3-dimensional Motion Analysis Research Articles

AN EXPLORATION OF MOVEMENT AND HANDLING BY PHYSIOTHERAPISTS IN A REHABILITATION SETTING: A MOTION ANALYSIS STUDY

Purpose and BackgroundWork-related musculoskeletal disorders (WRMSD) can affect 56–80% of physiotherapists. Patient handling is reported as a significant risk factor for developing WRMSD with the back most frequently injured. Physiotherapists perform therapeutic handling to manually assist and facilitate patients’ movement to aid rehabilitation, which can increase physiotherapists risk of experiencing high forces during patient handling.Methods and ResultsA descriptive cross-sectional study was completed to explore and quantitatively measure the movement of ten physiotherapists during patient handling, over one working day, in a neurological setting. A wearable 3-dimensional motion analysis system, Xsens (Movella, Henderson, NV), was used to measure physiotherapist movement and postures in the ward setting during patient treatment sessions. The resulting joint angles were reported descriptively and compared against a frequently used ergonomic assessment tool, the Rapid Upper Limb Assessment (RULA).Physiotherapists adopted four main positions during patient handling tasks: 1) kneeling; 2) half-kneeling; 3) standing; and 4) sitting. Eight patient handling tasks were identified and described: 1) Lie-to-sit; 2) sit-to-lie; 3) sit-to-stand; facilitation of 4) upper limb; 5) lower limb; 6) trunk; and 7) standing treatments; and 8) walking facilitation. Kneeling and sitting positions demonstrated greater neck extension and greater lumbosacral flexion during treatments which scores highly with the RULA.ConclusionThis research identified that patient treatment tasks were more often performed in kneeling or sitting positions than standing. Current moving and handling guidance teaches moving and handling in a standing position; loading and stresses experienced by the physiotherapists may differ in sitting or kneeling positions.Conflicts of interestNoneSources of fundingNoneThis work has been presented as a poster at the CSP conference Glasgow 2023.

Influence of Lead Knee Extension on Ball Velocity and Elbow Varus Torque in Professional and High School Baseball Pitchers.

When the lead leg of a pitcher contacts the ground, the knee braces and then rapidly extends, initiating energy transfer to begin pelvis and trunk rotation. To investigate the relationship of lead knee extension during the pitching delivery with peak lead knee extension velocity, ball velocity, and elbow varus torque in high school and professional pitchers. Descriptive laboratory study. Data from 50 professional (PRO) and 50 high school (HS) pitcher groups were retrospectively analyzed. Pitchers threw 8 to 12 fastballs under 3-dimensional motion analysis (480 Hz). The groups were divided according to high or low lead knee extension: PRO-high (n = 18), PRO-low (n = 16), HS-high (n = 16), and HS-low (n = 17). Lead knee flexion, lead knee extension velocity, ball velocity, and elbow varus torque were analyzed between groups. Regression analyses were performed to quantify associations between lead knee extension and ball velocity and elbow varus torque for all pitchers. At foot contact, all pitchers landed with similar knee flexion. PRO-high and HS-high pitchers had significantly greater lead knee extension through remaining pitching time points compared with the PRO-low and HS-low pitchers. PRO-high pitchers had faster ball velocity than PRO-low pitchers (39.8 ± 1.1 vs 39.3 ± 1.3 m/s, respectively), and HS-high pitchers had faster ball velocity than HS-low pitchers (34.1 ± 2.6 vs 31.2 ± 1.8 m/s, respectively) (P < .05). PRO-high pitchers had decreased elbow varus torque compared with PRO-low pitchers (85.3 ± 10.7 vs 95.4 ± 13.3 N·m, respectively); conversely, HS-high pitchers had greater elbow varus torque than HS-low pitchers (64.2 ± 14.7 vs 56.3 ± 12.2 N·m, respectively). For every 1° increase in lead knee extension, ball velocity increased by 0.47 m/s (P < .001) and elbow varus torque increased by 0.27 N·m (P = .025). Proper lead knee extension allowed efficient energy transfer through the kinetic chain to produce optimal ball velocity and minimize elbow varus torque in professional pitchers. Conversely, while proper lead knee extension improved ball velocity among high school pitchers, this did not minimize elbow varus torque. Professional pitchers can extend their lead knee with minimal impact at the elbow. In high school pitchers, cognizance of proper full-body pitching mechanics remains a priority over increased velocity.

