Urinary titin fragment concentration has been established as a noninvasive bio-marker of muscle protein degradation and muscle damage after exercise. We hypothesized that concerning the microdamage in the chronic phase of muscle strain injury, muscle damage is more likely to occur after exposure to training workload. We aimed to evaluate the urinary titin fragment concentration in professional soccer players who previously had muscle strain injuries (injured vs uninjured group: mean ± SEM age [years], 26.25 ± 1.4 vs 23.75 ± 1.01; playing years, 14.375 ± 1.17 vs 12.25 ± 0.24; height [cm], 173.63 ± 1.98 vs 176.38 ± 1.0; weight [kg], 69.63 ± 2.05 vs 72.38 ± 1.87; mean body mass index [kg/m 2 ], 23.0 ± 0.32 vs 23.25 ± 1.39). The urine titin N-terminal fragments of eight professional soccer players with a previous muscle strain and eight uninjured players were measured using enzyme-linked immunosorbent assay before and 12 h after general team training. The urinary titin fragment values before and after training and the change in the titin fragment-to-creatinine fragment ratio were compared between the groups. The initial urinary titin fragment value did not significantly differ between the injured (from 18,457.96 ± 3,615.54 to 115,480.29 ± 26,462.36) and uninjured groups (from 23,119.47 ± 8,107.72 to 46,206.32 ± 9,833.77); however, the urine titin fragment value and change in the changes in urinary titin fragment ratio from before to after training were higher in the injured group (Wilcoxon rank-sum test, p < 0.05). These findings may help guide the future management of athletes with previous muscle strain injuries. Urine titin fragment values could be used to evaluate athletes with previous muscle injury.
尿中titin片段浓度已被确定为运动后肌肉蛋白降解和肌肉损伤的非侵入性生物标志物。我们假设，关于肌肉劳损慢性期的微损伤，暴露于训练负荷后更有可能发生肌肉损伤。我们旨在评估曾有肌肉拉伤的职业足球运动员（受伤组与未受伤组：平均±SEM年龄[年]，26.25±1.4 vs 23.75±1.01；比赛年龄，14.375±1.17 vs 12.25±0.24；身高[cm]，173.63±1.98 vs 176.38±1.0；体重[kg]，69.63±2.05 vs 72.38±1.87；平均体重指数[kg/m2]分别为23.0±0.32vs23.25±1.39）。采用酶联免疫吸附法测定了8名有肌肉拉伤史的职业足球运动员和8名未受伤运动员在常规团队训练前和训练后12h的尿titin N-末端片段。比较两组训练前后的尿titin片段值以及titin片段与肌酸酐片段比率的变化。损伤组（18457.96±3615.54至115480.29±26462.36）和未损伤组（23119.47±8107.72至46206.32±9833.77）的初始尿中titin片段值无显著差异；但损伤组训练前后尿中titin片段值和尿中titin-片段比值的变化均较高（Wilcoxon秩和检验，p<0.05），这些发现可能有助于指导既往肌肉劳损运动员的治疗。尿titin片段值可用于评估有肌肉损伤史的运动员。
{"title":"Post-training urinary titin fragment concentration increases in athletes with previous muscle strain injury: a pilot study in soccer players","authors":"Tomonori Kawai, Koichi Takamoto, Itsumu Bito","doi":"10.7600/jpfsm.10.263","DOIUrl":"https://doi.org/10.7600/jpfsm.10.263","url":null,"abstract":"Urinary titin fragment concentration has been established as a noninvasive bio-marker of muscle protein degradation and muscle damage after exercise. We hypothesized that concerning the microdamage in the chronic phase of muscle strain injury, muscle damage is more likely to occur after exposure to training workload. We aimed to evaluate the urinary titin fragment concentration in professional soccer players who previously had muscle strain injuries (injured vs uninjured group: mean ± SEM age [years], 26.25 ± 1.4 vs 23.75 ± 1.01; playing years, 14.375 ± 1.17 vs 12.25 ± 0.24; height [cm], 173.63 ± 1.98 vs 176.38 ± 1.0; weight [kg], 69.63 ± 2.05 vs 72.38 ± 1.87; mean body mass index [kg/m 2 ], 23.0 ± 0.32 vs 23.25 ± 1.39). The urine titin N-terminal fragments of eight professional soccer players with a previous muscle strain and eight uninjured players were measured using enzyme-linked immunosorbent assay before and 12 h after general team training. The urinary titin fragment values before and after training and the change in the titin fragment-to-creatinine fragment ratio were compared between the groups. The initial urinary titin fragment value did not significantly differ between the injured (from 18,457.96 ± 3,615.54 to 115,480.29 ± 26,462.36) and uninjured groups (from 23,119.47 ± 8,107.72 to 46,206.32 ± 9,833.77); however, the urine titin fragment value and change in the changes in urinary titin fragment ratio from before to after training were higher in the injured group (Wilcoxon rank-sum test, p < 0.05). These findings may help guide the future management of athletes with previous muscle strain injuries. Urine titin fragment values could be used to evaluate athletes with previous muscle injury.","PeriodicalId":55847,"journal":{"name":"Journal of Physical Fitness and Sports Medicine","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43168009","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}
Ryota Tejima, Yasushi Fukuda, T. Yamaguchi, K. Koyama
