An exploratory investigation of patellofemoral joint loadings during directional lunges in badminton

Effect of core strength training on the badminton player's performance: A systematic review & meta-analysis

BACKGROUND

Core strength training (CST) has been shown to improve performance in several sports disciplines. CST is recognized as one of the crucial elements that enhance athletic performance, particularly impacting badminton skills. Despite its popularity as a strength training method among badminton players, there is a lack of comprehensive studies examining the effectiveness of CST on the performance of these athletes.

OBJECTIVE

This study aims to ascertain CST's effects on badminton players' performance.

METHOD

This study followed PRISMA principles and conducted comprehensive searches in well-known academic databases (SCOPUS, Pubmed, CNKI, Web of Science, Core Collection, and EBSCOhost) up to August 2023. The inclusive criteria were established using the PICOS framework. Following their inclusion based on PICOS criteria, the selected studies underwent literature review and meta-analysis. The methodological quality of the assessments was evaluated using Cochrane Collaboration's risk of bias tools bias risk tools and recommendations for a graded assessment, development, and evaluation.

RESULTS

The analysis included participants aged 10-19 years from 13 studies of moderate quality, totaling 208 individuals. The CST intervention s lasted between 4 to 16 weeks, with a frequency of 1 to 4 sessions per week and each session lasting 20 to 120 minutes. Sample sizes across these studies ranged from 8 to 34 participants. According to the meta-analysis, CST significantly influenced badminton performance, particularly in areas of explosive power (ES = 0.03 P = 0.04), front-court skill (ES = 2.53, P = 0.003), and back-court skill (ES = 2.33, P = 0.002).

CONCLUSION

CST enhances badminton players' fitness (strength, power, balance, and stability), in situ (front/back-court) skills, and movement position hitting. However, its effects on speed, endurance, agility, flexibility, and coordination are unclear, revealing a research gap. The precise benefits of CST, especially on flexibility and specific hitting skills (smashes, clears, drives, net shots, crosscourt, push, and lift shots), need more investigation. Additionally, research on CST's impact on female athletes is significantly lacking.

Biomechanical Effects of the Badminton Split-Step on Forecourt Lunging Footwork

BACKGROUND

This research investigates the biomechanical impact of the split-step technique on forehand and backhand lunges in badminton, aiming to enhance players' on-court movement efficiency. Despite the importance of agile positioning in badminton, the specific contributions of the split-step to the biomechanical impact of lunging footwork still need to be determined.

METHODS

This study examined the lower limb kinematics and ground reaction forces of 18 male badminton players performing forehand and backhand lunges. Data were collected using the VICON motion capture system and Kistler force platforms. Variability in biomechanical characteristics was assessed using paired-sample t-tests and Statistical Parametric Mapping 1D (SPM1D).

RESULTS

The study demonstrates that the split-step technique in badminton lunges significantly affects lower limb biomechanics. During forehand lunges, the split-step increases hip abduction and rotation while decreasing knee flexion at foot contact. In backhand lunges, it increases knee rotation and decreases ankle rotation. Additionally, the split-step enhances the loading rate of the initial ground reaction force peak and narrows the time gap between the first two peaks.

CONCLUSIONS

These findings underscore the split-step's potential in optimizing lunging techniques, improving performance and reducing injury risks in badminton athletes.

Effect of anterior cruciate ligament injury on acceleration response of knee joint

