ABSTRACT
Introduction/Purpose
Shoe longitudinal bending stiffness (LBS) is often considered to influence running economy (RE) and thus, running performance. However, previous results are mixed and ...LBS levels have not been studied in advanced footwear technology (AFT). The purpose of this study was to evaluate the effects of increased LBS from curved carbon fiber plates embedded within an AFT midsole compared to a traditional running shoe on RE and spatiotemporal parameters.
Methods
Twenty‐one male trained runners completed three times 4 min at 13 km/h with two experimental shoe models with a curved carbon fiber plate embedded in an AFT midsole with different LBS values (Stiff: 35.5 N/mm and Stiffest: 43.1 N/mm), and a Control condition (no carbon fiber plate: 20.1 N/mm). We measured energy cost of running (W/kg) and spatiotemporal parameters in one visit.
Results
RE improved for the Stiff shoe condition (15.71 ± 0.95 W/kg; p < 0.001; n2 = 0.374) compared to the Control condition (16.13 ± 1.08 W/kg; 2.56%) and Stiffest condition (16.03 ± 1.19 W/kg; 1.98%). However, we found no significant differences between the Stiffest and Control conditions. Moreover, there were no spatiotemporal differences between shoe conditions.
Conclusion
Changes in LBS in AFT influences RE suggesting that moderately stiff shoes have the most effective LBS to improve RE in AFT compared to very stiff shoes and traditional, flexible shoe conditions while running at 13 km/h.
Training, footwear, nutrition, and racing strategies (i.e., drafting) have all been shown to reduce the metabolic cost of distance running (i.e., improve running economy). However, how these ...improvements in running economy (RE) quantitatively translate into faster running performance is less established. Here, we quantify how metabolic savings translate into faster running performance, considering both the inherent rate of oxygen uptake-velocity relation and the additional cost of overcoming air resistance when running overground. We collate and compare five existing equations for oxygen uptake-velocity relations across wide velocity ranges. Because the oxygen uptake vs. velocity relation is non-linear, for velocities slower than ∼3 m/s, the predicted percent improvement in velocity is slightly greater than the percent improvement in RE. For velocities faster than ∼3 m/s, the predicted percent improvement in velocity is less than the percent improvements in RE. At 5.5 m/s, i.e., world-class marathon pace, the predicted percent improvement in velocity is ∼2/3rds of the percent improvement in RE. For example, at 2:04 marathon pace, a 3% improvement in RE translates to a 1.97% faster velocity or 2:01:36, almost exactly equal to the recently set world record.
Despite being an intricate part of advanced footwear technology, the impact of midsole thickness is not well understood. While some individuals have speculated an increased midsole thickness might ...bequeath an unfair performance advantage, others have suggested it may have a detrimental impact on frontal plane ankle stability. Therefore, the purpose of this study was to determine the influence of midsole thickness on running economy, and frontal plane ankle stability. Twenty one recreational runners (ten female, and eleven male) participated in this study, performing five-minute treadmill running trials in four footwear conditions. The footwear conditions were nearly identical except for their midsole thicknesses which ranged from 35- to 50-mm in increments of 5-mm. Midsole thickness was not found to influence the energetic cost of running however, it was found to decrease frontal plane ankle stability. Given these results World Athletic restrictions on midsole thickness may be unnecessary and worthy of reconsideration.
We evaluated (1) whether participating in middle- and long-distance running races augments muscle soreness, oxygen cost, respiration, and exercise exertion during subsequent running, and (2) if ...post-race menthol application alleviates these responses in long-distance runners.
Eleven long-distance runners completed a 1500-m race on day 1 and a 3000-m race on day 2. On day 3 (post-race day), either a 4% menthol solution (Post-race menthol) or a placebo solution (Post-race placebo) serving as a vehicle control, was applied to their lower leg skin, and their perceptual and physiological responses were evaluated. The identical assessment with the placebo solution was also conducted without race participation (No-race placebo).
