scholarly journals Bouncing behavior of sub-four minute milers

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Geoffrey T. Burns ◽  
Richard Gonzalez ◽  
Jessica M. Zendler ◽  
Ronald F. Zernicke
Keyword(s):  
Distance Runners ◽  
Mass Model ◽  
Vertical Stiffness ◽  
Leg Stiffness ◽  
Elite Level ◽  
Spatiotemporal Behavior ◽  
Lower Variability ◽  
Temporal Measures ◽  
Impact Angles ◽  
Elite Runners

AbstractElite middle distance runners present as a unique population in which to explore biomechanical phenomena in relation to running speed, as their training and racing spans a broad spectrum of paces. However, there have been no comprehensive investigations of running mechanics across speeds within this population. Here, we used the spring-mass model of running to explore global mechanical behavior across speeds in these runners. Ten elite-level 1500 m and mile runners (mean 1500 m best: 3:37.3 ± 3.6 s; mile: 3:54.6 ± 3.9 s) and ten highly trained 1500 m and mile runners (mean 1500 m best: 4:07.6 ± 3.7 s; mile: 4:27.4 ± 4.1 s) ran on a treadmill at 10 speeds where temporal measures were recorded. Spatiotemporal and spring-mass characteristics and their corresponding variation were calculated within and across speeds. All spatiotemporal measures changed with speed in both groups, but the changes were less substantial in the elites. The elite runners ran with greater approximated vertical forces (+ 0.16 BW) and steeper impact angles (+ 3.1°) across speeds. Moreover, the elites ran with greater leg and vertical stiffnesses (+ 2.1 kN/m and + 3.6 kN/m) across speeds. Neither group changed leg stiffness with increasing speeds, but both groups increased vertical stiffness (1.6 kN/m per km/h), and the elite runners more so (further + 0.4 kN/m per km/h). The elite runners also demonstrated lower variability in their spatiotemporal behavior across speeds. Together, these findings suggested that elite middle distance runners may have distinct global mechanical patterns across running speeds, where they behave as stiffer, less variable spring-mass systems compared to highly trained, but sub-elite counterparts.

scholarly journals Does Metabolic Rate Increase Linearly with Running Speed in all Distance Runners?

2017 ◽  
Vol 02 (01) ◽  
pp. E1-E8 ◽  
Author(s):  
Matthew Batliner ◽  
Shalaya Kipp ◽  
Alena Grabowski ◽  
Rodger Kram ◽  
William Byrnes
Keyword(s):  
Oxygen Uptake ◽  
Metabolic Rate ◽  
Perceived Exertion ◽  
Running Economy ◽  
Rating Of Perceived Exertion ◽  
Distance Runners ◽  
Cost Of Transport ◽  
Linear Relationships ◽  
Distance Running Performance ◽  
Elite Runners

AbstractRunning economy (oxygen uptake or metabolic rate for running at a submaximal speed) is one of the key determinants of distance running performance. Previous studies reported linear relationships between oxygen uptake or metabolic rate and speed, and an invariant cost of transport across speed. We quantified oxygen uptake, metabolic rate, and cost of transport in 10 average and 10 sub-elite runners. We increased treadmill speed by 0.45 m·s−1 from 1.78 m·s−1 (day 1) and 2.01 m·s−1 (day 2) during each subsequent 4-min stage until reaching a speed that elicited a rating of perceived exertion of 15. Average runners’ oxygen uptake and metabolic rate vs. speed relationships were best described by linear fits. In contrast, the sub-elite runners’ relationships were best described by increasing curvilinear fits. For the sub-elites, oxygen cost of transport and energy cost of transport increased by 12.8% and 9.6%, respectively, from 3.58 to 5.14 m·s−1. Our results indicate that it is not possible to accurately predict metabolic rates at race pace for sub-elite competitive runners from data collected at moderate submaximal running speeds (2.68–3.58 m·s−1). To do so, metabolic rate should be measured at speeds that approach competitive race pace and curvilinear fits should be used for extrapolation to race pace.

Effect of Hopping Frequency on Bilateral Differences in Leg Stiffness

2013 ◽  
Vol 29 (1) ◽  
pp. 55-60 ◽  
Author(s):  
Hiroaki Hobara ◽  
Koh Inoue ◽  
Kazuyuki Kanosue
Keyword(s):  
Ground Reaction Force ◽  
Center Of Mass ◽  
Reaction Force ◽  
Human Movement ◽  
Vertical Ground Reaction Force ◽  
Mass Model ◽  
Lower Extremity Injuries ◽  
Leg Stiffness ◽  
Significant Difference ◽  
Bilateral Differences

