Book reviews

Clinical sports medicine, Robert C. Cantu, (ed.), The Collamore Press, Lexington, Massachusetts, Toronto, 1984. 219 pp, £19.95 (hb), ISBN 0 669 06842 X

Sports injuries, a self‐help guide, Vivian Grisogono, John Murray Ltd, London, 1984. 293 pp, £7.95 (hb), ISBN 0 7195 4111 5

Athletes’ guide to mental training, Robert N. Nideffer, Human Kinetics, Champaign, Illinois (distributed in the UK by Eddington Hook & Co.) 1985. vii +156 pp, $9.95 (pb), ISBN 0 931250 96 X

Scientific foundations of coaching, R.R. Pate, B. McClenaghan and R. Rotella, Saunders College Publishing, Philadelphia, 1984. xii + 344 pp, £21.95(hb), ISBN 0 03 057961 9

Mathematics in sport, M. Stewart Townend, Ellis Horwood, Chichester, 1984. 202 pp (hb), ISBN 0 85312 717 4

Frontiers of exercise biology, ’Big Ten Body of Knowledge’ symposium series, Vol. 13 K.T. Borer, D.W. Edington and T.P. White (eds), Human Kinetics Publishers Inc., Champaign, Illinois, (distributed in the UK by Edington Hook & Co.), 1983. vii + 295 pp, $31.95(hb), ISBN 0 931250 49 8

The knee, Philippe Segal and Marcel Jacob, Wolfe Medical Publications, Frome, Somerset, 1984. 143 pp (hb), £15, ISBN 2 224 00887 2

Psychological foundations of sport, J.M. Silva and R.S. Weinberg (eds), Human Kinetics, Champaign, Illinois, (distributed in the UK by Eddington Hook & Co), 1984. xxiv + 528 pp, £22.50 (hb), ISBN 0 93 1250 59 5

Physical activity and the social sciences, W. Neil Widmeyer, Mouvement Publications Inc., Ithaca, 1983. 472 pp, £9.00 (pb), ISBN 0 932392 13 X     

The menstrual cycle and its effect on the immune status of female endurance runners

Twenty highly trained, eumenorrhoeic female endurance runners were studied over three consecutive menstrual cycles. Average training distance per week, total years training and mood states were recorded throughout the three cycles. Salivary progesterone and menstrual cycle diaries were recorded over the first two cycles to identify luteal phase onset and the presence of any menstrual irregularities. Saliva samples were collected daily over the third cycle for analysis of immunoglobulin A (IgA) concentration and secretion and saliva flow rate. Twoway analysis of variance (ANOVA) revealed no significant differences in mood states across the phases of the menstrual cycle ( P > 0.05). Training logs indicated that training did not alter throughout the 3 month study. One-way ANOVArevealed no significant differences in IgA concentration ( P = 0.92), secretion rate ( P = 0.84) or saliva flow rate ( P = 0.95) across the phases of the menstrual cycle. Pearson's product-moment correlation revealed no relationship between IgA concentration and progesterone between the phases of the cycle ( r = 0.39). We conclude that, in ovulatory female endurance runners whose physical and emotional stress are stable, IgA concentration is not significantly affected by fluctuations in progesterone during the menstrual cycle.     

BASES Position Statement on Guidelines for Resistance Exercise in Young People

Abstract

Despite the performance concerns of dehydration in other sports, there are currently no data on the effects of rapid weight-loss on the physical and cognitive performance of jockeys in a sport-specific context. In a randomised crossover design, eight Great Britain (GB) male licensed jockeys were assessed for chest strength, leg strength, simulated riding performance (assessed by maximum pushing frequency on a mechanical riding simulator during the final two furlongs of a simulated 2 mile race) and simple reaction time after performing 45 min of exercise, during which euhydration was maintained (Control trial) or induced 2% dehydration (Rapid Weight-Loss trial). Reductions in both chest (–13.8 ± 3.03% vs. 0.62 ± 1.04%) and leg strength (–4.8 ± 4.8% vs. –0.56 ± 2.5%) were greater in Rapid Weight-Loss compared with Control (P < 0.01 and P = 0.04, respectively). Similarly, reductions in simulated riding performance were also greater (P = 0.05) in Rapid Weight-Loss (–2.8 ± 4.0%) compared with Control (–0.07 ± 1.5%), whereas there were no significant changes (P = 0.14) in simple reaction time. We conclude that a 2% reduction in body mass, as achieved by 45 min of moderate-intensity exercise undertaken in a sweatsuit (a common method of inducing acute dehydration by jockeys), significantly impairs maximum pushing frequency during a simulated race. In addition, the observed reductions in strength may also increase the occupational hazards associated with race riding.     

Embedding with multiple knowledge sources to improve innovation performance: the learning experience of Motorola in Brazil

This article explores how a subsidiary of a multi-national enterprise (MNE) in an emerging economy embeds with multiple knowledge sources, both in its corporate network (internal) and in the host country (external), to create the capability to undertake innovative activities. Drawing on first-hand and intra-firm field evidence over the lifetime of a subsidiary in the information and communications technology industry in Brazil (1996–2009) the article finds that: (1) Within 10 years, the case subsidiary attained advanced, near-world leading innovation performance in three technological functions: project management, software engineering and product and solutions; (2) This was an outcome of how the firm simultaneously engaged in knowledge-intensive linkages based on increased frequency of use and improved quality over time, with specific internal and external counterparts; (3) However, some counterparts and linkages were more effective than others in contributing to the subsidiary's innovation performance. Drawing on a novel approach that examines the relationship between dual embeddedness and innovative performance, this article extends our understanding of embeddedness as part of knowledge-seeking strategies of MNE-subsidiaries. It also provides new insights to deepen the analysis of the nuances of subsidiaries’ multiple embeddedness, especially in emerging economies.     

