Giorgos Paradisis

An Evaluation of Tests of Anaerobic Power and Capacity

0799 A variety of testing procedures have been employed to quantify anaerobic power and capacity including maximal oxygen deficit and dept, wingate test, vertical jump tests, staircase test, and exhaustive constant load tests. Although the validity of these tests is questionable most of them have the ability to evaluate anaerobic capacity and distinguish between power athletes and endurance trained subjects. Critical velocity (CV) field test has been recently introduced as a measure of aerobic and anaerobic capacity. Comparison studies between anaerobic capacity derived from CV (CVac) and other traditional anaerobic exercise estimates are scarce. PURPOSE: To evaluate CVac against Wingate anaerobic parameters and another anaerobic field test (6 × 35m interspersed with 10sec recovery), running anaerobic sprint test (RAST). METHODS: Eleven active men and women mean (± SD) age, height, weight and %body fat were 22.27 ± 1.49yr, 172.5 ± 4.8cm, 67.27 ± 6.61kg and 14.3 ± 5.6 performed on separate days: a 30sec maximal cycle ergometer test (wingate test), the RAST and the CV test. Anaerobic capacity estimate of CV test was assessed from the regression of the distance run (distance limit; DL) versus the time limit (TL) at 3 exhaustive running velocities on the treadmill and the resulting equation DL = a+b(TL), where a is considered to be CVac. RESULTS: The results indicated that CVac was not significantly (p>0.05) correlated with wingate peak power (r = 0.27), mean power (r = 0.24) and the fatigue index (r = 0.15). The absent of significant correlation was also noticed between CVac and RAST peak power (r = 0.27) and average power (r = 0.19). Significant correlations (p<0.01) although presented between Wingate and RAST peak power (r = 0.82) and mean power (r = 0,75). CONCLUSIONS: The findings of the present study: a) do not support the use of CVac as an indirect indicator of anaerobic capabilities and b) RAST field test can successfully replace the laboratory based Wingate test as an estimate of anaerobic power and capacity.

Anthropometric and kinematic influences on release speed in men's fast-medium bowling.

The main aim of this study was to identify significant relationships between selected anthropometric and kinematic variables and ball release speed. Nine collegiate fast-medium bowlers (mean - s : age 21.0 - 0.9 years, body mass 77.2 - 8.1 kg, height 1.83 - 0.1 m) were filmed and reconstructed three-dimensionally. Ball release speeds were measured by a previously validated Speedchek™ Personal Sports Radar (Tribar Industries, Canada). Relationships between selected anthropometric variablesand ball release speed and between kinematic variables and ball release speed were investigated using Pearsons product-moment correlation coefficients ( r ). A significant relationship was found between the horizontal velocity during the pre-delivery stride ( r = 0.728, P ≪ 0.05) and ball release speed (31.5 - 1.9 m·s -1 ). We believe that the high correlation was due to the bowlers using techniques that allowed them to contribute more of the horizontal velocity created during the run-up to ball release speed. We also found that the angular velocity (40.6 - 3.4 rad·s -1 ) of the right humerus had a low correlation ( r = 0.358, P > 0.05) with ball release speed. Although the action of the wrist was not analysed because of an inadequate frame rate, we found high correlations between ball release speed and shoulder-wrist length (661 - 31 mm; r = 0.626, P ≪ 0.05) and ball release speed and total arm length (860 - 36 mm; r = 0.583, P ≪ 0.05). We conclude that the variance in release speed within this group may be accounted for by the difference in radial length between the axis of rotation at the glenohumeral joint and the release point.

Kinematic and postural characteristics of sprint running on sloping surfaces

The aim of this study was to identify the kinematic and postural characteristics associated with sprint running on uphill and downhill slopes of 3° and on a horizontal surface. Eight male physical education students were filmed while sprinting maximally on an uphill-downhill platform under each of three conditions: (a) uphill at 3°, (b) downhill at 3° and (c) horizontal. Running speed, step rate, step length, step time, contact time, flight time and selected postural characteristics of the step cycle were analysed. Running speed was 9.2% faster ( P < 0.05) during downhill and 3.0% slower ( P < 0.05) during uphill compared with horizontal sprint running. During downhill and uphill sprint running, step length was the main contributor to the observed changes in running speed. It increased by 7.1% ( P < 0.05) for downhill sprint running and was associated with significant changes in posture at touchdown and take-off. During uphill sprint running, step length decreased by 5.2% ( P < 0.05), which was associated with significant changes in posture and reduced flight distance. Given the interaction between the acute changes in step length and posture when sprinting on a sloping surface, our findings suggest that such changes in posture may detract from the specificity of training on such surfaces. The chronic effects of training on such slopes on the kinematics and posture of horizontal sprint running are currently unclear.