The integrated muscle soreness index increased in the Post-race placebo compared to the No-race placebo (P < 0.001), but this response was absent in the Post-race menthol (P = 0.058). Oxygen uptake during treadmill running tended to be higher (4.3%) in the Post-race placebo vs. No-race placebo (P = 0.074). Oxygen uptake was 5.4% lower in the Post-race menthol compared to the Post-race placebo (P = 0.018). Minute ventilation during treadmill running was 6.7-7.6% higher in the Post-race placebo compared to No-race placebo, whereas it was 6.6-9.0% lower in the Post-race menthol vs. Post-race placebo (all P ≤ 0.001). The rate of perceived exertion was 7.0% lower in the Post-race menthol vs. Post-race placebo (P = 0.007).
Middle- and long-distance races can subsequently elevate muscle soreness and induce respiratory and metabolic stress, but post-race menthol application to the lower legs can mitigate these responses and reduce exercise exertion in long-distance runners.
There is scientific and legal controversy about recent technological advances in performance running shoes that reduce the energetic cost of running and may provide a distinct competitive advantage. ...To better understand the potential performance-enhancing effects of technological advancements in marathon racing shoes, we examined the finishing times and racing shoes of the top 50 male and 50 female runners from the World Marathon Major series in the 2010s - before and after the introduction of new Nike shoe models (4%, NEXT%, Alphafly, and other prototypes; herein referred to as neoteric Nikes). Data for racing shoes were available for 3,886 of the 3,900 performances recorded at the four annual marathons in Boston, London, Chicago, and New York. In full cohort analyses, marathon finishing times were 2.0% or 2.8 min (138.5±8.1 min vs. 141.3±7.4 min, P<0.001) faster for male runners wearing neoteric Nikes compared to other shoes. For females, marathon finishing times were 2.6% or 4.3 min (159.1±10.0 min vs. 163.4±10.7 min, P<0.001) faster for runners wearing neoteric Nikes. In a subset of within-runner changes in marathon performances (males, n = 138; females, n = 101), marathon finishing times improved by 0.8% or 1.2 min for males wearing neoteric Nikes relative to the most recent marathon in which other shoes were worn, and this performance-enhancing effect was greater among females who demonstrated 1.6% or 3.7 min improvement (P=0.002). Our results demonstrate that marathon performances are substantially when world-class athletes, and particularly females, wear marathon racing shoes with technological advancements.
The cost of generating force hypothesis proposes that the metabolic rate during running is determined by the rate of muscle force development (1/t
, t
=contact time) and the volume of active leg ...muscle. A previous study assumed a constant recruited muscle volume and reported that the rate of force development alone explained ∼70% of the increase in metabolic rate for human runners across a moderate velocity range (2-4 m s
). We hypothesized that over a wider range of velocities, the effective mechanical advantage (EMA) of the lower limb joints would overall decrease, necessitating a greater volume of active muscle recruitment. Ten high-caliber male human runners ran on a force-measuring treadmill at 8, 10, 12, 14, 16 and 18 km hr
while we analyzed their expired air to determine metabolic rates. We measured ground reaction forces and joint kinematics to calculate contact time and estimate active muscle volume. From 8 to 18 km hr
, metabolic rate increased 131% from 9.28 to 21.44 W kg
Contact time (t
) decreased from 0.280 sec to 0.190 sec, and thus the rate of force development (1/t
) increased by 48%. Ankle EMA decreased by 19.7±11%, knee EMA increased by 11.1±26.9% and hip EMA decreased by 60.8±11.8%. Estimated active muscle volume per leg increased 52.8% from 1663±152 cm
to 2550±169 cm
Overall, 98% of the increase in metabolic rate across the velocity range was explained by just two factors: the rate of generating force and the volume of active leg muscle.
•The number of years of running experience has a positive effect on running economy, but it is insufficient to overcome the negative effect of the aging process.•Running economy was significantly ...reduced in participants aged ≥60 years compared with that in younger athletes.