从墨家和平思想看中国和平发展战略的思想渊源与现代重构

中国和平发展战略思想是墨家及中国传统思想家朴素的和平思想的现代转型与重构,是马克思主义和平发展思想在当代的继承与发展.探究梳理墨家及中国传统文化中的和平思想精髓,对于继承和弘扬马克思主义和平发展思想精华,把握中国和平发展战略思想的意蕴要旨具有重要意义.     

Relationships between cardiorespiratory fitness,inhibition, and math fluency: A cluster analysis

ABSTRACT

This study identified clusters of adolescents who share similar cardiorespiratory fitness levels and analysed the relationships between cardiorespiratory fitness, inhibition, and math fluency in each of the clusters. The subjects were 490 high-school students aged 10–16 years. The mean age was 13.82 years (SD = 1.12). Latent class analysis identified three clusters with high, medium, and low levels of cardiorespiratory fitness. The high-fitness cluster achieved higher scores in inhibition and math fluency than the low-fitness cluster. Path analysis revealed that the influence of cardiorespiratory fitness on inhibition was non-existent in the three clusters. The effect of inhibition on math fluency was positive and significant in all three cardiorespiratory fitness levels. Cardiorespiratory fitness had a direct, positive, and significant effect on math fluency only in the high-fitness cluster. Therefore, a high level of cardiorespiratory fitness is a significant determining factor in the explanation of math fluency. These results indicate that inhibition does not mediate the relationship between cardiorespiratory fitness and math fluency. However, the benefits of cardiorespiratory fitness affect math fluency, which has important implications for the educational environment and the teaching/learning process.     

Comment on ‘Ventilation and blood lactate increase exponentially during incremental exercise’ : A reply

Oar force and oar angle data resulting from a 6‐min maximal rowing ergometer test undertaken by novice (n = 9), good (n ‐ 23) and national (n = 9) level male rowers, were used to identify biomechanical performance variables which accurately discriminated between rowers of differing ability levels. The variables included two work capacity measures, mean propulsive power output per kilogram of body mass (W kg^‐1) and propulsive work consistency (%), and two skill variables, stroke‐to‐stroke consistency (%) and stroke smoothness (%). Discriminant function analysis indicated the presence of two functions, both of which clearly indicated the importance of mean propulsive power output per kilogram of body mass as a discriminating variable. Function 2 gave greater weight to stroke‐to‐stroke consistency and stroke smoothness than function 1; however, function 1 was the most powerful discriminator. Classification procedures were used to predict the ability level to which a rower most likely belonged and involved defining the ‘distance’ between each rower and each ability level centroid, with the rower being classified into the ‘nearest’ ability level. These procedures indicated that 100% of the elite, 73.9% of the good, 88.9% of the novice and 82.9% of all rowers were correctly classified into their respective skill levels. Stepwise discriminant analysis included the variables in the following order: mean propulsive power output per kilogram of body mass, stroke‐to‐stroke consistency, stroke smoothness and propulsive work consistency (P < 0.001). The results of this study indicate that biomechanical performance variables related to rowing capacity and skill may be identified and used to discriminate accurately between rowers of differing skill levels, and that, of these variables, propulsive work consistency is the least effective discriminator.     

Age,Physical Activity,Physical Fitness,Body Composition,and Incidence of Orthopedic Problems

Abstract

The incidence of orthopedic problems was examined in 5, 582 men and women who attended the Cooper Clinic in Dallas, Texas between 1974 and 1982. The effects of age, physical activity, physical fitness, and body mass index (EMI) on the occurrence of these problems were examined using a proportional hazards approach. The expected risk of orthopedic problems per person-year was 0.045 for men and 0.046 for women. For men, physical fitness, BMI, and physical activity were associated with orthopedic problems, while for women, physical activity was the main predictor. Age was not a factor for either gender. The effect of change in physical fitness, physical activity, and BMI was examined in a subset of 2, 325 persons with more than one visit to the clinic. For women, physical activity and a decrease in BMI were associated with orthopedic problems, while for men none of those factors were significant. Again, age was not a factor in either group. The absence of any age effect on the occurrence of problems suggests that with regard to orthopedic problems, moderate amounts of physical activity in generally healthy persons may be recommended without special consideration as to age.     

Lactate and Phosphagen Levels in Muscle Immediately after a Maximum 300 m Run at Sea Level

Abstract

The relative effectiveness of six intensive training programs on the development of four selected skills was studied, with emphasis on limited time encountered within the semester organizational plan. One hundred and twenty college freshmen men volunteers were randomly assigned to training groups of 30 members each, which met for two sessions a week for 16 weeks.

Results indicated that: (a) direct practice jumping, alone or combined with repetitive sprinting or weight training, was significantly superior to weight training alone on standing broad jump development; (b) direct practice of a zigzag run was superior to both weight training and repetitive sprinting; and (c) when group acquisition of “adequate” skill is the objective, performance improvements educed over the first nine weeks were great enough to question the merits of persisting at an activity over a full semester. Only the zigzag run was adversely affected by the spring vacation cessation of training.     

Individual t Tests versus Multiple Range Tests

Abstract

In an effort to determine the better method of starting and running to the right, two methods, the jab step and the cross-over step, were compared. Thirty male students, 13–17 years old, were timed at four testing stations, 5, 11, 22, and 37 feet from the start. Reliabilities were very high. Analysis of variance revealed the cross-over step to be significantly faster than the jab step at each timing station.