A Semi-Tethered Test for Power Assessment in Running

Mechanics and Energetic Analysis of Rowing with Big Blades with Randall Foils

Empirical observations support that the addition of a plastic strip - also known as Randall foils - on the top edge of a rowing blade improves rowing efficiency during the cycle propulsive phase. The aim of the current study was to analyze the effect of using big blades with and without Randall foils on rowing performance. Twenty experienced rowers performed two 90 s tethered rowing bouts (with and without Randall foils) to assess their impact on force production and physiologic variables. All tests were randomized and a repeated measure design was used to compare experimental conditions. Higher values of peak and mean peak forces (479.4±134.7 vs. 423.2±153.0, d=0.83 and 376.5±101.4 vs. 337.1±113.3 N, d=0.68), peak oxygen uptake (47.9±7.5 vs. 45.3±7.3 mL∙kg-1∙min-1, d=0.19), peak blood lactate concentration (7.9±1.6 vs. 6.9±1.7 mmol∙L-1, d=0.16), blood lactate increasing speed (0.08±0.01 vs. 0.07±0.06 [(mmol·L-1)·s-1], d=0.27) and lactic anaerobic energy (27.4±7.9 vs. 23.4±8.1 kJ, d=0.23) were found for big blades with vs. without Randall foils, p<0.05. The current data suggest that the Randall foils can positively affect rowing performance.

Reliability and Validity of a New Portable Tethered Sprint Running Test as a Measure of Maximal Anaerobic Performance

Limmer, M, Berkholz, A, de Marées, M, and Platen, P. Reliability and validity of a new portable tethered sprint running test as a measure of maximal anaerobic performance. J Strength Cond Res 34(8): 2197-2204, 2020-The purposes of this study were to develop a new portable tethered sprint running (PTSR) test for field-based anaerobic performance testing with restricted spatial conditions and the logistical challenge of carrying test equipment, and to determine reliability of the PTSR test. For validity, performance measures were compared with the cycle ergometer Wingate Anaerobic Test (WAnT) power outputs. Twelve recreationally active men and women (24.3 ± 1.6 years; 1.77 ± 0.07 m; 73.3 ± 12.5 kg) performed one familiarization trial followed by 3 randomly assigned experimental 60-second all-out effort trials consisting of one WAnT and 2 PTSR tests. All trials were performed in a randomized order on different days separated by at least 48 hours. Heart rate (HR) and maximum blood lactate concentration were recorded for each experimental trial to determine the physiological responses to the maximal efforts. Correlation coefficients indicated significant relationships between mean force (MF) and peak force (PF) in the PTSR test and mean power (MP) (r = 0.651, p = 0.022) and peak power (PP) (r = 0.877, p = 0.002) in the WAnT, but not for the fatigue index (r = 0.280, p = 0.379). In addition, both PTSR trials showed no significant differences (p > 0.05) between trials and a high reliability for the performance variables MF (intraclass correlation coefficient [ICC] = 0.98, coefficient of variation [%CV] = 7.7), PF (ICC = 0.98, %CV = 8.4), and HR (ICC = 0.92, %CV = 3.1). In conclusion, our results suggest that despite insufficient stimulation of anaerobic metabolism in some subjects resulting from poor implementation of test instructions, the PTSR is a reliable and valid test for an easy and practical assessment of maximal anaerobic performance under different field conditions.

Corresponding Assessment Scenarios in Laboratory and on-Court Tests: Centrality Measurements by Complex Networks Analysis in Young Basketball Players

Besides technical and tactical aspects, basketball matches involve high aerobic and anaerobic capacities, conferring the final performance of a team. Thus, the evaluation of physical and technical responses is an effective way to predict the performance of athletes. Field and laboratory tests have been used in sports. The first involving high ecological validity and low cost, and the second, greater control and accuracy but not easy application, considering the different preparation phases in a season. This study aimed, through complex networks analysis, to verify whether centrality parameters analysed from significant correlations behave similarly in distinct scenarios (laboratory and on-court), emphasizing aerobic and anaerobic physical parameters and technical performances. The results showed that, in a compelling  analysis involving basketball athletes, the studied centralities (degree, betweenness, eigenvector and pagerank) revealed similar responses in both scenarios, which is widely attractive considering the greater financial economy and lower time when applying tests in the field.

Computational and Complex Network Modeling for Analysis of Sprinter Athletes' Performance in Track Field Tests

Sports and exercise today are popular for both amateurs and athletes. However, we continue to seek the best ways to analyze best athlete performances and develop specific tools that may help scientists and people in general to analyze athletic achievement. Standard statistics and cause-and-effect research, when applied in isolation, typically do not answer most scientific questions. The human body is a complex holistic system exchanging data during activities, as has been shown in the emerging field of network physiology. However, the literature lacks studies regarding sports performance, running, exercise, and more specifically, sprinter athletes analyzed mathematically through complex network modeling. Here, we propose complex models to jointly analyze distinct tests and variables from track sprinter athletes in an untargeted manner. Through complex propositions, we have incorporated mathematical and computational modeling to analyze anthropometric, biomechanics, and physiological interactions in running exercise conditions. Exercise testing associated with complex network and mathematical outputs make it possible to identify which responses may be critical during running. The physiological basis, aerobic, and biomechanics variables together may play a crucial role in performance. Coaches, trainers, and runners can focus on improving specific outputs that together help toward individuals' goals. Moreover, our type of analysis can inspire the study and analysis of other complex sport scenarios.

