Backward jump-landing during sports performance will result in dynamic postural instability with a greater risk of injury, and most research studies have focused on forward landing. Differences in kinematic temporal characteristics between single-leg and double-leg backward jump-landing are seldom researched and understood. The purpose of this study was to compare and analyze lower extremity kinematic differences throughout the landing phases of forward and backward jumping using single-leg and double-leg landings (FS and BS, FD and BD). Kinematic data were collected during the landing phases of FS and BS, FD and BD in 45 participants. Through statistical parametric mapping (SPM) analysis, we found that the BS showed smaller hip and knee flexion and greater vertical ground reactive force (VGRF) than the FS during 0–37.42% (p = 0.031), 16.07–32.11% (p = 0.045), and 23.03–17.32% (p = 0.041) landing phases. The BD showed smaller hip and knee flexion than the FD during 0–20.66% (p = 0.047) and 0–100% (p < 0.001) landing phases. Most differences appeared within a time frame during the landing phase at 30–50 ms in which non-contact anterior cruciate ligament (ACL) injuries are thought to occur and are consistent with the identification of risk in biomechanical analysis. A landing strategy that consciously increases the knee and hip flexion angles during backward landing should be considered for people as a measure to avoid injury during the performance of this type of physical activity.

Background: Barbell squats are commonly used in daily training and rehabilitation. Injuries are not common when the posture is standard, but the wrong posture can lead to injuries. Rearfoot valgus is a common foot abnormality that may increase the risk of injury during sports. The purpose of this study was to compare the biomechanics of lower limbs in normal foot and valgus patients during barbell squat.Methods: In this study, 10 participants with normal foot shape and 10 participants with rearfoot valgus were enrolled. The joint angle, joint moment, and range of motion of hip, knee, and ankle joints were collected under 0, 30, and 70% one-repetition maximum (RM) load, where discrete data are statistically analyzed using the independent sample t-test, and continuous data are statistically analyzed using one-dimensional parameter statistical mapping.Results: In barbell squats, the range of motion and the joint moment of the hip, knee, and ankle in the rearfoot valgus participants were significantly larger than those in normal foot participants (p < 0.05). The participants with rearfoot valgus had a more significant knee valgus angle when squatting to the deepest (p < 0.05). In addition, with the increase in load, the participants with rearfoot valgus showed greater standardized medial knee contact force (p < 0.05). In the process of barbell squats, the participants with rearfoot valgus showed no significant difference in the foot valgus angle when compared with the normal foot shape (p > 0.05).Conclusions: The valgus population showed a greater range of joint motion when performing barbell squats and showed genu valgus and greater medial knee contact force, which may increase the risk of musculoskeletal and soft tissue damage such as meniscus wear. In addition, there was no significant difference in the rearfoot valgus angle between people with rearfoot valgus and people with normal foot shape during squatting, so barbell squatting may correct valgus to a certain extent.

Tibial shock attenuation is part of the mechanism that maintains human body stabilization during running. It is crucial to understand how shock characteristics transfer from the distal to proximal joint in the lower limb. This study aims to investigate the shock acceleration and attenuation among maximalist shoes (MAXs), minimalist shoes (MINs), and conventional running shoes (CONs) in time and frequency domains. Time-domain parameters included time to peak acceleration and peak resultant acceleration, and frequency-domain parameters contained lower (3–8 Hz) and higher (9–20 Hz) frequency power spectral density (PSD) and shock attenuation. Compared with CON and MAX conditions, MINs significantly increased the peak impact acceleration of the distal tibia (p = 0.01 and p < 0.01). Shock attenuation in the lower frequency depicted no difference but was greater in the MAXs in the higher frequency compared with the MIN condition (p < 0.01). MINs did not affect the tibial shock in both time and frequency domains at the proximal tibia. These findings may provide tibial shock information for choosing running shoes and preventing tibial stress injuries.

