The impact of outdoor walking surfaces on lower-limb coordination and variability during gait in healthy adults

BackgroundInter-joint coordination and variability during gait provide insight into control and adaptability of the neuromuscular system. To date, coordination research has been restricted to laboratory settings, and it is unclear how these findings translate to real-world, outdoor walking environments.Research QuestionCompared to flat walking, to what extent do outdoor surfaces impact lower-limb inter-joint coordination and variability during gait, in healthy adults?MethodsData from inertial measurement units placed on the lower-back, thigh, and shank were extracted from thirty healthy young adults (15 females, 23.5 ± 4.2 years) during outdoor walking on flat (paved sidewalk); irregular (cobblestone, grass); sloped (slope-up, slope-down); and banked (banked-right, banked-left) surfaces. Sagittal joint angles for the right knee and hip were computed and partitioned by gait phase (stance and swing). Continuous Relative Phase analysis determined inter-joint coordination and variability for the knee-hip joint pair using Mean Absolute Relative Phase (MARP) and Deviation Phase (DP), respectively. One-way repeated measures ANOVAs tested surface effects. Post-hoc Bonferroni adjusted surface comparisons were assessed.ResultsSignificant knee-hip surface effects were seen during all gait phases for MARP (p < 0.001) and DP (p ≤ 0.001). Compared to flat walking, grass prompted more in-phase coordination (smaller MARP) during stance and swing phase (p ≤ 0.003). Slope-up caused more in-phase coordination during stance (p < 0.001), while slope-down caused more out-of-phase coordination during stance and swing (p ≤ 0.003), compared to the flat surface. Sloped surfaces prompted more variable (larger DP) knee-hip coordination (p ≤ 0.001), compared to flat walking during stance and swing phase.SignificanceCompared to flat walking, changes in knee-hip coordination and variability were greatest on slope-up/slope-down surfaces. This could reflect greater changes in lower-limb kinematics on sloped surfaces and/or a neuromuscular response to the demands of a more challenging task.     

Longitudinal changes in knee joint biomechanics during level walking following anterior cruciate ligament reconstruction surgery

Following anterior cruciate ligament reconstruction (ACL) patients have altered movement patterns in the reconstructed knee during walking. There is limited information about these alterations over an extended period of time. This study was designed to present a longitudinal analysis of gait patterns following ACL reconstruction surgery. Assessments of level walking were undertaken in 16 participants at a mean 10 months (initial assessment) and again at 3 years (follow-up assessment) after ACL reconstruction surgery. Kinematic and kinetic variables were analysed using a two factor (time, limb) repeated measures ANOVA. Kinematic data showed that patients were able to achieve greater extension about the reconstructed knee at follow-up than at initial assessment. The reconstructed knee was significantly less internally rotated than the contralateral knee at the initial assessment but not at follow-up. Kinetic data showed a significant increase in the external knee extension moment for the reconstructed limb over time. There were also significant increases in the external knee adduction moment for both limbs at the follow-up assessment. The external knee adduction moment was however smaller in the reconstructed knee than the contralateral knee at both assessments. The results indicate that gait variables do change over time and that measurement at a single time point may not reflect the long term outcome of ACL reconstruction surgery. The changes were however small and may not be clinically relevant. However, the consistently reduced external knee adduction moment seen about the reconstructed knee in this study may suggest that factors other than joint moments influence degenerative change over time.     

Adults with knee osteoarthritis use different coordinative strategies to transition from swing to stance compared to young asymptomatic adults

