Professional Road Research Articles

Uncertainty of Outcome and Radio Policy in Professional Road Cycling

The world governing body for cycling proscribed the use of two-way radio communication in road cycling races, with the ban set to become fully effective in 2012. The ban was instituted because radio use was perceived to have altered the cycling competitions by making outcomes more predictable and of less interest to sport’s consumers. This empirical analysis of the policy rationale considers the uncertainty of outcome hypothesis (UOH) as it applies to professional cycling races and creates a novel measure, the likelihood of breakaway success (LBS). TheLBSis analyzed in 1436 bicycle races between 1985–2010 to examine potential changes in outcomes associated with the use of two-way radio technology by competitors and team directors. The data suggests that radio technology has had a significant association with event outcome types. The relevance of the findings to intraorganizational communication, management, and hierarchies of sports teams are also discussed.

Differences in the Contractile Properties of the Knee Extensor and Flexor Muscles in Professional Road Cyclists During the Season

The purpose of this study was to establish reference values of tensiomyography (TMG) in professional road cyclists and to examine how the planned periods of the Season produce differences in the muscles: vastus medialis (VM), vastus lateralis (VL), rectus femoris (RF), and biceps femoris (BF), and to determine how these differences may depend on each cyclist, the assessed muscle, and the side of the body. Ten professional road cyclists (27.5 ± 5.5 years; 178.2 ± 7.8 cm; 65.6 ± 5.46 kg; 72.1 ± 3.7 ml·kg·min V[Combining Dot Above]O2; 6 ± 0.4 W·kg) were assessed by TMG, in microcycle recovery, at 2 moments of periods during the season: preparation period (PP) and competition period (CP). Student's t contrast for paired groups, Cohen's d effect sizes, and a repeated measures analysis of variance (ANOVA) was applied. We did not find significant differences (p < 0.01) between the lower limbs. The results showed a significantly large increment between the time contraction (TC) values of the PP and CP in the muscles VM (28.7 ± 5.5 vs. 40.6 ± 14.4 milliseconds; 41.4%, p < 0.05, d = 1.1), VL (28.3 ± 4.9 vs. 40.6 ± 10.2 milliseconds; 43.4%, p < 0.05, d = 1.53), and RF (35.9 ± 6.9 vs. 45.9 ± 16.2 milliseconds; 27.8%, p < 0.05, d = 0.8). Nevertheless, TC of the BF presents a significantly large decrease in the CP (35.9 ± 9.9 vs. 28.2 ± 5.2 milliseconds; -21.4%, p < 0.05, d = 0.97). Radial muscle displacement (DM) values are slightly lower during the CP, but the difference is not significant. ANOVA confirmed that these differences depend on the evaluated muscles (TC p = 0.02; DM p = 0.001) and on the cyclists (TC p = 0.001; DM p = 0.001) and does not depend on the side of the body. In conclusion, the TC values during the Season show marked differences between the knee extensors (large increased) and the knee flexor (large decreased). The DM has not changed significantly, keeping the muscular and tendon stiffness.

Geometric-based approach for integrating VGI POIs and road networks

Integrating heterogeneous spatial data is a crucial problem for geographical information systems (GIS) applications. Previous studies mainly focus on the matching of heterogeneous road networks or heterogeneous polygonal data sets. Few literatures attempt to approach the problem of integrating the point of interest (POI) from volunteered geographic information (VGI) and professional road networks from official mapping agencies. Hence, the article proposes an approach for integrating VGI POIs and professional road networks. The proposed method first generates a POI connectivity graph by mining the linear cluster patterns from POIs. Secondly, the matching nodes between the POI connectivity graph and the associated road network are fulfilled by probabilistic relaxation and refined by a vector median filtering (VMF). Finally, POIs are aligned to the road network by an affine transformation according to the matching nodes. Experiments demonstrate that the proposed method integrates both the POIs from VGI and the POIs from official mapping agencies with the associated road networks effectively and validly, providing a promising solution for enriching professional road networks by integrating VGI POIs.

