Reliability and validity of three portable devices for quantifying spatiotemporal parameters in runners of different athletic abilities during treadmill running.

This study aimed to evaluate the validity and reliability of a wearable device and a phone application for measuring spatiotemporal parameters and their relationship with running economy (RE) by comparing them with photocell data in runners of different abilities. Twenty-three male runners were divided into well-trained and recreational groups and performed a 4-min running bout at 17 and 13 km·h-1 respectively. During the bout, were measured the spatiotemporal parameters with three devices (Stryd, Runmatic, and Optojump) and RE with a gas analyser. Pearson correlation showed perfect relationships for stride frequency (SF) and stride length (SL) between the devices, and moderate for flight time (FT) and contact time (CT). There were no correlations between the spatiotemporal parameters and RE measurements. Coefficient of variation was ~ 5% in all devices for CT, SF, and SL, and higher for FT (15-24%). CT was underestimated (15-16% with Runmatic and Stryd, respectively) and FT was overestimated (36-40%) compared to Optojump. Bland-Altman plots revealed that Runmatic could be a more accurate system than Stryd. In conclusion, both devices were valid tools for measuring spatiotemporal parameters during running at RE speed. Runmatic was more valid and reliable in comparison with Stryd. In addition, at lower running speeds the devices showed less reliability.

Modelling performance by continents in swimming.

Introduction: There is a growing interest in the scientific community about the progression and congruity in the performance of talented participants who complete representing different nations in the most important international events. The prediction of incoming performances is nowadays in demand with the objective of returning in talent investment. Talent identification programs have tried to select and develop sports talent over years. However, to our knowledge, there is a lack of research about success in swimming World Championships (WCs) performance considering continents-country and how successful outcomes are influenced by these variables. Therefore, the primary goal is to analyze the effect of early specialization comparing the performance progression model of the countries gathered by continents. Methods: Participant's data from all Junior and Senior WCs between 2006 and 2017 from International Swimming Federation (FINA). One-way ANOVA, ANCOVA and regression model were used to explain whether the variable category, age, best z-score, experience, and continent influences the performance obtained in Absolute WC. Results: Significant differences (p < 0.01) were found between the average performance obtained by the two different categories (junior: swimmers participating in junior WCs before senior WCs; senior: swimmers participating in senior WCs without previous participation in junior WCs), where swimmers from category junior showed significant better performance's times than seniors, except in America. ANCOVA results showed that generally, the greatest differences where in the earliest ages, with best performance registered in category junior in all the continents. Also, the experience was a significant variable in the general model. Conclusion: Swimmers who had participated in junior category prior absolute obtained better performance's times than those swimmers who participated directly in absolute, in the first participation in senior WC. Thus, early specialization is a key factor to obtain better results in senior WCs for all the continents, except in America.

Periodization of altitude training: A collective case study of high-level swimmers.

The objective was to quantify parallel changes in performance and physiological measures in relation to periodization of sequential altitude training over a season in elite swimmers. The altitude training of four female and two male international swimmers in selected seasons was examined using a collective case study approach. All swimmers were a medalist in World (WC) and/or European Championships (EC) 2013, 2014, 2016 and 2018 in short or long course competition. A traditional periodization model was employed using three macrocycles with 3-4 altitude camps (duration 21-24 days each) scheduled over the season, following a polarized training intensity distribution (TID) with a volume ranged between 729 km and 862 km. The timing of return from altitude prior to competition was between 20-32 days, with 28 days the most common period. Competition performance was assessed with major (international) and minor (regional or national) competitions. Hemoglobin concentration, hematocrit, anthropometric characteristics, were measured before and after each camp. Competition performance following the altitude training camps improved by 0.6% ± 0.8% (personal best time; mean ± SD) (95% confidence limits (CL) 0.1%-1.1%), 1.6% ± 0.7% (95% CL 1.2% to 2.0%) (season best time) and 1.6% ± 0.5% (95% CL 1.3%-1.9%) (previous season time). Hemoglobin concentration increased 4.9% from pre-to post-altitude training camps, while hematocrit increased by 4.5%. The sum of six skinfolds reduced by 14.4% (95% CL 18.8%-9.9%) and 4.2% (95% CL 2.4%-9.2%) for the two males (EC), and by 15.8% (95% CL 19.5%-12.0%) for two females (WC). Three to four altitude training camps in a competitive season, around 21-24 days of duration, scheduling the last return between 20-32 days before the main competition, integrated in a traditional periodized sequence, can induce worthwhile improvements in international swimming performance, hematological parameters, and anthropometric characteristics.

Medium term effects of physical conditioning on breath-hold diving performance.

The current study aimed to analyze the effects of physical conditioning inclusion on apnea performance after a 22-week structured apnea training program. Twenty-nine male breath-hold divers participated and were allocated into: (1) cross-training in apnea and physical activity (CT; n = 10); (2) apnea training only (AT; n = 10); and control group (CG; n = 9). Measures were static apnea (STA), dynamic with fins (DYN) and dynamic no fins (DNF) performance, body composition, hemoglobin, vital capacity (VC), maximal aerobic capacity (VO2max), resting metabolic rate, oxygen saturation, and pulse during a static apnea in dry conditions at baseline and after the intervention. Total performance, referred as POINTS (constructed from the variables STA, DNF and DYN) was used as a global performance variable on apnea indoor diving. + 30, +26 vs. + 4 average POINTS of difference after-before training for CT, AT and CG respectively were found. After a discriminant analysis, CT appears to be the most appropriate for DNF performance. The post-hoc analysis determined that the CT was the only group in which the difference of means was significant before and after training for the VC (p < 0.01) and VO2max (p < 0.05) variables. Inclusion of physical activity in apnea training increased VC and VO2max in breath hold divers; divers who followed a mixed training, physical training and hypoxic training, achieved increased DNF performance.

