Rodrigo Gomes da Rosa

Incline and level running on treadmills have been extensively studied due to their different cardiorespiratory and biomechanical acute responses. However, there are no studies examining the performance determinants of outdoor running on hilly terrains. We aimed to investigate the influence of anthropometrics, muscle strength, and cardiorespiratory and gait spatiotemporal parameters during level (0%) and inclined (+7%) running on performance in level and hilly 5-km races. Twenty male recreational runners completed two 5-km outdoor running tests (0% vs. +7% and −7%), and two submaximal (10 km·h⁻¹) and incremental treadmill tests at 0 and 7% slopes, after complete laboratory evaluations. The velocity at maximal oxygen consumption (VO₂max) evaluated at 7% incline and level treadmill running were the best performance predictors under both hilly (R² = 0.72; p < 0.05) and level (R² = 0.85; p < 0.01) conditions, respectively. Inclusion of ventilatory and submaximal heart rate data improved the predictive models up to 100%. Conversely, none of the parameters evaluated in one condition contributed to the other condition. The spatiotemporal parameters and the runners’ strength levels were not associated to outdoor performances. These results indicate that the vVO₂max evaluated at similar slopes in the lab can be used to predict 5-km running performances on both level and hilly terrains.

The main objective of this study is to propose a form of walking/running protocol that is capable of evaluating energy expenditure at different types of slopes, considering the same relative intensities (iso-intensity conditions), as well as to assess biomechanical and hemodynamic factors that may be associated. 11 obese adult men (BMI between 30 kg.m-2 and 39.9 kg.m-2) aged between 18 and 35 years, physically inactive. Assessments will be carried out on six different days. On the first day, body composition, familiarization with the equipment, and a maximum incremental test without slope. In the next two days, the maximums tests in positive and negative slope will be performed. In the other three days, biomechanical, energetics, and cardiac variables will be collected in the following conditions: fixed speed (4.5 km.h-1), speed relative to the first, and the second ventilatory threshold, being one day for tests on the positive slope, one on the negative slope and one without slope. From the second day, the tests will be distributed in random order and with an interval of, at least, 72 hours between tests. Metabolic data will be obtained using a gas analyzer, biomechanical data will be obtained through a kinematics system, with six infrared cameras, data Ground Reaction Forces (GRF) are obtained through force sensors installed on the treadmill, and hemodynamic parameters using a Signal-Morphology impedance device. The primary outcome is energy expenditure concerning slopes and speeds and the secondary outcomes are the mechanical work, mean GRF, and hemodynamic aspects. The data will be described by the mean and standard error values. The interactions between slopes and speeds will be tested with Generalized Estimating Equations (GEE) and Bonferroni post-hoc, adopting a significance level (α) of 0.05. Also, effect sizes (ES) will be calculated. The energy expenditure should be greater on the positive slope at all speeds. Higher production of positive mechanical work is expected on the positive slope and the impact peaks should be less in this condition. The negative slope should enable higher speeds relative to the thresholds, as well as lower cardiovascular load.

The objective of this study was to evaluate effects of photobiomodulation therapy (PBMT) on the 3000 m running performance (primary outcome), running economy (RE), metabolic cost and ratings of perceived exertion during running (secondary outcomes). Twenty male endurance athletes performed 4-min treadmill rectangular test at 12 km.h-1 monitored by a gas analyser. After that, PBMT or placebo in each lower limb was applied, followed performed a maximum test of 3000 m. Immediately after 3000 m test, the athletes repeated the treadmill test. Another application of PBMT/placebo was done after the treadmill test, and athletes went back to the laboratory 24 h later to repeat the treadmill test. After a 72 h interval, athletes repeated all procedures with another treatment intervention (PBMT/placebo). Athletes performed the 3000 m running test ~7s faster when treated with PBMT with similar effort score compared placebo condition. The RE remains unchanged immediately post 3000 m running test, nonetheless RE measured post-24 h improved by 5% with PBMT application without changes in metabolic cost. The PBMT pre- and post-conditioning enhanced the 3000 m running performance and improved RE 24 h following the 3000 m test. However, no changes on ratings of perceived exertion and metabolic cost with the application of PBMT.

