1,721,094 research outputs found
Muscle damage and repeated bout effect induced by enhanced eccentric squats
Full text linkBACKGROUND: Muscle damage and repeated bout effect have been studied after pure eccentric-only exercise. The aim of this study was to evaluate muscle damage and repeated bout effect induced by enhanced eccentric squat exercise using flywheel device. METHODS: Thirteen healthy males volunteered for this study. Creatine kinase blood activity (CK), quadriceps isometric peak torque and muscle soreness were used as markers of muscle damage. The dependent parameters were measured at baseline, immediately after and each day up to 96 hours after the exercise session. The intervention consisted of 100 repetitions of enhanced eccentric squat exercise using flywheel device. The same protocol was repeated after 4 weeks. RESULTS: After the first bout, CK and muscle soreness were significantly greater (P<0.05) than baseline respectively up to 72 and 96 hours. Isometric peak torque was significantly lower (P<0.05) up to 72 hours. After the second bout, CK showed no significant increase (P>0.05), while isometric peak torque and muscle soreness returned to values similar to baseline after respectively 48 and 72 hours. All muscle damage markers were significantly lower after second compared to first bout. CONCLUSIONS: The enhanced eccentric exercise induced symptoms of muscle damage up to 96 hours. However, it provided muscle protection after the second bout, performed four weeks later. Although it was not eccentric-only exercise, the enhancement of eccentric phase provided muscle protection
Effects of recreational football performed once a week (1 hour per 12 weeks) on cardiovascular risk factors in middle-aged sedentary men
Full text linkObjectives: It is well established that there is a strong relationship between physical activity, cardiovascular diseases and mortality. Regular recreational football training can lower blood pressure, heart rate at rest, fat percentage, LDL cholesterol and increase maximal aerobic power (VO2max). This study analyzed the effect of one recreational football training per week on middle-aged men. Design: Randomized controlled trial. Methods: Twenty-four participants (mean ± SDs; age 44.5 ± 4.7 years, weight 81.9 ± 10.4 kg, height 175.0 ± 7.3 cm) were randomized in a football group (FG = 10) and control group (CG = 14). FG performed supervised recreational football training (five-a-side futsal match) on 36 × 18.5 m synthetic indoor and outdoor field, 60 min per week over 12 weeks. Results: After training, VO2max and maximal aerobic speed improved in FG respectively of 4.4% (+1.89 mL O2⋅ kg−1.min−1 , P = 0.002) and 5.9% (P = 0.01). Systolic and mean blood pressure decreased respectively of 2.5% (−3.18 mmHg, P = 0.04) and 2.2% (−2.28 mmHg, P = 0.04) in FG, while diastolic blood pressure did not change (−1.84 mmHg, P = 0.09). Conclusions: Recreational football activity produces health benefits by improving VO2 max and lowering blood pressure parameters in middle-aged men
Eccentric resistance training increases and retains maximal strength, muscle endurance and hypertrophy in trained men
No full textThe aim of the present study was to evaluate the effects of different resistance training protocols on muscle strength, endurance, and hypertrophy after training and detraining. Thirty-four resistance-trained males were randomized in concentric-only (CONC), eccentric-only (ECC), traditional concentric-eccentric (TRAD) bench press resistance training or control group. The training volume was equalized among the intervention groups. Bench press of 1-repetition maximum (1RM)/body mass, maximum number of repetitions (MNR), and chest circumference were evaluated at the baseline, after 6 weeks of training, and after 6 weeks of detraining. All intervention groups reported significant 1RM/body mass increases after training (CONC baseline: 1.04 ± 0.06, post-training: 1.12 ± 0.08, p < 0.05; ECC baseline: 1.08 ± 0.04, post-training: 1.15 ± 0.05, p < 0.05; TRAD baseline: 1.06 ± 0.08, post-training: 1.11 ± 0.10, p < 0.05). After detraining, only ECC retained 1RM/body mass above the baseline (1.17 ± 0.07, p < 0.05), while CONC and TRAD returned to baseline values. Only ECC improved and retained MNR (baseline: 22 ± 3; post-training: 25 ± 3, and post-detraining: 25 ± 4, p < 0.05 compared with baseline) and chest circumference (baseline: 98.3 ± 2.4 cm, post-training: 101.7 ± 2.2 cm and post-detraining: 100.7 ± 2.3 cm. p < 0.05 compared with baseline), while no significant changes occurred in both CONC and TRAD. The incorporation of eccentric training can be recommended for counteracting the negative effects of detraining or forced physical inactivity
