Current Issue : January - March Volume : 2015 Issue Number : 1 Articles : 5 Articles
Background: Despite growing interest in the relationship between exercise and short-term neural plasticity, the\neffects of exercise on motor cortical (M1) excitability are not well studied. Acute, lower-limb aerobic exercise may\npotentially modulate M1 excitability in working muscles, but the effects on muscles not involved in the exercise are\nunknown. Here we examined the excitability changes in an upper limb muscle representation following a single\nsession of lower body aerobic exercise. Investigating the response to exercise in a non-exercised muscle may help\nto determine the clinical usefulness of lower-body exercise interventions for upper limb neurorehabilitation.\nMethods: In this study, transcranial magnetic stimulation was used to assess inputââ?¬â??output curves, short-interval\nintracortical inhibition (SICI), long-interval intracortical inhibition (LICI) and intracortical facilitation (ICF) in the\nextensor carpi radialis muscle in twelve healthy individuals following a single session of moderate stationary biking.\nAdditionally, we examined whether the presence of a common polymorphism of the brain-derived neurotrophic\nfactor (BDNF) gene would affect the response of these measures to exercise.\nResults: We observed significant increases in ICF and decreases in SICI following exercise. No changes in LICI were\ndetected, and no differences were observed in inputââ?¬â??output curves following exercise, or between BDNF groups.\nConclusions: The current results demonstrate that the modulation of intracortical excitability following aerobic\nexercise is not limited to those muscles involved in the exercise, and that while exercise does not directly modulate\nthe excitability of motor neurons, it may facilitate the induction of experience-dependent plasticity via a decrease in\nintracortical inhibition and increase in intracortical facilitation. These findings indicate that exercise may create\nfavourable conditions for adaptive plasticity in M1 and may be an effective adjunct to traditional training or\nrehabilitation methods....
Background: This study investigated swimming speeds and sex differences of finalists competing at the Olympic\nGames (i.e. 624 female and 672 male athletes) and FINA World Championships (i.e. 990 women and 1008 men)\nbetween 1992 and 2013.\nMethods: Linear, non-linear and multi-level regression models were used to investigate changes in swimming\nspeeds and sex differences for champions and finalists.\nResults: Regarding finalists in FINA World Championships and Olympic Games, swimming speed increased linearly\nin both women and men in all disciplines and race distances. Male world champions� swimming speed remained\nstable in 200 m butterfly, 400 m, 800 m and 1,500 m freestyle. Considering women, swimming speed remained\nunchanged in 50 m and 400 m freestyle. In the Olympic Games, swimming speed of male champions remained\nunchanged in 200 m breaststroke, 50 m, 400 m, 800 m and 1,500 m freestyle. Female Olympic champions�\nswimming speed remained stable in 100 m and 200 m backstroke, 100 m butterfly, 200 m individual medley, 50 m\nand 200 m freestyle. Evaluating sex differences between finalists in FINA World Championships, results showed a\nlinear decrease in 100 m breaststroke and 200 m butterfly and a non-linear increase in 100 m backstroke. In finals\nat the Olympic Games, the sex difference decreased linearly for 100 m backstroke, 400 m and 800 m freestyle.\nHowever, a linear increase for 200 m butterfly can be reported. Considering Olympic and world champions, the sex\ndifference remained stable in all disciplines and race distances.\nConclusion: Swimming speed of the finalists at the Olympic Games and FINA World Championships increased\nlinearly. The top annual female swimmers increased swimming speed rather at longer race distances (i.e. 800 m and\n1,500 m freestyle, 200 m butterfly, and 400 m individual medley), whereas the top annual male swimmers increased\nit rather at shorter race distances (i.e. 100 m and 200 m freestyle, 100 m butterfly, and 100 m breaststroke). Sex\ndifference in swimming was unchanged in Olympic and world champions. Finalists and champions at the Olympic\nGames and FINA World Championships reduced the sex difference with increasing race distance....
