Race Speed Research Articles

Development and Validation of Prediction Equation of "Athens Authentic Marathon" Men's Race Speed.

AimDespite the increasing popularity of outdoor endurance running races of different distances, little information exists about the role of training and physiological characteristics of recreational runners. The aim of the present study was (a) to examine the role of training and physiological characteristics on the performance of recreational marathon runners and (b) to develop a prediction equation of men’s race time in the “Athens Authentic Marathon.”MethodsRecreational male marathon runners (n = 130, age 44.1 ± 8.6 years)—who finished the “Athens Authentic Marathon” 2017—performed a series of anthropometry and physical fitness tests including body mass index (BMI), body fat percentage (BF), maximal oxygen uptake (VO2max), anaerobic power, squat, and countermovement jump. The variation of these characteristics was examined by quintiles (i.e., five groups consisting of 26 participants in each) of the race speed. An experimental group (EXP, n = 65) was used to develop a prediction equation of the race time, which was verified in a control group (CON, n = 65).ResultsIn the overall sample, a one-way ANOVA showed a main effect of quintiles on race speed on weekly training days and distance, age, body weight, BMI, BF, and VO2max (p ≤ 0.003, η2 ≥ 0.121), where the faster groups outscored the slower groups. Running speed during the race correlated moderately with age (r = −0.36, p < 0.001) and largely with the number of weekly training days (r = 0.52, p < 0.001) and weekly running distance (r = 0.58, p < 0.001), but not with the number of previously finished marathons (r = 0.08, p = 0.369). With regard to physiological characteristics, running speed correlated largely with body mass (r = −0.52, p < 0.001), BMI (r = −0.60, p < 0.001), BF (r = −0.65, p < 0.001), VO2max (r = 0.67, p < 0.001), moderately with isometric muscle strength (r = 0.42, p < 0.001), and small with anaerobic muscle power (r = 0.20, p = 0.021). In EXP, race speed could be predicted (R2 = 0.61, standard error of the estimate = 1.19) using the formula “8.804 + 0.111 × VO2max + 0.029 × weekly training distance in km −0.218 × BMI.” Applying this equation in CON, no bias was observed (difference between observed and predicted value 0.12 ± 1.09 km/h, 95% confidence intervals −0.15, 0.40, p = 0.122).ConclusionThese findings highlighted the role of aerobic capacity, training, and body mass status for the performance of recreational male runners in a marathon race. The findings would be of great practical importance for coaches and trainers to predict the average marathon race time in a specific group of runners.

The Impact of Blade Technology on Paralympic Sprint Performance Between 1996 and 2016: Bilateral Amputees' Competitive Advantage.

It is known that high-performance sprinters with unilateral and bilateral prosthetic lower limbs run at different speeds using different spatiotemporal strategies. Historically, these athletes still competed together in the same races, but 2018 classification rule revisions saw the separation of these two groups. This study sought to compare Paralympic sprint performance between all-comer (i.e., transfemoral and transtibial) unilateral and bilateral amputee sprinters using a large athlete sample. A retrospective analysis of race speed among Paralympic sprinters between 1996 and 2016 was conducted. In total, 584 published race results from 161 sprinters revealed that unilateral and bilateral lower-extremity amputee sprinters had significantly different race speeds in all three race finals (100m, p value <.001; 200m, <.001; 400m, <.001). All-comer bilateral amputee runners ran faster than their unilateral counterparts; performance differences increased with race distance. These data support current classification criteria in amputee sprinting, which may create more equal competitive fields in the future.

Risk factors for not finishing an ultramarathon: 4-year study in 23,996 race starters, SAFER XXI.

