International SportMed Journal - Volume 14, Issue 1, 2013
Volume 14, Issue 1, 2013
Electromyographic analysis of posterior deltoid, posterior rotator cuff and trapezius musculature in different shoulder exercises : original research articleSource: International SportMed Journal 14, pp 1 –15 (2013)More Less
Background : The shoulder external rotator muscles and the different portions of the trapezius muscle have never been studied in exclusivity. However, the literature has provided several exercises which have been used in this study.
Purpose : To quantify electromyographic activity of the shoulder external rotator muscles and the upper, middle and lower trapezius in seven exercises.
Methods : 20 healthy males performed 7 exercises in random order. Surface electromyography was recorded for the posterior deltoid, infraspinatus, teres minor, upper, middle and lower trapezius.
Results : The four prone exercises presented the highest levels of EMG activation in the External Rotators Synergy (the average activation of arm external rotator muscles group) and in the Trapezius Synergy (the average activation of the three portions of trapezius). The infraspinatus muscle obtained the highest activation values in exercises 1 (prone horizontal abduction at 90° with full external rotation, thumb up ), 4 (prone external rotation at 90° abduction and elbow at 90°), and 5 (side-lying ER with elbow on the trunk). The highest activation level of the teres minor muscle was found in Exercise 1.
Conclusions : The four prone exercises demonstrated the highest EMG activity in the shoulder, considering both the external rotator muscles and the trapezius. However, if the focus of the strength training process is mainly to strengthen the two external rotator muscles of the rotator cuff, with an adequate intramuscular coordination pattern for the trapezius, the side lying ER with the elbow resting on the trunk seems to be the most appropriate exercise.
Source: International SportMed Journal 14, pp 16 –28 (2013)More Less
Introduction : Reduced VO2 peak, muscle mass, increased fat mass and immunosenescence have been associated with aging. This study examined the effects of exercise on selected cytokines in younger and older individuals, and after 12 weeks of aerobic exercise training in older individuals.
Methods : Serum levels of interleukin-6 (IL-6), interleukin-1 beta (IL-1 β) and interleukin-10 (IL-10) were measured before and after maximal and sustained submaximal (70% VO2 peak) tests in sedentary young (22 ± 3 years, BMI = 24.9 ± 3.7 kg/m2) and older subjects (75 ± 7 years, BMI = 25.1 ± 3.5 kg/m2) prior to and after training.
Results : There were no significant differences in baseline levels of IL-1 β, IL-6 or IL-10 between younger and older subjects. In younger subjects, IL-6 (33%) and IL-1 β (25%) were increased after the maximal exercise test, whereas IL-6 was increased (112%) after the submaximal test (P < 0.05). In older subjects pre-training, levels of IL-6, IL-1 β and IL-10 were not affected by acute exercise. In older subjects after training, IL-6 increased in response to acute maximal and submaximal exercise, 17% and 44%, respectively.
Conclusion : Older subjects did not demonstrate a significant inflammatory response (IL-1 β) to acute exercise; however their anti-inflammatory (IL-6) response was blunted, and was only partially restored by 12 weeks of exercise training. Further studies are needed to examine the effects of longer-term chronic exercise on immune parameters.
Source: International SportMed Journal 14, pp 29 –35 (2013)More Less
Background : Vascular endothelial growth factor (VEGF), which acts via receptor VEGFR2, is a major growth polypeptide for regulating skeletal muscle angiogenesis.
Type of study : Original research concerned the genetic background of physical performance.
Research question : The aim of the study was to analyse the possible importance of the His472Gln polymorphism within the VEGFR2 gene in endurance athletes and sedentary individuals, in order to reveal the possible relationships between genotype and physical performance.
Methods : In this study, the His472Gln polymorphism (rs1870377), derived from the VEGFR2 gene, was studied in 176 male Polish endurance athletes of a nationally competitive standard and 161 unrelated volunteers for controls. Genotyping was carried out by PCR-RFLP. Significance was assessed by Chi square (X2) analysis.
Results : The results revealed that the frequency of the VEGFR2 Gln/Gln genotype (21.02% vs.10.56%; P = 0.014) and 472Gln allele (41.19% vs. 29.50%; P = 0.001) was significantly higher in the endurance-orientated athletes compared to sedentary controls.
Conclusion : In conclusion, our results suggest that the VEGFR2 gene may be taken into consideration as a genetic marker in endurance-oriented athletes. However, this conclusion should be interpreted with great caution and be supported with more experimental studies on the VEGFR2 polymorphisms in elite athletes.
Source: International SportMed Journal 14, pp 36 –43 (2013)More Less
Background : TAG rugby is a popular sport in Ireland, with an estimated 8,000 regular participants.
Research question : To evaluate the incidence of self-reported injury in TAG rugby players at a single venue over the final four weeks of a ten-week competition.
Type of study : Two questionnaire-based components.
Methods : The first component involved a cohort of eighty players followed over a four-week period. Any injuries sustained were recorded by self-report on the day. The second, a cross-sectional analysis of injuries in a separate group of one hundred and fifty players, was recorded by self-report at the end of the same period.
Results : Sixteen injuries occurred in the eighty-player cohort during the study period. The majority were to the lower and upper limb. In a mixed social group of players, there was no difference (p=0.19) in the occurrence of injuries between males and females, however injuries were more frequent in those that did not warm up (p=0.014). The outcomes from the second questionnaire component supported the cohort data, with the risk of injury being unrelated to sex, age, previous playing experience, level of expertise or the wearing of studs.
Conclusion : This is the first study to determine a self-reported injury rate for TAG rugby. An injury rate of one injury per 8.9 hours of competitive play was observed, with similar rates in males and females. Any period of warm-up prior to play was associated with fewer injuries. This suggests that warm-up is an important injury prevention strategy during TAG rugby competition.