The effect of different exercise-testing protocols on atrial natriuretic peptide.

The aim of this study was to examine and to compare alterations in the secretion of atrial natriuretic peptide (ANP) during different exercise-testing protocols in moderately trained men. Fifteen healthy male physical education students were studied (mean age 22·3 ± 2·5 years, training experience 12·3 ± 2·5 years, height 1·80 ± 0·06 m, weight 77·4 ± 8·2 kg). Participants performed an initial graded maximal exercise testing on a treadmill for the determination of VO(2max) (duration 7·45-9·3 min and VO(2max) 55·05 ± 3·13 ml kg(-1) min(-1) ) and were examined with active recovery (AR), passive recovery (PR) and continuous running (CR) in random order. Blood samples for plasma ANP concentration were taken at rest (baseline measurement), immediately after the end of exercise as well as after 30 min in passive recovery time (PRT). The plasma ANP concentration was determined by radioimmunoassay (RIA). The results showed that ANP plasma values increased significantly from the rest period to maximal values. In the short-term graded maximal exercise testing the ANP plasma values increased by 56·2% (44·8 ± 10·4 pg ml(-1) versus 102·3 ± 31·3 pg ml(-1) , P<0.001) and in the CR testing the ANP levels increased by 29·2% (44·8 ± 10·4 pg ml(-1) versus 63·3 ± 19·8 pg ml(-1) , P<0.001) compared to the baseline measurement. Moreover, the values of ANP decreased significantly (range 46·4-51·2%, P<0.001) in PRT after the end of the four different exercise modes. However, no significant difference was evident when ANP values at rest and after AR and PR were compared. It is concluded that the exercise testing protocol may affect the plasma ANP concentrations. Particularly, short-term maximal exercise significantly increases ANP values, while the intermittent exercise form of active and passive recovery decreases ANP concentrations.

Isokinetic strength and joint mobility asymmetries in oarside experienced oarsmen.

The purpose of the present study was to investigate oarside and nonoarside lower extremity asymmetries in isokinetic strength and joint mobility of port and starboard oarsmen. Peak torques of right and left extensors and flexors were measured on isokinetic dynamometer at angular velocities of 60 and 180°·s-1 in 12 starboard (n = 12; training age 5.55 ± 0.52 years) and 14 port (n = 14; training age 6.09 ± 0.95 years) well-trained male rowers. Mobility of the hip, knee, and ankle joints was measured using the Myrin flexometer, a modification of the Leighton flexometer. The findings indicate that ports had a significantly higher peak torque in oarside right knee extensors at 60°·s-1 (p < 0.001) and 180°·s-1 (p < 0.01) compared to in the nonoarside left knee extensors. In a respective manner, starboards had a higher peak torque in left knee extensors at 60°·s-1 (p < 0.05) and 180°·s-1 (p < 0.05) compared to the right side. Right flexors peak torque was significantly higher in ports compared to that in starboards at 60°·s-1 (p < 0.05) and 180°·s-1 (p < 0.01). No significant difference between port and starboards in left knee flexors at either angular velocity was found. Both port and starboards exhibited a significantly higher hip (p < 0.01) mobility in oarside compared to in nonoarside. We conclude that sweep rowers develop a significantly higher flexion knee peak torque and hip mobility depending on oarside. Strength and mobility abnormalities may provide information for training and rehabilitation. Strengthening and stretching training programs to compensate for potential strength and mobility imbalance and thereby reducing the occurrence of injuries may be designed.

Increased oxidative stress blood markers in well-trained rowers following two thousand-meter rowing ergometer race.

High-intensity exercise is associated with increased oxidative stress. Rowing is very demanding requiring maintenance of high power mostly produced from aerobic metabolism. The present study aimed at investigating selective blood oxidative stress markers in response to a rowing race simulation test, consisting of 2,000 m maximal effort on a rowing ergometer, in well-trained male rowers during the preseason preparatory training period. Mean time for the 2,000-m trial was 409.4 +/- 4.0 seconds, and heart rate at 2,000 m was 198 +/- 1 b x min (mean +/- SEM). Blood lactate concentration was 11.2 +/- 0.6 mmol x L. Postexercise whole blood lysate oxidized glutathione (GSSG) concentration significantly increased (19%), whereas reduced glutathione (GSH) concentration remained unchanged, resulting in an overall decreased postexercise GSH:GSSG ratio (20%). Postexercise serum thiobarbituric acid-reactive substance concentration and protein carbonyls increased by 45 and 70%, respectively, as compared with the pre-exercise levels. Likewise, postexercise catalase activity (105%) and total antioxidant capacity (9%) significantly increased. In agreement with other studies, our data illustrate that a 2,000-m rowing ergometer race induces significant blood oxidative stress despite the rowers' high training status. In scheduling an evaluation rowing test or a competition, coaches should allow sufficient recovery time elapsed between the test and the last intensive training session. The 2,000-m rowing performance appears to be a suitable test to assess oxidative stress in rowers and could potentially serve as a model to study oxidative damage in sports science.