Acute effect of foot strike patterns on in vivo tibiotalar and subtalar joint kinematics during barefoot running.

BACKGROUND: Foot kinematics, such as excessive eversion and malalignment of the hindfoot, are believed to be associated with running-related injuries. The majority of studies to date show that different foot strike patterns influence these specific foot and ankle kinematics. However, technical deficiencies in traditional motion capture approaches limit knowledge of in vivo joint kinematics with respect to rearfoot and forefoot strike patterns (RFS and FFS, respectively). This study uses a high-speed dual fluoroscopic imaging system (DFIS) to determine the effects of different foot strike patterns on 3D in vivo tibiotalar and subtalar joints kinematics. METHODS: Fifteen healthy male recreational runners underwent foot computed tomography scanning for the construction of 3-dimensional models. A high-speed DFIS (100 Hz) was used to collect 6 degrees of freedom kinematics for participants' tibiotalar and subtalar joints when they adopted RFS and FFS in barefoot condition. RESULTS: Compared with RFS, FFS exhibited greater internal rotation at 0%-20% of the stance phase in the tibiotalar joint. The peak internal rotation angle of the tibiotalar joint under FFS was greater than under RFS (p < 0.001, Cohen's d = 0.92). RFS showed more dorsiflexion at 0%-20% of the stance phase in the tibiotalar joint than FFS. RFS also presented a larger anterior translation (p < 0.001, Cohen's d = 1.28) in the subtalar joint at initial contact than FFS. CONCLUSION: Running with acute barefoot FFS increases the internal rotation of the tibiotalar joint in the early stance. The use of high-speed DFIS to quantify the movement of the tibiotalar and subtalar joint was critical to revealing the effects of RFS and FFS during running.

Effects of Barefoot and Shod Conditions on the Kinematics and Kinetics of the Lower Extremities in Alternating Jump Rope Skipping-A One-Dimensional Statistical Parameter Mapping Study.

PURPOSE: To explore the difference in the biomechanics of the lower extremity during alternating jump rope skipping (AJRS) under barefoot and shod conditions. METHODS: Fourteen experienced AJRS participants were randomly assigned to wear jump rope shoes or be barefoot (BF) during the AJRS at a self-selected speed. The Qualisys motion capture system and Kistler force platform were used to synchronously collect the ground reaction forces and trajectory data of the hip, knee, ankle, and metatarsophalangeal (MTP) joints. One-dimensional statistical parameter mapping was used to analyze the kinematics and kinetics of the lower extremity under both conditions using paired t-tests. RESULTS: Wearing shoes resulted in a significant decrease in the ROM (p < 0.001) and peak angular velocity (p < 0.001) of the MTP joint during the landing phase. In addition, the MTP joint power (p < 0.001) was significantly larger under shod condition at 92-100% of the landing phase. Moreover, wearing shoes reduced the peak loading rate (p = 0.002). CONCLUSION: The findings suggest that wearing shoes during AJRS could provide better propulsion during push-off by increasing the MTP plantarflexion joint power. In addition, our results emphasize the significance of the ankle and MTP joint by controlling the ankle and MTP joint angle.

Effects of different habitual foot strike patterns on in vivo kinematics of the first metatarsophalangeal joint during shod running-a statistical parametric mapping study.

Existing studies on the biomechanical characteristics of the first metatarsophalangeal joint (1st MTPJ) during shod running are limited to sagittal plane assessment and rely on skin marker motion capture, which can be affected by shoes wrapping around the 1st MTPJ and may lead to inaccurate results. This study aims to investigate the in vivo effects of different habitual foot strike patterns (FSP) on the six degrees of freedom (6DOF) values of the 1st MTPJ under shod condition by utilizing a dual-fluoroscopic imaging system (DFIS). Long-distance male runners with habitual forefoot strike (FFS group, n = 15) and rearfoot strike (RFS group, n = 15) patterns were recruited. All participants underwent foot computed tomography (CT) scan to generate 3D models of their foot. The 6DOF kinematics of the 1st MTPJ were collected using a DFIS at 100 Hz when participants performed their habitual FSP under shod conditions. Independent t-tests and one-dimensional statistical parametric mapping (1-d SPM) were employed to analyze the differences between the FFS and RFS groups' 1st MTPJ 6DOF kinematic values during the stance phase. FFS exhibited greater superior translation (3.5-4.9 mm, p = 0.07) during 51%-82% of the stance and higher extension angle (8.4°-10.1°, p = 0.031) during 65%-75% of the stance in the 1st MTPJ than RFS. Meanwhile, FFS exhibited greater maximum superior translation (+3.2 mm, p = 0.022), maximum valgus angle (+6.1°, p = 0.048) and varus-valgus range of motion (ROM) (+6.5°, p = 0.005) in the 1st MTPJ during stance. The greater extension angle of the 1st MTPJ in the late stance suggested that running with FFS may enhance the propulsive effect. However, the higher maximum valgus angle and the ROM of varus-valgus in FFS may potentially lead to the development of hallux valgus.