Background: The hemodynamic and cardiac responses to exercise have been widely investigated in adults.\nHowever, little is known regarding myocardial performance in response to a short bout of maximal exercise in\nadolescents. We therefore sought to study alterations in myocardial function and investigate sex-influences in\nyoung athletes after maximal cardiopulmonary testing.\nMethods: 51 adolescent (13-19 years old) floor-ball players (24 females) were recruited. All subjects underwent a\nmaximal exercise test to determine maximal oxygen uptake (VO2max) and cardiac output. Cardiac performance was\ninvestigated using conventional and tissue velocity imaging, as well as 2D strain echocardiography before and\n30 minutes following exercise. Arterio-ventricular coupling was evaluated by means of single beat ventricular elastance\nand arterial elastance.\nResults: Compared to baseline the early diastolic myocardial velocity (E?LV) at the basal left ventricular (LV) segments\ndeclined significantly (females: E?LV: 14.7 +/- 2.6 to 13.6 +/- 2.9 cm/s; males: 15.2 +/- 2.2 to 13.9 +/- 2.3 cm/s, p < 0.001\nfor both). Similarly, 2D strain decreased significantly following exercise (2D strain LV: from 21.5 +/- 2.4 to 20.2 +/- 2.7%\nin females, and from 20 +/- 1 to 17.9 +/- 1.5% in males, p < 0.05 for both). However, there were no significant changes\nin LV contractility estimated by elastance in either sex following exercise (p > 0.05). Arterial elastance) Ea) at baseline\nwas identified as the only predictor of VO2max in males (r = 0.76, p < 0.001) but not in females (p > 0.05).\nConclusions: The present study demonstrates that vigorous exercise of short duration results in a significant decrease\nof longitudinal myocardial motion in both sexes. However, in view of unaltered end systolic LV elastance (Ees), these\nreductions most probably reflect changes in the loading conditions and not an attenuation of myocardial function\nper se. Importantly, we show that arterial load at rest acts as a strong predictor of VO2max in males but not in female\nsubjects....
The increased participation of children and adolescents in organized sports worldwide is a welcome trend given\nevidence of lower physical fitness and increased prevalence of overweight in this population. However, the\nincreased sports activity of children from an early age and continued through the years of growth, against a\nbackground of their unique vulnerability to injury, gives rise to concern about the risk and severity of injury. Three\ntypes of injuryââ?¬â??anterior cruciate ligament (ACL) injury, concussion, and physeal injury ââ?¬â?? are considered potentially\nserious given their frequency, potential for adverse long-term health outcomes, and escalating healthcare costs.\nConcussion is probably the hottest topic in sports injury currently with voracious media coverage and exploding\nresearch interest. Given the negative cognitive effects of concussion, it has the potential to have a great impact on\nchildren and adolescents during their formative years and potentially impair school achievement and, if concussion\nmanagement is not managed appropriately, there can be long term negative impact on cognitive development\nand ability to resume sports participation. Sudden and gradual onset physeal injury is a unique injury to the\npediatric population which can adversely affect growth if not managed correctly. Although data are lacking, the\nfrequency of stress-related physeal injury appears to be increasing. If mismanaged, physeal injuries can also lead to\nlong-term complications which could negatively affect ability to participate in sports. Management of ACL injuries is\nan area of controversy and if not managed appropriately, can affect long-term growth and recovery as well as the\nability to participate in sports. This article considers the young athleteââ?¬â?¢s vulnerability to injury, with special reference\nto ACL injury, concussion, and physeal injury, and reviews current research on epidemiology, diagnosis, treatment,\nand prevention of these injury types. This article is intended as an overview of these injury types for medical\nstudents, healthcare professionals and researchers....
Background: Physical inactivity is a major cardiovascular risk factor. Recently, we showed that non-exercise activity\nthermogenesis (NEAT) assessed by the self-reported questionnaire is favorably associated with metabolic risks in\npatients with type 2 diabetes. The purpose of the present study was to examine the validity of the questionnaire\nby comparing with objectively measured daily physical activity (PA) by using the triaxial accelerometer.\nMethods: Daily physical activity level (PAL) of 51 participants (24 men and 27 women) with type 2 diabetes was\nmeasured by the triaxial accelerometer. At the same time, we evaluated their NEAT score using our original\nquestionnaire modified from a compendium of physical activities.\nResults: The NEAT score was significantly and positively correlated with PAL measured by the triaxial accelerometer\n(r = 0.604, P < 0.001). PAL was also significantly and positively correlated with both the locomotive NEAT score\nand the non-locomotive NEAT score (r = 0.444, P = 0.001 and r = 0.526, P < 0.001, respectively).\nConclusions: The NEAT score measured by the self-reported questionnaire was highly correlated with PAL\nmeasured by the triaxial accelerometer. Our original NEAT questionnaire may be useful for evaluation of daily PAL\nin clinical practices....
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