Biomechanical factors associated with running economy and performance of elite Kenyan distance runners: A systematic review

The biomechanics of running and running styles: a synthesis

Running movements are parametrised using a wide variety of devices. Misleading interpretations can be avoided if the interdependencies and redundancies between biomechanical parameters are taken into account. In this synthetic review, commonly measured running parameters are discussed in relation to each other, culminating in a concise, yet comprehensive description of the full spectrum of running styles. Since the goal of running movements is to transport the body centre of mass (BCoM), and the BCoM trajectory can be derived from spatiotemporal parameters, we anticipate that different running styles are reflected in those spatiotemporal parameters. To this end, this review focuses on spatiotemporal parameters and their relationships with speed, ground reaction force and whole-body kinematics. Based on this evaluation, we submit that the full spectrum of running styles can be described by only two parameters, namely the step frequency and the duty factor (the ratio of stance time and stride time) as assessed at a given speed. These key parameters led to the conceptualisation of a so-called Dual-axis framework. This framework allows categorisation of distinctive running styles (coined 'Stick', 'Bounce', 'Push', 'Hop', and 'Sit') and provides a practical overview to guide future measurement and interpretation of running biomechanics.

Variability in Running Economy of Kenyan World-Class and European Amateur Male Runners with Advanced Footwear Running Technology: Experimental and Meta-analysis Results

BACKGROUND

Advanced footwear technology improves average running economy compared with racing flats in sub-elite athletes. However, not all athletes benefit as performance changes vary from a 10% drawback to a 14% improvement. The main beneficiaries from such technologies, world-class athletes, have only been analyzed using race times.

OBJECTIVE

The aim of this study was to measure running economy on a laboratory treadmill in advanced footwear technology compared to a traditional racing flat in world-class Kenyan (mean half-marathon time: 59:30 min:s) versus European amateur runners.

METHODS

Seven world-class Kenyan and seven amateur European male runners completed a maximal oxygen uptake assessment and submaximal steady-state running economy trials in three different models of advanced footwear technology and a racing flat. To confirm our results and better understand the overall effect of new technology in running shoes, we conducted a systematic search and meta-analysis.

RESULTS

Laboratory results revealed large variability in both world-class Kenyan road runners, which ranged from a 11.3% drawback to a 11.4% benefit, and amateur Europeans, which ranged from a 9.7% benefit to a 1.1% drawback in running economy of advanced footwear technology compared to a flat. The post-hoc meta-analysis revealed an overall significant medium benefit of advanced footwear technology on running economy compared with traditional flats.

CONCLUSIONS

Variability of advanced footwear technology performance appears in both world-class and amateur runners, suggesting further testing should examine such variability to ensure validity of results and explain the cause as a more personalized approach to shoe selection might be necessary for optimal benefit.

Sources of information used by elite distance running coaches for selection decisions

Talent identification and selection are critical components of competitive sport success. Despite the time, effort, and resources invested, the accuracy of selection decisions remains generally poor. While much of the scholarship in this area has focused on the factors discriminating skilled and less-skilled individuals, limited research exists on what information is used in the decision-making process for athlete selection. The current study seeks to gain a better understanding of the information used by elite distance running coaches when forming judgements for athlete selection. Ten semi-structured interviews with elite distance running coaches from across Canada were transcribed and analyzed using inductive thematic analysis. It was interpreted that coaches mainly gather information using their coach’s eye to determine an athlete’s ‘fit’ to the team. Coaches also use more objective information such as race times and movement analyses to assess performance and judge future ‘potential’. As well, the decisions were believed to be influenced by situational considerations at the time of the selection procedure. Specifically, these considerations affecting a coach’s selection included length of time to make a decision, personal limitations in decision-making abilities, and team circumstances. Interestingly, coaches recognized limitations in their selection practices and procedures and discussed some of their personal and system-level biases, highlighting their awareness of potential selection inefficiencies/inaccuracies. Overall, distance running coaches used a variety of techniques to gather information before a selection was made, relying on both subjective and objective information for crafting judgments. Findings are discussed in relation to implications for coaches, sport organizations, and talent identification and selection programs.

Are Individual and Environmental Characteristics Associated With Running Performance in Female Runners of Different Age Categories?

The purpose of this study was to identify the individual and environmental predictors associated with performance in female runners of different ages. The sample comprised 440 female Brazilian runners, who answered an online questionnaire, that provided information regarding height, weight, age (categories: “young adult”, “adult”, “early middle-age”, and “older adults”), socioeconomic status, and training characteristics (frequency and volume per week, running pace, race event, and running club participation). Information about environmental variables was obtained from the official institutes and comprised the human development index (HDI), athletics events, athletic tracks, and female homicide. A linear regression model, clustered by state and performed by age groups, was computed. The sample presented a mean running pace of 5:57min/km, and a mean BMI of 23.51kg/m⁻². An increase in running pace and volume/week was observed with increasing age. In “young adults”, any of the variables were significantly associated with the performance. In “adult” group, only individual characteristics were statistically significantly related with the performance. In “early middle-age”, besides BMI (β=5.72; 95%CI=3.65–7.79) and training volume (β=−0.67; 95%CI=−1.07 − −0.27), the HDI was associated with the performance (β=−23.30; 95%CI=−44.11 − −2.49). In older adults, it was found an association between socioeconomic status (β=−19.47; 95%CI=−32.29 − −6.65), practice time (β=142.92; 95%CI=89.34–196.50), running event participation (β=−80.12; 95%CI=−114.35− −45.88), athletic events (β=33.44; 95%CI=15.16–51.72), and female homicide (β=−0.11; 95%CI=−0.17 − −0.05) with the performance, highlighting the influence of both individual and environmental characteristics. Information about the role of these constraints, and their relationships, in female runners’ performance, can be used to guide the development of projects/strategies aiming to increase their involvement in physical activities and sports practice, through the promotion of a more “friendly environment” to women, and providing support for decision-makers when suggesting/implementing public policies.