Limited data support prerace medical screening to identify risk factors for not finishing an endurance running race. The aim of the study was to determine risk factors associated with not finishing an ultramarathon. A prospective, cross-sectional study of Two Oceans ultramarathon (56 km) race starters who completed a prerace medical screening questionnaire. Race day environmental conditions were recorded on race day. Univariate analyses of risk factors associated with the did-not-finish (DNF) included race day factors and prerace medical screening history. Risk factors for DNF amongst 23,996 starters during the 56 km race included older age and females (P<0.0001). After adjusting for age and sex, the following were significant univariate risk factors: fewer years of running (P<0.0001), less previous race experience (P<0.0001), less training/racing per week (P=0.0002), lower average weekly training distance (P=0.0016), slower race vs. training speed (P<0.0001), lack of allergies (P=0.0100) and average wet-bulb globe temperature (P<0.0001). Females, older age, training-related factors (less training/racing, average weekly training distance, race vs. training speed) and average wet-bulb temperature, were risk factors for not finishing an ultramarathon. The results may not only assist runners and coaches in race preparation, but also have clinical implications for the medical planning prior to races.

Pacing in Time-Limited Ultramarathons from 6 to 24 Hours—The Aspects of Age, Sex and Performance Level

(1) Background: Compared with marathon races, pacing in time-limited ultramarathons has only been poorly discussed in the literature. The aim of the present study was to analyze the interaction of performance level, age and sex with pacing during 6 h, 12 h or 24 h time-limited ultramarathons. (2) Methods: Participants (n = 937, age 48.62 ± 11.80 years) were the finishers in 6 h (n = 40, 17 women and 23 men), 12 h (n = 232, 77 women and 155 men) and 24 h (n = 665, 166 women and 409 men) ultramarathons. The coefficient of variation (CV), calculated as SD/mean, was used to described pacing. Low scores of CV denoted a more even pacing, and vice versa. A two-way analysis of variance examined the main effects and interactions of sex and race duration on age, race speed and pacing. (3) Results: More men participated in the longer race distances than in the shorter ones and men were older and faster than women. Comparing the 6 h, 12 h and 24 h races, the finishers in the 6 h were the fastest, the finishers in the 12 h were the oldest and the finishers in the 24 h showed the most variable pacing. Furthermore, the faster running speed in the 12 h (women, r = −0.64; men, r = −0.49, p &lt; 0.001) and the 24 h (r = −0.47 in women and men, p &lt; 0.001) was related to less variable pacing. (4) Conclusions: These data might help runners and coaches to choose the the proper duration of a race and training programs for their athletes.

Comparisons of Macro-Kinematic Strategies During the Rounds of a Cross-Country Skiing Sprint Competition in Classic Technique.

This study was designed to examine macro-kinematic parameters of six female cross-country skiers during the qualifying, semi-final and final rounds of a 1.1 km sprint competition in classical technique. During each round these skiers were monitored continuously with a single micro-sensor, and their cycle parameters and relative use of these two sub-techniques calculated. Within each round six sections of the course, during which all skiers employed either double pole (DP) or diagonal stride (DS) sub-technique, were chosen for additional analysis. The mean macro-kinematic cycle parameters and relative usage of sub-techniques over the full course did not differ significantly between rounds. On average 54% of the course was covered employing DP and 13% using DS, while 32% was covered utilizing a non-cyclical or irregular technique. With DP, the mean racing speed and cycle rate (CR) on the starting, middle and finishing sections of the course differed significantly, with no differences in mean cycle length (CL) between the last two sections. At the finish, higher DP speed was achieved by increasing CR. On the three hills, where all athletes utilized DS, mean racing speed and CL, but not mean CR, differed significantly. On these sections DS speed was increased by utilizing longer cycles. The individual skiers utilized a variety of macro-kinematic strategies during different rounds and on different sections of the course, depending on individual strengths, preferences and pacing strategies, as well as the course topography and tactical interactions with other skiers. Such collection of macro-kinematic data during competitions can help to identify an individual skier's strengths and weaknesses, guiding the testing of different cycle rates, and lengths on different terrains during training in order to optimize performance.

