Does the pregnancy-related adaptation of gait biomechanics after childbirth recover to its pre-pregnancy state?: A systematic review.

BACKGROUND: Although changes in the gait biomechanics during pregnancy are known to occur, it is unclear whether they return to their original state after childbirth. RESEARCH QUESTION: The objective of the current systematic review is to summarize existing literature reporting the biomechanical characteristics of gait in postpartum women and to identify knowledge gaps that calls for future investigations in this population. METHODS: Relevant articles were selected using MEDLINE (PubMed), Scopus (Elsevier), Embase (Elsevier), and Web of Science (Clarivate Analytics). Articles were included if they met the following criteria: They must (1) include postpartum women, (2) report measures related to three-dimensional (3D) kinematics and/or kinetics, (3) have been published after 1990, and (4) have been published in English. RESULTS AND SIGNIFICANCE: The current systematic review included a total of 14 articles, five of which compare the data from postpartum women with nulliparous women or pre-pregnancy data. We observed that gait biomechanics changes of postpartum women could persist for more than 5 years after the childbirth. This review provides novel viewpoints on the biomechanics of postpartum women's gait and recommendations for future studies to fully understand these changes and improve postpartum women's physical and mental wellbeing.

Damage and recovery of the intrinsic and extrinsic foot muscles from running a full marathon.

PURPOSE: To investigate the effects of full marathon running on intrinsic and extrinsic foot muscle damage and to determine the relationship with the height change of the longitudinal foot arch following full marathon completion. METHODS: Magnetic resonance imaging-measured transverse relaxation time (T2 ) of the abductor hallucis (ABH), flexor digitorum brevis (FDB) and quadratus plantae (QP), flexor digitorum longus (FDL), tibialis posterior (TP), and flexor hallucis longus (FHL) from 22 collegiate runners were assessed before and 1, 3, and 8 days after full marathon running. The three-dimensional foot posture of 10 of the 22 runners was further obtained using a foot scanner system before and 1, 3, and 8 days after the marathon. RESULTS: Marathon-induced increases in T2 were observed in the QP, FDL, TP, and FHL 1 day after the marathon (+7.5%, +4.7%, +6.7%, and +5.9%, respectively), with the increased T2 of TP persisting until 3 days after the marathon (+4.6%). T2 changes of FDL and FHL from pre-marathon to DAY 1 showed direct correlations with the corresponding change in the arch height ratio (r = 0.823, p = 0.003, and r = 0.658, p = 0.038). CONCLUSION: The damage and recovery response from a full marathon differed among muscles; QP, FDL, TP, and FHL increased T2 after the marathon, whereas ABH and FDB did not. In addition, T2 changes in FDL and FHL and the arch height ratio change were correlated. Our results suggest that the extrinsic foot muscles could be more susceptible to damage than the intrinsic during marathon running.

Less impact absorption at the ankle joint is related to the single-leg landing stability deficit in patients with chronic ankle instability.

Single-leg landing (SLL) stability deficits are common dysfunctions after lateral ankle sprain (LAS), and are associated with reinjury and needs to be addressed. SLL stability deficits could be associated with impact absorption ability. Thus, we evaluated these relationships. We recruited 46 patients with chronic ankle instability (CAI) and 64 control patients and measured their kinematics, SLL stability, and impact absorption ability. The SLL stability was evaluated by calculating the anterior-posterior stability index (APSI) and medial-lateral stability index (MLSI). The impact absorption ability was evaluated by calculating the energy absorption (EA). The large negative value of the EA indicated the absorption of a large amount of energy. The Japanese version of identification of functional ankle instability (IdFAI-J) score (P < 0.001), MLSI value (P = 0.004), and sagittal plane ankle EA value (less EA at ankle joint) (P < 0.001) were significantly high in CAI, and sagittal plane knee EA value (more EA at knee joint) (P < 0.041) was significantly low in CAI than in the control group. Multiple regression analysis showed that the APSI was associated with sagittal plane ankle EA (ß = 0.275, P = 0.004). The MLSI was associated with sagittal plane ankle EA (ß = 0.204, P = 0.034) and the idFAI score (ß = 0.234, P = 0.015). The SLL stability impairment after LAS was related to decreased impact absorption ability at the ankle joint.