Isoload vs isokinetic eccentric exercise : a direct comparison of exercise-induced muscle damage and repeated bout effect
No full textPurpose: This study compared the exercise induced muscle damage and repeated bout effect after isoload vs isokinetic eccentric supra-maximal single session. Methods: Thirty sport science male students were randomly divided in isokinetic (IK) and isoload (IL) eccentric training. Creatin kinase (CK) serum activity, muscle soreness and strength decrement measured both in dynamic and isometric modalities were recorded at baseline, immediately after and up to 4 days following 48 supramaximal IK or IL eccentric contractions. Same protocol was repeated after 4 weeks. A three-way repeated measures ANOVA was used to detect differences in dependent variables comparing group × bout × time. Results: No three-way interaction occurred in dependent variables. Bout × time resulted in a significant interaction in all dependent variables. Muscle damage markers resulted significantly altered compared to baseline up to 4 days. However, IL showed significantly greater CK, muscle soreness and strength deficit compared to IK. All parameters were significantly reduced after second compared to first bout. Difference between IL and IK after second bout was not overall significant. Conclusion: IK vs IL supra-maximal eccentric contraction is showed to have different muscle damage symptoms. Protection conferred by first bout reduced muscle damage after 4 weeks and decreased difference between IL and IK
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Brief review of the state of art in Futsal
No full textFutsal (the official name of "five side indoor football") has become very popular in recent years, and it counts more than 12 million players in over 100 countries. Futsal is played on a field of 40 × 20 m between 2 teams of 5 players, (four outfield players and the goalkeeper). Despite its rise of popularity, the number of scientific studies related to training modalities as the demands of the match or factors linked to the performance, are quite limited. This brief review aims to explore the few papers published on futsal, taking in consideration some conclusions that can be drawn from previous studies related only to futsal and indoor football players. Future studies should examine the physical demands during the matches, the variation of physical performances during the season and compare different classic training modalities to sport specific exercises, aiming to improve the current knowledge for coaching
Unilateral eccentric resistance training : a direct comparison between isokinetic and dynamic constant external resistance modalities
No full textAim of the study was to compare the effects of unilateral eccentric-only training using constant velocity vs. constant external load. Forty-seven participants were randomized in isokinetic (IK), dynamic constant external resistance (DCER) unilateral eccentric training or control groups. Knee extension 1RM and isometric, eccentric and concentric knee extensors peak torque, as well as changes in vastus lateralis fascicle pennation angle, fascicle length, muscle thickness, and quadriceps fat-free mass were measured. Both IK and DCER training consisted in 5 Ã 8 eccentric-only repetitions, 2d/w, for 6 weeks. IK and DCER training sessions were matched for total volume. After training, both IK and DCER similarly increased 1RM (respectively, +4.4 kg, CI95% 1.8–7.0 and +5.5 kg, CI95% 3.3–7.9), isometric (respectively, +34.5 N/m, CI95% 23.0–45.9 and +15.8, CI95% 5.4–26.2) and concentric peak torque (respectively, +17.0 N/m, CI95% 6.6 to +27.4 and 12.2 CI95% 2.8–21.7). IK increased eccentric peak torque significantly more than DCER (respectively, +84.2 N/m, CI95% 66.3–102.1 and +38.2 N/m, CI95% 21.9–54.4). Both IK and DCER similarly increased fascicle length (respectively, +14.7 mm, CI95% 5.4–24.0 and +14.4 mm, CI95% 5.4–23.3) and muscle thickness (respectively, +3.3 mm, CI95% 1.5–5.1, and +4.1 mm, CI95% 2.5–5.7). Matching the training volume resulted in similar adaptations comparing eccentric-only IK or DCER resistance training. Both in rehabilitation and in training practice, the use of easily available gym devices can be a good substitute for expensive and often unavailable IK devices
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