Bicycling

In the contemporary American urban renaissance, formerly fringe efforts to produce place, conducted by longtime residents and “urban pioneers” alike, now shape mainstream urbanism. Gardening and bicycling are constitutive of contemporary excitement about the city, representing the reinvigoration of the urban neighborhood following the depredations of suburbanization. This paper draws on research in California cities to offer a sympathetic critique of these leading edges of progressive urbanism, arguing that advocates’ overwhelming focus on the local creates a scalar mismatch between the horizon of political action and the problems they hope to address. Even as supporters of gardening and cycling understand themselves as implicitly allied with struggles for the right to the city, their work to produce local space is often blind to, and even complicit in, racialized dynamics of accumulation and exclusion that organize metropolises. The result is a progressive urbanism largely disconnected from broader left struggles for spatial justice.

Purpose: This study investigated the satisfaction of elite female cyclists with their body weight (BW) in the context of race performance, the magnitude of BW manipulation and the association of these variables with menstrual function. Methods: Female competitors in the Australian National Road Cycling Championships (n=32) and the Oceania Championships (n=5) completed a questionnaire to identify current BW, BW fluctuations, perceived ideal BW for performance, frequency of weight consciousness, weight loss techniques used, and menstrual regularity. Results: All but one cyclist reported that female cyclists are 'a weight conscious population' and 54% reported having a desire to change BW at least once weekly.

We compared the effect of glycerol-induced hyperhydration (GIH) to that of water-induced hyperhydration (WIH) on cardiovascular and thermoregulatory functions and endurance performance (EP) during prolonged cycling in a temperate climate in subjects consuming fluid during exercise. At weekly intervals, 6 trained male subjects ingested, in a randomized, double-blind, counterbalanced fashion, either a glycerol (1.2 g glycerol/kg bodyweight (BW) with 26 mL/kg BW of water - aspartame-flavored fluid) or placebo solution (water - aspartame-flavored fluid only) over a 2 h period. Subjects then performed 2 h of cycling at 66% of the maximal oxygen consumption (VO2 max) and 25 °C while drinking 500 mL/h of sports drink, which was followed by a step-incremented cycling test to exhaustion. Levels of hyperhydration did not differ significantly between treatments before exercise. During exercise, GIH significantly reduced urine production by 246 mL. GIH did not increase sweat rate nor did it dec...

Strategies applied during sleep to potentially enhance athlete performance use different atmospheric conditions. High altitude conditions are known to affect sleep adversely but the effects of mild-moderate altitude and 02 enrichment at mild altitude are uncertain. We performed case studies using two elite female road cyclists (mass and maximal aerobic power of 62 kg, 65.8 ml.kg-l.min-1; 57 kg, 62.7 ml.kg ~1 °min-1) to examine changes in sleep for different atmospheric conditions applied throughout the preparation for, and during, an International Stage race. Conditions were: i} normoxia (600 m), ii} simulated moderate altitude (2650 m), iii) natural mild altitude (1380 m) and iv} 02 enrichment at mild altitude (30% 02@ 1300-1500 m). We measured respiratory disturbances, arousals, number of awakenings, blood oxygen saturation (Sp02), heart rate (HR), rapid eye movement sleep (REM) and deep sleep. Respiratory disturbances, SpO 2 and HR responses were similar for both cyclists for all conditions. Compared with normoxia, both cyclists had somewhat reduced REM at natural mild altitude and moderate simulated altitude but differed in their REM and deep sleep responses to 02 enrichment. Compared with mild altitude, both showed increased awakenings and deep sleep with 02 enrichment. Only one cyclist clearly increased her REM sleep with 02 enrichment compared to mild altitude. Our data highlight two different sleep quality responses to atmospheric variation.

