Electromyographic analysis of lower limb muscles during the golf swing performed with three different clubs

The aim of this study was to describe and compare the EMG patterns of select lower limb muscles throughout the golf swing, performed with three different clubs, in non-elite middle-aged players. Fourteen golfers performed eight swings each using, in random order, a pitching wedge, 7-iron and 4-iron. Surface electromyography (EMG) was recorded bilaterally from lower limb muscles: tibialis anterior, peroneus longus, gastrocnemius medialis, gastrocnemius lateralis, biceps femoris, semitendinosus, gluteus maximus, vastus medialis, rectus femoris and vastus lateralis. Three-dimensional high-speed video analysis was used to determine the golf swing phases. Results showed that, in average handicap golfers, the highest muscle activation levels occurred during the Forward Swing Phase, with the right semitendinosus and the right biceps femoris muscles producing the highest mean activation levels relative to maximal electromyography (70–76% and 68–73% EMG_MAX, respectively). Significant differences between the pitching wedge and the 4-iron club were found in the activation level of the left semitendinosus, right tibialis anterior, right peroneus longus, right vastus medialis, right rectus femuris and right gastrocnemius muscles. The lower limb muscles showed, in most cases and phases, higher mean values of activation on electromyography when golfers performed shots with a 4-iron club.     

Perceived environment in relation to objective and self-reported physical activity in Spanish youth. The UP&DOWN study

The aims of the present study were to assess the association of environmental perception with objective and self-reported physical activity (PA) and the relation between environmental perception and meeting PA recommendations on children and adolescents. A sample of 1520 youth (770 boys) aged 8–18 years (12.1 ± 2.5 years) from the UP&;DOWN study were included in the data analyses. Environmental perception was assessed with the short adapted version of the ALPHA environmental questionnaire. PA was objectively (accelerometers) and self-reported measured (PA Questionnaire for Children, Patient-centered Assessment and Counseling for Exercise Questionnaire and Finnish PA Index). Linear regression models were used to assess the association of environmental perception with PA. Bivariate logistic regression models were used to assess differences between environmental perception and meeting PA recommendations. Environmental perception was positively associated with both objective and self-reported PA. Some differences were found in the association of environmental perception and PA between sex- and age-specific groups. Youth who perceived a more favourable environment were more likely to meet PA recommendations (at least 60 min · day^?1 of moderate to vigorous PA (MVPA)). Results suggest that environmental perceptions of children and adolescents may play an important role in achieving higher levels of PA.     

Space occupation near the basket shapes collective behaviours in youth basketball

This study aimed to analyse how youth basketball players explored numerical overloads during shot attempts by measuring their space occupation across specific court areas. Four process-tracing variables measured how the number of attackers (NA), number of defenders (ND), interpersonal distance between attacker and the closest defender (ID) and distance between attacker and the basket (DBkt) impacted on the performance outcome (converted shot; missed shot; ball possession lost). Ten competitive games involving 13 U14 teams were video recorded and players’ displacements were digitised. The associations between performance outcomes and the process-tracing measures were assessed using standardised mean differences and a cross-correlation function. A multinomial logistic regression was used to calculate the odds ratio (OR) for each of the three possible outcomes. Results revealed that when shot attempts occurred at larger ID and at smaller DBkt, the possibilities to obtain a converted shot increased. The numerical overload of defenders near the scoring target was predominantly associated with offensive success. Also, the possibility of attackers to lead the spatial relation of movements with the defenders, near the scoring target, appeared as a prominent strategy to succeed. In sum, basketball teams that exhibit potential to adapt their collective behaviours to local changes in the environment might be closer to achieving successful outcomes.     

Revealing the decision-making of dribbling in the sport of futsal

ABSTRACT

This study aimed to investigate why futsal players decide to dribble. For this purpose, we analysed 396 trials comprising the dribbles (n = 132), passes (n = 131) or shots (n = 133), performed by 70 male futsal players. Passing and shooting angles, and interpersonal distance, including their rates of change (velocity and variability), were regarded as measures of interpersonal coordination tendency and a comparison was made among dribbling, passing and shooting situations. In addition, the variables identified as constraints on deciding to dribble were analysed in relation to age categories, dribbling outcomes and futsal court zone. Results revealed that passing and shooting angles, and interpersonal distance showed higher variability in dribbling than in passing and shooting situations. The findings allowed us to conclude that decision-making on dribbling was influenced by the variabilities of passing angles as well as shooting and interpersonal distance, and that success in dribbling was affected by the variability of interpersonal distance. Such variabilities were interpreted concerning their meaning of risk and/or uncertainty in the execution of motor skills.     

Medieval Córdoba: From Umayyad Recreations to Competitive Christian Sport

Abstract

In this article, we study the evolution of competitive sport and sporting recreations in medieval Córdoba, from the Umayyad Muslims (756–1236) to the Christians (since 1236). In this diachronic study, firstly we compare the competitive sport and sporting recreations of the Muslim East (especially those of the Abbasid period) with those of Muslim Córdoba, in order to know the level of Arabization of those practices in Córdoba, and if competitive sport is more predominant than recreations or vice versa. Secondly, we study if competitive sport and sporting recreations had the same presence in Muslim Córdoba and Christian Córdoba (or if one predominated over the other), and the possible reasons for it. We conclude: (1) that in Muslim Córdoba, sporting recreations were more important than competitive sport, unlike what happened in the great Muslim cities of the East; (2) Arabization is almost total regarding the types of sport and recreations implanted in Córdoba but low regarding horse sports and the importance of competitive sport; and (3) that Christian Córdoba shows a very different character, since competitive sport is very important (largely because by that time Córdoba had become a frontier city).     