Swimming championship finalist positions on success in international swimming competitions.

The primary goal was to determine whether the achievement of finalist positions in the Junior Championship was associated with the achievement of success in the International Swimming Federation (FINA) World Championship (WC). Secondary goals included analyzing the effect of various factors (gender, age, country, etc) on swimmers' performances. Data were obtained from FINA information about the finalists from 2007 to 2015 WCs and finalists from 2006 to 2013 Junior-WCs (2400 entries). Final filtered database just included swimmers who participated in both junior and senior WCs (719 entries). A univariate general linear model (GLM) was used to examine the association between time; origin (swimmer who participated in Junior WC or not); maintenance years (number of years achieving finalist positions); country; and age, adjusting for year of competition. An ordinal logistic regression (OLR) model was used to identify predictors of achieving the top positions. The origin variable was not significant in either the GLM or the OLR. The only significant variables in the GLM were maintenance years (F4,706 = 7.689; p < .05) and year of competition (F4,706 = 23.239; p < .05). The OLR revealed a strong association (p < .001) between the position variable and maintenance years, getting better positions as you get more WCs (odds = 1.85). In conclusion, no evidence was obtained to conclude finalist position in Junior WC have influence in achieve success in FINA WC. Maintenance years in WCs have a positive impact to achieve better positions.

Autonomic adaptation after traditional and reverse swimming training periodizations.

The objective of the present study was to analyze the autonomic response of trained swimmers to traditional and reverse training periodization models. Seventeen swimmers were divided in two groups, performing a traditional periodization (TPG) or a reverse periodization (RPG) during a period of 10 weeks. Heart rate variability and 50 m swimming performance were analyzed before and after the training programs. After training, the TPG decreased the values of the high frequency band (HF), the number of differences between adjacent normal R-R intervals longer than 50 ms (NN50) and the percentage of differences between adjacent normal R-R intervals more than 50 ms (pNN50), and the RPG increased the values of HF and square root of the mean of the sum of the squared differences between adjacent normal R-R intervals (RMSSD). None of the groups improved significantly their performance in the 50-m test. The autonomic response of swimmers was different depending on the periodization performed, with the reverse periodization model leading to higher autonomic adaption. Complementary, the data suggests that autonomic adaptations were not critical for the 50-m swimming performance.

Short-term periodized aerobic training does not attenuate strength capacity or jump performance in recreational endurance athletes.

The purpose of this study was to investigate the effects of three different distributions of aerobic training on the isokinetic strength and vertical jump performance [SJ, CMJ and Abalakov (ABA)] in thirty middle-aged endurance athletes (38.7 ± 9.8 yrs; 174.7 ± 6.5 cm; 72.0 ± 9.8 kg). Three zones of training were required to quantify volume of training: Zone 1, low-intensity-training < VT1; Zone 2, threshold-training, between VT1 and VT2; and Zone 3, high-intensity-training > VT2. The INC group (n = 10) began training in the Zone 1 and then gradually built up training in Zone 2 and Zone 3, thereby increasing the intensity of aerobic activity over the 4-week training period. The CON group (n = 10) performed the same activity every week in Zones 1, 2 and 3. The FRE group followed a free distribution of endurance training loads (n = 10). The results showed significant decreases in peak torque knee extension 30° (p < 0.05) in CON group and significant decreases (p < 0.05) in ABA in FRE group. Results provide a physiological basis to support several performance studies that consistently indicate 5 d·wk(-1) endurance training does not impair strength development over the short term. In conclusion, variations in volume and intensity in training groups did not interfere with isokinetic strength and vertical jump performance.

The traditional maximal lactate steady state test versus the 5 × 2000 m test.

Here, we compared the maximal lactate steady state velocity (vMLSS) estimated from a single-visit protocol (v5×2000) to the traditional multi-day protocol (vMLSS). Furthermore, we determined whether there was a lactate steady state during the time limits (Tlim) at vMLSS or v5×2000. Eight runners completed a half marathon (HM), the traditional protocol to determine the vMLSS and the 5×2000 m test in a randomised order, and a Tlim at vMLSS and at v5×2000 in a randomised order. The vMLSS (13.56±0.90 km·h - 1) was higher than the v5×2000 (12.93±0.90 km·h - 1, p=0.001) and comparable to the vHM (13.34±0.75 km·h - 1). The vMLSS (r=0.83) and the v5×2000 (r=0.91) were associated with the vHM but were not indicative of the competition pace. The Tlim at vMLSS (64±15 min) was lower than the Tlim at v5×2000 (94±21 min) and the HM time (95±5 min). In both Tlim, lactate was lower at 45 min than upon finishing the effort and was predictive of its duration (p<0.05). Our results indicate that the 5×2000 m test can be equally useful to assess runners as the traditional MLSS protocol and that there is no lactate steady state during the Tlim at vMLSS or at v5×2000.