Understanding the degree of leg stiffness during human movement would provide important information that may be used for injury prevention. In the current study, we investigated bilateral differences in leg stiffness during one-legged hopping. Ten male participants performed one-legged hopping in place, matching metronome beats at 1.5, 2.2, and 3.0 Hz. Based on a spring-mass model, we calculated leg stiffness, which is defined as the ratio of maximal ground reaction force to maximum center of mass displacement at the middle of the stance phase, measured from vertical ground reaction force. In all hopping frequency settings, there was no significant difference in leg stiffness between legs. Although not statistically significant, asymmetry was the greatest at 1.5 Hz, followed by 2.2 and 3.0 Hz for all dependent variables. Furthermore, the number of subjects with an asymmetry greater than the 10% criterion was larger at 1.5 Hz than those at 2.2 and 3.0 Hz. These results will assist in the formulation of treatment-specific training regimes and rehabilitation programs for lower extremity injuries.

scholarly journals “(Self-)Surveillance, Anti-Doping, and Health in Non-Elite Road Running”

2013 ◽  
Vol 11 (4) ◽  
pp. 494-507 ◽  
Author(s):  
April D Henning
Keyword(s):  
Elite Athletes ◽  
Nutritional Supplements ◽  
Marathon Runner ◽  
Surveillance Systems ◽  
Disciplinary Power ◽  
Over The Counter ◽  
Surveillance Model ◽  
Elite Level ◽  
Performance Enhancing Drugs ◽  
Elite Runners

This article explores disciplining effects of current anti-doping surveillance systems on the health consequences of non-elites’ daily behaviors and habits. As they are left out of direct anti-doping testing and enforcement, it is tempting to argue non-elites are unaffected by anti-doping efforts focused on the elite level of their sport.  However, it is because they are not subject to anti-doping surveillance systems nor forced to comply with anti-doping regulations that non-elites are implicated within the wider arena of disciplinary power that envelops both elite and non-elite athletes and anti-doping agencies (Foucault 1979). Drawing on data from 28 interviews with non-elite runners I argue these runners do conform to the rules and norms of their sport as far as they understand them, but their knowledge of banned substances is inadequate and many non-elite runners have only a superficial and sometimes incorrect understanding of doping.  Many view doping and its associated health risks as a problem only of elite running, as well as a problem limited to only a handful of widely publicized performance enhancing drugs or doping methods.  As a result of these misunderstandings non-elite runners are vulnerable to negative health effects of over the counter (OTC) medications and nutritional supplements, which they view as “safe” and part of normal training as a result of the current elite surveillance model of anti-doping.  The recent death of a non-elite marathon runner linked to use of the unregulated energy supplement DMAA demonstrates, questionable products are used by runners who may not be fully aware of the risks of use.

scholarly journals Contemporary Nutrition Interventions to Optimize Performance in Middle-Distance Runners

2019 ◽  
Vol 29 (2) ◽  
pp. 106-116 ◽  
Author(s):  
Trent Stellingwerff ◽  
Ingvill Måkestad Bovim ◽  
Jamie Whitfield
Keyword(s):  
Muscle Glycogen ◽  
Point Of View ◽  
Glycolytic Flux ◽  
Fiber Morphology ◽  
Distance Runners ◽  
Nutrition Interventions ◽  
Nutritional Interventions ◽  
Intervention Point ◽  
Elite Level ◽  
Global Travel

Middle-distance runners utilize the full continuum of energy systems throughout training, and given the infinite competition tactical scenarios, this event group is highly complex from a performance intervention point of view. However, this complexity results in numerous potential periodized nutrition interventions to optimize middle-distance training adaptation and competition performance. Middle-distance race intensity is extreme, with 800- to 5,000-m races being at ∼95% to 130% of VO2max. Accordingly, elite middle-distance runners have primarily Type IIa/IIx fiber morphology and rely almost exclusively on carbohydrate (primarily muscle glycogen) metabolic pathways for producing adenosine triphosphate. Consequently, the principle nutritional interventions that should be emphasized are those that optimize muscle glycogen contents to support high glycolytic flux (resulting in very high lactate values, of >20 mmol/L in some athletes) with appropriate buffering capabilities, while optimizing power to weight ratios, all in a macro- and microperiodized manner. From youth to elite level, middle-distance athletes have arduous racing schedules (10–25 races/year), coupled with excessive global travel, which can take a physical and emotional toll. Accordingly, proactive and integrated nutrition planning can have a profound recovery effect over a long race season, as well as optimizing recovery during rounds of championship racing. Finally, with evidence-based implementation and an appropriate risk/reward assessment, several ergogenic aids may have an adaptive and/or performance-enhancing effect in the middle-distance athlete. Given that elite middle-distance athletes undertake ∼400 to 800 training sessions with 10–25 races/year, there are countless opportunities to implement various periodized acute and chronic nutrition-based interventions to optimize performance.

