Tomoya Ishii, S. Sasada, Shinya Suzuki, T. Komiyama
Surface electromyographic activity (sEMG) of the biceps brachii (BB) during weak elbow flexion has been reported to immediately increase after strong elbow flexion even while exerting consistent force; this phenomenon is called “post-contraction potentiation” (PCP). To determine whether the central nervous system is involved in PCP, we investigated the effect of transcranial direct current stimulation (tDCS) and transcranial magnetic stimulation (TMS) of the primary motor cortex (M1) during PCP. Initially, the participants were instructed to perform successive muscle contraction tasks with different forces: 2% (Test 1); then 25%, 50%, or 100% (conditioning contraction [CC]); and again 2% (Test 2) of maximum voluntary contraction (MVC). In subsequent experiments, the CC intensity was set at 50% MVC, and tDCS (anodal, cathodal, and sham) was applied to the M1 before the task. In the last experiment, TMS was applied to M1 to evaluate the excitability of the corticospinal tract during Tests 1 and 2. The CC intensity at 50% or 100% MVC generated PCP, but didn’t at 25% MVC. Anodal tDCS significantly decreased the magnitude of PCP, while cathodal tDCS showed an increase in magnitude compared to sham tDCS. The BB motor-evoked potential amplitude during Test 2 was lower compared to that during Test 1. These findings suggest that changes in the excitability of the corticospinal tract and resultant changes in the activation pattern of motor unit activity play a role in generating PCP.
{"title":"Transcranial direct current stimulation of primary motor cortex modulates post-contraction potentiation","authors":"Tomoya Ishii, S. Sasada, Shinya Suzuki, T. Komiyama","doi":"10.7600/JPFSM.10.13","DOIUrl":"https://doi.org/10.7600/JPFSM.10.13","url":null,"abstract":"Surface electromyographic activity (sEMG) of the biceps brachii (BB) during weak elbow flexion has been reported to immediately increase after strong elbow flexion even while exerting consistent force; this phenomenon is called “post-contraction potentiation” (PCP). To determine whether the central nervous system is involved in PCP, we investigated the effect of transcranial direct current stimulation (tDCS) and transcranial magnetic stimulation (TMS) of the primary motor cortex (M1) during PCP. Initially, the participants were instructed to perform successive muscle contraction tasks with different forces: 2% (Test 1); then 25%, 50%, or 100% (conditioning contraction [CC]); and again 2% (Test 2) of maximum voluntary contraction (MVC). In subsequent experiments, the CC intensity was set at 50% MVC, and tDCS (anodal, cathodal, and sham) was applied to the M1 before the task. In the last experiment, TMS was applied to M1 to evaluate the excitability of the corticospinal tract during Tests 1 and 2. The CC intensity at 50% or 100% MVC generated PCP, but didn’t at 25% MVC. Anodal tDCS significantly decreased the magnitude of PCP, while cathodal tDCS showed an increase in magnitude compared to sham tDCS. The BB motor-evoked potential amplitude during Test 2 was lower compared to that during Test 1. These findings suggest that changes in the excitability of the corticospinal tract and resultant changes in the activation pattern of motor unit activity play a role in generating PCP.","PeriodicalId":55847,"journal":{"name":"Journal of Physical Fitness and Sports Medicine","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42136447","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In various sports, high-intensity training reduces the oral immune function of the player. The effect of volleyball training camp on salivary immune function is unclear. This study aimed to investigate the effect of pre-season training on salivary immune function in elite collegiate volleyball players. Twenty-one elite collegiate volleyball players (mean age: 19.6 ± 1.1 years, mean height: 185.2 ± 7.8 cm) participated in this observational study. Saliva samples were taken on Day-1 (First day) and Day-11 (Final day) during pre-season training camp. Fatigue was measured using a VAS (visual analog scale) every day during the training camp period. Oral immune function was assessed in terms of secretory immunoglobulin A (s-SIgA) secretion rate and nitric oxide (s-NO) secretion rate. The s-NO secretion rate showed no significant change from Day-1 (0.69 ± 0.49 µmol/min) to Day-11 (0.56 ± 0.33 µmol/min). How-ever, the s-SIgA secretion rate on Day-11 (28 ± 16 µg/min) was significantly lower (P < 0.05) than that on Day-1 (35 ± 18 µg/min). Changes in fatigue scale scores positively correlated with changes in s-NO secretion rate ( r s = .591, P < 0.01), but not with changes in s-SIgA secretion rate ( r s = .411, P = 0.06). In this study, the concentration of s-NO stored frozen was determined, but the effect of the storage method on s-NO should be investigated in future studies. In conclu-sion, pre-season volleyball training camp may affect oral immune function as in other sports.