Progressive Changes in Lumbopelvic Alignment during the Three Month-Postpartum Recovery Period.

Pregnancy-related lumbopelvic pain is a common musculoskeletal problem, and postural changes are believed to be involved in these disorders. However, the lumbopelvic alignment changes in postpartum women remain unclear. This study aimed to determine whether there are changes in lumbopelvic alignment following vaginal or cesarean delivery and when these alignment changes occur after delivery. Thirty postpartum females (PP group) and 20 nulliparous female controls (CTL group) underwent anteroposterior, lateral pelvic, and lower-back X-ray in a static upright position. Digital radiographic images were analyzed and three radiographic variables, the pelvic incidence, pubic symphysis width, and sacral slope, were measured. The pubic symphysis width of the PP group was significantly larger immediately and one month after childbirth (PP group: 6.0 ± 1.1 mm (immediately), 5.0 ± 1.2 mm (one month); CTL group: 3.4 ± 0.4 mm; F = 31.79, p < 0.001). The sacrum slope in the PP group was significantly larger than in the CTL group 1 month after childbirth (PP group: 39.9 ± 6.6°; CTL group: 32.8 ± 5.1°; F = 2.59, p = 0.05). A two-way analysis of variance indicated no statistically significant main effects or interaction effects between the delivery modes on the pubic symphysis width or the sacrum slope. This study suggested that the course of lumbopelvic alignment progressed towards recovery for at least one month, and that these changes were independent of the delivery method.

Increase in foot arch asymmetry after full marathon completion.

Long-distance running results in lowering of the foot medial longitudinal arch, but it is unknown whether the left and right arches decrease equally. This study aimed to determine whether foot arch asymmetry increases upon completion of a full marathon and to identify factors capable of explaining the degree of asymmetry of navicular height and navicular height displacement. The three-dimensional foot posture data of 74 collegiate runners were obtained using an optical foot scanner system before (PRE) and immediately after (POST) a full marathon. The navicular height and arch height ratio (normalised navicular height by foot length) of both feet significantly decreased from PRE to POST full marathon completion (44.3 ± 6.3 mm versus 40.8 ± 6.5 mm, 17.8 ± 2.5 versus 16.6 ± 2.7, respectively; p < 0.001, both). The asymmetry of the arch height ratio was significantly greater POST than PRE marathon. Multiple linear regression analysis indicated that the POST-race Asymmetry Index (AI) of navicular height was significantly predicted by the PRE-race AI of navicular height; navicular height displacement was predicted by PRE-race navicular height and the marathon time. Full marathon running induced increasing asymmetry and lowering of the medial longitudinal arch in runners.

Recovery of Abdominal Muscle Thickness and Contractile Function in Women after Childbirth.

Abdominal muscles may be both morphologically and functionally affected by pregnancy. Dysfunction of the muscles can lead to persistent postpartum low back pain. The recovery process of the abdominal muscles following childbirth is not well understood. This study aimed to demonstrate the changes in the thickness and contractile function of abdominal muscles during the first six months postpartum. Nine perinatal and 15 nulliparous females participated. The thicknesses and contraction/relaxation thickness ratios of the rectus abdominis (RA), external abdominal oblique (EO), internal abdominal oblique (IO), and transverse abdominis (TrA) were measured using ultrasound images from 36-39 weeks' gestation until six months postpartum. The RA, IO, and TrA muscles were thinner in perinatal females than controls at 36-39 weeks of gestation (4.8 vs. 9.47 mm (RA), 5.45 vs. 7.73 mm (IO), 2.56 vs. 3.38 mm (TrA), respectively). The thinner IO muscle persisted for six months after delivery. The decreased TrA thickness ratio persisted until four months post-delivery. Abdominal muscle thickness and contractile function decreased in the postpartum period. Therefore, abdominal muscle exercises might help prevent postpartum symptoms; however, because deterioration of muscle function is significant in the first four months, careful attention should be paid to exercise intensity. The study limitation was a relatively small sample size, thus future studies should involve more participants.

Regional differences in hamstring muscle damage after a marathon.