The maximum oxygen uptake (V˙O2max), the maximum rate of oxygen that can be sustained before the onset of blood lactate accumulation, and the metabolic cost of locomotion are the main physiological factors associated with long-distance running performance. The latter is known as the running economy. Generally, runners reach peak performance in long races between 25 and 30 years of age, with a progressive decline occurring thereafter. However, it is not known whether the running economy is affected or how it is affected by aging.
To investigate the effect of age and years of running experience on the running economy of amateur long-distance runners aged 20–80 years.
Sixty-nine recreational long-distance runners, divided into five age groups according to decade of life, participated in this study: Group 1 (n= 9) 27.2 ± 1.3 years, Group 2 (n= 18) 35.9 ± 2.2 years, Group 3 (n= 17) 43.4 ± 2.8 years, Group 4 (n= 17) 53.0 ± 2.3 years, and Group 5 (n= 8) 65.5 ± 2.9 years. For running economy assessment, oxygen cost (OC) and energy cost (EC) were measured. Furthermore, the participants were interviewed on their running experience.
For EC, the two independent variables composing the regression model were age (ß = 0.703, t= 5.443, p < 0.001) and running experience (ß = −0.230, t = −1.785, p= 0.07), and 34% of the energy cost variation can be explained by these two factors. EC and OC were compared among the groups. There were no significant differences between Groups 1 and 2 (p= 0.999), Groups 1 and 3 (p= 1.000), and Groups 1 and 4 (p= 0.528). However, Group 5 had a significantly higher energy cost than Group 1 (p < 0.001), Group 2 (p < 0.001), Group 3 (p < 0.001) and Group 4 (p < 0.001).
The number of years of running experience has a positive effect on running economy, but it is insufficient to overcome the negative effect of the aging process. Furthermore, running economy was significantly worse in participants aged ≥60 years compared with that in younger athletes.
Introduction
Modern running shoes have revolutionized long-distance performances by decreasing the amount of oxygen athletes need when running at a given speed, which is termed running economy. In ...2022, World Athletics imposed an upper limit of 40 mm for midsole thickness, possibly to prevent shoes from having an overemphasized role in performance. This ceiling, however, seems arbitrary, and a better understanding of whether midsole thickness affects running economy is needed. This study therefore investigated if midsole thickness affects oxygen consumption both indoors and outdoors, as early findings from treadmill studies may not translate to overground running.
Methods
Following a familiarization trial including an incremental test, 16 well-trained male runners (weight 70 ± 6 kg, age 28 ± 5 years, peak oxygen uptake, V̇O2peak 64 ± 4 ml O2･kg-1･min-1, peak running speed 20.0 ± 0.8 km･h-1) completed two testing visits, once on a treadmill and once on a track, each consisting of twelve 5-min runs at submaximal speed (16 km･h-1) alternating three different footwear conditions: an entry-level running shoe (EL, 30 mm midsole thickness) and two carbon-plated modern running shoes with midsole thickness of 40 and 50 mm, respectively. The shoe order was randomized and balanced between each of the four replicates. Gas exchange and heart rate were continuously measured throughout the runs.
Results
Running with 40 mm shoes reduced V̇O2 compared with EL shoes by 2.4 ± 1.1% on the treadmill and 4.0 ± 1.2% when running overground (both p < 0.001). Running with 50mm shoes also decreased V̇O2 compared with EL shoes both on the treadmill (-2.7 ± 1.6%, p < 0.001) and overground (-4.6 ± 1.8%, p < 0.001), but no differences were detected between the modern shoes (40 mm vs. 50 mm treadmill: +0.3 ± 1.3%, p = 0.586; overground: +0.6 ± 1.4%, p = 0.189). Similarly, heart rate was lower compared with the EL shoes in both the 40 mm shoes (treadmill -1.3 ± 0.6%; overground -2.0 ± 0.6%; both p < 0.001) and 50 mm shoes (treadmill -1.6 ± 0.7%; overground -2.3 ± 0.6%, both p < 0.001), but no differences were detected between the modern shoes (40 mm vs. 50 mm treadmill: +0.3% ± 0.6%, p = 0.106; overground: +0.4 ± 0.6%, p = 0.090). Interestingly when running overground V̇O2 decreased over time for the 50 mm shoes, reaching significance between replicates 1 and 4 (p = 0.017), which was not the case for the 40 mm shoes (p = 0.817). The V̇O2 ratio between the 50 mm and 40 mm shoes was 1.003 in replicate 1 and 0.987 in replicate 4 (p = 0.108).