Sport Versus Bullfighting: The New Civilizing Sensitivity of Regenerationism and its Effect on the Leisure Pursuits of the Spanish at the Beginning of the Twentieth Century

Abstract

This article analyzes the influence of the new civilizing sensitivity of the Spanish regenerationists in the introduction of sport, in place of bullfighting, during the first third of the twentieth century. Following the colonial collapse of the late nineteenth century and the subsequent demoralization of the country, the regenerationists saw in physical education and sport a way to reform the broken Spanish population. Sport had arrived in Spain in the mid-nineteenth century by way of the aristocracy and would then spread to the urban middle classes, imbued with the reformist sense of the regenerationists. It came in the form of amateur sport, with values of modernity and a civilizing sensitivity which were diametrically opposed to activities such as bullfighting that had such great support from the Spanish public. Amongst the urban middle classes, sport developed as a kind of amateur practice, used for the formation of a more civilized character and the expression of individuality; on the contrary, amongst the working classes, sport spread primarily in its professional form, by way of mass spectator sports (football and boxing), representing a civilizing spurt in severing the link between entertainment and death which was central to bullfighting.     

A survey of sensor devices: use in sports biomechanics

This paper examines the use of sensor devices in sports biomechanics, focusing on current frequency of use of Electromyography (EMG) device preferences. Researchers in the International Society of Biomechanics in Sports were invited to participate in an online survey. Responses on multiple sensor devices highlighting frequency of use, device features and improvements researchers sought in acquisition and analysis methods were obtained via an online questionnaire. Results of the investigation showed that the force platform is the most frequently used device, with inertial measurement units and EMG devices growing in popularity. Wireless functionality and ease of use for both the participant and the practitioner proved to be important features. The main findings of the survey demonstrated need for a simple, low power, multi-channel device which incorporates the various sensors into one single device. Biomechanists showed they were looking for more availability of wireless sensor devices with acquisition and analysis features. The study found there is a need to develop software analysis tools to accompany the multi-channel device, providing all the basic functions while maintaining compatibility with existing systems.     

Non-linear resistance training reduces inflammatory biomarkers in persons living with HIV: A randomized controlled trial

The purpose of this study is to analyse the effect of 12 weeks of non-linear resistance training (NLRT) on anthropometry, muscle strength and inflammatory biomarkers in persons infected with human immunodeficiency virus (PIHIV). Thirty previously sedentary PIHIVs were randomized into the NLRT (n?=?15) and control (CON, n?=?15) groups. NLRT group were submitted to 12 weeks of training, whereas the CON group maintained their daily habits. At baseline and after 12 weeks, both groups underwent anthropometric evaluations and blood sampling for the analysis of inflammatory biomarkers. Analysis of covariance using preintervention values as covariate was performed to determine the effects of exercise on anthropometry, muscle strength, cytokines levels and T cells. Significance was set at p?p?p p?=?.009), blood levels of interleukin (IL)-1β (p?=?.029), IL-6 (p?=?.005), IL-8 (p?=?.010), and tumour necrosis factor (TNF)-α (p?=?.001) and an increase in muscle strength (p?p?=?.030) and CD4⁺ (p?=?.004) and CD8⁺ (p?相似文献   

Male professional tennis players maintain constant serve speed and accuracy over long matches on grass courts

The potential effect of fatigue on stroke production in tennis players is still controversial. The aim of this study was to analyse the tennis serve speed and accuracy in prolonged male professional matches played on grass courts. We analysed tennis serve statistics from five-set Wimbledon matches (n?=?15; 30 players). Results showed that match duration averaged 208.3?±?28.3?min. The overall serve speed was 177.0?±?10.2?km/h in the first set and 176.1?±?11.7?km/h in the fifth set (p?=?.34). The difference of all accuracy values of first set serves was not significantly different from those of the fifth set: percentage of valid first serves, 63.1?±?11.1% vs. 62.3?±?11.8%, respectively (p?=?.78); percentage of “aces”, 11.2?±?9.1% vs. 10.0?±?8.9%, respectively (p?=?.39); percentage of “winners”, 2.6?±?7.6% vs. 1.2?±?2.2%, respectively (p?=?.36); percentage of “double faults”, 2.8?±?3.0% vs. 2.8?±?3.4% (p?=?.97). In conclusion, tennis players were able to maintain constant serve speed and accuracy over five-set matches played on grass courts. Professional tennis players are capable of overcoming fatigue and/or make movement adjustments to effectively perform complex technical strokes like the serve throughout matches played on grass courts lasting more than 3?h in average.     

Higher bone mass in prepubertal and peripubertal female footballers

Objectives: The main aim of this study was to compare the bone mass of female football players with controls of different pubertal stages. Methods: Sixty five girls aged 8–14 years (10.14?±?0.1, Tanner stages I–IV) participated in the study. Twenty participants were prepubertal (10 prepubertal control) and 45 peripubertal (15 peripubertal control). All footballers trained two days per week while the control group did not perform regular physical activity outside of school. Body composition was assessed by Dual-energy X-ray absorptiometry. Analysis of covariance was performed to evaluate differences in lean and bone masses. Results: Significant differences in lower-body extremities lean mass (LLM) between peripubertal groups were found (P?P?P?Conclusion: Female footballers showed higher bone and lean masses compared to control counterparts; these differences are already detectable at prepubertal ages and more consistent after pubertal spurt.