BackgroundNeuromuscular changes that occur with aging or joint pathology likely alter the coordinative strategies that adults use to walk and to recover from perturbations during gait. Differences in coordination patterns or in how coordination changes in response to a challenge may provide insight into neuromuscular targets for falls prevention interventions.Research questionDo young asymptomatic adults, older asymptomatic adults, and older adults with knee OA alter their lower extremity segment coordination differently in response to an increase in walking speed?.MethodsWe captured lower extremity kinematics using inertial measurement units as 29 participants (10 young, 10 older, 9 older with knee osteoarthritis) walked on a treadmill at self-selected preferred and faster speeds. We calculated lower extremity segment coordination and coordination variability using vector coding. We compared coordination and its variability among groups and speeds.ResultsThere were no significant interactions between group and speed. Overall group or speed differences in coordination or variability occurred mostly during terminal swing or early stance. Coordination patterns differed between young adults and adults with knee osteoarthritis in all segment couples during terminal swing and at the foot vs. shank during early stance. During these same gait cycle phases for the foot vs. shank and shank vs. thigh segment couples, coordination patterns shifted towards those of young adults when participants walked faster. Where coordination variability differed by group or speed, it was lower in the young adults than in the older adults with or without knee osteoarthritis and at faster walking speed.SignificanceOur results identified that older adults with knee osteoarthritis have a different strategy for transitioning from swing to stance compared to young adults, especially at distal limb segments. These results may help target fall prevention interventions to specific gait cycle phases or strategies.     

Altered timing of hamstring muscle action in anterior cruciate ligament deficient patients

Recent studies indicate that the hamstrings are essential antagonists in ACL deficient patients. In order to evaluate muscle coordination under physiologic conditions, nine patients with arthroscopically verified total ACL ruptures were compared with nine control volunteers. This comparison was made from electromyograms of the thigh muscles and heel contact recordings made while walking on a treadmill. While walking on a horizontal level, the patient's muscle activity did not differ from controls, but when the knee load was increased by walking uphill, the hamstring muscles in patients were activated significantly earlier than among controls. It is proposed that an altered muscle coordination is probably essential in ACL deficient patients to secure knee stability. This study suggests a new approach to investigate the coordination of muscles under physiologic conditions in ACL deficient patients, and may guide rehabilitation programs in the future.     

The association between intersegmental coordination in the lower limb and gait speed in elderly females

Human multi-segmental motion is a complex task requiring motor coordination. Uncoordinated motor control may contribute to the decline in mobility; however, it is unknown whether the age-related decline in intersegmental coordination relates to the decline in gait performance. The aim of this study was to clarify the association between intersegmental coordination and gait speed in elderly females. Gait measurements were performed in 91 community-dwelling elderly females over 60 years old. Foot, shank, and thigh sagittal motions were assessed. Intersegmental coordination was analyzed using the mean value of the continuous relative phase (mCRP) during four phases of the gait cycle to investigate phase differences in foot–shank and shank–thigh motions during a normal gait. The results showed that foot–shank mCRP at late stance had negative correlations with gait speed (r = −0.53) and cadence (r = −0.54) and a positive correlation with age (r = 0.25). In contrast, shank–thigh mCRP at late stance had positive correlations with gait speed (r = 0.37) and cadence (r = 0.56). Moreover, partial correlation, controlling age, height, and weight, revealed that foot–shank mCRP at late stance had negative correlations with gait speed (r = −0.52) and cadence (r = −0.54). Shank–thigh mCRP at late stance had a positive correlation with gait speed (r = 0.28) and cadence (r = 0.51). These findings imply that the foot–shank and shank–thigh coordination patterns at late stance relate to gait speed, and uncoordinated lower limb motion is believed to be associated with the age-related decline in cadence.     

The relationship between isokinetic quadriceps strength and laxity on gait analysis parameters in anterior cruciate ligament reconstructed knees