The effects of sprint running training on sloping surfaces.

The aim of this study was to examine the effects of sprint running training on sloping surfaces (3°) on selected kinematic and physiological variables. Thirty-five sport and physical education students were randomized into 4 training groups (uphill-downhill, downhill, uphill, and horizontal) and a control group, with 7 participants in each group. Pre- and posttraining tests were performed to examine the effects of 6 weeks of training on the maximum running speed at 35 m, step rate, step length, step time, contact time, eccentric and concentric phase of contact time, flight time, selected posture characteristics of the step cycle, and peak anaerobic power performance. Maximum running speed and step rate were increased significantly (p < 0.05) in a 35-m running test after training by 0.29 m·s−1 (3.5%) and 0.14 Hz (3.4%) for the combined uphill-downhill group and by 0.09 m·s−1 (1.1%) and 0.03 Hz (2.4%) for the downhill group, whereas flight time shortened only for the combined uphill-downhill training group by 6 milliseconds (4.3%). There were no significant changes in the horizontal and control groups. Overall, the posture characteristics and the peak anaerobic power performance did not change with training. It can be suggested that the novel combined uphill-downhill training method is significantly more effective in improving the maximum running velocity at 35 m and the associated horizontal kinematic characteristics of sprint running than the other training methods are.

Analysis of selected kinematic and physiological performance determinants during incremental testing in elite swimmers.

This study examined the relationships between selected kinematic and physiological parameters and their influence on performance during incremental exercise in elite swimmers competing at the international level. Eleven men and ten women (all specialized in 200-m events) performed an incremental 7 × 200-m test in their specialized stroke. Stroke rate (SR), stroke length (SL), velocity (V), and blood lactate concentration (BLa) were measured for each 200 m. In addition to the cross-sectional group design, the longitudinal performance of a male swimmer was evaluated by 4 tests during a period of 20 weeks. Stroke rate increased and SL decreased with V, regardless of the age, stroke, or gender of the swimmer. Statistically significant correlations were found between SR and V (p < 0.01; r = 0.66 to 0.99), SR and SL (p < 0.01; r = −0.78 to -0.99), SL and V (except for womens freestyle and breaststroke) (p < 0.01; r = −0.67 to -0.98), and BLa and V (p < 0.01; r = 0.7 to 0.96). Changes in SR and SL were not affected by changes in BLa. Similar velocities were produced with different combinations of SR and SL. The fastest times reached in the test were generally slower than expected, and the performance in the test was not associated with competition performance. The case study revealed similar results to those of the group. The test used in this study was informative with respect to identifying the most economical and effective stroke kinematics combination for slow to submaximal velocities. It is possible that the swimming speeds were not maximal in the final 200-m swim because of cumulative fatigue, which is a major limitation for assessing race pace. An additional test that produces velocities similar to those used in competitions would be more useful for the purpose of providing optimal kinematic information specific to racing speeds, which would facilitate performance improvement through regular monitoring in training.

Effects of static and dynamic stretching on sprint and jump performance in boys and girls.

Abstract Paradisis, GP, Pappas, PT, Theodorou, AS, Zacharogiannis, EG, Skordilis, EK, and Smirniotou, AS. Effects of static and dynamic stretching on sprint and jump performance in boys and girls. J Strength Cond Res 28(1): 154–160, 2014—The aim of this study was to investigate the acute effects of static (SS) and dynamic stretching (DS) on explosive power, flexibility, and sprinting ability of adolescent boys and girls and to report possible gender interactions. Forty-seven active adolescent boys and girls were randomly tested after SS and DS of 40 seconds on quadriceps, hamstrings, hip extensors, and plantar flexors; no stretching was performed at the control condition. Pretreatment and posttreatment tests examined the effects of stretching on 20-m sprint run (20 m), countermovement jump (CMJ) height, and sit and reach flexibility test. In terms of performance, SS hindered 20 m and CMJ in boys and girls by 2.5 and 6.3%, respectively. Dynamic stretching had no effect on 20 m in boys and girls but impaired CMJ by 2.2%. In terms of flexibility, both SS and DS improved performance with SS being more beneficial (12.1%) compared with DS (6.5%). No gender interaction was found. It can therefore be concluded that SS significantly negates sprinting performance and explosive power in adolescent boys and girls, whereas DS deteriorates explosive power and has no effect on sprinting performance. This diversity of effects denotes that the mode of stretching used in adolescent boys and girls should be task specific.