Discussion/Conclusion
Our data suggests that a 50 mm midsole does not offer significant benefits compared with race-legal 40 mm midsole shoes when tested over short durations. The 50 mm shoes cause a noticeable decrease in V̇O2 over time when used outdoors, which may reflect a learning effect to this unfamiliar midsole thickness. Longer test sessions may be necessary to reveal the actual impact on running economy of shoes with over 40 mm midsoles.
The study aimed to investigate the effect of flywheel accentuated eccentric loading (AEL) training on the running economy (RE) of young male well-trained distance runners. Twenty-two runners ...participated and were randomly assigned to the flywheel (FG,
= 12) and the control group (CG,
= 10). Traditional endurance training was performed in both groups three times a week for 6-week, while traditional resistance and flywheel AEL training was added to the CG and FG respectively. Subjects performed the incremental exercise test, squat jump, and countermovement jump (CMJ) before and after training. The results showed that 1) the RE at 65% of peak oxygen consumption (VO
peak), 75% VO
peak, and 85% VO
peak improved significantly after 6 weeks of training (
< 0.01, Effect size (ES) = 0.76;
< 0.01, ES = 1.04;
< 0.01, ES = 1.85) in FG, and the RE of 85% VO
peak in FG was significantly lower than CG (
< 0.05, ES = 0.30); 2) in post-training, both squat jump (
< 0.01, ES = 0.73) and CMJ (
< 0.01, ES = 1.15) performance, eccentric utilization ratio (
< 0.04, ES = 0.44), the rate of force development (RFD) of squat jump (
< 0.05, ES = 0.46), and CMJ
(
< 0.01, ES = 0.66) were significantly improved in FG. And there are no significant differents in CG group because it was maintain training for our participants. Our findings showed that 1) flywheel AEL training improves the muscles' explosive strength and other neuromuscular functions, and improves the athlete's running economy under 65%, 75%, and 85% VO
peak, which potentially increases endurance performance. 2) Flywheel AEL training can improve the height, RFD, and the eccentric utilization ratio of squat jump and CMJ, and other lower limb elastic potential energy indicators of the young male, well-trained distance runners.
PURPOSETo investigate the joint-specific contributions to the total lower-extremity joint work during a prolonged fatiguing run.
METHODSRecreational long-distance runners (n = 13) and competitive ...long-distance runners (n = 12) performed a 10-km treadmill run with near-maximal effort. A three-dimensional motion capture system synchronized with a force-instrumented treadmill was used to calculate joint kinetics and kinematics of the lower extremity in the sagittal plane during the stance phase at 13 distance points over the 10-km run.
RESULTSA significant (P < 0.05) decrease of positive ankle joint work as well as an increase of positive knee and hip joint work was found. These findings were associated with a redistribution of the individual contributions to total lower-extremity work away from the ankle toward the knee and hip joint which was more distinctive in the recreational runner group than in the competitive runner group. This redistribution was accomplished by significant (P < 0.05) reductions of the external ground-reaction force lever arm and joint torque at the ankle and by the significant (P < 0.05) increase of the external ground-reaction force lever arm and joint torque at the knee and hip.
CONCLUSIONSThe redistribution of joint work from the ankle to more proximal joints might be a biomechanical mechanism that could partly explain the decreased running economy in a prolonged fatiguing run. This might be because muscle–tendon units crossing proximal joints are less equipped for energy storage and return compared with ankle plantar flexors and require greater muscle volume activation for a given force. To improve running performance, long-distance runners may benefit from an exercise-induced enhancement of ankle plantar flexor muscle–tendon unit capacities.
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