在各种运动中，高强度训练会降低运动员的口腔免疫功能。排球训练营对唾液免疫功能的影响尚不清楚。本研究旨在探讨季前训练对优秀大学排球运动员唾液免疫功能的影响。21名优秀大学生排球运动员(平均年龄:19.6±1.1岁，平均身高:185.2±7.8 cm)参加了本观察性研究。在季前训练营的第1天(第一天)和第11天(最后一天)采集唾液样本。在训练营期间，每天使用视觉模拟量表(VAS)测量疲劳程度。以分泌免疫球蛋白A (s-SIgA)和一氧化氮(s-NO)分泌率评价口腔免疫功能。s-NO分泌率从第1天(0.69±0.49µmol/min)到第11天(0.56±0.33µmol/min)无显著变化。但第11天s-SIgA分泌率(28±16µg/min)显著低于第1天(35±18µg/min) (P < 0.05)。疲劳量表评分的变化与s- no分泌率的变化呈正相关(r s = 0.591, P < 0.01)，与s- siga分泌率的变化无正相关(r s = 0.411, P = 0.06)。本研究测定了冷冻贮藏时s-NO的浓度，但贮藏方式对s-NO的影响有待于进一步研究。综上所述，季前排球训练营与其他运动一样，可能对口腔免疫功能产生影响。
{"title":"Effect of pre-season training camp on oral immune functions in elite collegiate volleyball players","authors":"Ryota Sone, Kenji Yamamoto, K. Ohishi","doi":"10.7600/JPFSM.10.39","DOIUrl":"https://doi.org/10.7600/JPFSM.10.39","url":null,"abstract":"In various sports, high-intensity training reduces the oral immune function of the player. The effect of volleyball training camp on salivary immune function is unclear. This study aimed to investigate the effect of pre-season training on salivary immune function in elite collegiate volleyball players. Twenty-one elite collegiate volleyball players (mean age: 19.6 ± 1.1 years, mean height: 185.2 ± 7.8 cm) participated in this observational study. Saliva samples were taken on Day-1 (First day) and Day-11 (Final day) during pre-season training camp. Fatigue was measured using a VAS (visual analog scale) every day during the training camp period. Oral immune function was assessed in terms of secretory immunoglobulin A (s-SIgA) secretion rate and nitric oxide (s-NO) secretion rate. The s-NO secretion rate showed no significant change from Day-1 (0.69 ± 0.49 µmol/min) to Day-11 (0.56 ± 0.33 µmol/min). How-ever, the s-SIgA secretion rate on Day-11 (28 ± 16 µg/min) was significantly lower (P < 0.05) than that on Day-1 (35 ± 18 µg/min). Changes in fatigue scale scores positively correlated with changes in s-NO secretion rate ( r s = .591, P < 0.01), but not with changes in s-SIgA secretion rate ( r s = .411, P = 0.06). In this study, the concentration of s-NO stored frozen was determined, but the effect of the storage method on s-NO should be investigated in future studies. In conclu-sion, pre-season volleyball training camp may affect oral immune function as in other sports.","PeriodicalId":55847,"journal":{"name":"Journal of Physical Fitness and Sports Medicine","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47227392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The lifestyles connected to the health outcomes were described and trends and situation analysis for smoking in Croatia as well as legislation framework and population impact assessment was presented.