The effects of race track surface condition on the racing time of Orlov trotters

Race speed is one of the main indicators by which trotting horses are estimated. In addition to the horse genotype, race speed is also determined by the influence of environmental factors, such as feeding, keeping, training, and testing conditions. These conditions include of race track surface condition, the rider’s qualifications, season of the year, weather conditions. In this paper the influence of race track surface condition on the accuracy of assessing race time is considered. The data of horse trials of Orlov trotters at the Moscow hippodrome were used. The race time of 256 horses at a distance of 1600 m was assessed. Depending on the weather conditions and the track surface, 9 different track conditions were identified. For the analysis we used data on stallions and mares aged 4 years and older without disaggregation by sex, since there were no significant differences between the average race speed of stallions and mares and it was shown that it was the horses of the older age group that were reliably characterized by the highest average race time with minimal races per horse. It was found that the strength of the influence of the variety of race tracks on the variety of assessments of race time is reliable and amounted to 23.5%. When analyzing the group of the fastest horses, this indicator turned out to be higher and amounts to 43.8%. It is also shown that the selection of horses for breeding work is more expedient and accurate to carry out according to the average race time of the horse for a number of races, and not according to its best result, since in this case the stability of performances is not taken into account.

“Kumoterki”, tradition, sport and cultural heritage

In the dialect of Polish Tatra highlanders the word “kumoterki” indicates a small two-person sleigh traditionally harnessed to one horse. It is derived from the word “kumotrzy” which is godparents who used the horse team to get with a newborn baby to church to have the child baptised.Since the mid-19th-century horse-drawn sleighs used by Tatra highlanders have been the masterpieces of woodcarving art. A lot of attention has been paid to the precision of workmanship, the choice of material and ornamentation. Initially, they were used as the means of transport during snowy winters in the Polish Tatra region. During the Interwar period, due to the development of mass motorization, horse-drawn sleighs lost their utilitarian character and people started to use them in racing events. The first horse-drawn sleigh race took place in Zakopane in 1929. It was an annual event until 1939. After World War 2, horse-drawn sleigh races were reactivated in 1962 in Zakopane and after that, after a few-year break, in 1972 in Bukowina Tatrzańska.In the 1970s horse-drawn sleigh races were treated mostly as social events and folk festivities rather than sports competitions. Horses that took part in the races at that time were used to work mainly on the farmland and were not specially prepared for the races. This situation changed completely at the beginning of the 1990s after sport horses had been brought to Podhale. Since then horse-drawn sleigh races have become typical sports competitions; older highlanders started to resign from speed racing leaving the place for young contestants. Sports rivalry and willingness to achieve the best time of a ride displaced the fun and entertainment factor of this event.

Cluster analysis of impairment measures to inform an evidence-based classification structure in RaceRunning, a new World Para Athletics event for athletes with hypertonia, ataxia or athetosis

ABSTRACT RaceRunning enables athletes with limited or no walking ability to propel themselves independently using a three-wheeled frame that has a saddle, handle bars and a chest plate. For RaceRunning to be included as a para athletics event, an evidence-based classification system is required. This study assessed the impact of trunk control and lower limb impairment measures on RaceRunning performance and evaluated whether cluster analysis of these impairment measures produces a valid classification structure for RaceRunning. The Trunk Control Measurement Scale (TCMS), Selective Control Assessment of the Lower Extremity (SCALE), the Australian Spasticity Assessment Scale (ASAS), and knee extension were recorded for 26 RaceRunning athletes. Thirteen male and 13 female athletes aged 24 (SD = 7) years participated. All impairment measures were significantly correlated with performance (rho = 0.55–0.74). Using ASAS, SCALE, TCMS and knee extension as cluster variables in a two-step cluster analysis resulted in two clusters of athletes. Race speed and the impairment measures were significantly different between the clusters (p < 0.001). The findings of this study provide evidence for the utility of the selected impairment measures in an evidence-based classification system for RaceRunning athletes.

Determinants of last lap speed in paced and maximal 1500-m time trials.