Gait alterations after ACL reconstruction have been reported in the literature. The current study examined a group of 14 patients who all had an ACL reconstruction with a patellar tendon autograft. Kinetic and kinematic data were obtained from the knee during walking. The flexion-extension deficit (FED) calculated from the angular difference between maximal flexion and maximal extension during the stance phase in the ACL-reconstructed and the normal knee was measured. We investigated whether these alterations in gait are related to quadriceps strength and residual laxity of the knee. It may be that patients modify their gait patterns to protect the knee from excessive anterior translation of the tibia by reducing the amount of extension during stance. On the other hand, persistent quadriceps weakness may also cause changes in gait patterns as the quadriceps is functioning as an important dynamic stabilizer of the knee during stance. Results showed that patients had a significantly higher FED value (4.9±4.0) than a healthy control group in a previous study (1.3±0.9). This is caused mainly by an extension deficit during midstance. External extension moments of the knee (T_ZMAX were significantly lower in the current patients group than in a healthy control group (T_ZMAX –0.27±0.19 Nm/kg in patients vs. –0.08±0.06 Nm/kg in controls). There were no significant correlations between quadriceps strength and gait analysis parameters. Furthermore no correlation was found between the amount of laxity of the knee and gait. The relevance of this study lies in the fact that apparently the measured gait alterations cannot be explained solely by often used biomechanical indicators such as laxity and strength. The measured gait alterations may be a result of the surgical procedure with subsequent modified motor programming.     

Downhill walking: A stressful task for the anterior cruciate ligament?

Accelerated rehabilitation after anterior cruciate ligament (ACL) reconstruction has become increasingly popular. Methods employed include immediate extension of the knee and immediate full weight bearing despite the risks presented by a graft pull-out fixation strength of 200–500 N. The purpose of this study was to calculate the tibiofemoral shear forces and the dynamic stabilising factors at the knee joint for the reasonably demanding task of downhill walking, in order to determine whether or not this task presented a postoperative risk to the patient. Kinematic and kinetic data were collected on six male and six female healthy subjects during downhill walking on a ramp with a 19% gradient. Planer net joint moments and mechanical power at the knee joint were calculated for the sagittal view using a force platform and videographic records together with standard inverse dynamics procedures. A two-dimensional knee joint model was then utilised to calculate the tibiofemoral shear and compressive forces, based on the predictions of joint reaction force and net moment at the knee. Linear envelopes of the electromyographic (EMG) activity recorded from the rectus femoris, gastrocnemius and biceps femoris muscles were also obtained. The maximum tibiofemoral shear force occurred at 20% of stance phase and was, on average, 1.2 times body weight (BW) for male subjects and 1.7 times BW for female subjects. The tibiofemoral compressive force was 7 times BW for males and 8.5 times BW for females during downhill walking. The hamstring muscle showed almost continuous activity throughout the whole of the stance phase. The gastrocnemius muscle had its main activity at heelstrike, with a second brust during the late stance phase. Knee joint shear force predictions of approximately 1000 N for a 70-kg subject greatly exceed the strength of a typical ACL graft fixation and muscular stabilisation of the knee is therefore vital to joint integrity. The hamstring muscle shows almost continuous activity during the stance phase and thereby affords some stability, but the gastrocnemius is also seen to be an important stabiliser of the knee joint in the presence of increased shear forces during early stance. Associated stability to the knee joint is indicated by compressive loadings of 7–8 times BW across the tibiofemoral joint. Whereas under normal circumstances there is sufficient dynamic joint stabilisation during downhill walking, the muscular impairment often arising postoperatively from disturbed proprioception could endanger an ACL graft. Therefore downhill walking should be avoided during the postoperative phase in order to protect the reconstruction.This research was conducted in the Department of Human Movement at The University of Western Australia. Perth during the first author's tenure as a Visiting Research Fellow supported by a scholarship of the Swiss Orthopaedic Association (SGO)     

The effects of anterior cruciate ligament reconstruction on tibial rotation during pivoting after descending stairs

Recent in vitro research suggests that ACL reconstruction does not restore tibial rotation. This study investigated rotational knee joint stability in vivo during a combined descending and pivoting movement that applies a high rotational load to the knee joint. We studied 20 ACL reconstructed patients (bone–patellar tendon–bone graft) and 15 matched controls with a six-camera optoelectronic system performing the examined movement. In the control group the results showed no significant differences in the amount of tibial rotation between the two sides. No significant differences were also found between the contralateral intact leg of the ACL group and the healthy control. However, a significant difference was found within the ACL reconstructed group and between the reconstructed and the contralateral intact leg. Therefore ACL reconstruction may not restore tibial rotation even though anterior tibial translation has been reestablished.     

