The influence of altered lower-limb muscle strength on dynamic plantar pressure distribution in participants who underwent anterior cruciate ligament reconstruction

Karolína Matov¹Michal Bozděch²Marta Gimunová¹Martin Komzák¹Marek Dostál³Miloslav Maršálek⁴Tomáš Vespalec¹Milan Mojžíš¹Tomáš Vodička^1*

• ¹Faculty of Sports Studies, Department of Physical Activities and Health Sciences, Masaryk University, Brno, Czechia
• ²Department of Physical Education and Social Sciences – Faculty of Sports Studies, Brno, Czechia
• ³Department of Biophysics – Theoretical Departments – Faculty of Medicine, Brno, Czechia
• ⁴Office for Specialised Education of Doctors and Non-Medical Health Professionals – Dean's Office – Administration Office – Faculty of Medicine, Brno, Czechia

Deficits in lower-limb muscle strength and altered gait mechanics are common after anterior cruciate ligament reconstruction (ACL). While isokinetic strength testing is widely accepted in return-to-sport assessment, the role of plantar pressure analysis in detecting compensatory gait strategies remains underexplored. This study included 10 male patients (30.27 ± 5.59 years; 178.37 ± 6.30 cm; 84.85 ± 10.74 kg) who underwent ACL reconstruction using bone-patellar tendon-bone autografts. Assessments were performed preoperatively and at 3 and 6 months postoperatively, evaluating isokinetic knee strength and plantar pressure distribution during barefoot level walking. Non-parametric Friedman tests with Kendall's W assessed temporal differences, followed by Conover post hoc tests with Bonferroni correction. Spearman's rank correlation examined associations between muscle strength and plantar pressure.Significant deficits in extensor strength were found at both postoperative time points compared to preoperative levels (both p < .001), with improvement at six months vs. three (p < .001). Flexor strength showed a similar but less pronounced recovery (p = .005). Plantar pressure analysis revealed changes relative to baseline: reduced hindfoot contact area at six months (p = .035), decreased midfoot maximum force at three (p = .047) and six months (p = .026), and lower peak pressure under the fifth metatarsal head at six months (p = .035). No significant correlations emerged between muscle strength and plantar pressure parameters.These findings suggest plantar pressure analysis may complement return-to-sport evaluation by revealing hindfoot asymmetries persisting despite strength recovery. However, as dynamic plantar pressure parameters do not reflect quadriceps or hamstring status reliably, they cannot replace standard tests like isokinetic dynamometry. Combining plantar pressure metrics with conventional strength and functional assessments may better identify residual gait deficits and guide targeted rehabilitation to lower reinjury risk.