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The acute effects of prior cycling cadence on running performance and kinematics
Abstract
Purpose: To determine if cycling cadence affects subsequent running speed through changes in stride frequency. Methods: Thirteen male triathletes completed three sessions of testing on separate days. During the first session (control condition), the participants completed a 30-min cycling bout of high intensity at their preferred cadence, immediately followed by a 3200-m run at race effort. During the second and third sessions (fast condition and slow condition), the participants repeated the protocol but with a cycling cadence 20% faster or 20% slower than the control condition. Results: After cycling at a fast cadence, the 3200-m run time averaged nearly a min faster than after cycling at a slow cadence. Running stride frequency after cycling at a fast cadence was significantly greater than after cycling at a normal or slow cadence. Stride length did not differ between conditions. Joint kinematics at foot strike, mid-stance, toe-off, and mid-swing were not different between conditions. Conclusion: Increased cycling cadence immediately before running increased stride frequency and, as a result, increased speed.
... However, when comparing to triathlon related research it is evident that prior cycling and swimming has an impact on the SR and SL chosen during final run leg (4,12,16,20). Hausswirth et al., (16) reported a decrease in running SL following cycling with no change in SR. Other researchers have concluded that as fatigue increases during running, SR and SL, characteristics begin to alter, with a decrease in SL, and if running velocity is to be maintained an increase in SR (9,16,41). ...
... A limitation of this study to note is that no SR or SL data were collected from the participants in an unfatigued, controlled environment. Previous research has indicated that prior activity such as swimming, cycling or running prior to completing a 10 km run increases fatigue which can alter running mechanics (4,12,16,20). That is, there is a possibility that the participants may choose different SR/SL characteristics while running at a similar speed without prior cycling and or swimming which may have a stronger relationship to the triathletes' body mass or height. ...
Previous research has suggested that a degree of predictability exists in the relationship between self-selected running stride rates (SR) and stride lengths (SL) with measures of body size such as mass, height and limb lengths. Significant correlations have also been revealed between these body size measures and performance and between SL and performance. However, there is also evidence to suggest that triathlon performance may be related to maintaining a longer SL during the final run. Hence, the aim of this investigation was to examine whether there was any relationship between SR and SL, with body masses and heights of senior elite triathletes during the run stage of a triathlon. The SRs and SLs of 37 male senior elite Triathlon World Championships competitors were analysed via videography and Video Expert II Coach. These values were correlated with the athletes’ body masses and heights (p<0.01). The results indicated a limited relationship between height and mass with SR in the early stages of the run. However, a significant, positive correlation existed between SL and height at all points from 3 km to the end of the run. Those triathletes who were taller used longer strides. Further research is warranted to examine the effects of cycling on the subsequent run discipline during triathlon and if body size and shape of triathletes have evolved as the young sport of triathlon develops.
... Most of the studies have shown that performance and the stride patterns during running after cycling are greatly influenced by the pedalling frequency during cycling. [87,89,95,182,184] However, the conclusions drawn from such studies are equivocal: Gottschall and Palmer [184] reported that by using a high cadence (FCC +20%) during a 30-minute cycle time trial, the subsequent 3 km running performance was 1 minute faster than by cycling at slow cadence (FCC -20%). This was due to an increased stride frequency whereas stride length was unchanged. ...
... Most of the studies have shown that performance and the stride patterns during running after cycling are greatly influenced by the pedalling frequency during cycling. [87,89,95,182,184] However, the conclusions drawn from such studies are equivocal: Gottschall and Palmer [184] reported that by using a high cadence (FCC +20%) during a 30-minute cycle time trial, the subsequent 3 km running performance was 1 minute faster than by cycling at slow cadence (FCC -20%). This was due to an increased stride frequency whereas stride length was unchanged. ...
The purpose of this review was to provide a synopsis of the literature concerning the physiological differences between cycling and running. By comparing physiological variables such as maximal oxygen consumption (V O(2max)), anaerobic threshold (AT), heart rate, economy or delta efficiency measured in cycling and running in triathletes, runners or cyclists, this review aims to identify the effects of exercise modality on the underlying mechanisms (ventilatory responses, blood flow, muscle oxidative capacity, peripheral innervation and neuromuscular fatigue) of adaptation. The majority of studies indicate that runners achieve a higher V O(2max) on treadmill whereas cyclists can achieve a V O(2max) value in cycle ergometry similar to that in treadmill running. Hence, V O(2max) is specific to the exercise modality. In addition, the muscles adapt specifically to a given exercise task over a period of time, resulting in an improvement in submaximal physiological variables such as the ventilatory threshold, in some cases without a change in V O(2max). However, this effect is probably larger in cycling than in running. At the same time, skill influencing motor unit recruitment patterns is an important influence on the anaerobic threshold in cycling. Furthermore, it is likely that there is more physiological training transfer from running to cycling than vice versa. In triathletes, there is generally no difference in V O(2max) measured in cycle ergometry and treadmill running. The data concerning the anaerobic threshold in cycling and running in triathletes are conflicting. This is likely to be due to a combination of actual training load and prior training history in each discipline. The mechanisms surrounding the differences in the AT together with V O(2max) in cycling and running are not largely understood but are probably due to the relative adaptation of cardiac output influencing V O(2max) and also the recruitment of muscle mass in combination with the oxidative capacity of this mass influencing the AT. Several other physiological differences between cycling and running are addressed: heart rate is different between the two activities both for maximal and submaximal intensities. The delta efficiency is higher in running. Ventilation is more impaired in cycling than in running. It has also been shown that pedalling cadence affects the metabolic responses during cycling but also during a subsequent running bout. However, the optimal cadence is still debated. Central fatigue and decrease in maximal strength are more important after prolonged exercise in running than in cycling.
