Association between motor symptoms of Parkinson's disease and swallowing disorders.

BACKGROUND: Parkinson's disease (PD) presents with motor symptoms that hinder physical activity. This study aimed to thoroughly investigate swallowing dysfunction in patients with PD using videofluoroscopy (VF) and the Movement Disorder Society (MDS)-Unified PD Rating Scale (UPDRS) sub-scores. METHODS: This study was part of an intervention project to evaluate the effectiveness of cervical percutaneous interferential current stimulation in patients with Hoehn and Yahr stages 2-4 PD. Baseline data, including swallowing-related indicators such as VF, were obtained and compared to the MDS-UPDRS sub-scores including rigidity, tremor, postural instability/gait difficulty, and limb scores. RESULTS: Twenty-seven patients were included in this study. In the VF analysis, laryngeal penetration/aspiration, oral cavity residue, epiglottic vallecular residue, and pharyngeal residue were observed with remarkable frequency. The multivariate analysis revealed that the mean rigidity score of UPDRS was an independent and significantly correlated factor with laryngeal penetration/aspiration during the ingestion of 10 mL of water (odds ratio 1.294, 95% confidence interval 1.035-1.617; p = 0.024). CONCLUSION: This study revealed a correlation between muscle rigidity and laryngeal penetration or aspiration risk. The detailed comparative analysis of various individual PD symptoms and swallowing disorders was substantial, which enabled early detection of the risk of swallowing disorder and the implementation of appropriate measures. TRIAL REGISTRATION NUMBER: jRCTs062220013.

Variability in sonographic anterior drawer test measurements of the ankle: Experienced versus beginner examiners.

BACKGROUND: This study aimed to clarify the variability in the measurements of stress sonography of the ankle and determine the effects of examiner experience on the measurements. METHODS: Twenty examiners (10 experienced and 10 beginners) were included in the study. Each examiner performed stress ultrasonography on a patient with a chronic anterior talofibular ligament injury and a patient with an intact ligament using the reverse anterior drawer method. Changes in ligament length before versus after stress were determined. The same 20 examiners performed ultrasonography on two other patients with an injured or intact ATFL using the anterior drawer method. The length change values and variance were compared between the groups using t-tests and F-tests. RESULTS: Using the reverse anterior drawer method, the change in the anterior talofibular ligament length was 3.3 mm (range, 2.2-4.8 mm) in the experienced group and 2.7 mm (0.0-4.1 mm) in the beginner group for the ligament injured patient. The length changes for the patient with intact anterior talofibular ligament were 0.5 mm (0.1-0.9 mm) and 0.4 mm (-0.1-1.5 mm) in the experienced and beginner groups, respectively. There were no significant intergroup differences in measurement amount (P = 0.37) or variance (P = 0.72). Similarly, using the anterior drawer method, no significant differences between the groups were found in measurement amount or variance. CONCLUSION: The quantitative evaluation of stress sonography of the ankle was variable regardless of examiner experience or stress method, particularly in patients with an anterior talofibular ligament injury. The amount of variability appeared to be unacceptably large for clinical application. Our study results highlight the need for technical standardization.

Analysis of the suprahyoid muscles during tongue elevation: High-density surface electromyography as a novel tool for swallowing-related muscle assessment.

BACKGROUND: High-density surface electromyography (HD-sEMG) has enabled non-invasive analysis of motor unit (MU) activity and recruitment, but its application to swallowing-related muscles is limited. OBJECTIVE: We aimed to investigate the utility of HD-sEMG for quantitatively evaluating the MU recruitment characteristics of the suprahyoid muscles during tongue elevation. METHODS: We measured the sEMG activity of the suprahyoid muscles of healthy participants during tongue elevation using HD-sEMG. Maximum voluntary contraction (MVC) was measured, followed by data collection during sustained and ramp-up tasks to capture suprahyoid muscle activity. Changes in the temporal/spatial MU recruitment patterns within individual suprahyoid muscles were analysed. RESULTS: This study enrolled 16 healthy young adults (mean age: 27.8 ± 5.3 years; eight males and eight females). Increasing muscle force corresponded to a decrease in modified entropy and correlation coefficient and an increase in the coefficient of variation. No significant differences were observed between male and female participants. CONCLUSION: The results of this study, consistent with those observed in other muscles, such as the vastus lateralis muscle, suggest that HD-sEMG is a valuable and reliable tool for quantitatively evaluating MU recruitment in the suprahyoid muscles. This measurement technique holds promise for novel assessments of swallowing function.

