Teeter-totter effect: a new mechanism to understand shoe-related improvements in long-distance running

Nigg, Benno M.; Čigoja, Saša; Nigg, Sandro

doi:10.1136/bjsports-2020-102550

Cited by 48 publications

(49 citation statements)

References 6 publications

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“…These results challenge the recent suggestion that a curved plate alone can provide metabolic savings as high as 6% by acting as a teeter-totter 2,13 . The idea behind this suggested teeter-totter effect is that the curved plate would allow the foot and shoe to pivot during midstance to push-off in a way that the force applied at the front of the shoe results in a reaction force at the heel of the foot, and that this heel force would substantially improve running economy.…”

Section: Discussioncontrasting

confidence: 93%

“…The Nike Vaporfly 4% (VF) shoe utilizes both these technologies to give athletes up to 4% savings in running economy compared to two popular high-end marathon racing shoes 1,[7][8][9] , which translates to improved running performance 10,11 . While scientists and bloggers debate whether the foam 1,12 , geometry 3 , or curved carbon-fiber plate 2,13 contribute more to these 'super shoes', the exact mechanisms resulting in 4% metabolic savings are not yet understood.…”

Section: Introductionmentioning

confidence: 99%

“…However, an important limitation of that study is that the tested VF prototype shoes differed in both geometry (taller stack height), foam properties (more compliant and resilient) and LBS (stiffer; carbon-fiber plate) from the control shoes, once again making the contribution of the plate alone difficult to pinpoint. A recently introduced concept suggests that the curved plate may act like a teeter-totter and alone can result in up to 6% savings 2,13 , however, this unconfirmed concept originated based on pilot work and simulation data and has not been experimentally tested.…”

Section: Introductionmentioning

confidence: 99%

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Longitudinal bending stiffness does not affect running economy in Nike Vaporfly shoes

Healey¹,

Hoogkamer²

2021

Preprint

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Objectives: To determine the independent effect of the curved carbon-fiber plate in the Nike Vaporfly 4% shoe on running economy and running biomechanics.Methods: Fifteen healthy male runners completed a metabolic protocol and a biomechanics protocol. In both protocols participants wore two different shoe conditions, an intact Nike Vaporfly 4% (VFintact), and a cut Nike Vaporfly 4% (VFcut). The VFcut had 6 medio-lateral cuts through the carbon-fiber plate in the forefoot to reduce the effectiveness of the plate. In the metabolic protocol participants ran at 14 km/h for 5-minutes, twice with each shoe, on a force-measuring treadmill while breathing into an expired gas system. In the biomechanics protocol participants ran across a runway with embedded force plates at 14 km/h. We calculated running economy, kinetics, and joint mechanics of the lower limb.Results: Running economy did not significantly differ between shoe conditions (0.5% higher in the VFcut compared to the VFintact). Biomechanical differences were only found in the metatarsophalangeal joint (MTP) with increased MTP dorsiflexion angle, angular velocity, and negative power in the VFcut. Contact time was 1% longer in the VFcut.Conclusion: Cutting the carbon-fiber plate and reducing the longitudinal bending stiffness did not have a significant effect on the energy savings in the Nike Vaporfly 4%. This suggests that the plate alone plays a limited role in the 4% energy savings, and instead those likely result from a combination and interaction of the foam, geometry, and plate.

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Section: Discussioncontrasting

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Longitudinal bending stiffness does not affect running economy in Nike Vaporfly shoes

Healey¹,

Hoogkamer²

2021

Preprint

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“…With regards to rockers, the exact effect they have on running performance has not been quantified. Nigg et al [39] have suggested that the majority of metabolic savings in Vaporfly shoes come from a so-called teeter-totter effect, but this mechanism has not be fully defined or experimentally verified. Regardless, a rocker can be expected to improve the midfoot to toe off transition and combined with the right bending stiffness, reduce ankle plantar flexion moments (and associated plantar flexion muscle force demands) [40].…”

Section: Geometrymentioning

confidence: 99%

Can we quantify the benefits of “super spikes” in track running?

Healey¹,

Bertschy²,

Kipp³

et al. 2021

Preprint

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The recent and rapid developments in track spike innovation have been followed by a wave of record-breaking times and top performances. This has led many to question what role ‘super spikes’ play in improving running performance. To date, the specific contributions of new innovations, including lightweight, resilient, and compliant midsole foam, altered geometry, and increased longitudinal bending stiffness, to track running performance are unknown. Based on current literature, we speculate about what mechanical advantages these features may provide. Importantly, the effects of super spikes will vary based on several factors including the event-specific speed (i.e. 100 m vs. 10,000 m) and the characteristics of the athlete wearing them. Further confounding our understanding of super spikes is the difficulty of testing them. Unlike marathon shoes, testing track spikes comes with a unique challenge of quantifying the metabolic energy demands of mid-distance running events, which are partly anaerobic. For this reason, putting an exact number on the benefits from super spikes is difficult.

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“…Although the underlaying mechanisms of improved performance when running in footwear with increased MBS are not well understood, multiple effects were proposed: (1) minimising energy loss at the MTP joint 7 , (2) storing and returning elastic energy to the athlete 12 , 13 , (3) the ‘teeter-totter’ effect 14 , 15 , and (4) optimising the force–velocity profile of the ankle plantarflexor muscles 16 – 18 . In brief, the principle of minimising energy loss suggests that athletic improvements can be achieved by reducing the energy absorbed at joints due to less eccentric work performed by muscles crossing these joints.…”

Section: Introductionmentioning

confidence: 99%

Increasing the midsole bending stiffness of shoes alters gastrocnemius medialis muscle function during running

Čigoja

Fletcher

Esposito

et al. 2021

Sci Rep

Self Cite

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In recent years, increasing the midsole bending stiffness (MBS) of running shoes by embedding carbon fibre plates in the midsole resulted in many world records set during long-distance running competitions. Although several theories were introduced to unravel the mechanisms behind these performance benefits, no definitive explanation was provided so far. This study aimed to investigate how the function of the gastrocnemius medialis (GM) muscle and Achilles tendon is altered when running in shoes with increased MBS. Here, we provide the first direct evidence that the amount and velocity of GM muscle fascicle shortening is reduced when running with increased MBS. Compared to control, running in the stiffest condition at 90% of speed at lactate threshold resulted in less muscle fascicle shortening (p = 0.006, d = 0.87), slower average shortening velocity (p = 0.002, d = 0.93) and greater estimated Achilles tendon energy return (p ≤ 0.001, d = 0.96), without a significant change in GM fascicle work (p = 0.335, d = 0.40) or GM energy cost (p = 0.569, d = 0.30). The findings of this study suggest that running in stiff shoes allows the ankle plantarflexor muscle–tendon unit to continue to operate on a more favourable position of the muscle’s force–length–velocity relationship by lowering muscle shortening velocity and increasing tendon energy return.

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Teeter-totter effect: a new mechanism to understand shoe-related improvements in long-distance running

Cited by 48 publications

References 6 publications

Longitudinal bending stiffness does not affect running economy in Nike Vaporfly shoes

Longitudinal bending stiffness does not affect running economy in Nike Vaporfly shoes

Can we quantify the benefits of “super spikes” in track running?

Increasing the midsole bending stiffness of shoes alters gastrocnemius medialis muscle function during running

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