Journal of Physical Fitness and Sports Medicine

Official journal of the Japanese Society Physical Fitness and Sports Medicine

Online First

The Journal of Physical Fitness and Sports Medicine (JPFSM)

[Volume 12, Number 6 November 25, 2023] Special Issue


Yanagisawa, Y., et al. : Rehabilitation for Returning to Sports in Individuals with Sports-induced Pelvic Injuries—A Narrative Review
Received: August 17, 2023 / Accepted: September 11, 2023

The purpose of this narrative review is to outline pelvic injuries caused by sports, and to clarify their trends, treatment, and management. We describe the rehabilitation for sports injuries of the pelvis, with a focus on pelvic avulsion injuries and pelvic bone stress fractures. This narrative review of fifteen articles published in the last 10 years (from 2013 to 2023) reveals a dearth of new rehabilitation knowledge regarding sports-induced pelvic injuries.


Inagaki, N., et al. : Anatomy to understand pelvic trauma: structure and function of several ligaments around the sacroiliac and pubic symphysis, and bone mineral density of the pelvic bones
Received: August 8, 2023 / Accepted: September 11, 2023

This review is based on the literature published between 2000 and 2023 and presents an up-to-date evidence-based discussion of anatomical considerations relevant to the management of pelvic trauma. In addition, it discusses the significance of the pelvic ligaments in stabilizing the pelvic ring and of bone mineral density (BMD) in fragility fracture of the pelvis (FFP), which is becoming increasingly common in today’s aging societies. Following an overview of the anatomy and function of the sacroiliac joint (SIJ), the pubic symphysis, and the surrounding ligaments, the suitability of the widely used Young-Burgess classification of high-energy impact pelvic ring fractures, which emphasizes the role of the ligaments in pelvic ring injuries, is discussed. Based on the current body of knowledge, using 2.5 cm of pubic symphysis diastasis as the determinant for surgical intervention for anterior-posterior compression fracture is questioned, and evaluation under anesthesia and lateral stress radiography for accurate diagnosis and treatment planning is proposed instead. The review underscores the need for further research on how the pelvic ligaments can provide optimal stability in the treatment of various types of pelvic fracture. On the other hand, for fragility fracture of pelvis (FFP) in older adults caused by low-energy trauma, the emphasis is on the fragility of the bones. To better manage FFP, the importance of understanding the distribution of BMD in the pelvis is highlighted. Dual-energy X-ray absorptiometry is a common method for measuring BMD, but it has drawbacks. The advantages of measuring BMD using Hounsfield units on computed tomography scans as an alternative method are discussed. An understanding of these issues may lead to better management of the increasing number of FFP cases in older people with reduced BMD.

[Volume 13, Number 1 January 25, 2024]

Regular Article

Yasuda, A., et al. : Effects of stimulation conditions and subcutaneous tissue properties on acupressure-induced changes in blood circulation of human tendons
Received: March 13, 2023 / Accepted: May 9, 2023

The purpose of this study was to investigate the effects of stimulation conditions (pressing force and frequency) and subcutaneous tissue properties (thickness and hardness) on the changes in tendon blood circulation caused by acupressure. Before and after acupressure, blood circulation of the Achilles tendon was measured using red laser lights. Acupressure was applied to the Achilles tendon for 3-min under one of three conditions. The following four conditions (including no stimulation condition) with different combinations of pressing forces and frequencies were established; 1) 50N and 1.5Hz, 2) 25N and 3.0Hz, 3) 25N and 1.5Hz, and 4) no stimulation. In addition, the thickness and hardness of subcutaneous tissue at the acupressure-stimulated site were measured. The change in total hemoglobin (corresponding to blood volume) showed a significant main effect of condition, but the effects of time and the interaction between condition and time were not. On average, the most significant increase in tendon blood volume was observed in the 50N and 1.5Hz condition, although the post-hoc test showed no significant difference. The subcutaneous tissue thickness and hardness were not significantly correlated with tendon blood volume changes after stimulation in any of the three conditions. In conclusion, the present results indicate that acupressure under the conditions of pressing force 50N and frequency 1.5Hz changed tendon blood circulation the most, though not based on exact statistical results. Furthermore, the subcutaneous tissue thickness and hardness (including tendon) have no effect on tendon blood circulation induced by stimulation.