SportsTech: Cycling

At its heart a bike is a fairly simple engineering enterprise; a frame for support, two wheels for traction, direct drive gears and chain for power, and handlebars to steer. But when it comes to professional road racing, the complexity multiplies. Although injury has prevented Sir Bradley Wiggins defending his 2012 Tour de France crown when the race begins on 29 June, Team Sky will still field a strong squad including Chris Froome. The Kenyan-born cyclist, who rides for Great Britain, claimed a bronze in the individual time trial at the London Olympics last year. The highly engineered machines that Froome and his team mates will race over the 23 days, 3360 Km and 21 stages of Le Tour, are as far away from the road bikes that cycle the roads of the UK as a Formula One car is from a Ford Focus. Much like a Formula One car, a professional bike is the sum of all its parts; chassis, wheels, tyres and gears. The frames raced by Team Sky come from Italian manufacturer Pinarello; the Dodma 2 chassis for road racing and the Bolide for time trials.

Biomechanical assessment of a professional road cyclist following recovery from severe injury: A case report

The incidence of injury in top level road cyclists is relatively high. In a recent longitudinal study over four years using a cohort of elite road cyclists it was documented that only 15.6 % remained injury free. Acute fracture injuries accounted for 48.5 % of the total number of injuries with 26.5 % of these acute injuries being sustained in the lower extremities. This case report refers to an elite level, professional, road cyclist who returned to competition following severe fractures to the left femur and right ankle, sustained during a serious road traffic accident. The athlete reported power imbalances and feeling of dysfunction upon their return to competition. Bilateral 3-D kinematics and EMG analyses of the lower extremities were obtained. Clear asymmetries were observed in a number of 3-D kinematic parameters. These suggest an overreliance on coronal and transverse plane motions to compensate for reductions in sagittal plane movement as a result of the injury. Such outcomes have both clinical and performance implications which are discussed fully. This innovative use of advanced 3-D kinematic analysis in conjunction with isokinetic and electromyographic techniques shows the value of sports science support in improving long term performance outcomes, following a significant period of rehabilitation.

A probabilistic relaxation approach for matching road networks

Geospatial data matching is an important prerequisite for data integration, change detection and data updating. At present, crowdsourcing geospatial data are attracting considerable attention with its significant potential for timely and cost-effective updating of geospatial data and Geographical Information Science (GIS) applications. To integrate the available and up-to-date information of multi-source geospatial data, this article proposes a heuristic probabilistic relaxation road network matching method. The proposed method starts with an initial probabilistic matrix according to the dissimilarities in the shapes and then integrates the relative compatibility coefficient of neighbouring candidate pairs to iteratively update the initial probabilistic matrix until the probabilistic matrix is globally consistent. Finally, the initial 1:1 matching pairs are selected on the basis of probabilities that are calculated and refined on the basis of the structural similarity of the selected matching pairs. A process of matching is then implemented to find M:N matching pairs. Matching between OpenStreetMap network data and professional road network data shows that our method is independent of matching direction, successfully matches 1:0 (Null), 1:1 and M:N pairs, and achieves a robust matching precision of above 95%.

Lance Armstrong’s Era of Performance – Part III: Demonstrating the Post Hoc Fallacy

In consequence of USADA’s charges, Lance Armstrong conceded he doped during his cycling career. The logic proposed in the post hoc fallacy entails that Armstrong’s sportive feats are therefore ‘caused’ by his doping use. This fallacy generalizes to the belief put forward in the doping debate that the progress in speed over time in professional cycling is determined by riders’ use of progressively potent doping agents. To examine this fallacy, the current study compared Armstrong’s mountain time trial wins, realized in the Tour de France (2001, 2004), to victories demonstrated by riders in similar races uphill in the French race (1958–1996, N = 17). The fallacy expects that riders will race faster over time and that Armstrong’s achievements will be far superior to other riders. However, if these expectations are disconfirmed the fallacy will be refuted. We developed a climbing index to evaluate riders’ km/h performances: ClI = (Corrected altitude climb / Distance trial) ● 100. Higher values indicate more demanding races. Mediation regression analyses showed that, over time, the trials became less demanding, b = -.0076 (∆R2 = .201, p ≤ .05), and that riders raced b = 0.201 km/h faster per year (∆R2 = .234, p ≤ .05). The index had a robust influence on riders’ speed (r = -.97) and they raced b = -2.302 km/h slower per unit of the index (∆R2 = .932, p ≤ .0001). The significant mediating influence of the index, b = 0.175 km/h (p ≤ .05), subsequently reduced riders’ progress in speed to a nonsignificant b = 0.026 km/h per year (p = .38, ∆R2 = .003). Furthermore, Armstrong’s performances did not prove to be outliers. Findings invalidate the reasoning employed in the post hoc fallacy, since the CLI and not the year in which riders competed constitutes the main determinant of riders’ performances. They also entail that Armstrong’s modern doping agents may not have given him the proposed advantage over his forerunners who won trials before the 1990s, i.e., the years in which these potent aids were not yet rampant in professional road racing.

