scholarly journals Effect of a task’s postural demands on medial longitudinal arch deformation and activation of foot intrinsic and extrinsic musculatur

2020 ◽  
Vol 22 (4) ◽  
Author(s):  
Toshiyuki Kurihara ◽  
Michael_ Rowley ◽  
Stephen Reischl ◽  
Lucinda Baker ◽  
Kornelia Kulig

Purpose: It is not well established how motion and muscle activation of the medial longitudinal arch (MLA) of the foot vary under different loading conditions. Intrinsic and extrinsic foot muscles may play a role in postural control, which may be investigated by comparing loading tasks with differing postural demands. The objective of this study was to investigate the interaction of MLA flexibility and loading task on muscle activation. Methods: Twenty healthy adults completed two instrumented single-foot loading tasks: controlled external load of 50% body weight while sitting and bilateral standing. Fine-wire intramuscular and surface electromyography collected flexor hallucis brevis, abductor hallucis, tibialis posterior, flexor hallucis longus, tibialis anterior, and peroneus longus activation. MLA deformation was measured as a percent change in navicular height with loading. Results: During seated external loading, greater MLA deformation was associated with greater muscle activation for all instrumented muscles (R2 = 0.224–0.303, p < 0.05) except for tibialis anterior. During bilateral stance, there were no correlations between MLA deformation and muscle activation. Activation of all extrinsic muscles except for tibialis anterior were greater during bilateral standing than during external loading (p = 0.002–0.013), indicating activation of these muscles was caused by postural demands of the standing task, not simply load. Conclusions: MLA deformation and muscle activation are strongly task-dependent.

2020 ◽  
pp. 1-7
Author(s):  
Jung-Hoon Choi ◽  
Heon-Seock Cynn ◽  
Chung-Hwi Yi ◽  
Tae-Lim Yoon ◽  
Seung-Min Baik

Context: The improvement of hip joint stability can significantly impact knee and rearfoot mechanics. Individuals with pes planus have a weak abductor hallucis (AbdH), and the tibialis anterior (TA) may activate to compensate for this. As yet, no studies have applied isometric hip abduction (IHA) for hip stability during short-foot exercise (SFE). Objective: To compare the effects of IHA on the muscle activity of the AbdH, TA, peroneus longus (PL), and gluteus medius (Gmed), as well as the medial longitudinal arch (MLA) angle during sitting and standing SFE. Design: Two-way repeated analyses of variance were used to determine the statistical significance of AbdH, TA, PL, and Gmed electromyography activity, as well as the change in MLA angle. Setting: University research laboratory. Participants: Thirty-two participants with pes planus. Intervention(s): The participants performed SFE with and without isometric hip abduction in sitting and standing positions. Main Outcome Measures: Surface electromyography was used to measure the activity of the AbdH, TA, PL, and Gmed muscles, and Image J was used to measure the MLA angle. Results: Significant interactions between exercise type and position were observed in terms of the PL muscle activity and in the change in MLA angle only, while other muscles showed significant main effects. The IHA during SFE significantly increased the AbdH muscle activity, while the TA muscle activity was significantly lower. The muscle activity of Gmed and PL was significantly increased in the standing position compared with sitting, but there was no significant difference with or without IHA. The change in the MLA angle was significantly greater in SFE with IHA in a standing position than in the other SFE conditions. Conclusions: IHA may be an effective method for reducing compensatory TA activity and increasing AbdH muscle activity during SFE for individuals with pes planus.


Author(s):  
Sharon Dixon ◽  
Sophie Roberts

An orthotic is a custom-made insole which fits inside a shoe with the purpose of changing the way in which the foot functions during both standing and dynamic gait. There are many theories regarding the influence of these devices on the foot and lower limb. It is widely accepted that the fundamental principle is that an orthotic encourages a change in the movement pattern of the foot, aiming to alleviate stress to musculoskeletal structures, and produce changes in muscle firing patterns. An example of how an orthotic works is when one is used to change the functioning position of the medial longitudinal arch of the foot by altering the orientation of the calcaneus and potentially reducing the demand on the tibialis posterior tendon....