介绍了与健康结果相关的生活方式，并介绍了克罗地亚吸烟的趋势和情况分析，以及立法框架和人口影响评估。
{"title":"Lifestyle and health","authors":"Vlasta Hrabak Žerjavić, V. Kralj, M. Kuzman","doi":"10.7600/jpfsm.6.525","DOIUrl":"https://doi.org/10.7600/jpfsm.6.525","url":null,"abstract":"The lifestyles connected to the health outcomes were described and trends and situation analysis for smoking in Croatia as well as legislation framework and population impact assessment was presented.","PeriodicalId":55847,"journal":{"name":"Journal of Physical Fitness and Sports Medicine","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47315565","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
There is some truth to the saying “You are what you eat.” ... Like an assembly line in reverse, the digestive system takes the food we eat and breaks the complex organic molecules into their chemical subunits. The subunits are molecules small enough to be absorbed into the bloodstream and delivered to body cells. Food molecules ultimately meet one of two fates: they may be used to provide energy for daily activities or they may provide materials for growth and repair of the body.
{"title":"Nutrition and digestion","authors":"Susanna Cocroft","doi":"10.7600/jpfsm.6.468","DOIUrl":"https://doi.org/10.7600/jpfsm.6.468","url":null,"abstract":"There is some truth to the saying “You are what you eat.” ... Like an assembly line in reverse, the digestive system takes the food we eat and breaks the complex organic molecules into their chemical subunits. The subunits are molecules small enough to be absorbed into the bloodstream and delivered to body cells. Food molecules ultimately meet one of two fates: they may be used to provide energy for daily activities or they may provide materials for growth and repair of the body.","PeriodicalId":55847,"journal":{"name":"Journal of Physical Fitness and Sports Medicine","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49314256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Obesity and aging reduce skeletal muscle contractile function, which represents a reduction in muscle quality. Dysfunction of muscle contraction may contribute to a greater risk for diabetes, cardiovascular diseases, and cancer; therefore, the synergistic effects of obesity and aging on muscle function may exacerbate morbidity and mortality. However, evidence di-rectly examining the synergistic effects of obesity and aging on muscle contractile function is lacking and controversial. We recently demonstrated that diet-induced obesity significantly exacerbates contractile dysfunction in aged skeletal muscle. The focus of this review is the effects of obesity on muscle contractile dysfunction in skeletal muscle, particularly during aging.
{"title":"Influence of obesity on skeletal muscle contractile dysfunction in aging","authors":"Hiroaki Eshima","doi":"10.7600/jpfsm.9.199","DOIUrl":"https://doi.org/10.7600/jpfsm.9.199","url":null,"abstract":"Obesity and aging reduce skeletal muscle contractile function, which represents a reduction in muscle quality. Dysfunction of muscle contraction may contribute to a greater risk for diabetes, cardiovascular diseases, and cancer; therefore, the synergistic effects of obesity and aging on muscle function may exacerbate morbidity and mortality. However, evidence di-rectly examining the synergistic effects of obesity and aging on muscle contractile function is lacking and controversial. We recently demonstrated that diet-induced obesity significantly exacerbates contractile dysfunction in aged skeletal muscle. The focus of this review is the effects of obesity on muscle contractile dysfunction in skeletal muscle, particularly during aging.","PeriodicalId":55847,"journal":{"name":"Journal of Physical Fitness and Sports Medicine","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42201619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Ogaki, Gento Otake, Satoko Nakane, Y. Kosasa, Y. Kanno, Ayane Ogura, M. Takemura
To the best of our knowledge, most previous studies regarding the epidemiology of injuries in rugby union (rugby) players have focused on professional players. Therefore, data on injuries in collegiate rugby players in Japan is limited. The purpose of this study was to conduct a prospective injury survey of Japanese male collegiate rugby players over several years and to analyze the injuries that occurred during matches and training according to field position, type of injury, and mechanism of injury. This prospective study initially registered 128 rugby players from one university club. The occurrence of injuries was recorded by athletic trainers during the rugby seasons between 2017 and 2019. The total injury rate (IR) was 7.26 injuries/1000 player-hours (1000 PHs). The match IR (122.73 injuries/1000 PHs) was almost 31.9 times higher than the training IR (3.84 injuries/1000 PHs). Ankle sprains/ligament injuries (17.7%; 1.28 injuries/1000 PHs) were the most common injuries, in addition to acromioclavicular joint injuries in forwards and hamstring strain injuries in backs. The most common injury mechanism was tackling (16.4%). Injury characteristics differed according to field position; therefore, preventive measures according to field position are necessary. Moreover, the high number of tackle injuries suggests that improved tackle skills would help reduce injuries. The IR among Japanese collegiate rugby players was higher than that reported previously. Injury prevention training for collegiate players is necessary to reduce the number of injuries.