Performance Analysis of a World-Class Sprinter During Cycling Grand Tours

This investigation describes the sprint performances of the highest internationally ranked professional male road sprint cyclist during the 2008-2011 Grand Tours. Sprint stages were classified as won, lost, or dropped from the front bunch before the sprint. Thirty-one stages were video-analyzed for average speed of the last km, sprint duration, position in the bunch, and number of teammates at 60, 30, and 15 s remaining. Race distance, total elevation gain (TEG), and average speed of 45 stages were determined. Head-to-head performances against the 2nd-5th most successful professional sprint cyclists were also reviewed. In the 52 Grand Tour sprint stages the subject started, he won 30 (58%), lost 15 (29%), was dropped in 6 (12%), and had 1 crash. Position in the bunch was closer to the front and the number of team members was significantly higher in won than in lost at 60, 30, and 15 s remaining (P < .05). The sprint duration was not different between won and lost (11.3 ± 1.7 and 10.4 ± 3.2 s). TEG was significantly higher in dropped (1089 ± 465 m) than in won and lost (574 ± 394 and 601 ± 423 m, P < .05). The ability to finish the race with the front bunch was lower (77%) than that of other successful sprinters (89%). However, the subject was highly successful, winning over 60% of contested stages, while his competitors won less than 15%. This investigation explores methodology that can be used to describe important aspects of road sprint cycling and supports the concept that tactical aspects of sprinting can relate to performance outcomes.

Does limited gear ratio driven higher training cadence in junior cycling reflect in maximum effort sprint?

Rannama I, Port K, Bazanov B. Does limited gear ratio driven higher training cadence in junior cycling reflect in maximum effort sprint?. J. Hum. Sport Exerc. Vol. 7, No. Proc1, pp. S85-S90, 2012. Maximum gears for youth category riders are limited. As a result, youth category riders are regularly compelled to ride in a high cadence regime. The aim of this study was to investigate if regular work at high cadence regime due to limited transmission in youth category riders reflects in effectual cadence at the point of maximal power generation during the 10 second sprint effort. 24 junior and youth national team cyclist’s average maximal peak power at various cadence regimes was registered on Cyclus-2 ergometer using cyclists own bikes. Effectual cadence at the point of maximal power generation (group average 113.9±10.6 rpm) is similar to the values of professional road cyclist during the last 200m sprinting to finish where 10 second average cadence is 109.9±5.3 rpm and highest average cadence is 117.6±6.1 rpm. The premise that regular work at high cadence regime due to limited transmission in youth category riders reflects in effectual cadence at the point of maximal power generation during the 10 second sprint effort was not corroborated. Key words: CYCLUS-2 ERGOMETER, MAXIMAL POWER, ISOKINETIC, YOUTH CATEGORY.

Are mitochondrial haplogroups associated with elite athletic status? A study on a Spanish cohort

There is increasing evidence regarding the association between mitochondrial DNA (mtDNA) and aerobic capacity; however, whether mtDNA haplogroups are associated with the status of being an elite endurance athlete is more controversial. We compared the frequency distribution of mtDNA haplogroups among the following groups of Spanish (Caucasian) men: 102 elite endurance athletes (professional road cyclists, endurance runners), 51 elite power athletes (jumpers, throwers and sprinters), and 478 non-athletic controls. We observed a significant difference between endurance athletes and controls (Fisher exact test=17.89, P=0.015; Bonferroni's significant threshold=0.017), yet not between power athletes and controls (Fisher exact test=47.99, P=0.381) or between endurance and power athletes (Fisher exact test=5.53, P=0.597). We observed that the V haplogroup was overrepresented in endurance athletes (15.7%) compared with controls (7.5%) (odds ratio: 2.284; 95% confidence interval: 1.237, 4.322). In conclusion, our findings overall support the idea that mtDNA variations could be among the numerous contributors to the status of being an elite endurance athlete, whereas no association was found with elite power athletic status.