Principal component analysis of knee kinematics and kinetics after anterior cruciate ligament reconstruction

This study compared the gait of 10 subjects with unilateral anterior cruciate ligament (ACL) reconstruction to a group of 12 height- and weight-matched control subjects. The analysis was based on knee flexion, adduction, and internal rotation angles and moments. The objective was to use principal component analysis (PCA) to identify knees of the ACL reconstructed subjects that fell outside normal ranges as determined by control subjects. Gait data were collected on all subjects in a motion analysis laboratory. Principal component (PC) models were developed for each gait measure based on the control subjects' data and used to assess gait waveforms of ACL reconstructed subjects. PCA allows analysis of entire gait waveforms for comparisons. In a sample of 10 ACL reconstructed subjects (7 years after surgery, on average), six of the ACL reconstructed knees had not returned to normal following surgery and eight of the contralateral knees functioned differently from controls. A majority of the differences were noted to occur in the abduction-adduction knee moment with corresponding infrequency in the differences seen in abduction-adduction rotation. PCA enabled us to identify subjects with abnormal gait waveforms as outliers relative to the normal control group.     

The effect of cognitive loading on the lower extremity movement coordination variability in patients with anterior cruciate ligament reconstruction

BackgroundThe altered coordination variability was related to anterior cruciate ligament (ACL) re-injury after ACL reconstruction (ACL-R). As motor performance is affected by the cognitive loading, understanding the interaction of cognition and coordination variability is crucial for addressing secondary injury prevention and restoring function in rehabilitation programs.Research QuestionTo investigate the lower extremity movement coordination variability asymmetry in individuals following ACL-R and determine the effects of cognitive loading on the coordination variability.MethodsTwenty-five males who received unilateral ACL-R using hamstring tendon autograft (7.4 ± 1.3 months past reconstruction). Participants performed walking without (single-task condition) and with the concurrent cognitive task (dual-task condition). The coordination variability in hip-knee coupled motion in different gait phases was calculated using vector coding technique.ResultsThe injured leg demonstrated greater coordination variability in hip flexion/knee flexion (HF/KF) during mid-stance phase (P = 0.012) than the uninjured leg in both conditions. No significant differences were observed in other phases of HF/KF variability or other measures in all phases between the injured and uninjured legs. Both legs increased the HF/KF coordination variability during loading response phase in dual-task condition than that in single-task condition (P < 0.001).SignificanceIndividuals following ACL-R demonstrated coordination variability asymmetry of sagittal plane hip-knee coupled motion. The dual cognitive task increased the coordination variability of hip flexion/knee flexion during loading response phase in individuals following ACL-R.     

Change in knee kinematics during gait after eccentric isokinetic training for quadriceps in subjects submitted to anterior cruciate ligament reconstruction

Knee kinematics after anterior cruciate ligament (ACL) reconstruction is of interest in studies evaluating the effect of training programs. Many studies have addressed knee flexion/extension but not valgus/varus movements. Considering that joint stability is a major concern in ACL reconstruction surgery, movements occurring in the frontal plane of the knee also deserve attention. Knee extensor torque was analyzed by an isokinetic dynamometer and the angular amplitudes and velocities of flexion/extension and valgus/varus movements were analyzed by goniometry during gait 9 months after ACL reconstruction. The analysis was repeated after 3 months of eccentric isokinetic training of the quadriceps in five patients. The gait pattern was also recorded for 10 healthy controls. The knee extensor torque and flexion/extension range of movement during gait increased significantly after training. However, an unexpectedly increased valgus, most pronounced during the swing phase, which may imply adverse effects on the knee, was also observed in the ACL reconstructed knee. The recorded valgus angles may however be overestimated due to crosstalk. Thus, the extent of the increased valgus, as well as the mechanisms involved and the functional and clinical implications, need clarification before eccentric training after ACL reconstruction can be generally recommended.     