Short Communication

Honoka I., et al. : Investigation of the effective standing posture for increasing activity of the pelvic floor muscles: A cross-sectional study
Received: September 14, 2022 / Accepted: June 27, 2023

Pelvic floor muscle (PFM) exercises have been shown to strengthen the PFM function and improve urinary incontinence (UI) symptoms. Several studies have focused on voluntary PFM activity changes among various supine postures. However, few studies have investigated standing postures that promote PFM contraction. Since patients often complain of UI symptoms in the standing position, knowing which posture during voluntary PFM contraction in the standing position its activity increases would be useful from the viewpoint of issuing exercise instructions and for prevention. This study aimed to investigate adequate standing postures for PFM contraction and included nine healthy women. All participants performed maximum voluntary contraction (MVC) of PFM in six standing postures: neutral, abduction, adduction, neutral-external rotation, abduction-external rotation, and adduction-external rotation. The MVC of PFM, adductor magnus muscle, and internal oblique muscles were measured in each posture, and muscle activities were recorded using surface electromyography. We compared muscle activity, with and without hip joint external rotation, in the neutral, abduction, and adduction positions, and discovered increased muscle activity of PFM in standing postures with hip joint external rotation than in standing positions without hip joint external rotation (p <0.01). Since PFM contracts in conjunction with hip adductors and external rotators, the activity of PFM may have been higher in the standing posture with the hip external rotation. Selecting the effective posture is important to increase PFM activity.

Zhenfei Z., et al. : Strength adaptation to short-term isometric training to volitional failure depends on initial specific tension in the elbow flexors
Received: February 10, 2023 / Accepted: July 18, 2023

Objective: We tested a hypothesis that the individuals with low maximal voluntary isometric contraction relative to muscle cross-sectional area (MVC/mCSA) would have greater strength gain, compared to those with high MVC/mCSA in an early stage from beginning of isometric training to volitional failure. Design & Methods: Male adults (n = 24; 22.4 ± 2.5 years, 174.1 ± 6.5 cm, 75.8 ± 14.1 kg) conducted a 3-week isometric training to volitional failure (60-80%MVC, 2-3 times/weeks, 3 sets/session) in elbow joint flexion with 90° flexed of each arm. Based on the relationship between MVC and mCSA before the intervention, we assigned 16 arms to the higher group (HIGH), 14 to the lower group (LOW) and 18 to the mean group (MEAN). Before the intervention and at the beginning of every week, we measured MVC (myometer) and muscle thickness of anterior upper arm (ultrasound). The mCSA was derived from the muscle thickness. Results: The 3-week isometric training to volitional failure increased MVC in all groups, but the relative change in MVC through the intervention was higher in LOW than in HIGH and MEAN groups. Conclusion: The current findings support to the abovementioned hypothesis.

[Volume 13, Number 2 March 25, 2024]

Regular Article

Kobayashi, T., et al. : Relationship between school sports club membership and depressive symptoms among new recruits of the Japan Self-Defense Force: a longitudinal study
Received: May 9, 2023 / Accepted: July 21, 2023

The relationship between participation in extracurricular school club activities in adolescence and subsequent depressive state experiences in adulthood, after joining the workforce, is unclear. The present study aimed to explore this relationship in new recruits of the Japan Ground Self-Defense Force (JGSDF). In April 2013, 925 recruits of the JGSDF, all of whom were male and aged 18–27 years, were enrolled. Club activity status during high school was categorized as follows: participated in sports club, participated in nonsport club, or no club participation. Depressive symptoms were assessed with the 20-item version of the Center for Epidemiologic Studies Depression scale (CES-D), at the baseline survey and a second survey conducted 2 months later, in June 2013. Analysis of covariance was used for association between club activity status and changes in CES-D scores. After 2-month period, results showed significantly higher average of CES-D score changes for participants with nonsport club activities (β = 3.90, 95% confidence interval = 2.22–6.71) or those with no club activities (β = 2.24, 95% confidence interval = 0.20–2.94), compared to those with sports clubs. These findings were adjusted for age, baseline CES-D score, regular exercise, smoking status, alcohol consumption, sleep duration, and breakfast habits. Recruits without a history of sports club participation may be at higher risk of developing depressive symptoms than those who participated in sports club. Our results may be useful for the early detection of people who are susceptible to depression engaged in occupations such as the JDSF.

