women.     

Influence of Motor and Sensory Sets on Reaction Latency and Speed of Discrete Movements

Abstract

College men and women were tested as to reaction time and speed of an arm movement using both motor-oriented and stimulus-oriented set. The results confirmed a hypothesis based on neuromotor coordination theory that predicted slower movement and greater reaction latency when the motor set was used. However, the 20 percent of subjects who had a natural motor set tendency moved faster with an enforced motor set than with an enforced sensory set. The conditions of enforced set caused a moderate positive correlation between reaction and movement times. Women subjects reacted and moved slower than men, but were similarly influenced by the two enforced set conditions. Their natural set tendency was definitely stimulus-oriented, while men tended to have a neutral orientation.     

Effects of Ventilation on Segmental Bioimpedance Spectroscopy Measures Using Generalizability Theory

The purpose of this study was to examine the effect of three ventilation conditions (i.e., normal, regimented, and no-ventilation) on the reproducibility of bioimpedance scores in humans for the forearm and trunk segments. One hundred able-bodied North American men and women, from 18 to 71 years of age, volunteered as participants. The experimenters used a Xitron Bio-Impedance Analyzer System model 4200 instrument with Hydra software (Xitron Technologies, San Diego, California, USA) to collect bioimpedance data on extracellular fluid and intracellular fluid scores. The experimenters analyzed the data using the generalizability theory,with persons as the facet of differentiation and time as the facet of generalization. The major findings were (a) ventilation conditions did not have a significant impact on the reproducibility of the test scores, (b) the forearm segment produced consistently higher intracellular fluid generalizability coefficients across three ventilation conditions for both gender groups when compared to the trunk segment, (c) the trunk segment produced intracellular fluid generalizability coefficients that were higher for the male group, and (d) the measurement error affected extracellular fluid scores less than segmental intracellular fluid scores.     

Establishing the Test–Retest Reliability & Concurrent Validity for the Repeat Ice Skating Test (RIST) in Adolescent Male Ice Hockey Players

In this study the authors examine the test–retest reliability and concurrent validity of the Repeat Ice Skating Test (RIST). This was an on-ice field anaerobic test that measured average peak power and was validated with 3 anaerobic lab tests: (a) vertical jump, (b) the Margaria–Kalamen stair test, and (c) the Wingate Anaerobic Test. The participants (n?=?14) were 11- to 12-year-old males selected from a Peewee “A” level ice hockey team (Thunder Bay, Canada). The results of the test–retest reliability estimation showed that the RIST was a reliable test at measuring average peak power in watts (R = .99, C.I._95% = 0.97 to 0.99) and watts per kilogram (R = .98, C.I._95% = 0.94 to 0.99). The RIST was also a valid test when correlated with the 3 anaerobic lab tests for measuring peak power in watts: vertical jump (r = .86, C.I._95% = 0.72 to 0.94), Margaria–Kalamen stair test (r = .66, C.I._95% = 0.39 to 0.83) and Wingate Anaerobic Test (r = .86, C.I._95% = 0.72 to 0.93). The test is considered promising because it does not require any specific equipment, and is a sport-specific, on-ice test, that can be administered during a regular ice hockey practice session.     

Child, Program, and Family Ecological Variables in Early Intervention

This study is based on a conceptual framework which emphasized the importance of viewing early intervention outcomes in relation to both program and nonprogram variables. Three broad classes of independent variables were included in the framework child, program, and family ecology. The unique and combined contributions of these three sets of variables to the prediction of three indices of intervention outcome was assessed through regression techniques. As much as 68% of the variance in children's post-intervention developmental age (DA2) was explained by the combined influence of all three classes of variables. All three classes of variables again contributed uniquely to the prediction of parental satisfaction with the intervention, explaining 45% of the variance. The three classes of variables explained 36% of the variance in children's rate of development during the intervention (RDI), although the contribution of the program class was very minimal. In addition to ascertaining the contributions of sets of variables, the importance of individual variables within sets was also examined. Results from both types of analysis underscored the important role of nonprogram variables in the determination of both child and parental outcomes. The implications of these findings for the design and evaluation of early intervention are discussed.     

A comparison of the Rescorla-Wagner and Pearce models in a negative patterning and a summation problem

In two experiments, we examined two related conditioning problems previously investigated by Red-head and Pearce (1995a) and Pearce, Aydin, and Redhead (1997). Experiment 1 involved an A+, B+, C+, AB+, AC+, BC+, ABC2 discrimination. The Rescorla-Wagner model predicts that response to AB, AC, and BC will be greater than that to A, B, and C at asymptote, whereas the Pearce model makes the opposite prediction. In Experiment 2, we investigated the responding to a novel ABC compound in groups trained with either A+, B+, C+ or AB+, AC+, BC+. The Rescorla-Wagner model predicts greater response to ABC in the group trained with A+, B+, C+ than in the group trained with AB+, AC+, BC+, whereas the Pearce model makes the opposite prediction. In contrast to the findings of Redhead and Pearce (1995a) and Pearce et al. (1997) in pigeon autoshaping, our findings in rabbit eyelid conditioning support the Rescorla-Wagner model.