Junya Aizawa

• Tokyo Medical and Dental University

Objectives Although insufficient delivery of oxygen might be a factor in physical and perceived fatigue, the relationship between exposure to hyperbaric oxygen (HBO) and recovery from perceived fatigue remains unexplained. The purpose of this study was to investigate the effects of exposure to HBO after long-duration, medium-intensity training on r...

OBJECTIVE: To analyze the association between asymmetry in the reactive strength index (RSI) during single-limb vertical continuous jumps (SVCJs) and isokinetic knee extensor strength in athletes who have undergone anterior cruciate ligament reconstruction (ACLR) DESIGN: Cross-sectional study METHODS: This study included 75 athletes (40 female athl...

Background After anterior cruciate ligament reconstruction (ACLR), asymmetry is likely to persist in single-leg (SL) vertical jump and drop jump performance than in SL hop distance. However, its relationship with the return to sport (RTS) remains unclear. Hypothesis/Purpose This study aimed to determine the association between vertical jump perfor...

BACKGROUND: Recovery of the isokinetic knee extensor strength on the operated side following anterior cruciate ligament (ACL) reconstruction is commonly calculated as a ratio with the value from the non-operated side serving as the denominator. However, the validity of the values of the non-operated side remains unclear. OBJECTIVE: This study aimed...

This study aimed to determine differences in the hip abductor muscle activity during clam exercise at different hip flexion and femoral anteversion angles. Thirty healthy females were divided into two groups based on the femoral anteversion angle: the excessive femoral anteversion group and the normal group. Clam exercise was performed at three dif...

OBJECTIVES: To determine the association between second anterior cruciate ligament (ACL) injury within 2 years after ACL reconstruction and knee function at 6 postoperative months. DESIGN: Retrospective cohort study. METHODS: We included patients who had undergone primary ACL reconstruction. Knee strength was measured using an isokinetic dynamomete...

Background Medial tibial stress syndrome (MTSS) is a running-related injury of the lower extremities. After returning to competition, there are often recurring episodes of MTSS. Therefore, it is important to prevent the onset and recurrence of MTSS among long-distance runners. This case–control study aimed to compare the kinematics and kinetics of...

Purpose: To identify the factors associated with anterior cruciate ligament return to sport after injury (ACL-RSI) scores in patients awaiting ACL reconstruction (ACLR). Methods: This was a retrospective cross-sectional observational study conducted at a single clinical center. We recruited patients scheduled for primary ACLR, aged 16-45 years,...

Objective: To compare forward head posture (FHP) in natural and corrected head postures between patients with nonspecific neck pain (NSNP) and controls, and to clarify the relationship between natural- and corrected-head posture angle differences and deep cervical flexor function. Design: Survey study Setting: Patients with NSNP were outpatients at...

Purpose: To determine characteristic changes in subjective knee function, kinesiophobia, and psychological readiness to return to sports between scores taken before anterior cruciate ligament reconstruction (ACLR) and those taken 6 months post-ACLR. Methods: Thirty-two participants (median age, 20.0 years) were included. Subjective knee function...

Context: Deficits in knee extension strength after anterior cruciate ligament reconstruction have been a major problem. The inadequate recovery of the knee extension strength of surgical limb reportedly delays return to sports and increases reinjury risk. Accordingly, the early detection of knee extension strength deficits after reconstruction may...

Background The association of the reactive strength index (RSI) during single-limb vertical continuous jumps (SVCJs) with single-limb hop tests in athletes after anterior cruciate ligament reconstruction (ACLR) is unclear. Thus, this study aimed to confirm the measurement properties of the RSI during SVCJs in athletes with ACLR at the phase of dete...

Abstract Background Information about specific factors of physical function that contribute to psychological readiness is needed to plan rehabilitation for a return to sports. The purpose of this study was to identify specific physical functions related to the psychological readiness of patients aiming to return to sports 6 months after reconstruct...

The cranial vertical angle (CVA) and cranial rotation angle (CRA) are used in clinical settings because they can be measured on lateral photographs of the head and neck. We aimed to clarify the relationship between CVA and CRA photographic measurements and radiographic cervical spine alignment. Twenty-six healthy volunteers were recruited for this...

Introduction: Kinesiophobia is a fear of physical movement and activity and is known to impact return to sports and second injury after anterior cruciate ligament reconstruction. Objective: To determine the association among landing biomechanics, knee pain, and kinesiophobia in athletes following anterior cruciate ligament reconstruction. Desig...

Background The association of the reactive strength index (RSI) during single-leg vertical continuous jumps (SVCJs) with single-leg hop tests in athletes after anterior cruciate ligament reconstruction (ACLR) is unclear. Thus, this study aimed to confirm the measurement properties of the RSI during SVCJs in athletes with ACLR at the phase of determ...

Objectives: The objective of the present study was to compare the cross-sectional areas (CSAs) of the gluteus medius on the affected and unaffected sides to assess long-term changes after total hip arthroplasty (THA). Methods : The data for 23 women who were diagnosed with unilateral hip osteoarthritis and who underwent primary THA via the posterol...