... Portanto sugere-se que a seleção da cadência mais elevada no ciclismo melhora o desempenho do atleta na corrida com aumento da frequência de passada, resultando assim, em aumento da velocidade média durante a corrida. 46 Por outro lado, ao comparar o efeito de diferentes cadências (60-100 rpm) de ciclismo no desempenho da corrida nos 3000 m não foram encontradas diferenças entre elas, contudo a escolha de 60 rpm foi associada com uma fração mais elevada de VO 2 máximo sustentada durante a corrida em comparação com as outras condições. Os autores acreditam que há uma maior contribuição do sistema aeróbio em cadências mais baixas, que podem assim, retardar a fadiga por mais tempo na etapa da corrida. ...
O triatlo caracteriza-se por ser um esporte múltiplo composto por três modalidades: natação, ciclismo e corrida que ocorrem nessa ordem e em sequência. Na etapa da corrida, o atleta sofre efeitos decorrentes das modalidades que a antecederam (natação e ciclismo) podendo assim, alterar parâmetros biomecânicos e fisiológicos da corrida. Objetivo: o objetivo deste estudo foi revisar aspectos fisiológicos, bem como alterações na biomecânica da corrida em triatletas. Método: a busca foi realizada nas bases de dados: Scielo, Pubmed e Google Acadêmico. Resultados: foram incluídos na revisão 48 artigos e um livro. Considerações finais: A corrida de triatletas apresenta alterações na eficiência ventilatória, no VO2 e na cinemática angular, principalmente do joelho e tornozelo. Além disso, triatletas exibem uma maior inclinação do tronco contribuindo para padrões mais econômicos de movimento, especialmente em atletas altamente treinados.
... In cycling there are different rules for different distances, in the case of the Olympic races it is permitted to use the vacuum reducing caloric expenditure and physical exertion [8] significantly improving athlete's running performance [9], already for the longer distances this strategy is not permitted, causing all athletes to start the running in similar conditions of physical wear and tear. The run is the last modality to be performed and researchers report that this running performance should be harmed by muscle stress resulting from the physical exertion of previous tasks [10]. ...
The aim of the study was to analyze which modality (swimming, cycling or running) may interfere significantly to the final performance of different triathlon events. The present study observed the last five results of Olympic Distance, Half Distance and Full Distance (Ironman) of World Championship from 2010 to 2015. The athlete’s times were tabulated separate per: swimming time, cycling time, running time and total time. The sample was divided in two groups: (G1) athletes who were classified among the five best of each step and (G2) the athletes classified between sixth and tenth place. The total sample was composed by male and female athletes (N=300). Statistical analysis: the regression, correlation and comparison model was used between two groups for the three distances of triathlon tests and for all investigated variables. The results pointed that for each type of test and athlete one modality may be more deterministic to the final performance. Therefore, the training programs should consider that triathlon is one only modality; thus, the training planning should be focused in a unique way taking into account the specificity of race.
... Although there is variety of research on the influence of completing multiple segments on physiological, biomechanical and performance measures ( Bonacci et al., 2010;Bonacci et al., 2013;Cala et al., 2009;Chapman et al., 2008;Gottschall and Plamer, 2002;Hue et al., 1999), to our knowledge there is no research focused specifically on transitions. Even though, transition length (and therefore time) as well as terrain can vary greatly between races, it is important to understand the physiological demands of transitions in order to benefit overall race performance. ...
Triathletes exiting the swim portion of an event have to decide on how and when to take a wetsuit off (if worn). The purpose of this study was to determine the physiological cost of running while not using a wetsuit, carrying a wetsuit, wearing a wetsuit halfway down or wearing a wetsuit fully up. Participants (n = 20, 30.9 ± 8.7 yrs, 1.71 ± 0.08 m, 71.6 ± 9.5 kg) completed four 5 min running conditions: 1) not wearing the wetsuit, 2) wearing the wetsuit fully up, 3) wearing the wetsuit halfway down, and 4) carrying the wetsuit. A rate of oxygen uptake, a heart rate, ratings of perceived exertion and stride frequency were measured and were each influenced by wetsuit condition (p < 0.05). Each variable (i.e., a rate of oxygen uptake, a heart rate, stride frequency) was lower during running while not wearing the wetsuit vs. any other condition (p < 0.05). The rate of oxygen uptake was greatest during wearing the wetsuit halfway down vs. any other condition (p < 0.05). The heart rate was not different between any of the combinations of either wearing the wetsuit fully up or halfway down or carrying the wetsuit (p > 0.05). The rating of perceived exertion was greater during wearing the wetsuit halfway down vs. carrying the wetsuit (p < 0.05). Stride frequency was lower during not wearing the wetsuit vs. wearing the wetsuit halfway down or fully up (p < 0.05). It was concluded that running with the wetsuit halfway down resulted in the greatest rate of oxygen uptake, heart rate and rating of perceived exertion.