Cycling is the most energy-efficient mode of transport and can bring extensive environmental, social and economic benefits. Research has highlighted negative perceptions of safety as a major barrier to the growth of cycling. Understanding these perceptions through the application of novel place-sensitive methodological tools such as mental mapping could inform measures to increase cyclist numbers and consequently improve cyclist safety. Key steps to achieving this include a) the design of infrastructure to reduce actual risks and b) targeted work on improving safety perceptions among current and future cyclists. This study combines mental mapping, a stated-preference survey and a transport infrastructure inventory to unpack perceptions of cycling risk and to reveal both overlaps and discrepancies between perceived and actual characteristics of the physical environment. Participants translate mentally mapped cycle routes onto hardcopy base-maps, colour-coding road sections according to risk, while a transport infrastructure inventory captures the objective cycling environment. These qualitative and quantitative data are matched using Geographic Information Systems and exported to statistical analysis software to model the individual and (infra)structural determinants of perceived cycling risk. This method was applied to cycling conditions in Galway City (Ireland). Participants' (n=104) mental maps delivered data-rich perceived safety observations (n=484) and initial comparison with locations of cycling collisions suggests some alignment between perception and reality, particularly relating to danger at roundabouts. Attributing individual and (infra)structural characteristics to each observation, a Generalized Linear Mixed Model statistical analysis identified segregated infrastructure, road width, the number of vehicles as well as gender and 2 cycling experience as significant, and interactions were found between individual and infrastructural variables. The paper concludes that mental mapping is a highly useful tool for assessing perceptions of cycling risk with a strong visual aspect and significant potential for public participation. This distinguishes it from more traditional cycling safety assessment tools that focus solely on the technical assessment of cycling infrastructure. Further development of online mapping tools is recommended as part of bicycle suitability measures to engage cyclists and the general public and to inform 'soft' and 'hard' cycling policy responses.

Eight Italian hospital or University gynecology clinics participated in a prospective survey of patients with culture-confirmed symptomatic vulvovaginal candidiasis (VVC) (October 1999 to March 2001). Of 1138 patients recruited in the study, 931 were evaluable. A recent history of VVC was documented in 43.5% patients (358/823) with a mean number of 2.9±2.7 episodes per patient (N=302). A total of 77

The purpose of this study was to determine the efficacy of rate of perceived exertion (RPE) to monitor exercise intensity in older adults. Middle-aged (46.9 +/- 7.0 years, n = 24) and older women (75.5 +/- 3.8 years, n = 29) performed a graded maximal exercise test on a cycle ergometer while RPE, oxygen uptake, heart rate, and blood lactate levels were measured. The Pearson's product moment correlation coefficient between RPE and oxygen uptake for each stage of the graded exercise test was calculated for each participant. The mean coefficient for the older group (r =.954) was similar to that of middle-aged group (r =.963). The autocorrelation coefficient was much lower (r =.411) in the older group than in the middle-aged group (r =.871). Variability in RPE through the graded exercise test was similar between the two groups. In conclusion, RPE was strongly associated with oxygen uptake in the older group. These results indicate that RPE is effective in monitoring exercise intensi...

Given the important role of the brain in regulating endurance performance, this comparative study sought to determine whether professional road cyclists have superior inhibitory control and resistance to mental fatigue compared to recreational road cyclists. After preliminary testing and familiarization, eleven professional and nine recreational road cyclists visited the lab on two occasions to complete a modified incongruent colour-word Stroop task (a cognitive task requiring inhibitory control) for 30 min (mental exertion condition), or an easy cognitive task for 10 min (control condition) in a randomized, counterbalanced cross-over order. After each cognitive task, participants completed a 20-min time trial on a cycle ergometer. During the time trial, heart rate, blood lactate concentration, and rating of perceived exertion (RPE) were recorded. The professional cyclists completed more correct responses during the Stroop task than the recreational cyclists (705±68 vs 576±74, p = 0...