Studies have shown that soccer players have a high prevalence of low back pain (LBP). However, physical characteristics (sagittal spinal alignment and hip joint range of motion [ROM]) associated with LBP have not been clarified. This study seeks to clarify the relationship between physical characteristics and LBP in high school male soccer players. The participants were 90 high school male soccer players. The presence of LBP was evaluated using a questionnaire. We assigned the participants into two groups: the non-LBP group (n = 58) and the LBP group (n = 32). Passive ROM of hip and sagittal spinal alignment were measured. Thoracic kyphotic angle (TKA) was significantly higher in the LBP group than in the non-LBP group, and the ROM of hip joint extension in the nondominant leg was significantly lower in the LBP group than in the non-LBP group. On logistic regression analyses, TKA in the upright position (adjusted odds ratio [OR]: 1.087, 95% confidence interval [CI]: 1.019–1.159, p < 0.01) and hip extension ROM deficits in the nondominant leg (adjusted OR: 0.888, 95% CI: 0.789– 0.999, p < 0.05) were related to LBP in high school male soccer players as determined. This study suggests that hyperkyphosis in the upright position and hip extension ROM deficits in the nondominant leg were related to LBP in high school male soccer players.
{"title":"Relation between low back pain and physical characteristics in high school male soccer players","authors":"Ryota Tejima, Yasushi Fukuda, T. Yamaguchi, K. Koyama","doi":"10.7600/jpfsm.10.225","DOIUrl":"https://doi.org/10.7600/jpfsm.10.225","url":null,"abstract":"Studies have shown that soccer players have a high prevalence of low back pain (LBP). However, physical characteristics (sagittal spinal alignment and hip joint range of motion [ROM]) associated with LBP have not been clarified. This study seeks to clarify the relationship between physical characteristics and LBP in high school male soccer players. The participants were 90 high school male soccer players. The presence of LBP was evaluated using a questionnaire. We assigned the participants into two groups: the non-LBP group (n = 58) and the LBP group (n = 32). Passive ROM of hip and sagittal spinal alignment were measured. Thoracic kyphotic angle (TKA) was significantly higher in the LBP group than in the non-LBP group, and the ROM of hip joint extension in the nondominant leg was significantly lower in the LBP group than in the non-LBP group. On logistic regression analyses, TKA in the upright position (adjusted odds ratio [OR]: 1.087, 95% confidence interval [CI]: 1.019–1.159, p < 0.01) and hip extension ROM deficits in the nondominant leg (adjusted OR: 0.888, 95% CI: 0.789– 0.999, p < 0.05) were related to LBP in high school male soccer players as determined. This study suggests that hyperkyphosis in the upright position and hip extension ROM deficits in the nondominant leg were related to LBP in high school male soccer players.","PeriodicalId":55847,"journal":{"name":"Journal of Physical Fitness and Sports Medicine","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41818446","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 the present study, we examined the biological maturity of young Japanese football players. In Japan’s football training system, players are selected at a young age. However, relatively early maturing players might be selected if the selection is based solely on technical and physical fitness factors. To eliminate this drawback in player selection, we believe that it is necessary to determine the players’ biological maturity accurately. Accordingly, the present study aimed to investigate the biological maturity of football players during the selection process. We included 475 young Japanese football players (mean age: 12.4 ± 0.6 years) affiliated with the Japan Professional Football League between 2007 and 2015. According to an unpaired t-test, there was no significant difference between the Tanner-Whitehouse 2 (Japan) skeletal age and the chronological age of the affiliated players. The difference in biological maturity between the junior youth (Jy) group (mean age: 12.9 ± 0.4 years [12.0–13.9]) and the junior (Jr) group (mean age: 11.8 ± 0.3 years [11.0–12.4]) was examined using a chi-squared test. The results of the residual analysis revealed a significant difference between the Jy and Jr groups ( χ 2 = 22.552, degree of freedom = 3, p < 0.01). We evaluated the biological maturity of young football players and examined the relationship between the differences in maturity and the timing of player selection. In the player selection process in this study, it was speculated that early maturing players may not always be easy to identify.
