Concomitant application of sprint and high-intensity interval training on maximal oxygen uptake and work output in well-trained cyclists.

PURPOSE: In this study, we compared the effects of two different training modalities on maximal oxygen uptake and work output. METHODS: Participants included 26 well-trained mountain bike cyclists were divided into two groups. The first group trained using a conventional endurance protocol at steady-state (moderate) intensity and variable-intensity (high-moderate-low) free of maximal efforts. The second group combined endurance training with a sprint and high-intensity interval training protocol, which, respectively, were based on 30 s maximal repetitions and 4 min high intensity repetitions. Training duration was 8 weeks. A graded exercise test was administered pre- and post-training. Work output, oxygen uptake, minute pulmonary ventilation, heart rate and stroke volume were determined during the test. RESULTS: While work output significantly increased post-training in both groups (P < 0.05), the interval training group showed a greater magnitude of change (from 284.4 ± 91.9 to 314.2 ± 95.1 kJ) than the endurance training group (from 271.8 ± 73.3 to 283.4 ± 72.3 kJ). Significant increases in maximal oxygen uptake (from 57.9 ± 6.8 to 66.6 ± 5.3 ml kg(-1) min(-1)), maximal pulmonary ventilation and stroke volume were observed only in the interval training group. CONCLUSIONS: An exercise protocol involving endurance and sprint and high-intensity interval training was found to induce positive effects on maximal oxygen uptake in a group of well-trained cyclists with several years athletic experience.

A novel method of anaerobic performance assessment in swimming.

The purpose of this study was to develop a novel, anaerobic efficiency test in swimming. The concept of this test was build upon the classic Wingate anaerobic test, with the difference that the dependent variables are extracted from an instantaneous speed curve. Twelve highly trained male swimmers, 19.3 (±3.3) years of age, 1.84 (±0.08) m in height, and 77 (±12.8) kg in weight, participated in the study. The swimmers swam a 100-m race in a 25-m pool, following the instructions to attain maximal swimming speed as quickly as possible and to keep maximal speed as long as possible. The race was recorded by means of video cameras (50 samples per second). Raw data were filtered by means of standard mathematical functions: smoothing and a polynomial function fit. The following speed parameters: maximal speed (Vmax), time to reach Vmax (tVmax(reach)), time at Vmax (tVmax(keep)), minimal speed (Vmin), and fatigue index were extracted from the filtered speed curve. Thorough assessment of anaerobic performance in swimming requires a swimming test leading to development of a speed curve obtained during a maximal effort race and not race time alone.

Determination of optimal load in the Wingate Anaerobic Test is not depend on number of sprints included in mathematical models.

Determining the optimal load (OPTLOAD) in measuring mechanical peak power output (PPO) is important in assessment of anaerobic fitness. The main goals of this study were: 1) to examine estimated optimal load and PPO based on a force-velocity test and 2) to compare the PPO from the previous method with the Wingate Anaerobic Test (WAnT). The study involved 15 academic male athletes, aged 22.4 ± 2.3 (years), height 178.9 ± 6.8 (cm), and body weight 77.9 ± 12.2 (kg). They performed the 30-s WAnT (7.5% of body weight) during the first visit to the laboratory. Second to fourth session included a force-velocity test (FVT) involving three, 10-s all-out sprints. A randomized load ranging from 3 to 11 kg was used in each session for FVT. The OPTLOAD and PPO were computed using quadratic relationships based on power-velocity (P-v) and power-percent of body weight (P-%BM) and including three, four, five and nine sprints from FVT. The results showed non-difference in OPTLOAD [13.8 ± 3.2 (%BM); 14.1 ± 3.5 (%BM); 13.5 ± 2.8 (%BM); 13.4 ± 2.6 (%BM)] executed at three, four, five, and nine sprints (F3,56 = 0.174, p = 0.91, η2 = 0.01). The two-way ANOVA revealed that PPO were similar between tested models (P-%BM vs. P-v) independently from the numbers of sprints (F3,112 = 0.08, p = 0.99, η2 = 0.000). Moreover, the PPO measured in the WAnT (870.6 ± 179.1 W) was significantly lower compared with in P-v model (1,102.9 ± 242.5-1,134.2 ± 285.4 W) (F4,70 = 3.044, p = 0.02, η2 = 0.148). In addition, the PPO derived from P-%BM model (1,105.2 ± 245.5-1,138.7 ± 285.3 W) was significantly higher compared with the WAnT (F4,70 = 2.976, p = 0.02, η2 = 0.145). The findings suggest the potential utility of FVT for assessment of anaerobic capacity.

Functional model of monofin swimming technique based on the construction of neural networks.