This study investigated the effect of anterior cruciate ligament (ACL) injury on relative acceleration of the tibia and femur during a number of tests/activities, in order to assess the feasibility of acceleration-based diagnosis of ACL injury using inertial sensors. First, a detailed finite element model of the knee joint was developed to simulate the target tests/activities, and identify those in which a large difference between the maximum acceleration peaks (MAPs) of the healthy and ACL injured knees is likely to be observed. The promising tests/activities were entered in an experimental study, where the relative accelerations of the tibiae and femurs of 20 individuals with unilateral ACL injury, allocated randomly to two groups of conscious and unconscious test conditions, were recorded. Model predictions indicated MAP ratios>1.5 for the ACL-injured to healthy knees, during the anterior drawer, Lachman, and pivot-shift tests, as well as the lunge activity. The experimental MAP results indicated acceptable test-retest reliabilities for all tests (coefficient of variation<0.25), and significant MAP differences (p < 0.05) in the anterior drawer and pivot-shift tests, in both coconscious and unconscious conditions. The individualized MAP results indicated side-to-side differences>2 m/s2 for all subjects during unconscious pivot shift tests, and >0.5 m/s2 for eight cases out of ten during conscious anterior drawer tests. It was concluded that the pivot shift test had a great repeatability and discriminative ability for acceleration-based diagnosis of ACL injury in unconscious condition. For the conscious condition, however, the anterior drawer test was appeared to be most promising.

Influence of Torsional Stiffness in Badminton Footwear on Lower Limb Biomechanics

Torsional stiffness of athletic footwear plays a crucial role in preventing injury and improving sports performance. Yet, there is a lack of research focused on the biomechanical effect of torsional stiffness in badminton shoes. This study aimed to comprehensively investigate the influence of three different levels of torsional stiffness in badminton shoes on biomechanical characteristics, sports performance, and injury risk in badminton players. Fifteen male players, aged 22.8 ± 1.96 years, participated in the study, performing badminton-specific tasks, including forehand clear stroke [left foot (FCL) and right foot (FCR)], 45-degree sidestep cutting (45C), and consecutive vertical jumps (CVJ). The tasks were conducted wearing badminton shoes of torsional stiffness measured with Shore D hardness 50, 60, and 70 (referred to as 50D, 60D, and 70D, respectively). The primary biomechanical parameters included ankle, knee, and MTP joint kinematics, ankle and knee joint moments, peak ground reaction forces, joint range of motion (ROM), and stance time. A one-way repeated measures ANOVA was employed for normally distributed data and Friedman tests for non-normally distributed data. The 70D shoe exhibited the highest ankle dorsiflexion and lowest ankle inversion peak angles during 45C task. The 60D shoe showed significantly lower knee abduction angle and coronal motions compared to the 50D and 70D shoes. Increased torsional stiffness reduced stance time in the FCR task. No significant differences were observed in anterior-posterior and medial-lateral ground reaction forces (GRF). However, the 70D shoe demonstrated higher vertical GRF than the 50D shoe while performing the FCR task, particularly during 70% - 75% of stance. Findings from this study revealed the significant role of torsional stiffness in reducing injury risk and optimizing performance during badminton tasks, indicating that shoes with an intermediate level of stiffness (60D) could provide a beneficial balance between flexibility and stability. These findings may provide practical references in guiding future badminton shoe research and development. Further research is necessary to explore the long-term effects of altering stiffness, considering factors such as athletic levels and foot morphology, to understand of the influence of torsional stiffness on motion biomechanics and injury prevalence in badminton-specific tasks.

Model Properties and Clinical Application in the Finite Element Analysis of Knee Joint: A Review

The knee is the most complex joint in the human body, including bony structures like the femur, tibia, fibula, and patella, and soft tissues like menisci, ligaments, muscles, and tendons. Complex anatomical structures of the knee joint make it difficult to conduct precise biomechanical research and explore the mechanism of movement and injury. The finite element model (FEM), as an important engineering analysis technique, has been widely used in many fields of bioengineering research. The FEM has advantages in the biomechanical analysis of objects with complex structures. Researchers can use this technology to construct a human knee joint model and perform biomechanical analysis on it. At the same time, finite element analysis can effectively evaluate variables such as stress, strain, displacement, and rotation, helping to predict injury mechanisms and optimize surgical techniques, which make up for the shortcomings of traditional biomechanics experimental research. However, few papers introduce what material properties should be selected for each anatomic structure of knee FEM to meet different research purposes. Based on previous finite element studies of the knee joint, this paper summarizes various modeling strategies and applications, serving as a reference for constructing knee joint models and research design.