{"title":"Selection time and differences in biological maturity of soccer players in Japan Professional Football League Academy","authors":"R. Takahara, S. Miyakawa","doi":"10.7600/jpfsm.10.269","DOIUrl":"https://doi.org/10.7600/jpfsm.10.269","url":null,"abstract":"In the present study, we examined the biological maturity of young Japanese football players. In Japan’s football training system, players are selected at a young age. However, relatively early maturing players might be selected if the selection is based solely on technical and physical fitness factors. To eliminate this drawback in player selection, we believe that it is necessary to determine the players’ biological maturity accurately. Accordingly, the present study aimed to investigate the biological maturity of football players during the selection process. We included 475 young Japanese football players (mean age: 12.4 ± 0.6 years) affiliated with the Japan Professional Football League between 2007 and 2015. According to an unpaired t-test, there was no significant difference between the Tanner-Whitehouse 2 (Japan) skeletal age and the chronological age of the affiliated players. The difference in biological maturity between the junior youth (Jy) group (mean age: 12.9 ± 0.4 years [12.0–13.9]) and the junior (Jr) group (mean age: 11.8 ± 0.3 years [11.0–12.4]) was examined using a chi-squared test. The results of the residual analysis revealed a significant difference between the Jy and Jr groups ( χ 2 = 22.552, degree of freedom = 3, p < 0.01). We evaluated the biological maturity of young football players and examined the relationship between the differences in maturity and the timing of player selection. In the player selection process in this study, it was speculated that early maturing players may not always be easy to identify.","PeriodicalId":55847,"journal":{"name":"Journal of Physical Fitness and Sports Medicine","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45637458","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 aim of the present study was to clarify the factors affecting an increase in core body temperature during 40°C water immersion to the subclavian level. Fifteen healthy males were immersed in water for 60 min. Rectal temperature (T rec ) and skin temperature (T sk ) at four skin sites were determined. Minute ventilation (V ・ E ) was measured, and metabolic rate was determined by indirect calorimetry. Skin blood flow and sweat rate at the forehead were assessed using laser-Doppler flowmetry (%LDF head ) and dew hygrometry (SR head ), respectively. Hot feeling was assessed with a visual analog scale. When T rec reached 39°C or participants reported an extremely hot feeling, the experiment was ceased. Eleven participants were unable to complete the protocol (ten participants due to T rec > 39°C; and one due to excessive hot feeling). T rec increased with immersion period. Mean T sk was unchanged from 20 min. V ・ E and metabolic rate increased with immersion period. %LDF head and SR head increased after immersion and remained unchanged from 15 and 30 min, respectively. Change in T rec from the baseline at 15, 30, and 45 min was correlated to cumulative change in metabolic rate from the baseline at 0-15, 0-30, and 0-45 min. No correlations were observed between change in T rec and cumulative changes in V ・ E , %LDF head , and SR head from baseline, hot feeling, body weight and body composition. Water immersion at 40°C induced a large difference in the increase of T rec , in which metabolic responses to heat stress may be involved. The relationship between heat tolerance and change in T rec is different among individuals.