Previous studies suggest that marathon running induces lower extremity muscle damage. This study aimed to examine inter- and intramuscular differences in hamstring muscle damage after a marathon using transverse relaxation time (T2)-weighted magnetic resonance images (MRI). 20 healthy collegiate marathon runners (15 males) were recruited for this study. T2-MRI was performed before (PRE) and at 1 (D1), 3 (D3), and 8 days (D8) after marathon, and the T2 values of each hamstring muscle at the distal, middle, and proximal sites were calculated. Results indicated that no significant intermuscular differences in T2 changes were observed and that, regardless of muscle, the T2 values of the distal and middle sites increased significantly at D1 and D3 and recovered at D8, although those values of the proximal site remained constant. T2 significantly increased at distal and middle sites of the biceps femoris long head on D1 (p = 0.030 and p = 0.004, respectively) and D3 (p = 0.007 and p = 0.041, respectively), distal biceps femoris short head on D1 (p = 0.036), distal semitendinosus on D1 (p = 0.047) and D3 (p = 0.010), middle semitendinosus on D1 (p = 0.005), and distal and middle sites of the semimembranosus on D1 (p = 0.008 and p = 0.040, respectively) and D3 (p = 0.002 and p = 0.018, respectively). These results suggest that the distal and middle sites of the hamstring muscles are more susceptible to damage induced by running a full marathon. Conditioning that focuses on the distal and middle sites of the hamstring muscles may be more useful in improving recovery strategies after prolonged running.

In vivo talocrural and subtalar kinematics during the stance phase of walking in individuals with repetitive ankle sprains.

Ankle sprains may lead to chronic ankle instability and can progress to ankle osteoarthritis due to the abnormal kinematics after an ankle sprain. However, the characteristics of talocrural and subtalar joint kinematics in individuals with repetitive ankle sprains during locomotion is unclear. The purpose of this study was to quantify the differences of talocrural and subtalar joint kinematics between individuals with and without history of ankle sprains during the walking stance phase. Lateral fluoroscopic images from 10 participants with history of repetitive ankle sprains (AS group) and 8 healthy volunteers (Control group) were obtained between the time of heel contact and toe-off, and the three-dimensional bone orientations were determined using 3D-2D model-image registration techniques to compare the kinematic differences between the two groups. The AS group exhibited a greater talocrural internal rotation from heel contact to 60% of the stance phase than the control group. The results of this study indicate that ankles with repetitive sprains have different talocrural kinematics, and that greater talocrural internal rotation may become a factor in the development of ankle osteoarthritis.

Fear Avoidance Beliefs in College Athletes with a History of Ankle Sprain.

Ankle sprains are the most prevalent injuries, and elevated fear avoidance beliefs after ankle sprain episodes could inhibit athletic performance and contribute to residual symptoms, such as functional and/or mechanical instability. However, it remains unclear how fear avoidance beliefs differ according to conditions of posttraumatic sequelae. The purpose of this study was to determine whether fear of movement/reinjury differed between individuals with and without functional ankle instability (FI, NFI) and healthy controls (CON) and to examine the relationship between fear and ankle joint laxity by sex. Participants (115 male athletes, 105 female athletes) completed the Identification of Functional Ankle Instability, Athlete Fear Avoidance Questionnaire (AFAQ), Tampa Scale for Kinesiophobia (TSK), and ankle joint laxity test. Total 168 athletes (79 males, 89 females) data were eligible for analysis. The results demonstrated that fear of movement/reinjury was lower in individuals in the absence of functional ankle instability although they experienced ankle sprain (FI; TSK=38.6±4.5, AFAQ=27.4±6.2, NFI; TSK=35.7±5.6, AFAQ=24.5±6.6). The fear of movement/reinjury had correlation with ankle joint laxity only in female athletes (TSK; r=0.285, p=0.013, AFAQ; r 0=0.322, p=0.045).

Tracking of Time-Dependent Changes in Muscle Hardness After a Full Marathon.