Accurately and effectively predict the ACL force: Utilizing biomechanical landing pattern before and after-fatigue

BACKGROUND AND OBJECTIVE

As a fundamental exercise technique, landing can commonly be associated with anterior cruciate ligament (ACL) injury, especially during after-fatigue single-leg landing (SL). Presently, the inability to accurately detect ACL loading makes it difficult to recognize the risk degree of ACL injury, which reduces the effectiveness of injury prevention and sports monitoring. Increased risk of ACL injury during after-fatigue SL may be related to changes in ankle motion patterns. Therefore, this study aims to develop a highly accurate and easily implemented ACL force prediction model by combining deep learning and the explored relationship between ACL force and ankle motion pattern.

METHODS

First, 56 subjects' during before and after-fatigue SL data were collected to explore the relationship between the ankle initial contact angle (AIC), ankle range of motion (AROM) and peak ACL force (PAF). Then, the musculoskeletal model was developed to simulate and calculate the ACL force. Finally, the ACL force prediction model was constructed by combining the explored relationship and sparrow search algorithm (SSA) to optimize the extreme learning machine (ELM) and long short-term memory (LSTM).

RESULTS

There was almost a stronger linear relationship between the PAF and AIC (R = -0.70), AROM (R2 = -0.61). By substituting AIC and AROM as independent variables in the SSA-ELM prediction model, the model shows excellent prediction performance because of very strong correlation (R2 = 0.9992,  MSE = 0.0023,  RMSE = 0.0474). Based on the equal scaling by combining results of SSA-ELM and SSA-LSTM, the prediction model achieves excellent performance in ACL force prediction of the overall waveform (R2 = 0.9947,  MSE = 0.0076,  RMSE = 0.0873).

CONCLUSION

By increasing the AIC and AROM during SL, the lower limb joint energy dissipation can be increased and the PAF reduced, thus reducing the impact loads on the lower limb joints and reducing ACL injuries. The proposed ACL dynamic load force prediction model has low input variable demands (sagittal joint angles), excellent generalization capabilities and superior performance in terms of high accuracy. In the future, we plan to use it as an accurate ACL injury risk assessment tool to promote and apply it to a wider range of sports training and injury monitoring.

Intelligent prediction of lower extremity loadings during badminton lunge footwork in a lab-simulated court

Introduction: Playing badminton has been reported with extensive health benefits, while main injuries were documented in the lower extremity. This study was aimed to investigate and predict the knee- and ankle-joint loadings of athletes who play badminton, with "gold standard" facilities. The axial impact acceleration from wearables would be used to predict joint moments and contact forces during sub-maximal and maximal lunge footwork. Methods: A total of 25 badminton athletes participated in this study, following a previously established protocol of motion capture and musculoskeletal modelling techniques with the integration of a wearable inertial magnetic unit (IMU). We developed a principal component analysis (PCA) statistical model to extract features in the loading parameters and a multivariate partial least square regression (PLSR) machine learning model to correlate easily collected variables, such as the stance time, approaching velocity, and peak accelerations, with knee and ankle loading parameters (moments and contact forces). Results: The key variances of joint loadings were observed from statistical principal component analysis modelling. The promising accuracy of the partial least square regression model using input parameters was observed with a prediction accuracy of 94.52%, while further sensitivity analysis found a single variable from the ankle inertial magnetic unit that could predict an acceptable range (93%) of patterns and magnitudes of the knee and ankle loadings. Conclusion: The attachment of this single inertial magnetic unit sensor could be used to record and predict loading accumulation and distribution, and placement would exhibit less influence on the motions of the lower extremity. The intelligent prediction of loading patterns and accumulation could be integrated to design training and competition schemes in badminton or other court sports in a scientific manner, thus preventing fatigue, reducing loading-accumulation-related injury, and maximizing athletic performance.