{"title":"Factors affecting an increase in core body temperature and heat tolerance during hot water immersion","authors":"Yuta Masuda, I. Kato, K. Nagashima","doi":"10.7600/jpfsm.10.243","DOIUrl":"https://doi.org/10.7600/jpfsm.10.243","url":null,"abstract":"The aim of the present study was to clarify the factors affecting an increase in core body temperature during 40°C water immersion to the subclavian level. Fifteen healthy males were immersed in water for 60 min. Rectal temperature (T rec ) and skin temperature (T sk ) at four skin sites were determined. Minute ventilation (V ・ E ) was measured, and metabolic rate was determined by indirect calorimetry. Skin blood flow and sweat rate at the forehead were assessed using laser-Doppler flowmetry (%LDF head ) and dew hygrometry (SR head ), respectively. Hot feeling was assessed with a visual analog scale. When T rec reached 39°C or participants reported an extremely hot feeling, the experiment was ceased. Eleven participants were unable to complete the protocol (ten participants due to T rec > 39°C; and one due to excessive hot feeling). T rec increased with immersion period. Mean T sk was unchanged from 20 min. V ・ E and metabolic rate increased with immersion period. %LDF head and SR head increased after immersion and remained unchanged from 15 and 30 min, respectively. Change in T rec from the baseline at 15, 30, and 45 min was correlated to cumulative change in metabolic rate from the baseline at 0-15, 0-30, and 0-45 min. No correlations were observed between change in T rec and cumulative changes in V ・ E , %LDF head , and SR head from baseline, hot feeling, body weight and body composition. Water immersion at 40°C induced a large difference in the increase of T rec , in which metabolic responses to heat stress may be involved. The relationship between heat tolerance and change in T rec is different among individuals.","PeriodicalId":55847,"journal":{"name":"Journal of Physical Fitness and Sports Medicine","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42693198","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 relationship between electromyographic (EMG) amplitude and exerted force has been established in numerous studies and used as fundamental knowledge to interpret the results of EMG in human movement. Recent neuroanatomical studies suggest that the individual hamstring muscles may be regionally regulated by the central nervous system. In fact, a few studies observed nonuniform EMG activities between regions along the length of the biceps femoris long head (BFlh) and semitendinosus (ST) during knee flexion exercise. However, it remains unknown whether the EMG-force relationship varies among regions of the individual hamstring muscles. This study aimed to compare the EMG-force relationship among regions of the individual hamstring muscles during knee flexion exercise. Thirteen healthy males performed isometric knee flexion at 20%–80% of maximal voluntary contraction (MVC). Surface EMG amplitudes in the proximal, middle, and distal regions of the biceps femoris long head, semitendinosus, and semimembranosus (SM) were assessed and normalized to the root mean square (RMS) during MVC as %RMS. The results showed that %RMS of BFlh was consistently higher in the distal regions than in the proximal region at 20%–80% of MVC (all: p < 0.05). In ST, %RMS in the middle and distal regions were higher than that in the proximal regions only at 20% of MVC ( p < 0.05). Similarly, %RMS of SM was higher in the middle region than in the proximal region at 20% and 40% of MVC (all: p < 0.05). These results suggest that the EMG-force relationship is not consistent among regions of the individual hamstring muscles, especially between the proximal and distal regions of BFlh.
{"title":"Regional difference in the EMG-force relationship of the hamstring muscles during knee flexion","authors":"Raki Kawama, Hirohiko Maemura, S. Tanigawa","doi":"10.7600/jpfsm.10.233","DOIUrl":"https://doi.org/10.7600/jpfsm.10.233","url":null,"abstract":"The relationship between electromyographic (EMG) amplitude and exerted force has been established in numerous studies and used as fundamental knowledge to interpret the results of EMG in human movement. Recent neuroanatomical studies suggest that the individual hamstring muscles may be regionally regulated by the central nervous system. In fact, a few studies observed nonuniform EMG activities between regions along the length of the biceps femoris long head (BFlh) and semitendinosus (ST) during knee flexion exercise. However, it remains unknown whether the EMG-force relationship varies among regions of the individual hamstring muscles. This study aimed to compare the EMG-force relationship among regions of the individual hamstring muscles during knee flexion exercise. Thirteen healthy males performed isometric knee flexion at 20%–80% of maximal voluntary contraction (MVC). Surface EMG amplitudes in the proximal, middle, and distal regions of the biceps femoris long head, semitendinosus, and semimembranosus (SM) were assessed and normalized to the root mean square (RMS) during MVC as %RMS. The results showed that %RMS of BFlh was consistently higher in the distal regions than in the proximal region at 20%–80% of MVC (all: p < 0.05). In ST, %RMS in the middle and distal regions were higher than that in the proximal regions only at 20% of MVC ( p < 0.05). Similarly, %RMS of SM was higher in the middle region than in the proximal region at 20% and 40% of MVC (all: p < 0.05). These results suggest that the EMG-force relationship is not consistent among regions of the individual hamstring muscles, especially between the proximal and distal regions of BFlh.","PeriodicalId":55847,"journal":{"name":"Journal of Physical Fitness and Sports Medicine","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44670782","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}