Functional electrostimulation therapy for vastus medialis decreases the varus thrust during gait.

[Purpose] This study aimed to investigate whether modification of vastus medialis activity can delay the varus thrust. [Participants and Methods] Ten participants (Kellgren-Laurence grades I: n=2, II: n=6, and III: n=2) diagnosed with knee osteoarthritis were enrolled. The intervention involved free walking on a 10-m walkway at any speed after donning a functional electrical stimulation set to contract the vastus medialis before heel contact. Using a Vicon Nexus ground reaction force meter and a wireless electromyograph DELSYS, varus thrust, maximal knee extension angle, maximal knee adduction moment, and vastus medialis onset time were assessed both before and after intervention. [Results] A significant difference in varus thrust was detected from before to after the intervention (2.7 ± 1.1° vs. 2.2 ± 1.3°). Both the vastus medialis activation time (-0.06 ± 0.09 vs. -0.21 ± 0.1) and the knee-joint extension angle (8.7 ± 5.1° vs. 5.5 ± 5.9°) decreased following intervention, whereas the knee adduction moment significantly increased (0.50 ± 0.20° vs 0.56 ± 0.18°). [Conclusion] Wearing the functional electrical stimulation set caused the vastus medialis to act earlier in response to heel strike, thereby improving the knee-joint extension angle and suppressing varus thrust.

Age-specific incidence of joint disease in paediatric patients with haemophilia: A single-centre real-world outcome based on consecutive US examination.

INTRODUCTION: Joint health is one of the most important factors contributing to a healthy life in patients with haemophilia. Recent study revealed that starting early prophylaxis was not enough to prevent joint disease in most paediatric patients with haemophilia. AIM: In this study, we aimed to determine the age-specific incidence of acute joint disease during childhood at single haemophilia treatment centre (HTC). METHOD: The joint health in 48 patients was evaluated based on consecutive US testing for 5 years at annual multidisciplinary comprehensive care. RESULTS: During the study period, 23 patients (47.9%) had no joint disease since the initial examination, whereas 13 patients (27.0%) showed development from negative to positive findings. The incidence of joint disease increased with age: 0% in preschool, 5.3% in elementary school, 14.3% in junior high school and 35% beyond high school age. Among the 13 patients who developed joint disease, two experienced acquired synovitis that resolved during the follow-up period. Statistical analysis revealed that the patients who routinely underwent follow-up by the HTC exhibited a significantly lower incidence of joint disease than did those followed up at other institutions (p < .001). CONCLUSION: These results indicated that close check-up, including routine joint examination using US as well as frequent assessment of pharmacokinetic profile at the HTC, might play an important role in avoiding joint disease among paediatric patients with haemophilia.

Detecting side-to-side differences of lower limb biomechanics during single-legged forward landing after anterior cruciate ligament reconstruction.

BACKGROUND: Motion analysis can be used to evaluate functional recovery after anterior cruciate ligament (ACL) reconstruction; however, the biomechanics parameters of the lower limb that are specifically altered in ACL-reconstructed knees compared to the contralateral side are not well understood. This retrospective study aimed to compare side-to-side differences in lower limb biomechanics during the first 100 milliseconds (ms) after initial contact in a single-leg forward landing task. METHODS: Using three-dimensional motion analysis, lower joint kinematic and kinetic variables were measured 8-10 months postoperatively in 22 patients who had undergone ACL reconstruction. We determined side-to-side differences in lower limb biomechanics over the 100-ms timeframe after landing, and receiver operating characteristic (ROC) curve analyses were performed to calculate the area under the curve (AUC) for parameters showing significant side-to-side differences. RESULTS: During the 100-ms timeframe after landing, 58 kinematic and kinetic items showed significant side-to-side differences. Side-to-side differences in lower limb biomechanics over the 40-ms timeframe after landing existed. The ROC curve analysis identified 11 items with AUC values ≥ 0.70, including hip flexion, abduction moment, and knee joint power, and their AUC values were not significantly different. CONCLUSION: Hip flexion/abduction moment and knee power after GRF max could be used as outcomes for assessing functional recovery in patients who have undergone ACL reconstruction.