Cycling is the most energy-efficient mode of transport and can bring extensive environmental, social and economic benefits. Research has highlighted negative perceptions of safety as a major barrier to the growth of cycling. Understanding these perceptions through the application of novel place-sensitive methodological tools such as mental mapping could inform measures to increase cyclist numbers and consequently improve cyclist safety. Key steps to achieving this include: (a) the design of infrastructure to reduce actual risks and (b) targeted work on improving safety perceptions among current and future cyclists. This study combines mental mapping, a stated-preference survey and a transport infrastructure inventory to unpack perceptions of cycling risk and to reveal both overlaps and discrepancies between perceived and actual characteristics of the physical environment. Participants translate mentally mapped cycle routes onto hard-copy base-maps, colour-coding road sections accord...

Objective: The usefulness of massage as a recovery method after high-intensity exercise has yet to be established. We aimed to investigate the effects of whole-body massage on heart rate variability (HRV) and blood pressure (BP) after repeated high-intensity cycling exercise under controlled and standardized pretest conditions. Methods: The study included 62 healthy active individuals. After baseline measurements, the subjects performed standardized warm-up exercises followed by three 30-second Wingate tests. After completing the exercise protocol, the subjects were randomly assigned to a massage (myofascial release) or placebo (sham treatment with disconnected ultrasound and magnetotherapy equipment) group for a 40-minute recovery period. Holter recording and BP measurements were taken after exercise protocol and after the intervention. Results: After the exercise protocol, both groups showed a significant decrease in normal-to-normal interval, HRV index, diastolic BP (P N .001), and low-frequency domain values (P = .006). After the recovery period, HRV index (P = .42) and high-frequency (HF) (P = .94) values were similar to baseline levels in the massage group, whereas the HRV index tended (P = .05) to be lower and the HF was significantly (P b .01) lower vs baseline values in the placebo group, which also showed a tendency (P = .06) for HF to be lower than after the exercise. Likewise, diastolic BP returned to baseline levels in the massage group (P = .45) but remained lower in the placebo group (P = .02). Conclusion: Myofascial release massage favors the recovery of HRV and diastolic BP after high-intensity exercise (3 Wingate tests) to preexercise levels.

The contributions of this article are twofold. One is a procedure for determining the angular velocity profile in seated cycling that maintains the total mechanical energy of both legs constant. A five-bar linkage model (thigh, shank, foot, crank and frame) of seated (fixed hip) cycling served for the derivation of the equations to compute potential and kinetic energies of the leg segments over a complete crank cycle. With experimentally collected pedal angle data as input, these equations were used to compute the total combined mechanical energy (sum of potential and kinetic energies of the segments of both legs) for constant angular velocity pedalling at 90rpm. Total energy varied indicating the presence of internal work. Motivated by a desire to test the hypothesis that reducing internal work in cycling will reduce energy expenditure, a procedure was developed for determining the angular velocity profile that eliminated any change in total energy. Using data recorded from five subjects, this procedure was used to determine a reference profile for an average equivalent cadence of 90 rpm. The phase of this profile is such that highest and lowest angular velocities occur when the cranks are near vertical and horizontal respectively. The second contribution is the testing of the hypothesis that the reference angular velocity profile serves to effectively reduce internal work for the subjects whose data were used to develop this profile over the range of pedalling rates (SCrlOO rpm) naturally preferred. In this range, the internal work was decreased a minimum of 48% relative to the internal work associated with constant angular velocity pedalling. The acceptance of this hypothesis has relevance to the protocol for future experiments which explore the effect of reduced internal work on energy expenditure in cycling. HA

The physical inactivity among women is a major behavioural risk factor that increases the rate of obesity and related health problems. This paper provides an overview of the health benefits increasing physical activity of young women cycling and breaches the significant barriers; the paper explores the challenges associated with women and promoting cycling as a travel mode to a workspace being an affordable and zero carbon mode of transit. This paper is to understand the benefits of an affordable and sustainable mode of transport, minimizing the environmental impacts and also encourage increased productivity at workspace through cycling. Thus, promoting women revolutionize self-esteem and being able to locomote independently of your own energy. The research objective was to study the social, physical and psychological factors involved in bicycle to work, to encourage a healthy lifestyle and to prioritize bicycling over a motorist and other transportation. This paper concludes strategies that can be implemented by the employers for encouraging women bicycling and to improve potential physical and mental health.