Are ‘Endurance’ Alleles ‘Survival’ Alleles? Insights from the ACTN3 R577X Polymorphism

Exercise phenotypes have played a key role for ensuring survival over human evolution. We speculated that some genetic variants that influence exercise phenotypes could be associated with exceptional survival (i.e. reaching ≥100years of age). Owing to its effects on muscle structure/function, a potential candidate is the Arg(R)577Ter(X) polymorphism (rs1815739) in ACTN3, the structural gene encoding the skeletal muscle protein α-actinin-3. We compared the ACTN3 R577X genotype/allele frequencies between the following groups of ethnically-matched (Spanish) individuals: centenarians (cases, n = 64; 57 female; age range: 100–108 years), young healthy controls (n = 283, 67 females, 216 males; 21±2 years), and humans who are at the two end-points of exercise capacity phenotypes, i.e. muscle endurance (50 male professional road cyclists) and muscle power (63 male jumpers/sprinters). Although there were no differences in genotype/allele frequencies between centenarians (RR:28.8%; RX:47.5%; XX:23.7%), and controls (RR:31.8%; RX:49.8%; XX:18.4%) or endurance athletes (RR:28.0%; RX:46%; XX:26.0%), we observed a significantly higher frequency of the X allele (P = 0.019) and XX genotype (P = 0.011) in centenarians compared with power athletes (RR:47.6%; RX:36.5%;XX:15.9%). Notably, the frequency of the null XX (α-actinin-3 deficient) genotype in centenarians was the highest ever reported in non-athletic Caucasian populations. In conclusion, despite there were no significant differences with the younger, control population, overall the ACTN3 genotype of centenarians resembles that of world-class elite endurance athletes and differs from that of elite power athletes. Our preliminary data would suggest a certain ‘survival’ advantage brought about by α-actinin-3 deficiency and the ‘endurance’/oxidative muscle phenotype that is commonly associated with this condition.

Overuse Injuries in Professional Road Cyclists

Background Little epidemiological information exists on overuse injuries in elite road cyclists. Anecdotal reports indicate anterior knee pain and lower back pain may be common problems. Purpose This study was conducted to register overuse injuries among professional road cyclists with special focus on anterior knee and lower back pain. Study Design Descriptive epidemiology study. Methods We attended training camps of 7 professional teams and interviewed 109 of 116 cyclists (94%) on overuse injuries they had experienced in the previous 12 months. Injuries that required attention from medical personnel or involved time loss from cycling were registered. Additional information on anterior knee pain and lower back pain was collected using specific questionnaires. Results A total of 94 injuries were registered; 45% were in the lower back and 23% in the knee. Twenty-three time-loss injuries were registered—57% in the knee, 22% in the lower back, and 13% in the lower leg. Fifty-eight percent of all cyclists had experienced lower back pain in the previous 12 months, and 41% of all cyclists had sought medical attention for it. Thirty-six percent had experienced anterior knee pain and 19% had sought medical attention for it. Few cyclists had missed competitions because of pain in the lower back (6%) or anterior knee (9%). Conclusion Lower back pain and anterior knee pain were the most prevalent overuse injuries, with knee injuries most likely to cause time loss and lower back pain causing the highest rates of functional impairment and medical attention. Clinical Relevance Future efforts to prevent overuse injuries in competitive cyclists should focus on lower back pain and anterior knee pain.

Competition among contests

When several contests compete for the participation of a common set of players, a contest's allocation of prizes not only induces incentive effects but also participation effects. Our model predicts that an increase in the sensitivity with which contest outcomes depend on players' efforts makes flatter prize structures more attractive to participants. In equilibrium, contests that aim to maximize the number of participants will award multiple prizes if and only if this sensitivity is sufficiently high. Moreover, the prize awarded to the winner is decreasing in the contests' sensitivity. We provide empirical evidence from professional road running using race–distance as a measure of sensitivity. We show that steeper prize structures are more attractive to top‐ranked runners in longer, that is, less sensitive, races. In line with our theory, longer races do in fact offer steeper prize structures.