Changes of the in vivo kinematics of the human medial longitudinal foot arch, first metatarsophalangeal joint, and the length of plantar fascia in different running patterns.

Accurately obtaining the in vivo motion of the medial longitudinal arch (MLA), first metatarsophalangeal joint (MTPJ), and plantar fascia (PF) is essential for analyzing the biomechanics of these structures in different running strike patterns. Most previous studies on the biomechanics of the MLA, first MTPJ, and PF have been based on traditional skin-marker-based motion capture, which cannot acquire the natural foot motion. Therefore, this study aimed to 1) describe the movement of the MLA, first MTPJ, and PF during running by using the high-speed dual fluoroscopic imaging system (DFIS) and 2) explore changes of the in vivo kinematics of the MLA and first MTPJ, and the length of the PF during the stance phase of running with different foot strike patterns. Fifteen healthy male runners all of whom ran with a regular rearfoot strike (RFS) pattern were required to run with forefoot strike (FFS) and RFS patterns. Computed tomography scans were taken from each participant's right foot for the construction of 3D models (the calcaneus, first metatarsal, and first proximal phalanges) and local coordinate systems. A high-speed DFIS (100 Hz) and 3D force platform (2,000 Hz) were used to acquire X-ray images of the foot bones and ground reaction force data during the stance phase of running (3 m/s ± 5%) simultaneously. Then, 3D-2D registration was used to obtain the in vivo kinematic data of the MLA and first MTPJ and the length of the PF. When compared with RFS, in FFS, 1) the range of motion (ROM) of the medial/lateral (5.84 ± 5.61 mm vs. 0.75 ± 3.38 mm, p = 0.002), anterior/posterior (14.64 ± 4.33 mm vs. 11.18 ± 3.56 mm, p = 0.010), plantarflexion/dorsiflexion (7.13 ± 3.22° vs. 1.63 ± 3.29°, p < 0.001), and adduction/abduction (-3.89 ± 3.85° vs. -0.64 ± 4.39°, p = 0.034) motions of the MLA were increased significantly; 2) the ROM of the anterior/posterior (7.81 ± 2.84 mm vs. 6.24 ± 3.43 mm, p = 0.003), superior/inferior (2.11 ± 2.06 mm vs. -0.57 ± 1.65 mm, p = 0.001), and extension/flexion (-9.68 ± 9.16° vs. -5.72 ± 7.33°, p = 0.018) motions of the first MTPJ were increased significantly; 3) the maximum strain (0.093 ± 0.023 vs. 0.075 ± 0.020, p < 0.001) and the maximum power (4.36 ± 1.51 W/kg vs. 3.06 ± 1.39 W/kg, p < 0.001) of the PF were increased significantly. Running with FFS may increase deformation, energy storage, and release of the MLA and PF, as well as the push-off effect of the MTPJ. Meanwhile, the maximum extension angle of the first MTPJ and MLA deformation increased in FFS, which showed that the PF experienced more stretch and potentially indicated that FFS enhanced the PF mechanical responses.

Effects of intervention combining transcranial direct current stimulation and foot core exercise on sensorimotor function in foot and static balance.