Validity and reliability of the loco-check questionnaire after cross-cultural adaptation for Indonesia.

BACKGROUND: A large number of the elderly in Indonesia are affected by an increasing number of disabilities, with reduced mobility being one of the causes. Locomotive syndrome may cause decreased mobility, and its progression can impair the activities of daily living. Early screening is essential to halt its progression. The loco-check, a screening tool for locomotive syndrome, is available in English. A cross-cultural adaptation of this tool for an Indonesian version is important to maintain the validity of the questionnaire for its implementation in Indonesia. The aim of this study was to obtain a valid Indonesian version of the loco-check questionnaire that has been adapted as per Indonesian language and cultural conventions (through a cross-cultural adaptation process). METHODS: The subjects in the study were community-dwelling geriatrics over 65 years of age who were recruited using consecutive non-probability judgment sampling according to the inclusion criteria. This study, conducted from February to October 2019, was divided into two stages consisting of: (1) language and cultural adaptation; (2) validity and reliability testing. The seven items on the loco-check were translated using forward-backward translation. The final questionnaire was generated through an expert panel discussion. The validity and reliability were evaluated using concurrent validity and Cronbach's alpha using SPSS Version 23.0. RESULTS: In the first stage, the first and second trials showed a strong correlation between the English and Indonesian versions of the questionnaire with r = 0.997 (p < 0.001) and r = 0.825 (p = 0.003), respectively. The final Indonesian version of the loco-check had a good validity and reliability with r = 0.981 (p < 0.001) and Cronbach's alpha of 0.768, respectively. CONCLUSION: The Indonesian cross-cultural adaptation of the loco-check questionnaire is a valid and reliable general questionnaire that could enable screening for locomotive syndrome in Indonesia.

Readability and quality of online patient resources regarding knee osteoarthritis and lumbar spinal stenosis in Japan.

BACKGROUND: This study aimed to quantify the readability and quality of online patient resources on knee osteoarthritis and lumbar spinal stenosis in Japan. METHODS: Three search engines (Google, Yahoo, and Bing) were searched for the terms knee osteoarthritis and lumbar spinal stenosis. The first 30 websites of each search were screened. Duplicate websites and those unrelated to the searched diseases were excluded. The remaining 125 websites (62 on knee osteoarthritis, 63 on lumbar spinal stenosis) were analyzed. The text readability was assessed using two web-based programs (Obi-3 and Readability Research Lab) and lexical density. Website quality was evaluated using the DISCERN score, Clear Communication Index, and Journal of American Medical Association benchmark criteria. RESULTS: Readability scores were high, indicating that the texts were difficult to understand. Only 24 (19%) and six (5%) websites were classified as average difficulty readability according to Obi-3 and Readability Research Lab, respectively. The overall quality of information was low, with only four (3%) being rated as having sufficient quality based on the Clear Communication Index and Journal of American Medical Association benchmark criteria. None of the websites satisfied the DISCERN quality criteria. CONCLUSIONS: Patient information on Japanese websites regarding knee osteoarthritis and lumbar spinal stenosis were difficult to understand. Moreover, the quality of the websites was insufficient. Orthopaedic surgeons should contribute to the creation of high-quality easy-to-read websites to facilitate patient-physician communication.

Impact of pain in other body regions on the foot-specific quality of life in patients with hallux valgus.