2020 ◽  
Vol 28 (4) ◽  
pp. 415-422
Author(s):  
Min-Hyeok Kang ◽  
Sang-Min Cha ◽  
Jae-Seop Oh

BACKGROUND: Active interventions for pes planus, including short-foot exercises (SF) and toe-spread-out exercises (TSO), aim to continuously support the medial longitudinal arch (MLA) by activating the abductor hallucis (AbdH) muscle. However, compensatory movements, such as ankle supination and/or plantar flexion, often occur during these exercises. OBJECTIVE: To examine the effects of a novel exercise, i.e., the toe-tap (TT) exercise on AbdH activity and MLA angle. METHODS: A total of 16 participants with pes planus participated in this study. Participants performed SF, TSO, and TT exercises. Electromyographic activity of the AbdH and MLA angle during three AbdH contraction exercises were recorded using surface EMG system and digital image analysis program, respectively. The differences in outcome measures among the three exercises were analyzed using one-way repeated-measures analysis of variance. RESULTS: The EMG activity of the AbdH was significantly greater during the TT exercise compared to the SF and TSO exercises. The MLA angle was significantly smaller during the TT exercise compared with the SF and TSO exercises. CONCLUSIONS: These findings suggest that the TT exercise could be effective in activating the AbdH and increasing height of the MLA, as part of a sports rehabilitation program for individuals with pes planus.


2018 ◽  
Vol 40 (3) ◽  
pp. 352-355 ◽  
Author(s):  
Eric Swanton ◽  
Lauren Fisher ◽  
Andrew Fisher ◽  
Andrew Molloy ◽  
Lyndon Mason

Background: Weight-bearing radiographic analysis of pes planus deformities show, with varying degree of severity, a break in the Meary line. The break in the Meary line occurs not only at the talonavicular joint but also distal to the spring ligament and reported tibialis posterior insertion. Our aim in this study was to investigate the distal plantar ligaments of the medial longitudinal arch, to try to identify other areas where deformity correction could be affected. Methods: We examined 11 cadaveric lower limbs that had been preserved for dissection in a solution of formaldehyde. The lower limbs were carefully dissected to identify the plantar aspect of the medial longitudinal arch. Results: In all specimens, the tibialis posterior tendon inserted into the plantar medial aspect of the navicular with separate slips to the intermediate and lateral cuneiform. The navicular cuneiform ligament extended from the navicular to medial cuneiform. This structure was statically inserted between the navicular and medial cuneiform, which would allow the pull of the tibialis posterior to act on the navicular and medial cuneiform in tandem. The average width of the naviculocuneiform ligament was 15.2 mm (range 12.4-18.0) compared to 9.5 mm (range 7.6-11.4) for the tibialis posterior tendon. Conclusion: The tibialis posterior tendon inserted into the navicular and continued onto the medial cuneiform to provide a static restraint between 2 bony insertions, thus supporting the distal aspect of the medial longitudinal arch. Clinical Relevance: We are confident that it is a structure of importance in maintaining the distal aspect of the medial longitudinal arch and may therefore have significant clinical and surgical implications when treating the pes planus deformity.


2021 ◽  
Vol 30 (1) ◽  
pp. 120-128
Author(s):  
Jinah Kim ◽  
Sung Cheol Lee ◽  
Youngmin Chun ◽  
Hyung-Pil Jun ◽  
Jeffrey G. Seegmiller ◽  
...  

Context: Clinically, it has been suggested that increased activation of intrinsic foot muscles may alter the demand of extrinsic muscle activity surrounding the ankle joint in patients with stage II posterior tibial tendon dysfunction. However, there is limited empirical evidence supporting this notion. Objective: The purpose of this study was to investigate the effects of a 4-week short-foot exercise (SFE) on biomechanical factors in patients with stage II posterior tibial tendon dysfunction. Design: Single-group pretest–posttest. Setting: University laboratory. Participants: Fifteen subjects (8 males and 7 females) with stage II posterior tibial tendon dysfunction who had pain in posterior tibial tendon, pronated foot deformity (foot posture index ≥+6), and flexible foot deformity (navicular drop ≥10 mm) were voluntarily recruited. Intervention: All subjects completed a 4-week SFE program (15 repetitions × 5 sets/d and 3 d/wk) of 4 stages (standing with feedback, sitting, double-leg, and one-leg standing position). Main Outcome Measures: Ankle joint kinematics and kinetics and tibialis anterior and fibularis longus muscle activation (% maximum voluntary isometric contraction) during gait were measured before and after SFE program. Cohen d effect size (ES [95% confidence intervals]) was calculated. Results: During the first rocker, tibialis anterior activation decreased at peak plantarflexion (ES = 0.75 [0.01 to 1.49]) and inversion (ES = 0.77 [0.03 to 1.51]) angle. During the second rocker, peak dorsiflexion angle (ES = 0.77 [0.03 to 1.51]) and tibialis anterior activation at peak eversion (ES = 1.57 [0.76 to 2.39]) reduced. During the third rocker, the peak abduction angle (ES = 0.80 [0.06 to 1.54]) and tibialis anterior and fibularis longus activation at peak plantarflexion (ES = 1.34 [0.54 to 2.13]; ES = 1.99 [1.11 to 2.86]) and abduction (ES = 1.29 [0.50 to 2.08]; ES = 1.67 [0.84 to 2.50]) decreased. Conclusions: Our 4-week SFE program may have positive effects on changing muscle activation patterns for tibialis anterior and fibularis longus muscles, although it could not influence their structural deformity and ankle joint moment. It could produce a potential benefit of decreased tibialis posterior activation.


