Influence of ankle invertor muscle fatigue on workload of the lower extremity joints during single-leg landing in the sagittal and frontal planes

BACKGROUND

Insufficient rigidity of the foot owing to its ligaments and muscles can decrease the attenuation of the ground reaction force during landing. Therefore, dysfunction of the ankle invertors may increase the proximal joint load during landing.

RESEARCH QUESTION

What are the effects of the fatigued ankle invertors on workload in the lower extremity joints during single-leg landing?

METHODS

Twenty-seven young adults (13 men and 14 women) performed landing trials in the forward and medial directions before and after exercise-induced fatigue of the ankle invertors. The exercise consisted of repeated concentric and eccentric ankle inversions until the maximum torque was below 80% of the baseline value. Negative joint workload during the landing tasks was calculated for the hip, knee, and ankle in the sagittal and frontal planes. Additionally, lower extremity work (the sum of the work of the hip, knee, and ankle) was calculated.

RESULTS

Invertor fatiguing exercise resulted in a significant increase in negative joint work in the frontal and sagittal plane hip and the frontal plane knee during medial landing, whereas no significant change in negative joint work was observed during forward landing.

SIGNIFICANCE

These findings suggested that ankle invertor dysfunction may induce a high load on the proximal joints and have direction-specific effects.

Biomechanical gait analysis and rehabilitation in a traumatic hallux deficit patient: a case report

BACKGROUND

The hallux plays a crucial role in maintaining standing balance and facilitating forward and backward movements during gait.

CASE PRESENTATION

A 21-year-old Japanese patient, suffering from a traumatic hallux deficit with only a portion of the basal phalanx intact, underwent rehabilitation treatment. The thenar area exhibited instability, leading to impaired balance and walking difficulties. Biomechanical assessment revealed the need for a rehabilitation strategy for the foot, as well as the knee, hip, and trunk. A rehabilitation protocol was designed to enhance medial foot loading during walking and standing, including balance and trunk strength training. After a 12-week rehabilitation period, the patient's gait showed significant improvement. Specifically, the load response and single-support phases of the gait cycle on the affected side increased from 46.9% to 49.3%, while the pre-swing phase decreased from 14.6% to 11.6%. The vertical component of the ground reaction force rose from 599.8 to 647.5 N. The enhanced stability from balance training and increased muscle strength contributed to the patient's improved walking and balance.

CONCLUSION

A patient with a traumatic hallux deficit underwent conservative treatment through strategic rehabilitation according to biomechanical assessment. This case report underscores the value of biomechanical gait analysis in the conservative management of similar conditions.

Age-related changes in muscle thickness, echo intensity and shear modulus of the iliocapsularis

PURPOSE

This study aimed to clarify age-related changes in the iliocapsularis (IC) using indicators of quantity, quality, and mechanical properties. We also compared the age-related changes in the IC and other hip muscles.

METHODS

Eighty-seven healthy women (ages: 21-82 years, mean age: 45.9 ± 15.7 years) participated in the experiment. We measured thickness, echo intensity, and shear modulus of the IC, iliacus muscle, rectus femoris, and the thickness and shear modulus of the hip joint capsule. Spearman's rank correlation coefficient was used to measure the association of age with variables measured in the muscles and joint capsule.

RESULTS

Thickness of the iliacus muscle and rectus femoris decreased significantly with age, but the thickness of the IC and hip joint capsule showed no significant correlation. The echo intensities of the IC, iliacus muscle, and rectus femoris were positively correlated, which increased with age. Furthermore, the shear modulus of the iliacus, rectus femoris, and hip joint capsule showed an increase with age, whereas the shear modulus of the IC exhibited no correlation with age.

CONCLUSION

The muscle quality of the IC changed significantly, unlike that of the iliacus or rectus femoris. Additionally, the correlation with echo intensity was relatively weaker in the IC compared with the iliacus or rectus femoris.

Identifying Muscle Function-based Phenotypes Associated With Radiographic Progression of Secondary Hip Osteoarthritis

OBJECTIVE

The purposes of our study were to (1) identify muscle function-based clinical phenotypes in patients with hip osteoarthritis (OA) and (2) determine the association between those phenotypes and radiographic progression of hip OA.

DESIGN

Prospective cohort study.

SETTING

Clinical biomechanics laboratory of a university.

PARTICIPANTS

Fifty women patients with mild-to-moderate secondary hip OA (N=50) were recruited from the orthopedic department of a single institution.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Two-step cluster analyses were performed to classify the patients, using hip flexion, extension, abduction, and external/internal rotation muscle strength (cluster analysis 1); relative hip muscle strength to total hip strength (ie, hip muscle strength balance; cluster analysis 2); and both hip muscle strength and muscle strength balance (cluster analysis 3) as variables. The association between the phenotype and hip OA progression over 12 months (indicated by joint space width [JSW] >0.5 mm) was investigated by logistic regression analyses. Hip joint morphology, hip pain, gait speed, physical activity, Harris hip score, and SF-36 scores were compared between the phenotypes.

RESULTS

Radiographic progression of hip OA was observed in 42% of the patients. The patients were classified into 2 phenotypes in each of the 3 cluster analyses. The solution in cluster analyses 1 and 3 was similar, and high-function and low-function phenotypes were identified; however, no association was found between the phenotypes and hip OA progression. The phenotype 2-1 (high-risk phenotype) extracted in cluster analysis 2, which had relative muscle weakness in hip flexion and internal rotation, was associated with subsequent hip OA progression, even after adjusting for age and minimum JSW at baseline (adjusted odds ratio [95% confidence interval], 3.60 [1.07-12.05]; P=.039).

CONCLUSION

As preliminary findings, the phenotype based on hip muscle strength balance, rather than hip muscle strength, may be associated with hip OA progression.

Synergistic Dominance Induced by Hip Extension Exercise Alters Biomechanics and Muscular Activity During Sprinting and Suggests a Potential Link to Hamstring Strain

ABSTRACT

Iguchi, J, Hojo, T, Fujisawa, Y, Kuzuhara, K, Yanase, K, Hirono, T, Koyama, Y, Tateuchi, H, and Ichihashi, N. Synergistic dominance induced by hip extension exercise alters biomechanics and muscular activity during sprinting and suggests a potential link to hamstring strain. J Strength Cond Res 37(9): 1770-1776, 2023-Hamstring strain is likely to occur during the late swing phase or the first half of the stance phase in sprinting. During the late swing phase, the hamstrings and gluteus maximus (Gmax) contract eccentrically to decelerate the lower limb. We hypothesized that, when the Gmax becomes dysfunctional because of delayed onset muscle soreness (DOMS), the hamstring workload is increased (i.e., there is synergetic dominance), which could lead to an increased risk of strain. A total of healthy 15 male undergraduate or graduate students (age 23.1 ± 1.28 years) were recruited to perform exercises and maximal sprints. On day 1, before subjects performing DOMS-causing exercises, and on day 3, while subjects were experiencing DOMS in the Gmax, lower-limb biomechanical and muscle activity data were recorded using a motion analysis system and electromyography (EMG), respectively. Data were analyzed and compared between day 1 and day 3. Hip flexion angle on day 3 was significantly lower than that on day 1, but the opposite was true for the knee flexion angle (P < 0.05). Vastus medialis (VM), biceps femoris (BF), and Gmax muscle activities on day 3 were significantly higher than those on day 1 (P < 0.05). Peak propulsive forces on day 3 were significantly higher than those on day 1 (P < 0.05). Kinematic changes such as decreased hip flexion angle and EMG changes such as increased BF EMG activity on day 3 to compensate for the loss of function of the Gmax may potentially increase the risk of hamstring strain.

Effect of 8-week Shoulder External Rotation Exercise with Low Intensity and Slow Movement on Infraspinatus

OBJECTIVE

Generally, low-intensity training is recommended as selective training of the infraspinatus muscle. This study aimed to investigate whether an 8-week intervention of low-intensity, slow-movement, external rotation exercise of the shoulder led to an increase in muscle strength with shoulder external rotation and cross-sectional area (CSA) infraspinatus muscle.

