The Influence of Pronated Foot Posture on Knee Isokinetic Strength, Static and Dynamic Postural Stability in Healthy Young Individuals

Abstract

Background: The foot is a complex body structure that plays an important role in static and dynamic situations. Previous studies have reported that altered foot posture might affect knee joint strength and postural stability, however their relationship still remains unclear. Objects:The purpose of this study was to identify whether pronated foot posture has an influence on knee isokinetic strength and static and dynamic postural stability.Methods: Forty healthy young males aged 18 to 26 years were included. Foot posture was evaluated using the Foot Posture Index-6 (FPI-6), and the subjects were divided into two groups according to their FPI-6 scores: a neutral foot group (n = 20, FPI-6 score 0 to +5) and a pronated foot group (n = 20, FPI-6 score +6 or more). Biodex Systems 3 isokinetic dynamometer was used to evaluate knee isokinetic strength and hamstring to quadriceps ratio at three angular velocities: 60°/sec, 90°/sec, and 180°/sec. The static and dynamic postural stability in a single-leg stance under the eyes-open and eyes-closed conditions were measured with a Biodex Balance System.Results: There were no significant differences between the groups in knee isokinetic strength and static postural stability (p > 0.05), but there was a significant difference in the mediallateral stability index (MLSI) for dynamic postural stability under the eyes-closed condition (p = 0.022). The FPI-6 scores correlated significantly only with the dynamic overall stability index (OSI) and the MLSI (OSI: R = 0.344, p = 0.030; MLSI: R = 0.409, p = 0.009) under the eyesclosed condition. Conclusion:Participants with pronated foot had poorer medial-lateral dynamic stability under an eyes-closed condition than those without, and FPI-6 scores were moderately positively correlated with dynamic OSI and dynamic MLSI under the eyes-closed condition. These results suggest that pronated foot posture could induce a change in postural stability, but not in knee isokinetic strength. risk factor for medial tibial stress syndrome and patellofemoral

Correlation of medial longitudinal arch height with postural stability, sensory integration, balance and fall risk among healthy young adults

“…25 overall (r=0.344, p=0.030) and medio-lateral stability index (r= 0.409, p=0.009) under the eyes closed condition only. 11 Menz HB also showed that foot posture, including foot posture index, arch index and navicular height were not significant contributors of poor balance or risk of falls in older people, 26 similar to the findings of the current study in which no significant correlation of Chippaux Smirak Index Score and normalised truncated navicular height was observed with Fall Risk Index. It is also imperative to point out, that there is a dearth of literature in terms of the relationship of medial longitudinal arch height and Chippaux Smirak Index with fall risk and sensory integration of balance.…”

“…10 Moreover, Chun W et al showed no significant differences between pes planus and pes rectus in terms of knee isokinetic strength or static postural stability (p>0.05), but a significant difference was observed in terms of medio-lateral stability index for dynamic postural stability, only under eyes-closed condition (p<0.05). 11 Another study by Hertel J et al has shown a significant difference in terms of postural sway i.e. centre of pressure excursion area, between pes cavus and pes rectus, but no significant differences between pes rectus and pes planus.…”

“…4 From a biomechanical point of view, it is hypothesised that foot posture and medial longitudinal arch height may affect postural stability and balance; however, its impact is not as well established in healthy young adults as compared to other factors such as muscle strength (especially those of the back), proprioception, endurance capacity, and body mass index. 5,6 Moreover, literature seems to be conflicting in terms of comparison of pes planus with pes rectus in terms of balance parameters, with some studies showing significant differences, [7][8][9] whereas others show no significant differences 1,[10][11][12][13] in terms of static and dynamic postural stability, postural control, limits of stability, and other balance measures. Moreover, the studies that do exist have been conducted on very limited sample sizes.…”

The Relationship between Features of Foot Posture, Thickness of Intrinsic Foot Muscles and Dynamic Postural Stability

“…Thus, further study using a variety of methodologies is needed to fully comprehend the changes in balance in individuals with a pronated foot, and to determine the role of different feedback systems in maintaining balance in this population. ous study also demonstrated that pronated foot posture was correlated with attenuated dynamic postural stability under eyes closed condition [3]. It seems individuals who have pronated foot would be more dependent in other sensory system which correlated with balance ability [1].…”

“…The foot, the most distal body structure in contact with relatively small supporting surface, plays a critical role in maintenance of postural stability during human functional movements [1]. As the only body structure in contact directly with the base of support (BOS), it has complex biomechanical structures consisted of various bones, joints, ligaments, extrinsic and intrinsic muscles to adapt to the ground surface [2,3]. These biomechanical complexity leads more interdependence among the foot and ankle joints [4,5], and creates various foot postures; the pronated, supinated, and neutral foot types [6].…”