In this study we employed an Artificial Neuronal Network to analyze the forces flexing the monofin in reaction to water resistance. In addition we selected and characterized key kinematic parameters of leg and monofin movements that define how to use a monofin efficiently and economically to achieve maximum swimming speed. By collecting the data recorded by strain gauges placed throughout the monofin, we were able to demonstrate the distribution of forces flexing the monofin in a single movement cycle. Kinematic and dynamic data were synchronized and used as entry variable to build up a Multi-Layer Perception Network. The horizontal velocity of the swimmer's center of body mass was used as an output variable. The network response graphs indicated the criteria for achieving maximum swimming speed. Our results pointed out the need to intensify the angular velocity of thigh extension and dorsal flexion of the feet, to strengthen velocity of attack of the tail and to accelerate the attack of the distal part of the fin. The other two parameters which should be taken into account are dynamics of tail flexion change in downbeat and dynamics of the change in angle of attack in upbeat. Key pointsThe one-dimensional structure of the monofin swimming creates favorable conditions to study the swimming technique.Monofin swimming modeling allows unequivocal interpretation of the propulsion structure. This further permits to define the mechanisms, which determine efficient propulsion.This study is the very first one in which the Neuronal Networks was applied to construct a functional/applicable to practice model of monofin swimming.The objective suggestions lead to formulating the criteria of monofin swimming technique, which plays the crucial role in achieving maximal swimming speed.Theoretical and empirical (realistic) verification created by parameters indicate by neural networks, paves the way for creating suitable models, which could be employed for other sports.

25(OH)D3 Levels Relative to Muscle Strength and Maximum Oxygen Uptake in Athletes.

Vitamin D is mainly known for its effects on the bone and calcium metabolism. The discovery of Vitamin D receptors in many extraskeletal cells suggests that it may also play a significant role in other organs and systems. The aim of our study was to assess the relationship between 25(OH)D3 levels, lower limb isokinetic strength and maximum oxygen uptake in well-trained professional football players. We enrolled 43 Polish premier league soccer players. The mean age was 22.7±5.3 years. Our study showed decreased serum 25(OH)D3 levels in 74.4% of the professional players. The results also demonstrated a lack of statistically significant correlation between 25(OH)D3 levels and lower limb muscle strength with the exception of peak torque of the left knee extensors at an angular velocity of 150°/s (r=0.41). No significant correlations were found between hand grip strength and maximum oxygen uptake. Based on our study we concluded that in well-trained professional soccer players, there was no correlation between serum levels of 25(OH)D3 and muscle strength or maximum oxygen uptake.

Evaluation of Exercise Tolerance in Dialysis Patients Performing Tai Chi Training: Preliminary Study.

UNLABELLED: Introduction. Patients with end-stage renal disease (ESRD) have poor physical performance and exercise capacity due to frequent dialysis treatments. Tai Chi exercises can be very useful in the area of rehabilitation of people with ESRD. OBJECTIVES: The aim of the study was to assess exercise capacity in ESRD patients participating in 6-month Tai Chi training. Patients and Methods. Twenty dialysis patients from Wroclaw took part in the training; at the end of the project, 14 patients remained (age 69.2 ± 8.6 years). A 6-minute walk test (6MWT) and spiroergometry were performed at the beginning and after 6 months of training. RESULTS: After 6 months of Tai Chi, significant improvements were recorded in mean distance in the 6MWT (387.89 versus 436.36 m), rate of perceived exertion (7.4 versus 4.7), and spiroergometry (8.71 versus 10.08 min). Conclusions. In the ESRD patients taking part in Tai Chi training, a definite improvement in exercise tolerance was recorded after the 6-month training. Tai Chi exercises conducted on days without dialysis can be an effective and interesting form of rehabilitation for patients, offering them a chance for a better quality of life and fewer falls and hospitalisations that are the result of it.

Modeling of monofin swimming technique: optimization of feet displacement and fin strain.

The aim of this study was to develop a functional model of monofin swimming by assigning numerical forms to certain technique parameters. The precise determination of optimal foot displacement and monofin strain points toward a model aspect for increasing swimming speed. Eleven professional swimmers were filmed underwater. The kinematic data were then used as entry variable for an artificial neural network, which itself created the foundation for a model of monofin swimming technique. The resulting network response graphs indicate a division set of standard deviation values in which the examined angular parameters of foot and monofin displacement achieve optimal values in terms of gaining maximal swimming speed. During the upward movement, it is essential to limit dorsal foot flexion (-20) from the parallel position toward the shin (180 degrees). During the downward movement, plantar flexion should not exceed 180 degrees. The optimal scope of the proximal part of the fin strain is 35 degrees in the downward move ment and (-)27 degrees in the upward; the angles of attack of the distal part of the fin and its entire surface are limited to 37 degrees in the downward movement and (-)26 degrees in the upward. Optimization criteria allowed for movement modification to gain and maintain maximal velocity during both cycle phases and to limit cycle velocity decrease.