Topic Review
Bodybuilding and Myostatin
MSTN is a gene that makes instructions for producing the protein myostatin, a protein that is part of the transforming growth factor beta family (TGFβ). The TGFβ family of proteins control the growth of tissues in the body, myostatin is found nearly exclusively in the skeletal muscles where it is active before and after birth. The protein actually controls skeletal growth by restraining it, preventing muscles becoming excessively large. Current research that surrounds myostatin is based around its potential treatment in muscle wasting disorders, animals that have mutations in the encoding gene MSTN show greater muscle mass, strength and in some circumstances reduced bodyfat, which can be known as myostatin-related muscle hypertrophy. This study aimed to see the prevalence of mutations in the male bodybuilder population (n = 92) and if having a mutation had any affect on their muscle size and/or muscle performance. The study which looked at mutation prevalence in rs1805086, arm circumference, pull-up max and push-up max. The results show that 17% (16) of the subject group had one mutation (AG), 83% (76) had the common outcome (AA) and 0% (0) had two mutations (GG). Those with the AG outcome had an average arm circumference of 46.37cmcompared with AA which had an average of 42.02cm. Those with the AG outcome had an average pull-up max score of 21 compared with AA with an average of 12. Those with the AG outcome had an average push-up max of 61 compared with AA with an average of 40. The study clearly shows that those with a mutation are rare, however the mutation does appear to give the subject a performance and size advantage over those with the common outcome.
  • 3898
  • 03 Nov 2020
Topic Review
Biomechanics of Table Tennis
Table tennis is a popular recreational and competitive sports at all levels. Recent research on table tennis maneuvers identified the differences between playing levels and between maneuvers using parameters which included ball and racket speed, joint kinematics and kinetics, electromyography, and plantar pressure distribution. Different maneuvers underlined changes on body posture and lines of movement which were accommodated particularly by the racket face angle, trunk rotation, knee and elbow joint movements, and thus different contributions of muscles. Higher-level players produced ball and strike at higher accuracy and repeatability but not necessarily lead to higher speed. In addition, higher-level players utilize superior whole-body coordination and footwork to compromise between agility and stability for a quality strike. Strengthening shoulder and wrist muscles could enhance the speed of the strike while personalized training shall be considered since motor coordination and adaptation vary among individuals.
  • 3286
  • 29 Oct 2020
Topic Review
Nonparametric Limits of Agreement
The assessment of agreement in method comparison and observer variability analysis of quantitative measurements is usually done by the Bland-Altman Limits of Agreement, where the paired differences are implicitly assumed to follow a normal distribution. Whenever this assumption does not hold, the 2.5% and 97.5% percentiles are obtained by quantile estimation. In the literature, empirical quantiles have been used for this purpose. In this simulation study, we applied both sample, subsampling, and kernel quantile estimators as well as other methods for quantile estimation to sample sizes between 30 and 150 and different distributions of the paired differences. The performance of 15 estimators in generating prediction intervals was measured by their respective coverage probability for one newly generated observation. Our results indicated that sample quantile estimators based on one or two order statistics outperformed all the other estimators and can be used for deriving nonparametric Limits of Agreement. For sample sizes exceeding 80 observations, more advanced quantile estimators, such as the Harrell-Davis and estimators of Sfakianakis-Verginis type, which use all the observed differences, performed likewise well, but may be considered intuitively more appealing than simple sample quantile estimators that are based on only two observations per quantile.
  • 1427
  • 27 Oct 2020
Topic Review
Football Goalkeeper Injuries
Knowledge and research about football goalkeeper (GK) injuries are scarce, which prevents the development of evidence-based injury prevention programs. Fortunately, progress is evident in injury prevention strategies in outfield football players. However, a GK fulfills a unique role, and an injured GK can substantially impact a team. Thus, there is a need to clarify and summarize current knowledge concerning football goalkeeper pain and injuries.