Healthcare ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 44
Author(s):  
Youngkyu Choi ◽  
Jihyun Lee

Pes planus is a medical condition of the foot wherein there is a flattening or lowering of the medial longitudinal arch. The abductor hallucis muscle starts at the heel bone and attaches to the medial side of the first toe. Whenever it contracts, it plays a key role in elevating the medial longitudinal arch. Hence, the abductor hallucis muscle should be strong enough to control the depression on the medial longitudinal arch. The peroneus longus muscle plantarflexes the ankle and everts the ankle and subtalar joint. If this muscle contracts more than the abductor hallucis muscle does, the medial longitudinal arch of the foot is depressed. This study aimed to investigate the effect of myofascial release of the peroneus longus before performing the toe-tap exercise for strengthening the abductor hallucis muscle in participants with flexible pes planus. This cross-over study included 16 volunteers with flexible pes planus. The participants performed a toe-tap exercise before and after the myofascial release of the peroneus longus. During the toe-tap exercise, the muscle activity of the abductor hallucis and peroneus longus were measured using a Delsys Trigno Wireless Electromyography System. The angle of the medial longitudinal arch was measured using Image J software. Photos in the sagittal plane were used. The peroneus longus activity and medial longitudinal arch angles were significantly decreased. On the other hand, the activity of the abductor hallucis significantly increased after the myofascial release of the peroneus longus before performing the toe-tap exercise (p < 0.05). Individuals with flexible pes planus should be encouraged to perform myofascial release of the peroneus longus before the toe-tap exercise to improve the abductor hallucis activity and to elevate the medial longitudinal arch.


2011 ◽  
Vol 12 (1) ◽  
pp. 30-35 ◽  
Author(s):  
Do-Young Jung ◽  
Moon-Hwan Kim ◽  
Eun-Kyung Koh ◽  
Oh-Yun Kwon ◽  
Heon-Seock Cynn ◽  
...  

2016 ◽  
Vol 96 (8) ◽  
pp. 1216-1224 ◽  
Author(s):  
Jasper W.K. Tong ◽  
Pui W. Kong

Abstract Background It is unclear at what age the medial longitudinal arch (MLA) of the foot becomes stable in children. The influence of footwear on MLA development also is unknown. Objective The purpose of this study was to examine the MLA development of children using a longitudinal approach. The relationship between wearing different types of footwear and MLA development also was explored longitudinally. Design This was a longitudinal cohort observational study. Methods The MLA of 111 healthy children (mean age=6.9 years, SD=0.3) was evaluated using 3 parameters (arch index [AI], midfoot peak pressure [PP], and maximum force [MF]) extracted from dynamic foot loading measurements at baseline (t0), 10-month follow-up (t1), and 22-month follow-up (t2). Information on footwear usage was surveyed. Linear mixed modeling was used to test for differences in MLA over time. Results The MLA of the children remained stable over time (AI: t0/t1/t2=0.25 [95% confidence interval (CI)=0.24, 0.26]/0.25 [95% CI=0.24, 0.26]/0.25 [95% CI=0.24, 0.26]; P=.95). When the children's sex was considered, the AI of boys decreased (higher arch) with age (0.26 [95% CI=0.24, 0.27]/0.25 [95% CI=0.24, 0.27]/0.25 [95% CI=0.23, 0.27]; P=.02). Boys also displayed a flatter MLA than girls at age 6.9 years (AI: mean difference=0.02 [95% CI=0.01, 0.04]; P=.02). At baseline, children who wore closed-toe shoes displayed the lowest MLA overall (AI: closed-toe shoes/sandals/slippers=0.26 [95% CI=0.24, 0.28]/0.24 [95% CI=0.23, 0.25]/0.25 [95% CI=0.24, 0.26]; P&lt;.01). Children who used slippers at toddlers' age experienced a higher PP (flatter arch) in later childhood than those who wore sandals (mean difference=31.60 kPa [95% CI=1.44, 61.75]; post hoc P=.04). Limitations Information on the type of footwear worn was self-reported and, therefore, may be subjected to recall bias. Conclusions The MLA of children remained stable from 7 to 9 years of age. The child's sex and the type of footwear worn during childhood may influence MLA development.


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