The Big Toe: Mechanical and Sensory Contributions to Propulsion in Sport Performance

In sport performance, considerable attention is devoted to how force is generated, transmitted and expressed. Coaches and practitioners discuss hip extension, tendon stiffness, ground reaction forces, projection angles and elastic energy storage. One of the structures most directly involved in transmitting force to the ground, the hallux or big toe, is discussed less often, and it is usually considered in the context of gait mechanics, injury prevention or clinical rehabilitation.

The hallux may nevertheless have a broader role in athletic movement than this limited view suggests. It is the last segment of the foot to leave the ground during push-off, it forms part of the lever through which the leg muscles act on the ground, and it is one of the regions where load, pressure and shear are transmitted between athlete and surface. Understanding its contribution therefore involves considering how sensory input, neural control, stiffness regulation and propulsion interact.

The Mechanical Role of the Big Toe

The classic description of hallux function centres on the first metatarsophalangeal joint. During late stance, dorsiflexion of the hallux tensions the plantar aponeurosis, the medial longitudinal arch rises and the foot becomes more resistant to deformation, a mechanism described as the windlass mechanism (Hicks, 1954). Foot stiffness is greatest in the “high gear” push-off, when the forefoot is pronated relative to the rearfoot and the plantar aponeurosis is tightened (Bojsen-Møller, 1979).

As the big toe dorsiflexes in late stance, the plantar aponeurosis tightens and the arch stiffens — the windlass mechanism (Hicks, 1954).

This account is useful but incomplete. The plantar fascia is not inextensible: high-speed radiographic data from running indicate that it stretches after foot contact and shortens later in stance, and that toe dorsiflexion delays part of this stretch, so the windlass operates alongside elastic recoil of the arch (Welte et al., 2021). The arch itself stores and returns a measurable share of the mechanical energy of each step (Ker et al., 1987). The metatarsophalangeal joint also behaves differently from the ankle in this respect. Inverse dynamics analyses of running and sprinting show that the joint absorbs energy, approximately 21 J in running and 48 J in sprinting in one sample of trained athletes, with little energy generation at take-off (Stefanyshyn and Nigg, 1997). The hallux and its joint therefore appear to contribute mainly by stabilising the forefoot and transmitting the forces produced proximally, rather than by generating propulsive work directly. In line with this, seven weeks of heavy resistance training of the toe flexors increased toe flexor strength and horizontal jump distance in young men (Goldmann et al., 2013), which suggests that the capacity of this region to withstand load may be relevant to performance.

An Evolutionary Perspective

The adducted, in-line position of the human hallux, distinct from the divergent big toe of non-human apes, is considered part of the transition to habitual bipedal locomotion (Harcourt-Smith and Aiello, 2004).

One of the distinguishing features of the human foot is the adducted position of the hallux, aligned with the other digits, whereas non-human apes retain a more divergent hallux that supports grasping. Reviews of the fossil and comparative evidence describe this change, together with the development of the longitudinal arch, as part of the transition to habitual bipedal locomotion (Harcourt-Smith and Aiello, 2004). Studies of the more mobile foot of the gibbon indicate that a compliant foot is less effective for push-off than a rigid, arched foot, although it can still contribute to propulsion through elastic recoil of tendons and ligaments (Vereecke and Aerts, 2008). Incorporation of the hallux into the medial forefoot is consistent with progression of the centre of pressure toward the first ray during late stance, although this is best documented through plantar pressure measurements in individual athletes.

Anatomical Features Relevant to Propulsion

The skeleton of the hallux consists of a proximal and a distal phalanx articulating with the first metatarsal. Two sesamoid bones lie beneath the first metatarsal head within the tendons of flexor hallucis brevis, where they are thought to distribute plantar load and to increase the moment arm of the flexor apparatus. Flexor hallucis brevis acts mainly at the metatarsophalangeal joint, whereas flexor hallucis longus acts on the interphalangeal joint and also contributes to plantarflexion and to support of the medial arch. The abductor and adductor hallucis, together with extensor hallucis longus and brevis, contribute to positioning and stabilisation of the toe in the frontal and sagittal planes. Tension in the plantar aponeurosis increases as the hallux dorsiflexes, which raises arch stiffness in the manner described above (Hicks, 1954; Welte et al., 2021).