The effect of elevated human muscle temperature on energy turnover was investigated during cycling exercise (at 85 % of (VO(2)max)) at a contraction frequency of 60 revs min(-1). Muscle temperature was passively elevated prior to exercise by immersion of the legs in a hot water bath (42 degrees C). During exercise at this low pedalling rate, total energy turnover was higher (P<0.05) when muscle temperature was elevated compared with normal temperature (70.4+/-3.7 versus 66.9+/-2.4 kJ min(-1), respectively). Estimated net mechanical efficiency was found to be lower when muscle temperature was elevated. A second experiment was conducted in which the effect of elevated human muscle temperature on energy turnover was investigated during cycling exercise (at 85 % of (VO(2)max)) at a contraction frequency of 120 revs min(-1). Under the conditions of a high pedalling frequency, an elevated muscle temperature resulted in a lower energy turnover (P<0.05) compared with the normal muscle...

This study investigated risk compensation by cyclists in response to bicycle helmet wearing by observing changes in cycling behavior, reported experience of risk, and a possible objective measure of experienced risk. The suitability of heart rate variability (HRV) as an objective measure of experienced risk was assessed beforehand by recording HRV measures in nine participants watching a thriller film. We observed a significant decrease in HRV in line with expected increases in psychological challenge presented by the film. HRV was then used along with cycling pace and self-reported risk in a field experiment in which 35 cyclist volunteers cycled 0.4 km downhill, once with and once without a helmet. Routine helmet users reported higher experienced risk and cycled slower when they did not wear their helmet in the experiment than when they did wear their helmet, although there was no corresponding change in HRV. For cyclists not accustomed to helmets, there were no changes in speed, perceived risk, or any other measures when cycling with versus without a helmet. The findings are consistent with the notion that those who use helmets routinely perceive reduced risk when wearing a helmet, and compensate by cycling faster. They thus give some support to those urging caution in the use of helmet laws.

Purpose: Commencing selected workouts with low muscle glycogen availability augments several markers of training adaptation compared with undertaking the same sessions with normal glycogen content. However, low glycogen availability reduces the capacity to perform high-intensity (985% of peak aerobic power (V O 2peak )) endurance exercise. We determined whether a low dose of caffeine could partially rescue the reduction in maximal self-selected power output observed when individuals commenced high-intensity interval training with low (LOW) compared with normal (NORM) glycogen availability. Methods: Twelve endurancetrained cyclists/triathletes performed four experimental trials using a double-blind Latin square design. Muscle glycogen content was manipulated via exercise-diet interventions so that two experimental trials were commenced with LOW and two with NORM muscle glycogen availability. Sixty minutes before an experimental trial, subjects ingested a capsule containing anhydrous caffeine (CAFF, 3 mg j1 Ikg j1 body mass) or placebo (PLBO). Instantaneous power output was measured throughout high-intensity interval training (8 Â 5-min bouts at maximum self-selected intensity with 1-min recovery). Results: There were significant main effects for both preexercise glycogen content and caffeine ingestion on power output. LOW reduced power output by approximately 8% compared with NORM (P G 0.01), whereas caffeine increased power output by 2.8% and 3.5% for NORM and LOW, respectively, (P G 0.01). Conclusion: We conclude that caffeine enhanced power output independently of muscle glycogen concentration but could not fully restore power output to levels commensurate with that when subjects commenced exercise with normal glycogen availability. However, the reported increase in power output does provide a likely performance benefit and may provide a means to further enhance the already augmented training response observed when selected sessions are commenced with reduced muscle glycogen availability.