  • 1009
  • 31 May 2021
Topic Review
Physical Activity Patterns
Although “physical activity pattern” (PAP) is a widely used expression, its precise meaning remains vague. Indeed, PAP is sometimes used to describe physical activity (PA) levels/intensities, however the term is also applied to express how PA averages differ among group,  between different days (i.e., week and weekend days), across seasons (e.g., summer, winter), and between school and vacation time. A lack of a formal definition for PAP has not prevented researchers from using a vast array of instruments to measure PA (accelerometers, pedometers, questionnaires, direct observations, and heart rate monitors) in an attempt to capture PAP. Discrepancies also exist in how PAP has been expressed with researchers using daily mean PA, heart rate frequency, number of daily steps, time engaged in certain types of activity, and/or engagement in sports activities. Researchers have also used numerous statistical procedures in their attempts to capture PAP. Notwithstanding this diversity, we suggest that PAP should be used to jointly capture similarities/dissimilarities as well as stabilities/changes in children’s PA at an intra-personal level. PAP should be used to best describe individual streams of behaviours, and not exclusively PA levels/intensities. A formal and clear definition of PAP would support important, systematic, and coherent lines of empirical enquiry.
  • 842
  • 24 Apr 2021
Topic Review
Physiotherapy treatment for Dysphagia
Dysphagia (DP) is a condition characterised by the loss of swallowing function, due to the alteration of the oral route and of the pharyngeal and esopharyngeal phases, hindering or impeding the passage of the alimentary bolus from the mouth to the stomach. DP affects 13% of people over 65 years of age and approximately 33% of people over 80 years of age, although it has a prevalence of 55% after a stroke. The most common complications associated with this disorder are: suffocation, aspiration pneumonia, malnutrition and decreased physical activity; these must be addressed with special care and individually.
  • 787
  • 27 Oct 2020
Topic Review
Electromyography in Sports
Muscular alterations as a consequence of hypoxic situations contribute not only to a decrease in life expectancy but also to a lower quality of life and health status. Our perspective, based on the results of this systematic review, is that Electromyography (EMG) is a suitable tool for monitoring the different skeletal muscle responses and has sufficient sensitivity to detect the muscle changes produced by hypoxic stimuli. Therefore, surface EMG (sEMG) maybe provide a practical point-of-care diagnostic test for medical diagnoses as well as a tool to improve sports performance. integrated EMG (iEMG) studies the physiology and pathology of denervation, re-innervation, and various myopathies. It also analyzes deep musculature such as muscular behavior, temporal activity patterns, fatigue, and muscular activation. sEMG is suitable for providing information about global muscle behavior, temporal activity patterns, muscle fatigue, and the activation level of the superficial musculature.
  • 510
  • 15 Jan 2021
Topic Review
Judo-Specific Training
Reaching peak judo performance requires the optimal development of technical-tactical, physical, physiological and psychological abilities. High-intensity interval training (HIIT), including general and specific movements, is a training method often used in judo to simultaneously improve multiple aspects of performance. Combat simulation (randori) or throwing technique exercises (uchi-komi, technique repetition without throwing the partner and nage-komi, throwing technique repetition throwing the partner) as specific training methods are regularly used in judo. HIIT using uchi-komi as exercise and performed in all-out mode improves anaerobic and aerobic fitness while allowing technical skill development for judo athletes.
  • 457
  • 05 Nov 2020
Topic Review
Research in instability has focused on the analysis of muscle activation. This systematic entry was to analyze the effects of unstable devices on speed, strength and muscle power measurements administered in the form of controlled trials to healthy individuals in adulthood. 
  • 413
  • 27 Jan 2022
Topic Review
Physical Fitness in Adulthood
The aim of the entry is the elaboration of a systematic review of existing research on physical fitness, self-efficacy for physical exercise, and quality of life in adulthood. Method: Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement guidelines, and based on the findings in 493 articles, the final sample was composed of 37 articles, which were reviewed to show whether self-efficacy has previously been studied as a mediator in the relationship between physical fitness and quality of life in adulthood. Results: The results indicate that little research exists in relation to healthy, populations with the majority being people with pathology. Physical fitness should be considered as a fundamental aspect in determining the functional capacity of the person. Aerobic capacity was the most evaluated and the 6-min walk test was the most used. Only one article shows the joint relationship between the three variables. Conclusions: We discuss the need to investigate the mediation of self-efficacy in relation to the value of physical activity on quality of life and well-being in the healthy adult population in adult life.
  • 407
  • 11 Sep 2020
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