Resumos quentes e mornos…



Specific muscle adaptations in type II fibers after high-intensity interval training of well-trained runners
T. A. Kohn, B. Essén-Gustavsson, K. H. Myburgh

High-intensity interval training (HIIT) forms an important component of endurance athletes’ training, but little is known on intramuscular metabolic and fiber type adaptations. This study investigated physiological and skeletal muscle adaptations in endurance runners subjected to 6 weeks HIIT. Eighteen well-trained endurance athletes were subjected to 6 weeks HIIT. Maximal and submaximal exercise tests and muscle biopsies were performed before and after training. Results indicated that peak treadmill speed (PTS) increased (21.0 ± 0.8 vs 22.1 ± 1.2 km/h, P<0.001) and plasma lactate decreased at 64% and 80% PTS (P<0.05) after HIIT. Cross-sectional area of type II fibers tended to have decreased (P=0.06). No changes were observed in maximal oxygen consumption, muscle fiber type, capillary supply, citrate synthase and 3-hydroxyacetyl CoA dehydrogenase activities. Lactate dehydrogenase (LDH) activity increased in homogenate (P<0.05) and type IIa fiber pools (9.3%, P<0.05). The change in the latter correlated with an absolute interval training speed (r=0.65; P<0.05). In conclusion, HIIT in trained endurance runners causes no adaptations in muscle oxidative capacity but increased LDH activity, especially in type IIa fibers and in relation to absolute HIIT speed.


General strength and kinetics: fundamental to sprinting faster in cross country skiing?
T. Stöggl, E. Müller, M. Ainegren, H.-C. Holmberg

To determine relationships between general strength, maximal skiing speed (Vmax), pole and leg kinetics and kinematics, 16 male elite skiers underwent three Vmax tests in double poling, diagonal stride and V2 on a treadmill. The analyzed skiing speeds and leg and arm kinetics were among the highest ever recorded. Relationships between general strength exercises and Vmax were technique dependent. Power output in bench press and bench pull were related to Vmax in DP and diagonal stride, whereas each 1 repetition maximum was related to V2. Isometric squats were not associated with Vmax in all three techniques, whereas jump height and rate of force development during squat jump were. Analysis of kinetics and kinematics revealed that it was not exclusively the magnitude of applied forces during skiing, but the timing and proper instant of force application were major factors discriminating between faster and slower skiers. For all techniques, the faster skiers used different skiing strategies when approaching Vmax when compared with the slower skiers. General strength and power per se seem not to be major determinants of performance in elite skiers, whereas coordination of these capacities within the different and complex skiing movements seems to be the discriminating factor.


The effect of heavy strength training on muscle mass and physical performance in elite cross country skiers
T. Losnegard, K. Mikkelsen, B. R. Rønnestad, J. Hallén, B. Rud, T. Raastad

Aim: To investigate the effect of supplementing high-volume endurance training with heavy strength training on muscle adaptations and physical performance in elite cross country skiers. Eleven male (18–26 years) and eight female (18–27 years) were assigned to either a strength group (STR) (n=9) or a control group (CON) (n=10). STR performed strength training twice a week for 12 weeks in addition to their normal endurance training. STR improved 1 repetition maximum (RM) for seated pull-down and half squat (19±2% and 12±2%, respectively), while no change was observed in CON. Cross-sectional area (CSA) increased in m. triceps brachii for both STR and CON, while there was no change in the m. quadriceps CSA. VO2max during skate-rollerskiing increased in STR (7±1%), while VO2max during running was unchanged. No change was observed in energy consumption during rollerskiing at submaximal intensities. Double-poling performance improved more for STR than for CON. Both groups showed a similar improvement in rollerski time-trial performance. In conclusion, 12 weeks of supplemental heavy strength training improved the strength in leg and upper body muscles, but had little effect on the muscle CSA in thigh muscles. The supplemental strength training improved both VO2max during skate-rollerskiing and double-poling performance.


Strength training improves 5-min all-out performance following 185 min of cycling
B. R. Rønnestad, E. A. Hansen, T. Raastad

To investigate the effects of heavy strength training on the mean power output in a 5-min all-out trial following 185 min of submaximal cycling at 44% of maximal aerobic power output in well-trained cyclists. Twenty well-trained cyclists were assigned to either usual endurance training combined with heavy strength training [E+S; n=11 (♂=11)] or to usual endurance training only [E; n=9 (♂=7, ♀=2)]. The strength training performed by E+S consisted of four lower body exercises [3 × 4–10 repetition maximum (RM)], which were performed twice a week for 12 weeks. E+S increased 1 RM in half-squat (P≤0.001), while no change occurred in E. E+S led to greater reductions than E in oxygen consumption, heart rate, blood lactate concentration, and rate of perceived exertion (P<0.05) during the last hour of the prolonged cycling. Further, E+S increased the mean power output during the 5-min all-out trial (from 371 ± 9 to 400 ± 13 W, P<0.05), while no change occurred in E. In conclusion, adding strength training to usual endurance training improves leg strength and 5-min all-out performance following 185 min of cycling in well-trained cyclists.


