Age differences in physiological responses to self-paced and incremental V˙O2max\dot V O_{2max} testing

Purpose: A self-paced maximal exercise protocol has demonstrated higher $\dot V O_{2max}$ values when compared against traditional tests. The aim was to compare physiological responses to this self-paced $\dot V O_{2max}$ protocol (SPV) in comparison to a traditional ramp $\dot V O_{2max}$ (RAMP) protocol in young (18–30 years) and old (50–75 years) participants. Methods: Forty-four participants (22 young; 22 old) completed both protocols in a randomised, counter-balanced, crossover design. The SPV included 5 × 2 min stages, participants were able to self-regulate their power output (PO) by using incremental ‘clamps’ in ratings of perceived exertion. The RAMP consisted of either 15 or 20 W min$^{−1}$. Results: Expired gases, cardiac output (Q), stroke volume (SV), muscular deoxyhaemoglobin (deoxyHb) and electromyography (EMG) at the vastus lateralis were recorded throughout. Results demonstrated significantly higher $\dot V O_{2max}$ in the SPV (49.68 ± 10.26 ml kg$^{−1}$ min$^{−1}$) vs. the RAMP (47.70 ± 9.98 ml kg$^{−1}$ min$^{−1}$) in the young, but not in the old group (>0.05). Q and SV were significantly higher in the SPV vs. the RAMP in the young (0.05). No differences seen in deoxyHb and EMG for either age groups (>0.05). Peak PO was significantly higher in the SPV vs. the RAMP in both age groups (<0.05). Conclusion: Findings demonstrate that the SPV produces higher $\dot V O_{2max}$, peak Q and SV values in the young group. However, older participants achieved similar $\dot V O_{2max}$ values in both protocols, mostly likely due to age-related differences in cardiovascular responses to incremental exercise, despite them achieving a higher physiological workload in the SPV

High Resolution MEMS Accelerometers to Estimate VO2 and Compare Running Mechanics between Highly Trained Inter-Collegiate and Untrained Runners

BACKGROUND: The purposes of this study were to determine the validity and reliability of high resolution accelerometers (HRA) relative to VO(2) and speed, and compare putative differences in HRA signal between trained (T) and untrained (UT) runners during treadmill locomotion. METHODOLOGY: Runners performed 2 incremental VO(2max) trials while wearing HRA. RMS of high frequency signal from three axes (VT, ML, AP) and the Euclidean resultant (RES) were compared to VO(2) to determine validity and reliability. Additionally, axial rms relative to speed, and ratio of axial accelerations to RES were compared between T and UT to determine if differences in running mechanics could be identified between the two groups. PRINCIPAL FINDINGS: Regression of RES was strongly related to VO(2), but T was different than UT (r = 0.96 vs 0.92; p<.001) for walking and running. During walking, only the ratio of ML and AP to RES were different between groups. For running, nearly all acceleration parameters were lower for T than UT, the exception being ratio of VT to RES, which was higher in T than UT. All of these differences during running were despite higher VO(2), O(2) cost, and lower RER in T vs UT, which resulted in no significant difference in energy expenditure between groups. CONCLUSIONS/SIGNFICANCE: These results indicate that HRA can accurately and reliably estimate VO(2) during treadmill locomotion, but differences exist between T and UT that should be considered when estimating energy expenditure. Differences in running mechanics between T and UT were identified, yet the importance of these differences remains to be determined

Effects of intermittent hypoxic training on cycling performance in well-trained athletes

Belle Roels, David J. Bentley, Olivier Coste, Jacques Mercier, Grégoire P. Mille

Efeitos de diferentes modelos de periodização do treinamento aeróbio sobre parâmetros cardiovasculares, metabólicos e composição corporal de bombeiros militares

O objetivo do estudo foi analisar o efeito de programa de treinamento aeróbio sobre parâmetros cardiovasculares, metabólicos e de composição corporal comparando diferentes periodizações. Sessenta e cinco bombeiros militares/ES (25,9 ± 0,6 anos) foram divididos em quatro grupos: controle (Gcon, n = 15) sem tratamento; ondulatório (Gond, n = 18), escalonado (Ges, n = 17), e crescente (Gcres, n = 15), e treinaram 13 semanas, três sessões semanais de 30 minutos e intensidades de 60% a 90% FCmáx. A frequência cardíaca (FC) foi controlada em todas as sessões . Antes e após o programa foram realizadas avaliações antropométricas e teste cardiopulmonar (Aerosport TEEM-100). Houve redução no percentual de gordura, bradicardia em repouso e da FC submáxima com aumento do consumo de oxigênio, e redução do duplo produto, da PAD em repouso para os três grupos treinados, sem vantagens adicionais para o Gcres. Esses resultados sugerem que programas de treinamento aeróbio com distribuição de intensidade ao longo das semanas de forma escalonada e/ou ondulatória podem ser mais apropriados para indivíduos não atletas