Inami, T, Nakagawa, K, Yonezu, T, Fukano, M, Higashihara, A, Iizuka, S, Abe, T, and Narita, T. Tracking of time-dependent changes in muscle hardness after a full marathon. J Strength Cond Res 33(12): 3431-3437, 2019-We sought to identify changes in individual muscle hardness after a full marathon and to track time-dependent changes using ultrasound strain elastography (SE). Twenty-one collegiate marathon runners were recruited. Muscle hardness (i.e., strain ratio, SR) was measured using SE for the rectus femoris (RF), vastus lateralis (VL), biceps femoris (BF) long head, tibialis anterior (TA), gastrocnemius medial (GM) head, and soleus (SOL) muscles at the following time points: pre (PRE), immediately post (POST), day-1 (D1), day-3 (D3), and day-8 (D8), after a full marathon. We found that the SR decreased after the full marathon (i.e., the muscle became harder), and that the lowest SR across all measured muscles was observed on D1. Although there was no difference in the magnitude of change in SR between the muscles of the thigh, that of the MG and SOL were significantly larger than that of the TA. Muscle hardness in the vastus lateralis, biceps femoris, and SOL recovered at D8 (i.e., nonsignificant difference from PRE), whereas recovery of rectus femoris and gastrocnemius medial hardness at D8 was not observed. Thus, the degree of change in muscle hardness does not occur uniformly within the lower extremity muscles. In particular, changes in muscle hardness of the TA after a full marathon are small compared with other muscles and time-dependent changes in each muscle vary during recovery. The features of muscle hardness identified in this study will be useful for coaches when mentoring runners on proper forms and for training advisers and therapists who seek to address deficiencies in running.

The reliability, and discriminative ability of the identification of functional ankle instability questionnaire, Japanese version.

OBJECTIVE: To assess the discriminability as well as the reliability, and internal consistency of the Identification of Functional Ankle Instability questionnaire translated into Japanese (IdFAI-J). DESIGN: Cross-sectional study. SETTING: Collegiate athletic training/sports medicine clinic. PARTICIPANTS: Twenty bilingual and sixty-five collegiate athletes including participants with and without functional instability (FI). MAIN OUTCOME MEASURES: The sensitivity, specificity, test retest reliability, and internal consistency of IdFAI-J. RESULTS: The optimal cutoff score between the FI and non-FI participants was >10, with an area under the curve of 0.92. We calculated high sensitivity (0.94) and specificity (0.77) at the cutoff point. For the test-retest reliability, the intraclass correlation coefficient value of the IdFAI-J was 0.96; the standard error of measurement and minimal detectable change value was 1.69 and 3.60, respectively. Cronbach's α was 0.87; there was no improvement when a particular item was deleted from the scale. CONCLUSIONS: The IdFAI-J has excellent discriminability, test-retest reliability, and internal consistency. Hence, the IdFAI-J significantly contribute to clinical practice and future research related to ankle instability in Japan.

Sex differences in three-dimensional talocrural and subtalar joint kinematics during stance phase in healthy young adults.

The ankle joint, including the talocrural and subtalar joints, plays an important role in human locomotion. Sex differences in walking patterns among young and old adults have been studied; however, little information exists on sex-based variations in talocrural and subtalar joint kinematics during walking. Thus, the purpose of this study was to investigate sex-based differences in the talocrural and subtalar joint kinematics during walking. We obtained lateral fluoroscopic images from 10 male and 7 female healthy volunteers during stance phase, and determined the three-dimensional bone orientations using 3D-2D model-image registration techniques to compare sex-specific differences. The orientation of the tibia, talus, and calcaneus were comparable in the static reference position. Sex-based differences in the range of motion were observed in talocrural dorsi/plantar flexion, subtalar eversion/inversion and subtalar external/internal rotation while walking. The ranges of motion in talocrural dorsi/plantar flexion (male, 13 ±â€¯4°; female, 17 ±â€¯3°), subtalar eversion/inversion (male, 8 ±â€¯3°; female, 11 ±â€¯3°) and subtalar external/internal rotation (male, 5 ±â€¯2°; female, 7 ±â€¯2°) were significantly larger in females than in males. Differences in rearfoot kinematics between males and females may reflect anatomic, physiologic and locomotor differences. Greater bone rotations in the female hindfoot may predispose women to different pathologies, or merit different treatments, than men based upon subtalar and talocrural kinematics during gait.

Foot posture alteration and recovery following a full marathon run.