METHODS

Sixteen healthy male volunteers were randomly assigned to the low-intensity and slow-movement (LS) group (N = 8) or the normal-intensity and normal-speed (NN) group (N = 8). The LS and NN groups performed shoulder external rotation exercises with low intensity and slow movement, and normal intensity and normal speed, respectively. The exercise session consisted of three sets of 10 repetitions, which were performed three times per week for 8 weeks. We measured the CSA of the infraspinatus and muscle strength of the shoulder external rotation before and after the 8-week intervention.

RESULTS

A significant increase in infraspinatus CSA from baseline to 8 weeks was found in the LS group (7.3% of baseline) but not in the NN group. No significant differences were found in the muscle strength of shoulder external rotation.

CONCLUSION

Our results suggest that low-intensity exercise of the infraspinatus is effective for muscle hypertrophy when performed with slow movement. This finding may help patients who should avoid excessive stress in the early phase of rehabilitation.

Effect of age on shear modulus, muscle thickness, echo intensity of the upper limb, lower limb, and trunk muscles in healthy women

PURPOSE

This study aimed to examine the effect of age on the mechanical properties, muscle size, and muscle quality in the upper and lower limb and trunk muscles.

METHODS

We evaluated the shear modulus (G), muscle thickness (MT), and echo intensity (EI) of the upper and lower limb and trunk muscles of 83 healthy women (21-83-year-old). The G values of some limb muscles were measured in relaxed and stretched positions.

RESULTS

Regarding the effect of age on G at the distinct positions, the G of the upper limb muscles were not significantly correlated with age in the relaxed and stretched positions. In contrast, the G of the iliacus showed a significant negative correlation in both positions. Additionally, the G of the rectus femoris had a significant negative correlation only in the relaxed position. Regarding differences among body parts, the G of the lower limb and oblique abdominal muscles showed a significant negative correlation, but no correlation in the upper limb, rectus abdominis, and back muscles. Moreover, MT showed a significant negative correlation with age in the lower limb, abdominal, and erector spinae muscles, but no correlation was detected in the upper limb and lumbar multifidus muscles. EI had a significant positive correlation in all the muscles.

CONCLUSION

The effect of age on G depended on body parts, and the G of the lower limb and oblique abdominal muscles negatively associated with age. Additionally, G in the relaxed position may be more susceptible to aging than G in the stretched position.

Properties of the iliotibial band and their relationships with gait parameters among patients with knee osteoarthritis

This study aimed to determine the thickness and stiffness of the iliotibial band (ITB) in patients with knee osteoarthritis (KOA) and to identify the gait parameters that are associated with ITB properties. Eighteen female patients with radiographically diagnosed medial KOA and knee pain (age: 69.7 ± 5.9 years, body mass index: 23.0 ± 3.1 kg/m² ) and 22 age-matched female individuals without knee pain (age: 69.1 ± 7.0 years, body mass index: 21.6 ± 3.6 kg/m² ) were included. Shear wave elastography images were obtained at the height of the proximal pole of the patella with the participants in the supine position, and the ITB thickness and shear wave velocity, which is a surrogate measure of stiffness, were calculated. In patients with KOA, the knee and hip joint angles and moments during walking were calculated using a motion analysis system. The shear wave velocity was significantly higher in patients with KOA than in asymptomatic adults (11.3 ± 1.0 vs. 10.0 ± 1.8 m/s, respectively; p = 0.010); however, the thickness did not differ between them (2.1 ± 0.3 vs. 2.0 ± 0.3 mm, respectively; p = 0.705). The time-integral value of the knee adduction moment (β = 0.507, p = 0.032) and maximum value of the hip flexion moment (β = 0.498, p = 0.036) were associated with the shear wave velocity. Meanwhile, no parameters were associated with the thickness. The ITB was stiffer in patients with KOA than in asymptomatic adults; such a stiffer ITB was associated with greater knee adduction and hip flexion moments during walking. Clinical Significance: Greater mechanical loading was associated with a stiffer ITB in patients with KOA.

Validity of the frame subtraction method in dynamic postural stability

Background

The movement of targeted subjects can be calculated using the frame subtraction method. However, the validity of this evaluation method of dynamic postural stability has not been clarified yet. This study aimed to verify the validity of the evaluation method for jump landing using the frame subtraction score based on the ground reaction force (GRF).

Methods

Twenty subjects performed single-leg jump landing, and their dynamic postural stability index (DPSI), medial‒lateral stability index (MLSI), anterior‒posterior stability index, and vertical stability index (VSI) were calculated from the GRF. Simultaneously, motion images were captured using digital video cameras in the sagittal and frontal planes. After the motion images were analyzed using the frame subtraction method, the frame subtraction scores in the frontal, sagittal, and combined planes were calculated. To confirm its validity, the relationship between the frame subtraction scores and GRF parameters was investigated using Pearson's correlation analysis.

Results

The frame subtraction scores in the frontal and combined planes were significantly correlated with the DPSI, MLSI, and VSI (r = 0.46–0.75, P < 0.05).

Conclusions

Therefore, the frame subtraction method could be applied to the evaluation of dynamic postural stability. Markerless systems are deemed useful in clinical practice.

Changes in kinematic synergy in older adults during walking: A two-year follow-up study

BACKGROUND

A well-controlled center of mass (CoM) in a coordinated segmental manner is required during gait. A synergy index that quantifies the strength of the synergistic control of the body segments that control the CoM can be evaluated using uncontrolled manifold (UCM) analysis. Several studies have compared the synergy index between older and younger adults; however, contradictory results have been found regarding age-related changes in the synergy index. Moreover, no study has investigated these changes longitudinally.

RESEARCH QUESTION

To evaluate age-related changes in the synergy index to control the CoM during gait in a longitudinal study.

METHODS

Twenty-five older adults participated at a baseline visit. The gait task at the two-year follow-up was completed by 16 older adults. Participants walked on a 6-m walkway at baseline and the two-year follow-up, and kinematic data were collected. Using UCM analysis, the synergy indices controlling CoM in the mediolateral and vertical directions were evaluated at baseline and follow-up. We also evaluated the Timed Up and Go (TUG) test and the strength of the knee extensor at both periods.

RESULTS

We found that TUG was significantly slower at follow-up; however, no difference was found in muscle strength. The synergy index in the mediolateral direction increased significantly after two years; such increases were found in individuals with decreased gait speed.

SIGNIFICANCE

This study showed that changes in gait patterns, including decreasing gait speed and increasing segmental coordination, may be important for gait with appropriate postural control relative to the environment and dynamic stability of the body in individuals with low functional mobility.

Age- and sex-related differences of muscle cross-sectional area in iliocapsularis: a cross-sectional study

Background

This study aimed to determine in how many individuals the iliocapsularis muscle (IC) could be identified on magnetic resonance imaging (MRI) and whether age and sex are associated with the cross-sectional area (CSA) of the IC.

Methods

Thirty-seven healthy younger adults and 40 healthy older adults were assigned to four groups: 1) 20 younger men; 2) 17 younger women; 3) 20 older men; and 4) 20 older women. The CSAs of the IC, IP, the rectus femoris (RF) and the quadriceps (QUAD) were quantified on an axial MRI.

Results

The number of individuals with the identified IC was n = 17 (85.0%) of 20 younger men, n = 15 (88.2%) of 17 younger women, n = 18 (90.0%) of 20 older men, and 19 (95.0%) of 20 older women. Our results showed the main effect of sex, but not age, in the CSA of the IC. The men-groups had larger CSA of the IC than the women-groups; however, no difference in CSA of the IC was found between the younger and older groups. Meanwhile, the main effects of age and sex were found for the IP, RF, and QUAD; thus, younger or men groups have larger CSAs of the three muscles than the older or women groups. The IC muscle can be discriminated in 85% – 95% of healthy individuals.

Conclusion

Although sex and age are associated with the CSA of lower-limb muscles other than the IC, only sex is associated with the CSA of the IC.

Properties of triceps surae and Achilles tendon in forefoot and non-forefoot strike runners

BACKGROUND

The purpose of this study was to compare the properties of the triceps surae and Achilles tendon of forefoot strike runners and non-forefoot strike runners.