The present study identified the physiological and performance characteristics that are deterministic during a maximal 1500-m time trial and in paced 1500-m time trials, with an all-out last lap. Thirty-two trained middle-distance runners (n = 21 male, VO2peak: 72.1 ± 3.2; n = 11, female, VO2peak: 61.2 ± 3.7mL kg-1 min-1) completed a 1500-m time trial in the fastest time possible (1500FAST) as well as a 1500MOD and 1500SLOW trial whereby mean speed was reduced during the 0-1100m by 5% and 10%, respectively. Anaerobic speed reserve (ASR), running economy (RE), the velocity corresponding with VO2peak (VVO2peak), maximal sprint speed (MSS) and maximal accumulated oxygen deficit (MAOD) were determined during additional testing. Carnosine content was quantified by proton magnetic resonance spectroscopy in the gastrocnemius and expressed as a Z-score to estimate muscle fibre typology. 1500FAST time was best explained by RE and VVO2peak in female runners (adjusted r2 = 0.80, P < 0.001), in addition to the 0-1100-m speed relative to VVO2peak in male runners (adjusted r2 = 0.72, P < 0.001). Runners with a higher gastrocnemius carnosine Z-score (i.e., higher estimated percentage of type II fibres) and greater MAOD, reduced their last lap time to a greater extent in the paced 1500-m trials. Neither ASR nor MSS was associated with last lap time in the paced trials. These findings suggest that VVO2 peak and RE are key determinants of 1500-m running performance with a sustained pace from the start, while a higher carnosine Z-score and MAOD are more important for last lap speed in tactical 1500-m races.

Sex-based differences in sub-technique selection during an international classical cross-country skiing competition.

The purpose of this study was to compare speed, sub-technique selection and temporal patterns between world-class male and female cross-country (XC) skiers and to examine the combined associations of sex and speed on sub-technique selection. Thirty-three XC skiers performed an international 10-km (women; n = 8) and 15-km (men; n = 25) time-trial competition in the classical style (with the first 10 km of the race being used for analyses). An integrated GNSS/IMU system was used to continuously track position speed and automatically classify sub-techniques and temporal patterns (i.e. cycle length and–rate). When comparing the eight highest ranked men and women, men spent less time than women (29±2 vs. 45±5% of total time) using diagonal stride (DIA), more time (44±4 vs. 31±4%) using double poling (DP) and more time (23±2 vs. 19±3%) using tucking and turning (all P < .01). Here, men and women used these sub-techniques at similar temporal patterns within the same speed-intervals; although men employed all sub-techniques at steeper uphill gradients (all P < .05). In subsequent analyses including all 33 skiers, adjustment for average racing speed did not fully attenuate the observed sex differences in the proportion of time using DIA (CI95% [-10.7, -1.6]) and DP (CI95% [0.8, 9.3]). Male world-class XC skiers utilized less DIA and more DP compared to women of equal performance levels. Although these differences coincided with men’s higher speed and their ability to use the various sub-techniques at steeper uphill gradients, sexual dimorphism in the proportional use of DIA and DP also occurred independently of these speed-differences.

Aircraft Propellers—Is There a Future?

The race for speed ruled the early Jet Age on aviation. Aircraft manufacturers chased faster and faster planes in a fight for pride and capability. In the early 1970s, dreams were that the future would be supersonic, but fuel economy and unacceptable noise levels made that era never happen. After the 1973 oil crisis, the paradigm changed. The average cruise speed on newly developed aircraft started to decrease in exchange for improvements in many other performance parameters. At the same pace, the airliner’s power-plants are evolving to look more like a ducted turboprop, and less like a pure jet engine as the pursuit for the higher bypass ratios continues. However, since the birth of jet aircraft, the propeller-driven plane has lost its dominant place, associated with the idea that going back to propeller-driven airplanes, and what it represents in terms of modernity and security, has started a propeller avoidance phenomenon with travelers and thus with airlines. Today, even with the modest research effort since the 1980s, advanced propellers are getting efficiencies closer to jet-powered engines at their contemporary typical cruise speeds. This paper gives a brief overview of the performance trends in aviation since the last century. Comparison examples between aircraft designed on different paradigms are presented. The use of propellers as a reborn propulsive device is discussed.

Are humans evolved specialists for running in the heat? Man vs. horse races provide empirical insights.

