Running Leg Research Articles

Race Dynamics in Triathlon Mixed-Team-Relay Meaningfully Changes with The New Regulation Towards Paris 2024.

Mixed-Team-Relay (MTR) triathlon is a novel Olympic discipline whose performance determinants and tactical behaviors have barely been studied. Additionally, a regulatory change has been made to the male and female relay order for the Paris 2024 Olympics. Therefore, this study aimed to determine the performance determinants and race dynamics as a function of competitive level on the new regulated MTR triathlon. Results from 129 national teams, (516 elite triathletes) across five MTR World Triathlon Series and two MTR European Championships in 2022 and 2023, were analyzed. Split times, average speeds, time behind the race leader (gap), partial and finishing positions, pack position as well as the rank positions of every segment, relay leg, and overall race were computed. Decision tree analyses were conducted as a predictive method for the overall results, and correspondence analyses were conducted to examine the relationship between the different relay legs and segments and the finishing positions. The performance of the fourth leg was the most relevant for overall result (30%), as well as the fourth running leg (16%) and the female legs performance (7%). Medallist relay teams were characterized by displaying a differential speed lower than 0.5 and 0.83 km/h, respectively, from the best-ranking athletes in the Legs 1 and 4. Furthermore, staying in the front pack after the second swimming leg showed a great relationship with achieving a medal position. New MTR triathlon rules shift race dynamics, emphasizing individual efforts in cycling and swimming, while maintaining the crucial importance of running.

Equivalent running leg lengths require prosthetic legs to be longer than biological legs during standing

We aimed to determine a method for prescribing a standing prosthetic leg length (ProsL) that results in an equivalent running biological leg length (BioL) for athletes with unilateral (UTTA) and bilateral transtibial amputations (BTTA). We measured standing leg length of ten non-amputee (NA) athletes, ten athletes with UTTA, and five athletes with BTTA. All athletes performed treadmill running trials from 3 m/s to their maximum speed. We calculated standing and running BioL and ProsL lengths and assessed the running-to-standing leg length ratio (Lratio) at three instances during ground contact: touchdown, mid-stance, and take-off. Athletes with UTTA had 2.4 cm longer standing ProsL than BioL length (p = 0.030), but their ProsL length were up to 3.3 cm shorter at touchdown and 4.1 cm shorter at mid-stance than BioL, at 3–11.5 m/s. At touchdown, mid-stance, and take-off, athletes with BTTA had 0.01–0.05 lower Lratio at 3 m/s (p < 0.001) and 0.03–0.07 lower Lratio at 10 m/s (p < 0.001) in their ProsL compared to the BioL of NA athletes. During running, ProsL were consistently shorter than BioL. To achieve equivalent running leg lengths at touchdown and take-off, athletes with UTTA should set their running-specific prosthesis height so that their standing ProsL length is 2.8–4.5% longer than their BioL length, and athletes with BTTA should set their running-specific prosthesis height so that their standing ProsL lengths are at least 2.1–3.9% longer than their presumed BioL length. Setting ProsL length to match presumed biological dimensions during standing results in shorter legs during running.

The effects of simulated duathlon on multisegment running external and internal load in well-trained triathletes

ABSTRACT Duathlon is a rapidly promoting sport, so it is necessary to identify the factors that influence performance. This study aimed to analyse internal and external loads and the interactions between them during running legs before and after cycling in duathlon. Twenty-three male and female athletes participated in a simulated duathlon (5k-20k-5k). Internal workload was assessed using the rate of perceived exertion (RPE) and heart rate (maximum: HRMAX; average: HRAVG; R-R interval), whereas external workload was assessed using inertial sensors (Player Load by RealTrack, PLRT) attached to six body locations. The results showed that both running legs presented an increasing trend in RPE, HRMAX, and HRAVG throughout the kilometres, while the R–R interval decreased. The PLRT of the upper and lower back, knee, and ankle increased throughout the first running leg but not in the second. The PLRT was greater in the lower body than in the upper body because of energy absorption. RPE was higher in the second running leg than in the first leg. In conclusion, the cycling leg affects the internal and external load between running legs in duathlon. Load monitoring can help coaches understand duathletes’ performance and design specific training strategies to reduce fatigue during competition.

A Study of Race Pacing in the Running Leg of the Japan University Triathlon Championship.