METHODS

Fourteen male college forefoot strike runners and 11 non-forefoot strike runners participated in this study. The shear elastic moduli and cross-sectional areas of the medial and lateral gastrocnemius, soleus, and Achilles tendon were measured. Passive ankle joint stiffness, maximum voluntary isometric contraction on plantar flexion and rebound jump index were also measured.

RESULTS

Forefoot strike runners had higher shear elastic moduli of the medial and lateral gastrocnemius, higher passive ankle joint stiffness, higher rebound jump index, and greater crosssectional area of the gastrocnemius and Achilles tendon than non-forefoot strike runners.

CONCLUSIONS

These findings suggest that forefoot strike runners have different mechanical properties in the gastrocnemius muscles, and different morphological properties in the Achilles tendon and gastrocnemius muscles, compared with non-forefoot strike runners.

The effect of Liquid ice after high-intensity exercise on muscle function compared to Block ice

Cryotherapy is used to recover muscle damage after exercise and to treat acute sports injuries. Liquid ice (LI) can keep cold for a long time, and is assumed more effective than block ice (BI). From this, the aim of this study was to investigate the effects of LI on the change of passive stiffness (PS) as muscle function and to validate the effectiveness of LI compared to BI. We performed the experiment as part of a case series of verification of the effects of cryotherapy. 22 healthy men (target area: right leg) were randomized to two groups: LI group and BI group. PS was measured three times during experiment protocol, pre: before exercise; post; after treating each cryotherapy after exercise; 48h: 48 hours after pre. Statistical analysis compared the PS, the amount of change in PS, and the rate of change in PS between the two groups. The rate of change between pre and 48h in LI was significantly lower compared to that in BI (p = 0.03). There was no significant difference regarding other results between groups. It revealed that the difference of effect between LI and BI for PS of muscles after high-intensity exercises. These results could be helpful for the choice of intervention for reducing muscle stiffness after exercise and at sports field.

Influence of stance width and toe direction on medial knee contact force during bodyweight squats

Squats are frequently performed to strengthen the quadriceps (Quad) and gluteus maximus (GM) in sports and clinical fields. Since the squat itself produces a large knee contact force, clarifying the relationship between the squat techniques and the knee contact force is important. However, the influence of different squat techniques on the medial knee contact force (KCFmed), which would result in knee disease, remains unclear. This study aimed to investigate the influence of various squat techniques on KCFmed during bodyweight squats. Since muscle strengthening by the squat is inevitable, we additionally aimed to explore the effect of a different squat technique on the quadriceps (Quad) and gluteus maximus (GM) forces. Twelve healthy adults performed squats with different stance widths (narrow stance, NS; middle stance, MS; and wide stance, WS) and different toe directions (0° of forefoot abduction - NEUT and 30°forefoot abduction - OUT). The KCFmed, Quad force, and GM force were computed using a musculoskeletal model with marker trajectories and ground reaction forces. The KCFmed in NS was significantly larger than that in MS and WS, and KCFmed in OUT was significantly larger than that in NEUT. The Quad force in OUT was significantly larger than that in the NEUT, and the GM force significantly became larger as the stance width became narrower. These findings suggest that squats in MS and NEUT may be suitable for reducing KCFmed while maintaining the Quad and GM forces.

Estimating thigh skeletal muscle volume using multi-frequency segmental-bioelectrical impedance analysis

Background

The primary aim of this study was to investigate whether using the extracellular water/intracellular water (ECW/ICW) index and phase angle combined with segmental-bioimpedance analysis (BIA) improved the model fitting of skeletal muscle volume (SMV) estimation. The secondary aim was to compare the accuracy of segmental-BIA with that of ultrasound for estimating the quadriceps SMV measured with MRI.

Methods

Seventeen young men (mean age, 23.8 ± 3.3 years) participated in the study. The T-1 weighted images of thigh muscles were obtained using a 1.5 T magnetic resonance imaging (MRI) scanner. Thigh and quadriceps SMVs were calculated as the sum of the products of anatomical cross-sectional area and slice thickness of 6 mm across all slices. Segmental-BIA was applied to the thigh region, and data on the 50-kHz bioelectrical impedance (BI) index, ICW index, ECW/ICW index, and phase angle were obtained. The muscle thickness index was calculated as the product of the mid-thigh muscle thickness, determined using ultrasound, and thigh length. The standard error of estimate (SEE) of the regression equation was calculated to determine the model fitting of SMV estimation and converted to %SEE by dividing the SEE values by the mean SMV.

Results

Multiple regression analysis indicated that the combination of 50-kHz BI and the ECW/ICW index or phase angle was a significant predictor when estimating thigh SMV (SEE = 7.9 and 8.1%, respectively), but were lower than the simple linear regression (SEE = 9.4%). The ICW index alone improved the model fitting for the estimation equation (SEE = 7.6%). The model fitting of the quadriceps SMV with the 50-kHz BI or ICW index was similar to that with the skeletal muscle thickness index measured using ultrasound (SEE = 10.8, 9.6 and 9.7%, respectively).

Conclusions

Combining the traditionally used 50-kHz BI index with the ECW/ICW index and phase angle can improve the model fitting of estimated SMV measured with MRI. We also showed that the model suitability of SMV estimation using segmental-BIA was equivalent to that on using ultrasound. These data indicate that segmental-BIA may be a useful and cost-effective alternative to the gold standard MRI for estimating SMV.

Immediate effects of stance and swing phase training on gait in patients with stroke

To compare the effects of gait trainings targeting the stance (stance training) and the swing phases (swing training) among the subjects with stroke, and quantify the characteristics in the subjects who benefitted from either the stance training or the swing training. Sixteen subjects with stroke performed the stance training, which focused on the center of pressure to move from the heel to the forefoot, and the swing training, which focused on the improvement of hip flexion in the swing phase. To investigate the immediate effects of the stance training and the swing training, the instrumented gait analysis was performed before and after training. To quantify the characteristics, subjects were divided into two groups based on the gait speed change. These two groups were compared using clinical examinations. After the stance training, the center of pressure displacement of the paretic limb was increased compared with the swing training. Subjects who benefitted from the stance training had slower Timed Up and Go and weaker paretic hip muscle strength than those who benefitted from the swing training. Stance training may be more effective in subjects with slower Timed Up and Go outcomes and weaker hip muscles.

Influence of simulated hip muscle weakness on hip joint forces during deep squatting

This study aimed to determine the effects of simulated hip muscle weakness on changes in hip joint forces during deep squat motion. Ten healthy individuals performed squat motion at three different positions (0° foot angle [N-squat], 10° toe-in [IN-squat], and 30° toe-out [OUT-squat]). A scaled musculoskeletal model for each participant was used to calculate the muscle and hip joint forces. For each hip muscle, models of full strength, mild muscle weakness (15% decrease), and severe muscle weakness (30% decrease) were created. The muscles affecting the hip joint forces were identified, and the rate of change in the joint forces was compared among the three squat conditions. The anterior hip joint force was increased in the muscle weakness models of the inferior gluteus maximus (iGlutMax) and iGlutMax+deep external rotator (ExtRot) muscles. With 30% muscle weakness of these muscles, statistically significant differences in the rate of increase in the anterior joint force were observed in the following order: IN-squat (iGlutMax, 29.5%; iGlutMax+ExtRot, 41.4%), N-squat (iGlutMax, 18.3%; iGlutMax+ExtRot, 27.8%), and OUT-squat (iGlutMax, 5.6%; iGlutMax+ExtRot, 9.3%). OUT-squat may be recommended to minimize the increase in hip joint forces if accompanied by hip muscle weakness.