{"title":"Descriptive epidemiology of injuries in Japanese male collegiate rugby union players","authors":"R. Ogaki, Gento Otake, Satoko Nakane, Y. Kosasa, Y. Kanno, Ayane Ogura, M. Takemura","doi":"10.7600/jpfsm.9.223","DOIUrl":"https://doi.org/10.7600/jpfsm.9.223","url":null,"abstract":"To the best of our knowledge, most previous studies regarding the epidemiology of injuries in rugby union (rugby) players have focused on professional players. Therefore, data on injuries in collegiate rugby players in Japan is limited. The purpose of this study was to conduct a prospective injury survey of Japanese male collegiate rugby players over several years and to analyze the injuries that occurred during matches and training according to field position, type of injury, and mechanism of injury. This prospective study initially registered 128 rugby players from one university club. The occurrence of injuries was recorded by athletic trainers during the rugby seasons between 2017 and 2019. The total injury rate (IR) was 7.26 injuries/1000 player-hours (1000 PHs). The match IR (122.73 injuries/1000 PHs) was almost 31.9 times higher than the training IR (3.84 injuries/1000 PHs). Ankle sprains/ligament injuries (17.7%; 1.28 injuries/1000 PHs) were the most common injuries, in addition to acromioclavicular joint injuries in forwards and hamstring strain injuries in backs. The most common injury mechanism was tackling (16.4%). Injury characteristics differed according to field position; therefore, preventive measures according to field position are necessary. Moreover, the high number of tackle injuries suggests that improved tackle skills would help reduce injuries. The IR among Japanese collegiate rugby players was higher than that reported previously. Injury prevention training for collegiate players is necessary to reduce the number of injuries.","PeriodicalId":55847,"journal":{"name":"Journal of Physical Fitness and Sports Medicine","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49342242","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. Watanabe, Nanako Kobiki, Takafumi Aoki, M. J. Kremenik, T. Nagano, H. Yano, Eri Oyanagi
The aim of this study was to examine the effects of voluntary exercise on plasma and urinary metabolites and the changes in gut microbiota in mice fed with a high-fat-diet. Healthy male C57BL/6J mice (four-week-old, n = 27) were fed a normal controlled diet (CD) and a high-fat-diet (HFD) for 10 weeks under two conditions: voluntary wheel running (W) and sedentary controlled condition (C). The metabolites in the collected plasma and urine were detected using 1 H-NMR spectroscopy techniques. Also, 16S-rRNA gene next-generation sequencing was carried out on the collected feces. Wheel running activity in HFDW mice was slightly higher than that in CDW mice (p = 0.075). Exercise and diet significantly altered body weight, fat accumulation, and glucose tolerance tests. In plasma, amino acids such as Leu, Ile, Ala and Tyr, were increased by exercise. Diet influenced the metabolites in both the plasma and urine of mice and showed significant differences; in plasma, Leu, Ile, Glu, 3-HB, lactate and acetate, whereas in urine, citrate, trimethylamine (TMA), trimethylamine-N-oxide (TMAO), taurine, hippurate and allantoin. With regard to beta diversity, unweighted UniFrac analysis (principal coordinate analysis: PCoA) showed the difference between CD and HFD mice could be observed under PC1 (22.61%). Although there was substantial overlap between two conditions (C vs. W), HFD groups were positioned in a slightly different area when compared to the C and W conditions. Firmicutes/Bacteroidetes ratio, which might be associated with obesity, in HFD mice was significantly higher than that in CD mice, but not affected by wheel running. Our results suggest that testing in both plasma and urinary metabolites may prove to be a more reliable approach to quantitative metabolite analysis on the effects of exercise-dependent hosts or as an independent alteration of gut microbiota on the hosts.