"The hallux may nevertheless have a broader role in athletic movement than this limited view suggests. It is the last segment of the foot to leave the ground during push-off, it forms part of the lever through which the leg muscles act on the ground, and it is one of the regions where load, pressure and shear are transmitted between athlete and surface."

Sensory Contribution of the Foot Sole and Hallux

The plantar skin contains low-threshold mechanoreceptors that respond to pressure, vibration and skin deformation. Microneurographic recordings from the tibial nerve identified four classes of afferent in the glabrous skin of the foot sole, corresponding to fast-adapting and slow-adapting units of types I and II, and fast-adapting type I units were the most frequent (Kennedy and Inglis, 2002). The same study reported that receptors were widely distributed across the foot sole without an accumulation in the toes. The available evidence therefore supports a sensory role for the plantar surface as a whole, and it does not indicate that the hallux is more densely innervated than other regions. The hallux may nevertheless be of particular interest because it is heavily loaded at the end of stance, when the direction of the propulsive force is being finalised.

Cutaneous input from the foot sole contributes to balance control and to the regulation of walking. Experimental anaesthesia of the foot sole alters the pattern of joint torques used to respond to balance perturbations (Meyer, Oddsson and De Luca, 2004), vibration applied to different plantar regions produces shifts of the centre of pressure that depend on the area stimulated (Kavounoudias, Roll and Roll, 1998), and reviews of single-unit recordings describe the foot sole as a sensory structure relevant to postural control and gait (Strzalkowski et al., 2018). Proprioceptive signals from muscles and tendons acting on the toes are likely to complement cutaneous information (Proske and Gandevia, 2012). Most of this evidence concerns balance and walking, and studies specific to the hallux during sprinting or jumping appear to be limited. One exception is a laboratory study of fifteen participants in which lower vibration thresholds at the hallux were associated with higher peak pressures under the hallux, both in walking and in running (Nurse and Nigg, 1999). This correlational finding in a small sample does not establish that sensitivity determines loading, but it is consistent with a relationship between how the hallux is loaded and the information it provides.

Mechanoreceptors in the plantar skin are distributed across the whole sole rather than concentrated in the toes, but the hallux is heavily loaded at the point in stance where propulsive direction is finalised (Kennedy and Inglis, 2002; Nurse and Nigg, 1999).

Neural Pathways and Sensorimotor Integration

The plantar aspect of the hallux is supplied mainly by branches of the medial plantar nerve, a division of the tibial nerve. On the dorsal surface, the medial dorsal cutaneous branch of the superficial fibular nerve supplies most of the hallux, whereas the deep fibular nerve supplies the skin of the first web space between the hallux and the second toe. Afferent signals travel to the spinal cord and are distributed to spinal circuits and to supraspinal areas, including the somatosensory cortex, cerebellum and brainstem. Cutaneous reflexes in the lower limb are modulated according to the phase of the step cycle and the task, which indicates that sensory information is used continuously during locomotion and not only after a movement has been completed (Zehr and Stein, 1999).

Predictive Control and Movement Variability

At sprinting speeds, ground contact lasts a fraction of a second, so movement is likely to depend to a large extent on feedforward control based on previous sensory experience, with feedback contributing to adjustments from step to step. Experimental work on arm movements supports the proposal that the central nervous system uses an internal model that combines predictions of the consequences of a movement with incoming sensory information (Wolpert, Ghahramani and Jordan, 1995), although the extent to which this applies to the foot has not been established. It is plausible that plantar information, including that from the hallux, contributes to the calibration of these movement solutions over many repetitions. This idea remains a hypothesis, since direct evidence for a hallux-specific role in predictive control in athletes is limited. It may nonetheless help to explain why some interventions that modify plantar sensory input appear to influence locomotor behaviour without measurable changes in strength or range of motion.