Choosing an appropriate pacing strategy is important for good triathlon performance. In the Japan Student Triathlon Championship held in 2020, the men's category was divided into two groups, which was a different racing style from the previous races that all athletes start at the same time. It is highly likely that the performance level will vary as grouping was performed according to the competence of each player. The aim of this study was to understand the relationship of the total time and time of each leg between the superior performance group and the inferior performance group, as well as the difference in pacing during running in participants of the 2020 Japan University Triathlon Championship Watarase Competition, which was held under unconventional conditions. We analyzed 153 male athletes (Group A: 77; Group B: 76) who completed the race. The total race time, leg time, and average speed in each leg and its variation coefficient were evaluated based on the official results of the competition and footage recorded during the race. The results showed that the total time and leg time for each leg were significantly shorter in Group A compared to those in Group B (p < 0.05). In both groups, the Lap 4 run was significantly slower than those of Laps 1–3 (p < 0.05), while there was no significant difference in the running speed to average speed ratio across all laps between the groups (p < 0.05). Thus, there was a difference in running speed between the groups, but no significant difference in pacing. The results of this study serve as basic data for examining superior pacing strategies, although further studies on a wide range of competition levels are necessary.

Exercise Intensity during Olympic-Distance Triathlon in Well-Trained Age-Group Athletes: An Observational Study

The aim of this study was to examine the exercise intensity during the swimming, cycling, and running legs of nondraft legal, Olympic-distance triathlons in well-trained, age-group triathletes. Seventeen male triathletes completed incremental swimming, cycling, and running tests to exhaustion. Heart rate (HR) and workload corresponding to aerobic and anaerobic thresholds, maximal workloads, and maximal HR (HRmax) in each exercise mode were analyzed. HR and workload were monitored throughout the race. The intensity distributions in three HR zones for each discipline and five workload zones in cycling and running were quantified. The subjects were then assigned to a fast or slow group based on the total race time (range, 2 h 07 min–2 h 41 min). The mean percentages of HRmax in the swimming, cycling, and running legs were 89.8% ± 3.7%, 91.1% ± 4.4%, and 90.7% ± 5.1%, respectively, for all participants. The mean percentage of HRmax and intensity distributions during the swimming and cycling legs were similar between groups. In the running leg, the faster group spent relatively more time above HR at anaerobic threshold (AnT) and between workload at AnT and maximal workload. In conclusion, well-trained male triathletes performed at very high intensity throughout a nondraft legal, Olympic-distance triathlon race, and sustaining higher intensity during running might play a role in the success of these athletes.

SEX AND AGE-RELATED CHANGES IN PERFORMANCE IN THE DUATHLON WORLD CHAMPIONSHIPS

ABSTRACT Objective Our study analyses differences in performance between sexes, and changes in performance between age groups at Olympic distance during the ITU Duathlon World Championships, held between 2005 and 2016. During this period, a total of 9,772 duathletes were analysed (6,739 men and 3,033 women). Methods Two-way analyses of variance (ANOVA) were used to examine sex- and age-related differences in performance (time, percentage of time and performance ratio) in the first running and cycling legs, the second running leg, and total race for the top 10 male and female athletes in each age group at the Duathlon World Championships. Results The age group with the highest participation, in both male and female categories, was 40-44 years, and it was found that the mean age of female finisher participants across all age groups was 23.5±12. With regards to performance, the best results for total race time and the cycling segment were achieved in the 30-34-year age group, for both male and female athletes. With regards to performance in the first and third segments (running legs), the best times were achieved in the 25-29 and 30-34 age groups, for men and women respectively. Conclusion According to the results of our study, the best results in the professional career of a duathlete are achieved at between 30 and 35 years, therefore the athlete should incorporate this factor into their training plan. Level of evidence III; Retrospective comparative study.

A comparison and update of direct kinematic-kinetic models of leg stiffness in human running