Prolonged running results in lowering of the foot arch and a low arch is associated with subsequent chronic injuries. Foot posture alteration and recovery following a marathon run remain unknown. Therefore, the present study aimed to evaluate foot posture alteration following a full marathon run. The three-dimensional foot posture data of 11 collegiate runners were obtained using an optical foot scanner system before, and immediately, 1 day, 3 days, and 8 days after a full marathon. The navicular height and arch height ratio significantly decreased from before to immediately, 1 day, 3 days, and 8 days after the marathon (navicular height: before, 44.2 ± 5.0 mm; immediately after, 39.4 ± 5.5 mm; 1 day, 37.7 ± 6.2 mm; 3 days, 38.7 ± 5.5 mm; 8 days, 37.6 ± 5.7 mm; arch height ratio: before, 18.4 ± 1.9; immediately after, 16.5 ± 2.5; 1 day, 15.7 ± 2.5; 3 days, 16.2 ± 2.6; 8 days, 15.6 ± 2.2, P < 0.001, respectively). By contrast, the dorsal height significantly increased from before and immediately after to 1 day after the marathon, and then significantly decreased until 8 days after the marathon (P < 0.001). These results indicate that the recovery patterns of the dorsal and navicular heights following a marathon did not coincide; the dorsal height rose temporally at 1 day after and subsequently decreased, but the navicular height decreased throughout the 8-day period after the marathon. More than one week may be necessary for sufficient foot alignment recovery from marathon-induced changes.

Analysis of the talocrural and subtalar joint motions in patients with medial tibial stress syndrome.

BACKGROUND: The rearfoot motion during sports activities in patients with the medial tibial stress syndrome (MTSS) is unknown. This study aimed to investigate the difference in kinematics of the rearfoot in MTSS patients (eight male soccer players) and control participants (eight male soccer players) during a forward step. METHODS: Sixteen male soccer players, including eight players with MTSS, participated. Forward step trials were recorded with cineradiographic images obtained at a sampling rate of 60 Hz. Geometric bone models of the tibia and talus/calcaneus were created from computed tomography scans of the distal part of one lower limb. Following a combination of approaches, anatomical coordinate systems were embedded in each bone model. The talocrural joint motion (relative motion of the talus with respect to the tibia) and subtalar joint motion (relative motion of the calcaneus with respect to the talus) were examined. RESULTS: A significantly larger range of internal/external rotation and inversion/eversion motion was observed in the subtalar joint of MTSS patients compared to healthy controls (P < 0.05) from heel contact to heel off. There were no significant differences between the MTSS patients and healthy participants in the ranges of all talocrural joint angles during the forward step. CONCLUSION: Our results indicate that the range of subtalar joint motion is greater in patients with MTSS during the stance phase of the forward step. The kinematic results obtained of this study may have important clinical implications and add quantitative data to an in vivo database of MTSS patients.

Structural deformation of longitudinal arches during running in soccer players with medial tibial stress syndrome.

The purpose of this study was to compare angular change and translational motion from the medial longitudinal arch (MLA) and lateral longitudinal arch (LLA) during running between medial tibial stress syndrome (MTSS) and non-MTSS subjects. A total of 10 subjects volunteered, comprising 5 subjects with MTSS and 5 subjects without injury (non-MTSS) as the control group. All subjects performed the test movement that simulated running. Fluoroscopic imaging was used to investigate bone movement during landing in running. Sagittal motion was defined as the angular change and translational motion of the arch. A Mann-Whitney U-test was performed to determine the differences in the measured values between the MTSS and non-MTSS groups. The magnitude of angular change for the MLA and LLA was significantly greater for subjects with MTSS than for control subjects. Translational motion of the MLA and LLA of the MTSS group was also significantly greater than that of the non-MTSS group (all p < 0.05). Soccer players with MTSS have an abnormal structural deformation of foot during support (or stance) phase of running, with a large decrease in both the MLA and LLA. This abnormal motion could be a risk factor for the development of MTSS in these subjects.

Changes in talocrural and subtalar joint kinematics of barefoot versus shod forefoot landing.