Postural Control During Single-Leg Landing in Female Athletes After Anterior Cruciate Ligament Reconstruction.

Secondary anterior cruciate ligament (ACL) injury is a complication of ACL reconstruction (ACLR), which may result from altered neuromuscular control affecting anticipatory postural adjustments (APAs) and compensatory postural adjustments (CPAs) required for maintaining balance during movement. However, it remains unclear how APAs and CPAs differ in single-leg landings post-ACLR compared to healthy subjects. The purpose of this study was to clarify the differences in muscle activities of APAs and CPAs, lower limb kinematics, and kinetics between athletes with a history of ACLR and healthy athletes during single-leg landing. Cross-sectional study. Eighteen female athletes were recruited and divided into ACLR (n = 9) and control groups (n = 9). The experimental task involved a single-leg landing from a 30 cm box. Joint angles and moments were determined using a 3-dimensional motion analysis system, while muscle activity was assessed using surface electromyography. Analysis intervals were divided into two phases: the APA phase (-150 ms to 50 ms) and the CPA phase (50 ms to 250 ms), with initial contact (0 ms) as the reference point. Muscle activity onset time was defined as the time when the baseline exceeded by the sum of mean values and 2 standard deviations. No significant differences were observed in muscle activity or onset time between the ACLR and control groups. However, an increased hip external rotation moment was observed during the CPA phase in the ACLR group. These findings suggest that APAs and CPAs of athletes who returned to sports more than 1 year post-ACLR may be similar. The increased hip external rotation moment in the ACLR group during the CPA phase could represent a specific compensatory strategy to decrease the hip internal rotation angle post-ACLR. III.

Anterior-Posterior Center of Pressure Is Associated With Knee Extensor Moment During Landing After Anterior Cruciate Ligament Reconstruction.

A reduced knee extensor moment (KEM) in the involved limb and asymmetry in the KEM during landing tasks are observed after anterior cruciate ligament reconstruction (ACLR). There is limited information about the association of kinetic and kinematic parameters with the KEM during landing after ACLR. This study investigated the association of the anterior-posterior center of pressure (AP-COP) position, vertical ground reaction force (VGRF), and lower limb joint angles with the KEM during landing in female athletes following ACLR. Cross-sectional study. Twenty-two female athletes who underwent ACLR performed a drop vertical jump at 7.9 (1.7)months after surgery. We evaluated the KEM, AP-COP position, VGRF, and sagittal plane hip, knee, and ankle angles using a 3-dimensional motion analysis system with force plates. The peak KEM in the involved limb was significantly smaller than that in the uninvolved limb during landing (1.43 [0.33]N·m/kg/m vs 1.84 [0.41]Nm/kg/m, P = .001). The VGRF in the involved limb was significantly smaller than that in the uninvolved limb (11.9 [2.3]N/kg vs 14.6 [3.5]N/kg, P = .005). The limb symmetry index of the KEM was predicted by that of the VGRF (P < .001, R2 = .621, β = 0.800). The KEM was predicted by the AP-COP position in the involved limb (P = .015, R2 = .227, β = 0.513) and by the VGRF in the uninvolved limb (P = .018, R2 = .213, β = 0.500). No significant correlation was noted between the KEM and the lower limb joint angles. The AP-COP position and VGRF were associated with the KEM during landing. Evaluating the VGRF and AP-COP position, not the lower limb joint angles, may contribute to understanding the KEM during double-leg landing after ACLR in the clinical setting.

Identifying Risk Factors for Preexisting or Developing Low Back Pain in Youth, High School, and Collegiate Lacrosse Players Using 3-Dimensional Motion Analysis.