Background: Information about specific factors of physical function that contribute to psychological readiness is needed to plan rehabilitation for a return to sports. The purpose of this study was to identify specific physical functions related to the psychological readiness of patients aiming to return to sports 6 months after reconstruction. We...

Background /objectives: For biomechanical studies using jump-landing tasks, many researchers set the criteria for judging success or failure of the trial. Failed trials are usually removed from the analysis. However, the kinetics and kinematics during tasks included in failed trials might be important for understanding the mechanisms and risk facto...

Background/objective Injury-related fear during sport activities are major psychological factors inhibiting a person’s return to sports (RTS) following anterior cruciate ligament reconstruction (ACLR). Currently, there are no studies that quantitatively analyse the open-ended questionnaire for knee injury-related fear in post-ACLR athletes. The pur...

Background Most patients with anterior cruciate ligament (ACL) injury undergo ACL reconstruction (ACLR) with the expectation of being able to return to sport (RTS) at the same level of the competition as before the injury. The magnitude and asymmetry of landing impact are important post-ACLR functional variables related to increased ACL strain and...

BACKGROUND Knee strength weakness is a major problem frequently observed in patients during postoperative rehabilitation following anterior cruciate ligament reconstruction (ACLR). OBJECTIVE To investigate whether knee strength normalized to muscle volume could better detect side-to-side differences than that normalized to body weight following AC...

Background When planning rehabilitation and conditioning for performance enhancement and a return to sports after anterior cruciate ligament reconstruction, identifying the elements of physical function associated with single-leg hop is important. The purpose of this study was to clarify the relationship between single-leg hop distances in three di...

Background This study aimed to determine the relationships between athletic identity and sport commitment and return to sports (RTS) status in athletes after anterior cruciate ligament reconstruction (ACLR). Methods Thirty-nine participants post-ACLR (8–24 months) were included in this cross-sectional study. Measures included the athletic identity...

Purpose To investigate the relationship between single-leg hop distance (SLHD), normalized body height, and return-to-sports (RTS) status after anterior cruciate ligament reconstruction (ACLR) and to identify the cut-off value for SLHD on the operated side. Methods Seventy-three patients after primary ACLR (median 13.5 months) participated in this...

Objective To determine the association of psychological readiness to return to sports preoperative and 6 months post-reconstruction in athletes with anterior cruciate ligament (ACL) injury. Design Retrospective cohort study. Setting Clinical center of sports medicine. Participants Fifty athletes, aged 16-45 years, were included in this study. Pa...

Background A single-leg vertical jump height (SLVJ) may reflect knee extension strength more than a single-leg hop for distance (SLH). This study aimed to examine the relationships between the isokinetic knee extension torque, SLH, and SLVJ after anterior cruciate ligament reconstruction (ACLR). Methods Forty-four patients post-ACLR (median 12.0 m...

Background: When planning rehabilitation and conditioning for performance enhancement and a return to sports after anterior cruciate ligament reconstruction, identifying the elements of physical function associated with one-leg hop is important. The purpose of this study was to clarify the relationship between one-leg hop distances in 3 directions...

Background: High psychological readiness is an important element for returning to sports after anterior cruciate ligament (ACL) reconstruction. Identifying factors that contribute to psychological readiness is essential for planning interventions to return to play. No studies have used multivariate analysis to clarify factors associated with psycho...

Background: On a questionnaire administered to athletes who had undergone anterior cruciate ligament reconstruction (ACLR), some answered "yes" to a question regarding return to sports (RTS) at the preinjury level despite having lower postoperative subjective athletic performance (PoSAP) intensity compared with preoperative levels. Purpose: To i...

Background: On a questionnaire administered to athletes who had undergone anterior cruciate ligament reconstruction (ACLR), some answered "yes" to a question regarding return to sports (RTS) at the preinjury level despite having lower postoperative subjective athletic performance (PoSAP) intensity compared with preoperative levels. Purpose: To inv...

[Purpose] Direct arch measurement under quantitative partial weight bearing (DAM-under-qPWB) has been developed as a new method for measuring the medial longitudinal arch. This study examined the reliability and validity of DAM-under-qPWB with respect to the navicular drop test (NDT). [Participants and Methods] The participants were 12 young adults...

PurposeThe anterior cruciate ligament-return to sports after injury (ACL-RSI) scale assesses the psychological impact of returning to sports (also referred to as psychological readiness) after ACL reconstruction. The aim of this study was to evaluate important measurement properties of the Japanese version of ACL-RSI scale.Methods Ninety-three part...

[Purpose] The purpose of this study was to determine the effects of extracorporeal shock wave therapy (ESWT) on the pain threshold of athletes with chronic pain during their sport season. [Participants and Methods] Seven collegiate American football players with pain lasting for over four weeks participated in this study. The affected sites were fo...

Objectives: To investigate the immediate effects of thoracic spine self-mobilization in patients with mechanical neck pain. Study design: Randomized, controlled trial. Background: Thoracic spine self-mobilization is performed after thoracic spine thrust manipulation to augment and maintain its effects. To the best of our knowledge, no study ha...