... Since these two tests involve stepping, it is possible that speed-based exercise can facilitate locomotor central pattern generators, which are impaired in this population (Selinov et al, 2013). Others have observed improved gait parameters following a single session speed-dependent treadmill exercise in PD (Pohl et al, 2003) and research on triathletes has shown that a preceding bout of high cadence cycling improves subsequent running speed through an increase in stride frequency (Gottschall and Palmer, 2002), with implications for perseveration (Hudson, 1968). There is an increasing amount of evidence supporting central adaptations following speed-based exercise. ...
There is growing evidence that speed-based exercise training benefits people with Parkinson's disease (PD). The present study investigates the effects of a single session of volitional, high-speed cycling intervals on a battery of timed functional tests selected for their relevance to the symptom of bradykinesia. Ten subjects with PD (Hoehn-Yahr stage ≤ 3.0) participated in a familiarization session and three test sessions. Functional testing occurred before and after 30 minute sessions in which subjects performed no exercise (NO), pedaled at their preferred cadence (PC), or performed 20, 15-second intervals of high-speed low-resistance cycling (HS-LR). In addition to testing the exercise effects in a within-subjects design, we provide test–retest reliability data, minimal detectable change scores, and correlations among the selected functional tests. Despite the relatively low dose of speed-based exercise, HS-LR elicited significant (p < 0.05) improvements in the four square step test and 10 m walk test. Excepting reaction times, there was high reliability and adequate sensitivity to detect moderate and small differences. Strong correlations among tests of mobility inform the future selection of measures in the experimental design. In addition to what is known about continuous exercise sessions involving high-speed exercise, the present results suggest that brief intervals of HS-LR bicycling are promising and should be examined in a longer duration exercise program.
... Gottschall and Palmer 22 found that a high cadence at the end of the cycling resulted in a high-stride frequency at the beginning of the running part, due to the phenomenon known as perseveration, i.e., persons performing a rhythmic activity for an extended period of time will involuntary continue this movement pattern. 24,25 In the context of multisport events such as triathlons, it is possible that perseveration would cause individuals to unintentionally begin the running bout with a stride frequency similar to the cadence of the previous cycling bout. 23 That could explain the low stride frequencies values and their tendency to decrease obtained in the present study. ...
The most strategic part of a triathlon is the cycle-run transition. However, all the studies about this situation have been carried out in laboratory conditions and there is a need to perform this kind of study during competition, when the triathletes are highly motivated and the effort is maximum.1 Therefore, the aims of the present study were: 1) to determine the effect of prior 40-km cycling on the 10-km running kinematics during a Triathlon World Cup competition, and 2) to examine the possible differences between males and females.
Ten men and ten women, selected among the first ten competitors at the end of the cycling part at Madrid 2006 BG Triathlon World Cup, were enrolled in the study. The kinematic analysis was carried out using a photogrammetric technique (DLT algorithms) in the saggital plane (2D).
There are significant differences (P<0.05) in men's stride length and velocity between the first and the last lap. Also, significant differences (P<0.05) were found between men and women in many of the variables analyzed.
The previous cycling does not affect the subsequent running efficiency during a elite triathlon competition. On the other hand, the running technique profile during a triathlon competition is very different between men and women.
... In this case, the impact of cycling cadence during a cycle-run combination has received great attention from researchers and coaches. [6,34,[38][39][40] In a simulated triathlon, Hausswirth et al. [34] first demonstrated an indirect effect of cadence upon subsequent running performance. In this study, triathletes selected a cadence of 95 rpm during the drafting condition [reproduced from Pugh, [37] with permission from Blackwell Publishing]. ...
This review focuses on strategic aspects that may affect performance in a long-duration Olympic event, the Olympic distance triathlon. Given the variety of races during the Olympic Games triathlon, strategic aspects include improving technological features as well as energetics factors affecting overall triathlon performance. During the last decade, many studies have attempted to identify factors reducing the metabolic load associated (or not) with the development of fatigue process by analysing the relationship between metabolic and biomechanical factors with exercise duration. To date, a consensus exists about the benefit of adopting a drafting position during the swimming or the cycling part of the triathlon. Other potential strategic factors, such as the production of power output or the selection of cadence during the cycling or the running leg, are likely to affect the overall triathlon performance. Within this approach, pacing strategies are observed by elite athletes who swim or cycle in a sheltered position, inducing several changes of pace, intensity or stochastic shifts in the amplitude of the physiological responses. The analysis of these parameters appears to arouse some experimental and practical interest from researchers and coachers, especially for long-distance Olympic events.