Low back pain (LBP) is a common condition that can affect athletes of all ages. The risk factors for LBP onset and worsening associated with the lacrosse shooting motion are not yet known. To identify training and biomechanical factors associated with preexisting LBP and development of LBP over 6 months in youth, high school, and collegiate lacrosse players. Case-control study; Level of evidence, 3. A total of 128 lacrosse players were enrolled in this study between January 2016 and January 2019. Player characteristics, lacrosse experience, and participation in other sports were self-reported. At baseline and 2-, 4-, and 6-month follow-ups, the players self-rated the presence and severity of LBP using a numeric pain rating scale (0-10 points). Participants were grouped according to LBP symptoms: no LBP at any time point (n = 102), preexisting LBP (n = 17), or developed LBP within the 6-month period (n = 9). The lacrosse shooting motion was captured via 3-dimensional motion analysis, and kinematic and kinetic variables were recorded. A Low Back Stress Index was used to estimate lumbar stress as a function of pelvic acceleration at the time of maximum lateral trunk lean during the shot. Univariate analyses of covariance and logistic regression models were used to address study aims. Compared with the no-LBP group, the preexisting LBP group demonstrated 13.9% to 22.9% lower maximum angular velocities at the pelvis, trunk, and shoulders in the transverse plane (P < .05), 19.3% less collective pelvis-shoulder rotation in the transverse plane (P = .015), and 4.5% more knee flexion excursion (P = .063). The developed-LBP group produced 2.3% to 11.1% higher angular velocities in the pelvis, trunk, and shoulder and generated maximum pelvic acceleration values 36% to 42% higher than the remaining groups (P < .05 for both). Mean Low Back Stress Index values were not statistically significant among the groups (no LBP: 12,504 ± 13,076 deg2/s2; preexisting LBP: 8808 ± 10,174 deg2/s2; developed LBP: 19,389 ± 13,590 deg2/s2; P = .157). Preexisting LBP was associated with significantly restricted motion of the pelvis, trunk, and shoulders during a lacrosse shot. Excessive pelvic acceleration may be related to the development of LBP in lacrosse players.

A method for selecting the optimal warping path of dynamic time warping in gait analysis.

This study aims to demonstrate that when performing dynamic time warping (DTW) on gait data, multiple optimal warping paths (OWPs) with a minimum sum of local costs can occur and to propose an additional OWP selection method to address this problem. A 3-dimensional motion analysis experiment was conducted on 55 adult participants, including both males and females, to acquire gait data. This study analyzed 990 instances of DTW on gait data to examine the occurrence of multiple OWPs with the minimum sum of local costs. We subsequently applied an additional selection method to the multiple OWPs to determine the feasibility of identifying a single OWP. Multiple OWPs through DTW were observed 82 times, accounting for 8.28%. Notably, on the ankle joint of males, the rate was the highest at 11.11%. Cases with two multiple OWPs were the most prevalent at 56.10%, and cases with ten or more multiple OWPs accounted for 19.51%. The additional selection method proposed in this study was applied to the 82 instances in which multiple OWPs occurred. The results demonstrated the ability to identify a unique OWP in all cases. These results hold significance in identifying the shortcomings of conventional OWP selection methods previously employed and proposing solutions. It enhances the reliability, validity, and accuracy of studies utilizing DTW.

Relationship Between Supporting Leg Stiffness and Trunk Kinematics of the Kicking Leg During Soccer Kicking.

The stiffness of the supporting leg may alter the energy transfer to the trunk and lower extremities of the kicking leg, which may affect kick performance. This study aimed to clarify whether the stiffness of the supporting leg affects the trunk kinematics during kicking and kicking performance in soccer players. Twenty-two male collegiate soccer players participated in the study. The data for the stiffness properties of the supporting leg and trunk kinematics were obtained and calculated using a 3-dimensional motion analysis system. The results showed that a greater leg stiffness of the supporting leg was associated with a lower trunk rotation angle during kicking. There were no significant correlations between the maximum swing speed and the stiffness of the supporting leg (P < .05). These results suggest that stiffness of the supporting leg may restrain trunk rotation during the kicking motion. However, the lack of a relationship with swing speed indicates the need for further investigation into its effects on kicking performance.

Evaluation of the Anterior Cruciate Ligament Injury Risk During a Jump-Landing Task Using 3-Dimensional Kinematic Analysis Versus the Landing Error Scoring System.

