(1) Background: ‘Slope’ refers to the position faced by golfers on the course. Research on the recruitment strategies of thoracolumbar erector spinae during golf swings on different slopes may help us to understand some underlying mechanisms of lower back pain. (2) Purpose: The purpose of the present study is to assess electromyography (EMG) patterns of the erector spinae muscles (ES) and the kinematics of the trunk and swing parameters while performing golf swings on three different ground slopes: (1) no slope where the ball is level with the feet (BLF), (2) a slope where the ball is above the feet (BAF), and (3) a slope where the ball is below the feet (BBF). Furthermore, the present study evaluates the effect of slope on the kinematics of the trunk, the X-factor angle, and the hitting parameters. (3) Methods: Eight right-handed recreational male golfers completed five swings using a seven-iron for each ground slope. Surface electromyograms from the left and right sides of the ES thoracolumbar region (T8 and L3 on the spinous process side) were evaluated. Each golf swing was divided into five phases. Kinematics of the shoulder, trunk, and spine were evaluated, and the ball speed, swing speed, carry, smash factor, launch angle, and apex were measured using Caddie SC300. (3) Results: The muscle activity of the BAF and BBF slopes was significantly lower than that of the BLF slope during the early follow-through phase of the thoracic ES on the lead side (i.e., left side) and during the acceleration and early follow-through phases of the lumbar ES on the lead side. The lead and trail side (i.e., right side) lumbar ES were more active during acceleration than the thoracic ES. Additionally, the trends of the lead and trail sides of the thoracolumbar regions on the three slopes were found to be the same across the five phases. Trunk angle and X-factor angles had no significant differences in address, top of backswing, or ball impact. The maximum separation angles of the X-factor appeared in the early phase of the downswing for all the three slopes. Regarding smash factor and launch angle, there were no significant differences between the three slopes. The ball speed, swing speed, carry, and apex were higher on BLF than on BAF and BBF slopes. (4) Conclusion: The findings suggest that amateur golfers face different slopes with altered muscle recruitment strategies. Specifically, during the acceleration phase of the golf swing, the BAF and the BBF slopes, compared with the BLF slope, significantly underactivated the lead side thoracolumbar erector spinae muscles, thereby increasing the risk of back injury. Changes in muscle activity during critical periods may affect neuromuscular deficits in high-handicap players and may have implications for the understanding and development of golf-related lower back pain. In addition, the X-factor angle was not affected by the slope, however, it can be found that the hitting parameters on the BLF slope are more dominant than on the other slopes.

Background: Dancers undergo extensive training, resulting in enhanced lower extremity muscle function, flexibility, and stability compared to the general population. However, research on joint loading mechanisms in professional dancers during walking is limited. Objective: This study aimed to investigate the gait characteristics of professional dancers and compare them with non-dancers from a biomechanical perspective. Methods: A comparative gait analysis was performed on 30 dancers (10 each of modern, ballet, and Korean dance) and 10 non-dancers. The study assessed peak joint moment, peak joint power, and joint work at the knee and ankle joints while walking on a flat surface. Results: Ballet group showed longer step cycles (1.30 ± 0.06 s), whereas modern group had shorter cycles (1.11 ± 0.07 s) but higher walking speeds (1.07 ± 0.04 s). Ballet group also had a longer stance phase (64.53% ± 3.46%), while Korean (41.53% ± 4.66%) and modern (41.93% ± 2.95%) groups had larger swing phases. Modern group displayed significantly higher negative ankle joint work (−0.059 ± 0.022 J/kg), ballet (1.49 ± 0.11 Nm/kg) and Korean group (1.53 ± 0.41 Nm/kg) showed higher peak knee joint moments compared to normal group. Conclusion: These findings highlight the distinct gait patterns of dancers, with ballet and Korean dancers showing greater knee joint loading and modern dancers exhibiting unique ankle joint dynamics. Tailored rehabilitation and injury prevention strategies are crucial for their long-term health and performance sustainability.

This study aims to evaluate the biomechanical effects of static stretching (SS) and dynamic stretching (DS) on balance abilities through a systematic review and meta-analysis. Following the PRISMA and PERSIST guidelines, a comprehensive search was conducted in July 2024 across PubMed, Web of Science, Cochrane, Embase, and EBSCO databases for randomized controlled trials assessing the influence of SS and DS on balance abilities in healthy adult populations. A total of twelve studies involving 308 participants were included in this analysis. The primary meta-analysis revealed that static stretching (SS) significantly impaired static balance abilities compared to dynamic stretching (DS), with an effect size of −0.05. Additionally, regression analysis identified stretching duration as a significant source of heterogeneity in static balance, highlighting considerable biomechanical variation. No significant changes were observed for center of pressure (COP) or dynamic balance. Bubble charts illustrated that as stretching duration increased, the effect size on static balance decreased, with multiple effect sizes clustering around the 20 s–200 s duration. Overall, dynamic stretching (DS) is superior to static stretching (SS) in enhancing balance abilities among healthy populations, particularly regarding static balance. Regression analysis indicated that stretching duration is a critical biomechanical factor influencing static balance, with optimal effects observed within the range of 20s to 200s.

BACKGROUND: A warm-up (WU) exercises boost performance during a subsequent exercise. However, the physi-ological benefits obtained from performing a prior warm-up exercise may be lost during the transition phase as mus-cle temperature declines. We examined the effects of the administration of local passive warming (LPW) during the transition phase on lower body power output, as assessed by countermovement jump (CMJ) and Wingate anaerobic tests (WAnT). METHODS: We performed a randomized crossover design experiment (N.=10). Following a 10-min warm-up ex-ercise, the subjects either (1) rested in a sitting position (CON), (2) performed a standardized WU exercise, or (3) underwent an LPW using customized water-perfused pads on the quadriceps and hamstrings for 15 min. The subjects then performed a CMJ and a standardized 30-sec WAnT.RESULTS: CMJ height was higher in the LPW and WU relative to the CON (P=0.0142 and 0.0171, respectively) while no difference was found between the WU and LPW (P=0.2530). The knee angular peak velocity and acceleration of the concentric contraction during the CMJ was higher in the LPW and WU as compared to the CON (P<0.05 for all). However, the average power during the WAnT was reduced in the LPW relative to the WU (P=0.0096). Further analysis revealed that the initial power decline (P=0.0271) in the LPW partly explained the lower power used during the WAnT.CONCLUSIONS: LPW improved CMJ performance but showed no positive effect on WAnT. LPW may provide dif-ferentiated performance benefits depending on the types of exercise that follows.

Background: the objective of this study is to evaluate gait symmetry in female dancers of different dance styles aged 19–21 years. The findings would enable us to understand the effects of long-term training on dancers’ gait. Material and methods: 21 dancers (8 modern dancers, 6 ballet dancers, and 7 Korean dancers) and 15 normal participants completed three validated walking tests at normal speed on a 5 m × 1 m walking track. Results: The modern dancer group showed a significant difference from the control group in terms of step length symmetry index. The right hip sagittal plane ROM was smaller in both the ballet dancer group and the Korean dancer group than in the control group. There was a significant difference in sagittal plane hip ROM in the Korean dancer group compared with the control group. The hip symmetry index in the horizontal plane was greater in all three groups of dancers than in the control group. Conclusions: Long-term training between different dance styles leads to different gait asymmetry effects in dancers.