The knee adduction moment in hamstring and patellar tendon anterior cruciate ligament reconstructed knees

Purpose

The external knee adduction moment during gait has previously been associated with knee osteoarthritis, and although it has been shown to be greater following anterior cruciate ligament (ACL) reconstruction surgery compared to a control group, it has not been compared between different graft types. Given that the incidence of radiographic knee osteoarthritis appears to be greater following patellar tendon compared to hamstring tendon ACL reconstruction, this study tested the hypothesis that the knee adduction moment would also be increased following patellar tendon ACL reconstruction.

Methods

In 48 male participants (16 patellar tendon graft, 16 hamstring graft and 16 controls), the external knee adduction moment was measured during level walking in a gait laboratory at mean of 10?months after surgery.

Results

There was no difference in the knee adduction moment between the hamstring and patellar tendon groups, and both patient groups had a significantly reduced knee adduction moment compared to the control group. In the hamstring group, the smaller adduction moment was associated with the patients walking with less knee varus whereas in the patellar tendon group, the smaller moment was associated with the patients walking with a decreased vertical ground reaction force.

Conclusions

These results indicate that in male patients during the early stages of recovery from ACL reconstruction, the knee adduction moment is not greater than controls for either hamstring or patellar tendon graft types. Although the knee adduction moment was similar between the two graft types, the overall magnitude of the moment was influenced by different biomechanical factors.

Level of evidence

III.     

Comparison of the Insall–Salvati ratio of the patella in patients with and without an ACL tear

The object of this prospective study is to compare the Insall–Salvati ratio between the patients who have an anterior cruciate ligament (ACL) tear and receive arthroscopic–assistant ACL reconstruction and the patients who have no ACL tear but do have an internal disorder of the knee and receive arthroscopic surgery. We prospectively and consecutively collected into two groups a total of 217 patients who had sport injuries and received arthroscopic surgery. The study group included 115 patients who had an ACL tear and received arthroscopic–assistant ACL reconstruction with middle-third bone–patella tendon–bone graft. The control group included 102 patients with internal disorders of the knee joint, including meniscus tear, plicae, or other chondral lesion, but without an ACL tear. We measured the patellar Insall–Salvati ratio [12] on the pre-operative X-ray films for all patients. The Insall–Salvati ratio in the ACL-tear study group is significantly smaller than the control group of internal disorders of the knee (0.99±0.11 vs 1.05±0.12, p=0.001). There is no significant difference in age, gender, the side of the involved knee, duration of symptoms, patella length and patella tendon length between the two groups. In conclusion, our study shows that patella infra has an association with ACL tears, and patella infra may be a risk factor for ACL tears. In patients with an ACL tear who had patella baja, the middle-third patellar tendon may not be an ideal graft for reconstruction.     

Lateral collateral ligament reconstruction using a semitendinosus graft

We evaluated 13 reconstructions of the lateral collateral ligament (LCL) of the knee associated with a reconstruction of the ACL (n=6) and PCL (n=7). In all cases the LCL was reconstructed using a semitendinosus tendon graft through a tunnel in the fibular head and fixed in anatomical insertion of LCL at lateral femoral condyle. Patients were evaluated using the IKDC form. Lateral joint opening and posterior tibial translation were studied by radiographic stress views. The follow-up average was of 60 months (38–93). In the ACL group five patient were symptoms free while one reported moderate pain after strenuous activity. The lateral stress radiographs showed lateral joint opening of 0–2 mm in five knees, and 3–5 mm in one. In the PCL group four patients were symptom free while three complained mild to moderate pain or swelling. Lateral joint opening was 0–2 mm in six knees and 3–5 in one. External rotation at 30° of flexion was 10° in one and between 0–5° in the remainder. Eleven of 13 patients returned to their preinjury level and two returned to one level lower. These findings indicate that the LCL can be successfully reconstructed with a free ST graft at the time of ACL or PCL reconstruction.     