The Landing Error Scoring System (LESS) has been utilized on the field or in the clinic to identify patients with an increased risk for anterior cruciate ligament (ACL) injuries; however, its validity and efficacy have not been fully confirmed. To assess the efficacy of the LESS in identifying the ACL injury risk by examining the correlation between the LESS score and motion patterns on 3-dimensional kinematic analysis. Controlled laboratory study. The jump-landing motion was analyzed for 16 female basketball or badminton players who volunteered to participate in the study. All study participants were aged 19 or 20 years. The sequence of motion was evaluated with the LESS, while kinematic data were simultaneously acquired with a 3-dimensional motion analysis system utilizing the point cluster method. The correlation between the LESS score and knee kinematics was statistically analyzed. When a LESS score ≥6 was defined to be a risk factor for ACL injuries, 7 of the 16 participants (43.8%) were found to exhibit risky motion patterns. Significant correlations were noted between the LESS score and knee valgus (r = 0.87; P < .0001) and internal tibial rotation (r = 0.57; P = .02) at landing. By contrast, a substantial variability was present in knee flexion, showing no correlation with the LESS score. Significant correlations were found between the LESS score and knee valgus and internal tibial rotation during a jump-landing task. The LESS can be regarded as an effective measure to identify risky motion patterns that may increase the likelihood of ACL injuries.

Scapular dyskinesis after treatment of proximal humerus fracture, a 3-dimensional motion analysis and clinical outcomes.

The alteration of scapular kinematics can predispose patients to shoulder pathologies and dysfunction. Previous literature has associated various types of shoulder injuries with scapular dyskinesis, but there are limited studies regarding the effect that proximal humeral fractures (PHFs) have on scapular dyskinesis. This study aims to determine the change in scapulohumeral rhythm following treatment of a proximal humerus fracture as well as differences in shoulder motion and functional outcomes among patients who presented with or without scapular dyskinesis. We hypothesized that differences in scapular kinematics would be present following treatment of a proximal humerus fracture, and patients who presented with scapular dyskinesis would subsequently have inferior functional outcome scores. Patients treated for a proximal humerus fracture from May 2018 to March 2021 were recruited for this study. The scapulohumeral rhythm and global shoulder motion were determined using a 3-dimensional motion analysis (3DMA) and the scapular dyskinesis test. Functional outcomes were then compared among patients with or without scapular dyskinesis, including the SICK (scapular malposition, inferomedial border prominence, coracoid pain and malposition, and dyskinesis of scapular movement) Scapula Rating Scale, the American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES), the visual analog scale (VAS) for pain, and the EuroQol-5 Dimension 5-Level questionnaire (EQ-5D-5L). Twenty patients were included in this study with a mean age of 62.9±11.8 years and follow-up time of 1.8±0.2 years. Surgical fixation was performed in 9 of the patients (45%). Scapular dyskinesis was present in 50% of patients (n=10). There was a significant increase in scapular protraction on the affected side of patients with scapular dyskinesis during abduction of the shoulder (P=.037). Additionally, patients with scapular dyskinesis demonstrated worse SICK scapula scores (2.4±0.5 vs. 1.0±0.4, P=.024) compared to those without scapular dyskinesis. The other functional outcome scores (ASES, VAS pain scores, and EQ-5D-5L) showed no significant differences among the 2 groups (P=.848, .713, and .268, respectively). Scapular dyskinesis affects a significant number of patients following treatment of their PHFs. Patients presenting with scapular dyskinesis exhibit inferior SICK scapula scores and have more scapular protraction during shoulder abduction compared to patients without scapular dyskinesis.

Australia and New Zealand Clinical Motion Analysis Group (ANZ-CMAG) clinical practice recommendations

Clinical motion analysis involves quantitative measurement of gait patterns to identify gait anomalies that currently or have the potential to impact function, activities of daily living and participation. Clinical motion analysis services are equipped with motion capture technology and comprise specialised staff who deliver 3-dimensional motion analysis services to children and adults who present with varying levels of gait impairment. Data is then used to inform intervention recommendations to clinicians with a view to maintaining independent, functional and pain free walking (or appropriate mobility).The ANZ-CMAG (established in 2013) identified a need to establish recommendations to assist in standardising practice guidelines for both current and new clinical motion analysis services within the region. The group serves to promote collaboration between services in quality assurance processes, clinical practices, data sets and research activities. The clinical practice recommendations described in this paper cover: i) requirements for a motion analysis service (including staffing, facilities and equipment), ii) patient assessments (requirements, clinical information and data gathered, reporting and interpretation of patient data), iii) quality assurance processes (including motion capture system / biomechanical models & limitations, marker placement, data storage / record keeping, creation of normative dataset); iv) helpful resources.Better outcomes for children and adults with gait deviations is dependent upon accurate measurement and evaluation of walking and requires input from multidisciplinary clinical teams with specialist knowledge and skills. The ANZ-CMAG hopes these clinical practice recommendations are beneficial to motion analysis services with an aim to improve clinical practices, patient outcomes, and support research collaboration.

