Our Joe Nimble model - Slingshot uses a strategically placed, partial solution that preserves and supports big-toe function.
Context
Records like those set in the Nike Vaporfly show this:
a very stiff full plate can extend lever arms and reduce energy losses at the elite level. It works — but it comes with trade-offs. For most runners, the priority isn’t the next personal best, but efficient, resilient running over years.
That requires toe room, active big-toe engagement, and a shoe construction that lets the foot’s natural spring do its job.
Continuous, very stiff plates restrict toe movement. When the toes can’t yield and actively contribute, the forefoot loses front-end stability, and the foot’s natural spring — the interplay of the arch, plantar fascia, toe joints, and the calf–Achilles complex — stores and returns less energy.
Push-off then shifts away from the big toe; you often roll more along the lateral edge or compensate in your gait. This can feel stiff and “fast” at first but loads the calves and Achilles asymmetrically, reduces control in corners or on uneven ground, and causes the feet to fatigue faster.
Over time, the risk of overuse issues increases because your foot is no longer allowed to function as an active spring.
What the research shows
Independent reviews and lab studies consistently report: increasing forefoot/sole stiffness can improve running economy in the short term, but it reduces toe joint mobility and shifts how work is distributed within the foot.
The effect depends strongly on the magnitude and placement of stiffness — applied selectively, it can support; as a continuous full plate, it tends to dampen natural functions [1–4].
Our approach
We adopt the principle of directing energy precisely without switching off natural function.ToeFreedom means:
space for the toes so they can grip, splay, and stabilize.
Big Toe First means:
propulsion through the big-toe area, i.e., the medial forefoot column.
That’s why we’re not fundamentally against carbon, but against rigid full plates. We support targeted, dynamic carbon solutions that deliver efficiency without promoting long-term issues.
That’s exactly why we designed the Slingshot: noticeable propulsion with preserved toe work — built for today and for many years of running.
Partial solution:
a precisely placed, non-continuous composite component supports force transfer in the big-toe area while keeping the toes mobile.
ToePilot® now with carbon fiber:
Integrated into every Slingshot midsole, it directs push-off where it belongs — through the big toe.
Carbitex® GearFlex:
It adapts to natural foot mechanics — initially compliant, then stiffening past a specific angle exactly at push-off. This delivers support with the right timing without blocking toe work prematurely.
- No full plate: Slingshot uses targeted, partial support instead of continuous stiffness.
- Built for durability: dynamic, selective carbon solutions that combine efficiency with long-term tolerance.
- Toes stay active: toefreedom and Big Toe First are preserved.
- Propulsion with timing: ToePilot® with Carbitex® stiffens only at push-off — noticeable support with natural foot function.
References
- McLeod AR, Bruening DA, Roper JL (2020) Forefoot bending stiffness, toe flexor mechanics, and running economy. Sports Medicine. https://link.springer.com/article/10.1007/s40279-020-01268-1
- Hébert Losier K et al. (2022) Effects of footwear forefoot bending stiffness on running biomechanics and economy: Systematic review. Footwear Science. https://www.tandfonline.com/doi/full/10.1080/19424280.2022.2040782
- Ortega JA, Healey LA (2020) Running economy with highly cushioned, stiff soled shoes. Sports Medicine. https://link.springer.com/article/10.1007/s40279-020-01353-2
- Day EM et al. (2022) The effect of shoe midsole bending stiffness on ankle and MTP joint mechanics. Preprint. https://doi.org/10.1101/2022.01.20.476770