Factors correlated with running economy among elite middle- and long-distance runners

Running economy (RE) at a given submaximal running velocity is defined as oxygen consumption per minute per kg body mass. We investigated RE in a group of 12 male elite runners of national class. In addition to RE at 14 and 18 km h-1 we measured the maximal oxygen consumption (VO2max ) and anthropometric measures including the moment arm of the Achilles tendon (LAch ), shank and foot volumes, and muscular fascicle lengths. A 3-D biomechanical movement analysis of treadmill running was also conducted. RE was on average 47.8 and 62.3 ml O2  min-1  kg-1 at 14 and 18 km h-1 . Maximal difference between the individual athletes was 21% at 18 km h-1 . Mechanical work rate was significantly correlated with VO2 measured in L min-1 at both running velocities. However, RE and relative work rate were not significantly correlated. LAch was significantly correlated with RE at 18 km h-1 implying that a short moment arm is advantageous regarding RE. Neither foot volume nor shank volume were significantly correlated to RE. Relative muscle fascicle length of m. soleus was significantly correlated with RE at 18 km h-1 . Whole body stiffness and leg stiffness were significantly correlated with LAch indicating that a short moment arm coincided with high stiffness. It is concluded that a short LAch is correlated with RE. Probably, a short LAch allows for storage of a larger amount of elastic energy in the tendon and influences the force-velocity relation toward a lower contraction velocity.

No Trends in the Age of Peak Performance among the Best Half-Marathoners and Marathoners in the World between 1997-2020

Background and Objectives: We examined the possible trend in the age of peak performance in elite endurance athletes according to sex, continent of athletes’ national citizenship, and ranking position. Since performance is a multifactorial trait, this information can be used to guide the long-term training and to plan the strategies related to the selection process of athletes. Materials and methods: Information of 1852 professional athletes, classified as top 20 performance of each year in marathon and half-marathon events between 1997 and 2020 were considered. Analysis of variance was computed to test differences in age between sex, continent, and rank position. Results: A significant difference between groups in the mean age of peak performance was observed (F (3, 1884) = 42,31; p < 0.001). For both sexes, half-marathoners were younger than marathoners (male, 25.6 ± 3.6 years vs. 28.0 ± 3.9 years; female, 27.5 ± 4.4 years vs. 28.4 ± 4.1). Female half-marathoners in 2004 presented the highest mean age (31.1 ± 4.8 years) compared to their peers in the years 1997, 2001, 2018 and 2019; among male half-marathoners, those in 1999 presented the highest mean age when compared to 2011, 2018, and 2019. Differences between the continents of athletes’ national citizenship were observed (F (4, 1884) = 62,85,601; p < 0,001). Asian runners presented the lowest mean age (26.5 ± 3.7 years), while their European peers presented the highest (31.1 ± 3.9 years). No significant interaction between sex and ranking position was verified. Differences were observed between sexes for categories “4th–10th positions” and “11th–20th” (F (1, 1879) = 23,114; p < 0.001). Conclusions: Over the last two decades, no clear trend was observed in the changes in the age of peak performance among endurance athletes of both sexes, but, in general, female half-marathoners tended to be significantly older than their male peers.

Effect of Achilles Tendon Mechanics on the Running Economy of Elite Endurance Athletes

The Achilles tendon stores and releases strain energy, influencing running economy. The present study aims to verify the influence of the Achilles tendon tangent modulus, as a material property, on running economy by comparing two groups of elite endurance-performance athletes undergoing different running training volumes. Twelve athletes, six long-distance runners and six pentathletes, were studied. Long-distance runners had a higher weekly running training volume (116.7±13.7 vs. 58.3±20.4 km, p<0.05) and a better running economy (204.3±12.0 vs. 222.0±8.7 O₂ mL ∙ kg^-1 ∙ km^-1, p<0.05) evaluated in a treadmill at 16 km·h^-1, 1% inclination. Both groups presented similar VO_2max (68.5±3.8 vs. 65.7±5.0 mL ∙ min^-1 ∙ kg^-1, p>0.05). Achilles tendon tangent modulus was estimated from ultrasound-measured deformations, with the ankle passively mobilized by a dynamometer. True stress was calculated from the measured torque. The long-distance runners had a higher maximum tangent modulus (380.6±92.2 vs. 236.2±82.6 MPa, p<0.05) and maximum true stress than pentathletes (24.2±5.1 vs. 16.0±3.5 MPa, p<0.05). The correlation coefficient between tangent modulus at larger deformations was R=-0.7447 (p<0.05). Quantifying tendon tissue adaptations associated with different running training volumes will support subject and modality-specific workouts prescription of elite endurance athletes.