Submaximal Relative Mechanical Power Output Is A Requirement To Be A Professional Road Cyclist

Numerous studies in the scientific literature show the determinant performance factors in professional road cyclists. Nevertheless, there are some submaximal variables, probably related to endurance cycling performance, that remain to be studied. PURPOSE: To assess new physiological and mechanical factors that could be considered a requirement to become a professional cyclist. METHODS: 161 cyclists of different levels of performance (13 professional and 148 amateurs, age 20.9 ± 3.9 yr) performed a laboratory test on a cyclergometer. Warm-up: 100W·10 min-1, initial workload: 200 W followed by 30 W increments every 4 min until exhaustion. All the tests were performed throughout a 10 year-period during the competitive phase of a cycling season (February to May). Dietary intake and resting period were controlled two days before the tests in order to maximize the test results. Subsequently, relative (W·kg-1) and absolute (W) mechanical power output at different fixed blood lactate concentrations (2, 3, 4, and 5 mmol·l-1), maximal absolute and relative mechanical power output (Wmax·kg-1, Wmax), and VO2max, expressed as L·min-1, mL·kg-1·min-1, and mL·kg-3/4·min-1, were measured and further analyzed using a backward stepwise multivariate logistic regression analysis to evaluate the aforementioned physiological parameters as potential predictors to be a professional cyclist. The level of significance was set at P < 0.05. RESULTS: The logistic regression analysis showed that VO2max expressed as mL·kg-1·min-1 and L·min-1 as well as mechanical power output expressed in absolute or relative terms were not good predictors to become a professional cyclist. Nevertheless, VO2max expressed as mL·kg-3/4·min-1 (P<0,01), W·kg-1(3mM) (P<0,01), W·kg-1(4mM) (P<0,01), and W·kg-1(5mM) (P<0,05) were significant predictors for becoming a professional road cyclist. CONCLUSION: To become a professional cyclist it is important to have a high relative VO2max (mL·kg-3/4·min-1), W·kg-1(2mM), W·kg-1(4mM), W·kg-1(5mM). It is important to emphasize that W·kg-1 at different submaximal intensities is also an important requirement to become a professional road cyclist, although these variables have not been well studied in the past. This study opens a new perspective to evaluate the performance of professional road cyclists.

Muscle Efficiency Improves over Time in World-Class Cyclists

To determine the change in muscular efficiency in world-class professional cyclists during years of training/competition. Twelve male world-class professional road cyclists (mean +/- SD: age = 22.6 +/- 3.8 yr and VO(2max) = 75.5 +/- 3.3 mL x kg(-1) x min(-1)) performed an incremental test (starting at 100 W with workload increases of 50 W every 4-min interval until volitional exhaustion) before and after a five-season period. Delta efficiency (DE) was calculated from 100 W to that power output (PO) in which the RER was 1. DE increased (P < 0.01) from 23.61 +/- 2.78% to 26.97 +/- 3.7% from the first to the fifth year, whereas VO(2max) showed no significant increase. A significant inverse correlation (r = -0.620; P = 0.032) between DE and VO(2max) (mL x kg(-1) x min(-1)) was found in the fifth year, whereas no significant correlation between these variables was found in the first year. A significant inverse correlation (r = -0.63; P = 0.029) was found between the increase percentage in DE (DeltaDE) and VO(2max) (mL x kg(-1) x min(-1)) in the fifth year, whereas no significant correlation was found between these variables in the first year. The results show an increase in DE in world-class professional cyclists during a five-season training/competition period, without significant variations in VO(2max). The results also suggest that the increase in DE could be a possible way for performance compensation, especially in those subjects with lower VO(2max).

Understanding Change in Professional Road Cycling

The decision in 2005 of the world governing body of cycling, the Union Cycliste Internationale (UCI), to introduce a new competition, the UCI Pro Tour, was a highly significant development in professional road cycling. Using this development as the case study setting, this paper draws on stakeholder theory and network theory to examine this changing environment. Drawing on a series of semi-structured interviews with key stakeholders, complemented by analysis of publicly available information, this study explores how this process of change has affected the professional road cycling network, the interaction between its stakeholders and the balance of power among those stakeholders. While commercialism has a long history in professional road cycling, the paper concludes that the change process has been driven by a wish for commercial deepening within the network and by a desire to challenge some of the well-established relationships and dependencies that have existed therein.

