International SportMed Journal - Volume 13, Issue 1, 2012
Volume 13, Issue 1, 2012
Source: International SportMed Journal 13, pp 1 –7 (2012)More Less
Chronic endurance training increases an athlete's aerobic capacity and results in improved cardiocirculatory work economy, maximum performance, and enhanced oxygen uptake. The extent of the adaptation depends on individual factors such as frequency, intensity, and duration of training, muscle fibre type, and genetics. The functional range of heart rate, cardiac contractility, diastolic function, and blood pressure increases, while cardiocirculatory work is more economical, and maximum oxygen uptake (VO2max) is improved.
Symmetric enlargement of the heart begins when endurance training exceeds individual functional limits, resulting in both left and right ventricular and atrial hypertrophy in response to the increased workload placed on the heart. Routinely examined by echocardiography, the myocardial hypertrophy is related to the increase in the interior end-diastolic volume. In contrast to pathological forms of cardiac wall hypertrophy, the mass / volume ratio, and therefore the maximum systolic wall stress remains constant. In addition, functional and structural changes occur in the vascular system.
Cardiac adaptations to exercise, including function and size of the heart, regress in healthy people who become inactive and have no structural heart disease.
Source: International SportMed Journal 13, pp 8 –17 (2012)More Less
Background: Footprint analysis is one of the methods that can be used to diagnose foot pathologies. Football is usually seen as a team sport whereby players attempt to move the ball, primarily with the action of the foot to an opponent's goal area to score. Players have a high risk of injury in this sport. Research question: The aim of this study is to evaluate the sole morphology of professional football players. Type of study: Cross-sectional study. Methods: One hundred and ten professional Turkish football players and healthy volunteers participated in the study. Footprint images of both feet were obtained by means of a specially designed scanner system. By means of this system images of the right and left static weight-bearing footprints were acquired, firstly with 50% of the body weight on each foot and then with 90% of the body weight (standing straight, single-limb, weight-bearing stance) were obtained. Measurements were performed using the AutoCAD 2004 software. Results: Arch angle, Chippaux-Smirak, Staheli, arch length, arch, footprint, truncated arch were calculated for both left and right feet. In the 50% weight-bearing stance of the right foot, the arch angle and Chippaux-Smirak, Staheli, footprint, and truncated arch indices were significantly higher in the professional football players than in the controls. For the left foot, only the arch angle and Staheli index were significantly higher in the professional football players compared with the controls. In the 90% weight-bearing stance of the right foot, the arch angle and truncated arch index were significantly higher in the professional football players than in the controls. For the left foot, the arch angle, and the arch length, footprint, and truncated arch indices were significantly higher in the football players compared with the non-athlete controls. Conclusion: Foot morphology of football players may assist in the design of the best football boots for the sport.
Effects of consecutive 7-day high- versus moderate-intensity training on endurance determinants and muscle damage in basketball players : original research articleSource: International SportMed Journal 13, pp 18 –28 (2012)More Less
Background: High-intensity interval training (HIT) on VO2peak, peak aerobic power output and 5km time trial performance was suggested to be an efficient training strategy, and consecutive 3-day per week training for 3 weeks could provide similar training effects with non-consecutive days. The effects of consecutive 7-day HIT is still not clear. Research question: To compare the consecutive 7-day training effects of HIT versus moderate-intensity continuous training (MCT), matched for training distance, on the endurance parameters of velocity of 4mmol·L-1 lactate threshold (4-LT), running economies (REs), maximal oxygen uptake (VO2max), velocity associated with VO2max (vVO2max) and plasma activity of creatine kinase (CK) in young basketball players. Type of study: Randomised experimental research was used. Methods: Eighteen male basketball players were randomly divided into HIT (n = 10) or MCT group (n = 8). Subjects conducted consecutive 7-days of treadmill training performing either HIT (7 repetitions, 2-min bouts at 90% VO2max, 1-min rest intervals) or MCT (continuous, 20.8 ± 1.0 min at 65% VO2max). Pre- and post-training, the 4-LT, REs at fixed speed of 2.0, 2.5 and 3.0 m·s-1, VO2max, vVO2max, and CK activity of subjects were measured. Results: After training, the HIT group significantly improved 4-LT (3.2 ± 0.4 to 3.5 ± 0.5 m·s-1, P < 0.05), REs (10.4-11.5%, P < 0.05), and vVO2max (4.1 ± 0.5 to 4.5 ± 0.8 m·s-1, P < 0.05). The HIT group also showed significant increase in the activity of CK (148.1 ± 47.3 to 302.6 ± 68.2 U·L-1, P < 0.05). Conclusions: When training volume is matched, consecutive 7-day of HIT is more efficient than MCT for improving endurance determinants and has small extent of muscle damage for basketball players.
100m and 200m front crawl performance prediction based on anthropometric and physiological measurements : original research articleAuthors: Victor Machado Reis, Antonio Jose Silva, Giovanni Silva Novaes, Victor Machado Reis, Antonio Jose Silva, Giovanni Silva Novaes, Victor Machado Reis, Antonio Jose Silva, Andre Luiz Carneiro, Daniel Almeida Marinho, Tiago Manuel Barbosa, Andre Luiz Carneiro, Daniel Almeida Marinho and Tiago Manuel BarbosaSource: International SportMed Journal 13, pp 29 –38 (2012)More Less
Background: The identification of the variables that are able to predict swimming performance is one of the main purposes of the "swimming science" community. Research question: The aims of the study were: (i) to compare the anthropometric and physiological profiles of 100m and 200m front crawl swimmers and; (ii) to identify anthropometric and physiological variables that account for the prediction of the swimming performance at the 100m and 200m front crawl events. Methods: Twenty-six male swimmers were divided in two groups (12 for 100m group and 14 to 200m group). The swimmers' personal best performance for the 100m and the 200m front crawl was converted to FINA points. The subjects performed a graded swimming test and an all-out test (100 or 200m maximal swims) in different days, in which physiological measures were evaluated. Forward step-by-step linear regression models were computed to predict swimming performance. The subjects' performances (season best and all-out test) were taken as dependent variables. The age, physiological and anthropometric measures were selected as independent variables. Results: Anthropometric and physiological profiles of 100 and 200m swimmers are different and the mean oxygen uptake during exercise combined with training experience may explain 200m front crawl best season performance with a high precision (≈2% error). The models computed were able to predict from 44 % (i.e. 200m all-out bout) to 61 % (i.e. 200m season best) swimming performance. Predictive power of the models was less accurate in the 100m event (error > 10%). Conclusions: The authors conclude that the extent to which the physiological and anthropometric variables combine to predict performance probable is group-specific.