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

Do current sports brassiere designs impede respiratory function?

PURPOSE: Although sports brassieres are more effective in limiting breast motion and related breast pain when compared with standard fashion brassieres, some females do not wear sports brassieres during physical activity, as they perceive them to be too tight around the torso, possibly impeding their performance during physical activity. The purpose of this study was to determine whether breast hypertrophy, breast momentum, and/or wearing a sports brassiere impeded respiratory function at rest and during physical activity. METHODS: Twenty-two active women completed standard resting spirometry maneuvers while not wearing a brassiere. All subjects then completed maximal cycle ergometer testing in two breast support conditions (sports brassiere and no brassiere (NB)), followed by submaximal treadmill exercise tests under three breast support conditions (sports brassiere, no brassiere and fashion brassiere) while standard spirometry, brassiere pressure and comfort were measured. RESULTS: The sports brassiere imparted significantly more pressure on smaller breasted females\u27 torsos when compared with the fashion brassiere (0.861 +/- 0.247 and 0.672 +/- 0.254 N.cm(-2), respectively), although this increased pressure did not appear to significantly affect measured lung volumes or brassiere comfort scores. Brassiere size affected maximal exercise ability (relative VO(2peak): smaller breasted NB: 49.84 +/- 6.15 mL.kg(-1).min(-1); larger breasted NB: 40.76 +/- 4.47 mL.kg(-1).min(-1)) as well as some temporal measures of resting and submaximal respiration. However, no significant difference was found between the no brassiere and brassiere conditions in regards to measured lung volumes. CONCLUSIONS: As no significant restriction to exercise performance or respiratory mechanics was found when subjects wore sports brassieres, it was concluded that active females should wear a sports brassiere during physical activity to reduce breast motion and related breast pain

Lactose-free milk prolonged endurance capacity in lactose intolerant Asian males

10.1186/s12970-014-0049-4Journal of the International Society of Sports Nutrition11

Força muscular respiratória de mulheres obesas mórbidas e eutróficas

A obesidade mórbida é uma condição clínica que afeta a capacidade funcional, sendo a musculatura respiratória igualmente comprometida. Objetivou-se avaliar a força muscular inspiratória e expiratória de mulheres obesas mórbidas (MO) e eutróficas (ME). Estudo transversal com amostra composta por 21 mulheres (14 MO e 7 ME), pareadas pela idade e altura. A avaliação da força muscular inspiratória e expiratória foi realizada por meio da verificação das pressões inspiratória e expiratória por manovacuometria. Quando comparadas as pressões respiratórias estáticas máximas obtidas com os valores preditos para ME e MO, constata-se que as do primeiro grupo apresentam valores de P Imáx=119,14±1,9 cmH2O (152% do predito) e P Emáx=141,1±10,2 cmH2O (98,5% do predito) dentro dos limites de normalidade ou acima, enquanto no grupo de obesas mórbidas os valores de P Imáx=66±18,7 cmH2O (84,3% do predito) e P Emáx=78,4±14,2 cmH2O (54,3% do predito) foram inferiores aos preditos. Comparando-se as pressões respiratórias estáticas máximas obtidas de MO com ME, observa-se diferença significativa tanto para os valores de P Imáx (66±18,7 versus 119±1,9 cmH2O) como P Emáx (78,4±14,2 versus 141,14±10,20) com significância estatística de 0,001. Conclui-se que a força muscular respiratória é marcadamente diminuída em MO, quando comparadas a ME.The morbid obesity is a clinical condition that affects functional capacity, and the respiratory muscles are also impaired. This study aimed to evaluate the inspiratory and expiratory muscle strength of morbidly obese women (OW) and eutrophic women (EW). Cross-sectional study, whose sample was composed by 21 women (14 OW and 7 EW) paired by age and height. Inspiratory and expiratory muscle strength evaluation was carried out by means of maximal inspiratory and expiratory pressure recordings (MIP and MEP, respectively) using manovacuometry. When comparing the maximal static respiratory pressures with predicted values for OW and EW, we observed that EW presented values of MIP=119.14±1.9 cmH2O (152% of predicted value) and MEP=141.1±10.2 cmH2O (98.5% of predicted value) within or above normal limits, while in OW group, MIP=66±18.7 cmH2O (84.3% of predicted value) and MEP=78.4±14.2 cmH2O (54.3% of predicted value) were lower than the predicted values. When comparing maximal static respiratory pressures of OW and EW, we observed a significant difference for MIP (66±18.7 versus 119±1.9 cmH2O) and MEP=78.4±14.2 versus 141.14±10.20) with statistical significance of 0.001. We conclude that respiratory muscle strength is notably decreased in OW when compared to EW