Consistency in skilled movement is generally achieved through adaptable variability and not through repetition of identical patterns. Every sprint, jump or change of direction involves small differences in surface properties, fatigue and body position, and successful athletes adjust to them. Contemporary accounts of motor control describe movement as emerging from the interaction of many elements, with variability that does not affect the task outcome being useful for coping with perturbations (Latash, 2012). Step-to-step changes in hallux loading may be one of the ways in which such adjustments are informed, although this has not been examined directly.

Stiffness Regulation and the Distribution of Propulsion

Stiffness of the lower limb is not only a property of tissue. It depends on the mechanical behaviour of structures such as the plantar aponeurosis and the Achilles tendon and on the activation of muscles including the intrinsic foot muscles, tibialis posterior, soleus and gastrocnemius. Hallux dorsiflexion contributes to the mechanical component through the windlass mechanism. The foot also contains muscles that can modify this behaviour: in vivo loading of the arch has shown that flexor digitorum brevis, an intrinsic muscle spanning the arch, contracts approximately isometrically and increases the elastic energy stored in its tendon, which led the authors to propose that the central nervous system can actively adjust the mechanical and energetic properties of the foot (Kelly et al., 2018). The intrinsic muscles have also been described as a stabilising system of the arch (McKeon et al., 2015). A neural contribution, in which hallux afferent input helps to tune the activation of these and other lower limb muscles, is plausible on the basis of the reflex literature (Zehr and Stein, 1999) but has not, to my knowledge, been demonstrated specifically for the hallux.

Propulsion is likewise the product of several interacting components, including sensory, neural, muscular, fascial and skeletal structures, so that a change in hallux loading may influence foot stiffness, foot stiffness may influence ankle behaviour, and ankle mechanics may in turn affect force transmission through the lower limb. These influences are unlikely to follow a simple linear sequence, and the hallux is probably better regarded as one component within the wider locomotor network than as the end point of a kinetic chain.

Hallux Alignment and Performance

Conditions such as hallux valgus may alter the distribution of loading, first-ray function and the efficiency of the windlass mechanism. In a cross-sectional study of 120 community-dwelling adults, greater severity of hallux valgus was associated with lower peak pressure and maximum force under the hallux during walking, and the association was strongest in participants who reported pain at the great toe (Clarke et al., 2020). In young athletes with moderate or severe hallux valgus, a smaller cross-sectional study reported higher forefoot and midfoot loading than in athletes without the condition (Sarika and Sadhnani, 2024). These observational findings come mainly from walking and indicate that loading is redistributed around the deformity, without showing the effect on sprinting or jumping. Changes in joint position may also modify how plantar tissues are loaded and therefore how mechanoreceptors are stimulated, so alignment could influence the transmission of information as well as of force. This second possibility has received little direct study. Reduced propulsion in an athlete with altered hallux alignment may therefore reflect strength limitations, mechanical factors, differences in sensory input, or a combination of these.

"Propulsion is likewise the product of several interacting components, including sensory, neural, muscular, fascial and skeletal structures, so that a change in hallux loading may influence foot stiffness, foot stiffness may influence ankle behaviour, and ankle mechanics may in turn affect force transmission through the lower limb."

Implications for Sprint Performance

Sprinting places high demands on stiffness regulation, force orientation and sensorimotor control, and ground contact times are short. Within this context, the hallux may contribute by supporting formation of a stiff forefoot lever during late stance, by helping to transmit force into the ground, and possibly by providing information on the magnitude and direction of loading. The available mechanical evidence indicates that its contribution to net propulsive work is limited (Stefanyshyn and Nigg, 1997), so its importance is more likely to relate to how the forces produced by the larger proximal muscles are organised and transmitted.