Competition Amongst Contests

This article analyses the allocation of prizes in contests. While existing models consider a single contest with an exogenously given set of players, in our model several contests compete for participants. As a consequence, prizes not only induce incentive effects but also participation effects. We show that contests that aim to maximize players’ aggregate effort will award their entire prize budget to the winner. In contrast, multiple prizes will be awarded in contests that aim to maximize participation and the share of the prize budget awarded to the winner increases in the contests’ randomness. We also provide empirical evidence for this relationship using data from professional road running. In addition, we show that prize structures might be used to screen between players of differing ability.

Glycaemic Control in Athletes

Physical activity is essential for weight control, for limiting onset and complications of chronic disorders and for preventing impaired insulin sensitivity. Little is known about the glycaemic adaptations of physically active subjects, especially elite and professional athletes. Thus, we evaluated the glycaemic control in elite and professional cyclists by assessing fasting plasma glucose (FPG) and glycated haemoglobin (HbA1c). The study population consisted of 47 male professional road cyclists, 72 male elite road cyclists and 58 male sedentary blood donors. A significant difference was observed for FPG between sedentary controls (96 +/- 8 mg/dL) and either elite (91 +/- 8 mg/dL; p < 0.001) or professional cyclists (89 +/- 8 mg/dl; p < 0.001). Athletes showed a consistent trend towards higher HbA1c values, reaching statistical significance between sedentary individuals and professional cyclists (5.2 +/- 0.3% versus 5.4 +/- 0.2%; p = 0.017). In multiple linear regression analysis, the intensity of physical exercise is inversely correlated with FPG (r = - 0.320; p < 0.001) and directly correlated with HbA1c (r = 0.190; p = 0.006). These results demonstrate a significant association between intensity of the training regimen and both FPG and HbA1c, highlighting the need for establishing the appropriate critical difference for the measurement of FPG and HbA1c according to the training and exercise workload.

Heart Rate Response to Professional Road Cycling: The Tour de France

The aim of the present investigation was to evaluate the heart rate response of 8 professional cyclists (2:6±3 yr; 68.9±5.2 kg; VO2max: 74.0±5.8 ml·kg-1 min-1) during the 3-week Tour de France as an indicator of exercise intensity. Subjects wore a heart rate telemeter during 22 competition stages and recorded data were analysed using computer software. Two reference heart rates (corresponding to the first and second ventilatory thresholds or VT1 and VT2) were used to establish three levels of exercise intensity defined as phases I (<VT1), II (VT1 -VT2) and III (<VT2). The average total time spent by each subject in each of the 3 phases respectively was approximately 71, 23 and 8 h. The relative contributions of each phase were 70, 23 and 7 %. The percentage relative contribution of each phase was significantly different (p<0.01) in each of the competition stages (time trials, flat stages, „high-mountain” stages and „medium-mountain” stages). Exercise intensity was particularly high during the time trials and high mountain stages. It may be concluded that during an endurance event such as the Tour de France, although the overall contribution of moderate (VT1 to VT2) or high intensity exercise (> VT2) is substantially lower than that of light, aerobic exercise (< VT1), a clear distinction must be made between the different type of stages (i.e. easy, flat parcours vs mountain stages or time trials) and the role of each cyclist in the team must be also considered.

Chronic influence of demanding physical exercise on venous blood-gas status

Although there is comprehensive information on several parameters related to acute changes of the oxygen transport system in athletes, little information is available on chronic adaptations of the respiratory system at rest, as reflected by the out-of-competition venous blood-gas status. Such changes may represent markers of a more efficient oxygen metabolism at rest, associated with a superior physical recovery. Venous blood-gas status was investigated in two subpopulations of competitive athletes (47 male professional road cyclists, 72 male elite road cyclists) who had observed an 18-24-h resting period from the last training session, and 58 male sedentary blood donors. Significant differences were observed for the p50 values (the oxygen tension at which the haemoglobin is 50% saturated) between sedentary controls (25+/-1 mmHg) and either elite (26+/-1 mmHg; p<0.01) or professional athletes (27+/-0.8; p<0.01), whereas other conventional parameters of the venous blood-gas status (pH, P(O2), P(CO2) and saturation) did not differ significantly between the three study populations. Results of the present investigation suggest that intensive training may be associated with a right-shift of the standard oxygen dissociation curve, as attested by the increased p50. This rightward shift is usually considered a helpful adaptation, enabling a relatively more efficiently mechanism of oxygen delivery to the peripheral tissues, enabling physiological advantages during exercise and improved recovery.