Current Issue : July - September Volume : 2015 Issue Number : 3 Articles : 6 Articles
Research into the detrimental effects of excessive exercise has been conceptualized in a number of similar ways,\nincluding ââ?¬Ë?exercise addictionââ?¬â?¢, ââ?¬Ë?exercise dependenceââ?¬â?¢, ââ?¬Ë?obligatory exercisingââ?¬â?¢, ââ?¬Ë?exercise abuseââ?¬â?¢, and ââ?¬Ë?compulsive\nexerciseââ?¬â?¢. Among the most currently used (and psychometrically valid and reliable) instruments is the Exercise\nAddiction Inventory (EAI). The present study aimed to further explore the psychometric properties of the EAI by\ncombining the datasets of a number of surveys carried out in five different countries (Denmark, Hungary, Spain, UK,\nand US) that have used the EAI with a total sample size of 6,031 participants. A series of multigroup confirmatory\nfactor analyses (CFAs) were carried out examining configural invariance, metric invariance, and scalar invariance. The\nCFAs using the combined dataset supported the configural invariance and metric invariance but not scalar\ninvariance. Therefore, EAI factor scores from five countries are not comparable because the use or interpretation of\nthe scale was different in the five nations. However, the covariates of exercise addiction can be studied from a\ncross-cultural perspective because of the metric invariance of the scale. Gender differences among exercisers in the\ninterpretation of the scale also emerged. The implications of the results are discussed, and it is concluded that the\nstudyââ?¬â?¢s findings will facilitate a more robust and reliable use of the EAI in future research....
Background: The ACTN3 gene may influence performance in team sports, in which sprint action and high-speed\nmovements, regulated by the anaerobic energy system, are crucial to the ultimate success of a match. The aim of\nthis study was to determine the association between the ACTN3 R577X (rs1815739) polymorphism and elite team\nsport athletic status in Italian male athletes.\nMethods: We compared the genotype and allele frequency of the ACTN3 R577X polymorphism between team\nsport athletes (n = 75), endurance athletes (n = 40), sprint/power athletes (n = 64), and non-athletic healthy controls\n(n = 192) from Italy. Genomic DNA was collected using a buccal swab. Extraction was performed according to the\nmanufacturer�s directions provided with a commercially available kit (Qiagen S.r.l., Milan, Italy).\nResults: Team sport athletes showed a lower frequency of the 577RR genotype compared to the 577XX genotype\nthan sprint/power athletes (p = 0.044). However, the ACTN3 R577X polymorphism was not associated with team\nsport athletic status compared to endurance athletes and non-athletic controls.\nConclusions: Our results agree with a recent large-scale study involving athletes from Spain, Poland, and Russia.\nThe ACTN3 R577X polymorphism was not associated with team sport athletic status compared to endurance\nathletes and non-athletic controls....
Background: The present article systematically reviews recent literature on the in vivo adaptation of asymptomatic\nhuman tendons following increased chronic mechanical loading, and meta-analyzes the loading conditions,\nintervention outcomes, as well as methodological aspects.\nMethods: The search was performed in the databases PubMed, Web of Knowledge, and Scopus as well as in the\nreference lists of the eligible articles. A study was included if it conducted (a) a longitudinal exercise intervention\n(?8 weeks) on (b) healthy humans (18 to 50 years), (c) investigating the effects on mechanical (i.e., stiffness),\nmaterial (i.e., Youngâ��s modulus) and/or morphological properties (i.e., cross-sectional area (CSA)) of tendons in vivo,\nand was reported (d) in English language. Weighted average effect sizes (SMD, random-effects) and heterogeneity\n(Q and I2 statistics) of the intervention-induced changes of tendon stiffness, Youngâ��s modulus, and CSA were\ncalculated. A subgroup analysis was conducted regarding the applied loading intensity, muscle contraction type,\nand intervention duration. Further, the methodological study quality and the risk of bias were assessed.\nResults: The review process yielded 27 studies with 37 separate interventions on either the Achilles or patellar\ntendon (264 participants). SMD was 0.70 (confidence interval: 0.51, 0.88) for tendon stiffness (N=37), 0.69 (0.36, 1.03)\nfor Youngâ��s modulus (N=17), and 0.24 (0.07, 0.42) for CSA (N=33), with significant overall intervention effects\n(p<0.05). The heterogeneity analysis (stiffness: I2=30%; Youngâ��s modulus: I2=57%; CSA: I2=21%) indicated that\ndifferences in the loading conditions may affect the adaptive responses. The subgroup analysis confirmed that\nstiffness adaptation significantly (p<0.05) depends on loading intensity (I2=0%), but not on muscle contraction type.\nAlthough not significantly different, SMD was higher for interventions with longer duration (?12 weeks). The\naverage score of 71�±9% in methodological quality assessment indicated an appropriate quality of most studies.\nConclusions: The present meta-analysis provides elaborate statistical evidence that tendons are highly responsive\nto diverse loading regimens. However, the data strongly suggests that loading magnitude in particular plays a key\nrole for tendon adaptation in contrast to muscle contraction type. Furthermore, intervention-induced changes in\ntendon stiffness seem to be more attributed to adaptations of the material rather than morphological properties....
Running economy (RE) is considered an important physiological measure for endurance athletes, especially distance\nrunners. This review considers 1) how RE is defined and measured and 2) physiological and biomechanical factors that\ndetermine or influence RE. It is difficult to accurately ascertain what is good, average, and poor RE between athletes\nand studies due to variation in protocols, gas-analysis systems, and data averaging techniques. However, representative\nRE values for different caliber of male and female runners can be identified from existing literature with mostly clear\ndelineations in oxygen uptake across a range of speeds in moderately and highly trained and elite runners. Despite\nbeing simple to measure and acceptably reliable, it is evident that RE is a complex, multifactorial concept that reflects\nthe integrated composite of a variety of metabolic, cardiorespiratory, biomechanical and neuromuscular characteristics\nthat are unique to the individual. Metabolic efficiency refers to the utilization of available energy to facilitate optimal\nperformance, whereas cardiopulmonary efficiency refers to a reduced work output for the processes related to oxygen\ntransport and utilization. Biomechanical and neuromuscular characteristics refer to the interaction between the neural\nand musculoskeletal systems and their ability to convert power output into translocation and therefore performance.\nOf the numerous metabolic, cardiopulmonary, biomechanical and neuromuscular characteristics contributing to RE,\nmany of these are able to adapt through training or other interventions resulting in improved RE....
Proprioception is the sense of awareness of position of one’s limb and orientation of body part with respect to the other and the environment. Hence, proprioception helps in planning and maintaining optimal amount of motion which inturn helps in preventing injury. It may vary due to many factors like degenerative changes, activity level, injury, age, gender and dominance. Hence the present study was conducted with an objective to study the differences in proprioception of knee joint with age, gender and dominance in healthy asymptomatic individuals.90 healthy asymptomatic individuals were allocated to 3 groups by age as 21-40yrs, 41-60yrs and 61-80years. Proprioception was assessed for bilateral knee joint using digital goniometer. The individuals were also assessed for lower limb dominance. Average of 3 readings was considered for analysis.There was steady decline observed in proprioception with increasing age. There was no significant difference in gender at younger age but proprioception declined in females more than their male counterparts at older age group and there was no difference observed with dominance of lower limbs....
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