What is the central question of this study? Do available comparative data provide empirical evidence that humans are adapted to endurance running at high ambient temperatures? What is the main finding and its importance? Comparing the results of races that pit man against horse, we find that ambient temperature on race day has less deleterious effects on running speed in humans than it does on their quadrupedal adversary. This is evidence that humans are adapted for endurance running at high ambient temperatures. We debate whether this supports the hypothesis that early man was evolutionarily adapted for persistence hunting. Many mammals run faster and for longer than humans and have superior cardiovascular physiologies. Yet humans are considered by some scholars to be excellent endurance runners at high ambient temperatures, and in our past to have been persistence hunters capable of running down fleeter quarry over extended periods during the heat of the day. This suggests that human endurance running is less affected by high ambient temperatures than is that of other cursorial ungulates. However, there are no investigations of this hypothesis. We took advantage of longitudinal race results available for three annual events that pit human athletes directly against a hyper-adapted ungulate racer, the thoroughbred horse. Regressing running speed against ambient temperature shows race speed deteriorating with hotter temperatures more slowly in humans than in horses. This is the first direct evidence that human running is less inhibited by high ambient temperatures than that of another endurance species, supporting the argument that we are indeed adapted for high temperature endurance running. Nonetheless, it is far from clear that this capacity is explained by an endurance hunting past because in absolute terms humans are slower than horses and indeed many other ungulate species. While some human populations have persistence hunted (and on occasion still do), the success of this unlikely foraging strategy may be best explained by the application of another adaption - high cognitive capacity. With dedication, experience and discipline, capitalising on their small endurance advantage in high temperatures, humans have a chance of running a more athletic prey to exhaustion.

Aircraft Propellers, an Outdated Innovation?

The race for speed ruled the early Jet Age on aviation. Aircraft manufacturers chased faster and faster planes in a fight for pride and capability. In the early 1970s, dreamed that the future would be supersonic, but fuel economy and not acceptable noise levels made that era never came. After the 1973 first oil crisis, the paradigm changed. The average cruise speed on newly developed aircraft started to decrease in exchange for improvements in many other performance parameters. At the same pace, the airliner’s powerplants are evolving to look more like a ducted turboprop, and less like a pure jet engine as the pursuit for the higher bypass ratios continues. However, since the birth of jet aircraft, the propeller-driven plane lost its dominant place in the market. Associated with the idea of going back to propeller-driven airplanes, and what it represented in terms of modernity and security, it started a propeller avoidance phenomenon on the travelers and thus on the airlines. Today, even with the modest research effort since the 1980s, the advanced propellers are getting closer efficiencies to the jet-powered engines at their contemporary typical cruise speeds. This paper gives a brief overview of the performance trends in aviation since the last century. Comparison examples between aircraft designed on different paradigms are presented. The use of propellers as a reborn propulsive device is discussed.&#x0D; Keywords: Propeller, Aircraft, Turboprop, Flight efficiency, Flight speed

Para-cycling race performance in different sport classes

Purpose The para-cycling classification system, consisting of five classes (C1–C5) for bicycling (C5 athletes having least impairments), is mostly based on expert-opinion rather than scientific evidence. The aim of this study was to determine the differences in race performance between para-cycling classes. Methods From official results of the men’s 1 km time trials for classes C1–C5 of seven Union Cycliste Internationale World Championships and Paralympics, median race speed of the five fastest athletes in each class was calculated (n = 175). Para-cycling results were expressed as a percentage of able-bodied performance using race results from the same years (n = 35). To assess differences between consecutive classes, Kruskal-Wallis tests with Mann-Whitney U post hoc tests were performed, correcting for multiple testing (p < 0.013). Results Para-cyclists in C1 reached 75% (median ± interquartile range = 44.8 ± 4.2 km/h) and in C5 90% (53.5 ± 2.9 km/h) of able-bodied race speed (59.4 ± 0.9 km/h). Median race speed between consecutive classes was significantly different (χ 2 = 142.6, p < 0.01), except for C4 (52.1 ± 2.8 km/h) and C5 (U = 447.0, p = 0.05). Conclusion Current para-cycling classification does not clearly differentiate between classes with least impairments. IMPLICATIONS FOR REHABILITATION The current classification system is not evidence-based and does not clearly differentiate between relevant groups of para-cyclists. An evidence-based para-cycling classification system is essential for a fair and equitable competition. Fair competition will make it more interesting and increase participation. Para-cycling can inspire everyone with and even those without disabilities to be physically active.

