Reliability of Peak Running Velocity Obtained on the Track Field in Runners of Different Performance Levels

The aim of this study was to verify the reliability of peak running velocity obtained on the track field (V_{peak_TF}) in runners of different performance levels. 39 male endurance runners were divided into two groups: trained runners (TR; n = 22; 10-km time running performance of 35.2 ± 1.7 min), and recreational runners (RR; n = 17; 10-km time running performance of 51.3 ± 4.8 min). They performed three maximal incremental running tests on the official track field (400 m), with an interval of 1 week between trials to determine the reliability of V_{peak_T}. The V_{peak_TF} showed high reliability, presenting an intraclass correlation coefficient and coefficient of variation of 0.97 and 1.28%, and 0.90 and 1.24% for TR and RR, respectively. Both TR and RR showed lowest bias and limits of agreement between test and retest (V_{peak_TF1} and V_{peak_TF2}). In addition, there was no statistical test-retest difference for V_{peak_TF}. In addition, the HR and RPE submaximal values were reliable for both TR and RR. Therefore, the V_{peak_TF} showed high reliability in both TR and RR. These findings reinforce that the protocol for determining V_{peak_TF}, using increments of 1 km h^–1 every 3 min is reliable regardless of the performance level of the runners.

Peak Running Velocity or Critical Speed Under Field Conditions: Which Best Predicts 5-km Running Performance in Recreational Runners?

This study aimed to examine which variable, between the peak running velocity determined on the track field (V_{peak_TF}) and critical speed (CS), is the best predictor of the 5-km running performance in recreational runners. Twenty-five males performed three tests to determine the V_{peak_TF}, CS, and 5-km running performance on the track field, with a minimal interval of 48 h between each test. The V_{peak_TF} protocol started with a velocity of 8 km⋅h^–1, followed by an increase of 1 km⋅h^–1 every 3 min until volitional exhaustion, which was controlled by sound signals, with cones at every 25 m indicating when the participants were required to pass the cone’s position to maintain the required velocity. The participants performed three time trials (TTs) (1: 2,600 m; 2: 1,800 m; and 3: 1,000 m) on the same day, with a 30-min rest period to determine the CS through the combinations of three (CS₁,₂,₃) and two TTs (CS₁,₂, CS₁,₃, and CS₂,₃). The 5-km running performance time was recorded to determine the test duration, and the mean velocity (MV) was calculated. There was a significant difference observed between the V_{peak_TF} and the MV 5-km running performance. However, no differences were found between the CS values and the MV 5-km running performance. A correlation was observed between the V_{peak_TF} (R = −0.90), CS₁,₂,₃ (R = −0.95), CS₁,₃ (R = −0.95), and the 5-km running performance time. Linear regression indicated that the V_{peak_TF} (R² = 0.82), CS₁,₂,₃ (R² = 0.90), and CS₁,₃ (R² = 0.90) significantly predicted the 5-km running performance time. The CS results showed a higher predictive power for the 5-km running performance, slightly better than the V_{peak_TF}. Also, CS₁,₂,₃ and the CS₁,₃ presented the highest predictive power for the 5-km running performance of recreational runners.

Effect of beetroot juice supplementation on 10-km performance in recreational runners

The purpose of this study was to investigate the effects of chronic beetroot juice (BRJ) supplementation on 10-km running performance in recreational runners. In a double-blind, placebo-controlled, crossover-designed study, 14 male recreational runners (age, 27.8 ± 3.4 years) performed three 10-km running tests, at baseline and under the conditions of BRJ supplementation and placebo (PLA). Supplementation was administered for 3 days, and on the days of the assessments, the ingestion occurred 2 h before the test and consisted of a dose of 420 mL of BRJ in natura (8.4 mmol inorganic nitrate (NO3−)·day−1) or PLA with depleted NO3− (0.01 mmol NO3−·day−1). The mean velocity (MV) was calculated, and the following variables were determined: maximal heart rate, maximal rating of perceived exertion, blood glucose concentration (analyzed before and after the test), and lactate peak. There was no main effect between conditions regarding 10-km running time performance (BRJ: 50.1 ± 5.3 min; PLA: 51.0 ± 5.1 min; P = 0.391) and total MV (BRJ: 12.1 ± 1.3 km·h−1; PLA: 11.9 ± 1.2 km·h−1; P = 0.321) or in the other analyzed variables. The time to complete the first half of the test (5 km) was statistically lower in the BRJ group than in the PLA group (P = 0.027). In conclusion, chronic supplementation with BRJ increased MV in the first half of the test and improved the final test times of 10 of the 14 runners, although we did not find a statistically significant difference in the performance of the 10-km run.