Standing Pelvic Tilt Is Associated With Dynamic Pelvic Tilt During Running When Measured by 3-Dimensional Motion Capture.

Standing pelvic tilt (PT) is related to biomechanics linked with increased risk of injury such as dynamic knee valgus. However, there is limited evidence on how standing PT relates to dynamic PT and whether the palpation meter (PALM), a tool to measure standing PT, is valid against 3-dimensional (3D) motion analysis. The purposes of this study were to (1)determine the criterion validity of the PALM for measuring standing PT and (2)identify the relationship between standing PT and dynamic PT during running. Participants (n = 25; 10 males and 15 females) had their standing PT measured by the PALM and 3D motion analysis. Dynamic PT variables were defined at initial contact and toe off. No relationship between the 2 tools was found. Significant large positive relationships between standing PT and PT at initial contact (r = .751, N = 25, P < .001) and PT at toe off (r = .761, N = 25, P < .001) were found. Since no relationship was found between standing PT measured by the PALM and 3D motion analysis, the PALM is not a valid alternative to 3D motion analysis. Clinicians may be able to measure standing PT and gain valuable information on dynamic PT, allowing clinicians to quickly assess whether further biomechanical testing is needed.

Subsequent Jumping Increases the Knee and Hip Abduction Moment, Trunk Lateral Tilt, and Trunk Rotation Motion During Single-Leg Landing in Female Individuals.

Single-leg landings with or without subsequent jumping are frequently used to evaluate landing biomechanics. The purpose of this study was to investigate the effects of subsequent jumping on the external knee abduction moment and trunk and hip biomechanics during single-leg landing. Thirty young adult female participants performed a single-leg drop vertical jumping (SDVJ; landing with subsequent jumping) and single-leg drop landing (SDL; landing without subsequent jumping). Trunk, hip, and knee biomechanics were evaluated using a 3-dimensional motion analysis system. The peak knee abduction moment was significantly larger during SDVJ than during SDL (SDVJ 0.08 [0.10]N·m·kg-1·m-1, SDL 0.05 [0.10]N·m·kg-1·m-1, P = .002). The trunk lateral tilt and rotation angles toward the support-leg side and external hip abduction moment were significantly larger during SDVJ than during SDL (P < .05). The difference in the peak hip abduction moment between SDVJ and SDL predicted the difference in the peak knee abduction moment (P = .003, R2 = .252). Landing tasks with subsequent jumping would have advantages for evaluating trunk and hip control as well as knee abduction moment. In particular, evaluating hip abduction moment may be important because of its association with the knee abduction moment.

Single leg squat test as a clinical tool to predict lower extremity injuries in adolescent athletes

Background: The single leg squat test (SLS) is a biomechanical evaluation, simple and easily performed, and has been validated against the gold standard of 3-Dimensional (D) motion analysis [1-3]. A positive SLS test used in frontal plane biomechanical analysis can indicate poor lower extremity mechanics, reduced core strength, or hip abductor weakness indicating a higher risk for lower extremity injury [4-8]. SLS test has been studied primarily with biomechanical outcomes, and there is limited injury data to assess its predictive value in adolescents. Objective: To determine the predictive value of SLS test in predicting lower extremity injuries in adolescent, high school athletes with prospective injury data collected by athletic trainers over a one year period. Design: Longitudinal, non-randomized prospective design. Setting: Clinical and field based. Interventions: 258 adolescent athletes from Central Oregon were evaluated while performing a SLS test during initial practices or during pre-participation physicals before the start of the academic year. Injuries sustained while playing sports during the following academic year were reported to each respective high school’s certified athletic trainer and recorded on the Sportsware database. Main Outcome Measurements: SLS Test and Injury Reports. Results: The sensitivity, specificity, and negative predictive value (NPV) of the SLS test in predicting lower extremity injuries were 66.67%, 36.59% and 95.74%, respectively. The sensitivity, specificity, and NPV of the SLS test in predicting a lower extremity injury in a high risk group of female soccer players were 50.00%, 30.16%, and 90.48%, respectively. Conclusion: Negative SLS in 36% of athletes was consistent with a low risk of lower extremity injury with 96% NPV. The high NPV is likely related to the low prevalence of LE injury in this study population and wouldn’t translate to higher prevalence LE injury populations. Further study is needed to determine clinical utility of the SLS test.