Race Analysis of the World's Best Female and Male Marathon Runners.

Background: Beyond the difference in marathon performance when comparing female and male runners, we tested the hypothesis that running strategy does not different according to sex. The goal of the present study is to compare the running strategy between the best female and male marathon performances achieved in the last two years. Methods: Two aspects of the races were analyzed: (i) average speed relative to runner critical speed (CS) with its coefficient of variation and (ii) asymmetry and global tendency of race speed (i.e., the race’s Kendall . Results: The females’ best marathons were run at 97.6% ± 3% of CS for the new record (Brigid Kosgei, 2019) and at 96.1% ± 4.4% for the previous record (Paula Radcliffe, 2003). The best male performances (Eliud Kipchoge, 2018 and 2019) were achieved at a lower fraction of CS (94.7% ± 1.7% and 94.1% ± 2.3% in 2018 and 2019, respectively). Eliud Kipchoge (EK) achieved a significant negative split race considering the positive Kendall’s of pacing (i.e., time over 1 km) ( = 0.30; p = 0.007). Furthermore, EK ran more of the average distance below average speed (54% and 55% in 2018 and 2019, respectively), while female runners ran only at 46% below their average speed. Conclusions: The best female and male marathon performances were run differently considering speed time course (i.e., tendency and asymmetry), and fractional use of CS. In addition, this study shows a robust running strategy (or signature) used by EK in two different marathons. Improvement in marathon performance might depend on negative split and asymmetry for female runners, and on higher fractional utilization of CS for male runners.

Do Fast Older Runners Pace Differently From Fast Younger Runners in the "New York City Marathon"?

Nikolaidis, PT and Knechtle, B. Do fast older runners pace differently from fast younger runners in the "New York City Marathon"? J Strength Cond Res 33(12): 3423-3430, 2019-Although pacing strategies in the marathon and generally in endurance running have been well studied with regard to the effects of age group and performance level, little is known for their interaction. Thus, the aim of this was to examine whether fast runners of different age differ for pacing. Finishers (women, n = 117,595; men, n = 180,487) in the "New York City" Marathon between 2006 and 2016 were analyzed in 5-year age groups. To examine the effect of performance, we created performance groups according to quartiles of average race speed (Q1-the fastest, Q2, Q3, and Q4-the slowest). A large main effect of split on race speed was observed in women and men with the fastest speed in the 5-10-km split and the slowest in the 35-40-km. Compared with the other performance groups, the slowest group had the largest percentage decrease in speed at 5, 10, 15, and 20 km but the largest percentage increase in speed at 35 and 40 km. The fastest group had the least decrease during the race and the least increase at 40 km. A trivial split × age group interaction on race speed was observed for all performance groups in both sexes. This interaction was more pronounced in Q4. Based on these findings, coaches should advise their slow master runners to adopt age-tailored pacing strategy, whereas their fast master runners should adopt similar pacing as the younger fast runners.

Muscle Strength and Flexibility in Male Marathon Runners: The Role of Age, Running Speed and Anthropometry.