En triatlón, una de las partes más duras y estratégicas del deporte es la transición del ciclismo a la carrera a pie. El principal problema de los estudios analizados es que han sido llevados a cabo en laboratorios, donde la poca especificidad de los tests utilizados representan un handicap. Tanto las variables fisiológicas (lactato y frecuencia cardiaca) como la velocidad muestran diferencias considerables entre los valores obtenidos en estudios de laboratorio y los obtenidos en competición. Por otro lado ya hay quien reclama la necesidad de realizar este tipo de estudios en situación real de competición, donde los triatletas se encuentran motivados plenamente y el esfuerzo es totalmente específico y máximo [1]. Por tanto, los objetivos del presente estudio fueron: a) analizar si existen diferencias en la biomecánica de carrera en comparando los valores obtenidos en competición con los de los estudios realizados en laboratorios; b) analizar si la eficiencia de carrera desciende en las primeras vueltas debido al ciclismo previo; y c) examinar las posibles diferencias que pudieran existir entre hombres y mujeres. Los resultados muestran diferencias significativas (p<0,05) entre géneros para la mayoría de las variables estudiadas. Asimismo, existen diferencias significativas (p<0,05) para la longitud de ciclo y la velocidad de los chicos entre vueltas.
The most strategic part of a triathlon is the cycle-run transition. According to the references found in the bibliography it is important to remark that authors have used non-specific tests, because physiological (lactate and heart rate) and velocity variables have shown considerable differences between the values obtained from laboratory-based studies and those from real competition. However, there is a need to perform these kind of studies in competition, when the triathletes are highly motivated and the effort is maximum [1] Therefore, the objectives of the present study were: A) to analyze the kinematic changes in running pattern comparing competition with laboratory-based studies; B) to analyse if the running efficiency drops at the first laps due to the previous cycling; C) to examine the possible differences between men and women. The results show significant differences (p<0.05) between men and women in many of the variables studied. Also, significant differences (p<0.05) were found in men’s stride length and velocity between laps.
Objective-The aim of the study was to find out the Relationship of Kinematical Variables with the performance of Sprinters. Methodology: For the purpose of this study 05 male National/ All India inter University sprinters were selected as subject. The age of the subject ranged from 18-25 years. The subject selected from Lucknow, Allahabad, and Varanasi District. The performance of the subject's taking by filming protocol by using Casio ex-f1 high speed camera .Silicon Coach Pro-7 Motion analysis software was used for collecting raw data. The raw data further statistically analyzed by SPSS-20 Version software. The data has been recorded only acceleration zone (50 meter distance) of the 100 meter race. There were two trials had given to the each subjects and the best trial was used for the analysis. Results: Result of the study have shown that,there was insignificant relationship found between all the selectedAll movements of living beings are governed by the laws of mechanics, as every movement is mechanical in nature involving locomotion of the body mass in space and time However, in contrast to the movements of non-living beings, which are subjected to mechanical laws, the movements of living bodies besides being governed by mechanical laws are also subjected to biological laws. Kinematical analysis is the process of measuring the kinematic quantities used to describe motion. In engineering, for instance, kinematic analysis may be used to find the range of movement for a given mechanism, and, working in reverse, kinematic synthesis designs a mechanism for a desired range of motion. In addition, kinematics applies algebraic geometry to the study of the mechanical advantage of a mechanical system or mechanism. Athletics is an exclusive collection of sporting events that involve competitive running, jumping, throwing, and walking. The most common types of athletics competitions are track and field, road running, cross country running, and walking. The simplicity of the competitions, and the lack of a need for expensive equipment, makes athletics one of the most commonly competed sports in the world. Athletics is mostly an individual sport, with the exception of relay races and competitions which combine athletes' performances for a team score, such as cross country. Sprinting is the fullest form of running performed over short distance in which maximum or near maximum effort can be sustained. Sprinting figures in the program of all major athletic championships including the Olympic game, in which the standard sprint event for men and women are the 100m, 200m, 400m, hurdle, as well as 4×100m and well as 4×400m relay. Stride Length-It is the linear distance from the point of heel strike of one lower extremity to the next heel strike of the same extremity. Stride Frequency-Stride frequency corresponds to the number strides that are completed in a specified time period. Running is a cyclic movement in which two
The aim of this study was to examine the effects of different pedalling cadences on the performance of a subsequent 10km treadmill run. Eight male triathletes (age 38.9 ± 15.4 years, body mass 72.2 ± 5.2 kg, and stature 176 ± 6 cm; mean ± SD) completed a maximal cycling test, one isolated run (10km), and then three randomly ordered cycle-run sessions (65 minutes cycling + 10km run). During the cycling bout of the cycle-run sessions, subjects cycled at an intensity corresponding to 70% Pmax while maintaining one of three cadences, corresponding to preferred cadence (PC), PC+15% (fast cadence) and PC-15% (slow cadence). Slow, preferred and fast cadences were 71.8 ± 3.0, 84.5 ± 3.6, and 97.3 ± 4.3 rpm, respectively (mean ± SD). Physiological variables measured during the cycle-run and isolated run sessions were VO2, VE, RER, HR, RPE, and blood lactate. Biomechanical variables measured during the cycle-run and isolated run sessions were running velocity, stride length, stride frequency, and hip and knee angles at foot-strike and toe-off. Running performance times were also recorded. A significant effect of prior cycling exercise was found on 10km running time (p = 0.001) without any cadence effect (p = 0.801, ω2 = 0.006) (49:58 ± 8:20, 49:09 ± 8:26, 49:28 ± 8:09, and 44:45 ± 6:27 min·s-1 for the slow, preferred, fast, and isolated run conditions, respectively; mean ± SD). However, during the first 500 m of the run, running velocity was significantly higher after cycling at the preferred and fast cadences than after the slow cadence (p < 0.05). Furthermore, the slow cadence condition was associated with a significantly lower HR (p = 0.012) and VE (p = 0.026) during cycling than in the fast cadence condition. The results confirm the deterioration in running performance completed after the cycling event compared with the isolated run. However, no significant effect of cycling cadence on running performance was observed within the cadence ranges usually used by triathletes.