Reliabilities of leg and vertical stiffness during treadmill running

The aim of this study was to determine the intra-participant variabilities (i.e. intra-day and inter-day reliabilities) in leg and vertical stiffness, as well as related kinematic parameters, during treadmill running using the sine-wave method. Twenty-two healthy men ran on a treadmill at 4.44 m/s, and the flight and contact times were measured with a high-speed video camera. Three 30-s running bouts with 2-min inter-bout rests were performed to examine the intra-day reliability, and single 30-s running bouts on three separate days with 24- to 48-h inter-bout intervals were performed to examine the inter-day reliability. The reliability statistics included repeated-measure analyses of variance, average inter-trial correlations, intra-class correlation coefficients (ICCs), Cronbachs α reliability coefficient, and the coefficient of variation. Both leg and vertical stiffness produced high ICCs within 0.972 and 0.982, respectively, and between 0.922 and 0.873 days, respectively. High values were also observed for all of the reliability coefficients. Similar results were found regarding contact time, flight time, step length, and step rate. It was concluded that the measurements of leg and vertical stiffness, as well as related kinematic parameters, obtained using the sine-wave method during treadmill running at 4.44 m/s, were highly reliable, both within and across days.

Multi-Stage 20-m Shuttle Run Fitness Test, Maximal Oxygen Uptake and Velocity at Maximal Oxygen Uptake

Abstract The multi-stage 20-m shuttle run fitness test (20mMSFT) is a popular field test which is widely used to measure aerobic fitness by predicting maximum oxygen uptake (VO2 max) and performance. However, the velocity at which VO 2 max occurs (vVO 2 max) is a better indicator of performance than VO 2 max, and can be used to explain inter-individual differences in performance that VO 2 max cannot. It has been reported as a better predictor for running performance and it can be used to monitor athletes’ training for predicting optimal training intensity. This study investigated the validity and suitability of predicting VO2max and vVO2max of adult subjects on the basis of the performance of the 20mMST. Forty eight (25 male and 23 female) physical education students performed, in random order, a laboratory based continuous horizontal treadmill test to determine VO2max, vVO 2 max and a 20mMST, with an interval of 3 days between each test. The results revealed significant correlations between the number of shuttles in the 20mMSFT and directly determined VO 2 max (r = 0.87, p<0.05) and vVO 2 max (r = 0.93, p<0.05). The equation for prediction of VO 2 max was y = 0.0276x + 27.504, whereas for vVO 2 max it was y = 0.0937x + 6.890. It can be concluded that the 20mMSFT can accurately predict VO 2 max and vVO 2 max and this field test can provide useful information regarding aerobic fitness of adults. The predicted vVO 2 max can be used in monitoring athletes, especially in determining optimal training intensity.

Assessment of accuracy, reliability and force measurement errors for a tethered swimming apparatus

Researchers frequently use purpose-built devices to calculate propulsive forces during tethered swimming. Although such devices are subject to force measurement errors, no specific methods have been suggested in the swimming literature for the estimation of these errors. The purpose of this study was to access the accuracy and reliability of a portable device that is used to measure propulsive forces in tethered swimming, and to estimate the errors caused by hysteresis, sensitivity and linearity. The force values recorded during a maximum front crawl test of an international level swimmer were used to provide an example of the extent to which measurement errors could affect the values collected during a tethered swimming study. The calculations revealed small and acceptable errors. When summing the errors from all sources, the total errors affecting the minimum, average and peak forces recorded during the case study were 1.15%, 0.94% and 0.86% respectively. It is recommended that investigators always calculate and report such errors for tethered swimming studies. The methods used in the present study are reasonably simple and not time-consuming, and could be used when assessing errors for similar tethered swimming devices.

Leg and vertical stiffness (a)symmetry between dominant and non-dominant legs in young male runners.

Biomechanical findings show that running is asymmetric in many kinetic properties. Running stiffness is a vital kinetic property of yet unknown pattern of lateralization. The aim of this study was to examine the degree and variability of lower limb dominance specific asymmetry of running in terms of leg stiffness, vertical stiffness, contact time, flight time, maximal ground reaction force during contact, vertical displacement of the center of mass, and change in leg length. Leg and vertical stiffness was estimated by the sine-wave method in 22 young males during treadmill running at 4.44 m/s. Lower limb dominance was determined by the triple-jump test. Asymmetry was expressed as dominant - non-dominant, and indexed by the absolute asymmetry index. Significant asymmetry was found only in flight time (3.98%) and in maximal ground reaction force (1.75%). The absolute asymmetry index ranged from 1.8% to 6.4%, showed high variation between subjects (0-31.6%), and differentiated among the 7 analyzed variables. Leg and vertical stiffness in treadmill running of moderate pace (4.44 m/s) should be considered symmetric.