Functional capability is enhanced with semitendinosus than patellar tendon ACL repair

The patellar and semitendinosus tendon autograft are the two most common techniques that orthopedic surgeons use to reconstruct the anterior cruciate ligament (ACL). It has not been established, however, whether either of these techniques provides a greater functional advantage to the patient. PURPOSE: To identify patients' functional capabilities after reconstruction of the ACL with a patellar or semitendinosus tendon autograft. METHODS: Forty male soccer players volunteered for the study and were assigned to three homogeneous groups: individuals who had patellar tendon reconstruction (N = 15), individuals who had semitendinosus tendon reconstruction (N = 15), and a control group (N = 10). All patients had undergone surgery 2 yr before this study and received the same rehabilitation training. The testing procedures included measurement of thigh circumference, maximal isometric strength of quadriceps and hamstrings, two- and one-legged jump, squat and gait analysis. Kinetic, kinematic, and electromyographic data were collected. RESULTS: The patellar tendon group exhibited lower (P < 0.05) coactivation of the agonist and antagonist muscles around the knee joint during the squat movement and lower stabilization- and landing degrees during the jumps. Furthermore, the patellar tendon group had a shorter stance phase and reached the first vertical maximum later with the impaired leg while walking (720.2 +/- 15.6 ms vs 740.3 +/- 14.3 ms, and 24.3 +/- 0.64% vs 22.9 +/- 0.74% of stance phase), which was not observed in the semitendinosus tendon and control groups. CONCLUSION: Functional performance is compromised in patients who undergo a patellar tendon graft compared with a semitendinosus graft, possibly due to an altered activation of the quadriceps and hamstring muscles.     

Assessing lower extremity coordination and coordination variability in individuals with anterior cruciate ligament reconstruction during walking

BackgroundDespite our knowledge of several biomechanical risk factors related to anterior cruciate ligament (ACL) injury, such as decreased knee flexion, increased knee abduction, and increased hip flexion, adduction and internal rotation during walking, jogging, and landing from a jump, the incidence of ACL tears remains high. Quantifying variability in the lower extremity provides a continuous measure of joint coordination and function that may elicit an additional aspect of ACL injury mechanisms. Research question: The aim of this study was to assess joint coordination patterns and variability in individuals following ACL reconstruction (ACLR).MethodsTwenty participants with unilateral ACLR and twenty uninjured participants matched by sex and body mass index (BMI) walked over-ground at self-selected speed. Two force plates embedded in the walking platform recorded ground reaction forces (GRF), and a motion capture system collected kinematic data. Vector coding was used to describe coordination patterns and measure coordination variability in hip-knee and knee-ankle coupled motion. Results: Individuals with ACLR had greater variability in hip-knee coordination compared to their healthy counterparts for both the reconstructed and contralateral limbs. The individuals with ACLR also exhibited altered coordination patterns, one of which was characterized by constrained hip motion.SignificanceThese results are evidence that differences in joint coordination exist between individuals with and without ACLR, even after the former are cleared to return to sport. This new insight into coordinative function after ACLR may be useful for improving rehabilitation strategies as well as identifying those at risk of injury during return to sport testing.     

Walking velocity and lower limb coordination in hemiparesis

Background/objectiveGait training at fast speed has been suggested as an efficient rehabilitation method in hemiparesis. We investigated whether maximal speed walking might positively impact inter-segmental coordination in hemiparetic subjects.MethodsWe measured thigh–shank and shank–foot coordination in the sagittal plane during gait at preferred (P) and maximal (M) speed using the continuous relative phase (CRP), in 20 healthy and 27 hemiparetic subjects. We calculated the root-mean square (CRP_RMS) and its variability (CRP_SD) over each phase of the gait cycle. A small CRP_RMS indicates in-phasing, i.e. high level of synchronization between two segments along the gait cycle. A small CRP_SD indicates high stability of the inter-segmental coordination across gait cycles.ResultsIncrease from preferred to maximal speed was 57% in healthy and 49% in hemiparetic subjects (difference NS). In healthy subjects, the main change was shank–foot in-phasing at stance (CRP_{Shank–Foot/RMS}, P, 98 ± 10; M, 67 ± 12, p < 0.001). In hemiparetic subjects, we also found shank–foot in-phasing at late stance bilaterally (non-paretic CRP_{Shank–Foot/RMS}, P, 37 ± 9; M, 29 ± 8, p < 0.001; paretic CRP_{Shank–Foot/RMS}, P, 38 ± 13; M, 32 ± 12, p < 0.001), and thigh–shank in-phasing at mid-stance in the non-paretic limb (CRP_{Thigh–Shank/RMS}, P, 57 ± 9; M, 49 ± 9, p < 0.001). CRP_{Thigh–Shank} variability diminished in the paretic limb (CRP_{Thigh–Shank/SD}, P, 18.3 ± 6.3; M, 16.1 ± 5.2, p < 0.001).ConclusionDuring gait velocity increase in hemiparesis, there is improvement of thigh–shank coordination stability in the paretic limb and of shank–foot synchronization at late stance bilaterally, which optimizes the propulsive phase similarly to healthy subjects. These findings may add incentive for rehabilitation clinicians to explore maximal velocity gait training in hemiparesis.     