Is passive metatarsophalangeal joint stiffness related to leg stiffness, vertical stiffness and running economy during sub-maximal running?

2016 ◽  
Vol 49 ◽  
pp. 303-308 ◽  
Author(s):  
Hok Sum Man ◽  
Wing Kai Lam ◽  
Justin Lee ◽  
Catherine M. Capio ◽  
Aaron Kam Lun Leung
Keyword(s):  
Joint Stiffness ◽  
Metatarsophalangeal Joint ◽  
Running Economy ◽  
Vertical Stiffness ◽  
Leg Stiffness

Assessments of Mechanical Stiffness and Relationships to Performance Determinants in Middle-Distance Runners

2017 ◽  
Vol 12 (10) ◽  
pp. 1329-1334 ◽  
Author(s):  
Simon A. Rogers ◽  
Chris S. Whatman ◽  
Simon N. Pearson ◽  
Andrew E. Kilding
Keyword(s):  
Achilles Tendon ◽  
Plantar Flexion ◽  
Running Economy ◽  
Assessment Tools ◽  
Maximal Velocity ◽  
Mechanical Stiffness ◽  
Mass Model ◽  
Vertical Stiffness ◽  
Performance Determinants ◽  
Physiological Tests

Purpose: To examine relationships between methods of lower-limb stiffness and their associations with running economy (RE) and maximal velocity (vmax) in middle-distance (MD) runners. Methods: Eleven highly trained male MD runners performed a series of mechanical and physiological tests to determine maximal overground sprint speed, RE, and . Achilles tendon stiffness (kT) was estimated using ultrasonography during maximal isometric ankle plantar flexion. Global stiffness qualities were evaluated using a spring-mass model, providing measures of leg (kleg) and vertical stiffness (kvert) during running and jumping, respectively. Results: Very large (r = −.70) and large (r = −.60) negative relationships existed between RE and kT and kvert, during plantar flexion and unilateral jumps, respectively. There were large (r = .63) and extremely large (r = −.92) associations between kvert and kT and kleg during sprinting, respectively. Runners’ vmax had large positive associations between kT (r = .52) and kleg (r = .59) during sprinting. Conclusions: In well-trained MD athletes, greater stiffness appears linked to faster and more economical running. Although kT had the strongest relationship with RE, kleg while sprinting and kvert in maximal unilateral jumps may be more practical measures of stiffness. Agreement between global stiffness assessments and kT highlights the energy contribution of the Achilles tendon to running efficiency and velocity. Further research incorporating these assessment tools could help establish more comprehensive mechanical and metabolic athlete profiles and further our understanding of training adaptations, especially stiffness modification, longitudinally.

Effects of Fatigue on Running Mechanics: Spring-Mass Behavior in Recreational Runners After 60 Seconds of Countermovement Jumps

2015 ◽  
Vol 31 (6) ◽  
pp. 445-451 ◽  
Author(s):  
Gabriela Fischer ◽  
Jorge L.L. Storniolo ◽  
Leonardo A. Peyré-Tartaruga
Keyword(s):  
Center Of Mass ◽  
Force Plate ◽  
Vertical Displacement ◽  
Step Length ◽  
Vertical Force ◽  
Step Frequency ◽  
Mass Model ◽  
Vertical Stiffness ◽  
Recreational Runners ◽  
Running Mechanics

The purpose of this study was to investigate the effects of acute fatigue on spring-mass model (SMM) parameters among recreational runners at different speeds. Eleven participants (5 males and 6 females) performed running trials at slower, self-selected, and faster speeds on an indoor track before and after performing a fatigue protocol (60 s of countermovement jumps). Maximal vertical force (Fmax), impact peak force (Fpeak), loading rate (LR), contact time (Tc), aerial time (Ta), step frequency (SF), step length (SL), maximal vertical displacement of the center of mass (ΔZ), vertical stiffness (Kvert), and leg work (Wleg) were measured using a force plate integrated into the track. A significant reduction (–43.1 ± 8.6%; P < .05) in mechanical power during jumps indicated that the subjects became fatigued. The results showed that under fatigue conditions, the runners adjusted their running mechanics at slower (≈2.7 ms–1; ΔZ –12% and SF +3.9%; P < .05), self-selected (≈3.3 ms–1; SF +3%, SL –6.8%, Ta –16%, and Fmax –3.3%; P < .05), and faster (≈3.6 ms–1 SL –6.9%, Ta –14% and Fpeak –9.8%; P < .05) speeds without significantly altering Kvert (P > .05). During constant running, the previous 60 s of maximal vertical jumps induced mechanical adjustments in the spatiotemporal parameters without altering Kvert.

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