Filipe Antônio de Barros Sousa

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.

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 (MAODALT) 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 MAODALT and the 30-s all-out tethered running outputs. Absolute MAODALT 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 MAODALT 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 MAODALT 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

Abstract 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.

All-out Test in Tethered Canoe System can Determine Anaerobic Parameters of Elite Kayakers.

The aims of this study were to use a specific all-out 30-sec tethered test to determine the anaerobic parameters in elite kayakers and verify the relationship between these results and sports performance. Twelve elite slalom kayakers were evaluated. The tethered canoe system was created and used for the all-out 30-sec test application. Measurements of peak force, mean force, minimum force, fatigue index and impulse were performed. Performance evaluation was determined by measuring the time of race in a simulated race containing 24 gates on a white-water course. Blood was collected (25-µl) for analysis of lactate concentration at rest and at 2, 4, 6, 8 and 10-min intervals after both the all-out test and the simulated race. The Pearson product moment correlation shows a inverse and significant relationship of peak force, mean force and impulse with time of race. Blood lactate concentrations after the all-out test and the simulated race peak at same time (4 min). Additionally, no interaction was visualized between time and all-out test/simulated race for blood lactate concentrations (P <0.365). These results suggest a relationship between the parameters of the all-out test and performance. Thus, the tethered canoe system is a useful tool for determining parameters that could be used in training control of slalom kayakers.

Anaerobic metabolism during short all-out efforts in tethered running: Comparison of energy expenditure and mechanical parameters between different sprint durations for testing

This study’s aims to verify the energy expenditure, metabolic distress and usefulness to evaluate the anaerobic constructs for different all-out durations in running efforts. Twelve active male underwent four testing sessions, one for familiarization and three performing one all-out (AO) tethered running sprint lasting 30s, 20s or 10s. Oxygen consumption, excess post exercise oxygen consumption, and lactate production were retained to analyse metabolic function, together with mechanical power and work as performance parameters. Paired results were compared via one-way ANOVA for repeated measures (Tukey-HSD post-hoc), effect sizes and ICC for absolute agreement. Statistical significance was accepted at p ≤ 0.05. Despite total and energy expenditure from oxidative pathway being significantly higher for longer durations (p < 0.001; ES > 0.7), glycolytic energy expenditure presented an agreement between AO30s and AO20s (ICC-A = 0.63*), while the paired comparisons to AO10s have presented significant differences (p < 0.01; ES > 1.0). Phosphagen energy expenditure were similar between all-out durations (p = 0.12; ICC-A = 0.62*; ES < 0.5). Maximum mechanical power was higher in AO10s than in AO30s (p = 0.03; ES = 0.6), not being different between AO10s and AO20s (p = 0.67; ICC-A = 0.88*; ES = 0.2) and between AO20s and AO30s (p = 0.18; ICC-A = 0.56*; ES = 0.4). In addition, agreement between work in the first ten seconds was confirmed via ICC only between AO10s and AO20s (p = 0.50; ICC-A = 0.86*; ES = 0.3), but not for the other paired comparisons (p < 0.1; ICC < 0.45; ES > 0.5). AO20s is a better alternative to estimate anaerobic power and capacity in one single test, with similar oxidative demand than AO30s.

Aerobic and Anaerobic Swimming Force Evaluation in One Single Test Session for Young Swimmers

This study aims to propose and validate the tethered swimming lactate minimum test (TSLacmin) estimating aerobic and anaerobic capacity in one single test session, using force as measurement parameter. 6 male and 6 female young swimmers (age=15.7±1.1 years; height=173.3±9.5 cm; weight=66.1±9.5 kg) performed 4 sessions comprising i) an all-out 30 s test and incremental test (TSLacmin); ii) 30 min of tethered swimming at constant intensity (2 sessions); iii) free-swimming time trials used to calculate critical velocity. Tethered swimming sessions used an acquisition system enabling maximum (Fmax) and mean (Fmean) force measurement and intensity variation. The tethered all-out test lasting 30 s resulted in hyperlactatemia of 7.9±2.0 mmol·l-1. TSLacmin presented a 100% success applicability rate, which is equivalent to aerobic capacity in 75% of cases. TSLacmin intensity was 37.7±7.3 N, while maximum force in the all-out test was 105±27 N. Aerobic and anaerobic TSLacmin parameters were significantly related to free-swimming performance (r=-0.67 for 100 m and r=-0.80 for 200 m) and critical velocity (r=0.80). TSLacmin estimates aerobic capacity in most cases, and both aerobic and anaerobic force parameters are well related to critical velocity and free swimming performance.