Satoru Nishida, S. Kunugi, K. Maehara, S. Miyakawa
Larger hip flexion range of motion with knee extension (hip flexion ROM) and passive stiffness of the hamstring is associated with greater production of isometric and concentric knee flexion torque at longer muscle lengths. Nevertheless, associations among hip flexion ROM, passive stiffness of hamstring, and eccentric knee flexion torque at a longer muscle length remain unclear. Therefore, we aimed to investigate the association among hip flexion ROM, passive stiffness of hamstring and eccentric knee flexion angle-torque relationship. Seventeen healthy male college students participated in this study, and all measurements were performed on both legs (34 legs). No participants had any previous hamstring strain injury. Hip flexion ROM, passive stiffness of hamstring, peak torque and peak torque angle during isokinetic eccentric knee flexion were measured. The correlation among the variables of interest were assessed. Passive stiffness of hamstring and eccentric peak knee flexion torque negatively correlated with the peak torque angle ( r = −0.39). On the other hand, peak torque angle was not correlated with hip flexion ROM ( r = 0.08). The present study revealed that higher passive stiffness of hamstring was associated with greater production of eccentric knee flexion torque at longer muscle lengths.
{"title":"Association between passive stiffness of hamstring and eccentric knee flexion angle-torque relationship","authors":"Satoru Nishida, S. Kunugi, K. Maehara, S. Miyakawa","doi":"10.7600/JPFSM.10.205","DOIUrl":"https://doi.org/10.7600/JPFSM.10.205","url":null,"abstract":"Larger hip flexion range of motion with knee extension (hip flexion ROM) and passive stiffness of the hamstring is associated with greater production of isometric and concentric knee flexion torque at longer muscle lengths. Nevertheless, associations among hip flexion ROM, passive stiffness of hamstring, and eccentric knee flexion torque at a longer muscle length remain unclear. Therefore, we aimed to investigate the association among hip flexion ROM, passive stiffness of hamstring and eccentric knee flexion angle-torque relationship. Seventeen healthy male college students participated in this study, and all measurements were performed on both legs (34 legs). No participants had any previous hamstring strain injury. Hip flexion ROM, passive stiffness of hamstring, peak torque and peak torque angle during isokinetic eccentric knee flexion were measured. The correlation among the variables of interest were assessed. Passive stiffness of hamstring and eccentric peak knee flexion torque negatively correlated with the peak torque angle ( r = −0.39). On the other hand, peak torque angle was not correlated with hip flexion ROM ( r = 0.08). The present study revealed that higher passive stiffness of hamstring was associated with greater production of eccentric knee flexion torque at longer muscle lengths.","PeriodicalId":55847,"journal":{"name":"Journal of Physical Fitness and Sports Medicine","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41648902","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}
Taisei Hakozaki, Shota Enoki, Seiya Sakihama, Soju Ishimatsu, R. Kuramochi
Subconcussive head impact exposure in sports is a complex public health issue. Although many head impacts are asymptomatic, the near point of convergence (NPC) that measures the closest point of focus before diplopia occurs, has been shown to reflect subclini-cal neuronal damage. Studies have not been conducted on the effect of repeated head impact exposure due to falls from heights, like in pole vaulting. This study examines the NPC response in collegiate pole vaulters with indirect head impact history due to falls from heights. This prospective observational study included four-pole vaulters and three decathletes. The study was conducted during the end of the Japanese collegiate track and field season. The measurements were taken at pre-practice, 0 h post-practice, 24 h post-practice, 1 week post-practice, 2 weeks post-practice, 3 weeks post-practice, and 4 weeks post-practice. Players completed the NPC test and the symptom checklist. There was a significant difference in the NPC value at pre-practice and 4 weeks post-practice; P = 0.048. Compared to pre-practice values, NPC significantly increased at 0 h post-practice (mean [SE] values: pre-practice, 5.61 [0.69] cm; 0 h post-practice, 7.31 [0.79] cm; P = 0.02). At 3 weeks post-practice and 4 weeks post-practice, NPC values were significantly reduced compared to the values at 0 h post-practice (mean [SE] values: 0 h post-practice, 7.31 [0.79] cm; 3 weeks post-practice, 5.75 [0.61] cm; 4 weeks post-practice, 5.52 [0.64] cm). This study reveals that NPC can be impaired by pole vaulting. The increased NPC returned to normal after 3 - 4 weeks of rest. This study is a prospective observational study of collegiate pole vaulters with the goal of testing the hypothesis that NPC would be significantly worsened due to repetitive head impact incidents as a result of falls from excessive height. We further aimed to examine the duration required for increased NPC values to return to baseline levels.