OBJECTIVES: The purpose of this study was to clarify the prevalence of pain outside the foot, and to determine the associations of pain outside the foot with foot-specific quality of life (QOL) in patients with hallux valgus. METHODS: Patients scheduled to undergo hallux valgus surgery were recruited. Patients answered whether they experienced disabling pain in 13 body regions other than the foot. Foot-specific QOLwas assessed using the Self-Administered Foot Evaluation questionnaire (SAFE-Q). Foot pain was quantified using the visual analogue scale (VAS). Patient characteristics, including age, sex, comorbidity, anxiety, and depression, were also surveyed. The association between pain elsewhere and the SAFE-Q and pain VAS scores were assessed using univariate and multivariate analyses. RESULTS: Of 102 patients, 55 (54%) experienced pain other than the foot. All SAFE-Q subscale scores were lower, and pain VAS was higher in patients with pain elsewhere than in patients without. In the multivariate analysis, an increase in the number of pain regions was independently associated with a decrease in SAFE-Q scores and an increase in pain VAS. CONCLUSION: More than half of the patients with hallux valgus experienced pain elsewhere. The presence of pain elsewhere was associated with poorer foot-specific QOL and severer foot pain.

Swallowing Exercise Evaluated Using High-Density Surface Electromyography in Patients with Head and Neck Cancer: Supplementary Analysis of an Exploratory Phase II Trial.

Background and Objectives: Muscle strength evaluation using high-density surface electromyography (HD-sEMG) was recently developed for the detailed analysis of the motor unit (MU). Detection of the spatial distribution of sEMG can detect changes in MU recruitment patterns resulting from muscle-strengthening exercises. We conducted a prospective study in 2022 to evaluate the safety and feasibility of transcutaneous electrical sensory stimulation (TESS) therapy using an interferential current device (IFCD) in patients with head and neck squamous cell carcinoma (HNSCC) undergoing chemoradiotherapy (CRT), and reported the safety and feasibility of TESS. We evaluated the efficacy of swallowing exercises in patients with HNSCC undergoing CRT and determined the significance of sEMG in evaluating swallowing function. Materials and Methods: In this supplementary study, the patients performed muscle-strengthening exercises five days a week. The association of the effects of the exercises with body mass index, skeletal muscle mass index, HD-sEMG, tongue muscle strength, and tongue pressure were evaluated. Results: We found significant correlations between the rate of weight loss and skeletal muscle mass index reduction and the rate of change in the recruitment of the MU of the suprahyoid muscle group measured using HD-sEMG. Conclusions: We believe that nutritional supplementation is necessary in addition to muscle strengthening during CRT.

Kinematic effects of lateral wedged insoles in patients with medial knee osteoarthritis.

[Purpose] To examine the effect of lateral wedged insoles on the rotation mechanism of the knee joint in patients with knee osteoarthritis. [Participants and Methods] The participants included 11 patients with medial knee osteoarthritis. We asked all participants to stand up from a 40-cm-high chair, and we measured the rotation angle of the knee joint during the movement. The standing motion was performed under four conditions: barefoot and with 7-, 10-, and 13-mm lateral wedged insoles. We also measured four healthy participants as controls for comparison. [Results] During the standing motion, we internally rotated the tibia relative to the femur. In healthy participants, we measured 19.6° internal rotation of the tibia relative to the femur. Patients with knee osteoarthritis had internal rotations of approximately 9.8° when barefoot and 7.1°, 6.4°, and 7.1° when wearing lateral wedged insoles of 7, 10, and 13 mm, respectively. [Conclusion] Lateral wedged insoles do not modify the knee joint rotation motion of patients with knee OA to the correct style.

Dose-response Rehabilitation Organized By Pror In Out-patients With Chronic Cerebrovascular Disorder: A single-center retrospective cohort study.

PURPOSE: We aimed to investigate whether out-patient rehabilitation with the same concept as physiatrist and registered therapist operating rehabilitation (PROr) would improve activities of daily living in out-patients with chronic cerebrovascular disorder and whether the improvements were related to the frequency and/or time of therapy. METHODS: Out-patients with chronic cerebrovascular disorder, who visited a clinic affiliated with a university hospital for at least a month between April 2010-September 2020, were retrospectively selected. Changes in the functional independence measure (FIM) from the first visit to the 12th month were calculated. Patients were stratified into two subgroups: improved and non-improved groups. The frequency and time of physical and occupational therapies and total rehabilitation were compared between the groups. RESULTS: Initially, 174 patients were selected and 125 were excluded based on the exclusion criteria. Three patients terminated rehabilitation because of improvements. In 18 of 49 patients, FIM improved at the 12th month by 4.9 [3.1-6.8] (mean [95% CI]). The frequency was ∼2 times/week with no differences between the groups. Physical therapy time/day was higher in the improved group (74.7 [66.7-82.7] min) than the non-improved group (50.7 [44.3-57.0] min; P<0. 001). The total rehabilitation time/day was 121.9 [107.8-136.0] min in the improved group, which was higher than the non-improved group: 97.9 [87.7-107.9] (P=0.001). CONCLUSIONS: Approximately 40% of the patients displayed improved FIM even during the chronic phase, and the improved out-patients took PROr for at least 108 min/day and twice a week. A longer rehabilitation time would be reinforced by patients' motivation.