The effects of knee pain on knee contact force and external knee adduction moment in patients with knee osteoarthritis

Knee osteoarthritis (OA) is a major cause of knee pain, leading to physical dysfunction. External knee adduction moment (KAM), a surrogate measure of knee contact force (KCF) in the medial compartment, is related to knee pain, but the association between KCF and pain severity remains unclear. This study aimed to reveal the differences in KCF due to pain severity. Twenty-eight patients with knee OA were evaluated knee symptoms including pain severity via the Knee Society Score. Based on the median symptom score, 17 points in this study, subjects were classified as having Mild symptomatic OA (n = 15) and Severe symptomatic OA (n = 13). Subjects walked three times at a comfortable speed along a six-meter walkway, and we calculated KAM during the stance phase. KCF magnitude and distribution were also computed using the subject-specific musculoskeletal model, considering physical characteristics such as the femorotibial angle measured by X-ray. No differences in physical characteristics such as femorotibial angle and gait speed were found by symptom severity, whereas KAM and medial KCF at minimum and second peak in Severe symptomatic OA patients were significantly greater than those in Mild symptomatic OA. A significant medial shift of KCF in Severe symptomatic OA was also seen at first peak and minimum. Severe symptomatic OA had a greater medial KCF and medial shift of KCF. Detailed evaluations of KCF magnitude and distribution in addition to KAM would provide crucial information on knee contact force in relation to symptom severity.

Strategies for increasing gait speed in patients with hip osteoarthritis: their clinical significance and effects on hip loading

Background

Changes in gait speed are required in various situations and can be achieved by changing stride length, cadence, or both. Differences in strategies for increasing gait speed may have different effects on hip joint and physical function. The purpose of this study was to determine the effects of strategies for increasing gait speed on hip pain, physical function, and changes in hip loading during gait in patients with hip osteoarthritis (OA). We hypothesized that patients who increase gait speed mainly by increasing cadence would have lesser hip pain, a higher physical function, and a lower rate of increase in hip moments with increasing gait speed.

Methods

Forty-seven patients with secondary hip OA (age, 48.3 ± 11.0 years) were included. Gait speed, stride length, cadence, and peak and impulse of the hip moments were measured during gait at self-selected normal and fast gait speeds. The patients were classified as types S (with mainly increasing stride length, n = 11 [23.4%]), C (with mainly increasing cadence, n = 23 [48.9%]), and SC (with increasing stride length and cadence, n = 13 [27.7%]) according to whether they used changes in stride length and/or cadence to transition from normal to fast gait. Hip pain, physical function, and hip moment changes during gait were compared between types.

Results

The physical function was higher in types C (38.0 ± 8.8, P = 0.018) and SC (40.6 ± 8.5, P = 0.015) than in type S (28.2 ± 7.8), even after adjustment for age and minimum joint space width. Hip pain was not significantly different between types. The robustness of these results was confirmed with sensitivity analysis. The rates of increases in peak external hip adduction (P = 0.003) and internal rotation moments (P = 0.009) were lower in type C than in type SC.

Conclusions

Type C tended to suppress the increase in hip moments during fast gait. Types C and SC, which included increased cadence, maintained higher physical function levels than type S. Encouraging the use of cadence-increasing strategy may be useful for reducing hip loading and maintaining physical function in patients with hip OA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-021-02514-x.

The relation between kinematic synergy to stabilize the center of mass during walking and future fall risks: a 1-year longitudinal study

BACKGROUND

Incorrect body weight shifting is a frequent cause of falls, and the control of the whole-body center of mass (CoM) by segmental coordination is essential during walking. Uncontrolled manifold (UCM) analysis is a method of examining the relation between variance in segmental coordination and CoM stability. However, no prospective cohort study has thoroughly investigated how variance in segmental configurations to stabilize the CoM relates to future falls. This study explored whether variance to stabilize the CoM was related to future falls.

METHODS

At the baseline visit, 30 community-dwelling older adults walked 20 times on a 6-m walkway. Using kinematic data collected during walking by a three-dimensional motion capture system, UCM analysis was performed to investigate how segmental configuration contributes to CoM stability in the frontal plane. One year after the baseline visit, we evaluated whether the subjects experienced falls. Twelve subjects had experienced falls, and 16 had not. Comparisons of variance between older adults with and without falls were conducted by covariate analysis.

RESULTS

No significant differences in variance were found in the mediolateral direction, whereas in the vertical direction, older adults with fall experiences had a greater variance, reflecting an unstable CoM, than those with no fall experiences.

CONCLUSIONS

We verified that the high variance in segmental configurations that destabilize the CoM in the vertical direction was related to future falls. The variables of UCM analysis can be useful for evaluating fall risk.

Verification of validity of gait analysis systems during treadmill walking and running using human pose tracking algorithm

BACKGROUND

The human tracking algorithm called OpenPose can detect joint points and measure segment and joint angles. However, the validity of gait analysis using OpenPose has not been examined yet.

RESEARCH QUESTION

What is the validity of OpenPose-based gait analysis?

METHODS

Twenty-four healthy young people participated in this study. The participants were assessed during walking and running. Pelvic segment angles, and hip, knee, and ankle joint angles during treadmill walking and running were measured using VICON. Simultaneously, images were captured using digital cameras from the right and back sides. After processing with OpenPose, the corresponding angles were measured from the estimated joint points. To validate these estimations, linear regression analysis was performed, and intraclass correlation coefficients [ICCs (2, 1)] between the data obtained by OpenPose and VICON were calculated. Furthermore, the agreement between the data obtained by OpenPose and VICON was assessed by Bland-Altman analysis.

RESULTS

For most ranges of motion (ROM) in the sagittal plane, the hip, knee, and ankle joints had large coefficients of determination, without proportional biases. For most peak angles in the sagittal plane, the knee and ankle joints had large coefficients of determination without proportional biases, although the hip joint had nonsignificant coefficients of determination and proportional biases. In particular, for the hip flexion-extension ROM and peak knee flexion angle during running and the knee ROM during slow walking, the ICCs showed good to excellent agreement. However, for the parameters of the pelvis and hip joint in the frontal plane, there were nonsignificant coefficients of determination and poor ICCs with fixed and proportional biases.

SIGNIFICANCE

The lower limb ROM in the sagittal plane during gait can be measured by the OpenPose-based motion analysis system. The markerless systems have the advantage of being more economical and convenient than conventional methods.

Differences in shear elastic modulus of the latissimus dorsi muscle during stretching among varied trunk positions

The latissimus dorsi (LD) can be divided into the upper, middle, and lower parts, but the effective stretching positions for each part are unknown. In this study, we aimed to investigate effective trunk positions for stretching of the LD. A total of 14 healthy males participated in this study. The following seven trunk positions were chosen as the LD stretching positions; upright of the trunk (Baseline), flexion of the trunk (Flex), contralateral bending of the trunk (LB), contralateral rotation of the trunk (Rot), flexion and contralateral bending of the trunk (Flex + LB), flexion and contralateral rotation of the trunk (Flex + Rot), and contralateral bending and contralateral rotation of the trunk (LB + Rot). Maximal elevation of the upper limb was passively added to all positions. The shear elastic modulus, used as the index of muscle elongation, was measured at the four parts (upper, middle, lower, distal parts) of the LD. The shear elastic moduli showed obviously high values in Rot and LB + Rot at the upper, middle, and distal parts, and also in LB, Rot, and LB + Rot at the lower part. These findings suggest that contralateral trunk rotation, or a combination of contralateral trunk bending and rotation are effective trunk positions for stretching all parts of the LD. Contralateral trunk bending was also effective for stretching the lower part of the LD.

Relation between frontal plane center of mass position stability and foot elevation during obstacle crossing

High foot elevation during obstacle crossing is viewed as a conservative strategy in older adults, but excessive foot elevation may result in large mediolateral center of mass (CoM) displacement. Since an incorrect transfer of CoM can lead to balance loss during locomotion, both appropriate foot elevation and CoM position must be controlled and coordinated by adjusting body segment positions. However, no studies have revealed time profiles of CoM position by coordinated segment movements and the relation of foot elevation with CoM position during obstacle crossing. Twenty-five healthy older adults crossed an obstacle (depth: 1 cm, width: 60 cm, height: 8 cm) during comfortable-speed walking. Synergy indices were calculated during lead- and trail-limb swing using uncontrolled manifold analysis. High synergy index values indicate a strong multi-joint kinematic synergy, or co-fluctuations in segment movements, to control CoM position. The maximum foot heights of the swing limbs were calculated as the maximum vertical distance between the most distal foot point and the ground. In the mediolateral direction, synergy index values during early lead-limb swing were significantly greater than during early trail-limb swing, and in the vertical direction, large synergy index values were found during early- and mid-swing phases. Moreover, maximum trail-foot height was correlated to vertical synergy index during early phase. CoM position was not well controlled by a kinematic synergy during trail-limb swing and the low control of CoM position was observed with great trail-foot height. The results suggest that a conservative strategy with great trail-foot height would not always be helpful for successful obstacle crossing.

