Introduction The role of goalkeepers in soccer requires rapid, precise movements that combine explosive strength with finely tuned neuromuscular coordination. Although previous studies [1,2] have examined diving techniques using force platforms and optical motion capture, they lack detailed insight into how forces are distributed across different regions of the foot during a dive. To address this gap, we investigated plantar pressure distribution and lower-limb kinematics in an elite female goalkeeper performing low-corner dives, using wearable inertial sensors and sensorized pressure insoles. Methods An 18-year-old goalkeeper from an elite youth team performed four randomized low dives (two per side) intercepting balls launched at approximately 30 cm height and 70 cm from the post. Kinematic data were recorded at 60 Hz with the Xsens MVN Biomech Link system (17 IMUs) and plantar pressures at 100 Hz using XSENSOR® smart insoles. A distinctive foot-strike acceleration peak was used as a synchronization marker across all devices. Time series were normalized from peak hip flexion to ipsilateral foot take-off, and analysis focused on stance width (normalized to leg length), joint angles (hip, knee, ankle), vertical ground reaction forces, and regional plantar pressures at four key instants: preparatory phase, ipsilateral foot initial contact (IFIC), contralateral peak force (CPF), and ipsilateral peak force (IPF). Given the exploratory nature and small sample size, data are presented descriptively without inferential statistics. Results During the preparatory phase (0% of the movement), the total vertical ground reaction force was about 640 N and evenly distributed. Peak pressures occurred under the metatarsals (≈ 136 N) and toes (≈ 126 N). Stance width was 44% of the leg length. Hip flexion measured 105°, knee flexion 59°, and ankle dorsiflexion 17°. At initial foot contact (IFIC; ~48% of the movement phase), contralateral force increased to 341 N. The load shifted toward the midfoot and metatarsals. Stance width increased to 56%. Hip flexion dropped to 93°, and ankle dorsiflexion to 11°.At contralateral peak force (CPF; ~76%), vertical force under the forefoot peaked at 470 N. Stance width reached 84%, and ankle dorsiflexion peaked at 27°. Finally, at ipsilateral peak force (IPF; ~84%), loading on the ipsilateral foot peaked at 403 N beneath the metatarsals. Hip and knee reached maximal extension (118° and 114°, respectively), and ankle dorsiflexion was 28°. Discussion The sequential loading patterns identified in plantar pressure distributions support existing models of coordinated limb involvement, particularly highlighting the distinct roles of contralateral and ipsilateral limbs. The contralateral foot's dominance in initial lateral propulsion, followed by the ipsilateral foot's role in trajectory control, emphasizes the complexity of neuromuscular coordination required during dynamic goalkeeper movements. The capability of sensorized insoles to provide detailed pressure distribution data across specific foot regions offers biomechanical insights beyond those obtained through traditional force platforms alone. The observed high plantar pressures in the metatarsal and toe regions highlight the forefoot’s significant role in propulsion. However, the rapid shifts in plantar pressure, combined with ankle dorsiflexion and abduction, may increase stress on ankle structures, potentially predisposing goalkeepers to sprains or chronic instability [3]. Despite these insights, this study presents some inherent limitations. Firstly, it was conducted as a single-case analysis, limiting the generalizability of the results. Moreover, the limited number of trials and the exclusive focus on low dives further restrict the applicability of these findings. These findings highlight the feasibility of wearable sensor technologies for optimizing forefoot loading strategies and ankle stability.
Foot plantar distribution and kinematic analysis of low dive in soccer goalkeepers: a case study
Zinno R.;
2025
Abstract
Introduction The role of goalkeepers in soccer requires rapid, precise movements that combine explosive strength with finely tuned neuromuscular coordination. Although previous studies [1,2] have examined diving techniques using force platforms and optical motion capture, they lack detailed insight into how forces are distributed across different regions of the foot during a dive. To address this gap, we investigated plantar pressure distribution and lower-limb kinematics in an elite female goalkeeper performing low-corner dives, using wearable inertial sensors and sensorized pressure insoles. Methods An 18-year-old goalkeeper from an elite youth team performed four randomized low dives (two per side) intercepting balls launched at approximately 30 cm height and 70 cm from the post. Kinematic data were recorded at 60 Hz with the Xsens MVN Biomech Link system (17 IMUs) and plantar pressures at 100 Hz using XSENSOR® smart insoles. A distinctive foot-strike acceleration peak was used as a synchronization marker across all devices. Time series were normalized from peak hip flexion to ipsilateral foot take-off, and analysis focused on stance width (normalized to leg length), joint angles (hip, knee, ankle), vertical ground reaction forces, and regional plantar pressures at four key instants: preparatory phase, ipsilateral foot initial contact (IFIC), contralateral peak force (CPF), and ipsilateral peak force (IPF). Given the exploratory nature and small sample size, data are presented descriptively without inferential statistics. Results During the preparatory phase (0% of the movement), the total vertical ground reaction force was about 640 N and evenly distributed. Peak pressures occurred under the metatarsals (≈ 136 N) and toes (≈ 126 N). Stance width was 44% of the leg length. Hip flexion measured 105°, knee flexion 59°, and ankle dorsiflexion 17°. At initial foot contact (IFIC; ~48% of the movement phase), contralateral force increased to 341 N. The load shifted toward the midfoot and metatarsals. Stance width increased to 56%. Hip flexion dropped to 93°, and ankle dorsiflexion to 11°.At contralateral peak force (CPF; ~76%), vertical force under the forefoot peaked at 470 N. Stance width reached 84%, and ankle dorsiflexion peaked at 27°. Finally, at ipsilateral peak force (IPF; ~84%), loading on the ipsilateral foot peaked at 403 N beneath the metatarsals. Hip and knee reached maximal extension (118° and 114°, respectively), and ankle dorsiflexion was 28°. Discussion The sequential loading patterns identified in plantar pressure distributions support existing models of coordinated limb involvement, particularly highlighting the distinct roles of contralateral and ipsilateral limbs. The contralateral foot's dominance in initial lateral propulsion, followed by the ipsilateral foot's role in trajectory control, emphasizes the complexity of neuromuscular coordination required during dynamic goalkeeper movements. The capability of sensorized insoles to provide detailed pressure distribution data across specific foot regions offers biomechanical insights beyond those obtained through traditional force platforms alone. The observed high plantar pressures in the metatarsal and toe regions highlight the forefoot’s significant role in propulsion. However, the rapid shifts in plantar pressure, combined with ankle dorsiflexion and abduction, may increase stress on ankle structures, potentially predisposing goalkeepers to sprains or chronic instability [3]. Despite these insights, this study presents some inherent limitations. Firstly, it was conducted as a single-case analysis, limiting the generalizability of the results. Moreover, the limited number of trials and the exclusive focus on low dives further restrict the applicability of these findings. These findings highlight the feasibility of wearable sensor technologies for optimizing forefoot loading strategies and ankle stability.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