体育运动中的头部撞击暴露是一个复杂的公共卫生问题。尽管许多头部撞击是无症状的，但在复视发生前测量最近焦点的近会聚点（NPC）已被证明反映了亚临床神经元损伤。尚未对高空坠落（如撑杆跳高）造成的反复头部撞击的影响进行研究。本研究考察了因高空坠落而有间接头部撞击史的大学生撑杆跳高运动员的NPC反应。这项前瞻性观察研究包括四名撑杆跳高运动员和三名十项全能运动员。这项研究是在日本大学田径赛季结束时进行的。测量在练习前、练习后0小时、练习后24小时、练习前1周、练习后2周、练习前3周和练习后4周进行。玩家完成了NPC测试和症状检查表。训练前和训练后4周的NPC值有显著差异；P＝0.048。与练习前相比，NPC在练习后0小时显著增加（平均[SE]值：练习前5.61[0.69]cm；练习后0 h 7.31[0.79]cm；P=0.02），与训练后0小时的数值相比，NPC数值显著降低（平均[SE]数值：训练后0 h，7.31[0.79]cm；训练后3周，5.75[0.61]cm；练习后4周，5.52[0.64]cm）。这项研究揭示了撑杆跳对NPC的影响。休息3-4周后，增加的NPC恢复正常。这项研究是一项针对大学撑杆跳高运动员的前瞻性观察研究，目的是检验以下假设：由于从过高的高度跌落导致重复性头部撞击事件，NPC会显著恶化。我们进一步旨在检查NPC值增加恢复到基线水平所需的持续时间。
{"title":"Oculomotor response in male collegiate pole vaulters after repeated head impact due to falls from heights: a pilot longitudinal study","authors":"Taisei Hakozaki, Shota Enoki, Seiya Sakihama, Soju Ishimatsu, R. Kuramochi","doi":"10.7600/JPFSM.10.213","DOIUrl":"https://doi.org/10.7600/JPFSM.10.213","url":null,"abstract":"Subconcussive head impact exposure in sports is a complex public health issue. Although many head impacts are asymptomatic, the near point of convergence (NPC) that measures the closest point of focus before diplopia occurs, has been shown to reflect subclini-cal neuronal damage. Studies have not been conducted on the effect of repeated head impact exposure due to falls from heights, like in pole vaulting. This study examines the NPC response in collegiate pole vaulters with indirect head impact history due to falls from heights. This prospective observational study included four-pole vaulters and three decathletes. The study was conducted during the end of the Japanese collegiate track and field season. The measurements were taken at pre-practice, 0 h post-practice, 24 h post-practice, 1 week post-practice, 2 weeks post-practice, 3 weeks post-practice, and 4 weeks post-practice. Players completed the NPC test and the symptom checklist. There was a significant difference in the NPC value at pre-practice and 4 weeks post-practice; P = 0.048. Compared to pre-practice values, NPC significantly increased at 0 h post-practice (mean [SE] values: pre-practice, 5.61 [0.69] cm; 0 h post-practice, 7.31 [0.79] cm; P = 0.02). At 3 weeks post-practice and 4 weeks post-practice, NPC values were significantly reduced compared to the values at 0 h post-practice (mean [SE] values: 0 h post-practice, 7.31 [0.79] cm; 3 weeks post-practice, 5.75 [0.61] cm; 4 weeks post-practice, 5.52 [0.64] cm). This study reveals that NPC can be impaired by pole vaulting. The increased NPC returned to normal after 3 - 4 weeks of rest. This study is a prospective observational study of collegiate pole vaulters with the goal of testing the hypothesis that NPC would be significantly worsened due to repetitive head impact incidents as a result of falls from excessive height. We further aimed to examine the duration required for increased NPC values to return to baseline levels.","PeriodicalId":55847,"journal":{"name":"Journal of Physical Fitness and Sports Medicine","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45009182","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}
Yukiya Tanoue, T. Komiyama, Hiroaki Tanaka, Y. Higaki, Y. Uehara
After exercise training, improvement in cognitive function is associated with high parasympathetic nervous activity. However, the relationship between cardiac autonomic nervous activity and cognitive function after acute exercise may differ from that after chronic exercise, because parasympathetic nervous activity decreases with acute exercise. Here, we examined the relationship between parasympathetic nervous activity and cognitive function after acute exercise. Twelve male participants performed cognitive tasks in exercise and non-exercise conditions, with a randomized crossover design. Participants in the exercise condition ran on a treadmill for 10 min, with a running speed corresponding to a rate of perceived exertion (RPE) of 10–12 in each subject. Cognitive tasks were performed before and after both conditions. Heart rate variability during cognitive tasks was measured to evaluate autonomic nervous system activity. In the exercise condition, RPE was 11.1 ± 0.2 (mean ± SE) immediately