Muscle size-scaled shear elastic modulus: A muscle force index independent of maximal voluntary contraction, assessed during elbow extension

Shear elastic modulus (G) can differ among individuals due to muscle size and other factors, even for constant muscle force. Inter-individual comparisons of G usually require normalization by maximal voluntary contraction (MVC), but MVC procedures may not be appropriate for certain clinical populations including those presenting with pain or other compromised functionality. This study aimed to test whether muscle size-scaled G, which does not require MVC testing, would yield stronger correlation with absolute torque than unscaled G. Twelve-healthy males performed isometric elbow extension across a range of torque magnitudes (from 5 Nm until 60% MVC). G of the triceps brachii was measured using shear wave elastography during each trial. Cross-sectional area (CSA) and muscle thickness (MT) of the triceps brachii were measured at rest. Scaled G was calculated as a product of G and CSA or MT ("G-CSA" and "G-MT", respectively). Within-individual linear regressions were conducted between absolute torque and the three force indicator variables. The regression slopes' coefficient of variation (CV) was calculated for each indicator across individuals. Between-individual correlation coefficients were calculated, after pooling all data across individuals into a single regression analysis for each indicator. Linear regression found that inter-individual slope variation increased in the following order: G-CSA, G-MT, and unscaled G (CV = 0.15, 0.18, and 0.29, respectively). Pooled-individual correlation coefficients were significantly higher in G-CSA and G-MT than in unscaled G (r = 0.948, 0.924, and r = 0.783, respectively). These results suggest that muscle size-scaled G may be more appropriate than unscaled G when comparing shear moduli across individuals.

Effects of trunk lean and foot lift exercises in sitting position on abdominal muscle activity and the contribution rate of transversus abdominis

PURPOSE

Abdominal hollowing exercise has been recommended to improve trunk stability. Trunk lean and foot lift exercises while sitting may easily promote abdominal muscle activity even in people who cannot perform abdominal hollowing consciously. The purpose of the present study was to examine the changes in abdominal muscle activity and contribution rate of the transversus abdominis muscle (TrA) when leaning the trunk and lifting the foot during sitting.

METHODS

The muscle stiffnesses (indicators of muscle activity) of the right rectus abdominis, external oblique, internal oblique, and TrA of 14 healthy men were measured during abdominal hollowing and the following nine sitting tasks: reference posture, 15° and maximal posterior trunk lean, 20° and maximal ipsilateral and contralateral trunk lean, and ipsilateral and contralateral foot lift. The TrA contribution rate was calculated by dividing the TrA stiffness by the sum of the abdominal muscles' stiffnesses.

RESULTS

The TrA stiffness was significantly higher in abdominal hollowing than in reference posture, posterior and ipsilateral trunk lean, and ipsilateral foot lift, but not higher than in contralateral trunk lean and contralateral foot lift. There was no significant difference in the TrA contribution rates between abdominal hollowing and ipsilateral or contralateral foot lift.

CONCLUSION

The contralateral trunk lean or contralateral foot lift could enhance TrA activity for people who cannot perform abdominal hollowing consciously. The contralateral foot lift could particularly be beneficial to obtain selective activity of TrA.

Verification of criterion-related validity of the evaluation method of postural stability using the frame subtraction method

It is important to quantify the postural stability. The frame subtraction method can calculate the motions of a subject, and might be easier to implement, with lower costs. However, validity of the evaluation of postural stability using this method have not been validated yet. Therefore, the purpose of this study was to verify criterion-related validity of the frame subtraction scores and the center of pressure (COP) parameters during maintenance of single leg standing. Twenty two healthy young subjects participated in this study. Motion tasks comprised right leg standing with eyes open and closed. The total length of COP displacements (LNG), Root mean square (RMS) area, anterior - posterior (AP) range, medial - lateral (ML) range were recorded using the force plate. Simultaneously, the motion images were acquired with digital video cameras from the front and right sides. After the motion images were analyzed using the frame subtraction method, the frame subtraction scores (maximum / sum of the frame subtraction score on each plane / the frontal and sagittal planes) were measured. To confirm the validity, Spearman's rank correlation coefficient between the frame subtraction scores and the COP parameters was calculated. The sum of the frame subtraction score on the frontal plane was significantly correlated with all COP displacements in the single leg standing. The result of this study indicated that the frame subtraction method could be applied to the evaluation of balance task with postural sway such as maintenance of single leg standing. The frame subtraction method is low cost and easy owing to its marker-less systems.

Verification of reliability and validity of motion analysis systems during bilateral squat using human pose tracking algorithm

BACKGROUND

The human tracking algorithm called OpenPose can detect joint points and calculate joint angles. However, the reliability and validity of OpenPose have not been clarified yet.

RESEARCH QUESTION

Are there the enough reliability and validity of OpenPose based motion analysis?

METHODS

20 healthy young subjects participated in this study. The motion task was a bilateral squat. The joint angles of the trunk, hip, knee, and ankle were calculated using OpenPose and VICON. Kinematic measurements by three-dimensional motion analysis devices were recorded using VICON. Simultaneously, the images were taken with a digital camera from the right side. After the images were processed with OpenPose, joint angles were calculated from estimated joint points. To confirm the test-retest reliability within device, intraclass correlation coefficients [ICC (1, 3)] were calculated. To confirm the validity, linear regression analysis and ICC (2, 1) between the data obtained by OpenPose and VICON were calculated. Furthermore, the agreement between the data obtained by OpenPose and VICON was assessed by Bland-Altman analysis.

RESULTS

ICCs (1, 3) of the data obtained by OpenPose and VICON were almost perfect. There were significant associations between the data obtained by OpenPose and VICON. ICCs (2, 1) between the data obtained by OpenPose and VICON were almost perfect or substantial for trunk, knee and ankle joints, and fair on the hip joint. There were fixed biases on knee and ankle joints, and proportional biases on trunk and hip joint.

SIGNIFICANCE

OpenPose based motion analysis is reliable and has the advantage of being low cost and easier to operate than conventional methods. In future, to consider the clinical utility of OpenPose, it is necessary to identify the error between the true values indicating actual joint movement and data obtained by OpenPose with its correction for fixed and proportional biases. (295 words).

Clinical phenotypes based on clinical prognostic factors in patients with secondary hip osteoarthritis: preliminary findings from a prospective cohort study

OBJECTIVES

Recently, several clinical prognostic factors for hip osteoarthritis (OA) progression such as spinal malalignment, reduced spinal mobility, and excessive daily cumulative hip loading have been identified. This study aimed to identify clinical phenotypes based on clinical prognostic factors in patients with secondary hip OA using data from prospective cohort studies and to define the clinical features of each phenotype.

METHODS

Fifty patients participated. Two-step cluster analysis was performed to identify the phenotypes using the following potential prognostic factors for hip OA progression: spinal inclination in standing, thoracolumbar spine mobility, daily cumulative hip moment, and minimum joint space width (JSW) at baseline. Comprehensive basic and clinical features (age, body mass index, hip pain, Harris hip score, JSW, radiographic hip morphology, hip impairments, spinal alignment and mobility, and gait-related variables) and ratio of progressors in 12 months were compared among the phenotypes using bootstrap method (unadjusted and adjusted for age).

RESULTS

Three phenotypes were identified and each phenotype was characterized as follows (P < 0.05): phenotype 1 (30%)-relatively young age and higher daily cumulative hip loading; phenotype 2 (42.0%)-relatively older age, reduced JSW, and less spinal mobility; and phenotype 3 (28.0%)-changed thoracic spine alignment and less spinal (especially in the thoracic spine) mobility. The ratio of progressors among the phenotypes was not statistically significantly different. These characteristics remained after adjustment for age.