Dose-response effect of incremental lateral-wedge hardness on the lower limb Biomechanics during typical badminton footwork

Badminton footwork has been characterised with jump-landing, cross step, side side and lunges, which requires movement agility to facilitate on-court performance. A novel badminton shoe design with systematic increase of lateral wedge hardness (Asker C value of 55, 60, 65, and 70) was developed and investigated in this study, aiming to analyse the dose-response effect of incremental wedge hardness on typical badminton footwork. Stance time and joint stiffness were employed to investigate the footwork performance, and the factorial Statistical non-Parametric Mapping and Principal Component Analysis (PCA) were used to quantify the biomechanical responses over the stance. As reported, shorter contact times (decreased by 8.9%-13.5%) and increased joint stiffness (in side step) of foot-ankle complex were found, suggesting improved footwork stability and agility from increased hardness. Time-varying differences were noted during the initial landing and driving-off phase of cross and side steps and drive-off returning of lunges, suggesting facilitated footwork performance. The reconstructed modes of variations from PCA further deciphered the biomechanical response to the wedge dosage, especially during drive-off, to understand the improved footwork agility and stability.

Toward improved understanding of foot shape, foot posture, and foot biomechanics during running: A narrative review

The current narrative review has explored known associations between foot shape, foot posture, and foot conditions during running. The artificial intelligence was found to be a useful metric of foot posture but was less useful in developing and obese individuals. Care should be taken when using the foot posture index to associate pronation with injury risk, and the Achilles tendon and longitudinal arch angles are required to elucidate the risk. The statistical shape modeling (SSM) may derive learnt information from population-based inference and fill in missing data from personalized information. Bone shapes and tissue morphology have been associated with pathology, gender, age, and height and may develop rapid population-specific foot classifiers. Based on this review, future studies are suggested for 1) tracking the internal multi-segmental foot motion and mapping the biplanar 2D motion to 3D shape motion using the SSM; 2) implementing multivariate machine learning or convolutional neural network to address nonlinear correlations in foot mechanics with shape or posture; 3) standardizing wearable data for rapid prediction of instant mechanics, load accumulation, injury risks and adaptation in foot tissue and bones, and correlation with shapes; 4) analyzing dynamic shape and posture via marker-less and real-time techniques under real-life scenarios for precise evaluation of clinical foot conditions and performance-fit footwear development.

Development and Validation of a Subject-Specific Coupled Model for Foot and Sports Shoe Complex: A Pilot Computational Study

Nowadays, footwear serves an essential role in improving athletic performance and decreasing the risk of unexpected injuries in sports games. Finite element (FE) modeling is a powerful tool to reveal the biomechanical interactions between foot and footwear, and establishing a coupled foot-shoe model is the prerequisite. The purpose of this pilot study was to develop and validate a 3D FE coupled model of the foot and sports shoe complex during balanced standing. All major foot and shoe structures were constructed based on the participant’s medical CT images, and 3D gait analysis was conducted to define the loading and boundary conditions. Sensitivity analysis was applied to determine the optimum material property for shoe sole. Both the plantar and shoe sole areas were further divided into four regions for model validation, and the Bland–Altman method was used for consistency analysis between methods. The simulated peak plantar and sole pressure distribution showed good consistency with experimental pressure data, and the prediction errors were all less than 10% during balanced standing with only two exceptions (medial and lateral forefoot regions). Meanwhile, the Bland–Altman analysis demonstrated a good agreement between the two approaches. The sensitivity analysis suggested that shoe sole with Young’s modulus of 2.739 MPa presented the greatest consistency with the measured data in our scenario. The established model could be used for investing the complex biomechanical interactions between the foot and sports shoe and optimizing footwear design, after it has been fully validated in the subsequent works under different conditions.

