## 1 Introduction  
Different habits (such as frequency of sport activity and shoe wearing practices), and individual characteristics (such as sex, body mass index, and age), are related to adult foot morphology [1]. Human foot shape also differs among ethnic groups [2] and changes over the course of postnatal development [3].  
Anthropometric studies have shown considerable sex differences in the foot bones [4]. In three-dimensional analyses, sex was associated with ankle width, Achilles tendon width, and heel width [5]. In contrast to males, females have greater generalized joint laxity following the onset of puberty [6]. Postpubescent athletes had greater knee anterior/posterior forces, as well as mediolateral resultant forces, after jumping [7].  
Research on footprint analysis during walking in two-dimensional analyses of data from an in-shoe pressure measurement system has been carried out. Sex was not significantly related to the peak pressure, contact time, pressure-time integral, and instant of peak pressure. The force-time integral, however, was significantly greater in males than females under the first, third, and fourth metatarsal heads [8]. The maximum force was also significantly higher in males under the heel [8] and the first and third metatarsal heads, and the mean force was greater in males under the third metatarsal head [8]. It should be noted that none of these variables were normalized to body weight or height. [PERSON] et al. [9] studied the plantar pressures in a standing position and found that females had significantly higher pressures in the heel than males. Several authors [8,10,11] observed that males had significantly larger contact areas in all regions of the foot than females. Other authors, in a sequence of footprints during a single gait cycle, called the dynamic footprint [12], found no differences [13].  
A functional equinus condition can be defined as \"dorsiflexion limitation of the ankle with the knee extended/flexed (excluding osseeous restriction)\" [13,14]. A functional equinus condition is a non-symptomatic condition, but its incidence is high. In a study of 209 consecutive patients with musculoskeletal problems in the foot, a prevalence of 96.5% of this condition was found and has been linked to foot problems including plantar fascitis and metataralsalgia [15]. It may promote clinical alterations in the Achilles tendon and triceps surae muscle [13]. Equinus is significantly related to lower limb injuries (e.g., anterior cruciate ligament rupture), asymmetric loading patterns, and alterations in triceps surae contraction [16]. In footwear, a prolonged or chronic use of high-heeled shoes can cause the Achilles tendon to become stiff and rigid [17]. A lack of adequate ankle dorsiflexion can result in compensation within the gait cycle, such as a near heel lift and an increase in forefoot pressures [18] Once the ankle is restricted, the midtarsal joint is the next joint through which dorsiflexion may occur [19]. This is achieved by excessive pronation of the foot [19]. The pronation of the midtarsal joint of the functional equinus condition and the postpubescent laxity of women are two factors that could increase the variable of the surface of the footprint. Therefore, it is necessary to check if ligamentous laxity is an agent that provides sex differences in this pathology.  
Gender differences in plantar footprint variables with functional Equinus have not been compared with a biomechanical approach for the first, second, and third steps. If they exist, they should be taken into consideration for the specific design of footwear by sex, especially in those situations with higher ground contact forces, such as sport. Our measurements were focused on the three stages of the stance phase: heel strike, mid-stance, and take off, in order to check sex differences. The main purpose of this study was to compare males and females in terms of surface variables for the first, second, and third walking steps with a pressure platform.