OBJECTIVE: This study aimed to examine the effects of combining transcranial direct current stimulation (tDCS) and foot core exercise (FCE) on the sensorimotor function of the foot (i.e., toe flexor strength and passive ankle kinesthesia) and static balance. METHODS: In this double-blinded and randomized study, 30 participants were randomly assigned into two groups: tDCS combined with FCE and sham combined with FCE (i.e., control group). The participants received 2 mA stimulation for 20 min concurrently with FCE over 4 weeks (i.e., three sessions per week). After the first two groups completed the intervention, a reference group (FCE-only group) was included to further explore the placebo effects of sham by comparing it with the control group. Foot muscle strength, passive ankle kinesthesia, and static balance were assessed at baseline and after the intervention. RESULTS: Compared with the control group and baseline, tDCS combined with FCE could increase toe flexor strength (p < 0.001) and decrease the passive kinesthesia threshold of ankle eversion (p = 0.002). No significant differences in static balance were observed between tDCS + FCE and control groups. The linear regression models showed an association towards significance between the percent changes in metatarsophalangeal joint flexor strength and the anteroposterior average sway velocity of the center of gravity in one-leg standing with eyes closed following tDCS + FCE (r2 = 0.286; p = 0.057). The exploratory analysis also showed that compared with FCE alone, the sham stimulation did not induce any placebo effects during FCE. CONCLUSION: Participating in 4 weeks of intervention using tDCS in combination with FCE effectively enhances toe flexor strength and foot-ankle sensory function.

Effects of Barefoot and Shod on the In Vivo Kinematics of Medial Longitudinal Arch During Running Based on a High-Speed Dual Fluoroscopic Imaging System.

Shoes affect the biomechanical properties of the medial longitudinal arch (MLA) and further influence the foot's overall function. Most previous studies on the MLA were based on traditional skin-marker motion capture, and the observation of real foot motion inside the shoes is difficult. Thus, the effect of shoe parameters on the natural MLA movement during running remains in question. Therefore, this study aimed to investigate the differences in the MLA's kinematics between shod and barefoot running by using a high-speed dual fluoroscopic imaging system (DFIS). Fifteen healthy habitual rearfoot runners were recruited. All participants ran at a speed of 3 m/s ± 5% along with an elevated runway in barefoot and shod conditions. High-speed DFIS was used to acquire the radiographic images of MLA movements in the whole stance phase, and the kinematics of the MLA were calculated. Paired sample t-tests were used to compare the kinematic characteristics of the MLA during the stance phase between shod and barefoot conditions. Compared with barefoot, shoe-wearing showed significant changes (p < 0.05) as follows: 1) the first metatarsal moved with less lateral direction at 80%, less anterior translation at 20%, and less superiority at 10-70% of the stance phase; 2) the first metatarsal moved with less inversion amounting to 20-60%, less dorsiflexion at 0-10% of the stance phase; 3) the inversion/eversion range of motion (ROM) of the first metatarsal relative to calcaneus was reduced; 4) the MLA angles at 0-70% of the stance phase were reduced; 5) the maximum MLA angle and MLA angle ROM were reduced in the shod condition. Based on high-speed DFIS, the above results indicated that shoe-wearing limited the movement of MLA, especially reducing the MLA angles, suggesting that shoes restricted the compression and recoil of the MLA, which further affected the spring-like function of the MLA.

Influence of Shod and Barefoot Running on the In Vivo Kinematics of the First Metatarsophalangeal Joint.

The biomechanics of the first metatarsophalangeal joint (MTPJ) is affected by different shoe conditions. In the biomechanical research field, traditional skin marker motion capture cannot easily acquire the in vivo joint kinematics of the first MTPJ in shoes. Thus, the present study aims to investigate the differences of the first MTPJ's six-degree-of-freedom (6DOF) kinematics between shod and barefoot running by using a high-speed dual fluoroscopic imaging system (DFIS). In total, 15 healthy male runners were recruited. Computed tomography scans were taken from each participant's right foot for the construction of 3D models and local coordinate systems. Radiographic images were acquired at 100 Hz while the participants ran at a speed of 3 m/s ± 5% in shod and barefoot conditions along an elevated runway, and 6DOF kinematics of the first MTPJ were calculated by 3D-2D registration. Paired sample t-tests were used to compare the kinematic characteristics of the first MTPJ 6DOF kinematics during the stance phase between shod and barefoot conditions. Compared with barefoot, wearing shoes showed significant changes (p < 0.05): 1) the first MTPJ moved less inferior at 50% but moved less superior at 90 and 100% of the stance phase; 2) the peak medial, posterior, and superior translation of the first MTPJ significantly decreased in the shod condition; 3) the extension angle of the first MTPJ was larger at 30-60% but smaller at 90 and 100% of the stance phase; 4) the maximum extension angle and flexion/extension range of motion of the first MTPJ were reduced; and 5) the minimum extension and adduction angle of the first MTPJ was increased in the shod condition. On the basis of the high-speed DFIS, the aforementioned results indicated that wearing shoes limited the first MTPJ flexion and extension movement and increased the adduction angle, suggesting that shoes may affect the propulsion of the first MTPJ and increase the risk of hallux valgus.