New Findings: What is the central question of this study? The aim was to compare the cost of transport and mechanical work between obese and non‐obese children at different walking speeds. What is the main finding and its importance? Our data show that the cost of transport, mechanical efficiency and work are similar and directly mass dependent in obese and non‐obese children. The optimal walking speed (most economical walking speed) is reduced in obese children. Although studies have shown the influence of gait biomechanics on the metabolic economy in obese adults and adolescents, little is known regarding obese children. We compared the metabolic cost of transport, apparent mechanical efficiency and gait biomechanics (assessed by mechanical energy fluctuations) in obese children (n = 12; mean ± SD: 8.6 ± 0.51 years of age, 1.38 ± 0.04 m, 44.6 ± 6.65 kg, 24.1 ± 3.50 kg m⁻²) and age‐ and sex‐matched non‐obese children (n = 12, 7.8 ± 0.90 years of age, 1.31 ± 0.08 m, 26.8 ± 2.24 kg, 16.4 ± 1.40 kg m⁻²) while walking at different speeds (from 1 to 5 km h⁻¹) on a treadmill. We found that the mechanical efficiency was higher at 3 km h⁻¹ compared with the remaining speeds for both groups (P < 0.05). Although the internal mechanical work has been greater in obese compared with non‐obese children at 4 and 5 km h⁻¹, the external, total mechanical work and the mechanical efficiency remained similar between obese and non‐obese children at all speeds. Likewise, the cost of transport was similar in the two groups, although the optimal walking speed was an average of 0.4 km h⁻¹ slower in obese children. Clearly, these results show that the walking economy is associated with the total mechanical work in obese and non‐obese children. Finally, the reduced functional mobility in obese children observed in previous studies seems to be associated with a reduction in optimal walking speed in comparison to non‐obese children.

Endurance running has become an immensely popular sporting activity, with millions of recreational runners around the world. Despite the great popularity of endurance running as a recreational activity during leisure time, there is no consensus on the best practice for recreational runners to effectively train to reach their individual objectives and improve physical performance in a healthy manner. Moreover, there are lots of anecdotal data without scientific support, while most scientific evidence on endurance running was developed from studies observing both recreational and professional athletes of different levels. Further, the transference of all this information to only recreational runners is difficult due to differences in the genetic predisposition for endurance running, the time available for training, and physical, psychological, and physiological characteristics. Therefore, the aim of this review is to present a selection of scientific evidence regarding endurance running to provide training guidelines to be used by recreational runners and their coaches. The review will focus on some key aspects of the training process, such as periodization, training methods and monitoring, performance prediction, running technique, and prevention and management of injuries associated with endurance running.

Background: Elastic bouncing is a physio-mechanical model that can elucidate running behavior in different situations, including landing and takeoff patterns and the characteristics of the muscle-tendon units during stretch and recoil in running. An increase in running speed improves the body’s elastic mechanisms. Although some measures of elastic bouncing are usually carried out, a general description of the elastic mechanism has not been explored in running performance. This study aimed to compare elastic bouncing parameters between the higher- and lower-performing athletes in a 3000 m test. Methods: Thirty-eight endurance runners (men) were divided into two groups based on 3000 m performance: the high-performance group (P_high; n = 19; age: 29 ± 5 years; mass: 72.9 ± 10 kg; stature: 177 ± 8 cm; 3000_time: 656 ± 32 s) and the low-performance group (P_low; n = 19; age: 32 ± 6 years; mass: 73.9 ± 7 kg; stature: 175 ± 5 cm; 3000_time: 751 ± 29 s). They performed three tests on different days: (i) 3000 m on a track; (ii) incremental running test; and (iii) a running biomechanical test on a treadmill at 13 different speeds from 8 to 20 km h⁻¹. Performance was evaluated using the race time of the 3000 m test. The biomechanics variables included effective contact time (t_ce), aerial time (t_ae), positive work time (t_push), negative work time (t_break), step frequency (f_step), and elastic system frequency (f_sist), vertical displacement (S_v) in t_ce and t_ae (S_ce and S_ae), vertical force, and vertical stiffness were evaluated in a biomechanical submaximal test on treadmill. Results: The t_ae, f_sist, vertical force and stiffness were higher (p < 0.05) and t_ce and f_step were lower (p < 0.05) in P_high, with no differences between groups in t_push and t_break. Conclusion: The elastic bouncing was optimized in runners of the best performance level, demonstrating a better use of elastic components.