Objective. To assess the predictors of uptake and maintenance of walking and cycling, and of switching to the car as the usual mode of travel, for commuting. Methods. 655 commuters in Cambridge, UK reported all commuting trips using a seven-day recall instrument in 2009 and 2010. Individual and household characteristics, psychological measures relating to car use and environmental conditions on the route to work were self-reported in 2009. Objective environmental characteristics were assessed using Geographical Information Systems. Associations between uptake and maintenance of commuting behaviours and potential predictors were modelled using multivariable logistic regression. Results. Mean within-participant changes in commuting were relatively small (walking: + 3.0 min/ week, s.d. = 66.7; cycling: − 5.3 min/week, s.d. = 74.7). Self-reported and objectively-assessed convenience of public transport predicted uptake of walking and cycling respectively, while convenient cycle routes predicted uptake of cycling and a pleasant route predicted maintenance of walking. A lack of free workplace parking predicted uptake of walking and alternatives to the car. Less favourable attitudes towards car use predicted continued use of alternatives to the car. Conclusions. Improving the convenience of walking, cycling and public transport and limiting the availability of workplace car parking may promote uptake and maintenance of active commuting.

The aim of this study was to describe and evaluate physiological parameters as a control tool for the monitoring of training in a group of elite cyclists during one season of training. The study is divided into two periods (winter or ''volume'' mesocycle and spring or ''intensity'' mesocycle) between the tests that they carried out in the laboratory, consisting of a ramp test to exhaustion (work load increases 25 W X min(-1)) and a maximal lactate steady state (MLSS) test on a cycle ergometer. Macronutrients and hematological variables were recorded during the test periods as were the volume and the intensity of training sessions during the whole period of the study. The physiological data were similar to those previously reported for professional cyclists (approximately 450 Watts, approximately 78 mL x kg(-1) x min(-1)) and the values for the MLSS also agree with previous studies (approximately 250 Watts). Subjects improved the first ventilatory thre...

During the early period of running after cycling, EMG patterns of the leg are modified in only some highly trained triathletes. The majority of studies have analysed muscle EMG patterns at arbitrary, predetermined time points. The purpose of this study was to examine changes to EMG patterns of the lower limb at physiologically determined times during the cycle-run transition period to better investigate neuromuscular adaptations. Six highly trained triathletes completed a 10min isolated run (IR), 30min of rest, then a 20min cycling procedure, before a 10min transition run (C-R). Surface EMG activity of eight lower limb muscles was recorded, normalised and quantified at four time points. Oxygen uptake and heart rate values were also collected. Across all muscles, mean (±SD) EMG patterns, demonstrated significant levels of reproducibility for each participant at all four time points (α<0.05; r=0.52-0.97). Mean EMG patterns during C-R correlated highly with the IR patterns (α<0.0...

Rationale Salbutamol may affect lung function and exercise performance differently in individuals with and without asthma. Objectives To compare the effects of inhaled salbutamol on lung function, exercise performance and respiratory parameters during cycling exercise in athletes with a positive response to a eucapnic voluntary hyperpnoea (EVH+) and negative (EVH−) challenge, indicative of exercise-induced bronchoconstriction. Methods In a randomised controlled trial with a crossover design, a total of 49 well-trained male athletes (14 EVH+ and 35 EVH−) performed two simulated 10 km time-trials on a cycle ergometer 60 min after the inhalation of either 400 μg of salbutamol or a placebo. Lung function, assessed by forced expiratory volume in 1 s, was measured immediately before and 30 min after inhalation. Performance was measured by mean power output. Measurements & main results Despite a significant increase in lung function after the inhalation of salbutamol compared to the placebo (p<0.001), salbutamol did not affect athletes' perceptions of dyspnoea (p>0.05) or leg exertion (p>0.05) during exercise. Salbutamol did not affect mean power output: EVH+ and EVH− athletes averaged 4.0 (0.5) and 4.1 (0.5) W/kg after salbutamol and 4.0 (0.5) W/kg and 4.0 (0.4) W/kg after placebo, respectively (p>0.05 for each comparison). Conclusions The inhalation of salbutamol induced a significant increase in resting lung function in EVH+ and EVH− athletes but this improvement in lung function did not translate to improved exercise performance. Salbutamol had no discernible effect on key ventilatory and exercise parameters regardless of EVH challenge outcome.