Interlimb Asymmetry in Knee Extension Moment During Double-Leg Squatting Is Associated With Persistent Quadriceps Weakness After ACL Reconstruction

Background: Although double-leg squatting is less dynamic and places less demand on the quadriceps compared with landing tasks, the relationship between double-leg squatting biomechanics and persistent quadriceps weakness after anterior cruciate ligament reconstruction (ACLR) is unknown. Purpose: To clarify the relationships between asymmetries in quadriceps strength and lower limb biomechanics during double-leg squatting &gt;1 year after ACLR. Study Design: Controlled laboratory study. Methods: A total of 26 participants (5.5 ± 3.8 years after ACLR) were enrolled. The limb symmetry index (LSI) of isokinetic quadriceps strength was used to divide participants into the high-quadriceps (HQ) group (LSI ≥90%; n = 18) and the low-quadriceps (LQ) group (LSI &lt;90%; n = 8). The knee, hip, and ankle extension moment (relative to body weight and support moment [sum of knee, hip, and ankle moments]) and vertical ground-reaction force during double-leg squatting were analyzed using 3-dimensional motion analysis. The association of quadriceps strength and biomechanical variables was tested using 2-way analysis of variance and univariate regression analysis. Results: A significant group-by-limb interaction was found for the peak knee extension moment and the ratios of knee and hip extension moment to support moment ( P &lt; .001, P = .015 and P &lt; .001, respectively). The LQ group showed a significantly smaller peak knee extension moment and knee to support moment ratio but a larger hip to support moment ratio in the involved limb than in the uninvolved limb (95% CIs: knee extension moment, −0.273 to −0.088 N·m/kg; knee to support moment ratio, −10.7% to −2.2%; hip to support moment ratio, 3.2% to 8.5%). No interlimb difference was found for the HQ group. The LSI of quadriceps strength was significantly associated with the LSI of peak knee extension moment ( R 2 = 0.183), knee to support moment ratio ( R 2 = 0.256), and hip to support moment ratio ( R 2 = 0.233). The mean maximum isokinetic quadriceps strength and peak knee extension moment during squatting on the involved limb of the LQ group were 2.40 ± 0.39 and 0.90 ± 0.16 N·m/kg, respectively. Conclusion: Asymmetrical biomechanics during double-leg squatting was associated with persistent quadriceps weakness after ACLR. The LQ group had reduced knee extensor moment on the involved side during squatting despite loading at approximately half the maximum strength. Clinical Relevance: Quadriceps strengthening exercises, together with interventions to improve neuromuscular control, may reduce asymmetrical biomechanics during double-leg squatting.

Biomechanical Comparison of Two Surgical Repair Techniques of the Distal Biceps Tendon

This study aimed to characterize the relationship between the distal biceps tendon force and the supination and flexion rotations during the initiation phase and to compare the functional efficiency of anatomic versus nonanatomic repairs. Seven matched pairs of fresh-frozen cadaver arms were dissected to expose the humerus and elbow while preserving the biceps brachii, elbow joint capsule, and distal radioulnar soft tissue complex. For each pair, the distal biceps tendon was severed with a scalpel and then repaired with bone tunnels placed at either the anterior (anatomic) or the posterior (nonanatomic) aspect of the bicipital tuberosity on the proximal radius. A supination test with 90° of elbow flexion and an unconstrained flexion test were conducted on a customized loading frame. The biceps tension was applied incrementally at 200 g per step, whereas the radius rotation was tracked with a 3-dimensional motion analysis system. The tendon force needed to produce a degree of supination or flexion was derived as the regression slope of the tendon force-radial rotation plots. A two-tailed paired t test was performed to compare the difference between the anatomic repair and the nonanatomic repair cadavers. Significantly greater tendon force was required to initiate the first 10° of supination with the elbow in flexion for the nonanatomic group compared with the anatomic group (1.04 ± 0.44 N/degree vs 0.68 ± 0.17 N/degree, P= .02). The average nonanatomic to anatomic ratio was 149% ± 38%. No difference existed between the two groups in the mean tendon force needed to produce the degree of flexion. Our results show that anatomic repair is more efficient in producing supination than nonanatomic repair, but only when the elbow is in 90° of flexion. When the elbow joint is not constrained, the nonanatomic supination efficiency improved, and the difference between the techniques was not significant. The present study added to the body of evidence in comparing anatomic versus nonanatomic repair of the distal biceps tendon and serves as a foundation for future biomechanical and clinical studies in this topic. Given no difference when the elbow joint was not constrained, one could argue that surgeon comfort and preference could guide which technique to use when addressing the distal biceps tendon tears. More studies will be needed to clearly define whether there will be a clinical difference between the two techniques.