Background: Improving lower limb muscle strength is important in preventing progression of osteoarthritis (OA) and its symptoms. Exercise with branched-chain amino acid (BCAA) supplementation has been reported to affect protein anabolism in young and elderly persons. However, few studies provided daily BCAAs for patients with OA. Objective: This st...

[Purpose] The purpose of this study was to examine limb-dominance and gender differences in the magnitude of the ground reaction force during single-leg lateral jump-landings. We hypothesized that the peak ground reaction force would be larger in the non-dominant leg compared to that in the dominant leg and would be larger in females compared to th...

[Purpose] This study aimed to clarify the correlations between the kinematics of the pre-landing flight phase and ground reaction force during single-leg anterior jump-landing. [Subjects and Methods] Fifteen healthy adults were included in the study. The sagittal angles of the trunk, pelvis, and lower extremities were measured 50 msec before initia...

Background: Joint angle data from healthy subjects are necessary as baseline information. Objective: To analyze the problems of patients who struggle with activities of daily living (ADL) due to restricted range of motion and to provide ADL guidance based on objective data. Method: An electromagnetic three-dimensional tracking system (FASTRAK)...

[Purpose] The importance and effect of hip joint geometry on hip abductor muscle strength are well known. In addition, other perioperative factors are also known to affect hip abductor muscle strength. This study examined the relative importance of factors affecting hip abductor muscle strength after total hip arthroplasty. [Subjects and Methods] T...

The aim of this study was to analyze the effect of teeth clenching on dynamic balance at jump-landing. Twenty-five healthy subjects performed jump-landing tasks with or without teeth clenching. The first three trials were performed with no instruction; subsequently, subjects were ordered to clench at the time of landing in the following three trial...

[Purpose] Fatigue may be an important contributing factor to non-contact anterior cruciate ligament injuries in sports. The purpose of this study was to evaluate the effects of controlled lower limb fatigue, induced by a short-term, high-intensity exercise protocol, on the profile of the ground reaction force during landings from single-leg anterio...

[Purpose] The correlations of peak vertical ground reaction force and sagittal angles during single-leg lateral jump-landing with noncontact anterior cruciate ligament injury remain unknown. This study aimed to clarify the correlations between kinematics and impact force during lateral jump-landing. [Subjects and Methods] Twenty active males were i...

This study examined the effects and feasibility of a twice-weekly combined therapy of branched-chain amino acids (BCAAs) and exercise on physical function improvement in frail and pre-frail elderly people requiring long-term care. We used a crossover design in which the combination of exercise and nutritional interventions was carried out twice a w...

Purpose: The purpose of this study was to assess the reliability, validity, and responsiveness of the Japanese version of the Lower Extremity Functional Scale (LEFS-J)． Methods: A total of 112 outpatients with lower-extremity musculoskeletal dysfunction participated in the study. Psychometric testing include reliability by internal consistency (Cro...

[Purpose] This study compared the efficacy of passive and active stretching techniques on hamstring flexibility. [Subjects] Fifty-four healthy young subjects were randomly assigned to one of three groups (2 treatment groups and 1 control group). [Methods] Subjects in the passive stretching group had their knees extended by an examiner while lying s...

Purpose The aims of this study were to translate and culturally adapt the Patient-Specific Functional Scale (PSFS) and validate the Japanese version of the PSFS (PSFS-J) in outpatients with neck pain. Methods The PSFS was translated and adapted into Japanese in accordance with the published guidelines. A total of 103 outpatients with neck pain were...

Angles of the shoulder joint are usually defined in each of the sagittal, coronal, and horizontal planes passing through the center of the shoulder joint. One of the problems with this method is the difficulty of describing some positions of the shoulder joint such as the anterolaterally elevated position. In 2005, the International Society of Biom...

Purpose: The aim of this study was to show highly reliable normal values and three-dimensional characteristics for final range of motion during active movements of the upper extremity joints, and to develop a database from healthy participants, with the advantage of this database lying in the methods of defining shoulder axial rotation angle and o...

Previous research has shown that mastication reduces shifts in the center of gravity of persons standing still. The present research was conducted to determine whether mastication improves reactive balance in the standing position in response to unanticipated external disturbances. The subjects were 32 healthy male adults (mean age 21.1 years, stan...

Study design: Translation and psychometric testing. Objective: To translate and culturally adapt the Neck Disability Index (NDI) and to assess the reliability and validity of the Japanese version of the NDI (NDI-J) in Japanese outpatients with neck pain. Summary of background data: To date, no previous report exists on the translation process...

Highly reliable information on the range of motion (ROM) required to perform activities of daily living (ADL) is important to allow rehabilitation professionals to make appropriate clinical judgments of patients with limited ROM of the upper extremity joints. There are, however, no data available that take full account of corrections for gimbal-loc...

[Purpose] This study examined the relationship between craniovertebral (CV) angle and the activity of the sternocleidomastoid (SCM) during performance of the cranio-cervical flexion test (CCFT) by healthy subjects. [Subjects] Ten volunteer subjects without neck pain enrolled in this study. [Methods] SCM electromyographic (EMG) activity was recorded...