A Pilot Study of Muscle Force between Normal Shoes and Bionic Shoes during Men Walking and Running Stance Phase Using Opensim

The original idea for bionic shoes (BSs) involves combining the function of unstable foot conditions and the structure of the human plantar. The purpose of this study was to investigate the differences between the normal shoes (NS) and the BS during the stance phases of walking and running. A total of 15 Chinese males from Ningbo University were recruited for this study (age: 24.3 ± 2.01 years; height: 176.25 ± 7.11 cm, body weight (BW): 75.75 ± 8.35 kg). The participants were asked to perform a walking and running task. Statistical parametric mapping (SPM) analysis was used to investigate any differences between NSs and BSs during the walking and running stance phases. The results demonstrated that there were significant differences found (21.23–28.24%, p = 0.040; 84.47–100%, p = 0.017) in hip extension and flexion between the NS and the BS during the walking stance phase. There were no significant differences found in ankle and moment during the running stance phase. Significant differences were found in the rectus femoris (5.29–6.21%; p = 0.047), tibialis anterior (14.37–16.40%; p = 0.038), and medial gastrocnemius (25.55–46.86%; p < 0.001) between the NS and the BS during the walking stance phase. Significant differences were found in rectus femoris (12.83–13.10%, p = 0.049; 15.89–80.19%, p < 0.001), tibialis anterior (15.85–18.31%, p = 0.039; 21.14–24.71%, p = 0.030), medial gastrocnemius (80.70–90.44%; p = 0.007), and lateral gastrocnemius (11.16–27.93%, p < 0.001; 62.20–65.63%, p = 0.032; 77.56–93.45%, p < 0.001) between the NS and the BS during the running stance phase. These findings indicate that BSs are more efficient for muscle control than unstable shoes and maybe suitable for rehabilitation training.

A Simulation Analysis of Maternal Pelvic Floor Muscle

Pelvic floor disorder (PFD) is a common disease affecting the quality of life of middle-aged and elderly women. Pelvic floor muscle (PFM) damage is related to delivery mode, fetal size, and parity. Spontaneous vaginal delivery causes especially great damage to PFM. The purpose of this study was to summarize the characteristics of PFM action during the second stage of labor by collecting female pelvic MRI (magnetic resonance imaging) data and, further, to try to investigate the potential pathogenetic mechanism of PFD. A three-dimensional model was established to study the influence factors and characteristics of PFM strength. In the second stage of labor, the mechanical responses, possible damage, and the key parts of postpartum lesions of PFM due to the different fetal biparietal diameter (BPD) sizes were analyzed by finite element simulations. The research results showed that the peak stress and strain of PFM appeared at one-half of the delivery period and at the attachment point of the pubococcygeus to the skeleton. In addition, during the simulation process, the pubococcygeus was stretched by about 1.2 times and the levator ani muscle was stretched by more than two-fold. There was also greater stress and strain in the middle area of the levator ani muscle and pubococcygeus. According to the statistics, either being too young or in old maternal age will increase the probability of postpartum PFM injury. During delivery, the entire PFM underwent the huge deformation, in which the levator ani muscle and the pubococcygeus were seriously stretched and the attachment point between the pubococcygeus and the skeleton were the places with the highest probability of postpartum lesions.

Kinematic Comparison on Lower Limb Kicking Action of Fetuses in Different Gestational Weeks: A Pilot Study

The fetal movements during different gestational weeks are essential for normal musculoskeletal development. The kinematic characteristics of fetuses with small differences in gestational weeks may be different and important. Ultrasonographic videos of fetal kicking action and plantarflexion action were collected from three healthy pregnant women (24, 27, and 30 gestational weeks) with normal fetal development. The kinematic characteristics, including angular range and angular velocity, were analyzed. These kinematic parameters were measured using simi motion. The final knee angle was found to decrease with progressive gestational weeks. Compared with 24 w, the knee joint angle at 27 w and 30 w was significantly reduced at the end of a kick-type movement (p < 0.01). Except for the mean angular velocity of the knee joint, there were no significant differences in the other conditions. The value at 30 w for mean angular velocity was significantly higher than that at 24 w (p = 0.02). In the ankle joint, no significant differences were observed between different conditions. Therefore, we can conclude that there was no significant difference in the kinematic characteristics of the ankle joint for small gestational age gaps, but there was a significant difference in the knee joint. As the gestation weeks increase, the range of kicking motion tends to decrease. The reason may be that with the increase of gestational weeks, fetal lower limb musculoskeletal development is gradually enhanced; the slower growth rate indicates that development reaches a peak level in weeks 24 to 30.