本研究的目的是研究自愿运动对高脂肪饮食小鼠血浆和尿液代谢物的影响，以及肠道微生物群的变化。选取健康雄性C57BL/6J小鼠(27只，4周龄)，分别饲喂正常控制饮食(CD)和高脂饮食(HFD) 10周，在自主轮跑(W)和久坐控制状态(C)两种条件下，采用1h - nmr技术检测血浆和尿液中的代谢物。并对收集的粪便进行16S-rRNA基因下一代测序。HFDW小鼠的轮跑活力略高于CDW小鼠(p = 0.075)。运动和饮食显著改变了体重、脂肪积累和葡萄糖耐量试验。血浆中亮氨酸(Leu)、赖氨酸(Ile)、亚拉氨酸(Ala)和酪氨酸(Tyr)等氨基酸均因运动而增加。饮食对小鼠血浆和尿液代谢物均有影响，且差异显著;血浆中有亮氨酸、亮氨酸、谷氨酸、3-血红蛋白、乳酸盐和醋酸盐，而尿液中有柠檬酸盐、三甲胺(TMA)、三甲胺- n -氧化物(TMAO)、牛磺酸、尿囊素和尿囊素。在β多样性方面，未加权UniFrac分析(主坐标分析:PCoA)显示，在PC1下，CD和HFD小鼠之间存在差异(22.61%)。尽管两种情况(C和W)之间存在大量重叠，但与C和W条件相比，HFD组的位置略有不同。HFD小鼠的厚壁菌门/拟杆菌门比值显著高于CD小鼠，但不受车轮跑步的影响，该比值可能与肥胖有关。我们的研究结果表明，血浆和尿液代谢物的检测可能被证明是一种更可靠的方法，可以定量分析运动依赖宿主的代谢物影响，或者作为宿主肠道微生物群的独立改变。
{"title":"Effects of voluntary exercise on plasma and urinary metabolites and gut microbiota in mice fed with high-fat-diet","authors":"C. Watanabe, Nanako Kobiki, Takafumi Aoki, M. J. Kremenik, T. Nagano, H. Yano, Eri Oyanagi","doi":"10.7600/JPFSM.9.205","DOIUrl":"https://doi.org/10.7600/JPFSM.9.205","url":null,"abstract":"The aim of this study was to examine the effects of voluntary exercise on plasma and urinary metabolites and the changes in gut microbiota in mice fed with a high-fat-diet. Healthy male C57BL/6J mice (four-week-old, n = 27) were fed a normal controlled diet (CD) and a high-fat-diet (HFD) for 10 weeks under two conditions: voluntary wheel running (W) and sedentary controlled condition (C). The metabolites in the collected plasma and urine were detected using 1 H-NMR spectroscopy techniques. Also, 16S-rRNA gene next-generation sequencing was carried out on the collected feces. Wheel running activity in HFDW mice was slightly higher than that in CDW mice (p = 0.075). Exercise and diet significantly altered body weight, fat accumulation, and glucose tolerance tests. In plasma, amino acids such as Leu, Ile, Ala and Tyr, were increased by exercise. Diet influenced the metabolites in both the plasma and urine of mice and showed significant differences; in plasma, Leu, Ile, Glu, 3-HB, lactate and acetate, whereas in urine, citrate, trimethylamine (TMA), trimethylamine-N-oxide (TMAO), taurine, hippurate and allantoin. With regard to beta diversity, unweighted UniFrac analysis (principal coordinate analysis: PCoA) showed the difference between CD and HFD mice could be observed under PC1 (22.61%). Although there was substantial overlap between two conditions (C vs. W), HFD groups were positioned in a slightly different area when compared to the C and W conditions. Firmicutes/Bacteroidetes ratio, which might be associated with obesity, in HFD mice was significantly higher than that in CD mice, but not affected by wheel running. Our results suggest that testing in both plasma and urinary metabolites may prove to be a more reliable approach to quantitative metabolite analysis on the effects of exercise-dependent hosts or as an independent alteration of gut microbiota on the hosts.","PeriodicalId":55847,"journal":{"name":"Journal of Physical Fitness and Sports Medicine","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47888195","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shin Goto, Shingo Matsuo, M. Iwata, Wakako Tsuchida, Genki Hatano, S. Kataura, Yasuhiro Banno, Y. Asai, Shigeyuki Suzuki
Although static stretching is commonly performed to improve flexibility, it has been reported to have detrimental effects on muscle force and performance. Previous studies have reported that low-intensity and short-duration isometric contraction after static stretching inhibits stretch-induced force loss. However, the detailed effects of low-intensity short-duration isometric contraction after static stretching on flexibility, such as passive torque and stiffness, are currently unclear. Therefore, the current study sought to reveal the effects of low-intensity and short-duration isometric contraction after static stretching on flexibility and muscle force. Sixteen healthy participants (eight men, eight women) performed 300-s static stretching (SS), 300-s static stretching followed by 6-s 30% maximum isometric voluntary contraction (MIVC) (SS-30% MIVC), and 6-s 30% MIVC (30% MIVC) of the right hamstring