Implications for Assessment and Training

Assessments of the foot commonly address strength, mobility, pain and alignment. Practitioners may also find it useful to observe how the hallux is used during dynamic tasks, for example whether pressure progresses toward the first ray during propulsion, whether hallux loading is maintained during acceleration, whether the athlete relies on compensatory toe strategies and whether this changes under fatigue. Validated field methods for these observations are limited, and plantar pressure systems or video analysis may provide supporting information. Interpretation also benefits from considering that a similar observation, such as reduced loading under the hallux, may arise from different sources, including pain, restricted first metatarsophalangeal motion, weakness of the toe flexors, altered alignment or a change in the information available to the athlete, as suggested by the association between hallux loading and pain in hallux valgus (Clarke et al., 2020). Each source may call for a different intervention, and the response is best examined at the foot, the ankle and the whole limb, since a local change may be redistributed elsewhere in the movement pattern.

Training may target strength of the toe flexors, since this capacity responds to heavy loading within a few weeks (Goldmann et al., 2013), while also including tasks in which plantar sensory information is relevant, such as barefoot or varied-surface work. The purpose is not solely to increase toe strength but to improve how the foot behaves as part of the whole movement, and the effects of such programmes on sprint performance require further study.

Conclusion

The hallux contributes to propulsion mechanically, through the windlass mechanism, arch stiffness and force transmission, and it is likely to contribute through the sensory information generated at the foot sole. Its role in net propulsive work appears limited, and several of the neural contributions discussed here, including those to predictive control and stiffness regulation, remain hypotheses that need direct testing in athletic populations. For practitioners working in sprinting, jumping, multidirectional sport and rehabilitation, the hallux offers a useful reminder that performance is explained by the interaction of anatomy, sensory information, neural organisation and movement behaviour and not by any single structure.

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Frequently Asked Questions

Q: What is the windlass mechanism and how does it involve the big toe? 

When the hallux dorsiflexes during late stance, the plantar aponeurosis is tensioned around the first metatarsal head, the arch rises and the foot becomes stiffer (Hicks, 1954). Recent imaging indicates that the plantar fascia also stretches and recoils during running, so the windlass appears to operate together with elastic recoil of the arch (Welte et al., 2021).

Q: Does the big toe generate propulsive energy in sprinting? 

Available inverse dynamics data suggest that the metatarsophalangeal joint mainly absorbs energy during running and sprinting, with little generation at take-off (Stefanyshyn and Nigg, 1997). Its contribution seems to relate mainly to stabilising the forefoot and transmitting force from the proximal muscles.

Q: Can toe flexor strength be trained, and does it influence performance? 

Seven weeks of heavy resistance training increased toe flexor strength and horizontal jump distance in young men (Goldmann et al., 2013). Evidence for sprint performance specifically is more limited, so the effect may depend on the task and the population.

Q: Is the big toe more sensitive than the rest of the foot sole? 

Microneurographic recordings did not show an accumulation of mechanoreceptors in the toes (Kennedy and Inglis, 2002). The sensory role therefore appears to belong to the foot sole as a whole, although the hallux is heavily loaded at the end of stance and, in a small study, hallux vibration thresholds were associated with peak hallux pressure (Nurse and Nigg, 1999).

Q: Can hallux alignment affect athletic movement? 

Conditions such as hallux valgus may alter loading, first-ray function and windlass efficiency, and they could also change plantar sensory input. Direct evidence for effects on sprint or jump performance is limited, so individual assessment remains important.

References

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• Clarke, G.R., Thomas, M.J., Rathod-Mistry, T., Marshall, M., Menz, H.B., Peat, G. and Roddy, E. (2020) ‘Hallux valgus severity, great toe pain, and plantar pressures during gait: a cross-sectional study of community-dwelling adults’, Musculoskeletal Care, 18(3), pp. 383-390.

• Goldmann, J.-P., Sanno, M., Willwacher, S., Heinrich, K. and Brüggemann, G.-P. (2013) ‘The potential of toe flexor muscles to enhance performance’, Journal of Sports Sciences, 31(4), pp. 424-433.

• Harcourt-Smith, W.E.H. and Aiello, L.C. (2004) ‘Fossils, feet and the evolution of human bipedal locomotion’, Journal of Anatomy, 204(5), pp. 403-416.