Eight competitive cyclists [mean peak oxygen consumption, ( O 2peak ) = 65 ml á min A1 á kg A1 ] undertook two 60-min cycle ergometer time trials at 32°C and 60% relative humidity. The time trials were split into two 30-min phases: a ®xed-workload phase and a variable-workload phase. Each trial was preceded by ingestion of either a glycerol solution [1 g á kg A1 body mass (BM) in a diluted carbohydrate (CHO)-electrolyte drink] or a placebo of equal volume (the diluted CHOelectrolyte drink). The total¯uid intake in each trial was 22 ml á kg A1 BM. A repeated-measures, double blind, cross over design with respect to glycerol was employed. Glycerol ingestion expanded body water by »600 ml over the placebo treatment. Glycerol treatment signi®cantly increased performance by 5% compared with the placebo group, as assessed by total work in the variableworkload phase (P < 0.04). There were no signi®cant dierences in rectal temperature, sweat rate or cardiac frequency between trials. Data indicate that the glycerolinduced performance increase did not result from plasma volume expansion and subsequently lower core temperature or lower cardiac frequencies at a given power output as previously proposed. However, during the glycerol trial, subjects maintained a higher power output without increased perception of eort or thermal strain.

Undisputedly, traffic crashes constitute a public health concern whose impact and importance have been increasing during the past few decades. Specifically, road safety data have systematically shown how cyclists are highly vulnerable to suffering traffic crashes and severe injuries derived from them. Furthermore, although the empirical evidence is still very limited in this regard, in addition to other human factors involved in cycling crashes, distractions while cycling appear to be a major contributor to the road risk of cyclists. The main objectives of this study were, first, to explore the prevalence and trends of cycling distractions within an international sample of bike users, and second, to determine the influence of such distractions on road crashes suffered by cyclists, simultaneously considering the explanatory role of risky behaviors (errors and traffic violations) as potentially mediating variables between cycling distractions and traffic crashes. For this cross-sectio...

The purpose of this article is to investigate the shifting semiotic meanings of bicycles within the cultural context of contemporary China. I seek to interrogate the ways in which the symbolic capital of bicycles becomes established, reformulated, and reconstituted through different social structures. By looking at the shifting social meaning of riding bicycles, I illuminate the ways that social forces define and shape commodities. Informed by discourse analysis of online forums and ethnographic research, this article sheds light on the ways in which ordinary people and national initiatives use material objects and physical culture to remake themselves in an increasingly globalized and capitalistic world.

The purpose of this study was to determine the eVects of beta-alanine supplementation and high-intensity interval training (HIIT) on electromyographic fatigue threshold (EMG FT ) and eYciency of electrical activity (EEA). A total of 46 men completed four, 2-min work bouts on a cycle ergometer. Using bipolar surface electrodes, the EMG amplitude was averaged and plotted over the 2-min. The resulting slopes were used to calculate EMG FT and EEA. Following initial testing, all participants were randomly assigned to either placebo (PL; n = 18), beta-alanine (BA; n = 18) or control groups (CON; n = 10). Following randomization, participants engaged in 6 weeks of HIIT training. SigniWcant improvements in EMG FT and EEA resulted for both training groups. In conclusion, HIIT appeared to be the primary stimulus eVecting EMG FT or EEA, suggesting adaptations from HIIT may be more inXuential than increasing skeletal muscle carnosine levels on delaying fatigue in recreationally active men.