Joint Coordination and Muscle-Tendon Interaction Differ Depending on The Level of Jumping Performance.

The countermovement jump is a popular measurement modality to evaluate muscle power in sports and exercise. Muscle power is essential to achieve a high jump, yet the well-coordinated movement of the body segments, which optimizes the stretch-shortening cycle (SSC) effects, is also required. Among the proposed explanations of SSC effects, this study investigated whether the ankle joint kinematics, kinetics, and muscle-tendon interaction depend on the level of jump skill and the jump task. Sixteen healthy males were grouped as a function of their jump height (High jumpers; greater than 50 cm, Low jumpers; less than 50 cm). They were instructed to jump with two intensities; light effort (20 % of their height) and maximal effort. Joint kinematics and kinetics of the lower limbs were analyzed using a 3-dimensional motion analysis system. The muscle-tendon interaction was investigated using B-mode real-time ultrasonography. As the jump intensity increased, all participants jumped with increased joint velocity and power. However, the high jumper shows less fascicle shortening velocity (-0.2 ± 0.1 m/s) than the low jumper group (-0.3 ± 0.1 m/s) and greater tendon velocity, which indicated the capability of elastic energy recoil. In addition, the delayed onset time of ankle extension in the high jumper implies better use of the catapult mechanism. The findings of this study showed that the muscle-tendon interaction differs depending on the jump skill level, suggesting a more efficient neuromuscular control in skilled jumpers.

Determining the optimal gait modification strategy for patients with knee osteoarthritis: Trunk lean or medial thrust?

BackgroundThe gait modification strategies Trunk Lean and Medial Thrust have been shown to reduce the external knee adduction moment (EKAM) in patients with knee osteoarthritis which could contribute to reduced progression of the disease. Which strategy is most optimal differs between individuals, but the underlying mechanism that causes this remains unknown. Research questionWhich gait parameters determine the optimal gait modification strategy for individual patients with knee osteoarthritis? MethodsForty-seven participants with symptomatic medial knee osteoarthritis underwent 3-dimensional motion analysis during comfortable gait and with two gait modification strategies: Medial Thrust and Trunk Lean. Kinematic and kinetic variables were calculated. Participants were then categorized into one of the two subgroups, based on the modification strategy that reduced the EKAM the most for them. Multiple logistic regression analysis with backward elimination was used to investigate the predictive nature of dynamic parameters obtained during comfortable walking on the optimal modification gait strategy. ResultsFor 68.1 % of the participants, Trunk Lean was the optimal strategy in reducing the EKAM. Baseline characteristics, kinematics and kinetics did not differ significantly between subgroups during comfortable walking. Changes to frontal trunk and tibia angles correlated significantly with EKAM reduction during the Trunk Lean and Medial Thrust strategies, respectively. Regression analysis showed that MT is likely optimal when the frontal tibia angle range of motion and peak knee flexion angle in early stance during comfortable walking are high (R2Nagelkerke = 0.12). SignificanceOur regression model based solely on kinematic parameters from comfortable walking contained characteristics of the frontal tibia angle and knee flexion angle. As the model explains only 12.3 % of variance, clinical application does not seem feasible. Direct assessment of kinetics seems to be the most optimal strategy for selecting the most optimal gait modification strategy for individual patients with knee osteoarthritis.

Normalization and possibility of classification analysis using the optimal warping paths of dynamic time warping in gait analysis.