PONTOS DE TRANSIÇÃO DA FREQUÊNCIA CARDÍACA NA MARCHA ATLÉTICA

RESUMO Introdução: A frequência cardíaca fornece informações úteis para os treinamentos de marcha atlética. Objetivo: O objetivo do estudo foi analisar o comportamento da frequência cardíaca (FC) e seus pontos de inflexão (PIFC) e deflexão (PDFC) em teste progressivo de marcha atlética (TPMA) antes e depois de 20 sessões de treinamento. Métodos: Participaram 13 jovens atletas (12,46 ± 1,61 anos, 44,29 ± 10,25 kg, 157,93 ± 12,03 cm, 24,39 ± 7,60 %G). O TPMA foi realizado em uma pista oficial de atletismo, antes e depois do treinamento. Os dados de FC e carga foram plotados a cada minuto para identificação dos PIFC e PDFC. Resultados: A FC apresentou comportamento sigmoide, com identificação dos pontos de transição (PT), sendo no pré-treinamento: a) oito sujeitos PIFC (5,31 km·h-1; 125 bpm) e PDFC (7,63 km·h-1; 169 bpm); b) um sujeito somente PIFC (7,00 km·h-1; 149 bpm); c) um sujeito somente PDFC (8,00 km·h-1; 170 bpm); d) três sujeitos sem detecção de PT e no pós-treinamento: a) em 12 sujeitos PIFC (5,46 km·h-1; 125 bpm) e PDFC (7,75 km·h-1; 168 bpm); b) um sujeito somente PDFC (7,50 km·h-1; 184 bpm). O PIFC foi encontrado em carga significativamente inferior ao PDFC no pré (p < 0,001) e no pós-treinamento (p < 0,001). Quando comparamos o PIFC e o PDFC pré e pós, não encontramos diferença significativa, seja em relação à carga (p = 0,87 e p = 0,61) ou FC (p = 0,60 e p = 0,99). Conclusão: Conclui-se que a FC tem relação curvilínea com a carga, sendo possível detectar os seus pontos de transição em TPMA.

Peak velocity and its time limit are as good as the velocity associated with VO 2max for training prescription in runners

This study compared the effects of 4 weeks of training prescribed by peak velocity (V _peak ) or velocity associated with maximum oxygen uptake (vVO _2max ) in moderately trained endurance runners. Study participants were 14 runners (18–35 years) randomized into 2 groups, named group VO ₂ (GVO ₂ ) and group V _peak (GVP). The GVO ₂ had training prescribed by vVO _2max and its time limit (t _lim ), whereas the GVP had training prescribed by V _peak and its t _lim . Four tests were performed on a treadmill: 2 maximum incremental for V _peak and vVO _2max and 2 for their t _lim . Performance (10 km) was evaluated on a 400 m track. Evaluations were repeated after 4 weeks of endurance training. The results showed a significant effect of training on V _peak [GVP (16.7±1.2 – 17.6±1.5 km ^. h ⁻¹ ), GVO ₂ (17.1±1.9–17.7±1.6 km·h ⁻¹ )]; vVO _2max [GVP (16.4±1.4–17.0±1.3 km·h ⁻¹ ), GVO ₂ (17.2±1.7–17.5±1.9 km·h ⁻¹ )]; and 10 km performance [GVP (41.3±2.4–39.9±2.7 min), GVO ₂ (40.1±3.4–39.2±2.9 min)]. The V _peak highly correlated with performance in both pre- and post-training in GVP (–0.97;–0.86) and GVO ₂ (–0.95;–0.94), as well as with vVO _2max in GVP (–0.82;–0.88) and GVO ₂ (–0.99; –0.98). It is concluded that training prescribed by V _peak promoted similar improvements compared to training prescribed by vVO _2max . The use of V _peak is recommended due to its practical application and the low cost of determination.