It is believed that brain derived neurotrophic factor (BDNF) plays an important role in neuronal growth, transmission, modulation and plasticity. Single bout of exercise can increase plasma BDNF concentration [BDNF](p) in humans. It was recently reported however, that elevated [BDNF](p) positively correlated with risk factors for metabolic syndrome and type 2 diabetes mellitus in middle age group of subjects. On the other hand it is well established that endurance training decreases the risk of diabetes and development of metabolic syndrome. In the present study we have examined the effect of 5 weeks of moderate intensity endurance training on the basal and the exercise induced changes in [BDNF](p) in humans. Thirteen young, healthy and physically active men (mean +/- S.E: age 22.7 +/- 0.5 yr, body height 180.2 +/- 1.7 cm, body weight 77.0 +/- 2.5 kg, V(O2max) 45.29 +/- 0.93 ml x kg-1 x min(-1)) performed a five week endurance cycling training program, composed mainly of moderate in...

The aims of this study were to measure the aerodynamic drag in professional cyclists, to obtain aerodynamic drag reference values in static and effort positions, to improve the cyclists' aerodynamic drag by modifying their position and cycle equipment, and to evaluate the advantages and disadvantages of these modifications. The study was performed in a wind tunnel with five professional cyclists. Four positions were assessed with a time-trial bike and one position with a standard racing bike. In all positions, aerodynamic drag and kinematic variables were recorded. The drag area for the timetrial bike was 31% higher in the effort than static position, and lower than for the standard racing bike. Changes in the cyclists' position decreased the aerodynamic drag by 14%. The aero-helmet was not favourable for all cyclists. The reliability of aerodynamic drag measures in the wind tunnel was high (r 4 0.96, coefficient of variation 5 2%). In conclusion, we measured and improved the aerodynamic drag in professional cyclists. Our results were better than those of other researchers who did not assess aerodynamic drag during effort at race pace and who employed different wheels. The efficiency of the aero-helmet, and the validity, reliability, and sensitivity of the wind tunnel and aerodynamic field testing were addressed.

Most mathematical models of athletic training require the quantification of training intensity and quantity or 'dose'. We aim to summarize both the methods available for such quantification, particularly in relation to cycle sport, and the mathematical techniques that may be used to model the relationship between training and performance. Endurance athletes have used training volume (kilometres per week and/or hours per week) as an index of training dose with some success. However, such methods usually fail to accommodate the potentially important influence of training intensity. The scientific literature has provided some support for alternative methods such as the session rating of perceived exertion (sRPE ((Author: this abbreviation is not used again in the abstract-ok to delete?))), which provides a subjective quantification of the intensity of exercise; and the heart rate-derived training impulse (TRIMP) method, which quantifies the Approval for publication Signed Date Number of amended pages returned AQ3

A major criticism of present models of the energetics and mechanics of sprint running concerns the application of estimates of parameters which seem to be adapted from measurements of running during actual competitions. This study presents a model which does not perpetuate this solecism. Using data obtained during supra-maximal cycle ergometer tests of highly trained athletes, the kinetics of the anaerobic and aerobic pathways were modelled. Internal power wasted in the acceleration and deceleration of body limbs and the power necessary to overcome air friction was calculated from data in the literature. Assuming a mechanical efficiency as found during submaximal cycling, a power equation was constructed which also included the power necessary to accelerate the body at the start of movement. The differential equation thus obtained was solved through simulation. The model appeared to predict realistic times at 100 m (10.47 s), 200 m (19.63 s) and 400 m (42.99 s) distances. By comparison with other methods it is argued that power equations of locomotion should include the concept of mechanical efficiency.

– Intrusive luxation is one of the most severe types of dental trauma. The occurrence of pulp necrosis in intruded teeth with open apices is 100%. The risk of development of inflammatory or replacement root resorptions is high. Thus, endodontic intervention is required soon ...

Accurate determination of speed is important in many studies of human and animal locomotion. Some global positioning system (GPS) receivers can data log instantaneous speed. The speed accuracy of these systems is, however, unclear with manufacturers reporting velocity accuracies of 0.1-0.2 ms À1 . This study set out to trial non-differential GPS as a means of determining speed under real-life conditions.