after exercise. Exercise at RPE 10–12 improved reaction times in Go trials (from 687.8 ± 55.2 to 568.2 ± 45.9 ms, P < 0.05). In the non-exercise condition, cognitive performance remained stable throughout the experiment. In addition, parasympathetic nervous activity (high-frequency component of heart rate variability) remained low after exercise compared with before exercise (from 586.4 ± 122.5 to 372.8 ± 92.9 ms 2 , P < 0.05). In contrast, parasympathetic nervous activity increased in the non-exercise condition (from 516.6 ± 94.9 ms 2 to 642.5 ± 85.6 ms 2 , P < 0.05). The present results suggest that improvement in cognitive function after acute exercise may be related to reduced parasympathetic nervous activity.
{"title":"Relationship between cognitive function and parasympathetic nerve activity after acute mild to moderate intensity exercise","authors":"Yukiya Tanoue, T. Komiyama, Hiroaki Tanaka, Y. Higaki, Y. Uehara","doi":"10.7600/jpfsm.10.181","DOIUrl":"https://doi.org/10.7600/jpfsm.10.181","url":null,"abstract":"After exercise training, improvement in cognitive function is associated with high parasympathetic nervous activity. However, the relationship between cardiac autonomic nervous activity and cognitive function after acute exercise may differ from that after chronic exercise, because parasympathetic nervous activity decreases with acute exercise. Here, we examined the relationship between parasympathetic nervous activity and cognitive function after acute exercise. Twelve male participants performed cognitive tasks in exercise and non-exercise conditions, with a randomized crossover design. Participants in the exercise condition ran on a treadmill for 10 min, with a running speed corresponding to a rate of perceived exertion (RPE) of 10–12 in each subject. Cognitive tasks were performed before and after both conditions. Heart rate variability during cognitive tasks was measured to evaluate autonomic nervous system activity. In the exercise condition, RPE was 11.1 ± 0.2 (mean ± SE) immediately after exercise. Exercise at RPE 10–12 improved reaction times in Go trials (from 687.8 ± 55.2 to 568.2 ± 45.9 ms, P < 0.05). In the non-exercise condition, cognitive performance remained stable throughout the experiment. In addition, parasympathetic nervous activity (high-frequency component of heart rate variability) remained low after exercise compared with before exercise (from 586.4 ± 122.5 to 372.8 ± 92.9 ms 2 , P < 0.05). In contrast, parasympathetic nervous activity increased in the non-exercise condition (from 516.6 ± 94.9 ms 2 to 642.5 ± 85.6 ms 2 , P < 0.05). The present results suggest that improvement in cognitive function after acute exercise may be related to reduced parasympathetic nervous activity.","PeriodicalId":55847,"journal":{"name":"Journal of Physical Fitness and Sports Medicine","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45011997","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}
Precise and sequential motor tasks that require strenuous and fine force control involve distinct, complex neural mechanisms without which they would be difficult to perform. A previous study showed that strenuous force exertion gives rise to potentiation of active muscles (post-contraction potentiation, PCP). However, the mechanisms underlying PCP remain unclear. We investigated the neural mechanisms underlying PCP using spectral analyses of surface EMG activity. Fourteen healthy participants were asked to perform an EMG matching task (2% of maximum voluntary contraction, MVC) before (Test 1) and after (Test 2) they exerted a brief 50% MVC (conditioning contraction, CC). The exerted force was significantly lower during Test 2 than Test 1, indicating that PCP did occur. In addition, spike-like EMG responses with a mean frequency of ~10 Hz were frequently observed during Test 2. Power spectrum analysis demonstrated that the peak power of both α and β bands increased after CC, and that changes in the peak power of both bands during Test 2 negatively correlated with changes in force. These findings suggest that the synchronization of active motor units accounted for PCP.