Relationship between anaerobic capacity estimated using a single effort and 30-s tethered running outcomes

The purpose of the current study was to investigate the relationship between alternative anaerobic capacity method (MAOD_ALT) and a 30-s all-out tethered running test. Fourteen male recreational endurance runners underwent a graded exercise test, a supramaximal exhaustive effort and a 30-s all-out test on different days, interspaced by 48h. After verification of data normality (Shapiro-Wilk test), the Pearson’s correlation test was used to verify the association between the anaerobic estimates from the MAOD_ALT and the 30-s all-out tethered running outputs. Absolute MAOD_ALT was correlated with mean power (r = 0.58; P = 0.03), total work (r = 0.57; P = 0.03), and mean force (r = 0.79; P = 0.001). In addition, energy from the glycolytic pathway (E_[La^-_]) was correlated with mean power (r = 0.58; P = 0.03). Significant correlations were also found at each 5s interval between absolute MAOD_ALT and force values (r between 0.75 and 0.84), and between force values and E_[La^-_] (r between 0.73 to 0.80). In conclusion, the associations between absolute MAOD_ALT and the mechanical outputs from the 30-s all-out tethered running test evidenced the importance of the anaerobic capacity for maintaining force during the course of time in short efforts.

Specific Measurement of Tethered Running Kinetics and its Relationship to Repeated Sprint Ability

Repeated sprint ability has been widely studied by researchers, however, analysis of the relationship between most kinetic variables and the effect of fatigue is still an ongoing process. To search for the best biomechanical parameter to evaluate repeated sprint ability, several kinetic variables were measured in a tethered field running test and compared regarding their sensitivity to fatigue and correlation with time trials in a free running condition. Nine male sprint runners (best average times: 100 m = 10.45 ± 0.07 s; 200 m = 21.36 ± 0.17 s; 400 m = 47.35 ± 1.09 s) completed two test sessions on a synthetic track. Each session consisted of six 35 m sprints interspersed by 10 s rest under tethered field running or free running conditions. Force, power, work, an impulse and a rate of force development were all directly measured using the sensors of a new tethered running apparatus, and a one-way ANOVA with Scheffé post-hoc test used to verify differences between sprints (p < 0.05). Pearson product-moment correlation measured the relationship between mechanical variables and free running performance. A total impulse, the rate of force development and maximum force did not show significant differences for most sprints. These three variables presented low to moderate correlations with free running performance (r between 0.01 and −0.35). Maximum and mean power presented the strongest correlations with free running performance (r = −0.71 and −0.76, respectively; p < 0.001), followed by mean force (r = −0.61; p < 0.001) and total work (r = −0.50; p < 0.001). It was concluded that under a severe work-to-rest ratio condition, power variables were better suited to evaluating repeated sprint ability than the other studied variables.

Effects of Sled Towing on Peak Force, the Rate of Force Development and Sprint Performance During the Acceleration Phase

Resisted sprint training is believed to increase strength specific to sprinting. Therefore, the knowledge of force output in these tasks is essential. The aim of this study was to analyze the effect of sled towing (10%, 15% and 20% of body mass (Bm)) on sprint performance and force production during the acceleration phase. Twenty-three young experienced sprinters (17 men and 6 women; men = 17.9 ± 3.3 years, 1.79 ± 0.06 m and 69.4 ± 6.1 kg; women = 17.2 ± 1.7 years, 1.65 ± 0.04 m and 56.6 ± 2.3 kg) performed four 30 m sprints from a crouch start. Sprint times in 20 and 30 m sprint, peak force (Fpeak), a peak rate of force development (RFDpeak) and time to RFD (TRFD) in first step were recorded. Repeated-measures ANOVA showed significant increases (p ≤ 0.001) in sprint times (20 and 30 m sprint) for each resisted condition as compared to the unloaded condition. The RFDpeak increased significantly when a load increased (3129.4 ± 894.6 N·s−1, p ≤ 0.05 and 3892.4 ± 1377.9 N·s−1, p ≤ 0.01). Otherwise, no significant increases were found in Fpeak and TRFD. The RFD determines the force that can be generated in the early phase of muscle contraction, and it has been considered a factor that influences performance of force-velocity tasks. The use of a load up to 20% Bm might provide a training stimulus in young sprinters to improve the RFDpeak during the sprint start, and thus, early acceleration.

Complex network models reveal correlations among network metrics, exercise intensity and role of body changes in the fatigue process

The aims of the present study were analyze the fatigue process at distinct intensity efforts and to investigate its occurrence as interactions at distinct body changes during exercise, using complex network models. For this, participants were submitted to four different running intensities until exhaustion, accomplished in a non-motorized treadmill using a tethered system. The intensities were selected according to critical power model. Mechanical (force, peak power, mean power, velocity and work) and physiological related parameters (heart rate, blood lactate, time until peak blood lactate concentration (lactate time), lean mass, anaerobic and aerobic capacities) and IPAQ score were obtained during exercises and it was used to construction of four complex network models. Such models have both, theoretical and mathematical value, and enables us to perceive new insights that go beyond conventional analysis. From these, we ranked the influences of each node at the fatigue process. Our results shows that nodes, links and network metrics are sensibility according to increase of efforts intensities, been the velocity a key factor to exercise maintenance at models/intensities 1 and 2 (higher time efforts) and force and power at models 3 and 4, highlighting mechanical variables in the exhaustion occurrence and even training prescription applications.