BACKGROUND: Synergetic talocrural and subtalar joint movements allow adaptation to different footwear and/or surface conditions. Therefore, knowledge of kinematic differences between barefoot and shod conditions is valuable for the study of adaptations to footwear conditions. The objective of this study was to assess the kinematic differences in the talocrural and subtalar joints during barefoot and shod landing. METHODS: Seven healthy participants (4 males and 3 females) participated in a landing trial under barefoot and shod conditions. Fluoroscopic images and forceplate data were collected simultaneously to calculate the talocrural and subtalar joint kinematics and the vertical ground reaction force. RESULTS: Upon toe contact, the plantarflexion angle of the talocrural joint during the barefoot condition was significantly larger than that during the shod condition (barefoot, 20.5 ± 7.1°, shod, 17.9 ± 8.3°, p =0.03). From toe contact to heel contact, the angular changes at the talocrural and subtalar joint were not significantly different between the barefoot and shod conditions; however, the changes in the subtalar eversion angles in the barefoot condition, from heel contact to 150 ms after toe contact, were significantly larger than those in the shod condition. CONCLUSIONS: These results suggest that footwear was able to reduce the eversion angle of the subtalar joint after heel contact during landing; the effect of wearing footwear was quite limited. Therefore, induced rearfoot kinematic alterations to prevent or manage injuries by neutral-type footwear are likely to be impractical.

Three-dimensional kinematics of the talocrural and subtalar joints during drop landing.

The bones and soft tissues of the foot act as a shock attenuator and the relative bony motions of the talocrural and subtalar joints are the subject of research interest for their roles in lower extremity pathology. Despite this interest, little information exists on the precise in vivo talocrural and subtalar joint kinematics during dynamic activities. Therefore, the purpose of this study was to quantify the three-dimensional kinematics of the talocrural and subtalar joints during landing by using single-plane fluoroscopic imaging and shape matching techniques. Three-dimensional bone positions for 6 subjects during landing from a 10 cm height were determined by using 3D-2D model-image registration techniques. The primary talocrural joint motion after toe contact was dorsiflexion with rotation ranges averaging 12° ± 7° dorsiflexion, 2° ± 2° eversion, and 3° ± 2° internal rotation. The subtalar joint exhibited similar patterns of increased dorsiflexion, eversion, and external rotation up to 150 ms after landing. The angular changes were 5° ± 3° dorsiflexion, 7° ± 3° eversion, and 6° ± 2° external rotation. This study contributes to the quantitative understanding of the function of the normal talocrural and subtalar joints and can be used for comparison with data obtained from injured feet.

Gender-based differences in the functional deformation of the foot longitudinal arch.

BACKGROUND: Gender differences in physical characteristics are associated with differing incidences of sports-related injuries. However, functional differences in the foot arch, which acts as a shock absorber under dynamic conditions, have not been investigated. OBJECTIVE: This study investigated gender-based differences in the medial and lateral longitudinal arches under static and dynamic conditions. METHODS: Eleven males and 8 females participated in this study. Radiographic images of the subjects' feet were obtained under static conditions, with and without weight bearing. In addition, each subject performed single leg landing from 10cm platform with the knee extended, and cineangiographic images in the sagittal plane were obtained during landing. RESULTS: In the weight bearing position, the medial and lateral arch angles of the females were significantly greater than those of the males, but neither of the angles differed between the males and females without weight bearing. The magnitude of the angular changes of each arch was significantly greater in the females than in the males. CONCLUSION: These results suggest that females have a greater range of arch motion than males under static and dynamic loading conditions.

Motion characteristics of the medial and lateral longitudinal arch during landing.

This study determined sagittal plane motion of the medial longitudinal arch (MLA) and lateral longitudinal arch (LLA) as well as the kinematics of the arch during landing. IRB-approved informed consent was obtained from 10 healthy male subjects (23.4 +/- 3.4 years old) who performed single leg landings from a height of 10 cm with their knee extended. The subjects were then asked to stop and balance after each landing. Each trial was recorded using cineangiography. Images were obtained at a rate of 60 Hz using a radiation exposure equivalent to 200 mA (1 ms) with an intensity of 50 kV. Simultaneous ground reaction forces were measured using a force plate. The data were analyzed using a template method. Sagittal motion was defined as the change in the angle and the translational motion of the arch. A paired t test was performed to determine the differences in the measured values between the MLA and the LLA. The magnitude of the arch angle increased with time for 80-100 ms in all subjects. The magnitude of the arch angle for the LLA was significantly larger than that for the MLA. Regarding translational motion, the motion of the MLA was larger than that of the LLA. It was clear that each longitudinal arch had a different deformation pattern in absorbing the impact on landing. The MLA had a small angular change and a moderate degree of translational motion. Conversely, the motion of the LLA was mainly an angular change with a small translational motion.