Direct kinematic-kinetic modelling currently represents the “Gold-standard” in leg stiffness quantification during three-dimensional (3D) motion capture experiments. However, the medial-lateral components of ground reaction force and leg length have been neglected in current leg stiffness formulations. It is unknown if accounting for all 3D would alter healthy biologic estimates of leg stiffness, compared to present direct modelling methods. This study compared running leg stiffness derived from a new method (multiplanar method) which includes all three Cartesian axes, against current methods which either only include the vertical axis (line method) or only the plane of progression (uniplanar method). Twenty healthy female runners performed shod overground running at 5.0 m/s. Three-dimensional motion capture and synchronised in-ground force plates were used to track the change in length of the leg vector (hip joint centre to centre of pressure) and resultant projected ground reaction force. Leg stiffness was expressed as dimensionless units, as a percentage of an individual’s bodyweight divided by standing leg length (BW/LL). Leg stiffness using the line method was larger than the uniplanar method by 15.6%BW/LL (P < .001), and multiplanar method by 24.2%BW/LL (P < .001). Leg stiffness from the uniplanar method was larger than the multiplanar method by 8.5%BW/LL (6.5 kN/m) (P < .001). The inclusion of medial-lateral components significantly increased leg deformation magnitude, accounting for the reduction in leg stiffness estimate with the multiplanar method. Given that limb movements typically occur in 3D, the new multiplanar method provides the most complete accounting of all force and length components in leg stiffness calculation.

Shortness Of Breath - Triathlon

HISTORY: A 50-year-old female triathlete with a history of hypertension and asthma was referred to our clinic for exercise-induced bronchoconstriction testing. She reported an 8 year history of episodes of dyspnea and cough that come on while competing in the swimming leg of the triathlon and continue through the rest of the race. Symptoms generally resolve within 24 hours. They do not occur with every race. They have never occurred during training. Onset of symptoms has never occurred during the bike or running leg. She was diagnosed with asthma 3 years prior and has been using albuterol prior to exercise as well as Advair as a controller agent since then, with no change in frequency of episodes. PHYSICAL EXAMINATION: Well-appearing, no acute distress. Neck without carotid bruits. Lungs clear bilaterally, no wheezes, rales, or rhonchi. CV normal S1 and S2, regular, with no murmurs, rubs, or gallops. No peripheral edema. Peripheral pulses 2+ DIFFERENTIAL DIAGNOSIS:Swimming-induced pulmonary edema, asthma, exercise-induced bronchoconstriction, vocal cord dysfunction, cardiogenic pulmonary edema, coronary artery disease TEST AND RESULTS: Spirometry pre- and post-exercise were performed with no evidence of obstructive lung disease and no decrease in FEV1 post-exercise. Exercise stress echo was also performed, which showed normal cardiac function and no evidence of exercise-induced ischemia. The patient had a markedly hypertensive response to exercise. Post-exercise PA systolic pressure was estimated at 65–75 mm Hg. FINAL WORKING DIAGNOSIS: Swimming-induced pulmonary edema in the setting of hypertension TREATMENT AND OUTCOMES: The patient was evaluated by cardiology. Hypertension was treated. She had not experienced any symptoms during her last few races.

The Annotated Poe

The Annotated Poe

The Annotated Poe

The Annotated Poe

Sprint running: how changes in step frequency affect running mechanics and leg spring behaviour at maximal speed

ABSTRACTThe purpose of this study was to investigate the changes in selected biomechanical variables in 80-m maximal sprint runs while imposing changes in step frequency (SF) and to investigate if these adaptations differ based on gender and training level. A total of 40 athletes (10 elite men and 10 women, 10 intermediate men and 10 women) participated in this study; they were requested to perform 5 trials at maximal running speed (RS): at the self-selected frequency (SFs) and at SF ±15% and ±30%SFs. Contact time (CT) and flight time (FT) as well as step length (SL) decreased with increasing SF, while kvert increased with it. At SFs, kleg was the lowest (a 20% decrease at ±30%SFs), while RS was the largest (a 12% decrease at ±30%SFs). Only small changes (1.5%) in maximal vertical force (Fmax) were observed as a function of SF, but maximum leg spring compression (ΔL) was largest at SFs and decreased by about 25% at ±30%SFs. Significant differences in Fmax, Δy, kleg and kvert were observed as a function of skill and gender (P < 0.001). Our results indicate that RS is optimised at SFs and that, while kvert follows the changes in SF, kleg is lowest at SFs.

Numerical investigation on trimming of a single sail in a regatta

In sailing regattas, the actions of sailboats are to meet, overlap, pursue, pass, anti-collide, and defend. The aerodynamic performance of a sail based on a numerical simulation method is reported in this study. The parameters affecting the sail’s aerodynamic force coefficients, namely sailing angle, attack angle, mast shape, pitch angle, and camber ratio, are analyzed. From the results, basic principles and corresponding tactics of sail trimming are discussed and recommended for the start, during the windward, running, and leeward legs, before the finish, and near the marks. Sailors in the regatta should decrease the interaction of air flows around the sail to increase the lift force. The sailing angle, attack angle, pitch angle, and camber ratio should be adjusted to the appropriate degree to speed the boat when it is balanced. Sail trimming tactics have been practiced by professional sailors in regattas during which they can be scientifically supervised to compete against each other at Olympic Games.