Preoperative In-Hospital Rehabilitation Improves Physical Function in Patients with Pancreatic Cancer Scheduled for Surgery.

Low preoperative physical function in cancer patients is associated with postoperative complications; however, there have been no reports on the benefits of in-hospital preoperative rehabilitation on preoperative physical function in patients with pancreatic cancer. Therefore, the aim of this study was to quantitatively determine the effects of preoperative in-hospital rehabilitation provided under the supervision of a physiotherapist, on preoperative physical function in patients with pancreatic cancer. The study subjects were 26 patients (15 males, 11 females; age 71.2 ± 8.5 years, range: 51-87 years), including four patients with preoperative chemotherapy, scheduled for surgery for pancreatic cancer. Muscle strengthening exercises and aerobic exercises were conducted 11.9 ± 5.1 days prior to surgery. Cardiopulmonary exercise testing, 6-minute walk distance, and the Functional Independence Measure score were measured before and after the rehabilitation program. We also investigated the relation between the rehabilitation program and incidence of postoperative complications. All 26 study patients completed the preoperative rehabilitation program and no adverse events were noted. Peak oxygen uptake during cardiopulmonary exercise testing and 6-minute walk distance increased significantly after the rehabilitation program. The Functional Independence Measure score remained constant throughout the intervention. No wound infection, delirium, deep vein thrombosis, or respiratory complications were encountered postoperatively. In-hospital preoperative rehabilitation under the supervision of a physiotherapist significantly improved physical function and maintained physical activity in patients with pancreatic cancer. Such improvements may contribute toward preventing serious postoperative complications, resulting in better outcomes.

Thermoregulatory responses of lower limb amputees during exercise in a hot environment.

Lower limb amputees (LLAs) have less skin surface required for sweating; thus, the ability to dissipate heat from the body may decrease and the risk of heat illness may increase during exercise in a hot environment. However, no study has compared the thermoregulatory responses during exercise between LLAs and able-body (AB) individuals with different body surface areas. This study aimed to compare the thermoregulatory responses of LLAs with those of AB individuals during exercise in a hot environment. Seven LLAs (LLA group) and 7 able-body individuals (AB group) participated in the study. A 60% peak power output of arm crank upper-body exercise was performed for 60 min in a hot environment (32 °C, 50% relative humidity). There was no difference in the increase in rectal temperature (LLA: 0.8 ± 0.2 °C, AB: 0.8  ± 0.2 °C) and mean skin temperature between the groups during the 60-min exercise. In the LLA group, the accumulated local sweat rate of the thigh during exercise was significantly higher on the non-cut side than on the cut side (64.6 ± 43.0 mg/h vs. 37.0 ± 27.2 mg/h, p < 0.05). The total sweat rate was significantly higher in the LLA group than in the AB group (1.18 ± 0.37 kg/h vs. 0.84 ± 0.10 kg/h, p < 0.05). Thermal sensation and comfort were lower in the LLA group than in the AB group. Different heat loss responses were observed in the AB and LLA groups during exercise in the heat. The LLA group compensates for sweating on the cut side due to an increase in sweat loss on the intact limb, thereby preserving appropriate thermoregulation during exercise.

Attenuation of core temperature elevation and interleukin-6 excretion during head-out hot water immersion in elderly people.

