Relationship of Clubhead Speed With Explosive Power and Muscle Strength of the Hip and Trunk Joints of Elite Golfers.

ABSTRACT: Suhara, H, Nariai, M, Takagi, T, Akiyama, K, Nagashima, J, and Shiraki, H. Relationship of clubhead speed with explosive power and muscle strength of the hip and trunk joints of elite golfers. J Strength Cond Res 37(4): 859-865, 2023-In golf, the driving distance of the ball is affected by the clubhead speed (CHS) on impact. We aimed to clarify the relationship between CHS and explosive power and muscle strength of the hip and trunk muscles in elite golfers (male age: 19.6 ± 1.9 years, male handicap: 4.4 ± 0.9, female age: 17.7 ± 1.4 years, and female handicap: 6.2 ± 0.7). A correlational design was used to assess the relationships between CHS and strength (hip extension-flexion and trunk rotation of peak torque at an isokinetic 60 and 180°·s -1 angular velocity) and CHS and power (countermovement jump [CMJ]; peak power and jump height; backward overhead medicine ball [BOMB] throw). Fourteen each of male and female elite golfers were included. The CHS during the golf swing was measured using a Doppler radar measurement device (Trackman). A correlation analysis between each measurement and CHS ( p ≤ 0.05) was conducted. We found that the peak torque of right hip extension at an angular velocity of 180°/s (male, r = 0.67; female, r = 0.61), peak CMJ power (male: r = 0.63, female: r = 0.75), and BOMB throw distance (male, r = 0.6; female, 0.6) were positively correlated with CHS in both male and female golfers. These results suggest that the extensor strength of the lower extremities and trunk, centered on the hip joint in the sagittal plane, is important for physical fitness and muscle strength measurement related to CHS. Conversely, concentric trunk rotator strength and CHS were not correlated, suggesting that concentric trunk rotator strength may not be actively involved in CHS.

Influence of Surveillance Methods in the Detection of Sports Injuries and Illnesses.

Background: Epidemiological data on sports injuries and illnesses depend on the surveillance methodology and the definition of the health problems. The effect of different surveillance methods on the data collection has been investigated for overuse injuries, but not for other health problems such as traumatic injuries and illnesses. Purpose: The purpose of this study was to investigate the new surveillance method developed by the Oslo Sports Trauma Research Center (OSTRC), which is based on any complaint definition (new method), to identify health problems compared with the traditional surveillance method, which is based on time loss definition. Study design: Descriptive epidemiology study. Methods: A total of 62 Japanese athletes were prospectively followed-up for 18 weeks to assess differences in health problems identified by both new and traditional methods. Every week, the athletes completed the Japanese version of the OSTRC questionnaire (OSTRC-H2.​JP), whereas the teams' athletic trainers registered health problems with a time loss definition. The numbers of health problems identified via each surveillance method were calculated and compared with each other to assess any differences between their results. Results: The average weekly response rate to the OSTRC-H2.​JP was 82.1% (95% CI, 79.8-84.3). This new method recorded 3.1 times more health problems (3.1 times more injuries and 2.8 times more illnesses) than the traditional method. The difference between both surveillance methods' counts was greater for overuse injuries (5.3 times) than for traumatic injuries (2.5 times). Conclusions: This study found that the new method captured more than three times as many health problems as the traditional method. In particular, the difference between both methods' counts was greater for overuse injuries than for traumatic injuries. Level of evidence: 2b.

Sports Injury Surveillance Systems and Guidelines in Japan: A Systematic Review.

This systematic review aimed to identify sports injury surveillance systems (ISSs) and injury surveillance guidelines (ISGs) developed and currently used in Japan. Additionally, the extent to which ISSs and ISGs developed overseas are employed in Japan was also examined. A systematic search of electronic databases was performed in March 2021. Prospective studies that investigated sports injuries and targeted Japanese athletes or sports in Japan were included to identify the following: (1) details of the ISSs or ISGs developed among sports in Japan, and (2) characteristics of studies focusing on sports in Japan employing ISSs or ISGs developed overseas and the method of use. A total of five ISSs developed among sports in Japan were included, most of which were based on insurance benefits or condolence payment systems. In total, 23 studies used ISSs or ISGs developed overseas, more than half of which were used as a resource for the development of other data collection tools or methods, indicating that the definition of injury and/or classification of items are modified based on the needs among sports in Japan. This review highlights the necessity of establishing club-based or organisational ISSs and ISGs that are appropriate for sports in Japan.

A Biomechanical Comparison Among Three Kinds of Rebound-Type Jumps in Female Collegiate Athletes.

BACKGROUND: Single-legged drop jumps (SDJ), single-legged repetitive jumps (SRJ), and single-legged side hops (SSH) are often used as plyometric training and functional performance tests. Differences in the kinetics and kinematic characteristics of lower extremity joints during these jumps are unclear. HYPOTHESIS/PURPOSE: The purpose of this study was to investigate the joint motion and mechanical work of the takeoff leg from foot contact to foot-off during SDJ, SRJ, and SSH in the sagittal and frontal planes in female athletes. It was hypothesized that the joint motion and mechanical work of the lower extremity joints during the SDJ and SRJ would be larger than the SSH in the sagittal plane, those during the SSH would be larger than the SDJ and SRJ in the frontal plane, and during SRJ would be larger than SDJ. STUDY DESIGN: Cross-sectional study. METHODS: Seventeen female collegiate athletes participated and performed the SDJ (0.15-m box height), and SRJ and SSH (by crossing two lines 0.3 m apart). Three-dimensional coordinate data and ground reaction forces were collected. Contact time, jump height, jump index (i.e., the jump height divided by the contact time) of the SDJ and SRJ, and the total times of the SSH were calculated. Range of motion (ROM) from touchdown to the lowest center of mass, and the positive and negative (mechanical) work from touchdown to foot-off were analyzed. RESULTS: There were no significant differences in jump performance variables. Compared to the SSH, the SDJ and SRJ had significantly larger ankle and knee ROM and positive and negative work at the lower extremity joints, except for positive work at the hip joint, in the sagittal plane (p < 0.05). Compared to the SDJ and SRJ, the SSH had a significantly larger ankle ROM and positive work at the knee joint in the frontal plane (p < 0.05). Compared to the SDJ, the SRJ had a significantly larger ROM and negative work at each lower extremity joint in the frontal plane (p < 0.05). CONCLUSION: Although there were no significant differences in the jump performance variables, different characteristics of the takeoff leg ROM and mechanical work were found between three kinds of rebound-type jump tests. These findings may help clinicians choose jump methods to assess lower extremity function and to design plyometric training programs in sports and clinical fields. LEVEL OF EVIDENCE: 3b.