Fuke, R., et al. : The Characteristics of Youth Sports Specialization among Japanese Baseball Players
Received: May 30, 2023 / Accepted: August 10, 2023

In this study, the characteristics of the athletic careers of Japanese college baseball players were identified, and relationships between their athletic careers and levels of performance and injury were analyzed. A questionnaire survey was conducted for 589 players in teams affiliated with the All-Japan University Baseball Federation; the relationship between their background in competitive activity and levels of performance in competitive experience was analyzed with a χ2 test. In total, 541 players participated in the survey. The survey results showed that the average age at which they started playing baseball was 7.8±1.8 years, and the average age at which they specialized in baseball was 10.0±3.2 years. In terms of athletic experience and the college performance level, the χ2 test showed a significant association (χ2=8.83, Cramer’s V=0.133, p<0.05). Moreover, significantly more rosters specialized before 12 years of age, with experience in other sports, and significantly fewer rosters specialized after 13 years of age, with experience in other sports (p<0.05). Therefore, childhood sports experience may influence performance levels of college players, and Japanese baseball players tend to specialize early.

Hirata, A., et al. : Assessment of adverse events and near-misses during voluntary community-driven sports activities by community residents: A cross-sectional study
Received: June 20, 2023 / Accepted: September 4, 2023

Although physical activities have many health benefits, adverse events and near-misses, such as injuries and falls, can occur during these activities. This study aimed to assess the occurrence of adverse events and near-misses during sports activities conducted independently by community residents. A survey questionnaire was sent via the internet to the leaders or directors of sports organizations at six public sports centers or associations. In total, 108 individuals answered the survey, with 60% male and 40% female respondents. Individuals aged 50–69 years accounted for 60% of the total number of respondents. All respondents were asked about their experiences of adverse events and near-misses within the past three years: the reports of these incidents were obtained using the recall method. Duplicate adverse events and near-misses were identified based on the sports discipline; time of occurrence; and sex and age of person involved to determine if there were duplicate reports. Most of the respondents' activities as staff were performed once a month, with each activity lasting 1–2 h. Forty-five adverse events were reported, including 26 injuries, 13 falls, and 6 others (such as heat stroke, vertigo, and presyncope). Twenty-four near-misses were reported, including 12 near-collisions with people or objects, five near falls, and seven other incidents. We found that approximately 30% of the respondents experienced adverse events, suggesting the need for documentation of adverse events, implementation of safety measures, and proper safety education for operating staff.

[Volume 13, Number 3 May 25, 2024]

Regular Article

Nakano, S., et al. : Effects of combination of concentrated Kurozu supplementation and endurance training on mitochondrial enzyme activity and energy metabolism in mice
Received: April 21, 2023 / Accepted: September 7, 2023

We examined the effects of endurance training with chronic pre-exercise concentrated Kurozu supplementation on mitochondrial enzyme activity and energy metabolism in Institute of Cancer Research (ICR) mice. Mice were divided into a control group, an endurance training group, and an endurance training + concentrated Kurozu supplementation group. Mice were orally supplemented with water or concentrated Kurozu solution (500 mg/kg body weight/day) for 3 weeks. The mice in the training group were subjected to exercise on a treadmill (20–25 m/min × 30 min, five times/week) starting 30 min after the supplementation. The maximal activity of citrate synthase in the plantaris muscle in the endurance training + concentrated Kurozu supplementation group was significantly higher than that in the control group (p < 0.01). The maximal activity of ß-hydroxyacyl coenzyme dehydrogenase (β-HAD) in the soleus muscle in the endurance training + concentrated Kurozu supplementation group was significantly higher than that in the other two groups (p < 0.05 for both). In the final week, significant negative correlation between blood lactate concentration after exercise and soleus β-HAD activity was observed. These findings suggest that endurance training with concentrated Kurozu supplementation increases mitochondrial enzyme activity and might enhance lipid metabolism during exercise.