The purpose of this study was to verify classification performance and the difference analysis between gender using optimal warping paths of dynamic time warping (DTW) and to examine the usefulness of root mean square error (RMSE) represented by the perpendicular distance from the optimal warping path to the diagonal. A 3-dimensional motion analysis experiment was performed with 24 healthy adults (male=12, female=12) in their 20s of age without gait-related diseases or injuries for the past 6 months to collect gait data. This study performed a DTW 132 times in total (male=62, female=62) for the flexion angle of the right leg's hip, knee, and ankle joints. Then, the global cost and the RMSE of the optimal warping paths were calculated and normalized. The difference analysis was performed by independent t-test. Machine learning was performed to test the classification performance using the neural network, support vector machine, and logistic regression model among the supervised models. Results analyzed using global cost and RMSE for hip, knee, and ankle joints showed a statistically significant difference between genders in global cost and RMSE for hip and knee joints but not for ankle joints using RMSE. Considering both area under the receiver operating characteristic curve and F1-score, the logistic regression model has been evaluated as the most suitable for gender classification using the global cost or RMSE. This study demonstrated that optimal warping paths could be used for statistical difference analysis and classification analysis.

A Multidimensional Assessment of a Novel Adaptive Versus Traditional Passive Ankle Sprain Protection Systems

Background: Ankle braces aim to reduce lateral ankle sprains. Next to protection, factors influencing user compliance, such as sports performance, motion restriction, and users’ perceptions, are relevant for user compliance and thus injury prevention. Novel adaptive protection systems claim to change their mechanical behavior based on the intensity of motion (eg, the inversion velocity), unlike traditional passive concepts of ankle bracing. Purpose: To compare the performance of a novel adaptive brace with 2 passive ankle braces while considering protection, sports performance, freedom of motion, and subjective perception. Study Design: Controlled laboratory study. Methods: The authors analyzed 1 adaptive and 2 passive (one lace-up and one rigid brace) ankle braces, worn in a low-cut, indoor sports shoe, which was also the no-brace reference condition. We performed material testing using an artificial ankle joint system at high and low inversion velocities. Further, 20 male, young, healthy team sports athletes were analyzed using 3-dimensional motion analysis in sports-related movements to address protection, sports performance, and active range of motion dimensions. Participants rated subjective comfort, stability, and restriction experienced when using the products. Results: Subjective stability rating was not different between the adaptive and passive systems. The rigid brace was superior in restricting peak inversion during the biomechanical testing compared with the passive braces. However, in the material test, the adaptive brace increased its stiffness by approximately 400% during the fast compared with the slow inversion velocities, demonstrating its adaptive behavior and similar stiffness values to passive braces. We identified minor differences in sports performance tasks. The adaptive brace improved active ankle range of motion and subjective comfort and restriction ratings. Conclusion: The adaptive brace offered similar protective effects in high-velocity inversion situations to those of the passive braces while improving range of motion, comfort, and restriction rating during noninjurious motions. Clinical Relevance: Protection systems are only effective when used. Compared with traditional passive ankle brace technologies, the novel adaptive brace might increase user compliance by improving comfort and freedom of movement while offering similar protection in injurious situations.

Pelvic Rotation Is Associated With Asymmetry in the Knee Extensor Moment During Double-Leg Squatting After Anterior Cruciate Ligament Reconstruction.

Asymmetry in knee extensor moment during double-leg squatting was observed after anterior cruciate ligament reconstruction, even after the completion of the rehabilitation program for return to sports. The purpose of this study was to clarify the association between asymmetry in the knee extensor moment and pelvic rotation angle during double-leg squatting after anterior cruciate ligament reconstruction. Twenty-four participants performed double-leg squatting. Kinetics and kinematics during squatting were analyzed using a 3-dimensional motion analysis system with 2 force plates. The limb symmetry index of knee extensor moment was predicted by the pelvic rotation angle (R2 = .376, P = .001). In addition, the pelvic rotation and the limb symmetry index of the vertical ground reaction force independently explained the limb symmetry index of the knee extensor moment (R2 = .635, P < .001, β of pelvic rotation = -0.489, β of vertical ground reaction force = 0.524). Pelvic rotation toward the involved limb was associated with a smaller knee extensor moment in the involved limb than in the uninvolved limb. The assessment of pelvic rotation would be useful for partially predicting asymmetry in the knee extensor moment during double-leg squatting. Minimizing pelvic rotation may improve the asymmetry in the knee extensor moment during double-leg squatting after anterior cruciate ligament reconstruction.