Objectives:
To determine which commonly measured variables of cycling intensity are related to subsequent running economy in triathletes.
Design:
Cross-sectional laboratory study.
Methods:
Running economy was compared between a control run (no preceding cycle) and a run performed after a 45 min high-intensity cycle in eighteen triathletes. Power output, heart rate, rating of perceived exertion (RPE) and blood lactate concentration were monitored throughout the cycle. The relationship between measures of cycle intensity and the change in running economy was evaluated using Pearson's product moment correlation. Changes in running economy were also interpreted using the smallest worthwhile change (>2.4%) and grouped accordingly (i.e. impaired, no change, or improved running economy).
Results:
Triathletes' RPE at the end of the cycling bout was significantly associated with the change in running economy after cycling (r=0.57, p=0.01). Average RPE of the cycle bout and RPE at the end of the cycling bout were significantly different between groups, with higher RPE scores being related to impairments in running economy (p=0.04 and p=0.02 respectively).
Conclusions:
RPE during cycling is associated with subsequent running economy in triathletes. RPE is a simple, cost-effective measure that triathletes and their coaches can use in competition and training to control cycling intensity without the need for specialist equipment such as crank systems or blood analysers.
THE CYCLING LEG OF A TRIATHLON IMPOSES UNIQUE PHYSIOLOGICAL AND BIOMECHANICAL DEMANDS ON ATHLETES COMPARED WITH CYCLE RACING. BY RECOGNIZING THESE DIFFERENCES, ATHLETES AND COACHES CAN USE TRAINING PRACTICES TO OPTIMIZE ADAPTATIONS ACCORDING TO THE PRINCIPLE OF SPECIFICITY. THE PRIMARY EMPHASIS IS ON AERODYNAMIC FORM AND EFFICIENCY TRAINING.
Running is the most important discipline for Olympic triathlon success. However, cycling impairs running muscle recruitment and performance in some highly trained triathletes; though it is not known if this occurs in elite international triathletes. The purpose of this study was to investigate the effect of cycling in two different protocols on running economy and neuromuscular control in elite international triathletes. Muscle recruitment and sagittal plane joint angles of the left lower extremity and running economy were compared between control (no preceding cycle) and transition (preceded by cycling) runs for two different cycle protocols (20-minute low-intensity and 50-minute high-intensity cycles) in seven elite international triathletes. Muscle recruitment and joint angles were not different between control and transition runs for either cycle protocols. Running economy was also not different between control and transition runs for the low-intensity (62.4 +/- 4.5 vs. 62.1 +/- 4.0 ml/min/kg, p > 0.05) and high-intensity (63.4 +/- 3.5 vs. 63.3 +/- 4.3 ml/min/kg, p > 0.05) cycle protocols. The results of this study demonstrate that both low- and high-intensity cycles do not adversely influence neuromuscular control and running economy in elite international triathletes.