• Hicks, J.H. (1954) ‘The mechanics of the foot. II. The plantar aponeurosis and the arch’, Journal of Anatomy, 88(1), pp. 25-30.

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• Kennedy, P.M. and Inglis, J.T. (2002) ‘Distribution and behaviour of glabrous cutaneous receptors in the human foot sole’, Journal of Physiology, 538(3), pp. 995-1002.

• Ker, R.F., Bennett, M.B., Bibby, S.R., Kester, R.C. and Alexander, R.McN. (1987) ‘The spring in the arch of the human foot’, Nature, 325(7000), pp. 147-149.

• Kelly, L.A., Farris, D.J., Cresswell, A.G. and Lichtwark, G.A. (2018) ‘Intrinsic foot muscles contribute to elastic energy storage and return in the human foot’, Journal of Applied Physiology, 126(1), pp. 231-238.

• Latash, M.L. (2012) ‘The bliss (not the problem) of motor abundance (not redundancy)’, Experimental Brain Research, 217(1), pp. 1-5.

• McKeon, P.O., Hertel, J., Bramble, D. and Davis, I. (2015) ‘The foot core system: a new paradigm for understanding intrinsic foot muscle function’, British Journal of Sports Medicine, 49(5), p. 290.

• Meyer, P.F., Oddsson, L.I.E. and De Luca, C.J. (2004) ‘Reduced plantar sensitivity alters postural responses to lateral perturbations of balance’, Experimental Brain Research, 157(4), pp. 526-536.

• Nurse, M.A. and Nigg, B.M. (1999) ‘Quantifying a relationship between tactile and vibration sensitivity of the human foot with plantar pressure distributions during gait’, Clinical Biomechanics, 14(9), pp. 667-672.

• Proske, U. and Gandevia, S.C. (2012) ‘The proprioceptive senses: their roles in signaling body shape, body position and movement, and muscle force’, Physiological Reviews, 92(4), pp. 1651-1697.

• Sarika and Sadhnani, A. (2024) ‘Evaluation and comparison of plantar pressure distribution and gait parameters in athletes with and without hallux valgus’, The Foot, 60, 102120.

• Stefanyshyn, D.J. and Nigg, B.M. (1997) ‘Mechanical energy contribution of the metatarsophalangeal joint to running and sprinting’, Journal of Biomechanics, 30(11-12), pp. 1081-1085.

• Strzalkowski, N.D.J., Peters, R.M., Inglis, J.T. and Bent, L.R. (2018) ‘Cutaneous afferent innervation of the human foot sole: what can we learn from single-unit recordings?’, Journal of Neurophysiology, 120(3), pp. 1233-1246.

• Vereecke, E.E. and Aerts, P. (2008) ‘The mechanics of the gibbon foot and its potential for elastic energy storage during bipedalism’, Journal of Experimental Biology, 211(23), pp. 3661-3670.

• Welte, L., Kelly, L.A., Kessler, S.E., Lieberman, D.E., D’Andrea, S.E., Lichtwark, G.A. and Rainbow, M.J. (2021) ‘The extensibility of the plantar fascia influences the windlass mechanism during human running’, Proceedings of the Royal Society B, 288(1943), 20202095.

• Wolpert, D.M., Ghahramani, Z. and Jordan, M.I. (1995) ‘An internal model for sensorimotor integration’, Science, 269(5232), pp. 1880-1882.

• Zehr, E.P. and Stein, R.B. (1999) ‘What functions do reflexes serve during human locomotion?’, Progress in Neurobiology, 58(2), pp. 185-205.

Antonio Robustelli is the founder of Omniathlete. He is an international high performance consultant and sought-after speaker in the area of Sport Science and Sports Medicine, working all over the world with individual athletes (including participation in the last 5 Olympics) as well as professional teams in soccer, basketball, rugby, baseball since 24 years. Currently serving as Faculty Member and Programme Leader at the National Institute of Sports in India (SAI-NSNIS).