Christos S. Riganas

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 VO2max (duration 7·45–9·3 min and VO2max 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

Riganas, CS, Vrabas, IS, Papaevangelou, E, and Mandroukas, K. Isokinetic strength and joint mobility asymmetries in oarside experienced oarsmen. J Strength Cond Res 24(11): 3166-3172, 2010-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.

Cardiorespiratory and metabolic alterations during exercise and passive recovery after three modes of exercise.

Mandroukas, A, Heller, J, Metaxas, TI, Sendelides, T, Riganas, C, Vamvakoudis, E, Christoulas, K, Stefanidis, P, Karagiannis, V, Kyparos, A, and Mandroukas, K. Cardiorespiratory and metabolic alterations during exercise and passive recovery after three modes of exercise. J Strength Cond Res 25(6): 1664-1672, 2011—The objective of this study was to investigate the potential variations in cardiorespiratory and metabolic parameters and running performance among 3 modes of exercise of the same duration, namely, intermittent running with active recovery (AR) or passive recovery (PR) and continuous running (CR) and whether these variations could affect passive recovery time (PRT). Fifteen male physical education students with a subspecialty in soccer were studied (mean age 22.3 ± 2.5 years, training experience 12.3 ± 2.5 years) in the middle of the playing season. The results showed that during exercise, the highest heart rate (HR) and &OV0312;O2 values were observed in CR, whereas the lowest values in PR followed by AR. Blood lactate (BLa) concentration was higher in PR by 38% compared to that in AR (p < 0.05). The exercise duration was similar between PR and AR tests and longer than in CR. With regard to PRT, the highest HR (186 ± 9 b·min−1), &OV0312;O2 (55.5 ± 5.2 ml·kg−1·min−1), and BLa (5.1 ± 1.7 mmol·L−1) values were found in CR. No differences in HR and &OV0312;O2 between PR and AR were detected. However, despite the differences in BLa concentration between AR and PR during exercise, the PRT BLa values between these 2 exercise modes were not different. Among the 3 running protocols, only CR appeared to have fully challenged the cardiorespiratory system inducing maximal HR and &OV0312;O2 responses during exercise and high BLa values in PRT, yet these responses were not associated with better exercise performance compared to intermittent running. Therefore, intermittent exercise, regardless of implementing passive or active interval, might be the preferable exercise mode particularly in activities extended over 30 minutes.

Energy cost during running and cycling in climbers and mountain bike riders

IntroductionRunning economy (RE) is defined as the energy cost (EC) for a given velocity of submaximal running and it is determined by measuring the steady condition consumption of oxygen (VO2) and the respiratory exchange ratio (RER) (Saunders et al., 2004). Runners who have a better EC, use less energy and less oxygen ,at the same speed, than runners with poor running economy. There is a strong association between EC and distance running performance, with EC being a better predictor of performance than maximal oxygen uptake (VO2max) in elite runners, who have a similar VO2max (Saunders et al., 2004). A number of physiological and biomechanical factors seem to influence RE and EC, including temperature, heart rate, ventilation, VO2max, age, gender, body mass, muscle fiber type distribution and other biomechanical variables (Morgan et al., 1989; Daniels & Daniels, 1992; Morgan & Craib, 1992; Pate et al., 1989; Saunders et al., 2004). Lower running economy is a result of neuromuscular fitting shortage and the disability of elastic energy utilization. Contrarily, higher running economy is due to better neuromuscular coordination and coordinated movement and it leads to a greater performance. Metabolic adaptations in muscles, with increased density of muscle mitochondria, oxidative enzymes and better ability to store and utilize elastic energy by the muscles lead to a lower EC of running (Saunders et al., 2004).None of the athletes seems to consume 22% more oxygen than high level runners at the same steady condition speed (Costiel, 1986). Comparing high level runners with moderately trained runners, the results show better EC for the first group (Morgan et al., 1992). Long distance runners also present better economy, than semi-distance and sprint runners. It leads to a greater EC, at a 150 to 300 Kcal, in a marathon race for elite runners, compared to moderately trained runners (Conley et al., 1980; Daniels et al., 1992). EC is also correlated with muscle tissue apportion. Cyclists with better energy cost have a greater amount of type I fibers in leg muscles. It is calculated that performance factor of fibers type I is 27 %, and type II is 13% (Coyle et al., 1992, 1999).It has been suggested that a higher percentage of slow-twitch muscle fibres is associated with better running economy. (Bosco et al., 1987; Williams et al., 1987). The relationship between EC and performance is well established for running (Cavanagh & Kram, 1989), walking (Minetti et al., 1995) and cycling (Hagberg et al., 1981). A Treadmill running and cycle ergometry comparison showed similar parameters of the VO2 responses, except for the VO2 slow component, which was significantly greater for cycling than for running (Carter et al., 2000). Oxygen uptake seems to be lower and blood lactate higher for a brief period of intense nonsteady state cycling as compared to uphill running .On the contrary, anaerobic energy cost is higher for cycling, although in terms of work efficiency those two can be similar (Scott et al., 2006). Also metabolic cost of submaximal cycling in different pedalling rates rises in a linear regression with speed and pedal rate (McDaniel et al., 2002). The majority of studies indicate that runners achieve a higher VO2max on treadmill, whereas cyclists can achieve a VO2max value in cycle ergometry similar to that in treadmill running (Millet et al., 2009). An increase of energy cost along with exercise duration had already been observed for prolonged exercises such as running (Davies et al., 1986) and cycling (Lepers et al., 2000). All mountain bike riders (MTB) seem to have similar physical characteristics with climbers (Impellizseri & Marcora, 2007).Although in bibliography there are reports about studies, that examined energy cost and economy of cycling and running, there is no report concerning the comparison in the energy cost of climbers and MTB riders. The aim of the present study was to evaluate and compare the cardiorespiratory performance and energy cost in trained climbers and MTB athletes. …