Objective: To evaluate the optimal choice of traditional Chinese exercise (TCE) for improving bone mineral density in postmenopausal women through a network meta-analysis.Methods: The Chinese and English databases were searched, including China National Knowledge Infrastructure, Chongqing VIP, PubMed, Web of Science and Cochrane Library. The outcomes included BMD of lumbar L2-L4, femoral neck, ward triangle, and greater trochanter. Standardized mean differences (SMD) and 95% confidence intervals (CI) were used to assess the correlation between each group of interventions, and surface under the cumulative ranking (SUCRA) was used to rank the best interventions.Results: A total of 20 randomized controlled trials (RCTs) including 1933 subjects and six interventions: [Tai Chi (TC), Baduanjin (BDJ), Wuqinxi (WQX), Yijinjing (YJJ), TA (Tai chi plus calcium supplementation), BA (Baduanjin plus calcium supplementation)] and three control measures: [Calcium supplementation (CA), Aerobic exercise (AE), Not exercise intervention (NEI)] were analyzed. Regarding BMD of lumbar L2-L4: TC [SMD = 0.99 (0.62, 1.37)], BDJ [SMD = 2.12 (1.39, 2.85)], TA [SMD = 1.12(0.17, 2.07)], BA [SMD = 2.24 (1.16, 3.31)] were superior in increasing BMD of lumbar L2-L4 relative to NEI. Regarding BMD of femoral neck: TC [SMD = 1.24 (0.70, 1.78)], BA [SMD = 3.77 (1.98, 5.56)] were superior in increasing BMD of femoral neck relative to NEI. Regarding BMD of ward’s triangle: TC [SMD = 1.63 (1.09, 2.17)] was superior in increasing BMD of ward’s triangle relative to NEI. Regarding BMD of greater trochanter: TC [SMD = 0.98 (0.28, 1.68)] were superior in increasing BMD of greater trochanter relative to NEI. TC topped the SUCRA with BMD of lumbar L2-L4: 53.8, femoral neck: 74.9, ward’s triangle: 86.9 and greater trochanter: 77.7.Conclusion: Four TCE (TC, BDJ, TA and BA) are all effective in partially improving BMD indicators in postmenopausal women, while TC was effective on all four BMD indicators, which seems to be recommended as the most suitable exercise modality for postmenopausal women.Systematic review registration: This research follows the PRISMA Network statement. The protocol for this study has been registered in the International Prospective Registry of Systematic Reviews (PROSPERO). CRD42023414944.

The football team training algorithm (FTTA) is a new metaheuristic algorithm that was proposed in 2024. The FTTA has better performance but faces challenges such as poor convergence accuracy and ease of falling into local optimality due to limitations such as referring too much to the optimal individual for updating and insufficient perturbation of the optimal agent. To address these concerns, this paper presents an improved football team training algorithm called IFTTA. To enhance the exploration ability in the collective training phase, this paper proposes the fitness distance-balanced collective training strategy. This enables the players to train more rationally in the collective training phase and balances the exploration and exploitation capabilities of the algorithm. To further perturb the optimal agent in FTTA, a non-monopoly extra training strategy is designed to enhance the ability to get rid of the local optimum. In addition, a population restart strategy is then designed to boost the convergence accuracy and population diversity of the algorithm. In this paper, we validate the performance of IFTTA and FTTA as well as six comparison algorithms in CEC2017 test suites. The experimental results show that IFTTA has strong optimization performance. Moreover, several engineering-constrained optimization problems confirm the potential of IFTTA to solve real-world optimization problems.

Objective: To evaluate the optimal choice of traditional Chinese exercises (TCEs) for improving bone mineral density in postmenopausal women through a network meta-analysis. Methods: Chinese and English databases were searched, including China National Knowledge Infrastructure, Chongqing VIP, PubMed, Web of Science and Cochrane Library. The outcomes included BMD of lumbar L2-L4, femoral neck, Ward’s triangle, and greater trochanter. Standardized mean differences (SMD) and 95% confidence intervals (CI) were used to assess the correlation between each group of interventions, and surface under the cumulative ranking (SUCRA) was used to rank the best interventions. Results: A total of 20 randomized controlled trials (RCTs) including 1933 subjects and six interventions:( Tai Chi (TC), Baduanjin (BDJ), Wuqinxi (WQX), Yijinjing (YJJ), Tai Chi plus calcium supplementation (TA), and Baduanjin plus calcium supplementation (BA)) were analyzed. Regarding the BMD of the lumbar L2-L4: TC [SMD= 0.99 (0.62,1.37)], BDJ [SMD= 2.12 (1.39,2.85)], TA [SMD= (1.12(0.17,2.07)] and BA [SMD= 2.24 (1.16,3.31)] were superior in increasing BMD of lumbar L2-L4 relative to No exercise intervention (NEI). Regarding the BMD of the femoral neck: TC [SMD= 1.24 (0.70,1.78)] and BA [SMD= 3.77 (1.98,5.56)] were superior in increasing BMD of femoral neck relative to NEI. Regarding the BMD of the ward’s triangle: TC [SMD= 1.63 (1.09,2.17)] was superior in increasing the BMD of the ward’s triangle relative to NEI. Regarding the BMD of the greater trochanter: TC [SMD= 0.98 (0.28,1.68)] was superior in increasing the BMD of the greater trochanter relative to NEI. TC topped the SUCRA with BMD of lumbar L2-L4: 53.8, femoral neck: 74.9, Ward’s triangle:86.9 and greater trochanter: 77.7. Conclusion: Four TCEs (TC, BDJ, TA and BA) are all effective in partially improving BMD indicators in postmenopausal women, while TC was effective on all four BMD indicators, which seems to be recommended as the most suitable exercise modality for postmenopausal women.