달리기 시 체간의 골반-척추구조변형이 동적안정성에 미치는 연구

The purposes of this study were to assess dynamic stability toward pelvis-spine column distortion during running and to compare the typical three-dimensional angular kinematics of the trunk motion; cervical, thoracic, lumbar segment spine and the pelvis from the multi-segmental spine model between exercise group and non-exercise group. Subjects were recruited as exercise healthy women on regular basis (group A, n=10) and non-exercise idiopathic scoliosis women (group B, n=10). Data was collected by using a vicon motion capture system (MX-T40, UK). The pelvis, spine segments column and lower limbs analysiaed through the 3D kinematic angular ROM pattern. There were significant differences in the time-space variables, the rotation motion of knee joint in lower limbs and the pelvis variables; obliquity in side bending, inter/outer rotation in twisting during running leg movement. There were significant differences in the spinal column that is lower-lumbar, upper-lumbar, upper-thoracic, mid-upper thoracic, mid-lower thoracic, lower thoracic and cervical spine at inclination, lateral bending and twist rotation between group A and group B (<.05, <.01 and <.001). As a results, group B had more restrictive motion than group A in the spinal column and leg movement behaved like a 'shock absorber". And the number of asymmetry index (AI) showed that group B was much lager unbalance than group A. In conclusion, non-exercise group was known to much more influence the dynamic stability of equilibrium for bilateral balance. These finding suggested that dynamic stability aimed at increasing balance of the trunk ROM must involve methods and strategies intended to reduce left/right asymmetry and the exercise injury.

Wheat gluten hydrolysate affects race performance in the triathlon

Wheat gluten hydrolysate (WGH) is a food ingredient, prepared by partial enzymatic digestion of wheat gluten, which has been reported to suppress exercise-induced elevation of serum creatinine kinase (CK) activity. However, its effects on athletic performance have not yet been elucidated. This is the presentation of an experiment performed on five female college triathletes who completed an Olympic distance triathlon with or without ingestion of 21 g of WGH during the cycling leg. The experiment was performed in a crossover double-blind manner. The race time of the running leg and thus the total race time was significantly shorter when WGH was ingested. However, serum CK levels exhibited no apparent differences between the two WGH or placebo groups.

Evolution of Vertebrate Limb Morphology

The vertebrate limb is an extraordinarily flexible structure that has evolved to accomplish a wide range of tasks in different taxa, from the grasping human hand, to the wing of the bat, the digging limb of the mole or the running leg of the horse. To understand the developmental basis for such diversity, we are focusing on the diverged morphology of the hindlimbs of jerboas, bipedal Asian rodents closely related to mice. These hindlimbs show a number of derived characteristics, including greatly increased size, altered allometric growth of individual elements (such as the metatarsals which are extended to a length similar to that of the femur or tibia); fusion of elements, and reduction in number of digits. We have found that changes in relative growth of the skeletal elements are achieved, to a large extent, by modulating the size of the individual hypertrophic cells in the developing growth plate, a multi‐phasic process involving cell swelling as well as proportional cell growth. It is the final phase of proportional mass increase, an IGF1‐dependent step, that appears to be modulated evolutionarily as skeletal element size is varied. Decrease in digit number has also been investigated in these animals. The normal set of five digit primordia appear to be specified in the jerboa hindlimbs as they are in the mouse. However, the lateral digits are lost through an expansion of cell death, regulated by Msx2 and Bmp4. A similar mechanism appears to have been used in the evolution of the single central digit of the horse.