CONCLUSION

Three phenotypes with similar progression risk were identified. This finding will help in designing treatment tailored to each phenotype for hip OA progression prevention.Key Points• Three phenotypes with similar progression risk were identified based on clinical prognostic factors.• Phenotype 1 was characterized by young age and higher daily cumulative hip loading.• Phenotype 2 was relatively old age and had reduced JSW and less spinal mobility.• Phenotype 3 had changed thoracic spine alignment and less thoracic spine mobility.

Gait kinematics of the hip, pelvis, and trunk associated with external hip adduction moment in patients with secondary hip osteoarthritis: toward determination of the key point in gait modification

Background

A larger daily cumulative hip loading, which is the product of the external hip adduction moment (HAM) impulse during gait and the number of steps per day has been identified as a factor associated with the progression of secondary hip osteoarthritis (OA). The cause of the increased HAM impulse in patients with hip OA has not been identified. The purpose of this study was to identify the gait parameters associated with HAM impulse during gait in patients with secondary hip OA.

Methods

Fifty-five patients (age 22–65 years) with mild-to-moderate secondary hip OA participated in this cross-sectional study. The HAM impulse during gait was measured using a three-dimensional gait analysis system. To identify the gait parameters associated with HAM impulse, hierarchical multiple regression analysis was performed. The first model (basic model) included body weight and stance phase duration. The second models included gait parameters (gait speed; ground reaction force [GRF] in frontal plane; and hip, pelvic, and trunk angle in frontal plane) and hip pain in addition to the basic model.

Results

Body weight and stance phase duration explained 61% of the variance in HAM impulse. In the second model, which took into account body weight and stance phase duration, hip adduction angle (9.4%), pelvic tilt (6.5%), and trunk lean (3.2%) in addition to GRF explained the variance in the HAM impulse. Whereas larger hip adduction angle and pelvic tilt toward the swing limb were associated with a larger HAM impulse, larger trunk lean toward the stance limb was associated with smaller HAM impulse.

Conclusion

In patients with excessive hip adduction and pelvic tilt toward the swing limb during gait, gait modification may contribute to the reduction of hip joint loading.

Gait kinematics and physical function that most affect intralimb coordination in patients with stroke

BACKGROUND

Disturbed lower limb coordination is thought to limit gait ability in patients with stroke. However, the relationship of lower limb coordination with gait kinematics and physical function has not yet been clarified.

OBJECTIVE

The purpose of the study was to clarify the gait kinematic and physical function variables that most affect intralimb coordination by using the continuous relative phase (CRP) between the thigh and shank.

METHODS

Fifteen participants with stroke were enrolled in this study. Kinematic and kinetic measurements were recorded during gait at preferred speeds. CRP was defined as the difference between the thigh and shank phase angles.

RESULTS

Stepwise analysis revealed that non-paretic CRP during the propulsive phase was a determinant of gait speed. The paretic knee extension and flexion angles were determinants of the CRP during the propulsive phase in the non-paretic limb. Stepwise analysis showed that the paretic knee extension angle was a determinant of the CRP during the propulsive phase in the paretic limb. Stepwise analysis revealed that the paretic knee extensor muscle strength was a determinant of the CRP during the propulsive phase in both limbs.

CONCLUSIONS

Our study indicates that improvement in knee movement during the stance phase may improve coordination.

The relation between limb segment coordination during walking and fall history in community-dwelling older adults

Control of the swing foot during walking is important to prevent falls. The trajectories of the swing foot are adjusted by coordination of the lower limbs, which is evaluated with uncontrolled manifold (UCM) analysis. A previous study that applied this analysis to walking revealed that older adults with fall history had compensatorily great segment coordination to stabilize the swing foot during normal walking. However, it is unknown whether the increase in segment coordination helps for preventing incident falls in the future. At baseline measurement, 30 older adults walked for 20 times at a comfortable speed. UCM analysis was performed to evaluate how the segment configuration in the lower limbs contributes to the swing foot stability. One year after the baseline visit, we asked the subjects if there were incident falls through a questionnaire. The univariate and multivariable logistic regression analyses were performed to assess the association between the index of segment coordination and incident falls with and without adjustment for gait velocity. Twenty-eight older adults who responded to the questionnaire were classified into older adults (n = 12) who had the incident fall and those (n = 16) who did not have falls. It was revealed that older adults who increased the segment coordination associated with swing foot stability tended to experience at least one fall within one year of measurement. The index of the UCM analysis can be a sensitive predictor of incident falls.

Gait- and postural-alignment-related prognostic factors for hip and knee osteoarthritis: Toward the prevention of osteoarthritis progression

Osteoarthritis (OA) is a chronic progressive disease, and thus, prevention of this progression is an important issue. Currently, there is little evidence of the effect of exercise therapy for the prevention of hip and knee OA progression. An understanding of prognostic factors is the basis for the prevention of progression. Previous research indicates that in case of knee OA, abnormalities in knee alignment (varus or valgus) while standing, varus thrust during walking, increased knee flexion in the early stance phase, abnormal displacement of the femur in relation to the tibia, and an increase in knee adduction and flexion moment are risk factors for disease progression. At the same time, the prognostic factors in hip OA are anterior spinal inclination while standing, decreased mobility of the thoracolumbar spine, and increased cumulative hip loading during daily walking. Further research is required to investigate these prognostic factors, particularly the modifiable factors, to analyze the relationships between these factors, and to verify the structural and clinical efficacy of modifying these factors through interventions.

Abdominal girth as an index of muscle tension during abdominal hollowing: Selecting the optimal training intensity for the transversus abdominis muscle

The abdominal hollowing technique is used for training the transversus abdominis (TrA). However, the optimal intensity of hollowing is still unclear. The objective of the present study is to verify the validity of estimating the tension of the TrA by measuring the girth of the abdomen with a tape and to determine the optimum intensity of hollowing to effectively train the TrA. Sixteen healthy males performed hollowing with an intensity of 0%, 25%, 50%, 75%, and 100%, estimated from the girth of the abdomen. The shear elastic modulus was measured for the rectus abdominis (RA), external oblique (EO), internal oblique (IO), and TrA at all intensities via ultrasonic shear wave elastography. The shear elastic modulus was considered as the index of the tension of the abdominal muscles at each intensity, and the ratio of the TrA to RA, EO, and IO respectively was calculated as the index of TrA selectivity. As the intensity of hollowing increased, the girth of abdomen decreased and tension of all the four muscles increased. The ratio of TrA to the RA, EO, and IO did not exhibit a significant variation among hollowing intensities of 25% to 100%. It is rational to estimate the tension of the TrA by measuring the girth of the abdomen. Moreover, considering both TrA contraction intensity and selectivity, abdominal hollowing performed at maximum intensity was effective for the maximum contraction training of the TrA.

Gait- and Posture-Related Factors Associated With Changes in Hip Pain and Physical Function in Patients With Secondary Hip Osteoarthritis: A Prospective Cohort Study

OBJECTIVE

To identify gait- and posture-related factors associated with changes in hip pain and physical function in patients with hip osteoarthritis (OA).

DESIGN

Prospective cohort study.

SETTING

Clinical biomechanics laboratory of a university.

PARTICIPANTS

Consecutive sampling of female patients with mild-to-moderate secondary hip OA (N=30).

MAIN OUTCOME MEASURES

Hip pain (visual analog scale) and physical function (physical component summary of the Medical Outcomes Study 36-Item Short-Form Health Survey) were measured at baseline and 12 months later. With changes in hip pain and physical function as dependent variables, linear regression analyses were performed with gait- and posture-related factors as independent variables with and without adjustment for age, joint space width, and hip pain or physical function at baseline. Posture-related factors included angles of thoracic kyphosis, lumbar lordosis, sacral inclination, spinal inclination, and spinal mobility. Gait-related factors were walking speed, steps per day, joint angles, external hip joint moment impulses, and daily cumulative hip moments.

RESULTS

Multiple linear regression analyses showed that limited hip extension (adjusted standardized B coefficient [95% confidence interval]: -0.52 [-0.88 to -0.17]) and limited external rotation angles (-0.51 [-0.85 to -0.18]) during walking were associated with the worsening of hip pain. An increased thoracic kyphosis (-0.54 [-0.99 to -0.09]), less sacral anterior tilt (0.40 [0.01-0.79]), reduced thoracic spine mobility (0.59 [0.23-0.94]), less steps per day (0.53 [0.13-0.92]), and a slower walking speed (0.45 [0.04-0.86]) were associated with deterioration in physical function.