{"title":"Possible neural mechanisms underlying post-contraction potentiation in elbow flexor muscle in humans","authors":"Tomoya Ishii, S. Sasada, T. Komiyama","doi":"10.7600/JPFSM.10.171","DOIUrl":"https://doi.org/10.7600/JPFSM.10.171","url":null,"abstract":"Precise and sequential motor tasks that require strenuous and fine force control involve distinct, complex neural mechanisms without which they would be difficult to perform. A previous study showed that strenuous force exertion gives rise to potentiation of active muscles (post-contraction potentiation, PCP). However, the mechanisms underlying PCP remain unclear. We investigated the neural mechanisms underlying PCP using spectral analyses of surface EMG activity. Fourteen healthy participants were asked to perform an EMG matching task (2% of maximum voluntary contraction, MVC) before (Test 1) and after (Test 2) they exerted a brief 50% MVC (conditioning contraction, CC). The exerted force was significantly lower during Test 2 than Test 1, indicating that PCP did occur. In addition, spike-like EMG responses with a mean frequency of ~10 Hz were frequently observed during Test 2. Power spectrum analysis demonstrated that the peak power of both α and β bands increased after CC, and that changes in the peak power of both bands during Test 2 negatively correlated with changes in force. These findings suggest that the synchronization of active motor units accounted for PCP.","PeriodicalId":55847,"journal":{"name":"Journal of Physical Fitness and Sports Medicine","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43347040","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}
Jumpei Takahashi, H. Suzuki, Naoki Tanaka, Toru Nishiyama
Bridge exercises help strengthen the muscles of the lower limbs and trunk. Previous studies have examined muscle activity during bridge exercises using balance balls and balance mats during which the body’s balance is only partially disturbed. However, no study has examined muscle activity during bridge exercises when performed on an air mattress, during which the entire body is not balanced. Therefore, the purpose of this study was to verify the differences in muscle activity during bridge exercises when performed on a hard surface like a platform or on an air mattress. Twenty-four healthy university students were instructed to perform bridge exercises using three different knee joint angles (90°, 110°, 130°) and two different types of floor surfaces. Muscle activity of the erector spinae, gluteus maximus and lateral hamstrings was measured by using a surface electromyograph, Each muscle showed significantly higher levels of muscle activity during certain knee joint angle conditions when performed on an air mat (p < 0.05). In the erector spinae, muscle activity at 90° was significantly higher than at 130° of the knee joint in the air mattress condition. For the gluteus maximus, there were no significant differences among the angles of the knee joint. The results of this study show that muscle activity while performing bridge exercises increases when the entire body is placed on a soft surface.
{"title":"Muscle activity during bridge exercises on different types of floor surfaces","authors":"Jumpei Takahashi, H. Suzuki, Naoki Tanaka, Toru Nishiyama","doi":"10.7600/JPFSM.10.199","DOIUrl":"https://doi.org/10.7600/JPFSM.10.199","url":null,"abstract":"Bridge exercises help strengthen the muscles of the lower limbs and trunk. Previous studies have examined muscle activity during bridge exercises using balance balls and balance mats during which the body’s balance is only partially disturbed. However, no study has examined muscle activity during bridge exercises when performed on an air mattress, during which the entire body is not balanced. Therefore, the purpose of this study was to verify the differences in muscle activity during bridge exercises when performed on a hard surface like a platform or on an air mattress. Twenty-four healthy university students were instructed to perform bridge exercises using three different knee joint angles (90°, 110°, 130°) and two different types of floor surfaces. Muscle activity of the erector spinae, gluteus maximus and lateral hamstrings was measured by using a surface electromyograph, Each muscle showed significantly higher levels of muscle activity during certain knee joint angle conditions when performed on an air mat (p < 0.05). In the erector spinae, muscle activity at 90° was significantly higher than at 130° of the knee joint in the air mattress condition. For the gluteus maximus, there were no significant differences among the angles of the knee joint. The results of this study show that muscle activity while performing bridge exercises increases when the entire body is placed on a soft surface.","PeriodicalId":55847,"journal":{"name":"Journal of Physical Fitness and Sports Medicine","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41274062","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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