Biomechanics of human bipedal gallop: asymmetry dictates leg functions

Unilateral skipping or bipedal galloping is one of the gait types that humans are able to perform. In contrast to many animals, where gallop is the preferred gait at higher speeds, human bipedal gallop only occurs spontaneously in very specific conditions (e.g. fast downhill locomotion). This study examines the lower limb mechanics and explores the possible reasons why humans do not spontaneously opt for gallop for steady-state locomotion on level ground. In 12 subjects, who were required to run and gallop overground at their preferred speed, kinematic and kinetic data were collected and mechanical work at the main lower limb joints (hip, knee, ankle) was calculated. In a separate treadmill experiment, metabolic costs were measured. Analysis revealed that the principal differences between running and galloping are located at the hip. The asymmetrical configuration of gallop involves distinct hip actions and foot placing, giving galloping legs different functions compared with running legs: the trailing leg decelerates the body in the vertical direction but propels it forward while the leading leg acts in the opposite way. Although both legs conserve mechanical energy by interchanging external mechanical energy with potential elastic energy, the specific orientation of the legs causes more energy dissipation and generation compared with running. This makes gallop metabolically more expensive and involves high muscular stress at the hips, which may be why humans do not use gallop for steady-state locomotion.

Physiological demand and pacing strategy during the new combined event in elite pentathletes

To evaluate the physiological demands and effects of different pacing strategies on performance during the new combined event (CE) of the modern pentathlon (consisting of three pistol shooting sessions interspersed by three 1-km running legs). Nine elite pentathletes realised five tests: a free-paced CE during an international competition; an incremental running test to determine [Formula: see text] and its related velocity ([Formula: see text]) and three experimental time-trial CE, where the pacing strategy was manipulated (CE(ref), CE(100%), CE(105%)). CE(ref) reproduced the international competition strategy with a 170-m fast running start within the first 2 km. CE(100%) and CE(105%) imposed a constant strategy over km-1 and km-2 with a velocity of 100 and 105% of the mean speed adopted over the same sections during the international competition, respectively. Km-3 was always self-paced. The subjects ran CE(ref) at 99 ± 4% of [Formula: see text] and reached 100 ± 5, 100 ± 7, 99 ± 8% of [Formula: see text] at the end of kilometres 1, 2 and 3, respectively ([Formula: see text]: 72 ± 6 mL O(2) min(-1) kg(-1)), with a peak blood lactate concentration of 13.6 ± 1.5 mmol L(-1). No significant differences in overall performance were found between the pacing conditions (753 ± 30, 770 ± 39, 768 ± 27 s for CE(ref), CE(100%) and CE(105%), respectively, p = 0.63), but all of the shooting performance parameters were only stable in CE(ref). Completion of CE by elite pentathletes elicits a maximal aerobic contribution coupled with a high glycolytic supply. Manipulating the mean running speed over km-1 and km-2 had strong influence on the overall pacing strategy and induced minor differences in shooting performance, but it did not affect overall performance.

Influence of gender on pacing adopted by elite triathletes during a competition

The aim of this study was to compare the pacing strategies adopted by women and men during a World Cup ITU triathlon. Twelve elite triathletes (6 females, 6 males) competed in a World Cup Olympic distance competition where speed and heart rate (HR) were measured in the three events. The power output (PO) was recorded in cycling to determine the time spent in five intensity zones ([0-10% VT1]; [10% VT1-VT1]; [VT1-VT2]; [VT2-MAP] and > or =MAP) [ventilatory threshold (VT); maximal aerobic power (MAP)]. Swimming and running speeds decreased similarly for both genders (P < 0.05) and HR values were similar through the whole race (92 +/- 2 and 92 +/- 3% of maximal HR for women and men, respectively). The distribution of time spent in the five zones during the cycling leg was the same for both genders. The men's speed and PO decreased after the first bike lap (P < 0.05) and the women spent relatively more time above MAP in the hilly sections (45 +/- 4 vs. 32 +/- 4%). The men's running speed decreased significantly over the whole circuit, whereas the women slowed only over the uphill and downhill sections (P < 0.05). This study indicates that both female and male elite triathletes adopted similar positive pacing strategies during swimming and running legs. Men pushed the pace harder during the swim-to-cycle transition contrary to the women and female triathletes were more affected by changes in slope during the cycling and running phases.

Strategies for Improving Performance in Long Duration Events

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.

Running against the wind [sports prosthetics

This paper discusses the implications of recent technological advances in sports prosthetics on the existing rules for various sporting events. The paper points to the record-breaking performance of the double-leg amputee from South Africa, Oscar Pistorius, at the 2004 Paralympic Games in Athens. Fitted with high-tech carbon-fiber artificial running legs, Pistorius became the first leg amputee to run the 200-meter dash in less than 22 seconds. Because it seems likely that Pistorius will one day qualify for able-bodied competitions, current rules may need to be reviewed.