Is there a secular decline in motor skills in preschool children?
K. Roth, K. Ruf, M. Obinger, S. Mauer, J. Ahnert, W. Schneider, C. Graf, H. Hebestreit

Current research seems to confirm a secular decline in movement skills in school children. Only few data are available for preschool children and no clear trend can be identified. In the year 2007, height, weight, and motor performance were determined in 726 preschool children [Prevention through Activity in Kindergarten Trial (PAKT)] and compared with historical samples from 1973, 1985, and 1989. There was no difference in height and weight between the samples of 1973 and 2007. Older boys of today were smaller and lighter than those of 1989. Regardless of age, PAKT children fared significantly better in standing long jump than those assessed in 1989. Compared with the sample of 1973, PAKT children did equally well in this task. There were no differences in performance in an obstacle course between children of 1989 and 2007. In balancing backwards, PAKT children performed significantly worse than those in 1985. Regarding target throwing only the PAKT 4-year-olds achieved significantly worse results than those in 1985. Therefore, in preschool children, a secular decline is only evident in some, but not all, motor skills, which may indicate a change in behavior activity over the last decades.


Impact of intense training and rapid weight changes on salivary parameters in elite female Taekwondo athletes
M.-L. Tsai, M.-H. Ko, C.-K. Chang, K.-M. Chou, S.-H. Fang

The aim of this study is to examine the cumulative effects of prolonged intensive training with or without rapid weight changes (RWC) on salivary parameters of elite female Taekwondo (TKD) athletes. Ten elite female Taiwanese TKD athletes (ages: 21.3 ± 1.2 years of age, Ht 164.4 ± 5.6 cm) volunteered to participate in this study. Resting saliva samples were collected at 28-, 14-, 7-, and 1 day before and 1-, 7-, 21 days after a national competition. The levels of salivary immunoglobulin A (sIgA), cortisol, and lactoferrin were measured. In analyzing the anthropometric data, we found that a significant proportion (50%) of elite female TKD athletes had RWC shortly before and after a national competition. The participants were allocated either to the RWC or to the non-RWC group according to their weight change profiles. Our results showed that levels of sIgA and cortisol of athletes with RWC were significantly modulated during the study period. However, athletes without RWC only showed reduced lactoferrin after competition. The results presented here demonstrate that intensive training in combination with RWC affects the mucosal immunity and disrupts the cortisol stress response of elite female TKD athletes.


Stress-related hormonal and psychological changes to official youth Taekwondo competitions
S. Chiodo, A. Tessitore, C. Cortis, G. Cibelli, C. Lupo, A. Ammendolia, M. De Rosas, L. Capranica

The aim of this study was to evaluate the effects of an official Taekwondo competition on the heart rate (HR), salivary α-amylase (sA-A), salivary free cortisol (sC), and Profile of Mood States (POMS) in 10 young male (14±0 years) and six female (13±1 years) athletes. POMS and hormones were measured 15 min before and directly after the competition. During the recovery phase (30 and 90 min), sA-A and sC were also measured. HR measured during the competition was expressed as a percentage of individual’s maximal heart rate (%HRmax) to evaluate the intensity of exercise. During the competition, athletes spent 65% of the time working at HR>90% of individuals HRmax. A significant increase (P<0.0001) in sA-A (115%) was observed at the end of the match. At 30 min of recovery, sA-A returned to the pre-competition level. The peak sC values were observed at 30 min of recovery (P<0.001), returning to the pre-competition level at 90 min of recovery. A gender difference (P=0.01) emerged only for sC, although a similar trend was observed for female and male athletes. Significantly higher post-match scores emerged for Anger-hostility (pre: 6.1±1.1, post: 11.2±1.9; P=0.03) and Depression-dejection (pre: 4.5±0.5, post: 10.2±1.9; P=0.006), whereas the reverse picture was observed for Vigour-activity (pre: 23.2±1.2, post: 16.3±1.7; P=0.0006). Taekwondo competition results in temporary changes in the stress-related parameters measured in this study. The present findings suggest that this experimental paradigm can represent a useful model for further research on the effects of various stressors (i.e., training and competition) in Taekwondo athletes of different levels (i.e., novice, international).


Predictors of pre- and post-competition affective states in male martial artists: a multilevel interactional approach
E. Cerin, A. Barnett

The aims of this study were to examine (a) the effects of competition-related and competition-extraneous concerns on affective states; (b) the relationships of primary and secondary appraisal with affective states and (c) the main and moderating effects of personality traits on pre- and post-competition affects. Thirty-nine male elite martial artists were assessed on 12 affective states, concerns and dimensions of primary and secondary appraisal at five random times a day across 1 week before and 3 days after a competition. On the competition day, they were assessed 1 h before and immediately after the contest. Competitive trait anxiety, neuroticism and extraversion were measured at the start of the study. The competition was the most significant and stressful event experienced in the examined period and had a pervasive influence on athletes’ affective states. All examined appraisal and personality factors were somewhat associated with pre- and post-competition affective states. Competitive trait anxiety was a key moderator of the relationship between cognitive appraisal and affective states. This study supports the idea that cognitive appraisal and situational and personality factors exert main and interactive effects on athletes’ pre- and post-competition affects. These factors need to be accounted for in planning of emotion regulation interventions.


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