Purpose: The purpose of this study was to assess the effects of induced metabolic alkalosis, via sodium bicarbonate (NaHCO 3 ) ingestion, on muscle metabolism and power output during repeated short-duration cycle sprints. Methods: Ten active females (mean Ϯ SD: age ϭ 19 Ϯ 2 yr, V O 2max ϭ 41.0 Ϯ 8.8 mL·kg Ϫ1 ·min Ϫ1 ) ingested either 0.3 g·kg Ϫ1 NaHCO 3 or 0.207 g·kg Ϫ1 of NaCl (CON), in a double-blind, random, counterbalanced order, 90 min before performing a repeated-sprint ability (RSA) test (5 ϫ 6-s all-out cycle sprints every 30 s). Results: Compared with CON, there was a significant increase in resting blood bicarbonate concentration [HCO 3 Ϫ ] (23.6 Ϯ 1.1 vs 30.0 Ϯ 3.0 mmol·L Ϫ1 ) and pH (7.42 Ϯ 0.02 vs 7.50 Ϯ 0.04), but no significant difference in resting lactate concentration [La Ϫ ] (0.8 Ϯ 0.2 vs 0.8 Ϯ 0.3 mmol·L Ϫ1 ) during the NaHCO 3 trial. Muscle biopsies revealed no significant difference in resting muscle [La Ϫ ], pH, or buffer capacity (␤ in vitro ) between trials (P Ͼ 0.05). Compared with CON, the NaHCO 3 trial resulted in a significant increase in total work (15.7 Ϯ 3.0 vs 16.5 Ϯ 3.1 kJ) and a significant improvement in work and power output in sprints 3, 4, and 5. Despite no significant difference in posttest muscle pH between conditions, the NaHCO 3 trial resulted in significantly greater posttest muscle [La Ϫ ]. Conclusions: As NaHCO 3 ingestion does not increase resting muscle pH or ␤ in vitro , it is likely that the improved performance is a result of the greater extracellular buffer concentration increasing H ϩ efflux from the muscles into the blood. The significant increase in posttest muscle [La Ϫ ] in NaHCO 3 suggests that an increased anaerobic energy contribution is one mechanism by which NaHCO 3 ingestion improved RSA.

Bicycle-related injuries account for an important proportion of road injuries all over the world. As only few reports have focused on the characteristics of maxillofacial fractures sustained in bicycle accidents, the purpose of this study was to present and compare epidemiological data about bicycle-related maxillofacial injuries in two European centers between 2001 and 2010. Bicycle-related facial fractures occurred in 105 patients (79 males, 26 females) in Turin, with a percentage of 5.77 among all facial fractures, and in 103 patients (55 males, 50 females) in Amsterdam, with a percentage of 19.69. The major risk groups include young people between their first to third decades. The mandible is the most frequently involved facial bone. Among mandibular injuries the most commonly involved site was the condyle. Bicycle-related injuries must be considered an important etiological factor in maxillofacial fractures with typical patterns, such as a peculiar seasonal incidence.

The purpose of this study was to evaluate the trunk muscles activity of hemiparetic and control subjects during selected therapeutic exercises with surface electromyography (sEMG). The sEMG evaluation included 12 subjects presenting hemiparesis after having suffered a unilateral stroke and 12 apparently healthy subjects. A 16-channel sEMG system was used; data were band pass filtered from 20 to 450 Hz. The signal was normalized through reference voluntary contraction (RVC) and presented in percentage. The exercises used in the evaluations were trunk flexion and trunk extension. Rectus abdominis presented greater activation on the paretic side of the experimental group than on the corresponding side of the control group (P = 0.035) (Cohen's d ¼ 0:94). During leg elevation, the non-paretic obliquus externus abdominis showed greater activation than in other exercises (P = 0.019) (Cohen's d ¼ 0:75). No intergroup differences were found for either erectus spinae activity or contraction onset. Experimental group subjects showed muscle activity alterations, principally in the rectus abdominis, indicating the occurrence of compensatory strategies.