on three separate days, in random order. Range of motion (ROM) and passive stiffness during knee extension, peak passive torque, and MIVC torque were obtained before and after exercise. ROM and peak passive torque were significantly increased after all exercises, whereas passive stiffness and MIVC torque were significantly decreased after SS only. Moreover, ROM after SS and SS-30% MIVC were significantly greater than that of 30% MIVC, and peak passive torque after SS-30% MIVC was significantly greater than that of SS, while passive stiffness after SS was significantly lower than that of 30% MIVC. These results indicate that low-intensity and short-duration isometric contraction after static stretching is effective for inhibiting stretch-induced force loss while also inhibiting the effects of static stretching on passive
{"title":"Effects of low-intensity and short-duration isometric contraction after static stretching on range of motion, passive stiffness, and isometric muscle force","authors":"Shin Goto, Shingo Matsuo, M. Iwata, Wakako Tsuchida, Genki Hatano, S. Kataura, Yasuhiro Banno, Y. Asai, Shigeyuki Suzuki","doi":"10.7600/jpfsm.9.247","DOIUrl":"https://doi.org/10.7600/jpfsm.9.247","url":null,"abstract":"Although static stretching is commonly performed to improve flexibility, it has been reported to have detrimental effects on muscle force and performance. Previous studies have reported that low-intensity and short-duration isometric contraction after static stretching inhibits stretch-induced force loss. However, the detailed effects of low-intensity short-duration isometric contraction after static stretching on flexibility, such as passive torque and stiffness, are currently unclear. Therefore, the current study sought to reveal the effects of low-intensity and short-duration isometric contraction after static stretching on flexibility and muscle force. Sixteen healthy participants (eight men, eight women) performed 300-s static stretching (SS), 300-s static stretching followed by 6-s 30% maximum isometric voluntary contraction (MIVC) (SS-30% MIVC), and 6-s 30% MIVC (30% MIVC) of the right hamstring on three separate days, in random order. Range of motion (ROM) and passive stiffness during knee extension, peak passive torque, and MIVC torque were obtained before and after exercise. ROM and peak passive torque were significantly increased after all exercises, whereas passive stiffness and MIVC torque were significantly decreased after SS only. Moreover, ROM after SS and SS-30% MIVC were significantly greater than that of 30% MIVC, and peak passive torque after SS-30% MIVC was significantly greater than that of SS, while passive stiffness after SS was significantly lower than that of 30% MIVC. These results indicate that low-intensity and short-duration isometric contraction after static stretching is effective for inhibiting stretch-induced force loss while also inhibiting the effects of static stretching on passive","PeriodicalId":55847,"journal":{"name":"Journal of Physical Fitness and Sports Medicine","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44359757","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Effects of combined therapy of ACE inhibitor and exercise on the development of diabetic nephropathy in Otsuka Long-Evans Tokushima fatty rats","authors":"Shinichiro Aoyama, Daisuke Shindo, Junichi Otsuka, Eriko Matsuo, Shigeru Matsubara, Masato Suzuki","doi":"10.7600/jpfsm.9.235","DOIUrl":"https://doi.org/10.7600/jpfsm.9.235","url":null,"abstract":"","PeriodicalId":55847,"journal":{"name":"Journal of Physical Fitness and Sports Medicine","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45777398","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Morifuji, Hidetoshi Nakao, Masashi Hashimoto, M. Imaoka, H. Fujino