Most studies on marathon runners have focused on physiological parameters determining performance, whereas neuromuscular aspects, such as muscle strength and flexibility, have received less attention. Thus, the aim of the present study was to examine the relationship of age, body composition, and running speed with muscle strength and flexibility of recreational marathon runners. Male marathon runners (n = 130, age 44.1 ± 8.6 years, height 176 ± 6 cm, body mass 77 ± 9 body mass index 24.7 ± 2.6 kg.m–2, and race speed 10.29 ± 1.87 km/h) were separated into eight age groups (<30, 30–35, 55–60, >60 years). Four weeks before competing in a marathon, participants performed the sit-and-reach test (SAR), squat jumps (SJ), and countermovement jumps (CMJ), and four isometric muscle strength tests (right and left handgrip, lifting with knees extended and flexed), providing an index of overall isometric muscle strength in absolute (kg) relative to body mass values (kg.kg–1 body mass). Afterward, participants competed and finished the Athens Classic Marathon (2017), and race speed was used as an index of running performance. As an average for the whole sample, SAR was 17.6 ± 8.5 cm, SJ was 24.3 ± 4.2 cm, CMJ was 25.8 ± 4.8 cm, overall isometric muscle strength was 386 ± 59 kg in absolute values and 5.06 ± 0.78 kg/kg of body mass in relative terms. The older age groups had the lowest scores in SJ (p < 0.001, ηp2 = 0.298) and CMJ (p < 0.001, ηp2 = 0.304), whereas no age-related difference in SAR (p = 0.908, ηp2 = 0.022), absolute (p = 0.622, ηp2 = 0.042) and relative isometric muscle strength (p = 0.435, ηp2 = 0.055) was shown. Race speed correlated moderately with relative isometric strength (r = 0.42, p < 0.001), but not with the other neuromuscular measures (r < 0.13,p > 0.130). In summary, age-related differences were shown in jumping ability, but not in flexibility and isometric muscle strength. Although these parameters - except relative strength - did not relate to running speed, they were components of health-related physical fitness. Consequently, coaches and runners should consider exercises that include stretching and strengthening in their weekly program to ensure adequate levels for all components of health-related physical fitness.

Bayesian approach to quantify morphological impact on performance in international elite freestyle swimming

ObjectivesThe purpose of this study was to quantify the impact of morphological characteristics on freestyle swimming performance by event and gender.DesignHeight, mass, body mass index (BMI) and speed data were...

Effects of using the Tempo Trainer tool on numerical level of 50 meters butterfly Swimming

That the main purpose of the training is to achieve the best numerical achievement for swimmer, and the 50 meters butterfly race considered one of important speed racing, which requires training for the development of both strokes length and stroke rate of arms, The arm rate is also an important indicator of both the tempo and timing of the butterfly swim. The very low stroke rate is a sign of slow movement of the arms and indicates that there is an instantaneous stopover during performance that effects on race time negatively Research aim. This research aims to improve the numerical level of 50 meters butterfly swim by using Tempo Trainer tool. Research hypotheses: 1- There are statistically significant differences between the pre and post measurements in the numerical level of 50 m butterfly swim for the benefit of post measurements.

The relationship between microstructure, stiffness and compressive fatigue life of equine subchondral bone

Subchondral bone injuries often precede articular cartilage damage in osteoarthritis and are common in thoroughbred racehorses due to the accumulation of fatigue damage from high speed racing and training. Thus, racehorses provide a model to investigate the role of subchondral bone in joint disease. We assessed the association of horse and racing related factors and micro-CT based micromorphology of three separate subchondral bone layers with the initial stiffness and compressive fatigue life of bone plugs. Furthermore, we investigated three different definitions of fatigue failure of subchondral bone during compressive fatigue testing. Initial stiffness was 2,362 ± 443 MPa (mean ± standard deviation). Median compressive fatigue life during cyclic loading to -78 MPa was 16,879 (range 210 to 57,064). Subchondral bone stiffness increased over a median of 24% (range 3%–42%) of fatigue life to a maximum of 3,614 ± 635 MPa. Compressive fatigue life was positively associated with bone volume fraction in the deeper layers of subchondral bone, maximal stiffness, and the number of cycles to maximal stiffness. Initial stiffness was positively associated with tissue mineral density in the deeper layers and bone volume fraction in the superficial layer. Most specimens with a fatigue life of less than 5,500 cycles fractured grossly before reaching 30% reduction of maximal stiffness. Cycles to 10% reduction of maximal stiffness correlated strongly with cycles to lowest recorded stiffness at gross fracture and thus is a valid alternative failure definition for compressive fatigue testing of subchondral bone. Our results show that subchondral bone sclerosis as a result of high speed exercise and measured as bone volume fraction is positively associated with compressive fatigue life and thus has a protective effect on subchondral bone. Further research is required to reconcile this finding with the common collocation of fatigue damage in sclerotic subchondral bone of racehorses.