Science and cycling: current knowledge and future directions for research

In this holistic review of cycling science, the objectives are: (1) to identify the various human and environmental factors that influence cycling power output and velocity; (2) to discuss, with the aid of a schematic model, the often complex interrelationships between these factors; and (3) to suggest future directions for research to help clarify how cycling performance can be optimized, given different race disciplines, environments and riders. Most successful cyclists, irrespective of the race discipline, have a high maximal aerobic power output measured from an incremental test, and an ability to work at relatively high power outputs for long periods. The relationship between these characteristics and inherent physiological factors such as muscle capilliarization and muscle fibre type is complicated by inter-individual differences in selecting cadence for different race conditions. More research is needed on high-class professional riders, since they probably represent the pinnacle of natural selection for, and physiological adaptation to, endurance exercise. Recent advances in mathematical modelling and bicycle-mounted strain gauges, which can measure power directly in races, are starting to help unravel the interrelationships between the various resistive forces on the bicycle (e.g. air and rolling resistance, gravity). Interventions on rider position to optimize aerodynamics should also consider the impact on power output of the rider. All-terrain bicycle (ATB) racing is a neglected discipline in terms of the characterization of power outputs in race conditions and the modelling of the effects of the different design of bicycle frame and components on the magnitude of resistive forces. A direct application of mathematical models of cycling velocity has been in identifying optimal pacing strategies for different race conditions. Such data should, nevertheless, be considered alongside physiological optimization of power output in a race. An even distribution of power output is both physiologically and biophysically optimal for longer ( > 4 km) time-trials held in conditions of unvarying wind and gradient. For shorter races (e.g. a 1 km time-trial), an 'all out' effort from the start is advised to 'save' time during the initial phase that contributes most to total race time and to optimize the contribution of kinetic energy to race velocity. From a biophysical standpoint, the optimum pacing strategy for road time-trials may involve increasing power in headwinds and uphill sections and decreasing power in tailwinds and when travelling downhill. More research, using models and direct power measurement, is needed to elucidate fully how much such a pacing strategy might save time in a real race and how much a variable power output can be tolerated by a rider. The cyclist's diet is a multifactorial issue in itself and many researchers have tried to examine aspects of cycling nutrition (e.g. timing, amount, composition) in isolation. Only recently have researchers attempted to analyse interrelationships between dietary factors (e.g. the link between pre-race and in-race dietary effects on performance). The thermal environment is a mediating factor in choice of diet, since there may be competing interests of replacing lost fluid and depleted glycogen during and after a race. Given the prevalence of stage racing in professional cycling, more research into the influence of nutrition on repeated bouts of exercise performance and training is required.     

Technique and timing in women's inward two and one half somersault tuck (405C) and the men's inward two and one half somersault pike (405B) 3 m springboard dives

The purpose of this study was to compare the inward two and one half somersault dive in a tuck position (405C) performed by females (n = 22) and the inward two and one half somersault dive in a pike position (405B) performed by males (n = 24) to determine changes required by females to successfully perform 405B. Key performance variables in inward dives were also compared to those of backward dives. Video data of the dives performed at the 1999 FINA World Diving Cup were captured and digitized to obtain times and postures of the divers at specific events including takeoff and entry. Estimates of flight height and mass-normalised work done on the springboard were obtained from flight times. Some females worked the springboard strongly enough to generate sufficient height and rotation to perform 405B. Males performed 405B comfortably because they achieved better height and rotation than the females. A comparison of backward and inward dives revealed that divers are able to attain greater height in backward dives than inward dives.     

The motor core of speech: a comparison of serial organization patterns in infants and languages

Comparison of serial organization of infant babbling and early speech with that of 10 languages reveals four movement-related design features reflecting a deep evolutionary heritage: (1) the cyclical consonant-vowel alternation underlying the syllable, a "Frame" for speech consisting of mandibular oscillation, possibly evolving from ingestive cyclicities (e.g., chewing) via visuofacial communicative cyclicities (e.g., lipsmacks); (2) three intracyclical consonant-vowel co-occurrence preferences reflecting basic biomechanical constraints-coronal consonants-front vowels, dorsal consonants-back vowels, and labial consonants-central vowels; (3) a developmental progression from above-chance to below-chance levels of intercyclical consonant repetition; (4) an ease-related labial consonant-vowel-coronal consonant sequence preference for word initiation. These design features presumably result from self-organizational responses to selection pressures, primarily determined by motor factors. No explanation for these design features is available from Universal Grammar, and, except for feature 3, perceptual-motor learning seems to have only a limited causal role in acquisition of any design feature.     

Leisure time physical activity in Australian women: relationship with well being and symptoms

This paper explores the association between moderate levels of physical activity (PA) and health benefits in well being and symptoms such as tiredness, back pain, and constipation. Participants in the Australian Longitudinal Study on Women's Health, 14,502 young women (ages 18-23 years), 13,609 middle-age women (45-50 years), and 11,421 older women (ages 70-75 years), answered questions about vigorous and less vigorous exercise (used to determine a physical activity score), well being (SF-36), symptoms, and medical conditions. There were significant associations between the PA score and SF-36 in each cohort. Odds ratios (OR) for a range of symptoms and conditions were lower for women who reported low to moderate activity than for sedentary women, for example, for young women or for constipation = 0.76 (CI, 0.65-0.89), for middle-age women or for tiredness = 0.70 (0.63-0.78). There was no threshold of PA at which health benefits increased significantly. Although cross-sectional, the findings suggest that low-to-moderate levels of exercise are associated with a range of health benefits for women of all ages. These preliminary findings will be followed up during the longitudinal study.     

影响青少年长跑运动员训练的一些因素

青少年长跑运动员的训练尽管与成人的训练有些基本的相同点,但在其准备阶段还有些需要考虑的因素。这些特定的因素中最重要的有以下几条。——考虑特定的年龄特点。——采用均衡提高休能的原则。——使用的训练方法和手段能为将来取得最