[Purpose] Previous studies have demonstrated a link between core body temperature and interleukin-6 production. Recent studies have reported that 20 minutes of head-out immersion in hot water (42°C) increased serum interleukin-6 levels in young males. This study aimed to compare the efficacy of head-out immersion in hot water (42°C) on serum interleukin-6 levels in seven elderly (66-75 years old) and eight young males (21-32 years old). [Participants and Methods] Venous blood samples were drawn at rest, immediately after head-out immersion in hot water (42°C), after 1 hour, and after 2 hours. Levels of serum interleukin-6, tumor necrosis factor-α, and high-sensitivity C-reactive protein; blood cell counts; and core temperature were measured. [Results] It was found that 20 minutes of head-out immersion in hot water (42°C) increased the core temperature in both the elderly and young participants; however, the rise in core temperature was more attenuated in elderly participants. Serum interleukin-6 levels were significantly higher in young participants 1 hour after the head-out immersion in hot water (42°C); however, serum interleukin-6 levels did not change in elderly participants. Serum tumor necrosis factor-α and high-sensitivity C-reactive protein levels remained constant throughout the study the elderly and young participants. [Conclusion] The current study demonstrated that head-out immersion in hot water (42°C) more attenuated core temperature and interleukin-6 levels in elderly participants than in young participants. We assert that these differences are likely to be related to age-related changes in core temperature regulation and muscle fibers.

Whole-body vibration enhances effectiveness of "locomotion training" evaluated in healthy young adult women.

[Purpose] Locomotion training is recommended as a countermeasure against locomotive syndrome. Recently, whole-body vibration has been clinically applied in rehabilitation medicine. Therefore, we aimed to investigate the preliminary effectiveness of whole-body vibration on locomotion training. [Participants and Methods] Overall, 28 healthy adult females were randomly assigned to either a locomotion training group using a whole-body vibration device (whole-body vibration group, n=14) or training on the flat floor (non-whole-body vibration group: n=14). Participants conducted two sets of locomotion training twice a day and three times a week for 12 weeks. [Results] A significant difference was observed in the group factor for all outcome measures and in the before and after the training factor for Timed Up and Go test. After the training, knee muscle strength, dynamic balance, and mobility function in the whole-body vibration group were significantly improved compared with the non-whole-body vibration group. In the whole-body vibration group, the Timed Up and Go time after the training was significantly shorter compared with that before training. [Conclusion] The results suggest that locomotion training with whole-body vibration can improve the physical functions in healthy adult females and locomotion training using whole-body vibration might enhance the effectiveness of locomotion training.

Symmetry tensiomyographic neuromuscular response after chronic anterior cruciate ligament (ACL) reconstruction.

PURPOSE: Quadriceps muscle weakness is common following anterior cruciate ligament (ACL) reconstruction. Tensiomyography is a recent method to assess muscle strength, and one that also enables evaluation of individual muscles. The purpose of this study was to evaluate motor unit recruitment and investigate the effects on mechanical and contractile characteristics of the quadriceps and hamstring muscles after chronic ACL reconstruction. METHODS: This study recruited 20 participants: three males and seven females at 24 months after ACL reconstruction, and three males and seven females with no history of knee injury (control group). All participants underwent tensiomyographic assessment of each thigh muscle, bilaterally, to measure maximal displacement, delay time, contraction time, sustained time, and half-relaxation time. The following muscles were evaluated: vastus medialis, vastus lateralis, rectus femoris, semitendinosus, and biceps femoris. Mean normalized muscle peak torque, mean normalized maximum work done, mean angle to peak torque, and mean time to peak torque based on isokinetic peak torque measurements were calculated in both groups. RESULTS: Maximal displacement of the vastus medialis on the ACL reconstruction side was significantly higher than for the non-ACL reconstruction side and for the control group (p = 0.026). Half-relaxation time for the vastus medialis and biceps femoris was significantly higher for both the ACLR and non-ACLR sides compared with the control group (p = 0.001). There were also significant differences in symmetry in the vastus medialis and biceps femoris when comparing results between the ACL reconstruction group and the control group (p = 0.034, p = 0.043, respectively). CONCLUSIONS: The presence of strength and symmetry deficits in the vastus medialis and biceps femoris suggests the need for long-term post-operative training following ACL reconstruction. There are clinical relevant improvements of muscle response and velocity as well as muscle strength in patients with chronic ACLR. LEVEL OF EVIDENCE: II.

