Heart rate cost of running in track estimates velocity associated with maximal oxygen uptake.

BACKGROUND: Running velocity associated with VO2max (vVO2max) is a parameter widely used for exercise prescription and is related to endurance performance. However, the vVO2max determination usually requires a maximal effort test and equipped laboratory for expired gas analysis, what make difficulty its assessment. OBJECTIVE: We aimed to test the validity of a simple method of vVO2max prediction through the heart rate cost of running (HRC) in a submaximal 6-min running test, both in treadmill and in a 400-meter track. METHODS: Male recreational runners (n = 16; 30.3 ±â€¯8.0 years; VO2max of 46.2 ±â€¯3.2 ml·kg-1·min-1) randomly underwent an incremental test in treadmill with gas analysis, and a 3000-m time trial in a track, to determine vVO2max. Before every maximal test, participants also performed a submaximal 6-min running (~85% HRmax), both in the treadmill and in a track, to assess HRC (bpm-1m·min-1) by dividing the submaximal running velocity by its respective HR. The vVO2max (km·h-1) was predicted by dividing the HRmax (bpm)/HRC (bpm-1m·min-1). RESULTS: No differences were verified (p > .05) among vVO2max determined both in the treadmill (13.8 ±â€¯0.9 km·h-1) and track (13.6 ±â€¯0.9 km·h-1) to those predicted by the HRC method both in treadmill (13.5 ±â€¯0.8 km·h-1) and track (13.6 ±â€¯1.0 km·h-1). The vVO2max measured directly with expired gas analysis was highly correlated with vVO2max estimated through HRC in treadmill and track (p < .05). Additionally, the intraclass correlation coefficient (ICC) and Bland-Altman technique revealed good agreement and reliability classified with substantial agreement [ICC = 0.673 (95% CI 0.064-0.886; p = .019)] and almost perfect agreement [ICC = 0.870 (95% CI 0.628-0.955 p = .0001)] between methods to identify vVO2max, respectively. CONCLUSION: A submaximal 6-min exercise test protocol to assess HRC of running was considered valid to estimate vVO2max of recreational runners both in treadmill and outdoor track.

Efeito da ordem do exercício concorrente na percepção de esforço em jovens atletas de jiu-jitsu / Alternations at the perceptual to different combined exercise in young athletes of jiu-jitsu

O objetivo do presente estudo foi verificar a resposta da percepção subjetiva de esforço (PSE) de jovens atletas de jiu-jitsu frente a diferentes ordens de aplicação do exercício aeróbio, resistido e concorrente (EC). Para isso a amostra foi composta por dez praticantes de jiu-jitsu, sexo masculino, aparentemente saudáveis (22.6 ± 3.7 anos; 70.3 ± 5.8kg; 175.9 ± 5.8 cm), após serem avaliados para aptidão aeróbia (limiar anaeróbio-LA) e força (12 repetições máximas–RM´s), participaram em dias distintos de 4 sessões experimentais, sendo: 1) Aeróbio+resistido (AR); 2) Resistido+aeróbio (RA); 3) Circuito concorrente exercício aeróbio/exercício resistido alternados (CC); 4) Controle (CO). As sessões tiveram a mesma duração e intensidades, sendo exercício aeróbio: 15 min a 90% LA e exercício resistido: 15 min a 90%-12RM´s com 12-rep (6 exercícios). A PSE durante o exercício aeróbio foi mensurada aos 5, 10 e 15 minutos, na sessão CC foi mensurada a cada 3 minutos e durante o exercício resistido foi mensurada após cada exercício em cada série. Foi utilizada a escala de Borg de 15 pontos (6 – 20) para o exercício aeróbio e a escala de OMIN para o exercício resistido. A PSE apresentou diferença significativa entre as sessões experimentais em relação à sessão RA (13.1 ± 2.3; 15.7 ± 2.9, p<0,001) aos 5 minutos para AR (9.4 ± 1.6, p<0,001) e CC (9.1 ± 1.3) e aos 15 minutos somente para a sessão AR (13 ± 2.4, p<0,001). Na exercício resistido a PSE apresentou diferença significativa intra sessões no AR (8.0 ± 1.4; 6.9 ± 1.1, p<0,005) e na sessão RA (6.5 ± 1.4; 5.4 ± 1.3, p<0,005) em dois exercícios (puxada e leg press) (p<0,005) respectivamente. Concluindo, a ordem de aplicação do exercício concorrente na mesma sessão, altera as respostas de PSE em jovens atletas de jiu-jitsu.

The aim of this study was to investigate the response of perceived exertion (PE) in young athletes jiu-jitsu against different orders of application of aerobic exercise, resistance and combined (EC) . The study included ten young male athletes (22.6 ± 3.7 years, 70.3 ± 5.8kg , 175.9 ± 5.8 cm) , after being assessed for aerobic fitness (anaerobic threshold - AT) and strength (12 repetitions maximum - RM ‘s). The tests consisted of four randomized protocols, the sessions consisted of aerobic exercise followed by resistance exercise, RE followed by aerobic exercise, circuit (CC) (RE and aerobic exercise alternating intermittently) and control session (CO) (without exercise). All sessions had the same duration and intensity, AE: 15min at 90% of AT; resistance exercise: 15min at 90% of 12RM with 12reps (6 exercises). The PSE during the aerobic exercise was measured at 5, 10 and 15 minutes, only the session CC was measured every 3 minutes and during the RE was measured after each exercise in each series . We used the Borg scale for the aerobic exercise and scale OMIN to the resistance exercise. The PE was different between the experimental sessions over the session RA (13.1±2.3; 15.7±2.9 , p < 0.001) at 5 minutes to AR (9.4±1.6; p < 0.001) and CC (9.1±1.3) and 15 minutes for session only AR (13 ± 2.4; p<0.001) and in the resistance exercise was distinct intra PSE sessions AR (8.0±1.4; 6.9±1.1 , p< 0.005) and session RA (6.5±1.4; 5.4±1.3 , p<0.005) in two exercises (leg press and pull) (p<0.005) respectively. Therefore, the order of application of combined exercise in the same workout session, modifies the response of PSE in aerobic exercise and resistance exercise in young adult athletes.