In Vivo Foot and Ankle Kinematics During Activities Measured by Using a Dual Fluoroscopic Imaging System: A Narrative Review.

Foot and ankle joints are complicated anatomical structures that combine the tibiotalar and subtalar joints. They play an extremely important role in walking, running, jumping and other dynamic activities of the human body. The in vivo kinematic analysis of the foot and ankle helps deeply understand the movement characteristics of these structures, as well as identify abnormal joint movements and treat related diseases. However, the technical deficiencies of traditional medical imaging methods limit studies on in vivo foot and ankle biomechanics. During the last decade, the dual fluoroscopic imaging system (DFIS) has enabled the accurate and noninvasive measurements of the dynamic and static activities in the joints of the body. Thus, this method can be utilised to quantify the movement in the single bones of the foot and ankle and analyse different morphological joints and complex bone positions and movement patterns within these organs. Moreover, it has been widely used in the field of image diagnosis and clinical biomechanics evaluation. The integration of existing single DFIS studies has great methodological reference value for future research on the foot and ankle. Therefore, this review evaluated existing studies that applied DFIS to measure the in vivo kinematics of the foot and ankle during various activities in healthy and pathologic populations. The difference between DFIS and traditional biomechanical measurement methods was shown. The advantages and shortcomings of DFIS in practical application were further elucidated, and effective theoretical support and constructive research direction for future studies on the human foot and ankle were provided.

[Progress on in vivo ankle biomechanics based on dual fluoroscopic imaging technology].

The technical deficiencies in traditional medical imagining methods limit the study of in vivo ankle biomechanics. A dual fluoroscopic imaging system (DFIS) provides accurate and non-invasive measurements of dynamic and static activities in joints of the body. This approach can be used to quantify the movement in the single bones of the ankle and analyse different morphological and complex bone positions and movement patterns within these organs and has been widely used in the field of image diagnosis and evaluation of clinical biomechanics. This paper reviews the applications of DFIS that were used to measure the in vivo kinematics of the ankle in the field of clinical and sports medicine. The advantages and shortcomings of DFIS in the practical application are summarised. We further put forward effective research programs for understanding the movement as well as injury mechanism of the ankle in vivo, and provide constructive research direction for future study.

Alterations in Running Biomechanics after 12 Week Gait Retraining with Minimalist Shoes.

Purpose: The intervention of 12 week gait retraining with minimalist shoes was established to examine its effect on impact forces, joint mechanics, and vertical stiffness during running. Methods: Thirty male recreational runners were randomly assigned to the gait retraining + minimalist shoe (n = 15, GR) and minimalist shoe (n = 15, MIN) groups. The ground reaction force and marker trajectories were collected before and after intervention at a speed of 3.33 ± 5% m/s. Results: A total of 17 participants (9 in the GR group and 8 in the MIN group) completed the training. After training, (1) the loading rate of both groups decreased significantly, and the loading rate of the GR group was lower than that of the MIN group. (2) The foot strike angle of the GR group decreased significantly after training, and the plantarflexion angle and hip joint angular extension velocity increased in both groups. (3) The moment of ankle joint increased in the GR group, and the stiffness of lower limbs was significantly improved in both groups. Conclusion: The 12 week gait retraining with minimalist shoes converted rearfoot strikers into forefoot strikers with a rate of 78% (7/9). More importantly, such a combined program, compared to the training with only minimalist shoes, can avoid the peak impact force and decrease the loading rate more effectively, thus providing a potential means of reducing risk of running injury caused by impact forces. Moreover, the increased vertical stiffness of lower extremity after gait retraining may improve running economy and corresponding energy utilization. However, these observations also suggest that the sole use of minimalist footwear may have limited effects on reducing running-related impacts.