Knee peak torque (PT) is associated to jump performance in volleyball players. It is not clear whether muscle strength imbalances of the knee joint can influence jump performance. The purpose of study was to analyse the association between PT and knee muscular imbalances with jump performance in professional volleyball players. Eleven elite male volleyball players (90.3 ± 9.7 kg body mass and 1.94 ± 0.06 m height) were evaluated in an isokinetic dynamometer at speeds of 60, 180 and 300 deg/s. Muscle strength imbalances were obtained through calculation of contralateral deficit between limbs and the conventional ratio (hamstrings/quadriceps). Countermovement jump (CMJ) was performed on a force plate to calculate mechanical power and height. Association was found between knee extensor PT at 180 deg/s with CMJ power (r = 0.610, p = 0.046). Conventional ratio at 300 deg/s showed negative association with CMJ (r = −0.656, p = 0.029). The optimal ratio between knee extensors PT in relation to the flexors PT is associated with the greater mechanical power in CMJ. Contralateral deficit does not seem to be associated with the CMJ performance. Considering the knee extensor PT is associated with CMJ power, our findings suggest that strength-based training in volleyball athletes should not omit the conventional muscle ratio.

Aerobic training has a neuroprotective effect in people with Parkinson’s disease. Recent evidence indicates that Nordic walking seems a promising alternative due to positive outcomes in functional mobility. However, the effects of Nordic walking compared to free walking on static and functional balance parameters are still unknown. The aim of this study was to evaluate the effects of nine weeks of Nordic and free walking training on static and functional balance. The sample size was 33 individuals with eight dropouts, leaving 25 individuals in the final sample (Nordic Walking, n=14, Free Walking, n=11). The participants underwent two evaluations in the present randomized clinical trial, pre- and post-training, to determine average velocity and root-mean-square values from center of pressure with eyes open and eyes closed. The functional balance showed approximately 5% improvement for the two groups (p=0.04). The results indicate that nine weeks of Nordic and free walking training were enough to induce improvements in the proprioceptive system and functional balance.

Although studied at level surface, the trunk kinematics and pelvis-shoulder coordination of incline walking are unknown. The aim of this study was to evaluate the speed effects on pelvis-shoulder coordination and trunk movement and the cost of transport (C) during unloaded and loaded (25% of body mass) 15% incline walking. We collected 3-dimensional kinematic and oxygen consumption data from 10 physically active young men. The movements were analyzed in the sagittal plane (inclination and range of trunk motion) and the transverse plane (range of shoulder and pelvic girdle motion and phase difference). The rotational amplitude of the shoulder girdle decreased with load at all speeds, and it was lower at the highest speeds. The rotational amplitude of the pelvic girdle did not change with the different speeds. The phase difference was greater at optimal speed (3 km.hr⁻¹, at the lowest C) in the loaded and the unloaded conditions. The trunk inclination was greater with load and increased with speed, whereas the range of trunk motion was lower in the loaded condition and decreased with increasing speed. In conclusion, the load decreased the range of girdles and trunk motion, and the pelvis-shoulder coordination seemed to be critical for the incline walking performance.