The aim of the present study was to determine the best pacing strategy to adopt during the initial phase of a short distance triathlon run for highly trained triathletes. Ten highly trained male triathletes completed an incremental running test to determine maximal oxygen uptake, a 10-km control run at free pace and three individual time-trial triathlons (1.5-km swimming, 40-km cycling, 10-km running) in a randomised order. Swimming and cycling speeds were imposed as identical to the first triathlon performed and the first run kilometre was done alternatively 5% faster (Tri-Run(+5%)), 5% slower (Tri-Run(-5%)) and 10% slower (Tri-Run(-10%)) than the control run (C-Run). The subjects were instructed to finish the 9 remaining kilometres as quickly as possible at a free self-pace. Tri-Run(-5%) resulted in a significantly faster overall 10-km performance than Tri-Run(+5%) and Tri-Run(-10%) (p < 0.05) but no significant difference was observed with C-Run (p > 0.05) (2,028 +/- 78 s vs. 2,000 +/- 72 s, 2,178 +/- 121 s and 2,087 +/- 88 s, for Tri-Run(-5%), C-Run, Tri-Run(+5%) and Tri-Run(-10%), respectively). Tri-Run(+5%) strategy elicited higher values for oxygen uptake, ventilation, heart rate and blood lactate at the end of the first kilometre than the three other conditions. After 5 and 9.5 km, these values were higher for Tri-Run(-5%) (p < 0.05). The present results showed that the running speed achieved during the cycle-to-run transition is crucial for the improvement of the running phase as a whole. Triathletes would benefit to automate a pace 5% slower than their 10-km control running speed as both 5% faster and 10% slower running speeds over the first kilometre involved weaker overall performances.
Previous studies have shown that cycling can directly influence neuromuscular control during subsequent running in some highly trained triathletes. A relationship between this altered neuromuscular control of running and musculoskeletal pain and injury has been proposed; however, this link has not been investigated.
This study aimed to evaluate the influence of cycling on neuromuscular control during subsequent running in highly trained triathletes with and without exercise-related leg pain (ERLP).
Participants were 34 highly trained triathletes: 10 triathletes with a history of ERLP and 24 training-matched control triathletes with no history of ERLP. Knee and ankle kinematics and leg muscle recruitment were compared between a baseline run (no prior exercise) and a transition run (preceded by cycling; i.e., run vs cycle run).
Knee and ankle joint kinematics were not different between baseline and transition runs for any triathletes: absolute mean difference (+/-95% confidence interval) was 1.49 degrees +/- 0.17 degrees. However, muscle recruitment was different between baseline and transition runs, defined by absolute mean difference in EMG amplitude > or = 10%, in 5 of 24 control triathletes (11/130 muscles exhibited altered recruitment) and in 5 of 10 triathletes with a history of ERLP (12/50 muscles exhibited altered recruitment). This represents a relative risk of 2.40 (0.89-6.50; P = 0.089) when defined by athletes and 2.62 (1.34-6.01; P < 0.01) when defined by muscles. The magnitude of change in muscle recruitment between baseline and transition runs was not different between control (14.10% +/- 2.34%) and ERLP triathletes (16.31% +/- 3.64%; P = 0.41).
This study demonstrates an association between ERLP in triathletes and their neuromuscular control when running off the bike.
To investigate the effect of cadence selection during the final minutes of cycling on metabolic responses, stride pattern, and subsequent running time to fatigue.
Eight triathletes performed, in a laboratory setting, two incremental tests (running and cycling) to determine peak oxygen uptake (VO2PEAK) and the lactate threshold (LT), and three cycle-run combinations. During the cycle-run sessions, subjects completed a 30 minute cycling bout (90% of LT) at (a) the freely chosen cadence (FCC, 94 (5) rpm), (b) the FCC during the first 20 minutes and FCC-20% during the last 10 minutes (FCC-20%, 74 (3) rpm), or (c) the FCC during the first 20 minutes and FCC+20% during the last 10 minutes (FCC+20%, 109 (5) rpm). After each cycling bout, running time to fatigue (Tmax) was determined at 85% of maximal velocity.
A significant increase in Tmax was found after FCC-20% (894 (199) seconds) compared with FCC and FCC+20% (651 (212) and 624 (214) seconds respectively). VO2, ventilation, heart rate, and blood lactate concentrations were significantly reduced after 30 minutes of cycling at FCC-20% compared with FCC+20%. A significant increase in VO2 was reported between the 3rd and 10th minute of all Tmax sessions, without any significant differences between sessions. Stride pattern and metabolic variables were not significantly different between Tmax sessions.
The increase in Tmax after FCC-20% may be associated with the lower metabolic load during the final minutes of cycling compared with the other sessions. However, the lack of significant differences in metabolic responses and stride pattern between the run sessions suggests that other mechanisms, such as changes in muscular activity, probably contribute to the effects of cadence variation on Tmax
The aim of this study was to investigate the metabolic responses to variable versus constant-intensity (CI) during 20-km cycling on subsequent 5-km running performance. Ten triathletes, not only completed one incremental cycling test to determine maximal oxygen uptake and maximal aerobic power (MAP), but also three various cycle-run (C-R) combinations conducted in outdoor conditions. During the C-R sessions, subjects performed first a 20-km cycle-time trial with a freely chosen intensity (FCI, approximately 80% MAP) followed by a 5-km run performance. Subsequently, triathletes were required to perform in a random order, two C-R sessions including either a CI, corresponding to the mean power of FCI ride, or a variable-intensity (VI) during cycling with power changes ranging from 68 to 92% MAP, followed immediately by a 5-km run. Metabolic responses and performances were measured during the C-R sessions. Running performance was significantly improved after CI ride (1118 +/- 72 s) compared to those after FCI ride (1134 +/- 64 s) or VI ride (1168 +/- 73 s) despite similar metabolic responses and performances reported during the three cycling bouts. Moreover, metabolic variables were not significantly different between the run sessions in our triathletes. Given the lack of significant differences in metabolic responses between the C-R sessions, the improvement in running time after FCI and CI rides compared to VI ride suggests that other mechanisms, such as changes in neuromuscular activity of peripheral skeletal muscle or muscle fatigue, probably contribute to the influence of power output variation on subsequent running performance.