CONCLUSIONS

Gait- and posture-related factors should be considered when assessing risk and designing preventive interventions for the clinical progression of secondary hip OA.

Mechanical energy efficiency for stepping up and down in persons with medial knee osteoarthritis

BACKGROUND

Energetic cost contributes to movement impairments observed during stair negotiation in persons with knee osteoarthritis. Specifically, the intersegmental mechanical energy exchange may be diminished in the presence of pathologies.

RESEARCH QUESTION

The purpose of this study was to evaluate mechanical energy efficiency in persons with knee osteoarthritis during stepping up and down based on mechanical energy analysis.

METHODS

Sixteen patients with medial knee osteoarthritis and 16 age-matched controls participated. A three-dimensional motion analysis system and force platforms were used to acquire biomechanical data. The participants were instructed to ascend/descend a 2-step staircase. The mechanical power exhibited during the stance phase at the lower step of the staircase were computed. Mechanical Energy Expenditure (MEE) was calculated as the integral of net joint power at each joint. Mechanical Energy Compensation (MEC) was defined as the proportion of muscle energy compensated by inter-segmental energy transfer. According to energy transfer modes, MEE and MEC were determined separately as three phases: concentric and eccentric transfer phases and no-transfer phase.

RESULTS

While stepping up, the patient group performed the task with less MEC at the ankle joint, which was observed prior to push-off. The patient group displayed less mechanical energy transfer from the shank to the foot segment. The concentric MEC at the hip joint in the late-stance phase of stepping down was lower in the patient group, which meant patients demonstrated less mechanical energy transfer from the pelvis to the thigh segment.

SIGNIFICANCE

It was disclosed that persons with knee osteoarthritis demonstrated less mechanical energy transfer while stepping up and down.

Back muscle activity and sagittal spinal alignment during quadruped upper and lower extremity lift in young men with low back pain history

BACKGROUND

Quadruped upper and lower extremity lift (QULEL) is performed for selective training of the lumbar multifidus muscle in patients with low back pain (LBP) or individuals with LBP history (LBPH). However, the activities of the back muscles and sagittal spinal alignment during QULEL are not clarified in individuals with LBPH.

RESEARCH QUESTION

This study aimed to analyze the activities of the back muscles and sagittal spinal alignment during QULEL in young male with LBPH.

METHODS

The study comprised 9 asymptomatic young men and 8 young men with LBPH. The activities of the lumbar multifidus, latissimus dorsi and thoracic erector spinae, and lumbar erector spinae muscles were measured using surface electromyography. The flexion angles of the upper and lower thoracic spine, and extension angle of the lumbar spine were measured using a 6-DF electromagnetic motion tracking system. The association with LBPH was investigated using multiple logistic regression analysis with a forward selection method, with the activities of the back muscles, sagittal spinal alignment, age, body height, and body weight as independent variables.

RESULTS

Multiple logistic regression analysis (p = 0.0002) showed that the activity of the latissimus dorsi and thoracic erector spinae muscles in the side on which the lower extremity was lifted and body height were significant and independent determinants of LBPH, but other factors were not.

SIGNIFICANCE

The results of this study suggest that the activity of the latissimus dorsi and thoracic erector spinae muscles increases while there are no decrease in activity of the lumbar multifidus muscle and excessive extension of the lumbar spine during QULEL in young men with LBPH.

Sagittal alignment and mobility of the thoracolumbar spine are associated with radiographic progression of secondary hip osteoarthritis

OBJECTIVE

To identify predictors of radiographic progression of hip osteoarthritis (OA) over 12 months among functional hip impairments and spinal alignment and mobility.

DESIGN

Fifty female patients with secondary hip OA, excluding those with end-stage hip OA, participated in this prospective cohort study. Joint space width (JSW) of the hip was measured at baseline and 12 months later. With radiographic progression of hip OA over 12 months (>0.5 mm in JSW) as dependent variable, logistic regression analyses were performed to identify predictors for hip OA progression among functional impairments of the hip and spine with and without adjustment for age, body mass index (BMI), and minimum JSW at baseline. The independent variables were hip pain, Harris hip score (HHS), hip morphological parameters, hip passive range of motion (ROM) and muscle strength, and alignment and mobility of the thoracolumbar spine at baseline.

RESULTS

Twenty-one (42.0%) patients demonstrated radiographic progression of hip OA. Multivariable logistic regression analysis showed that larger anterior inclination of the spine in standing position (adjusted OR [95% CI], 1.37 [1.04-1.80]; P = 0.028) and less thoracolumbar spine mobility (adjusted OR [95% CI], 0.96 [0.92-0.99]; P = 0.037) at baseline were statistically significantly associated with radiographic progression of hip OA, even after adjustment for age, BMI, and minimum JSW.

CONCLUSIONS

The findings suggest that spinal alignment and mobility should be considered when assessing risk and designing preventive intervention for radiographic progression of secondary hip OA.

Regeneration of a Completely Transected Sciatic Nerve with Use of a Bioabsorbable Nerve Conduit Filled with Collagen with a 14-Year Follow-up: A Case Report

CASE

A 65-year-old man with a completely transected left sciatic nerve at the buttock received an implant with a bioabsorbable nerve conduit over a 20-mm gap. The conduit was filled with collagen to facilitate nerve regeneration. At 4 years after implantation, reinnervation potentials were detected in the muscles, and there was sensory recovery in the reinnervated areas. Thereafter, motor and sensory function recovered gradually over a 14-year period.

CONCLUSION

Mixed nerve regeneration after conduit-based reconstruction was demonstrated objectively. Although it took >4 years for motor and sensory functions to be regained, the nerve connection between the buttock and the foot was restored.

Association of low back pain with muscle stiffness and muscle mass of the lumbar back muscles, and sagittal spinal alignment in young and middle-aged medical workers

BACKGROUND

Muscle stiffness of the lumbar back muscles in low back pain (LBP) patients has not been clearly elucidated because quantitative assessment of the stiffness of individual muscles was conventionally difficult. This study aimed to examine the association of LBP with muscle stiffness assessed using ultrasonic shear wave elastography (SWE) and muscle mass of the lumbar back muscle, and spinal alignment in young and middle-aged medical workers.

METHODS

The study comprised 23 asymptomatic medical workers [control (CTR) group] and 9 medical workers with LBP (LBP group). Muscle stiffness and mass of the lumbar back muscles (lumbar erector spinae, multifidus, and quadratus lumborum) in the prone position were measured using ultrasonic SWE. Sagittal spinal alignment in the standing and prone positions was measured using a Spinal Mouse. The association with LBP was investigated by multiple logistic regression analysis with a forward selection method. The analysis was conducted using the shear elastic modulus and muscle thickness of the lumbar back muscles, and spinal alignment, age, body height, body weight, and sex as independent variables.

FINDINGS

Multiple logistic regression analysis showed that muscle stiffness of the lumbar multifidus muscle and body height were significant and independent determinants of LBP, but that muscle mass and spinal alignment were not. Muscle stiffness of the lumbar multifidus muscle in the LBP group was significantly higher than that in the CTR group.

INTERPRETATION

The results of this study suggest that LBP is associated with muscle stiffness of the lumbar multifidus muscle in young and middle-aged medical workers.

Relative mobility of the pelvis and spine during trunk axial rotation in chronic low back pain patients: A case-control study

Background

Trunk axial rotation is a risk factor for chronic low back pain (CLBP). The characteristics of rotational mobility in the pelvis and spine among CLBP patients are not fully understood.

Purpose

The purpose of this study was to examine three-dimensional kinematic changes, and to compare the differences of rotational mobility and coupled motion, in patients with and without CLBP.

Methods

Fifteen patients with CLBP and 15 age and sex matched healthy subjects participated in this study. Each subject performed trunk rotation to maximum range of motion (ROM) in a standing position. The kinematics data was collected using a three-dimensional motion analysis system. The outcomes measured were the rotational ROM and the spine/pelvis ratio (SPR) in transvers plane at both maximum and 50% rotation position. The coupled angles in sagittal and frontal planes were also measured.