Exercise loading for cardiopulmonary assessment and evaluation of endurance in amputee football players.

[Purpose] It is difficult for amputees to perform conventional cardiopulmonary exercise testing. Values were determined for two-legged, one-legged, and two-armed exercise testing in healthy adult males (Study 1), for comparison with preliminary measurements of endurance in amputee football players (Study 2). [Participants and Methods] In Study 1, cardiopulmonary exercise testing was performed in healthy adult males. Correlations between oxygen uptake in two-legged and one-legged/two-armed exercise were calculated and a comparison was made between one-legged exercise and two-armed exercise for each measured value. In Study 2, cardiopulmonary exercise testing was performed on male amputee football players using a two-arm-driven ergometer. The measured values obtained for healthy adult males and amputee football players were compared. [Results] In Study 1, peak work rate and peak heart rate values of healthy participants were significantly higher in two-armed exercise than in one-legged exercise. The correlation between peak oxygen uptake values for two-legged and one-legged exercise was decreased. In Study 2, peak work rate of two-armed exercise was significantly higher in amputee football players than in healthy participants. [Conclusion] Study 1 suggested that musculoskeletal factors might have greater significance for one-legged exercise than for two-armed exercise. Study 2 suggested that para-sports, including amputee football, may contribute to physical strength and health maintenance in lower leg amputees.

Sex differences in variances of multi-channel surface electromyography distribution of the vastus lateralis muscle during isometric knee extension in young adults.

PURPOSE: The aim of the present study was to compare spatial electromyographic potential distribution during force production between healthy young female and male using multi-channel surface electromyography (multi-SEMG). METHODS: Thirty healthy subjects (15 females) performed sustained isometric knee extension at 10% maximal voluntary contraction (MVC) task for 120 s. Multi-SEMG signals from the vastus lateralis muscle were detected and the modified entropy, coefficient of variation (CV), and correlation coefficient determined. RESULTS: The modified entropy and CV showed significant interaction and difference between females and males at all time points during the 10% MVC task. The correlation coefficient in females was significantly lower at 90 and 120 s than that of males. CONCLUSIONS: The multi-SEMG potential distribution pattern in females showed more varied motor unit recruitment during sustained low-intensity isometric contraction than that of males. Variations in motor unit recruitment may result from recruitment and/or de-recruitment of motor units.

The Acute Effects of Static and Cyclic Stretching on Muscle Stiffness and Hardness of Medial Gastrocnemius Muscle.

This study aimed to clarify the acute effects of static stretching (SS) and cyclic stretching (CS) on muscle stiffness and hardness of the medial gastrocnemius muscle (MG) by using ultrasonography, range of motion (ROM) of the ankle joint and ankle plantar flexor. Twenty healthy men participated in this study. Participants were randomly assigned to SS, CS and control conditions. Each session consisted of a standard 5-minute cycle warm-up, accompanied by one of the subsequent conditions in another day: (a) 2 minutes static stretching, (b) 2 minutes cyclic stretching, (c) control. Maximum ankle dorsiflexion range of motion (ROM max) and normalized peak torque (NPT) of ankle plantar flexor were measured in the pre- and post-stretching. To assess muscle stiffness, muscle-tendon junction (MTJ) displacement (the length changes in tendon and muscle) and MTJ angle (the angle made by the tendon of insertion and muscle fascicle) of MG were measured using ultrasonography at an ankle dorsiflexion angle of -10°, 0°, 10° and 20° before and after SS and CS for 2 minutes in the pre- and post-stretching. MG hardness was measured using ultrasound real-time tissue elastography (RTE). The results of this study indicate a significant effect of SS for ROM maximum, MTJ angle (0°, 10°, 20°) and RTE (10°, 20°) compared with CS (p < 0.05). There were no significant differences in MTJ displacement between SS and CS. CS was associated with significantly higher NPT values than SS. This study suggests that SS of 2 minutes' hold duration significantly affected muscle stiffness and hardness compared with CS. In addition, CS may contribute to the elongation of muscle tissue and increased muscle strength.