Triathlon is a sport consisting of sequential swimming, cycling and running. The main diversity within the sport of triathlon resides in the varying event distances, which creates specific technical, physiological and nutritional considerations for athlete and practitioner alike. The purpose of this article is to review physiological as well as nutritional aspects of triathlon and to make recommendations on ways to enhance performance. Aside from progressive conditioning and training, areas that have shown potential to improve triathlon performance include drafting when possible during both the swim and cycle phase, wearing a wetsuit, and selecting a lower cadence (60-80 rpm) in the final stages of the cycle phase. Adoption of a more even racing pace during cycling may optimise cycling performance and induce a "metabolic reserve" necessary for elevated running performance in longer distance triathlon events. In contrast, drafting in swimming and cycling may result a better tactical approach to increase overall performance in elite Olympic distance triathlons. Daily energy intake should be modified to reflect daily training demands to assist triathletes in achieving body weight and body composition targets. Carbohydrate loading strategies and within exercise carbohydrate intake should reflect the specific requirements of the triathlon event contested. Development of an individualised fluid plan based on previous fluid balance observations may assist to avoid both dehydration and hyponatremia during prolonged triathlon racing.
This study was performed to determine the relationship between increased fat oxidation and decreased running efficiency following intense cycling exercise.
Twenty-two middle-level triathletes were studied during submaximal running before and after submaximal cycling exercise. All subjects completed a 13-min run on a track at a velocity corresponding to 75% of their maximal aerobic speed (MAS) before (T1) and after (T2) submaximal cycling exercise at 75 % of maximal aerobic power (MAP). The energy cost of running (Cr) was quantified using the O(2) uptake (.VO(2)) and energy expenditure (EE) using the respiratory exchange ratio (RER). Gas exchange was measured over 30 s during the 3(rd) min and last 30 s of each run.
The results show that after cardiorespiratory equilibration (12 min 30 s), Cr (calculated in mL(O(2))*kg(-1)*m(-1)) during T2 was higher than during T1 (+ 8.2+/-4.3%; P = 0.03). Similar observations were made for .VO(2) (+ 8.2+/-4.3%; P = 0.03) and pulmonary ventilation (+ 7.0+/-12.3%; P = 0.04). RER decreased between T1 and T2 (- 8.6+/-9.2 %; p = 0.01). EE and Cr expressed in kJ.kg(-1).m(-1) did not vary significantly between T1 and T2.
We suggest that the decrease in RER drop may be a result of greater lipid oxidation as metabolic substrate after cycling exercise.
Adaptive gaits of humans were produced as a result of emergent properties of a model based on the neurophysiology of the central pattern generator and the biomechanics of the human musculoskeletal system. We previously proposed a neuromusculoskeletal model for human locomotion, in which movements emerged as a stable limit cycle that was generated through the global entrainment among the neural system, composed of neural oscillators, the musculoskeletal system, and the environment. In the present study, we investigated the adaptability of this model under various types of environmental and task constraints. Using a computer simulation, it was found that walking movements were robust against mechanical perturbations, loads with a mass, and uneven terrain. Moreover, the speed of walking could be controlled by a single parameter which tonically drove the neural oscillators, and the step cycle could be entrained by a rhythmic input to the neural oscillators.
A new principle of sensorimotor control of legged locomotion in an unpredictable environment is proposed on the basis of neurophysiological knowledge and a theory of nonlinear dynamics. Stable and flexible locomotion is realized as a global limit cycle generated by a global entrainment between the rhythmic activities of a nervous system composed of coupled neural oscillators and the rhythmic movements of a musculo-skeletal system including interaction with its environment. Coordinated movements are generated not by slaving to an explicit representation of the precise trajectories of the movement of each part but by dynamic interactions among the nervous system, the musculo-skeletal system and the environment. The performance of a bipedal model based on the above principle was investigated by computer simulation. Walking movements stable to mechanical perturbations and to environmental changes were obtained. Moreover, the model generated not only the walking movement but also the running movement by changing a single parameter nonspecific to the movement. The transitions between the gait patterns occurred with hysteresis.