Reliability of the Three-minute All-out Test for Non-motorized Treadmill Tethered Running

The 3-min all-out test was developed and validated on a cycle ergometer using a modification of a linear mathematical equation (1/time vs. power) obtained from the original critical power model. The purpose of this development was to obtain, in a single test, the aerobic and anaerobic capacity parameters and identify the exercise transition moment from heavy to severe intensity. The aim of this study was to propose an adaptation of the all-out 3-min cycle ergometer to a non-motorized treadmill with tethered running. In addition, we tested the reproducibility of this adapted protocol, highlighting the need for mechanical power evaluation using a specific ergometer. Consequently, 10 physically active individuals visited the laboratory 4 times for testing and data collection. The results suggested that the protocol adaptation for the 3-min all-out test for non-motorized treadmill with tethered running was reproducible and feasible. It was also possible to show that the AO3 application in this ergometer ensures the specificity of the sports that involve the running exercise, from assessment of both aerobic and anaerobic parameters, accomplished in a single day of application.

Novel paddle stroke analysis for elite slalom kayakers: Relationship with force parameters

This study was divided into two complementary parts. In Part 1, we proposed a novel paddle strokes analysis based on the force signal from a 30-s all-out tethered test; and compared these results with video recordings. In Part 2, we investigated the relationship between force data from the same test with paddle stroke results from both methods. Eleven male elite slalom kayakers (Brazilian national team) were evaluated. The tethered test was conducted for force parameters analysis (peak-force, mean-force, impulse). Video recording analysis was conducted, and the performed strokes (V.NumberPaddle) was counted and frequency (V.FrequencyPaddle) calculated by the V.NumberPaddle divided by 30 (i.e. total time of test). The new method consisted of performed strokes and frequency achievement from a load cell force signal analysis (S.NumberPaddle and S.FrequencyPaddle, respectively). Paired test-t did not show difference between methods results, but significant correlations were only obtained for the number of paddle strokes. Force parameters were only correlated with S.NumberPaddle and S.FrequencyPaddle. Overall, considering the theoretical and practical application, we propose that the new method should be used as an alternative to the video recording.

The 3-min all-out test is valid for determining critical power but not anaerobic work capacity in tethered running

The purpose of the study was to investigate if the 3-min all-out test (3MT) is valid for obtaining critical power intensity (CP) and the amount of work that can be performed above CP (W’) on non-motorized treadmills in tethered running. Eight physically active individuals (24 ± 3 years; 78.3 ± 8.7 kg; 179 ± 5 cm; 9.0 ± 2.5% body fat) performed four different efforts at constant intensity to exhaustion in order to determine CP and W’. The mechanical power values obtained were subsequently plotted with their corresponding time to exhaustion (limit time) for application of three mathematical models: power hyperbolic versus time limit (Hyp), linear power versus 1/time (P vs 1/t) and linear work versus time limit (Ԏ vs t). The 3MT test was carried out on the last day to determine end power (EP) and anaerobic capacity (WEP) using this methodology. EP value of 181.7 ± 52 was similar (p = 0.486) to 178.2 ± 61 (CP Hyp), 191.4 ± 55 (Ԏ vs t) and 188.3 ± 55 (P vs 1/t). WEP value of 17.9 ± 4.8 was not similar (p = 0.000) to 50.2 ± 15.3 (CP Hyp), 44.8 ± 8.7 (Ԏ vs t) and 45.5 ± 8.4 (P vs 1/t). Positive results (r = 0.78–0.98 and ICC = 0.88–0.99) of Pearson correlation and intraclass correlation (ICC–absolute agreement) were found for aerobic applications of conventional CP and 3MT. For anaerobic data, only the three models of conventional CP were correlated (r = 0.76–0.93); however, W’ from the three models was not correlated with WEP (r = 0.37–0.52). The results of this study suggest that 3MT in tethered running on non-motorized treadmills is a valid test for estimating CP aerobic parameters in a single day of application but not anaerobic parameters of W’.

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.