Stretching exercises conducted by oneself, herein referred to as self-stretching exercises, improve arterial stiffness in healthy people. Such exercises include voluntary contraction of peripheral muscles in addition to stretching of target muscles. However, the effects of static passive stretching without voluntary contraction of skeletal muscles on arterial stiffness remain unknown. In addition, it is important to verify the effects of stretching in the elderly lacking exercise habits with advanced arterial stiffness. Therefore, the purpose of the present study was to verify the acute effects of static passive stretching, without voluntary contraction of skeletal muscles, on the cardio-ankle vascular index (CAVI) in elderly individuals lacking exercise habits. The present study followed a pretest-posttest design without a control group. Twenty-nine elderly individuals (mean age, 77.8 ± 7.0 years; 24 female) recruited at an orthopedic clinic participated in the present study. The participants were subjected to static passive stretching of the neck, trunk, and extremities for 40 min by the same physical thera-pist. Stretching involved the shoulder flexors/extensors, elbow flexors/extensors, wrist palmar flexors/dorsal flexors, hip flexors/extensors/adductors, knee flexors/extensors, ankle plantar flexors/dorsal flexors, neck muscles, and trunk muscles. The CAVI (Rt, Lt, Ave), ankle-brachial index (ABI), blood pressure, and pulse rate were assessed before and after stretching. After stretching, both CAVI (Lt, Ave) and pulse rate were significantly decreased. In contrast, no significant changes in CAVI (Rt), ABI, or blood pressure were observed. The key new finding of the present study was that static passive stretching without voluntary contraction of skeletal muscles acutely improved the CAVI in elderly individuals lacking exercise habits.
{"title":"Acute effects of static passive stretching without voluntary contraction of skeletal muscles on arterial stiffness in elderly lacking exercise habits","authors":"T. Morifuji, Hidetoshi Nakao, Masashi Hashimoto, M. Imaoka, H. Fujino","doi":"10.7600/jpfsm.9.217","DOIUrl":"https://doi.org/10.7600/jpfsm.9.217","url":null,"abstract":"Stretching exercises conducted by oneself, herein referred to as self-stretching exercises, improve arterial stiffness in healthy people. Such exercises include voluntary contraction of peripheral muscles in addition to stretching of target muscles. However, the effects of static passive stretching without voluntary contraction of skeletal muscles on arterial stiffness remain unknown. In addition, it is important to verify the effects of stretching in the elderly lacking exercise habits with advanced arterial stiffness. Therefore, the purpose of the present study was to verify the acute effects of static passive stretching, without voluntary contraction of skeletal muscles, on the cardio-ankle vascular index (CAVI) in elderly individuals lacking exercise habits. The present study followed a pretest-posttest design without a control group. Twenty-nine elderly individuals (mean age, 77.8 ± 7.0 years; 24 female) recruited at an orthopedic clinic participated in the present study. The participants were subjected to static passive stretching of the neck, trunk, and extremities for 40 min by the same physical thera-pist. Stretching involved the shoulder flexors/extensors, elbow flexors/extensors, wrist palmar flexors/dorsal flexors, hip flexors/extensors/adductors, knee flexors/extensors, ankle plantar flexors/dorsal flexors, neck muscles, and trunk muscles. The CAVI (Rt, Lt, Ave), ankle-brachial index (ABI), blood pressure, and pulse rate were assessed before and after stretching. After stretching, both CAVI (Lt, Ave) and pulse rate were significantly decreased. In contrast, no significant changes in CAVI (Rt), ABI, or blood pressure were observed. The key new finding of the present study was that static passive stretching without voluntary contraction of skeletal muscles acutely improved the CAVI in elderly individuals lacking exercise habits.","PeriodicalId":55847,"journal":{"name":"Journal of Physical Fitness and Sports Medicine","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48532428","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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