In this study of human locomotion we investigate to what extent the normal frequency and amplitude of leg movements can be modified voluntarily at different constant velocities, and how these modifications are accomplished in terms of changes in duration and length of the support and swing phases of the stride cycle. Eight healthy male subjects performed walking and running on a motor-driven treadmill at speeds ranging from 1.0 to 3.0 m s-1 (walking) and 1.5 to 8.0 m s-1 (running), respectively. At each speed the subjects walked and ran with: normal stride frequency; the highest possible stride frequency, and the lowest possible stride frequency. Time for foot contact was measured with a special pressure transducer system under the sole of each shoe. At all speeds of walking and running it was possible to either increase or decrease the frequency of leg movements; that is, to decrease or increase stride cycle duration. The range of variation decreased with increasing speed. The mean overall stride frequency range was 0.41 (low frequency walk 1.0 m s-1)-3.57 Hz (high-frequency run 1.5 m s-1). Stride length ranged 0.40 (high frequency walk 1.0 m s-1)-5.00 m (low frequency run 6.0 m s-1). At normal frequency the overall ranges of stride frequency and length were 0.83-1.95 Hz and 1.16-4.10 m, respectively. The stride frequency increased with speed in low frequency walking and running (as in normal frequency) and decreased in high frequency, despite the effort to maintain extreme frequencies. Only in high frequency walking could the stride frequency be kept approximately constant.(ABSTRACT TRUNCATED AT 250 WORDS)
The aim of this study was to investigate the increase in energy cost of running occurring at the end of a triathlon and a marathon event and to link them to the metabolic and hormonal changes, as well as to variations in stride length. Seven subjects took part in 3 experimental situations: a 2 h 15 min triathlon (30 min swimming, 60 min cycling and 45 min running), a 2 h 15 min marathon (MR) were the last 45 min were run at the same speed as the triathlon run (TR), and a 45 min isolated run (IR) done at triathlon speed. The results show that energy cost during MR was higher than during TR (p < 0.01) (+ 8.9%). Similar observations were made for pulmonary ventilation (+ 7.9%) and heart rate (+ 6.3%). Moreover, the values were significantly greater than the values obtained during the IR. TR and MR lead to greater weight loss (p < 0.01) (2.4 +/- 0.3 kg) than IR (1 +/- 0.2 kg). The triathlon and the marathon produced a large decrease in plasma volume (respectively 19.6 +/- 1.4% and 12.9 +/- 1.1%) compared to IR (2 +/- 0.4%). Plasma renin activity was higher for the triathlon and the marathon than for the IR (p < 0.01). MR produces a significantly greater increase in plasma free fatty acids (F.F.A.) than TR (p < 0.05) and IR (p < 0.01). In addition, the F.F.A. at the end of TR were significantly higher than IR (p < 0.05). At the end of the trial the mean stride lengths for TR and IR were greater (+ 15%) (p < 0.01) than for MR. This study, carried out with subjects running overground, confirms the decrease in running efficiency previously shown at the end of a laboratory triathlon, and demonstrates that this decrease is lower than that occurring during a marathon.
The purpose of the present study was to check the increase in energy cost of running at the end of a triathlon and a marathon and to link the decrease in energy cost of running with running kinematic parameters. Seven well-trained triathletes performed 3 experimental trials: a 2 h 15 min triathlon (30 min swimming, 60 min cycling and 45 min treadmill running), a 2 h 15 min marathon where the last 45 min (MR) were run at the same speed as the triathlon run (TR) (i.e. 75% of maximal aerobic speed), and a 45 min isolated run (IR) done at the same speed. Oxygen uptake (VO2), minute ventilation (VE), heart rate (HR), respiratory exchange ratio (RER) and kinematic data were recorded during the 3 exercise runs. The results confirm a higher energy cost during MR compared with TR (+ 3.2%; p <0.05) and IR (+ 11.7%; p <0.01). The triathlon and the marathon were associated with greater weight loss (1.6 +/- 0.02 kg; p <0.01) than the isolated run (0.7 +/- 0.2 kg). After cycling, the mean stride length in TR1 was lower during IR1 and increased at the end of TR. The results show that MR led to decrease in stride length compared with IR. After cycling, the triathletes adopted a more forward leaning posture and the trunk gradient was less marked during the marathon. Moreover, the extension of the knee at foot-strike and the maximal knee angle in non-support phase both increased during MR compared with TR and IR. However, it appears that no single kinematic variable can fully explain the decrease in running efficiency: it seems that running economy during a triathlon and a marathon are linked to global alterations of many different parameters.
We attempted to elicit automatic stepping in healthy humans using appropriate afferent stimulation. It was found that continuous leg muscle vibration produced rhythmic locomotor-like stepping movements of the suspended leg, persisting up to the end of stimulation and sometimes outlasting it by a few cycles. Air-stepping elicited by vibration did not differ from the intentional stepping under the same conditions, and involved movements in hip and knee joints with reciprocal electromyogram (EMG) bursts in corresponding flexor and extensor muscles. The phase shift between evoked hip and knee movements could be positive or negative, corresponding to 'backward' or 'forward' locomotion. Such an essential feature of natural human locomotion as alternating movements of two legs, was also present in vibratory-evoked leg movements under appropriate conditions. It is suggested that vibration evokes locomotor-like movements because vibratory-induced afferent input sets into active state the central structures responsible for stepping generation.