Effect of walking speed on the intersegmental coordination of lower-limb segments in elderly adults

BackgroundAgeing brings profound changes in walking gait. For example, older adults reduce the modification of pelvic and trunk kinematics with walking speed. However, the modification of the coordination between lower-limb segments with age has never been investigated across various controlled speeds.Research questionIs the effect of speed on the intersegmental coordination different between elderly and young adults?MethodsNineteen senior and eight young adults walked on a treadmill at speeds ranging from 0.56 to 1.94 m s⁻¹. The motion of the lower-limb segments in the sagittal plane was recorded by cinematography. When the angles of the thigh, shank and foot during a stride are plotted one versus the other, they describe loops constraint on a plane. The coordination between lower-limb segments was thus evaluated by performing a principal component analysis between the thigh, shank and foot elevation angles. The effect of speed and age on the intersegmental coordination was examined using a two-level linear mixed model ANOVA.ResultsIn both age groups the orientation of the plane changes with speed, due to a more in-phase shank and foot motion. However, the effect of speed on the covariation plane is lessened with age.SignificanceOur results demonstrate that there is an age-related specific adjustment of the intersegmental coordination to speed. In particular, older adults restrict their repertoire of angular segment motion. These differences in coordination are mainly related to different foot-shank coordination.     

Determination of relationship between foot arch,hindfoot, and hallux motion using Oxford foot model: Comparison between walking and running

BackgroundThe foot arch plays an important role in propulsion and shock absorption during walking and running; however, the relationship among the foot arch, metatarsal locking theory, and nature of the windlass mechanism (WM) remain unclear. Research question: What are the differences in the kinematic relationship between the foot arch, hindfoot, and hallux during walking and running?MethodsRelative angles within the foot were measured in 18 healthy men using the Oxford foot model (OFM). Data for barefoot walking at a comfortable speed and rearfoot running at 2.0 m/s were collected. Angles of the forefoot relative to the hindfoot (OFM-arch), hallux relative to the forefoot (Hallux) on the sagittal plane, and hindfoot relative to the shank (Hindfoot) on three anatomical planes were obtained. The medial longitudinal arch (MLA) angle was calculated to verify that OFM-arch can substitute the MLA angle. Each parameter was subjected to cross-correlation analysis and Wilcoxon signed-rank tests to examine the relationship with OFM-arch and compare them during walking and running.ResultOFM-arch was similar to the conventional MLA projection angle in both trials (gait: 0.79, running: 0.96 p < 0.01). Synchronization of the OFM-arch and Hallux angles was higher in running than in walking (gait: −0.09, running: −0.75 p < 0.01). Hindfoot supination was unrelated to OFM-arch. Hindfoot angle on the transverse plane exhibited a moderate relationship with OFM-arch, indicating different correlations in walking and running (gait: 0.63, running: −0.68 p < 0.01).Significance: The elevation of the foot arch due to hallux dorsiflexion differed during walking and running; hence, other factors besides WM (such as intrinsic muscles) may affect the foot arch elevation during running. The hindfoot in the frontal plane does not contribute to arch raising and foot stability during running; it features different relationships with OFM-arch during walking and running.