Results

No significant differences in rotational ROM of the thorax, pelvis, and spine were observed between two groups at maximum rotation position. However, there was a significant interaction between groups and rotational ROM of pelvis and spine (F = 4.57, p = 0.04), and the SPR in CLBP patients was significantly greater than that of the healthy subjects (CLBP; 0.50 ± 0.10 Control; 0.41 ± 0.12, p = 0.04). The results at 50% rotation position were similar to that at maximum rotation. This indicates a relative increase in spinal rotation in the CLBP patients during trunk rotation. Moreover, the CLBP patients exhibited a significantly higher anterior tilt of the pelvis and extension of the spine in the sagittal plane coupled with rotation.

Conclusions

CLBP patients had relative hyper rotational mobility of the spine as well as excessive spinal extension coupled with trunk rotation. These results suggest that uncoordinated trunk rotation might be a functional failure associated with CLBP.

Daily cumulative hip moment is associated with radiographic progression of secondary hip osteoarthritis

OBJECTIVE

To investigate whether higher daily cumulative hip moment at baseline is associated with subsequent radiographic progression of hip osteoarthritis (OA) over 12 months.

DESIGN

Fifty patients with secondary hip OA, excluding patients with end-stage hip OA, participated in this prospective cohort study. Joint space width (JSW) of the hip was measured at baseline and 12 months later. With radiographic progression of hip OA (>0.5 mm/year in JSW) as dependent variable (yes/no), univariable and multivariable logistic regression analyses were performed to assess the association between load-related parameters during gait (i.e., peak hip moment, hip moment impulse, and daily cumulative hip moment [product of hip moment impulse and mean steps/day]) and hip OA progression with and without adjustment for age, body weight, and minimum JSW.

RESULTS

Of the 50 patients (47.4 ± 10.7 years old), 21 (42.0%) were classified into the progression group. The higher daily cumulative hip moment in the frontal plane at baseline was statistically significantly associated with radiographic progression of hip OA (adjusted odds ratio (OR) [95% confidence interval (CI)], 1.34 [1.06-1.70]; P = 0.013). The higher daily cumulative hip moment in the sagittal plane was also approaching significance in its association with hip OA progression (adjusted OR, 1.80 [0.99-3.26]; P = 0.052).

CONCLUSIONS

In the female patients with secondary hip OA, higher daily cumulative hip moment, particularly in the frontal plane, was a predictor of radiographic progression of hip OA over 12 months. Reduction in daily cumulative hip moment by modification in gait and physical activity may potentially slow hip OA progression.

Associations of radiographic degeneration and pain with daily cumulative hip loading in patients with secondary hip osteoarthritis

The purpose of this study was to investigate the associations of radiographic and clinical variables of hip osteoarthritis (OA) with alterations in gait and joint loading in patients with secondary hip OA. Fifty females with secondary hip OA were participated. The minimum joint space width (mJSW) of the hip as a degenerative sign and Sharp and center edge (CE) angles as morphological variables were measured radiographically. Hip joint pain was assessed using a visual analog scale. As gait variables, walking speed, range of hip motion, hip moment peak, and hip moment impulse were calculated. Daily cumulative hip loading was calculated as the hip moment impulse multiplied by the mean number of steps per day. After bivariate correlation analyses between dependent (mJSW and pain) and independent variables (age, body mass index, sharp/CE angles, steps per day, and gait variables), separate forward-backward stepwise multiple regression analyses were performed for each dependent variable. Daily cumulative hip loading in the sagittal plane (β = 0.30, p = 0.021) and age (β = -0.36, p = 0.007) were significantly associated with the mJSW. Walking speed (β = -0.36, p = 0.008) and age (β = 0.29, p = 0.031) were significantly associated with hip joint pain. Decrease in daily cumulative hip loading in the sagittal plane was associated with mJSW independently of age. Although the causal relationship was not clear, patients with hip OA reduced total exposure to hip joint loading adaptively rather than lowering the hip moment peak concerning worsening of hip degeneration. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1977-1983, 2016.

Radiographic and clinical factors associated with one-leg standing and gait in patients with mild-to-moderate secondary hip osteoarthritis

A decline in physical function associated with secondary hip osteoarthritis (OA) may be caused by both radiographic and clinical factors; however, the underlying mechanism remains unclear. The purpose of this study was to determine how joint degeneration, hip morphology, pain, hip range of motion (ROM), and hip muscle strength relate to one-leg standing (OLS) and gait in patients with mild-to-moderate secondary hip osteoarthritis. Fifty-five female patients (ages 22-65 years) with mild-to-moderate hip OA secondary to hip dysplasia were consecutively enrolled. Balance during OLS and three-dimensional hip angle changes while maintaining the OLS and at foot-off of the raised leg were measured. Gait speed and peak three-dimensional hip joint angles during gait were also measured. The associations between dependent variables (balance, gait speed, and hip kinematic changes) and independent variables (age, body mass index, pain, joint degeneration, hip morphologic abnormality, passive hip ROM, and hip muscle strength) were determined. While lower hip muscle strength was associated with hip kinematic changes such as flexion and internal rotation while maintaining OLS, decreased acetabular head index (AHI) and increased pain were associated with hip extension and abduction at foot-off in OLS. Decreased passive hip ROM was associated with decreased peak hip angles (extension, adduction, and external and internal rotation) during gait, although increased pain and decreased hip extension muscle strength were associated with slower gait speed. In this study of patients with secondary hip OA, AHI, pain, and hip impairments were associated with OLS and gait independently from age and radiographic degeneration.

The effect of three-dimensional postural change on shear elastic modulus of the iliotibial band

To understand and treat iliotibial band (ITB) syndrome, caused by excessive compression between the ITB and lateral femoral condyle, it is important to identify factors contributing to an increase in ITB stiffness. The purpose of this study was to clarify the factors that contribute to an increase in ITB stiffness by examining the relationship between three-dimensional postural changes and ITB stiffness. Fourteen healthy individuals performed one-leg standing under 7 conditions (including normal one-leg standing as a control condition) in which the pelvic position was changed in three planes. The shear elastic modulus in the ITB was measured using shear-wave elastography, as a measure of ITB stiffness. The three-dimensional joint angles and external joint moments in the hip and knee joints were also measured to confirm the changes in joint angles and external load. Compared to the normal one-leg standing condition, ITB stiffness was significantly increased in the pelvic posterior tilted position (i.e. hip extension), contralateral pelvic dropped position (i.e. hip adduction), and contralateral pelvic posterior rotated position (i.e. hip external rotation). The findings suggest that interventions to reduce hip extension, adduction, and external rotation might be useful if these excessive positional changes are detected in patients with ITB syndrome.

The effect of angle and moment of the hip and knee joint on iliotibial band hardness

Although several studies have described kinematic deviations such as excessive hip adduction in patients with iliotibial band (ITB) syndrome, the factors contributing to increased ITB hardness remains undetermined, owing to lack of direct in vivo measurement. The purpose of this study was to clarify the factors contributing to an increase in ITB hardness by comparing the ITB hardness between the conditions in which the angle, moment, and muscle activity of the hip and knee joint are changed. Sixteen healthy individuals performed the one-leg standing under five conditions in which the pelvic and trunk inclination were changed in the frontal plane. The shear elastic modulus in the ITB was measured as an indicator of the ITB hardness using shear wave elastography. The three-dimensional joint angle and external joint moment in the hip and knee joints, and muscle activities of the gluteus maximus, gluteus medius, tensor fasciae latae, and vastus lateralis, which anatomically connect to the ITB, were also measured. ITB hardness was significantly increased in the posture with pelvic and trunk inclination toward the contralateral side of the standing leg compared with that in all other conditions (increase of approximately 32% compared with that during normal one-leg standing). This posture increased both the hip adduction angle and external adduction moment at the hip and knee joint, although muscle activities were not increased. Our findings suggest that coexistence of an increased adduction moment at the hip and knee joints with an excessive hip adduction angle lead to an increase in ITB hardness.